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Design of an Autonomous Platform for Search and Rescue UAV

1. cceccecceeceeeeeeeeeeeteeeeeeees 87 Figure 100 Software integration team s GUI used to view the path of the UAV during a search and Keele BE 88 xii List of Tables Table 1 this table Identifies which flight characteristics are effected by different Design Parameters DEEN 10 Table 2 Power board SPe CITICATIONS ccc cece ecccececeeeceeece cece nR EE ARRA A 29 Table 3 Test day summary results based ON outcomes n nnennennennennenenoennrrrrrnrrrrrrrrrrrrrrrrrrrrrernne 34 Table 4 Shows the different types of support that we completed preparations for on the different agel eE E E A E A T TT AE ETE T A AA N E 40 Table 5 Shows the different types of support that we Implemented on the different airplanes 40 Table 6 Decision matrix for determining which autopilot system the team use 49 Table 7 Decision between using a paparazzi autopilot board verses using a development board 49 Table 8 Decision between which paparazzi autopilot board tO USE ccccceceeeeeceeeneeeneeeneeeneeenes 50 Table 9 Autopilot goals This table lays out the autopilot goals and whether they were achieved partially achieved or NOt met 77 Table 10 Summarizes the how successfully we accomplished all of our Goals during this project EE 89 xiii 1 Introduction Hiking is a very popular activity for people across the globe Some hikers are leisure seekers looking to get away from the sights and sounds of a big city and escap
2. Airframe The airframe configuration file consists of the assignment of configuration files for all subsystems and sensors Also included are the definitions of the control surfaces and their behaviors and the defaults for many flight parameters A configuration file system allows Paparazzi to be flexible with new sensors or other subsystems by allowing the user to define new configuration files and associating them with their corresponding sensors or subsystems within the airframe file Telemetry The telemetry configuration file defines the messages used for plane to base station communications All of the messages within the telemetry are transmitted by the UAV and then displayed at the ground station within the messages window This allows for debugging of the plane and its various subsystems on the ground and during flight All messages are saved for review after the flight Each type of message has a period defined This allows for less important messages to be slowed down reducing data transmission lt message name AIRSPEED period 1 gt lt message name ALIVE period 5 gt lt message name GPS period 0 25 gt lt message name NAVIGATION period 1 gt lt message name ATTITUDE period 0 5 gt lt message name ESTIMATOR period 0 5 gt lt message name ENERGY period 2 5 gt lt message name WP_MOVED period 0 5 gt lt message name CIRCLE period 1 05 gt 129 lt message name DESIRED perio
3. 5 Select the modem configuration tab 6 Hit Read to check the current firmware 7 Confirm the following settings e PANID 3332 e Destination Address High 0 e Destination Address Low FFFF e Coordinator 1 Coordinator e Interface Data Rate 57600 e API Enabled 1 API Enabled 8 Now hit Write to update the Xbee 9 Place an End device into the usb connector 10 Hit Read to update the window with the end devices configuration 11 Confirm the following Settings e PANID 3332 e Destination Address High 0 e Destination Address Low FFFF e Coordinator 0 End Device e Interface Data Rate 57600 e API Enabled 1 API Enabled The only difference is the destination that this is an end device Having the Destination address set to FFFF has the xbee radios transmit to all radios in the area Since this network is in a star topology with only end devices talking to the coordinator other end devices will ignore each other The GCS will receive packets from the Autopilots and parse them based on the aircraft identification number for each autopilot Now that the radios are loaded with the correct firmware the following change is required within the airframe configuration file to make use of the Xbee API lt subsystem name telemetry type xbee_api gt lt configure name MODEM_BAUD value B57600 gt lt subsystem gt Build and upload the new configuration and connect to the autopilot using Flight USB X Bee API 5760
4. D1 Reverse recovery currents degrade performance and de crease efficiency For these reasons a Schottky diode of appropriate ratings should be used for D1 The voltage rating of the boost diode should be equal to VOUT plus some mar gin Since D1 only conducts during the buck switch off time in either mode the current rating required is D4 A Schottky type re circulating diode is required for all LM5118 applications The near ideal reverse recovery characteristics and low forward voltage drop are particularly important diode characteristics for high input voltage and low output voltage applications The reverse recovery characteristic determines how long the current surge lasts each cycle when the buck switch is turned on The reverse recovery characteristics of Schottky diodes minimize the peak instantaneous power in the buck switch during the turn on transition The reverse breakdown rating of the diode should be selected for the max imum VIN plus some safety margin The forward voltage drop has a significant impact on the con version efficiency especially for applications with a low output voltage Rated current for diodes vary widely from various manufacturers For the LM51 18 this current is user selectable through the current sense resistor value Assuming a worst www national com 18 case 0 6V drop across the diode the maximum diode power dissipation can be high The diode should have a voltage rat ing of VIN an
5. R2 A 1M pull up resistor connected from the EN pin to the VIN pin is sufficient to keep enable in a high state if on off control is not used 19 SNUBBER A snubber network across the buck re circulating diode re duces ringing and spikes at the switching node Excessive ringing and spikes can cause erratic operation and increase noise at the regulator output In the limit spikes beyond the maximum voltage rating of the LM5118 or the re circulating diode can damage these devices Selecting the values for the snubber is best accomplished through empirical methods First make sure the lead lengths for the snubber connections are very short Start with a resistor value between 5 and 20 Ohms Increasing the value of the snubber capacitor results in more damping however the snubber losses increase Se lect a minimum value of the capacitor that provides adequate clamping of the diode waveform at maximum load A snubber may be required for the boost diode as well The same em pirical procedure applies Snubbers were not necessary in this example Error Amplifier Configuration R4 C18 C17 These components configure the error amplifier gain charac teristics to accomplish a stable overall loop gain One advan tage of current mode control is the ability to close the loop with only three feedback components R4 C18 and C17 The overall loop gain is the product of the modulator gain and the error amplifier gain The DC modulator gain of
6. 3 The Spotter The spotter is a specific role for when there are multiple robots in operation He or she is the big picture safety person It is the responsibility of the spotter to Watch the robots as they fly and in particular watch for impending collisions between planes and object on the ground like trees buildings and people In the event of an impending collision please inform the communications runner to avert said collision 4 The Communications Runner The communications runner is a specific role for when multiple robots are in operation It is the responsibility of the communications runner to ensure accurate communication between the different flight controllers the spotter and the ground controller 103 5 Each additional flight controller one for each additional robot in the test over 1 because each robot has to have a unique flight controller each with its own radio transmitter being controlled by the individual flight controllers These additional flight controllers have equal stature in the hierarchy and need to take commands from both the ground controller and the chief flight controller Procedural Safety Every time a robot is expected to fly these are the steps to be taken to ensure safe operation of the robots for WiND personnel as well as spectators 1 Location Selection The first consideration to take is to understand the size of both the robot being flown as well as the size of the flight path to be flown
7. Aircraft Safety Code This example is not intended to represent the specific needs of all flying sites It is rather intended to de a puide to help each club develop rules which specifically meet the individual site situation 112 Appendix E Master Budget List Senior telemaster Hitec HS 322 Servo RCG 20 cc Gas engine propellor 16x4 Opto Gas Kill Switch 9 Channel remote Batt for Ign Charger Re fueling pump Fuel Lines for pump Starter Propeller Tank 320z Re fueling ports Fuel Line Fuel Filter 106 Giant Scale 30 50CC Skyline Champ RCG 30cc Gas engine Hitec HS 322 Servo Opto Gas Kill Switch DX6i radio system Quick Disconnect valves Clear Domes Power HD High Torque Servos gimbal Yapa2 Autopilot MediaTek GPS MPXV7002DP Airspeed Thermopiles Propellor 18x6 Total Price 209 99 9 99 159 99 2 39 11 83 89 00 15 00 16 00 24 00 5 00 25 00 12 00 10 50 16 69 5 00 3 47 299 00 223 00 9 99 11 83 209 99 17 00 30 00 20 00 80 00 38 00 25 00 140 00 15 29 Quanty 1 5 1 2 1 1 1 1 1 1 1 2 1 2 3 3 N total 209 99 49 95 159 99 4 78 11 83 89 00 15 00 16 00 24 00 5 00 25 00 24 00 10 50 33 38 15 00 10 41 598 00 446 00 119 88 23 66 209 99 68 00 30 00 0 00 160 00 76 00 25 00 280 00 30 58 2 770 94 113 Appendix F Detailed Flight Log Detailed Flight Log The next step towards
8. Pulleys are better at not 23 transferring and magnifying vibrations than gears however the vibrations will cause them to slip and the actual location will be off from the expected location Over the duration of the flight it could completely shift our range of motion away from the ground A string in a pull pull set up with the Servo was considered though the string will not help absorb the vibrations and over time will be worn out and begin stretching Since the linkage system is made from spring steel which deflects under the faster vibrations while remains solid when responding to the servo it successfully absorbs the vibrations without compromising its functionality However the pan rotational motion was done with a pulley system because it was not going to be largely effected by the vibrations The pan motion was not supporting a rotating mass that contained inertia It was also mounted perpendicular to the majority of the vibrations in the system This entire structure is supported on vibration dampening rubber that isolates it from most of the airplanes vibrations First the elastic properties of different materials typically used in vibration dampening mounts like rubber and silicon were researched The team was also able to find several data sheet that showed the frequency ranges for different silicon dampeners Based on the engine data sheet the engine would be running between 30 and 40 Hz while flying The graphs in Figures 25 26 an
9. Solder to the ground plane under the IC to aid in heat dissipation 3 www national com 8 LLGNT LM5118 Absolute Maximum Ratings Note 1 RAMP SS COMP FB SYNC RT to GND 0 3 to 7V pe e l ESD Rating If Military Aerospace specified devices are required HBM Note 2 o kV please contact the National Semiconductor Sales Office 4 S Distributors for availability and specifications Storage Temperature Range 55 C to 150 C Junction Temperature 150 C VIN EN VOUT to GND 0 3V to 76V VCC LO VCCX UVLO to GND Note 5 0 3 to 15V Operating Ratings Note 1 HB to HS 0 3 to 15V VIN Note 4 3V to 75V HO to HS 0 3 to HB 0 3V VCC VCCX 4 75V to 14V HS to GND 4V to 76V Junction Temperature 40 C to 125 C CSG CS to GND 0 3V to 0 3V Electrical Characteristics Limits in standard type are for T 25 C only limits in boldface type apply over the junction temperature range of 40 C to 125 C Unless otherwise specified the following conditions apply VIN 48V VCCX OV EN 5V RT 29 11 kQ No load on LO and HO Note 3 VIN SUPPLY IstpBy VCC REGULATOR WIN Shutdown Curent Jez i o VOC Sourcing Curemtmt vccz0 a s m VCOX Switch threshold vocx Risng s68 385 402 v VCOXSwitchhysterisis T lo Tv vcoxswionRoson Jomes s rla Ca E A VCCCX Pull down Resistance Pull down Resistance VCCX 38V sd 3V kQ EE Ge VCC Under VCC Under Voltage Hysterisis Hysterisis Ss ee ee eee V H
10. Using an RC simulator is a great place to start or to hone in and improve your skills even as an experienced pilot The greatest benefit to using a simulator is that if you crash you can simply restart the program and try again without all the time and money that it takes to have to rebuild or replace your plane However you should still take the simulator seriously because you should not develop bad habits in the early stages of learning to fly One of the biggest challenges of learning to fly RC is the orientation When flying the plane if you change the directions from going away from you to toward you left and right become reversed This is the biggest challenge even sometimes for experienced pilots The trick to overcoming this is not to think of it as it needs to go right or left but more of opposite of what it did In practice try a slight course change and correct as needed Flying is more of an action reaction experience and that is the best and simplest way to think of it After you have spent several hours on a simulator the next logical step is to go to a buddy box system This allows you to fly your plane with and experienced pilot to help prevent crashes This system works by using a cable to link two transmitters together that will allow the experience pilot to flip a switch and then have full control of the plane There is also another great benefit to this system because you can get valuable feedback from the pilot of what you did w
11. level and thereby set the off time of the hiccup mode fault protection An internal 5 pA pull up current pulls the UVLO pin to a high state to ensure normal operation when the VIN UVLO function is not required and the pin is left floating Oscillator and Sync Capability The LM5118 oscillator frequency is set by a single external resistor connected between the RT pin and the AGND pin The R resistor should be located very close to the device and connected directly to the pins of the IC To set a desired os cillator frequency f the necessary value for the R resistor can be calculated from the following equation 6 4 x 102 3 e e 3 02 x 10 R The SYNC pin can be used to synchronize the internal oscil lator to an external clock The external clock must be of higher IA Les Pr 1 23V Www SUL frequency than the free running frequency set by the R re sistor A clock circuit with an open drain output is the recom mended interface from the external clock to the SYNC pin The clock pulse duration should be greater than 15 ns LM5118 SYNC LM5118 SYNC UP TO FIVE LM5118 DEVICES 30058518 FIGURE 7 Sync from Multiple Devices Multiple LM5118 devices can be synchronized together sim ply by connecting the SYNC pins together In this configura tion all of the devices will be synchronized to the highest frequency device The diagram in Figure 7 illustrates the SYNC input output features of the LM5118 The
12. one color camera and one infrared camera These specifications are necessary metrics for the success of the project For example it is important for the flight time to be in excess of 1 hour Otherwise the UAVs will be unable to cover any significant area per fueling which would make the system a hindrance as opposed to an asset to the search teams Similarly the power and maximum payload requirements are also important and have been derived from the needs of the other teams of project WiND With a system that meets these specifications the network will be capable of flying up to 30 miles on a single flight The efficiency of the search algorithm varies depending on the terrain being searched as well as other factor however this would translate to a round trip search of 38 250 000ft2 at 400 feet in altitude per aircraft The success of the project was determined based on the completeness of these specifications at the end of the project There is a need for a more efficient easier and safer way to search for lost and injured hikers in mountainous regions Our proposed network of UAVs will ultimately create a safe and efficient way to search vast amounts of wilderness without putting rescuers at risk while still giving the victims the assistance they require 2 Platform Development The first portion of this project was to develop a platform capable of both autonomous flight and supporting higher level functions for the network This sect
13. 30cc gasoline engine for the Skyline Champs We choose to go with gas engines over nitro and electric because it was more cost effective for the flight times based on our specifications We added an aluminum frame and a plywood floor to the Senor Telemaster airframe The aluminum was added to provide a hard mounting point and to protect the electronics and to support our modified wings attachment points The wings on the Telemaster were designed to be attached with large rubber bands because of our large payload we added bolts and pegs The plywood floor supports our camera dome gimbal and Xbee radio MED a mm J Ze SZ e i _ a e r Sr E D K a W 3 SW ES E wi Ba as As Figure 1 Telemaster Airframe out at the Airport Figure 2 Blue Skyline Champs Airframe out at the Airport Our camera gimbal can support up to two cameras a colored and infrared camera The final implementation only included the color camera This gimbal serves two main purposes to increase the field of vision of the cameras and dampen the vibrations from the engine and propeller Its main source of dampening is a layer of foam based silicon isolating it from the plane and a spring steel linkage system that absorbs more of the vibrations that can be amplified by the inertial properties of the camera 4 PLATFORM TESTING We traveled out to Tanner Hiller Airport seven times to test our planes with a majority of the tests in Febru
14. 736437251259 46093 277 5 220330002 T TR SENSORS SIL gt La aid S11 oo DOWNLINK STATUS 9 4420 208 1 522 23 14 42 DESTRED Os Oga Os Ge Gy DU Ek PPM 40 2467 7 7246 0 2446271060U6 39906 20016 NAVIGATION 2 1 EE ek Why 3643 07 0 GPS 3 V249 Er 24 159030 6 S20 bese Eh EE I9 1I RG EE Ee COMMANDS EE e er Hl E ESTIMATOR 1897070597 O EE ENERGY E Lo EE NAVIGATION 2 L Lli Sl ie Eeer ER 0 GPSS PSOALOLZ AGI8 245 07 O74 lee be Lo eye Al EE ded a W WWW WWW WWW WWW WWW WWW WWW WWW WWW LO W 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 2 9 9 9 9 9 9 9 9 G 9 Figure 92 Data Acquisition during Manual Autopilot control This portion of data shows RC messages with complete RC commands from the remote controller and updated GPS positions 78 Figure 93 Autopilot data acquisition during RC flight This figure alternates between the ground control station displaying the UAV s position and the UAV flying Figure 93 demonstrates a pure RC flight in which the autopilot was placed into the plane for telemetry transmission The data was received from the autopilot within the plane was parsed to display the planes position within the ground station UI The first two images display the plane coming around the end of the runway and then turning to come back down The UI then shows the plane turning around again and then coming back 3 3 3 Flight through the autopilot Once the configuration file was complete
15. Crash ccccccceececeeeeeeeeeeeeeseeeeaeeeseees 37 Figure 45 Camera behind Robin s dome before its April 11th flight cc cccceeeesseeeeeeeeeeeeneees 38 Figure 46 What was left of Robin s body after the April 11th Flight All of the electronics survived LNG GAS DE 39 Figure 47 Altitude Plot based on our February 2nd obt 40 Figure 48 Velocity plot from our February 2nd flight cccccccccsececeeceseeeeeeeeceeeeseeeseeeeseesaeeesaees 41 Figure 49 Camera image with the engine off when the camera is mounted properly with vibration Sie le 41 Figure 50 Camera images with the engine on when the camera is simply taped to the bottom of ENEE eebe 42 Figure 51 Autopilot Flow Chart This chart represents the flow of how the autopilot system interfaces between the UAV in the air and the user controlled ground station ccceeeeeeeeees 43 Figure 52 Piccolo autopilot system Piccolo is an all in one solution for autonomous flight provided by MIT http www cloudcaptech com piccolo ehm 44 Figure 53 Ardupilot is an open source autopilot solution featuring arduimos eens 45 Figure 54 Paparazzi autopilot system This particular version is named VADAZ 46 Figure 55 IR Response Curve This curve represents the response of the thermopiles as the angle of the plane is changed http paparazzi enac fr wiki File Ir_reSpOnSe_CUrve Off 47 Figure 56 IR Thermopiles They are in charge of providing flight stabilization for a
16. For more information about where the hardware team is allowed to stand during startup see definition of the Hot Zone around the Robot and figure 0 1 above Other Procedures Emergency Landing Protocol There are two different scenarios for emergency landings One is an unscheduled landing which is defined as any time the auto pilot faults out and the robot is taken over by the human flight controller and is brought down by for inspection The urgency to land in this scenario is not pressing and it is advised for the flight controller to regain full control of the robot and all the aircraft functions announce the landing to the ground controller and any other flight controllers and then proceed to carefully bring the robot in for a landing The timing for such an event is to be scaled in minutes An emergency landing is defined as a loss in a major flight control system such as the loss of control of the rudder or ailerons etc and subsequent loss in the auto pilot In this case the urgency to bring the robot down safely is at its highest The flight controller is to take control of the robot and land in any area that they deem fit even if this is outside of the hot zone The first priority is to avoid people The second priority is people s property so avoid homes and buildings as well as cars that may be parked nearby The third is to bring the robot down with as little additional damage as possible This process should take place i
17. However they do scale down comparatively Flat Bottom Symmetrical airfoils are for aerobatic airplanes Semi symmetrical irfoil f i ilpl alriolis are for secondary trainers sal p anes and sport aerobatic Figure 10 Airfoil Geometry biplanes Flat bottom and modified flat bottom airfoils are used for slow Reflexed gentle flight Under cambered airfoils are used for scale models and sailplanes Reflexed airfoils are used for fling wings When picking an airfoil it is important to know the amount of lift stall characteristics leading edge radius and intended purpose that each airfoil style has Wing Loading Wing loading is the measurement of weight carried by each unit of area The lower the wing loading the slower the plane will lift off fly and land The higher wing loading the more predictable the plane is when landing less responsive to controls and must fly faster to stay in the air Wing loading is typically measured in oz ft Johnson 2007 and includes the surface area of both wings This number 10 in combination with the expected ready to fly weight can be used to calculate the appropriate wing area Aspect Ratio The aspect ratio is the ratio of the wingspan to its chord or width This ratio affects the roll rate lift to drag ratio and pitch sensitivity This means that it also affects fuel efficiency and the planes tendency to tip stall However if the aspect ratio is too high it will have sluggish response to rol
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19. PEAK 13 34A An acceptable current limit setting would be 6 7A for buck mode since the LM5118 automatically doubles the current limit threshold in buck boost mode The selected inductor must have a saturation current rating at least as high as the buck boost mode cycle by cycle current limit threshold in this case at least 13 5A A 10 UH 15 amp inductor was chosen for this application R13 Reense To select the current sense resistor value begin by calculat ing the value of Rsgense for both modes of operation 1 25V HI Auch AO x Mex For the buck boost mode Rsense IS given by 2 5V R1 3 BUCK BOOST 10x EE PEAK A Rsenge Value of no more than 18 7 mQ must be used to guarantee the required maximum output current in the buck boost mode A value of 15 mQ was selected for component tolerances and is a standard value R13 15 mQ C15 Cramp With the inductor value selected the value of C3 necessary for the emulation ramp circuit is Lx10 C19 Cramp 2 X Rgense With the inductance value L1 selected as 10 UH the calcu lated value for Caanyp is 333 pF A standard value of 330 pF was selected C9 C12 OUTPUT CAPACITORS In buck boost mode the output capacitors C9 C12 must supply the entire output current during the switch on time For this reason the output capacitors are chosen for operation in buck boost mode the demands being much less in buck op eration Both bulk capacitance and ESR mu
20. THRO function THROTTLE min 1100 neutral 1520 max 2020 lt radio gt average 0 gt average 0 gt average 0 gt average 0 gt average 0 gt Figure 70 Radio Configuration File This file defines the structure of the PPM signal received from the MeekPe encoder board The radio configuration file defines the channels seen within the PPM signal and parsed based on the parameters shown in Figure 70 The order of the channels is dependent on the receiver Autopilot modes The autopilot has three main operating modes which are selectable from the radio controller by the mode channel e Manual Provides full control over all of the UAV s control surfaces as if it was a normal RC plane This mode will be utilized for taking off and landing the UAV during initial autopilot testing This mode is also FAA mandated e Autol Engages the autopilot to fly the plane straight but still allows the user to turn the plane slightly and control the throttle and rudder This will be our main method for testing the autopilot during its first few flights to ensure that the control system functioning properly 60 e Auto2 Fully engages the autopilot and has it follow the flight plan defined in the flight plan configuration file This is the full autopilot for taking off landing and navigating way points For the scope of this project the team intends to have the UAV navigate GPS waypoints only Using the radi
21. Te L anzol 24 IN O ST 4AN OST M ANZ a OT OI t eto eta 6J eee c ZO Gi Linon er GEOTOYAN YE a AZT LNON NID dee FaN ONG ger ONG Y N gN GU k i A anz z anzz anzz anzz anzz G e J z3 tT NBL 9 Ne NIN E Az gt www national com 23 LM5118 Physical Dimensions inches millimeters unless otherwise noted EXPOSED PAD AT BOTTOM 4 440 1 1 BH e siii 20X 0 42 e K d Ao 2 c B A RECOMMENDED LAND PATTERN ALL LEAD TIPS SEE DETAIL A MAX Tie 0 9 a e Serr N HS are i l zox 0 19 0139 Is 140 05 TYP ALL LEAD TIPS EEGA gt 18x SR 12 TOP amp BOTTOM RO 09 MIN RO 09 MIN GAGE PLANE 0 8 DIMENSIONS ARE IN MILLIMETERS Fi S DIMENSIONS IN FOR REFERENCE ONLY e K 7 0 6 0 1 SEATING PLANE 1 DETAIL A TYPICAL MXAZ20A Rev C TSSOP 20EP Outline Drawing NS Package Number MXA20A www national com 24 Notes 25 www national com SLLSIN LM5118 Wide Voltage Range Buck Boost Controller Notes For more National Semiconductor product information and proven design tools visit the following Web sites at www national com amplifiers WEBENCH Data Converters Distributors Interface Quality and Reliability wireless PLEO ee THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION NATIONAL PRODUCTS NATIONAL MAKES
22. Voltage lo 100 mA Wl a V Vouu Vip Vou HORiseTime sst III Is HoraTme caan vocz In HB HS Under VotageLoceout v BUCK BOOST CHARACTERISTICS Buck Boost Mode Buck Duty Cycle Note 9 69 75 a THERMAL Thermal Shutdown Hysterisis oO D a C C W 5 www national com SYNC V 3 lt 8LLGNT LM5118 Note 1 Absolute Maximum Ratings are limits beyond which damage to the device may occur Operating Ratings indicate conditions for which the device is intended to be functional but does not guarantee specific performance limits For guaranteed specifications and test conditions see the Electrical Characteristics Note 2 The human body model is a 100pF capacitor discharged through a 1 5 kQ resistor into each pin Note 3 Min and Max limits are 100 production tested at 25 C Limits over the operating temperature range are guaranteed through correlation using Statistical Quality Control SQC methods Limits are used to calculate National s Average Outgoing Quality Level AOQL Note 4 5V VIN is required to initially start the controller Note 5 When the duty cycle exceeds 75 the LM5118 controller gradually phases into the Buck Boost mode www national com 6 Typical Performance Characteristics GAIN dB EFFICIENCY Vcc V Efficiency vs VIN and IOUT VOUT 12V 30058503 VCC vs VIN 10 8 6 4 2 0 0 2 4 6 8 10 12 Vin V 30058505 Error Amplifier Gain Phase
23. altitudes the plane achieved during the test based on sea level Based on this chart it is known that the airframe reached over 1000 feet and averaged around 200 ft Figure 48 shows the Velocities for the same flight test Altitude Plot 2 02 2012 15 18 43 Altitude Meters N N N UJ CH On CO CH ro ta N N O 200 Altitude 0 50 100 150 200 250 300 350 400 450 Time s Figure 47 Altitude Plot based on the February 2nd flight 40 Velocity Plot 2 02 2012 15 18 03 35 30 25 20 15 Velocity Meters second 10 Velocity o 50 100 150 200 250 300 350 400 450 Time s Figure 48 Velocity plot from the February 2nd flight Gimbal Results During the first Robin flight a hard mounted camera was installed to the bottom of the plane and recorded footage of the flight During the last Robin flight a camera was added to our camera gimbal therefore utilizing the vibration dampening pads Its footage cut out while the plane was still on the ground but the team was able to compare the images of the ground with the engine running for these two cameras Figure 50 shows a screen capture of the footage from the camera hard mounted to the bottom on the first flight Figure 49 shows a screen capture of the footage from the camera mounted in the plane with vibration dampening Notice the distinct sine waves in the image that was hard mounted to the frame as compared to the footage with vibration dampening Eliminati
24. and the radio encoder board was installed the team successfully flown Robin on two separate occasions through the manual mode of the autopilot 79 Time 0 33 Time 0 42 Te o Time 032 Time 0 48 Figure 94 Successful takeoff using the manual mode of the autopilot Figure 94 demonstrates a successful take off of the plane using the manual mode of the autopilot The above images are of the final takeoff of Robin before it s unfortunate crash 3 3 4 Connection to multiple planes with data acquisition After configuring the xbee radios into a Zigbee network the team was able to connect to two Separate autopilot controllers with separate aircraft id s to distinguish the two within the data and the ground control station 80 wwe GCS Nav Maps Help Ce wase4 42 355716 72 130700 1 01 gt Jay SkylineChamp TelemasterTest La ACTUATORS uint32 run_time s 191 AIRSPEED uint32 rx_bytes 119050 ALVE uint32 rx_msgs 4592 ATTITUDE Le BAT ge uint32 rx_err 0 i CALIBRATION Float rx_bytes_rate 729 COMMANDS _ Float rx_msgs_rate 29 DESIRED PR Float ping_time ms 213 3 DL VALUE DOWNLINK DOWNLINK_STATUS 1 ENERGY ESTIMATOR 7 FBW_STATUS p dayeStalinechamp Telem
25. assignment of configuration files for all subsystems and sensors Also included are the definitions of the control surfaces and their behaviors and the defaults for many flight parameters A configuration file system allows Paparazzi to be flexible with new sensors or other subsystems by allowing the user to define new configuration files and associating them with their corresponding sensors or subsystems within the airframe file All UAV s involved will need to set up the following subsystems and sensors in order to run the autopilot Xbee Radios To confirm that the team has properly set up all of our sensor configurations XBee radios were used to transmit all sensor readings back to the ground station See Appendix G User Manual Xbee Connection 51 EUP 6 SS lt O a H x So a 22 8 SAR 3 a a Ground Control Station Coordinator Xbee Figure 58 Paparazzi autopilot system showing the ground control station coordinator Xbee for connecting the ground station to the Xbee located on the Yapaz For multi plane communications the Xbee radios had to be configured to use the Xbee API protocol which allows for local mesh networks This involved updating the firmware for each of the Xbee radios used See Appendix G User manual Xbee Connection for more information Once the firmware was updated on the Xbee radios the radios were installed on the two separate autopilot boards and communication was established to
26. autopilot and its necessary sensors into the airplane Before taking the UAV to the airfield for autopilot testing we confirmed that all of the components of the autopilot were working as anticipated This helped save debugging time on the field and prevented any unnecessary trips back to the field Within the lab we confirmed the operation of the following components e XBee communications o Verified by connecting to the plane via the ground station software with the message window receiving messages e GPS o Verified by viewing messages received from the GPS within the messages window e IR Thermopiles o Verified by viewing the message window for IR Thermopile readings The readings should be varied due to indoor IR noise e Manual Mode o Verified by toggling the mode switch on the radio controller Within the messages window and the ground station the mode should switch to Manual Mode There should be full control over all of the control surfaces with the radio controller o All of the servo throws have to match the servo throws produced by the radio receiver by itself This is to ensure normal flight control with Manual mode e Auto 1 Mode o Verified by switching the mode switch to the Auto position and observing the plane The control surfaces should attempt to stabilize the plane based on the IR Thermopile noise within the room In addition the messages window and the ground control station should display that the UAV is in AUTO1
27. beginning These goals are summarized in Table 10 the right hand column summarizes how well we accomplished these goals during this project For more detailed results on this project see the results sections imbedded in the Platform and Autopilot sections Those sections cover detailed results on the simulations gimbal performance flight tests and power board Table 10 Summarizes the how successfully we accomplished all of our Goals during this project Three fully autonomous fixed wing aircraft nee OO a Bee a a a Capable of flying between 120 ft and 400 ft of altitude as specified by the FAA for UAVs Capable of supplying 102 watts of power to on board electronics for a minimum 1 hour per fag SD Contains a pan tilts camera gimbal capable of holding up to two cameras one color camera and meneame nn We only got half a smiley on having three fully autonomous fixed winged aircrafts because we were only able to get one flying under assisted flight and one under RC flight so we didn t fully meet our goals We were unable to have any of them fly under Auto 2 because Robin crashed and we didn t have time to repair him before the project ended Capable of maintaining flight without refueling for a minimum of 1 hour We gave our selves a full frown face on our third objective because we never got Auto2 to work on the real planes only simulation which was in charge of way point navigation However in Simulation we were abl
28. dependent on the input voltage and the highest efficiency is when Vin is around 18V which is near the voltage of both a 4 cell 14 8V and a 5 cell 18 5 Lithium Polymer battery 29 Efficiency vs VIN and lOUT VOUT 12V EFFICIENCY Vin V Figure 34 LM5118 efficiency curve Jip VIN US UIN 4U to 7 U C1 C2 c3 C4 c5 2 2 UF 2 2 uF 2 2 UF 2 2 UF 2 2 uF GND Mw siet Qin VOUT 12U 3A J3 T VOUT 7 L15118 wae ca c10 c13 dpia Jeu c12 a 47uF 47uF 18 uF 160 UF 0 47 UF 0 47 uF C24 0 1 uF J4 D RTN TPL AGND Figure 35 Standard configuration for buck boost regulator 30 DI came ice EEL Si HI OK 3 i el nom D G e e CMS EI E S WW an Ti L t SI P E Ze see Lata kA FL HS E Te Ki Lk BERENS Ter Figure 36 Configuration used in our schematic For the control logic for this system an MSP430 was used A simple controller was needed to monitor the current battery voltage and to control the enable lines on all the regulators Using a microprocessor for this simple task is unnecessary however the decision was made because it would leave room for expansion for future project groups and allow the system to be easily adapted if the battery type is changed 3 3Vde for uProcessor LT1762 MSS A a C2 c3 c5 luf X7R 603 0 luf X7R 603 S RO SERVOS Par AUTOPILOT Par PANDA Par WIFI Pwr SDR Pwr Radio Amp Com
29. for the rudder was too slow and replaced with a faster servo Due to inclement weather we were unable to fly at all during the months of December and January so our next flights occurred in February During December and January we made several additional modifications to the plane We moved the gas tank back 4 inches to help with keeping a consistent center of gravity as the fuel weight decreases with time during a flight which increased our overall flight stability Moving the gas tank bank also allowed us to move the throttle servo to the front of the plane closer to the engine In this new position the linkage still needed some work and was still giving a nonlinear response making it difficult to adjust speed efficiently We also put a nipple on the muffler to pressurize the gas tank With these corrections we were ready for the weather to break and continue testing February 2 flight During this flight we were able to test the GPS down link and we flew Robin without refilling the gas tank for 30 min However our joint of J B weld epoxy holding the new nipple to the muffler for pressurizing the gas tank melted leaving a hole in the muffler This did not stop us from making more flights however During the next flight an aggressive move maneuver caused the wings to shift enough to sheer off one of the connection point of the wing struts For future flights we reduced the throw on the control surfaces for gentler movements Our fix for this w
30. i 150 KI UI NUTT mt IN 90 UNTI U I N i j nh i IK TV N Ji 0 TN N 30 E 04 1E 05 1E 06 1E 07 FREQUENCY H2 PHASE 30058507 CURRENT LIMIT THRESHOLD mV Vec V Current Limit Threshold vs VOUT VIN VOUT 12V 10 CO O gt N 5 70 75 80 85 90 95 100 105 110 VoutT Vin DC 30058504 VCC vs IVCC 0 10 20 30 40 50 IVcc mA 30058506 LO and HO Peak Gate Current vs Output Voltage CURRENT A VCC 8V HO Source FA L ECCL OUTPUT VOLTAGE V 30058508 www national com SLLSIN LM5118 Fosc kHz www national com Oscillator Frequency vs RT 20 40 60 80 100 120 140 160 RT kQ 30058509 LM5118 ircul Block Diagram and Typical Application C L SYNDlA Ol S8S00 TOYLNOD ACOW WW 1soog yong EH vil OG UIA X yri g s00q yonq dE d E ric dien ga vil og 3noA UIA x yg ona YOLVTIIDSO E i ZO Ce YOLVYANAD dien y Ou GH A N 6 CL EM G10H V A SY OL pue MOVAL Aos z 800q 0nd YA Sei ge ZL AGZLzs 19NqG WA 8 Via x L ca bk SH H BS DS WMd el OH ie Q LO 19 ss fz WoL AN YAWIL LINvA UIA AGOW dNDOIH AEZ Zu ZLO own z E Sec ON SH che Q ke eho AGGNVLS ANY NMOGLNHS SEHR 8h 7JYWYIHL E ABE Ee ZO LO 89 OTAN DOA So YOLVINOAY S OLE ODA AL L AGZ Apr NIA SLLSIN D www national com LM5118 Detailed Operating Description The LM5118 high voltage
31. internal os cillator circuit drives the SYNC pin with a strong pull down weak pull up inverter When the SYNC pin is pulled low either by the internal oscillator or an external clock the ramp cycle of the oscillator is terminated and forced 400 ns off time is initiated before a new oscillator cycle begins If the SYNC pins of several LM5118 IC s are connected together the IC with the highest internal clock frequency will pull all the connected SYNC pins low and terminate the oscillator ramp cycles of the other IC s The LM5118 with the highest programmed clock frequency will serve as the master and control the switching frequency of all the devices with lower oscillator frequencies SYNC 100 LA E be F La Q R DEADTIME ONE SHOT 30058519 FIGURE 8 Simplified Oscillator and Block Diagram with Sync I O Circuit www national com 8LLGNT LM5118 Error Amplifier and PWM Comparator The internal high gain error amplifier generates an error signal proportional to the difference between the regulated output voltage and an internal precision reference 1 23V The out put of the error amplifier is connected to the COMP pin Loop compensation components typically a type II network illus trated in Figure 1 are connected between the COMP and FB pins This network creates a low frequency pole a zero and a noise reducing high frequency pole The PWM comparator compares the emulated current sense signal from the RAMP g
32. is dependent on the terrain climate ability and endurance of the survivors Regardless of the situation it is to be assumed that all of the survivors are incapacitated and require assistance as soon as possible When the location of the survivors is unknown a well developed search plan is pivotal to the success of the mission The first step to making a search plan is to first evaluate the situation taking into account elements such as the intended route of the victim their last known position any hazards along the path of travel the experience level of the victim the current and near future conditions of the search environment and the results of any previous searching The second step is to estimate the distress incident location The distress incident location is estimated by taking the information gathered about the victim from the first step and using it to determine the greatest distance the victim could have traveled from their last known position Once they have an estimated location the next step is to determine the best way to use the available search personnel to obtain success This is a critical step as this will determine the rescue teams starting location and where they will concentrate their search path Once the plan has been determined it is administered to the rescue team and executed Joint Chiefs of Staff 1991 For initial searches the higher amount of resources available the greater the success of the mission and the so
33. lt Sets if the horizontal is aligned with the wings or at a 45 degree angle gt lt define name HORIZ SENSOR ALIGNED value 0 gt lt Defines the signs for the different differential pairs gt lt define name IR1 SIGN value 1 gt Ades Polens lt define name IR2 SIGN value 1 gt Lre PECI lt define name TOP SIGN value 1 gt lt Sets the roll and pitch neutrals Roll is calibrated to prevent turning and the Pitch is calibrated to keep the UAV at a constant altitude while under throttle gt lt define name ROLL NEUTRAL DEFAULT value 0 unit deg gt lt define name PITCH NEUTRAL DEFAULT value 0 unit deg gt lt define name CORRECTION UP value 1 gt lt define name CORRECTION DOWN value 1 gt lt define name CORRECTION LEFT value 1 gt lt define name CORRECTION RIGHT value 1 gt lt section gt Figure 62 The thermopile section within the airframe configuration file This is where neutrals signs and other parameters are configured Thermopile Calibration Our first step to calibrating the thermopile was to find the neutral values of the IR differential pairs since thermopiles have varying neutral values due to the fabrication process The IR sensors were placed within a foam box and clamped shut to isolate the sensors from any IR noise within the room Within the foam box the IR sensors should register no IR readings so the value observed within the messages wind
34. modification of the receiver MeekPE boards are currently available at batchpcb at the following link http batchpcb com index php Products 43035 and the bill of materials is listed at the following site http oaparazzi enac fr wiki MeekPE PPM Encoder Board Measuring the Radio Receiver and PPM Signal l Bind the radio controller to the radio s receiver instructions depend on the system and make sure all of the trims on the radio are zero The servo commands are not transmitted at the same time by the radio and come in sequentially By connecting two oscilloscope probes to two of the servo channels on the receiver you should be able to tell that one comes after the other Use as many oscilloscope probes available to determine the last channel transmitted to the receiver The last servo channel is what is connected to the last servo connector on the MeekPE board Connect the oscilloscope probe one of the servo channels make sure you ground the oscilloscope probe to the receiver 4 Measure the neutral servo value for the corresponding control surface Tek aie Trig d M Pos 0000s CURSOR Type Source ot 15 60ms az 4 10Hz ey gigy JAIGI Cursor 2 15 6ms 0 0g CH2 200 M S 00rns CH2 360m Reta 1 00 S00us 63 0449Hz Neutral PWM Measurement Measure the minimum and maximum for the corresponding control surface Notate the values along with the servo channel These values will be used by the au
35. printer Once it was printed the image was transferred onto the copper using a hot clothes iron then etched away the rest of the material using an etching solution The problems with doing this method were that the circuit used very small pitch components which couldn t be transferred with a high enough resolution image to the board Unfortunately a mistake was made and the image was not mirrored before being ironed onto the copper At that point we decide to scrap the printed circuit board and just made our own using standard through hole component from the ECE shop and a prototype board This proved to be successful and allowed the team to continue work with the autopilot system 58 Following the steps described in Appendix G User Manual Radio Control Interface it can be determined which servo channel is transmitted last This last servo is wired to the Last Srv via on the encoder board Figure 68 is a block diagram demonstrating our wiring from the radio receiver to the MeekPe encoder board and then the block diagram of the MeekPe encoder board MeekPe PPM Encoder Servo Channel 5 KA High Pass Positive Filter Rectifier Send Channel j High Pass Positive Filter Rectifier Seni Channel P HH High Pass Positive Filter Rectifier RIC Sr PPM Signal Receiver Der Channel D High Pass Positive Filter Rectifier Serve Lhannel S High Pass Positive Filter Rectifier Lasi Servo Charge o High Pass Positive Filter
36. robot this communication needs to be at an absolute minimum which makes this role of the ground controller very important Acceptable communications include comments about visible hardware malfunctions like broken landing gear or visible smoke etc The Safety Positions for Multiple Simultaneous Robot Testing Testing multiple robots at once will be a difficult task Much more communication and organization is necessary to make the test successful therefore there are a few additional safety positions for just such circumstances 1 The Chief Flight Controller The chief flight controller is a flight controller and has all of the responsibilities of a flight controller as specified above In addition to everything stated above the Chief flight controller is responsible for A Holding a flight controllers meeting before the robots are even brought out onto the field At these meetings the chief flight controller is to review any maneuvers to be undertaken by the test that day He or she needs to determine what exactly the robots will be doing and when See Explanation of Flight Plans for details B Coordinating multiple robots in the air and on the ground by communicating with the other flight controllers for each robot in the test 2 The Ground Controller The ground controller takes the same role as when there is only one robot being operated He or She is still second in the safety hierarchy All responsibilities are the same
37. s dev ttyUSBO wine dosdevice com10 Now when you connect the Xbee to the computer Wine will set up COM 10 as the xbee Using X CTU With X CTU set up to run on Linux the next step is to update the firmware on the Xbee radios All Xbee radios that are in use must be updated Below 1s a basic diagram of the different Xbee radios used with Paparazzi 119 Computer Running GCS Coordinator Xbee End Device End Device End Device Xbee Xbee Xbee Autopilot 1 Autopilot 2 Autopilot 3 Updating the firmware Note Keep track of which xbee radio is the coordinator and which are the end devices If they are not marked they are easy to lose track of them when updating 1 Place the Coordinator Xbee radio in the usb connector and then plug in the usb into the computer 2 Execute X CTU with Wine 3 Select the user comports tab and then add comport 10 P Ki X CTU Wi n About PC Settings Range Test Terminal Modem Configuration Com Port Setup Select Com Port Data Bits 8 z Parity NONE z Stop Bits fi El Test Query Host Setup User Com Ports Network Interface User defined com ports 8 User COM10 Add User Com Port Com Port Number Add Delete User Com Port Delete 120 4 Make the comport active by clicking it within Select Comport Window and then set the baud rate to 57600 Note if the Xbee radio is new the default baud rate may be different
38. same console 8 1 Recommendations for Future Development In the future this project needs to install the autopilot in Jay and successfully make AUTO 1 and AUTO 2 flights ensuring that it can successfully navigate two or more preprogrammed waypoints Duck needs to be finished and tested from start to finish Robin needs the most amount of work due to the crash which involves a new airframe Once all of the UAVs are successfully flying under autopilot the next step would be to integrate completely with the other teams Integration with the other projects would allow the users to fly the fleet of drones from the Microsoft Surface update waypoints and stream filtered images back from the different UAVs To accomplish this the software team needs to have an interface with the autopilot board in order to change waypoints as well as get current telemetry and location data This process has been started but an elegant solution has not been developed yet Mechanically the teams need to integrate all of the necessary hardware for each team into the UAVs including the search and rescue cameras FPGA board for image processing the wifi modules the power distribution boards and the software team s logic board All of these components need to be mounted in the UAVs with a vibration resistant mounting system and wired together The layout inside the UAVs has been complete for all of these components with the help of CAD models of the airframes to ensure
39. same time interval each cycle The inductor current ramps up propor tional to VIN when Q1 and Q2 are active and ramps down www national com 10 through the re circulating diode during the off time The first order buck boost transfer function is VOUT VIN D 1 D where D is the duty cycle of Q1 and Q2 HO HS LM5118 Buck Switch Current 30058512 100 o CH DUTY CYCLE 30058513 FIGURE 4 Mode Dependence on Duty Cycle VOUT 12V Operation Modes Figure 4 illustrates how duty cycle affects the operational mode and is useful for reference in the following discussions Initially only the buck switch is active and the buck duty cycle increases to maintain output regulation as VIN decreases When VIN is approximately equal to 15 5V the boost switch begins to operate with a low duty cycle If VIN continues to fall the boost switch duty cycle increases and the buck switch duty cycle decreases until they become equal at VIN 13 2V Buck Mode Operation VIN gt VOUT The LM5118 buck boost regulator operates as a conventional buck regulator with emulated current mode control while VIN is greater than VOUT and the buck mode duty cycle is less than 75 In buck mode the LO gate drive output to the boost switch remains low 11 Buck Boost Mode Operation VIN VOUT When VIN decreases relative to VOUT the duty cycle of the buck switch will increase to maintain regulation Once the duty cycle
40. signal representing or emulating the inductor current The emulated ramp provides signal to the PWM comparator that is free of leading edge spikes and measurement or filtering delays The current reconstruction is comprised of two elements a sam ple and hold pedestal level and a ramp capacitor which is charged by a controlled current source Refer to Figure 9 for details The sample and hold pedestal level is derived from a mea surement of the re circulating current through a current sense resistor in series with the re circulating diode of the buck reg ulator stage A small value current sensing resistor is required between the re circulating diode anode and ground The CS www national com 14 and CSG pins should be Kelvin connected directly to the sense resistor The voltage level across the sense resistor is sampled and held just prior to the onset of the next conduction interval of the buck switch The current sensing and sample and hold provide the DC level of the reconstructed current signal The sample and hold of the re circulating diode current is valid for both buck and buck boost modes The positive slope inductor current ramp is emulated by an external ca pacitor connected from the RAMP pin to the AGND and an internal voltage controlled current source In buck mode the ramp current source that emulates the inductor current is a function of the VIN and VOUT voltages per the following equation 5 uA Irkamp buck 7
41. signal for output voltages less than or equal to 12V For higher output voltages additional slope compen sation may be required In such applications the ramp ca pacitor can be decreased from the nominal calculated value to increase the ramp slope compensation The pedestal current sample is obtained from the current sense resistor Rs connected to the CS and CSG pins It is sometimes helpful to adjust the internal current sense ampli fier gain A to a lower value in order to obtain the higher current limit threshold Adding a pair of external resistors RG in a series with CS and CSG as shown in Figure 10 reduces the current sense amplifier gain A according to the following equation __10k 1k Rg CURRENT LIMIT COMPARATOR Vth RAMP RAMP RESET I TRACK and HOLD 10k 1k CS Current Limit In the buck mode the average inductor current is equal to the output current lout In buck boost mode the average induc tor current is approximately equal to VOUT VIN lout x 1 Consequently the inductor current in buck boost mode is much larger especially when VOUT is large relative to VIN The LM5118 provides a current monitoring scheme to protect the circuit from possible over current conditions When set correctly the emulated current sense signal is proportional to the buck switch current with a scale factor determined by the current sense resistor The emulated ramp signal is applied to the current limit comparato
42. system used for the airframes we selected was called Paparazzi Paparazzi is an open sourced Linux based control system designed to autonomously fly fixed winged airplanes and quad copters For this project we will be implementing the autopilot system into our airframes with the goal of GPS waypoint navigation This system is required to have the ability receive new waypoints from the software integration team which is responsible for controlling the UAVs to follow a dynamic search and rescue navigation routine The autopilot system features three distinct modes manual mode Autol and Auto2 Manual mode is a direct control of the UAV via a radio controller Auto 1 is a partial stabilization mode which allows the user to configure which control surfaces the autopilot has control over to stabilize the plane to fly in a straight line Auto 2 is a full autonomous mode which follows a flight plan that contains preconfigured flight blocks Paparazzi provides a ground control station which allows the user to view the UAV s approximate orientation speed altitude and pitch based on configured sensors The team successfully configured a GPS module for position of the UAV and IR thermopiles for flight stabilization The sensor data is transmitted wirelessly using Xbee radios from the UAV back to the ground control station for data recording and live feedback to the user 7 CONTROLS SIMULATION The ground control station provides the ability to ru
43. t demand the close tolerances that other materials do Considering the size and weight of the aircraft the project calls for balsa wood is a good choice Balsa wood is light readily available and cost efficient Usually when constructing a wooden frame the basic shape and airfoils are designed then modeled by a ribbed structure that will support the covering in the desired shape These rips can be cut out by hand or using a laser cutter then attached together using some type of epoxy or wood glue Once the frame is assembled it can then be covered in cloth plastic or more wood For full scale aircrafts like personal airplanes fabric made from high grade polyester is usually used to cover the frame However for small crafts like UAVs and RC airplanes fabric is simply too heavy for the amount of durability it provides For lighter planes a plastic covering called MonoKote is often used to cover the frame Heat is applied to shrink it and seal it around the structure For aircrafts that need a more durable covering lightwood is sometimes used to cover the structure Wet wood is malleable enough to be warped around the frame while keeping its hardness when re dried While wooden frames are easier to build and many times more cost effective they are not nearly as durable or reliable as other materials Foam Foam is commonly used in small aircraft construction Smith 2006 Foam is a very ridged and compression resistant material for its weight It is
44. that each airframe remains balanced with the addition of all the extra weight Once these have been complete the system will be fully functional and ready to perform low altitude efficient aerial search and rescue 90 9 Acknowledgments The platform team of project wind would like to give thanks to the following people and organizations e Professor Padir e Professor Wyglinski e Professor Looft e Professor Stafford e Professor Hall e Mr Richard Gammond e Tanner Hiller Airport e The Mathworks e WPI Robotics Department e WPI ECE Department e Joseph Funk Sr e Project wind software team e Project wind communications team 91 92 10 Authorship Introduction Written by Christopher Whipple Joseph Funk Platform Development Written by Catherine Coleman Joseph Funk UAV Control Design Written by James Salvati Timeline Written by Christopher Whipple Budget Written by Christopher Whipple Integration with software and communication Written by James Salvati Results Written by Catherine Coleman James Salvati Christopher Whipple Joseph Funk Conclusion and Recommendations Written by Christopher Whipple oS SS En a Appendix A Written by Christopher Whipple Appendix B Written by Christopher Whipple Appendix E Written by Catherine Coleman James Salvati Christopher Whipple Joseph Funk Appendix F Written by Catherine Coleman Joseph Funk Appendix G Written by James Salvati Appendix H Written by
45. the planes bank angle 71 v CH throttle setpoint h_ctlaileron_of_throttle bh ctl aileron_ setpoint h_ctl_roll_setpoint lt 7 ry Ka err we 9600 9600 estimator_deltaphi bh cp roll rate gain estimator Dh Figure 87 Roll Control Loop The roll control loop sets the target position for the ailerons the control surface with a direct effect on the roll of the plane The estimator_phi value is the current phi otherwise known as bank angle in this case is the feedback for the system A gain for the roll rate can be defined which is contained in estimator_deltaphi and a gain based on the current throttle set point so thata relationship between the throttle and the roll set point can be made For our navigation simulation the roll_attitude_gain was changed within the roll control loop to examine its effect on waypoint navigation Waypoint Update Changed Roll Kp Meters 20000 150 100 50 0 50 100 150 200 Meters Figure 88 Waypoint Navigation Simulation The simulated plane was launched and then circled the standby waypoint As soon as the plane was on the far side of the standby waypoint relative to the next waypoint the command to circle the target waypoint was issued The first simulation was started with a kp of 7400 which was the current 72 default value for the airframe As the kp was increased from 7400 to 3400 minor oscillations can be seen when the waypoint was changed but the oscillations settl
46. the LM5118 is as follows Rioap X Vin DC Ga e TEEN 10Rs Vin 2Vour The dominant low frequency pole of the modulator is deter mined by the load resistance R gap and output capacitance Cour The corner frequency of this pole is i 8 1 Duin TH Ze x Bi cap X Cour For this example Ri oap 42 Dyn 0 294 and Cour 454 UF therefore Additionally there is a right half plane RHP zero associated with the modulator The frequency of the RHP zero is Rroap 1 DI fRHPzero 7 8 kHz The output capacitor ESR produces a zero given by 1 ESR er a 27 X ESR x Cour The RHP zero complicates compensation The best design approach is to reduce the loop gain to cross zero at about 30 of the calculated RHP zero frequency The Type Il error amplifier compensation provided by R4 C18 and C17 places one pole at the origin for high DC gain The 2nd pole should www national com SLLSIN LM5118 be located close to the RHP zero The error amplifier zero see below should be placed near the dominate modulator pole This is a good starting point for compensation Refer to the on line LM5118 Quick Start calculator for ready to use equations and more details Components R4 and C18 configure the error amplifier as a type II configuration which has a DC pole and a zero at 1 P S xnxR4xC18 C17 introduces an additional pole used to cancel high fre quency switching noise The error
47. the other flight systems for any extended period of time This allowed the teams to develop each portion of the project separately while still allowing for integration questions to arise and be answered accordingly This also allowed each project to move at its own pace without fear of interfering with the other projects As such there was never a set timeframe to perform the integration within the scope of the individual projects The plan was to have each team finish their projects separately in C term keeping integration in mind as the projects progressed through the year and then after the projects were submitted the teams would convene and actually put all of the parts together in D term and do full system testing This due to the same setbacks as stated for the hardware team in particular held the integration up as well To see the actual steps towards integration see section 6 5 Budget Project WiND was sponsored primarily by WPI and The Mathworks The Mathworks donated 3 000 to all of project WiND some of which was used on this project specifically The final budget for all of the components used in this project is 2 770 94 the breakdown for which is located in Appendix E This total is just a reflection of the purchases actually made These purchases were decided based on necessity at the time of the purchase For example line item number 21 in the budget in the Appendix E is a DX6i radio system of which only 1 is listed as being pu
48. to make a slower approach during landings For some RC aircraft the ailerons can be used as flaps when properly configured in the transmitter or on board autopilot Lay it Out The next step is to start drawing reference lines on paper and lay out the general location of things to achieve the correct proportions and moments The fuselage length should be around 75 of the wingspans The nose length should be around 20 of the fuselage length The horizontal tail surface area should be around 25 30 of the wing area The vertical tail should be around 35 of the stabilizer area Johnson 2007 Figure 12 illustrates a plane with the ideal ratios Next it is recommended to use a computer aided design CAD program to model all of the components and balance the airplane This CAD model should be an accurate representation of the final product 11 1 500 To 0 800 10 00 Figure 12 Lay out of a plane using the recommended ratios based on a 10 unit wing span Construction Techniques There are several different materials and techniques commonly used for building homemade aircrafts Each of these methods have their own unique advantages and disadvantages and targeted application The most common building materials are wood fabric plastic metal foam and composites Balsa Wood The advantages of working with a wood frame are that it requires only simple tools for construction and are fairly inexpensive to build They also don
49. waypoints Configuring Plane Airframe Selection To add a new airplane to the selectable list 1 Open paparazzi conf conf xml 2 Add an additional aircraft to the list of aircraft changing the following e Name New name for your aircraft e Ac ID A new id number for your plane must be different from the others e Airframe default airframe file e Radio default radio configuration file e Telemetry default telemetry configuration file e Flight_Plan default flight plan file e Settings default settings file Configuring Connection and GCS To add or modify a new connection setting 1 Open paparazzi conf control_panel xml 2 Find the sessions section 3 Each session contains different ground station programs the required ones are 122 e Data Link The data link connects to the autopilot Typical flags used are lt arg flag d constant dev ttyUSBO gt location of the device to be connected to lt arg flag transport constant xbee gt type of protocol for communications lt arg flag s constant 57600 gt baudrate e Server Used to continuously record the messages received from the autopilot They are stored in paparazzi var e GCS The ground control station Provides a user interface to the autopilot system e Messages Provides a user interface to reading incoming messages from the autopilot Useful for debugging Multi plane Simulation To perform a multi plane simulation Select the
50. where applicable In general we need to keep the robots less than 400 feet off the ground Speed should not be an issue due to our heavy payload and intentionally slow propeller selection See Appendix D for more information from AMA and their rules and regulations 3 Transportation of the Robot 104 Due to the nature of the project it is inevitable that the robots will have to be transported from the build facility to a safe place to fly See description of flight plans and definition of Hot Zone for details When transporting the robot follow these guidelines to ensure the safety of the WiND personnel as well as the safety of the robot A No fuel or batteries are to be in on or around the robot during transportation B Fuel will be carried in a gasoline safe container in a different vehicle from the robot The container is to be both DOT and UL certified and is to never be less than half full and never more than 95 full to allow for expansion C The robot is required to fit entirely into the vehicle in which it is to be transported For example strapping the robot to the top of a passenger car is unacceptable as is having the robot hang off the back of a pickup truck D The robot depending on size may need to be transported in several pieces and rebuilt in the hot zone of the test site 4 Liability Forms Any and all team WiND personnel advisors and any spectators that will be present for a project WIND test flight
51. which 66 contains an estimation of the planes position and orientation based on available sensors This acts as the feedback term for this system Nav_pitch is the input to the control loop overseeing the target set point for the elevator as the elevator is the main control surface for controlling the planes pitch The elevators control loop is illustrated in Figure 80 nav pitch Bounds ctl pitch kd ctl pitch kp Ka i 96000 9600 Estimator phi Estimator theta Figure 80 Elevator Position Control Loop Shown in figure 80 the input to the elevator position control loop is nav_pitch the output of the pitch control loop The output is the target elevator position The feedback of the system is the estimator s phi and theta value which represent the current orientation of the plane For our pitch simulations the team modified clt_auto_pitch_kp and clt_auto_pitch_kd which was part of the pitch control loop The control constants are defined within the airframe configuration file and were modified before each simulation The simulation started with the plane on the ground and then issued a command to take off The first simulation was ran with the default settings for the configuration file with a kp of 20000 kd of 0 and a ki of 0 25 Figure 82 was captured from the end of one of the launch simulation 67 10 18 58 TelemasterTest Geo ir 10 18 58 TelemasterTest AUTO Flight Plan GPS PFD Misc Settings Oj R
52. will mot be Gran a In a Careless of recess manner ID Ata locaton where model aircraft ac 2 Model aircraft pilots wilt a Yield the nght of way t all man carrying arcraft ID See and avoid all aircraft and a Spotier musi be used when apomonate AMA Document 540 0 See and Avoid Guidance IC Nod fy higher han approximately 400 feel above ground level within three 3 miles of an airport without motfying the airport operator og Noi priere with operations and trafic pattems at amy airport heliport or seaplane base except where there is a miked use agreemeni Tei Nol exceed a lakeodt weight including fuel of 55 pounds unless in compliance with he AMA Large Model Aircraft program AMA Document 520 A ID Ensure the aircraft is identified with the name and address or AMA number of the owner on the inside or affixed to ihe outside of fhe model aura This does not apply to model aircrafl Bowen indoors ig Nol operate aircraft with metatblade propellers or with gaseous boosts except gor helicopters operaied under the provisions of AMA Document 555 h Noi operate model aircraft while under the infwence of alcohol or while using any drug which could adversely affect the pilot s ability to safely contol fhe model Creates a hazard to persons of property e Free Fight fuses of dewices thal bum producing smoke and are securely attached to the model aircrafl during fight e Rocket motors using sold propeliant up to a G series site may be used pro
53. 0 If Flight USB XBee API 57600 is not an option it can be added to your control panel with the following lines lt session name Flight USB XBee API 57600 gt lt program name Data Link gt lt arg flag d constant dev ttyUSBO gt 121 lt arg flag transport constant xbee gt lt arg flag s constant 57600 gt lt program gt lt program name Server gt lt program name GCS gt lt program name Messages gt lt session gt To use multiple planes connect to the first plane then go back and select your second plane and then connect using the same method Ground control station The ground control station GCS provides the visual feedback of the UAV A detailed explanation of it can be found at the paparazzi wiki located here http paparazzi enac fr wiki GCS A key feature to note is the settings tab This allows the user to update of values defined in the airframe configuration file during runtime This is important for modifying the control characteristics of the UAV and any neutrals of the sensors during flight The flight plan loaded is dependent on the flight plan configuration file The home way point can be defined at the top of the configuration file and when you load the GCS the home way point will be located there By going to the tool bar at the top of the GCS and then selecting maps you can select the source of the map default is google and then load the tile corresponding to your
54. 0 771 Tel 1 800 272 9959 English Tel 44 0 870 850 4288 www national com
55. 040 average 0 gt lt channel ctl GEAR function MODE min 1100 neutral 1760 max 2060 average 0 gt lt channel ctl RUD function YAW min 2260 neutral 2660 max 3080 average 0 gt 126 lt channel ctl THRO function THROTTLE min 1100 neutral 1520 max 2020 average 0 gt lt radio gt The order here matters It is the order that the channels are within the PPM If this is setup wrong some control surfaces may not work or will be swapped Configuring Control Surfaces Now that the radio configuration file is set up the next step is to define the control surfaces within the airframe configuration file Servo Definition e First you define the servos and their names lt servos gt lt define the servo ports and their min neutral max values gt lt servo name MOTOR no 0 min 1000 neutral 1440 max 1960 gt lt servo name AILEVON_ LEFT no 1 min 1000 neutral 1500 max 2000 gt lt servo name RUDDER no 2 min 1040 neutral 1440 max 1840 gt lt servo name AILEVON_RIGHT no 3 min 1000 neutral 1500 max 2000 gt lt servo name ELEVATOR no 4 min 1880 neutral 1440 max 1040 gt lt servos gt e The servo name is the object name for that servo referenced later e The no number sets which servo output the channel will be outputted on e The min neutral max values are the numbers measured from the output of the receiver e To fli
56. 1 Figure 53 Ardupilot is an open source autopilot solution featuring arduinos 3 1 1 3 Paparazzi Paparazzi is an open source Linux project The project includes software to run on open source hardware which is available assembled from vendors It will handle flying the plane and includes a ground base station for interfacing with the plane during flight The paparazzi autopilot is designed to run on ARM7 and STM32 family of processors 45 Hu GE E SX GE Ar ow GE aL Figure 54 Paparazzi autopilot system This particular version is named YAPAZ Paparazzi allows for the configuration of many different sensor combinations for use with flying New control loops can be adjusted or implemented based on user requirements The advantage of the paparazzi project is that it allows the user to create custom subsystems to support sensors not within the list of sensor firmware available for the autopilot Many autopilot research projects utilize the Paparazzi autopilot system Reuder et al 2009 Bronz et al January 2010 Jensen et al 2008 3 1 2 Flight sensors In order to determine the planes position orientation speed and other flight characteristics sensors are used to calculate and relay back this information to the ground station All of this information is required to provide the closed loop feedback for the control system directed by the autopilot software to keep the plane stabilized during flight The following sensors we
57. 140575 files emav09 optipilot web pdf Bin He Justice Amahah 2009 March The design of an unmanned aerial vehicle based on the ArduPilot Indian Journal of Science and Technology Vol 2 No 4 Available http www indjst org archive vol 2 issue 4 apr09justice pdf Bronz Murat Moschetta Jean Marc Brisset Pascal Gorraz Michel 2009 December Torwards a Long Endurance MAC International Journal of Micro Air Vehicles vol 1 nu 4 pp 241 254 online Available http multi science metapress com content qx60752m05k45439 C B Low A Trajectory Tracking Control Design for Fixed wing Unmaned Aerial Vehicles in 2010 IEEE Internal Conf on Control Applications Yokohama Chang Sun Yoo Iee Ki Ahn 2003 Oct Low cost GPS INS sensor fusion system for UAV navigation Digital Avionics Systems Conference 2003 DASC 03 The 22nd online vol 2 no pp 8 A 1 8 1 9 vol 2 12 16 doi 10 1109 DASC 2003 1245891 Available http ieeexplore ieee org stamp stamp jsp tp amp arnumber 1245891 amp isnumber 27920 96 Chao HaiYang Cao Vongt an Chen YangQuan 2010 February Autopilots for small unmanned aerial vehicles A survey International Journal of Control Automation and Systems online Vol 8 no 1 pp36 44 February 2010 DOI 10 1007 s12555 010 0105 z Available http www springerlink com content m2x11674184m208x Dobrokhodov V N Kaminer I I Jones K D Ghabcheloo R 2006 June Vision b
58. 2o gt lt message name WP MOVED period 0 5 gt lt message name CIRCLE period 1 05 gt lt message name DESTRED perioed 1 05 gt lt message name BAT period 1 1 gt Figure 64 Portion of the Telemetry configuration file This shows some of the available types of messages that can be sent across the xbee radios along with the rate in which they are transmitted Figure 64 shows some of the messages that are sent from the default telemetry file After testing the autopilot in the air unnecessary messages were removed from the default telemetry file Some important messages that were used were the PPM and the command messages The PPM message contains the last radio receiver packet and its values The command message contains the target position of the servos These two messages were key for determining how the radio encoder board operated See radio control for more details 56 Ime leGweotzie report amp ui wage Ce Ty 011011 ea Wiid ampi lie 261 ER uint Height bimp ier O its KR abo rette b 7 O T DES AED uinte stage Here a 0 D VALUE DOWNLINK DW PIK STATU P ENERGY ESfAaTOn FAY STATS GPS CP SCH R_S EPCS PONG PERZ MODE STATE_FRTER STaTut WP Bove nid energy meric 0 Figure 65 Above is an example of the messages window provided by the ground station to view incoming messages from the UAV The bat message is currently selected and shows values such as voltage and current fr
59. 3 1 2 2 GPS The global positioning system GPS utilizes satellites orbiting around the Earth to obtain a position A GPS receiver can be placed on the UAV to provide the position of the UAV during flight Knowing the UAV s position and time you can calculate the UAV s velocity The flight plan will contain waypoints relative to the starting GPS coordinate GPS modules are implemented on many different unmanned aerial research projects Am et al 2007 Abdelkrim et al 2008 Chang Sun et al 2003 47 3 1 2 3 Airspeed By default the speed of the plane is calculated from the GPS This works well in calm conditions but becomes inaccurate in windy conditions Using an airspeed sensor will improve the planes throttle control to keep a constant speed necessary for maintaining the location and altitude of the plane Airspeed sensors are used on many different unmanned aerial research projects Jung et al 2005 Beard et al 2005 Chao et al 2010 Beyeler et al 2009 3 1 2 4 Inertial Measurement Unit The inertial measurement unit IMU is a combination of accelerometers and gyroscopes used to determine the acceleration rate of the airplane and changes in roll yaw and pitch Using time internally maintained by the processor the velocity position and orientation of the aircraft can be calculated The IMU can be paired with some of the following sensors to compensate from possible accumulating errors In addition to combining with additiona
60. 8 WP_MOVED 0 268579 4684152 234 559998 19 94 043 8 DOWNLINK STATUS 94 32917 1471 0 469 20 17 28 94 103 6 FBW_ STATUS 2011260 94 111 6 NAVIGATION 21 3 4 0 25 00 94 1318 GPS 3 26653400 468411392 3153 160160 31 36 1662 252374500 19 1 Figure Above is a sample data file collected during tested The messages above were selected by the telemetry file and then recorded when received from the UAV 130 Radio The radio configuration file defines how the PPM message from a radio receiver is parsed into the autopilot system This setup process is further described under Measuring the Radio Receiver and PPM Signal Settings The settings configuration file allowed us to change values during flight time for numerous subsystems This expedited the testing process as it allowed us to change flight parameters from the ground as opposed to landing the UAV and uploading new changes between each flight Values defined in the settings file are shown in the settings tab within the ground station Flight Plan flight params control ir auto throttle auto pitch roll neutral 0 06203 mt Themen pitch neutral SAS ay 360 lat_corr Figure Settings Tab within Ground Station The configuration files only set values and define flags for the autopilot code which 1s all stored within paparazzi sw airborne 131 Appendix H Power board schematic LTT HIA a CA COM CR d fa K D KIR Ao DR IVS 121E Sr
61. B DC Bias current EI 291 2s 260 ma a O a rh EN INPUT EN mput Bias Curent EN Ja i ENInputBias Current venzosv a lai a EN InputBias Curent venz m UVLO THRESHOLDS UVLO Standby Tube Juvtonsing Lg 1 231 an V UVLOThreshold Hysteresis o J Jows fy UVLO Pulkup Current Source uvozov Ts UVLO PulkdownFosow OOO O oe SOFT START SS Current Source SS ON UA SS to FB Offset FB 1 23V Jo m SS Output Low Voltage Sinking 100 pA UVLO DN 7 m FB Reference Voltage Measured at FB pin 1 230 V FB COMP FB 2V0 2V nA ERROR AMPLIFIER VREF FB ER Input Bias Current Bias ER Input Bias Current www national com 4 mA PWM COMPARATORS COMP to Comparator feet o o OSCILLATOR RT PIN lene Frequency 1 RT 29 11 KQ 178 200 224 iene Frequency 2 RT 9 525 kQ 450 515 575 CURRENT LIMIT Noam Cycle by cycle Sense Voltage RAMP 0 Buck Mode 125 147 Threshold CS CSG Noam Cycle by cycle Sense Voltage RAMP 0 Buck Boost Mode 255 mV Threshold CS CSG S EE E RAMP GENERATOR vout Bascu vourz s LOW SIDE LO GATE DRIVER VoLL LO Low state Output Voltage lLo 100 mA 0 095 0 14 0 23 V VoHL LO High state Output Voltage lo 100 mA Hl Ged Vout Veo Vio LORiseTime Jegen e Is Lo Fatime Jegen u Im HIGH SIDE HO GATE DRIVER VoLH HO Low state Output Voltage lho 100 mA oi 0 135 0 21 V VoHH HO High state Output
62. C Settings 10 18 58 TelemasterTest mayd Gen 10 19 07 TelemasterTest Holdin gt block Wait GPS 10 23 10 TelemasterTest Takeo 10 23 33 TelemasterTest Stand SE BERS Standby EE BE ston Time 01 11 Stage 01 11 K ETA N A Mark L Ha k Target Alt im 76m 75m en wi N amp O Loiter Cruise Dash o gt block Geo init gt block Holding point Standby Figure 81 Screen capture of the ground control station during a launch simulation The launch simulation involved starting the plane at the home position After launching the plane the target position is set and climbs in altitude until it hits 25 meters Once the plane hits 25 meters the plane enters the standby navigation routine where the plane sets the target altitude to 75 meters and then circles the standby coordinate with a radius of 80 meters 68 Takeoff Pitch_Kd 0 Altitude Meters Pitch_Kp 20000 Pitch_Kp 10000 Pitch_Kp 5000 Target Altitude 60 80 Time s Figure 82 Pitch Launch Simulation where Kd 0 This graph shows three different simulations where the kd constant was Kept at 0 and then the kp constant was varied as represented in the graph Key The altitude of the plane during the simulation was recorded within the GPS messages A python script was used to parse the data for GPS and Altitude and then the data was plotted as shown above After takeoff the plane navig
63. Cand W S WS 0 H 2 a D 3 DU Tt H H w D z 13 u B Le 17 D la 5 Inder Schematic 1 Power board control logic 132 Schematic 2 Regulator circuit for autopilot 133 Schematic 3 Regulator circuit for camera 134 45Vde 10A FPGA Schematic 4 regulator circuit for FPGA 135 5 Vide 10A Panda Schematic 5 regulator circuit for Panda board 136 Schematic 6 Regulator for radio support hardware 137 Schematic 7 regulator for the USRP2 SDR radio 138 Schematic 8 Independent regulator for servos 139 Schematic 9 Regulator for the WiFi modules 140 Appendix l LM5118 Data Sheet 141 April 30 2008 National Semiconductor LM5118 Wide Voltage Range Buck Boost Controller General Description Features The LM5118 wide voltage range Buck Boost switching regu lator controller features all of the functions necessary to im plement a high performance cost efficient Buck Boost regulator using a minimum of external components The Buck Boost topology maintains output voltage regulation when the input voltage is either less than or greater than the output voltage making it especially suitable for automotive applications The LM5118 operates as a buck regulator while the input voltage is sufficiently greater than the regulated out put voltage and gradually transitions to the buck boost mode as the input voltage approaches the output This dual mode appro
64. Data is streamed to the mothership from the ground station the changes to the path are calculated the most efficient path is selected and then the path is dictated to the other drones in the network All UAVs carry search and rescue sensors and are autonomously controlled by the same autopilot system with the same sensors 1 5 Design Specifications To accomplish this mission several design specifications were established based on existing research and the needs of the other teams working on this project The list of design specifications included e Three fully autonomous aircraft e Interface with the UAV controlling search algorithm e Autonomous navigation based on GPS waypoint navigation The aircraft will need to be able to receive GPS coordinates from the search algorithm and then proceed to fly to the given coordinate then circle waiting for new GPS waypoints e Each UAV will need to carry a payload of 10 lbs in order to carry all of the processors cameras flight sensors and gimbal e Capable of flying at a cruising speed of 35 45 miles per hour under full load of search and rescue sensors e Capable of flying between 120 ft and 400 ft of altitude as specified by the FAA for UAVs e Capable of maintaining flight without refueling for a minimum ofan hour e Capable of supplying 100 watts of power to on board electronics for a minimum 1 hour per charge e Contains a pan tilts camera gimbal capable of holding up to two cameras
65. EE 37 31 TeilemasterTest Hokin 2227 3 TelemasterTest e stoge 13 10 222132 TelemasterTest Takeot Stage 14 04 ie ri Params mode ir attitude gute throtthe autu pi 2229 33 TelemasterTest Standt ETA NJA ions params mode lir attitude auto thvottie ae pp 72 79 33 tolomastertest stand en wa t params mode ir attitude ode throttle auto_pit E ok Gemen singi 0 000 pois 9 0000 F Mark pgn O d Mark RB poain o 9000 RAP i Alt e 0 611 0 611 Torget Ak rol 0 6108 b 46m 50m rot 0 6108 Se v ste Stm S0m rg 0 6108 0 611 F e Cube rem 19500 19509 000 d Lote Dah ogan 19500 dlli N DN O Lotter Cruise Dash n t9500 19500 000 d 4 drin A 0 000 tate 8 0 000 i i con d Figure 99 Waypoint Insertion Simulation This sequence of images demonstrates the insertion of the software team s navigation routine into a paparazzi simulation Figure 99 shows the update of the target waypoint in this case the standby waypoint based on the output waypoints from the software integration team s navigation routine Each image is taken upon assigning the next waypoint where the time of the simulation can be viewed in the panel on the bottom left corner of each image From viewing the images left to right path represents a spiral of circles around the center waypoint This circling routine provides camera coverage over the target waypoint cell Upon completion of the final design the software integration component would have direct
66. FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS PRIOR WRITTEN APPROVAL OF THE CHIEF EXECUTIVE OFFICER AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION As used herein Life support devices or systems are devices which a are intended for surgical implant into the body or b Support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected to result in a significant injury to the user A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system or to affect its safety or effectiveness National Semiconductor and the National Semiconductor logo are registered trademarks of National Semiconductor Corporation All other brand or product names may be trademarks or registered trademarks of their respective holders Copyright 2008 National Semiconductor Corporation For the most current product information visit us at www national com National Semiconductor National Semiconductor Europe National Semiconductor Asia National Semiconductor Japan Americas Technical Technical Support Center Pacific Technical Support Center Technical Support Center Support Center Email europe support nsc com Email ap support nsc com Email jon feedback nsc com Email support nsc com German Tel 49 0 180 501
67. Flight The undersigned participant does release and shall indemnify and hold harmless WPI its officers trustees employees and agents from and against all claims damages losses and expenses including but not limited to medical expenses attorneys fees and court awards arising out of or resulting from any injury sickness disease or death occurring in connection with my participation in the prject WIND test flight Signature of this form verifies that the participant understands and confirms that he she is volunteering to participate in the aforementioned activity at his her own risk Signature of this form verifies that the participant is aware of and understands the potential inherent dangers and risks involved in participating in this activity Signature of this form also verifies that the participant is covered by appropriate medical insurance for injuries or illnesses and further understands that any deductible co payments and uncovered claims will be the sole responsibility of the participant This Liability Release shall be governed by Massachusetts law Participant s Signature Date 109 Appendix D AMA Regulations and Documents Academy of Model Aeronautics National Model Aircraft Safety Code Effective January 1 2011 A GENERALA model aircraal i a non human carrying aigat capable of sustained fight in the atmosphere It may mot exceed imitations of this code and is rules specific to the fying site 1 Model aircraft
68. Joseph Funk 93 11 Bibliography Search and Rescue National Search and Rescue Manual Volume 1 National Search and Rescue System United States Joint Chiefs of Staff Washington Dc 1991 http www towage salvage com files sar01 Heggie Travis W Amundson Micheal E Dead Men Walking Search and Rescue in US National Parks Wilderness amp Environmental Medicine vol 20 3 pp 244 249 2009 lserson K V Injuries to Search and Rescue Volunteers A 30 year Experience The Western journal of medicine vol 151 Iss 3 pp 352 353 09 1989 UAV Current Uses Air Force Public Affairs January 5 2012 MQ 9 Reaper Fact Sheet online Available http www af mil information factsheets factsheet asp fsID 6405 Bolkcom Christopher Homeland Security Unmanned Aerial Vehicles and Border Surveillance Congressional Research Service 12 2004 El Paso County Search and Rescue 2011 online Available http www epcsar org Eric Schmitt January 10 2012 3 killed as Drone Strikes Resume in Pakistan New York Times online Available http www nytimes com 2012 01 11 world asia cia drone strikes resume in pakistan html r 1 Michael A Goodrich Bryan S Morse Damon Gerhardt Joseph L Cooper Morgan Quigley Julie A Adams Curtis Humphrey Supporting wilderness search and rescue using a camera equipped mini UAV Journal of Field Robotics Vol 25 Iss 1 2 pg 89 110 2008 Rus
69. Once the major components of the autopilot system were confirmed working within the lab we then proceeded to an AMA certified airfield or private airport for the autopilot assisted flight Autopilot assisted Flight At the test field we will confirmed and tuned each of the major components of the autopilot before the flight This procedure was the same within the lab with additional steps for the following components e GPS o Should be able to obtain a GPS fix and the messages window should display correct coordinates from the GPS e IR Themopiles 76 o Before each flight the IR Thermopiles must be recalibrated as the level of infrared radiation is never constant between different days The thermopiles will be calibrated based on the process discussed in the infrared configuration section e Autol o The UAV should react as anticipated to being lifted and rolled based on IR Thermopile readings correctly as the thermopiles are now calibrated to the airfield For our first autopilot assisted flight we set the autopilot into Manual mode for a manual takeoff Once there was a clear path for flying straight and safely away from the team we engaged Auto1 The plane was expected to fly in a straight line Flight parameters were adjusted based on visual results The settings window was used to adjust values for the IR thermopiles and any of the neutrals for roll pitch and throttle to obtain a stable flight In the event the UAV became unstable t
70. P HED Lor L2Ze e E PPM O Oy 05 904 00 NAVIGATION O 20s Os Ot 66x EE 0 O OO NAVIGATION 0 2 0 0 86 1 0 0 DOWNLINK STATUS 28 16960 642 0 796 31 4981 75 DOWNLINK STATUS 28 16328 625 0 681 26 4977 88 RC 0 0 0 0 0 0 RC 0 0 0 0 0 0 STATE FILTER STATUS 3 391 ATTITUDE 0 77941 0 0 274627 COMMANDS 0 762 9600 0 COMMANDS 0 779 3334 0 ESTIMATOR 0 0 ESTIMATOR 0 0 NAVIGATION 0 2 0 E Gre 0 10 0 600 EE E Er 8 GPsSo000000000 FBW STATUS 2 0 1 104 0 WP MOVED 3 736327 6875 4693233 5 235 18 NAVIGATION REF 736276 4693252 18 WP MOVED 0 736318 4693294 235 18 IR SENSORS 249 71 71 249 253 CALIBRATION 0 0 AIRSPEED 13 12 5 12 5 10 GPS SOL 0 0 Oe O O NAVIGATTON Er e EK e Ou POE Oe 0 GPS 40 0 0 H rt 3 NAVIGATION 0 2r 0s Ue Us 6641 00 NAVIGATION 0 2 Oe Os O Ek EE 0 GPO O 10 02 E Oh ER 0s E A L BAT 0 64 0 0 1 364 0 U Figure 96 Data Acquisition during Manual Autopilot control This portion of data shows RC messaaes with complete RC commands from the remote controller and updated GPS positions Figure 96 shows data collected from two separate autopilot boards The autopilot boards are distinguished based on their autopilot identification number defined within the ground control station In this case the Jay autopilot configured board is identified as 2 and the Robin autopilot configuration is identified as 3 The airplane identification number is the second field within the telemetry data dir
71. Project Number WND1 Design of an Autonomous Platform for Search and Rescue UAV Networks A Major Qualifying Project Report submitted to the faculty of WORCESTER POLYTECHNIC INSTITUTE in partial fulfillment of the requirements for the degree of Bachelor of Science Submitted by Catherine Coleman Robotics Engineering and Mechanical Engineering Joseph Funk Electrical and Computer Engineering James Salvati Robotics Engineering and Electrical and Computer Engineering Christopher Whipple Robotics Engineering Advisors Professor Taskin Padir Robotics Engineering and Electrical and Computer Engineering Professor Alexander Wyglinski Electrical and Computer Engineering April 26 2012 Abstract In this report we present a platform for use in a system of unmanned aerial vehicles UAVs capable of human assisted autonomous and fully autonomous flight for search and rescue applications to improve the speed efficiency and safety of search and rescue to benefit both the victims and the rescuers alike This system also alleviates the need for large teams of rescuers to divide up and search vast areas of land were a stranded victim could be To accomplish this the system was designed to incorporate light long endurance UAVs equipped with specialized search and rescue sensors to aid humans in the search for lost hikers in mountainous areas The ability to search from the air without putting additional humans at risk is invaluable
72. Rectifier Negative Rectifier Figure 68 MeekPe PPM Encoder board block diagram The encoder board takes in all of the servo commands and then sums them together into a PPM signal which is easy to parse using the paparazzi radio configuration file Figure 69 is an image of the complete radio receiver system Once assembled the radio receiver system was attached to the electronics mounting board On the left side of the figure is the radio receiver and the right side is the MeekPe encoder board 59 Radio Receiver MeekPe Encoder Board Figure 69 Radio Control System for controlling the plane through the autopilot system Radio Control Configuration File The autopilot system uses the radio configuration file to parse the incoming PPM signal Figure 70 is an example of a radio configuration file See Appendix G User Manual Radio Controller Interface for more details lt DOCTYPE radio SYSTEM radio dtd gt lt radio name AR62Z00 data min 900 data max 3100 sync man 5000 syne max 15000 pulse type POSITIVE gt lt channel ctl AIL function ROLL min 1220 neutral 1620 max 2020 average 0 gt lt channel ctl AUX function FLAP min 1220 neutral 1620 max 2020 lt channel ctl ELE function PITCH min 1220 neutral 1640 max 2040 lt channel ctl GEAR function MODE min 1100 neutral 1760 max 2060 lt channel ctl RUD function YAW min 2260 neutral 2660 max 3080 lt channel ctil
73. S was configured properly the ground station laptop the autopilot controller and the GPS were brought outside so that the GPS could get a signal from GPS satellites After connecting to the autopilot controller from the ground station and then opening up the messages window updated GPS coordinates from the autopilot controller were viewed in the window These coordinates were in a universal transverse mercator UTM format and could be converted to latitude and longitude Mediatek GPS Within Robin io Figure 60 The mediatek GPS located at the front sm of Robin Figure 61 Mediatek GPS located at the front of Jay IR Thermopiles Next the IR Thermopiles within the airframe file had to be configured By loading the infrared_adc xml file as a module it arranged the ADC ports to sample the horizontal and vertical IR thermopiles Loading the infrared_adc xml file sets a make flag expecting the airframe configuration file to contain a section INFRARED shown in figure 62 53 lt section neme INFRARED prefix IR gt lt Configurations for the infrared thermopiles gt lt ADC neutrals gt lt define name ADC_IR1 NEUTRAL value 512 gt lt define name ADC IR2 NEUTRAL value 517 gt lt define name ADC TOP NEUTRAL value 514 gt lt define name LATERAL CORRECTION value 1 gt lt define name LONGITUDINAL CORRECTION value 1 gt lt define name VERTICAL CORRECTION value 1 gt
74. The location of where the flights will take place must be determined before moving to step 2 Considerations for the selection of a location should include A The scale of the flights If the scale is to be on the order of thousands of feet an AMA field will suffice B If the scale of the tests being conducted is in the scale of miles a large enough area of uninhabited land or airport will be required in order conduct the tests For example if the test being conducted is using a single eight foot wingspan RC drone the test field should be a standard AMA flying field If the test consists of multiple communicating UAV s with 8 foot wingspans the test area will need to be approximately 3 square miles of uninhabited space 2 Explanation of flight plans As far as the actual flight plans go it is important for any and all of the flight controllers to understand exactly what the robots are going to be doing not only on paper but also spatially in the real world Things to keep in mind include A Avoid flying over spectators and flight controllers Set up the flight plans to travel away from the safe zone B Ensure line of sight between were the robot is expected to go and where the flight controllers will be standing C Avoid trees D Avoid power lines by 5000 feet at all times If power lines are even present at the field reconsider the location How high and how fast the robots can fly are to be dictated by the FAA and AMA
75. UAV l SAR Platform Hardware Platform Team UNH Radio Hardware Team Communications Platform Team E mmm nm Se ee Hardware Comms Interface Figure 4 The project organization flow chart This illustrates how the different teams of Project WiND are organized and how they interact with each other This paper represents the work done by the Hardware Platform team in the lower left corner The software team at WPI was responsible for designing an algorithm to accurately and efficiently control the real world locations of the UAVs with respect to each other and the terrain being searched The algorithm uses a Google maps image of the area being searched and applies a matrix of hexagons and overlays the image with the hexagons These hexagon cells are then given values using a probabilistic map which is based off terrain data as well as information about the victim including their last known location Each cell is determined by basic assumptions of what the victim would Statistically do For example it is statistically unlikely that the person would climb to higher altitudes once they become lost The algorithm takes this statistic into account and gives a higher priority to the terrain at or below their last known position The software team was also actively involved with writing algorithms to perform image processing for the on board cameras A field programmable gate array FPGA was used to run the image processing algorithm
76. access to updating the waypoints from their system 87 UNITmeters xX 138 564 Y 240 S 100 TARGET TYPE WAYPOINT UNITmeters REFRESH x 0 Y 160 CONNECT Z 100 TYPE WAYPOINT UNITmeters xX 138 564 x ts Zz 100 TYPE WAYPOINT UNITmeters xX 138 564 y 80 Z 010 TYPE WAYPOINT UNITmeters x O Yy 160 zZ 10N grid rad cell rad units type so EN Bimeters f hexagonal INTEX Ina Ey init z torget alt 2 d K EH EE Z 100 submit GE Figure 100 Software integration team s GUI used to view the path of the UAV during a search and rescue mission Figure 100 shows an image taken from the software integration s control user interface for their search and rescue waypoint navigation routine The waypoints inserted into the simulation was generated from the output of their path planning software 6 2 Camera During the final flight of the Telemaster the camera gimbal was setup with a Logitech web camera which was controlled by the software team s image acquisition system After approximately a minute and a half of image collection the software stopped collecting images which was before takeoff The cause of the pause in image collection was caused by USB problems inherent to the use of the linux distribution on their board More details on the camera is discussed in the camera gimbal section of the platform development chapter of the report 88 7 Results We created a list of goals for this project at the very
77. ach maintains regulation over a wide range of input voltages with optimal conversion efficiency in the buck mode and a glitch free output during mode transitions This easy to use controller includes drivers for the high side buck MOSFET and the low side boost MOSFET The regulators control method is based upon current mode control utilizing an em Package ulated current ramp Emulated current mode control reduces TSSOP 20EP Exposed pad noise sensitivity of the pulse width modulation circuit allow ing reliable control of the very small duty cycles necessary in high input voltage applications Additional protection features include current limit thermal shutdown and an enable input The device is available in a power enhanced TSSOP 20 package featuring an exposed die attach pad to aid thermal dissipation Ultra wide input voltage range from 3V to 75V Emulated peak current mode control Smooth transition between step down and step up modes Switching frequency programmable to 500KHz Oscillator synchronization capability Internal high voltage bias regulator Integrated high and low side gate drivers Programmable soft start time Ultra low shutdown current Enable input wide bandwidth error amplifier 1 5 feedback reference accuracy Thermal shutdown 49 01 U0D JSOOg yONg sbuey ofguoun PIM ELLSNT Typical Application Circuit LM5118 VOUT IH a 30058501 2008 National Semiconductor Corporation 300585 www nationa
78. also a very easy material to work with since it can be 12 easily shaped by either a hot knife or hot wire These planes are often creating using sheets of Polystyrene Blue Polyurethane PVC Foam or Honeycomb foam Polystyrene is most people s first choice and is commonly used in the wings However gas and other solvents dissolve it Polyurethane is commonly used in fuselage construction because it is resistant to solvents PVC foam is also resistant to most solvents in addition to being able to withstand high temperatures The advantage of this building technique is that it ends up with very smooth surfaces at a low cost Metal Another material used when building homemade aircrafts is metal These planes are more challenging to build and require metal cutting and shaping tools There are three main types of metal construction sheet aluminum tube aluminum or welded steel tubes Planes created out of tubes are similar to wooden aircrafts and are usually covered in aircraft fabric However since they are made from metal they don t require as complicated a support structure in addition to being harder to damage Sheet metal aircrafts are popular because they are easy to construct and fairly light for their durability Composite Materials Another common practice is to make a composite material frame from a mold or by rapping a foam part Alexander 1997 Composite is usually only used on larger airplanes because of how heavy the final pro
79. amplifier zero cancels the modulator pole leaving a single pose response at the crossover frequency of the loop gain if the crossover frequen cy is much lower than the right half plane zero frequency A single pole response at the crossover frequency yields a very stable loop with 90 degrees of phase margin For the design example a target loop bandwidth crossover frequency of 2 0 kHz was selected about 30 of the right half plane zero frequency The error amplifier zero fz should be selected at a frequency near that of the modulator pole and much less than the target crossover frequency This constrains the product of R4 and C18 for a desired compen sation network zero to be less than 2 kHz Increasing R4 while proportionally decreasing C18 increases the error amp gain Conversely decreasing R4 while proportionally increas ing C18 decreases the error amp gain For the design exam ple C18 was selected for 4 7 nF and R4 was selected to be 10 kQ These values set the compensation network zero at 149 Hz The overall loop gain can be predicted as the sum in dB of the modulator gain and the error amp gain If a network analyzer is available the modulator gain can be measured and the error amplifier gain can be configured for the desired loop transfer function If a network analyzer is not available the error amplifier compensation components can be designed with the guidelines given Step load transient tests can be performed to
80. and it was available at the time The size and weight difference of the YAPA 2 compared to the other boards is insignificant compared to the design specifications of the UAV Table 8 Decision between which paparazzi autopilot board to use Sapatazz Lisa M YAPA 2 TWOG Controllers STM32F103RE ARM 7 LPC2148 ARM 7 LPC2148 a E T T RER CSR sP 2 weg JI mm JI E 33mm x 56mm 80mm x 40mm 40 2mm x 30 5mm Betiphevals Xbeeheaders OOOO O 3 2 3 Autopilot Configuration Flying a paparazzi autopilot system on an airframe requires all of the components of the autopilot system to be configured correctly The autopilot software consists of five xml configuration files which are compiled together and then loaded on to the autopilot controller Figure 57 is a summary chart of the configuration files 50 Airframe Handles Flight Sensors Control Surfaces And Flight Parameters Telem etry Radio Specifies the messages and the rate they are lansmitied Defines the structure of the Radio Receiver Flight Plan Settings Contains default Allows variables waypoints and from airframe to navigation be modified from routines GCS live Figure 57 The paparazzi configuration files allow for the complete configuration of the paparazzi autopilot system This allows for many different types of airframe structures and sensor combinations to be implemented 3 2 3 1 Airframe Configuration File The airframe configuration file consists of the
81. anguage OCAML is currently not 85 supported by the linux distribution used by the software team on the mother ship A new program will have to be designed to have the software team s boards connect to autopilot boards and then send commands to update waypoints p pyproj Proj proj utm zone 18 ellps WGS84 lat lon 42 355648 72 131113 homeX homeY p lon lat lon lat p homeX x homeYty inverse True server ivy IvyServer Python Server server start time sleep 0 1 Server send Meg round MOVE WAY POUNT 3 or Stir vate att oe Ste kom ae On Figure 98 Portion of the waypoint insertion script This portion of code written in python inserted a target waypoint in x y meters relative to home into a paparazzi instance As a proof of concept the software team generated a list of waypoints from their spiral navigation routine shown in Figure 99 and was inserted one by one into the paparazzi simulation using the python script mentioned in Figure 98 86 wv os www ocs wv as Ram Maps Help TelemasterTest 93 42355995 72 125773 1 0 WM 42355995 72 125773 1 0 i k Nav Maps Help TelemasterTet b Nav Maps Help TelemasterTest 8 w wass 242355995 29128 i i 22 27 22 TelemasterTest Geo in 4 Na 2227 22 TelemasterTest AUTO cl E i Pri Settings A 22 27 22 TelemasterTest mayda cuss ZAQ Fiche Pian GPS PFO Mise settings A RC soni EEN TelemastecTes
82. anned Meteorological Observer SUMO A new tool for atmospheric boundary layer research Meteorologische Zeitschrift vol 18 nu 2 pp 141 147 Available http www ingentaconnect com ezproxy wpi edu content schweiz mz 2009 00000018 0 0000002 art00004 Zhihai He Iyer R V Chandler P R 2006 June Vision based UAV flight control and obstacle avoidance American Control Conference 2006 online vol no pp 5 pp 14 16 doi 10 1109 ACC 2006 1656540 Available http ieeexplore ieee org stamp stamp jsp tp amp arnumber 1656540 amp isnumber 34689 98 Appendix Contents APPENDIX A SAFETY MANUAL OF PROJECT WIRE iere 100 APPENDIX B PROJECT WIND INCIDENT REPORT ccscsscsesssssssescssevessssssscsceseveuseseseeeceseveusesesesesesevaususeaesesevevavsuseseeneevevananss 108 APPENDIX C PROJECT WIND LIABILITY RELEASE FORM v cccccscscssescssssscscssevessssssscsceseveuseseseceseveveususeseseseveveuseseseensevevenseas 109 APPENDIX D MASTER BUDGET LIST NN 113 APPENDIX E DETALED FLIGHT DE 114 APPENDIX HEISER EA 116 APPENDIX G POWER BOARD SCHEMATIC usscssssssesessessssesesseuessesessesessoueusesessenesseuauseueussaevouauseuessasaeseuausesassauaevevauseueusasauvevauanas 132 Ve 20509 Bs IF 14 Po Od Bt DATASHEET eean ee ee 141 99 Appendix A Safety Manual of Project Wind The Safety Manual for Project WiND In Case of Emergency Call 911 Safety Protocol Project WiND is dedicated to safety This manual has been developed to ensu
83. aparazzi enac fr wiki Y APA v2 0 From the vendor the paparazzi board does not come with an usb bootloader installed on the device The bootloader provides the computer a ttyUSBO serial port for downloading to the device Without the bootloader the device will only be able to be programed through the USART1 port labeled as the GPS pins If you plug the autopilot into the computer and then supply power to the pins labeled bat 6v 18v and then open up a terminal window and path to Cd dev There should be a ttyUSBO available If it is not there and the light on the board is not blinking you will need to install the usb bootloader If there is a tty USBO you may skip the boot loader installation guide USB Bootloader Instructions 1 Obtain a FTDI 3 3 usb cable http www sparkfun com products 9717 This cable is recommended because the FTDI cables have known working drivers for linux operating systems 2 Plug the FTDI cable like below INSERT PICTURES 3 Plug in FTDI cable in to usb port on computer 4 In order to have the processor receive the bootloader code the boot pin on the processor needs to be connected to ground Near the xbee headers there is an area labeled boot Soldering a wire bridging the two vias will work After bootloader installation make sure you remove the wire 5 Power on device This must be done using a current limited power supply with a voltage between 7 10v 6 Open up a linux terminal a
84. aparazzi provides a 3d visualization of the simulated plane flying Figure 90 demonstrates a paparazzi simulation flying the plane within flight gear Fii jii ES I eevee F tj LU HEF TEE PERF H HTE ititi m cinieix enn Ae O e d F d o Ge X Kl WEE x Saw bai A A f t Ka s bet irar LNNT Si Ss Rate P ege kee H at Ki Mee neha m 8 D A gt a a o 2 on ci mios LR kt gegen Cid nortoe ES Time 0 24 pia uera rr Time 0 24 ZO rer ee A mt Sep L I WI chen eg H mm HiHIR mer OO Ur rtm SE een een e Time 0 45 Time 0 52 Hiki mer GSM mane PS PER mmm Sapa A b t i f H ru D NOD em Ars HG FEFEFE OT Figure 90 Flight Gear Simulation This multi image figure depicts the takeoff simulation of paparazzi alongside flight gear Flight gear is an open source radio control flight simulator The time of each picture was taken from the video is labeled 74 3 2 4 4 Multi Plane Simulation In addition to running single plane simulations paparazzi has the ability to simulate and connect to more than one plane Multiple planes can be simulated in the same fashion as a single plane See Appendix G User Manual Multi Plane connection for more details Once both of the airframes have been compiled the user executes the simulation for one and then selects
85. ary We had multiple flights during each of these tests We modified the airframe after each flight test to improve its flight characteristics The Telemaster plane was damaged during the second third fifth and seventh test and needed to be repaired On the final fight we lost control of its elevator and it flew into the trees and has been damaged beyond repair Due to our modifications we were able to salvage all of our electronics However the Blue Skyline Champ successfully flew under RC control The yellow Skyline Champ was never tested 5 PLATFORM RESULTS Based on information from the GPS we were able to confirm that we meet both our speed and altitude goals Altitude Plot 2 02 2012 15 18 43 Altitude Meters N N N N N LA LA O N CH Lei CO CH N ro Ei E CO KA CO CH Altitude 100 150 200 250 300 350 400 450 Time s Figure 3 Altitude Plot from February 2nd Flight Ei be CH CH LD CH 5 Velocity Plot 2 02 2012 15 18 03 30 LA N N u CH LI Velocity Meters second m CH Velocity je 50 100 150 200 250 300 350 400 450 Time s Figure 4 Velocity Plot from February 2nd Flight By comparing footage from a camera hard mounted to the plane and the one mounted in gimbal shows that we were able to eliminate the sine waves in the video LN Figure 5 Video recorded with the Vibration Figure 6 Video recorded without Vibration Dampening 6 CONTROL SYSYTEM The control
86. as to make new piece for the wing struts to connect to the wings To prevent the wings from shifting again we redesigned the way the wing attached to the plane February 9 flight For this flight we had our new method for attaching the wing finished This attachment was modeled after the method how the skyline champ attaches its wings and still included the rubber bands We also mounted the IR thermopiles and were able to calibrate them on the plane and test their functionality For this flight there was a light crosswind making it difficult to take off The goal of this trip was to test our previous modifications and to get the airframe to fly more stable and 114 predictable On the final take off Mr Gammon had trouble getting it off the ground and it resulted in an aborted sidewise landing breaking the wheel hub Our major accomplishment during this flight was flying RC mode through the decoder board and autopilot February 15 flight In addition to flying the telemaster we were also about to break in the other two engines for the Skyline Champs We added the new wheels on the telemaster Unfortunately the new wheels were not as good as the original and prevented us from taxing straight making lift offs challenging We also discovered that one of the wings had become twisted when we re heat shrunk the covering which made our plane turn to the right when cruising We also tested Auto 1 mode during flight During auto 1 the airplane turned to th
87. ased tracking and motion estimation for moving targets using small UAVs American Control Conference 2006 online vol no pp 6 pp 14 16 doi 10 1109 ACC 2006 1656418 Available http ieeexplore ieee org stamp stamp jsp tp amp arnumber 1656418 amp isnumber 34689 Euston M Coote P Mahony R Jonghyuk Kim Hamel T 2008 September A complementary filter for attitude estimation of a fixed wing UAV Intelligent Robots and Systems 2008 IROS 2008 IEEE RSJ International Conference online vol no pp 340 345 22 26 Sept 2008 doi 10 1109 IROS 2008 4650766 Available http ieeexplore ieee org stamp stamp jsp tp amp arnumber 4650766 amp isnumber 4650570 Garcia Esteban Gonzalez Becker John 2007 UAV stability derivatives estimation for hardware in the loop simulation of Piccolo autopilot by qualitative flight testing 1st Latin American UAV Conference online Available http www aerodreams uav com docs aeroduav conf pdf Jensen A M Baumann M YangQuan Chen 2008 July Low Cost Multispectral Aerial Imaging using Autonomous Runway Free Small Flying Wing Vehicles Geoscience and Remote Sensing Symposium 2008 IGARSS 2008 IEEE International online vol 5 no pp V 506 V 509 7 11 doi 10 1109 IGARSS 2008 4780140 Available http ieeexplore ieee org stamp stamp jsp tp S amp arnumber 4780140 amp isnumber 4780001 Joseph Lum Yue Hao 2011 Unmanned Aerial Vehicle Autopilot System onl
88. asterTest euer DE 9 16 46 08 J GPS pat Status AGL Bil Flight Plan GPS PFD Misc Settings 2 RC Setting 16 46 08 T GPS_SOL Time 08 46 VUE cl 16 46 08 J IR SENSORS Stage 00 00 v flight_ plan name Basic lon0 72 131113 16 46 08 J hee ETA N A 16 46 08 T NAVIGATION mea 16 46 08 T Mark Ser oai NAVIGATION_REF am Target Alt exceptions 16 46 09 T PONG 245m Om 245m e 16 46 09 T PPM 16 46 09 T PPRZ MODE weit CES Nav nico CE eent PPRZM Bat Status AGL Block z Q gt block Geo init 16 46 10 T RC Time 0759 ma ma gt block Holding point biep STATE_FILTER_STATUS era nja E lock Takeoff 16 46 10T WP_MOVED Mark le bid gt weg amer 16 46 11 Tece roy EA H Set mme 95 Multi plane connection This image demonstrates connectivity between two separate autopilot boards Figure 95 demonstrates the connection between two separate autopilot boards The telemetry from both autopilot boards are recorded within one data file where the planes can be identified by its aircraft id number 81 de de d 133 EE Lis i Lis E 14 RE 044 ice 14 d 14 LA 14 52 9 Set sad 2259 pay 2249 BAO Poy 12930 2340 14 ta 14 ioe d tA 14 tA 14 14 14 14 14 14 14 14 14 14 14 14 877 gzl AS Jal 941 FOZ 964 004 00 5 BEES 049 e L33 L6 154 168 418 424 440 450 453 455 465 467 MM WN WN WWWWNNDN GO GO GO b i GO GO b i WN WN WN WN WNDN WN W W PD AERO
89. ated to a waypoint with a target altitude of 75m shown as the horizontal line at 75 meters Without kd increasing kp from 20000 to 5000 resulted in a more damped altitude response For the next set of simulations kd was reduced to 500 and produced an expected response Takeoff Pitch_Kd 500 Altitude Meters Pitch_Kp 20000 Pitch_Kp 10000 Target Altitude 0 20 40 60 80 100 120 140 160 Time s Figure 83 Pitch Launch Simulation Kd 500 The graph above shows three simulations where the kd constant was kept at 500 and then the kp constant was varied 69 In Figure 83 decreasing kd resulted in a more oscillatory launch The proportional constant started at 20000 then reduced to 10000 as before but the third simulation with kp of 5000 failed to launch For the final pitch simulation the derivative constant was increased to 500 The resulting graph is illustrated in Figure 84 Takeoff Pitch Kd 500 Altitude Meters Pitch_Kp 20000 Pitch Kp 10000 Pitch _Kp 5000 Target Altitude 0 20 40 60 80 100 120 140 160 180 Time s Figure 84 Pitch Launch Simulation Kd 500 The graph above shows three simulations where the kd constant was kept at 500 and then the kp constant was varied Increasing kd resulted in the slowest launch but possessed the least amount of oscillations As kp was increased from 20000 to 5000 the simulated planes assent increased and resulted in an overshoot at kp 5000 As a resul
90. ation made was installing the gas tank Initially a gas tank was installed as far forward and up against the front firewall of the airframe A floor in the tank compartment was installed and walled it off from the rest of the plane interior compartment It was made fuel proof by painting the compartment with oil based paint and sealed the cracks with hot glue as seen in Figure 23 22 Figure 23 Gas tank in its original position all the way forward The rest of the modifications where made based on the results gathered in our flights The flights are discussed in detail the testing section 2 2 9 Camera Gimbal A camera gimbal capable of containing two different cameras the Sony block camera color and the Flir Tau 640 thermal infrared was designed The gimbal serves two different purposes to maximize the cameras view and reduce vibrations from the engine and propeller to the camera Each camera had to look down through their own dome instead of sharing one which meant they each had to be on their own gimbal set up Figure 24 Sony color block camera that we will put in the planes Motion from the servos is transferred to the gimbal by linkages Linkages were chosen over gears pulleys and strings because of the vibrations in the system caused by the engine The vibrations would cause the gears to quickly get worn out and increase uncertainty in its position Gears would also transfer and magnify all of the vibrations going through them
91. autonomous and fully autonomous flight for search and rescue applications to improve the speed efficiency and safety of search and rescue to benefit both the victims and the rescuers alike To accomplish this the platform was designed to be lightweight with long endurance equipped with specialized search and rescue sensors and utilizes the paparazzi autopilot system which is an open source Linux based autopilot package for flight stability and autonomous control This project worked in conjunction with two other WPI MQPs an AI Image processing team and a communications team as well as two teams from the University of New Hampshire which built the communications hardware and UI to realize the full system including inter UAV communications high level search algorithms and ground control station with a user interface 1 INTRODUCTION Hiking is a very popular activity for people across the globe Some hikers are leisure seekers looking to get away from the sights and sounds of a city and escape to the great outdoors Others are serious hikers who are exhilarated by the danger and challenges presented by attempting to climb a 4000 foot tall mountain Unfortunately each year thousands of people in the US get lost or injured while hiking and must be rescued by professional search and rescue teams In fact just in America s National parks from 1992 to 2007 there were 78 488 individuals involved in 65 439 search and rescue incident
92. be entered into the radio configuration file 14 Now measure the rest of the channels Notating all of the values 15 Before disconnecting we need to take the following measurements 1 Synchronization Packet 2 Max packet Size t1 t2 t3 t4 t5 t6 i Synchro Blank Time note 2 Peer E ein RE pal Petes pap H E e Received PPM Frame e d Channel 1 Servo Signal i i Channel 2 Servo Signal i Synchro Detector Output tt ee note 3 Figure 105 PPM Structure 16 Now open the configuration file associated with your radio system If one does not exist copy an existing one and make the same following changes 17 Add in the Channel readings to your radio configuration file For example if the first channel is AIL and the readings were 1220 1620 and 2020 for min neutral and max it will be set as the following lt channel ctl AIL function ROLL min 1220 neutral 1620 max 2020 average 0 gt 18 Below is an example of a completed radio configuration file lt DOCTYPE radio SYSTEM radio dtd gt lt radio name AR6200 data_min 900 data_max 3100 sync_min 5000 sync_max 15000 pulse_type POSITIVE gt lt channel ctl AIL function ROLL min 1220 neutral 1620 max 2020 average 0 gt lt channel ctl AUX function FLAP min 1220 neutral 1620 max 2020 average 0 gt lt channel ctl ELE function PITCH min 1220 neutral 1640 max 2
93. ble of supplying 102 watts of power to on board electronics for a minimum hour per charge e Contains a pan tilts camera gimbal capable of holding up to two cameras one color camera and one infrared camera These specifications are necessary metrics for the success of the project For example it is important for the flight time to be in excess of 1 hour Otherwise the UAVs will be unable to cover any significant area per fueling which would make the system a hindrance as opposed to an asset to the search teams Similarly the power and maximum payload requirements are also important and have been derived from the needs of the other teams of project WiND With a system that meets these specifications the network will be capable of flying up to 30 miles on a single flight The efficiency of the search algorithm varies depending on the terrain being searched as well as other factors however this could translate to a round trip search of 38 250 000ft at 400 feet in altitude per aircraft 3 PLATFORM EXECUTION After gaining an understanding of the problem we entered the execution phase of the project During this phase we designed built and tested our UAVs 3 3 PARTS SELECTION AND MODIFICATION We choose to use the Senior Telemaster and two Skyline Champ airframes during this process They were chosen for their stable flight characteristics and large payload capacity We choose to use a 20 cc gasoline engine for the Telemaster and a
94. blems easier For the first flight the electronic ignition system was installed and secured in the forward compartment under the gas tank and the ignition battery was mounted behind the gas tank with the cables running under the tank to the ignition coil After the gas tank was moved the cable was not long enough to reach the ignition coil This required an access hatch to be installed to the lower compartment The hatch allowed easy access to this compartment which is where the ignition battery and the ignition coil are now stored for flight A cross section view of the this compartment and the floor which the gas tank rests on can be seen in Figure 41 35 Gas tank chamber floor Entrance to the electronic ignition chamber Figure 41 in side of Robin showing the different compartments The most significant modification to the airframe was the wings attachment method This change was deemed necessary after the airframe sustained damage during one of its earlier flights On that flight the wings shifted breaking one of the attachment points on the wing struts The wing attachment was always a concern especially since the team needed to load up the plane with a lot more weight than the plane was intended for To fix this problem the team made the wings attach ina similar way to the Skyline Champ Pegs were installed on the leading edge of the wings and drilled holes in the rear of the wing to allow a 14 20 screw to secure it to a piece of ha
95. both simultaneously See Appendix G User Manual Multiplane Connection for more information The aircraft identification number distinguishes the UAVs from one another on the ground control station end The aircraft id number is defined in the configuration file for the list of optional aircrafts within the paparazzi main window GPS With the ground station successfully communicating to the autopilot controller the GPS was interfaced with the autopilot controller next To connect the GPS a 4 wire 100mil header that was soldered directly to the GPS adapter and then connected to the 5 pin header located on the board labeled GPS Next the airframe configuration file had to be updated to communicate with the GPS lt subsystem name gps type mediatek_diy gt Figure 59 Adding in GPS subsystem This line of code from within the airframe configuration file will add the mediatek_diy GPS module to the airframe By defining the GPS subsystem when the airframe is compiled it sees that the GPS subsystem is defined and it uses the settings defined by the type The type in this case is the mediatek_diy which 52 corresponds to the GPS that was selected The configuration file for a mediatek GPS was conveniently within the Paparazzi source code which saved time required to write a new firmware file to interface with the GPS Once the GPS was configured the airframe file was compiled and downloaded to the autopilot controller To confirm that the GP
96. buy transport and replace Through the use of UAVs in search and rescue it is possible to decrease the amount of resources needed in the initial search and still increase the chance for success This is where our project plans to improve search and rescue using an autonomous UAV network to create and execute a methodical search pattern from the air thereby limiting the number of rescuers put in harm s way 1 3 How UAVS are being used UAVs are multi purpose vehicles that have been constantly evolving since their creation They have a wide variety of roles from scientific exploration to armed military attacks There is only one significant difference between a UAV and traditional aerial vehicles which is the human interface Traditional aerial vehicles need to carry a human on board to function as a pilot This then requires a great deal of support for the pilot and crew aboard a vehicle including space for the people to sit as well as life support systems All of this adds weight to the aircraft requiring a large aircraft to lift the extra weight If you remove the human from the aircraft there is room for more capabilities Without the human on board flight times can be unlimited the airframe can be smaller and more sensors computers weapons or whatever the role of the aircraft requires can be added One of the most critical roles for UAVs is remote sensing and surveillance UAVs were originally used as reconnaissance drones in high ri
97. cal private airport the team tested ENEE Eeer Eelere 62 Figure 73 Wait GPS block within flight plan This is an example of programmable blocks or steps within the flight plan This example will run at the beginning of AUTO2 and until the GPS fix is valid SEENEN eebe 62 Figure 74 Line navigation routine callback button This block within the flight plan configuration file creates a function callback to the line navigation routine ccc cece eecceeeseeceeeeeeceeeseeeeeeaeeseeseeees 62 Figure 75 Settings Tab within Ground Station cccccccccccseccceeececeeeeeaeeeeseecessaeeeseeeesseeeeseeeeseaees 63 Figure 76 GPS Message Structure The GPS messages from simulations contain the position of the aircraft which was used to examine the effect of changing the parameters of the control loops Figure 77 Paparazzi Autopilot Control Loop Structure The overall structure features two main control loops one for vertical and one for horizontal where the final output of each control loop define target positions for the control surfaces driven by the ServoS cccceecceceeeeseeeeeeeeeeaeeees 65 Figure 78 Vertical Control Loop 66 left PCM COMO LOOD E 66 Figure 80 Elevator Position Control Loop 67 Figure 81 Screen capture of the ground control station during a launch simulation a00neaanna 68 Figure 82 Pitch Launch Simulation where Kd 0 This graph shows three different simulations where the kd constan
98. cccccseccceeeeseeeseeeeceeeeeeeeseeeeseeeseeeeseees 26 Figure 31 The quick connect values from inside the body of the plane with reinforcing plate 27 Figure 32 The rubber grommets attaching the engine to the fuselage ccceseceeeeeeeeeeeeeeeeeees 27 Figure 33 Yellow Skyline Champ Duck partially assembled ce ccceeeceeeeeceeeeeseeeeeeeeeseeessaees 28 Figure 34 LM5118 efficiency une 30 Figure 35 Standard configuration for Duck boost regulator ccceececseeeeceeeeeeeeeeeeeeeseeeeeseeeesaaees 30 Figure 36 Configuration used in our schemaic 31 Figure 3 7 Controller Circuit DiagraiTi xisccirsatavtisaceoscetasiecditanpeuciias a aa aa Rt 31 Figure 38 Images from the video of Robin s Take off out at Tanner Hiller ccceeeceeeeeeeeeeees 33 Figure 39 Images from the video of Jay s take off at Tanner Hier 33 Figure 40 Gas tank in its final position moved 4 inches back 35 Figure 41 in side of Robin showing the different compartmenmts 36 Figure 42 Aluminum support frame inside of Robin with the wooden mounting plate for the wings EE 36 Figure 43 What remains of the bottom of Robin s fuselage after its February 18th crash Notice how it is missing its landing gear and wing strut attachment points The Aluminum frame prevented iB alate ao f e aenmener ean tee ene nee ene rey mee ret ene eran ee nee ce me nee ne eee me ane eee eer nec ee 37 Figure 44 Robin after its repairs from the February 18th
99. d 1 05 gt lt message name BAT period 1 1 gt Above is an example of some of the messages that are sent from the default telemetry file After testing the autopilot in the air we will begin removing unnecessary messages Magar e RA ACTUATORS ind tootieicornrh E vun woe ive rtl ee iia ime ee Pe ed em unt Le Fight tine it D O Wits IR See thrathe fbn 4 D oiite bleck irr Il zu DESAED wint H skaga Hra a np TH Volt DEHLIN E DENK PAK STATAS BS ENERGY ES TiS FRY STATIS GPS Ca So Cy IR SEHMSCORS PONG PERZ MODE STATE _FRTER_ S TATUS WIP MOD ined energy mani 0 Figure Above is an example of the messages window provided by the ground station to view incoming messages from the UAV The bat message is currently selected and shows values such as voltage and current from the battery 93 355 8 NAVIGATION 21 2 44 0 21 900 93 375 86 GPS 3 26653456 468411392 2955 160370 37 28 1662 25237375019 1 93 423 8 WP_MOVED 15 268414 5 4684145 5 234 559998 19 93 424 6 CALIBRATION 0 0 93 519 6 AIRSPEED 15 14 5 14 5 6 93 603 6 NAVIGATION 2 1 2 4 4 0 21 900 93 631 8 GPS 3 26853456 468411392 2988 160290 34 32 1662 252374000 19 H 93 632 8 NAVIGATION 21 2 44 0 21 900 93 719 8 ATTITUDE 1 925012 5 238955 1 318443 93 823 amp ESTIMATOR 0 0 93 831 8 DESIRED 0 0 24 0 0 0 45 0 93 855 6 NAVIGATION 21 2 44 0 21 900 93 875 6 GPS 3 26653456 468411392 3001 160250 32 16 1662 252374250 19 1 93 919
100. d 27 depict the material properties of three different silicon with different Shore A hardness indexes Shore A is standard for measuring the hardness of different soft solids The optimal load for each of these materials was based on their thickness Frequency Response for S 1 Test load 0 5 kg s 4 AU 60 Frequency Hz Figure 25 Frequency responded for a silicon with a 6 on the Shore A hardness scale and optimal load of 0 2 0 75 kg 4 legs Frequency Response for A 1 Test load 1 5 kg s 4 40 60 Frequency Hz Figure 26 Frequency responded for a silicon with a 10 on the Shore A hardness scale and optimal load of 0 5 2 5 kg 4 legs 24 Frequency Response for B 1 Test load 9 5 kg s 4 40 60 Frequency Hz Figure 27 Frequency responded for a silicon with a 14 on the Shore A hardness scale and optimal load of 4 15 kg 4 legs Different materials protect against sheer and compressive vibrations differently Based on this information a material with a Shore A hardness index of 12 whose optimal load was about 5 kg per connection point was required This loading was based on the CAD model and the weight of the components it needed to support This led the team to purchase a 1 8 inch thick silicon based foam from McMaster Carr Dampening Pad Figure 28 CAD of Camera Gimbal with Sony camera 25 However because of a lack of funding we were unable to acquire a Flir camera However the option
101. d a current rating of IOUT A conservative design would at least double the advertised diode rating since spec ifications between manufacturers vary For the reference de sign a 100V 10A Schottky ina D2PAK package was selected C1 C5 INPUT CAPACITORS A typical regulator supply voltage has a large source impedance at the switching frequency Good quality input ca pacitors are necessary to limit the ripple voltage at the VIN pin while supplying most of the switch current during the buck switch on time When the buck switch turns on the current into the buck switch steps from zero to the lower peak of the inductor current waveform then ramps up to the peak value and then drops to the zero at turn off The RMS current rating of the input capacitors depends on which mode of operation is most critical IRms euck lout D 1 D This value is a maximum at 50 duty cycle which corre sponds to VIN 75 volts IRMS BUCK BOOST ay D 1 D 1 D Checking both modes of operation we find IRms Buck 1 5 Amps lRMs BUCK BOosT 4 7 Amps Therefore C1 C5 should be sized to handle 4 7A of ripple current Quality ceramic capacitors with a low ESR should be selected To allow for capacitor tolerances four 2 2 uF 100V ceramic capacitors will be used If step input voltage tran sients are expected near the maximum rating of the LM5118 a careful evaluation of the ringing and possible spikes at the device VIN pin should be co
102. d shelf him The plane will have to be completed by future teams before Duck can join Jay and Robin in the air The progress on Duck is summarized in the list below e Engine broken in e Propeller modified for engine e Landing gear attached e Tail attached e All control surfaces attached e Servos for the ailerons elevator and rudder mounted e Control linkages for the ailerons and rudder are completed e Rear landing wheel is mounted Figure 33 Yellow Skyline Champ Duck partially assembled For Duck to be completed more items need to be purchased For RC flight Duck needs new wheels a gas tank an engine dampening plate flexible linkage for the throttle a receiver and two quick disconnect valves For autonomous flight it would need a YAPA2 autopilot and GPS All of the other sensors and supplies have already been purchased For Duck to be equipped to satisfy the goals of Project WiND and have coordinated search flight with the other planes it will need the higher level boards an image processing board power board Wi Fi module and a camera mount designed and installed 2 2 7 Power Board Design As the plane came together and the other teams got their ideas together of what they will need for their projects the need for a power management system became more apparent This power system needs to be able to power all the systems on the plane as well as to be able to turn off unnecessary systems when power starts to get low The lis
103. d to the GEAR channel which was defined as MODE within the radio configuration file Debugging Radio Communications To determine if the autopilot board is properly receiving all radio channels from the radio receiver 1 Activate the PPM messages within the Telemetry messages see Telemetry Messages for definition The default telemetry message packet does not contain it To add it in go to your airframe configuration file and add the following line under the fixedwing section 128 lt define name TELEMETRY MODE FBW value 1 gt 2 After communicating to the board you should see PPM messages within the messages window See GCS configuration if not 3 This window shows the PPM packet parsed into the corresponding channels 4 There should be changing values in the 20000 range for each of the channels you defined If there are unchanging channels or there are no channels check your connection and your channel measurements 5 The GCS contains a RC status light if it is Green you know it 1s all set else wise it is red and unable to properly read RC messages Developers Guide Now that you have paparazzi up and running the goal of the developers section is to provide insight on where major components of the source code are Configuration Files As seen so far the major way modify the code you download to the autopilot is driven by the configuration file system All of the configuration files are stored in paparazzi conf
104. der Autopilot control Three Drones fly under Autopilot control WE Figure 97 The General Gantt chart as predicted by the team in the beginning of October 2011 4 1 Timeline with regards to the Hardware team The first major milestone in the testing section is the completion of the first airframe ready for radio control testing by the week of November 21 This milestone was completed on time and there were flights in November of 2011 of Robin The next testing milestone was scheduled for completion the week of December 5 2011 and that was an autopilot test of the first airframe Robin This milestone was not met on time the main reason for which was that there was no additional time given to properly tweak Robin to provide stable enough flight to give control over to the autopilot The task of getting the airframe to consistently and predictably fly straight and level proved to be more of a challenge than originally anticipated This required multiple trips to the test site with Mr Gammond the RC expert and pilot for the team Each trip would result in multiple flights and after each flight Mr Gammond would give a short briefing to the team regarding alterations that would improve flight performance ultimately leading to the desired flight characteristics needed to ease the work the autopilot would need to do to keep the plane on course For a complete list of flights and the results from each flight refer to section 2 3 This list also ill
105. der to ensure continued safety project WIND has created an Incident report form This form found as Appendix B of this document is to be filled out in its entirety and returned to the team captain the team advisors as well as WPI s safety coordinator in compliance with the WPI safety regulations If the incident was an avoidable accident then the safety manual shall be edited and revised to help prevent the incident from occurring again Remember Project WIND has specified these outlines with your safety in mind however it is your responsibility to abide by these rules and ensure safe robot operation for all l your name printed hereby agree and certify that have read and understood all the material covered in The Project WiND safety manual and agree to abide by all rules and regulations as specified by project WIND Signature Date 107 Appendix B Project WIND Incident Report This is the official project WiND Incident report Please fill out all of the fields and submit a copy of the completed form to Your team leader Name Project WiND Student Lead Name Faculty Advisor s Name Name WPI s Safety Coordinator Name Date Location of Incident Person s Involved Name Name Name Explanation of Events Your Name Printed Your Signature Date 108 Appendix C Project WIND Liability Release Form WORCESTER POLYTECHNIC INSTITUTE LIABILITY RELEASE FORM SPECIAL ACTIVITY Project WIND Test
106. duct is Composite airplanes consist of a core material a reinforcement material and a resin Core materials are most commonly made from foam however other materials like wood and honeycomb are also used The most common foam used in airplane construction Polystyrene can t be used with polyester vinyl resins This material provides the shape of the part and supports it during the curing process There are three main types of reinforcement materials fiberglass carbon fiber and Kevlar Harris 2005 Fiberglass is the most widely for reinforcing the size planes that will be used in this project It also comes in various weights While e glass fiberglass is the most common s glass fiberglass which is 30 stronger and 2 3x the cost is also used Carbon fiber is the strongest Some negative qualities of these materials include how difficult it is to use and how useless it is after breaking The last material used is Kevlar This material is the least popular since it is difficult to work with and has a low compression strength The advantage of using this material is that it is tensile strength All of these different reinforcement materials come in either unidirectional or bi direction weaves Alexander 1999 Bi directional weaves are usually more expensive because they can handle forces coming from more directions so they are less likely to break but not necessary in every application The last component to a composite airframe is the res
107. e The commands section defines the name of the servos which are connected to the control surfaces how they are mixed together and how they affect the roll pitch yaw and throttle of the UAV lt servos gt lt define the servo ports and their min neutral max values gt lt servo name MOTOR no 0 min 1000 neutral 1440 max 1960 gt lt servo name AILEVON LEFT no 1 min 1000 neutral 1500 max 2000 gt lt servo Name j RUDDER no 2 min LO40 neutral 14420 max 1840 7 gt lt servo name AILEVON RIGHT no 3 min 1000 neutral 1500 max 2000 gt lt Servo Name ELEVATOR noHj 4 man Les0 neutral 1440 max 040 7 gt lt servos gt Figure 63 Definition of the servos within the airframe configuration file These definitions set the neutrals minimum and maximum positions for the control surfaces of the UAV The servos section defines the name of each of the servos the channel number the servo is connected to and the min max and neutral values the servos can be set too The neutral value is the default value for the servo See Appendix G User manual Configuring Control Surfaces for more detail Flight Parameters Before flying autonomously the flight parameters had to be defined Flight parameters consist of two major sections titled VERTICAL CONTROL and HORIZONTAL CONTROL The vertical control section contains parameters to set the limit for the throttle and pitch as well as t
108. e applied A piece of 1 8 inch plywood was glued behind the outer sheet of the body of the airframe to reinforce the area where the valves were installed as seen in Figure 31 Figure 31 The quick connect values from inside the body of the plane with reinforcing plate From flying Robin the engine had to have some right and down thrust built in to the mounting of the engine for straight predictable flight Jay came with a wooden box intended for the electric motor that had these offsets built in These standard offsets were 3 degrees down and 3 degrees to the right Since an electric motor was not used these offsets needed to be recreated for the gas engine When mounting the engine washers were placed behind the mounting points to duplicate this offset The motor was installed on a vibration dampening plate to help protect the electronics from the engine vibrations This plate was mounted to the airframe using four 44 20 bolt through rubber grommets as seen in Figure 32 Figure 32 The rubber grommets attaching the engine to the fuselage 2 Finally for the throttle linkage a flexible cable was used after the frustrating attempts to use a solid linkage in Robin Unlike Robin the return spring was kept on the carburetor to allow better response in decreasing the throttle with the cable system 2 2 6 Duck Air Frame Modification Because of the setbacks from Robin the team made the executive decision to stop Ducks construction half way an
109. e right however the twisted wing could have caused that We also lost our downlink before the flight so no definitive data could be gathered to help tune it February 18 flight For this flight we straightened out the wheels and fixed the twist in the wing We also put our new decoder board in the plane We also have some crosswind during our take off After the first flight we discovered that it interpreted the signals differently from the original board and was having over flow issues on the rudder control Because of this we were not able to test Auto 1 again After changing it back to purely RC with out routing the signal through the decoder board we attempted to have a second flight However it was caught be a cross wind before we fully got up and off the ground The wind caused the plane to roll to the right to the point the wing caught the ground and caused it to hit the ground sideways ripping off the landing gear and the bottom floor of the airplane Fortunately the aluminum frame saved most of the plane making the damage minimal 115 Appendix G User Manual Paparazzi Autopilot User Manual This User manual is written to guide the user through configuration and operation of both the paparazzi Ground station software and modifying and downloading the configuration files necessary for the autopilot board 116 Autopilot The autopilot board we used for our MQP was a YAPA2 The documentation for the board can be found here http p
110. e they were in the air Figure 38 Images from the video of Robin s Take off out at Tanner Hiller WITT RE Figure 39 Images from the video of Jay s take off at Tanner Hiller Testing occurred on seven different occasions Each of these trips had a different goal with different lessons Table 3 summarizes the results from these flights and the resulting changes to the airframes 33 Table 3 Test day summary results based on outcomes Resulting Changes Nov 13 Robin During Aggressive climbs the Altered engine mount thrust angles RC Flight plane pulled to the right Changed rudder servo to faster one Engine had a non linear Moved the gas tank back 4 inches response to throttle control Moved the throttle servo forward Engine stalled in final flight Pressurized the gas tank with muffler Fix rudder and elevator horns Feb 2 Robin Successful GPS downlink Wing strut replaced with stronger RC Flight Nipple of muffler melted off alternatives Wings shifted and sheared off Reduced the throw of the control wing struts connection surfaces Added Aluminum Frame Added Hard Mount points on wings Mounted the IR sensors Feb 9 RC Flight Calibrated thermo sensors on Re shrunk the monokote Through plane Replaced the broken wheel decoder Sideways landing broke Board wheel Feb 15 30 cc engines broken in Fixed the torqued wing Found we couldn t taxi strait Fixed the orientation of the wh
111. e to be used interchangeably Academy for Model Aeronautics The Academy for Model Aeronautics abbreviated to AMA is a nationwide governing body for the safe use of radio controlled RC aircraft including both planes and helicopters AMA offers certification to prospective RC pilots Members have access to fly at AMA flying fields around the country Certification also offers the certified member some insurance to help with expenses in the case of property damage due to a crash See Appendix D for more details on the benefits of AMA and their rules and regulations Project WIND will follow all of the AMA safety regulations in addition to the regulations specified in this document Definition of Robot States During the test each robot will go through a series of states defined here Name Systems Active People allowed near robot Note Used for Maintenance and inspection Pre warm Transmitter On Anyone MUST pass through Pre warm from either warm or cold Control System active are powered invited WiND personnel sites with the intention of flying 100 Hot and Gate Zones Once on location at a test site the area being used for testing must be divided up to give safe zones and danger zones for WIND personnel as well as spectators AMA fields will have similar zones already in place and marked In the event that the test is being conducted outside an AMA field here is a description of how to define these zones Defining the Hot Z
112. e to successfully tune the control loops and navigate between waypoints given from a Python Script similar to how the onboard autopilot will be receiving waypoints from the software team s higher level board A complete result on the Simulation is in the Autopilot results section We also only gave ourselves a half smiley on being capable of supplying 102 watts of power to the on board electronics because while we fully designed power board capable of supplying the necessary voltage it was never printed due to time and budget constraints 89 The camera gimbal was not fully utilized because the software team was unable to get the Sony block camera working with their systems So we didn t fully install the pan tilt system 8 Conclusion and Recommendations Project WiND has made great strides towards the ultimate goal of creating a multi UAV system for use in search and rescue The UAV Robin has successfully flown under AUTO1 however suffered serious damage during a crash on April 11 2012 and therefore is currently grounded indefinitely as a result Jay has flown under radio control and Duck is a few parts short of an RC flight The autopilot boards are successfully connecting and communicating to a laptop over the Xbee radios and multiple autopilot boards can connect to the same laptop simultaneously and stream data to the ground control software console on the laptop We can also simulate multiple UAVs on different flight paths in the
113. e to the great outdoors Others are serious hikers who are exhilarated by the danger and challenges presented by attempting to climb a 4000 foot tall mountain Unfortunately each year thousands of people in the US get lost or injured while hiking and must be rescued by professional search and rescue teams In fact just in America s National parks from 1992 to 2007 there were 78 488 individuals involved in 65 439 search and rescue incidents Heggie et al 2009 Of these 3 39 ended up in fatalities and 30 94 in personal injuries to the victim as visualized in Figure 1 Search and Rescue Operations Outcomes 1992 2007 3 39 E Fatalities E Unharmed E Injured Figure 1 This graph illustrates the breakdown of fatalities vs injuries vs unharmed survivors in all search and rescue operations in the United States from 1992 2007 Heggie et al 2009 Figure 1 illustrates that only a small fraction of the victims in need of search and rescue perish as a result of being lost but experts say that this number would be closer to a 20 fatality rate without the presence and quick response of search and rescue teams Heggie et al 2009 This clearly shows from the victim s perspective the need for fast and accurate search and rescue efforts in our national parks and beyond From the perspective of the rescue teams the challenges and risk to the rescuers are great as well Musculoskeletal injuries were the most common type of inj
114. eactions after sending different commands to the autopilot See Appendix G User Manual Airframe Simulation for instructions on how to run simulations for more details 3 2 4 1 Reading Simulation Data 63 Providing that the server program was running without the n flag the data is stored within paparazzi var logs titled with a date tag from when the simulation was started The messages stored in the data are defined in the telemetry configuration file Each message has a time stamp and an aircraft id appended to the beginning Figure 76 is an example of a GPS message Id Mode UTM North Altitude Climb itow gps_nb_err T 3 pi 3 TI 469325200 T 0 i 16 331850239 i 2 Time Stamp Type UTM_ East Course Speed week utm zone Figure 76 GPS Message Structure The GPS messages from simulations contain the position of the aircraft which was used to examine the effect of changing the parameters of the control loops The firmware for the GPS and the paparazzi system works with a GPS positioning protocol known as Universal Transverse Mercator UTM UTM involves separating the Earth into 60 zones where each has an origin Worcester is located in zone 18 and the Tanner Hiller Airport is located at 73 627 587 meters east and 469 325 200 meters north of the origin of the zone 3 2 4 2 Control Loop Simulations Before beginning run simulations on the paparazzi system s control loops a basic understanding of the controls behind UAVs was researched T
115. ectly next to the first field which is the time stamp relative to the start of the test in seconds 3 3 5 Auto 1 After several successful RC flights on Robin through both RC control and Manual mode of the autopilot the team engaged Auto 1 mode during a straight pass down the runway When engaged the plane banked to the right slightly Due to an unfastened downlink antenna and lack of notice we do not 82 possess telemetry data or footage of our Auto 1 test Since we were only able to engage Auto1 once without calibrating the airframe and with data collection of the event the goal was considered partially met 3 3 6 Auto 2 The overall goal for the system was to provide a system which flown between separate GPS waypoint s This required a fully calibrated Auto1 for stabilized flight Without Auto 1 testing we were unable to meet our goal of flying the plane in Auto 2 4 Timeline The original timeline created for the project is depicted in figure 97 in the form of a Gantt chart This turned out to be a very optimistic timeline and most of the milestone deadlines ended up being missed B term week of C term week of deliverables 24 Oct 31 Oct 7 Nov 14 Nov 21 Nov 28 Nov 5 Dec 12 Dec Break 9 Jan 16 Jan 23 Jan 30 Jan 6 Feb 13 Feb 20 Feb 27 Feb Break Testing One drone flying under RC control Two drones flying under RC control Three Drones fly under RC control es One drone flying under Autopilot control SE Two drones flying un
116. ed down as the plane approached the next waypoint When kp was increased from 3400 to 1000 the system demonstrated an under damped response when changing waypoints and circling waypoints The original and default kp generated the best response and will be used for autonomous flights Figure 89 shows the end result of the waypoint navigation simulation m GCS ei ey a Nav Maps Help TelemasterTest a wass4 e 42 357629 72 136407 1 01 ha IK 00 03 39 000m ROSE Standby2 Nav 15 40 38 TelemasterTest Geo ir Bat Status AGL Block 15 40 38 TelemasterTest AUTO Z Time 01 35 Flight Plan GPS PFD Misc Setti Stage 01 35 e 15 A0 47 TelemasterTest Holdir ETA nue v Blacks 15 41 56 TelemasterTest Takeo klech Wait GPS 15 42 20 TelemasterTest Stand 15 44 04 TelemasterTest Stand Target Alt gt block Geo init Om 75m 75m gt block Holding point A Te Loiter Cruise Dash Takeoff gt block Standby Standby2 i Figure 89 Waypoint Navigation Simulation The goal of this simulation was to examine the effect of changing the roll_attitude_gain on waypoint navigation When the plane was stable circling the standby waypoint the target waypoint was moved down the runway 73 3 2 4 3 Adding Flight gear for visualization An option that can be added to the paparazzi simulations is Flight Gear Flight Gear is an open source remote control plane simulator Adding Flight Gear to p
117. eels with new wheels Added New decoder board Plane pulled to the right during stable flight Lost the down link before going into Auto 1 Feb 18 New decoder board Fixed all crash damage o interprets signals differently Installed the dome Caught a cross wind and Calibrated new decoder board erashed Replaced glue on tail Apr 7 Jay Too windy taxi test only Flight Auto 1 2 Apr 11 Jay Jay flew slight warp in right To be continued Flight wing discovered Auto 1 2 Only Half of Robin returned After the first flight a redesigned of the internal layout of Robin was completed With the new layout the gas tank was moved aft by about 4 inches This helped to stabilize the location of the center of gravity while still keeping it in a good location with respect to the engine The engine in the new location can be seen in Figure 40 Old New Location 4 inches Location Figure 40 Gas tank in its final position moved 4 inches back Moving the gas tank aft allowed the throttle servo to be relocated closer to the engine For the first flight the throttle servo was mounted behind the tank and ran a thin push rood above the tank to the engine This didn t work well because it didn t have a direct path to the engine so some bends were added in the wire which caused it to flex giving it some problems With the servo installed in between the engine and the gas tank it had a more direct route and made debugging the engine pro
118. enerator to the error amplifier output voltage at the COMP pin The same error amplifier is used for operation in buck and buck boost mode V A i ton Buck 5 yA x Vin Vout 50 pA x Cramp Buck Boost 5 pA x Vin 50 pA IL Emulated p H Cramp Ramp Pedestal Level 10 x Rs volts amp 30058525 FIGURE 9 Composition of Emulated Current Signal Ramp Generator The ramp signal of a pulse width modulator with current mode control is typically derived directly from the buck switch drain current This switch current corresponds to the positive slope portion of the inductor current signal Using this signal for the PWM ramp simplifies the control loop transfer function to a single pole response and provides inherent input voltage feed forward compensation The disadvantage of using the buck switch current signal for PWM control is the large leading edge spike due to circuit parasitics The leading edge spike must be filtered or blanked to avoid early termination of the PWM pulse Also the current measurement may introduce significant propagation delays The filtering blanking time and propagation delay limit the minimal achievable pulse width In applications where the input voltage may be rela tively large in comparison to the output voltage controlling a small pulse width is necessary for regulation The LM5118 utilizes a unique ramp generator which does not actually measure the buck switch current but instead creates a
119. errorism armed attacks US Air Force Will be commonly employed in search and 2012 rescue missions The great benefit of these drones is that they will allow a great amount of area to be searched in little time with a small amount of man power all while keeping rescuers safe 1 4 Project Division This project was committed to filling the need of search and rescue operations by providing a system that will successfully search large areas on the order of tens of square miles in a small amount of time on the order of hours without putting human rescuers in harm s way Designated Project WIND the main project has these lofty goals To make this more manageable the project was divided into three sub projects at Worcester Polytechnic Institute WPI and two additional projects at the University of New Hampshire UNH The three WPI projects included the software development team the communications team and the platform design team The UNH teams were a human interface design team and a second communications team with a focus on the radio hardware Figure 4 is the project organization flow chart which visualizes the team organization and how the five teams will interact Software Platform Team UNH Multitouch Interface Team Se ee ee ee ee ee ee ee ee e Hardware O Software Comms Interface Interface d Comms and i i BEEN I Ground Control t m Hardware Platform b 4 Networked Automated
120. first plane by using the airframe selection of the left Select build target to be Sim Run make Then select simulation under execution then hit connect Ge a ae The GCS and the mni Simulator window will now pop up simply mimize them and return to the paparazzi launcher and select the second airframe o gt Make and then execute in the same fashion 7 Nowa second GCS window and simulator will pop up except this GCS window will contain both planes that were executed The GCS should look similar to the image below Radio Controller Interface Paparazzi autopilots provide a radio controller interface system for manual override of the UAV during flight This is a critical safety feature for the autopilot and also required by FAA regulations The autopilot expects a pulse position modulation PPM from a radio controller s receiver The radio configuration file located in paparazzi conf radios defines each of the channels and the time ranges for each Some systems currently use a PPM communication system and it s as simple as wiring the receiver s PPM line to the R C PPMIN pin on the autopilot board Unfortunately not all systems utilize PPM or the PPM trace is difficult to access in the receiver 123 The MeekPE encoder an open source PPM encoder board provides a solution by taking the servo channels and mixing them into a PPM signal This allows for a PPM to be generated from any style of receiver system and without
121. for search and rescue All UAVs in the system utilize the paparazzi autopilot system which is an open source Linux based autopilot package for flight stability and autonomous control The system was engineered to follow a centralized command structure revolving around a specially outfitted UAV the mothership The mothership communicates with the other UAVs communicating supervisory tasks and coordinating the efforts of the UAVs to be as efficient as possible The mothership also communicates with the ground station where rescuers on the ground can relay commands to the network and vital information can be passed down from the UAVs To date we have accomplished RC flight of the mothership as well as an assisted autopilot flight of one of the drone models where the autopilot was given control of the roll and the pitch while the pilot maintained control of the rudder and the throttle Executive Summary The purpose of the executive summary is to allow it to serve as both an executive summary as well as an easy entry for future conference papers Design of an Autonomous Platform for Search and Rescue UAV Networks Catherine Coleman Joseph Funk James Salvati Chris Whipple Taskin Padir Alexander Wyglinski Worcester Polytechnic Institute 100 Institute Rd Worcester MA 01609 projectwind wpi edu ABSTRACT This project designed and implemented a platform for use in a system of unmanned aerial vehicles UAVs capable of human assisted
122. getting a fully autonomous UAV was to create a stable platform The first Airframe we flew was Robin the red telemaster We flew Robin on November 13 and February 2 9 15 and 18 These flights gave us valuable information about the condition of the airframe and its stability After every flight we made necessary adjustments to the airframe to help it fly better November 13 flight Accompanying us on our first flight was Mr Gammon our engine and RC expert After a few short successful flights we discovered that we had excessive right thrust that resulted in a pull to the right during full power climbs We also found that it needed more down thrust because it had excessive climb in altitude at full power We fixed this for our next flight by tilting the engine down two more degrees and two more degrees to the right We also found that our linkage for the throttle was off and created a non linear response The engine was also idling too high and running excessively rich on the high end of rom which was fixed by adjusting the mixing and idol screws on site During our final flight that day the engine stalled which we latter found was caused by a kink in the fuel line Mr Gammon also recommended that we pressurize the gas tank with the exhaust from the muffler for the next flight Our rudder and elevator horns were also put on backwards for this flight which was fixed for the next flight Lastly we determined that the current servo being used
123. hat the system is stable and Xe Ye gt 0 as t gt 0 since V is positive definite while its derivative is negative definite This is tracking control law is a continuous static control law and simply describes a simply control theorem to UAVs Using the GPS messages from the simulation the team was able to simulate different responses from the control system after modifying PID constants for various control loops of the autopilot The paparazzi autopilot control system can be summarized by the flow chart in figure 77 Horizontal Control Autopilot Navigation Flight Plan Servos Vertical Control Pitch Loop Throttle Loop Figure 77 Paparazzi Autopilot Control Loop Structure The overall structure features two main control loops one for vertical and one for horizontal where the final output of each control loop define target positions for the control surfaces driven by the servos Altitude Loop The flight plan contains different navigation routines which guide the autopilot through various target coordinates Some navigation routines such as standby only contain one target waypoint and a set circling radius for that waypoint A waypoint contains target positions which set target positions for the horizontal control loop and the vertical control loop Vertical Control Loop The vertical control is in charge of reaching target altitudes by controlling the target position of the elevator and the throttle of the eng
124. he default values for airspeed ground speed throttle and pitch The vertical control section also contains the values for the proportional and integral gains for the vertical control loop Since these values are contained within the configuration file they will be easier to adjust The horizontal control section contains limits for roll and pitch and their corresponding proportional and differential gains The settings configuration file allows for the modification of these variables during runtime from the ground control station which proved useful for tuning the control characteristics of the UAV during flight 3 2 3 2 Telemetry The telemetry configuration file defines the messages used for plane to base station communications All of the messages within the telemetry are transmitted by the UAV and then displayed at the ground station within the messages window This allows for debugging the control system and its various subsystems on the ground and during flight All messages are saved for review 55 after the flight Each type of message has a period defined This allows for less important messages to be slowed down reducing data transmission lt message name ATRSPEED period 1 gt lt message name ALIVE period 5 gt lt message name GPS period 0 25 gt lt message name NAVIGATION period L2 s lt message name ATTITUDE period 0 5 gt lt message name ESTIMATOR period 0 5 gt lt message name ENERGY ES
125. he following controls equations are based on the article by Chang Boon Low in A Trajectory Tracking Control Design for Fixed wing Unmanned Aerial Vehicles The state variables used in our control loops are Heading Velocity these variables correspond to the servo position and the output variables in our control loops A complete description of how each of these effect the motion of the airplane can be found in the Platform Background How to Fly section A general UAV kinematic equation of the motion can be modeled as x V coso y V x sino Where x and y represents the position represents heading and V represents velocity Variables with the subscript e are error terms Variables with the subscript r are target variables The tracking error that we want to stabilize in our Control equations is Xe cosm sing Olf r gt x Ye sing cosg Oil N Pe 0 0 11 LPr P By differentiating this equation next the following tracking error model given that w is equal to the angular velocity was obtained Xe WYe V V COS Pe Ye WXe V sin Pe Pe Wr W 64 With V x y the derivative along the following tracking error model can be solved to get V XelWYe V V COS Pe Vo wx V sin Pe Then by choosing V k x V cos and pe tan t kyye where k gt 0 and ky gt 0 V becomes negative definite By applying Lyapunov stability theorem we can conclude t
126. he steps the autopilot will follow and will not proceed based on the conditional statements For example the first step in a flight plan is Wait GPS The flight plan can also be used to add additional navigation routines lt block name Wait GPS gt lt set value 1 var kill throttle gt lt while cond GpsFixValid gt lt block gt Figure 73 Wait GPS block within flight plan This is an example of programmable blocks or steps within the flight plan This example will run at the beginning of AUTO2 and until the GPS fix is valid Strip Datt ton Line wo 1 2 SCEIP Dune TEE lt Gall fun nav laine Imit gt lt call fun nav_ line WP 1 WP 2 nav radius gt lt block gt lt block group extra pattern name Survey 1 S2 Figure 74 Line navigation routine callback button This block within the flight plan configuration file creates a function callback to the line navigation routine 62 The code within Figure 74 will add a button to the control strip within the ground control station in which it calls the navigation routine nav_line The function takes in two waypoints and a circle radius This will have the UAV fly in a straight line through waypoints 1 and 2 and then perform a U turn with the given radius 3 2 3 6 Settings The settings configuration file allowed us to change values during flight time for numerous subsystems This expedited the testing process as it allowed us to change flight parameters fr
127. here was an operator on the radio controller ready to switch the UAV into manual mode and safely land the UAV Autopilot Navigating to Way Points Once the team was thoroughly satisfied with the stabilization of the UAV during Auto 1 the team proceeded to use the full autopilot with Auto 2 When Auto 2 is enabled during flight the UAV will begin navigating the current command transmitted from the ground station The default is to circle the standby waypoint defined within the flight plan Circling will allow us to determine how stable the UAV is during turns as the radius of the circling can be adjusted Once the UAV is circling the waypoint in an acceptable manner the final test will be the straight line navigation routine which would have the UAV navigate between two waypoints in a straight line with a U turn after reaching the second point Navigating between GPS coordinates was never achieved 3 3 Autopilot Results Using the open source paparazzi autopilot control system the team was able to succeed or fail in the following tasks Table 9 Autopilot goals This table lays out the autopilot goals and whether they were achieved partially achieved or not met Goals Achieved Partially Achieved Not Achieved _ Data Acquisition 3 Muttiplane Connestion x ooo ooo tege Insertion From External Source 3 3 1 Sensor Implementation 11 For use with the autopilot control software the GPS and the IR thermopiles were calibrated and i
128. his is the source of power Electric motors rely on batteries that are heavy A typical setup would provide a flight time of around fifteen minutes This flight time can be extended with more batteries which are expensive and heavy Glow Glow engines use a high octane fuel These systems can be set up to give long flight times and the engine itself is simple cheap and has a high power to weight ratio However the fuel for these engines is highly flammable and very expensive The current cost for Nitro the fuel used in these engines is around 35 dollars a gallon These engines are better suited for smaller scale aircrafts Also due to the nature of how these engines works starting these engines on an airplane is rather dangerous It requires someone to reach over the cylinder head and remove the glow plug igniter which is about six inches from a fast moving propeller which can easily remove a finger Gas Gas powered RC airplanes use a conventional 2 stroke motor very similar to the ones found in small gas power yard equipment This style of motor is simple and very reliable These engines do require some care and maintenance in the setup and operation It uses 93 octane gasoline from any fuel pump with a 30 1 2 cycle oil mixture which is relatively cheaper than Nitro The initial cost of the engine is more expensive than a glow engine however the long term cost is cheaper than glow 2 1 3 Basics of Flying Remote Control flying is a uni
129. hurGolnik shtml Barnard Microsystems Limited 2012 High Energy Light Weight Batteries first Online Available http www barnardmicrosystems com L4E_batteries htm Isidor Buchmann 2012 What s the Best Battery first Online Available http oatteryuniversity com learn article whats the best battery University of Alberta 2011 September Alberta UASGroup first online Available http paparazzi enac fr wiki UAlberta_ UASGrou Autopilot Research Images http www cloudcaptech com piccolo II shtm http diydrones com page autopilots 1 http paparazzi enac fr wiki File Ir response curve gif Sources Am Cho Jihoon Kim Sanghyo Lee Sujin Choi Boram Lee Bosung Kim Noha Park Dongkeon Kim Changdon Kee 2007 Oct Fully automatic taxiing takeoff and landing of a UAV using a single antenna GPS receiver only Control Automation and Systems 2007 ICCAS 07 International Conference on Online vol no pp 821 825 17 20 doi 10 1109 ICCAS 2007 4407014 Available http ieeexplore ieee org stamp stamp jsp tp amp arnumber 4407014 amp isnumber 4406493 Abdelkrim N Aouf N Tsourdos A White B 2008 June Robust nonlinear filtering for INS GPS UAV localization Control and Automation 2008 16th Mediterranean Conference online vol no pp 695 702 25 27 doi 10 1109 MED 2008 4602149 95 Available bn ieeexplore ieee org stamp stamp jsp tp amp arnumber 4602149 amp isnumber 4601965 Al
130. iently They also were responsible for creating the image processing and data processing necessary to limit the amount of unnecessary data being sent back to the rescuers on the ground The communications team was responsible for creating a resilient wireless link between all of the UAVs in the network as well as a link from the network to the ground station This report represents the last team which is responsible for the design and manufacturing of the platform 2 DESIGN SPECIFICATIONS To accomplish these lofty goals several design specifications were established based on existing research and the needs of the other teams working on this project The list of design specifications included e Three fully autonomous fixed wing aircraft e Interface with the UAV controlling search algorithm e Autonomous navigation based on GPS waypoint navigation The aircraft will need to be able to receive GPS coordinates from the search algorithm and then proceed to fly to the given coordinate then circle awaiting for new GPS waypoints e Each UAV will need to carry a payload of 10 lbs in order to carry all of the processors cameras flight sensors and gimbal e Capable of flying at a cruising speed of 35 45 miles per hour under full load of search and rescue sensors e Capable of flying between 120 ft and 400 ft of altitude as specified by the FAA for UAVs e Capable of maintaining flight without refueling for a minimum of 1 hour e Capa
131. ifier configuration section For the design example the inductor values in both modes are calculated as Vout Vm Vout L1 Buck Mode Vint X f X loppg V V ppa A Wout __ick Boost Mode Vout Vinz X f X IRippLe Where Vout S the output voltage Vun is the maximum input voltage f is the switching frequency Lupp S the selected inductor peak to peak ripple current 1 2 A selected for this example Vino is the minimum input voltage The resulting inductor values are L1 28 uH Buck Mode L1 9 8 uH Buck Boost mode A 10 uH inductor was selected which is a compromise be tween these values while favoring the buck boost mode As will be illustrated in the compensation section below the in ductor value should be as low as possible to move the buck boost right half plane zero to a higher frequency The ripple current is then rechecked with the selected inductor value us ing the equations above IRIPPLE BUCK 3 36A RIPPLE BUCK BOOST 1 17A 17 Because the inductor selected is lower than calculated for the Buck mode the minimum load current for CCM in buck mode is 1 68 A at maximum VIN With a 10 uH inductor the worst case peak inductor currents can be estimated for each case assuming a 20 inductor value tolerance lour IRIPPLE Ss Ek Buck Mode 0 8 l4 PEAK Vout Vin lou 0 8 x Vino IRIPPLE lo PEAK Buck Boost Mode For this example the two equations yield PEAK 9 43A lo
132. igure 65 Above is an example of the messages window provided by the ground station to view incoming messages from the UAV The bat message is currently selected and shows values such as voltage and current from the baten 57 Figure 66 Above is a sample data file collected during tested The messages above were selected by the telemetry file and then recorded when received from the UAV sssssssssessenssrsssnrnrrnsrrerresnnn 57 Figure 67 The top and the bottom of the MeekPe encoder board This encoder board allows us to read the commands for the servo channels from the radio receiver without modifying it 58 Figure 68 MeekPe PPM Encoder board block diagram The encoder board takes in all of the servo commands and then sums them together into a PPM signal which is easy to parse using the DapalazZi TAGIO COMMOUPATION EE 59 Figure 69 Radio Control System for controlling the plane through the autopilot system 60 Figure 70 Radio Configuration File This file defines the structure of the PPM signal received from ine MeekPe encoder board we scacensecssoncesenscennaegenaeedensnensacdiwanadenevannd seenabadle etecbuaediasbauxuceamnasbdeeuadeeanes ts 60 Figure 71 Waypoint Definitions within flight plan These waypoints are example waypoints contained within the flight plan The waypoints position is relative in meters from the home NN e Le EE 61 Figure 72 Visualization of the flight plan over Tanner Hiller the lo
133. il The tail is a combination of balsa wood and foam Since this plane had only a 6 ft wingspan and didn t need to have a long flight time a brushless DC motor was purchased to power it After Goose was fully assembled it was determined that it was slightly tail heavy and needed additional counterweights in the nose to balance correctly for flight Figure 15 Fully assembled Goose ready for flight Designing and building Goose was a 3 month learning experience In the end the team decided that buying partially assembled RC airframes would be a better decision for this project The scope of the project was on creating UAV s capable of preforming search and rescue missions not on building airplanes 2 2 3 Parts Selection With the background experience from completing goose the team needed to choose appropriate hardware for our drones This next section will discuss our selection process for the necessary components Airframe Our airframe selection was one of the most important decisions that the team made The airframe determines the size and type of engine that can be used It also determines the max weight and volume of the payload This payload includes the fuel all of our electronics cameras and communication hardware The type of airframe chosen had an effect on its flight speed maneuverability and sensitivity to commands All of these factors were considered in airframe Selection 17 For the first drone the team selected
134. in VIN and VCC Internal Enable Signal l 30058516 FIGURE 6 VIN and VCC Sequencing Enable The LM5118 contains an enable function which provides a very low input current shutdown mode If the EN pin is pulled below 0 5V the regulator enters shutdown mode drawing less than 10 pA from the VIN pin Raising the EN input above 3V returns the regulator to normal operation The EN pin can be tied directly to the VIN pin if this function is not needed It must not be left floating A 1 MQ pull up resistor to VIN can be used to interface with an open collector or open drain con trol signal UVLO An under voltage lockout pin is provided to disable the regu lator when the input is below the desired operating range If the UVLO pin is below 1 13V the regulator enters a standby mode with the outputs disabled but with VCC regulator op erating If the UVLO input exceeds 1 23V the regulator will resume normal operation A voltage divider from the input to ground can be used to set a VIN threshold to disable the reg ulator in brown out conditions or for low input faults If a current limit fault exists for more than 256 clock cycles the regulator will enter a hiccup mode of current limiting and the UVLO pin will be pulled low by an internal switch This switch turns off when the UVLO pin approaches ground po tential allowing the UVLO pin to rise A capacitor connected to the UVLO pin will delay the return to a normal operating
135. in including polyester epoxy and vinyl Polyester is the cheapest type and hardens the fastest Unfortunately it is not appropriate for high 13 strength applications and shrinks over time which makes it the least suitable for aircraft construction Epoxy is the strongest and lightest resin of the three however it needs a skin protection because it is heat sensitive Its varying drying times can also make it difficult to work with Vinyl resin which is a cross between polyester and epoxy has the best properties of both materials It is both strong and flexible It also doesn t have any moisture issues like the epoxies Like the Polyester material it is easy to use inexpensive and fast drying The only negative to this option is that it requires precise mixing and can result in an explosive solution When creating a composite aircraft the first step is to mold the core material into the desired shape Next wrap it in the reinforcement material then cover the reinforcement material with the resin until it is thoroughly saturated Honus 2009 2 1 2 Propulsion The three primary power sources for propulsion used in modern aircrafts of this size is electric motors gas engines and glow engines All of these systems have their own advantages and disadvantages and would work for our situation Electric Using an electric motor to power an airframe allows for an easy simple solution that requires minimal maintenance The biggest downside to t
136. in the orange Yellow The rest of the Hot Zone as defined above The rules for the hot zone apply Defining the Safe Zone Once the runway has been defined the Flight Controller in coordination with the ground controller needs to define the safe zone This is where all personnel and any spectators with the exception of the flight controller will stand while the robot is declared hot See declaration of Robot stages for explanation or in the air It is important to think about the direction of flight intended for the robots If they are headed 101 to points north of the runway hot zone then the safe zone should be to the south of the hot zone in order to minimize robots flying over the safe zone AMA Academy of Model Aeronautics fields will have this area marked already The Safety Positions for Single Robot Testing 1 The Flight Controller Whenever a robot leaves the ground a flight controller must be standing by with an RC override switch on an RC module prepared to take control from the auto pilot in the event of an in flight emergency The flight controller is the lead safety person on the field at all times What he she says goes for everyone involved The flight controller is required to A B C D E F G Be a card carrying member of AMA Academy of Model Aeronautics Lead project WiND in determining a good location for tests as well as defining a flight plan as defined in the section Explanation
137. ine Available http dynamicslab mpe nus edu sg dynamics thesis1011 UAV 20Autopilot pdf Jung D Levy E J Zhou D Fink R Moshe J Earl A Tsiotras P 2005 Dec Design and Development of a Low Cost Test Bed for Undergraduate Education in UAVs Decision and Control 2005 and 2005 European Control Conference CDC ECC 05 44th IEEE Conference online vol no pp 2739 2744 12 15 doi 10 1109 CDC 2005 1582577 Available http ieeexplore ieee org stamp stamp jsp tp Sarnumber 1582577 amp isnumber 33412 Kabbabe Kristopher 2011 Development of Procedures for Flight Testing UAVs using the ArduPilot System online Available http uavs mace manchester ac uk uploads Research MScKabbabe2011 pdf 97 Kim Jong Hyuk Sukkarieh Salah Wishart Stuart 2006 Real Time Navigation Guidance and Control of a UAV Using Low Cost Sensors Springer Tracts in Advance Robotics online vol 24 pp 299 309 2006 DOI 10 1007 10991459 29 Available http www springerlink com content h548798460354551 Metni Najib Pflimlin Jean Michel Hamel Tarek Soueres Philippe 2006 December Attitude and gyro bias estimation for a VTOL UAV Control Engineering Practice online vol 14 is 12 pp 1511 1520 Available http www sciencedirect com science article pii S096706610600030X Reuder Joachim Brisset Pascal Jonassen Marius Muller Martin Mayer Stephanie 2009 April The Small Unm
138. ine as both have an effect on controlling the altitude of the plane The vertical control loop is broken down by the flow chart in figure 78 65 Navigation Roll Loop E Course Loop T Flight Plan Y A Vertical Control FP Pitch Loop Throttle Loop Altitude Loop Climb Loop Figure 78 Vertical Control Loop The vertical control loop s input is the target altitude The target altitude is fed through two separate control loops which control the throttle of the plane and the pitch of the plane Both the throttle and the pitch can affect the change in altitude of the plane First the team simulated the effect of changing the derivative constant of the pitch control loop to examine its effect on the takeoff of the plane during the simulation The pitch control loop is depicted below in figure 79 CH auto _pitch_kd ctlauto_pitch_ki j Lis nay pitch climb_ setpoint av Di Estimator z Figure 79 Pitch Control Loop The output of the climb control loop is the climb_point which defines the target climb point The climb_setpoint is the input to both the throttle control loop and the pitch loop seen above The structure of the pitch control loop contains proportional integral and derivative terms which are summated into the resulting nav_pitch which is limited by defined bounds Nav_pitch is the desired pitch of the plane during flight The plane s altitude is continuously calculated by the estimator
139. ing power to lift them the space to contain them and the electrical power to operate them Table 4 shows exactly what the platforms are prepared planned for by airframe Even if the opportunity was never realized during this project to implement all of these specifications the ground work has been laid out for future teams to utilize particularly for integration between the teams For example the final Layout for balancing for all three airframes in all configurations were not completed during this project however the layouts were complete in CAD illustrating that the groundwork is ready to be implemented 39 Table 4 Shows the different types of support that the team completed preparations for on the different airplanes pn nu ng Camera Support x x x x x x x rAlsystem Support X x x x xx k ae Table 5 shows which of the following types of support demonstrated during at least one of the test runs Table 5 Shows the different types of support that were Implemented on the different airplanes Sein RCfiga FX XK XK XE S S AutopilotSupport_ x x x o Cameras x x III Appen 3 3 II III comms Support II III Flight Data from GPS Utilizing the GPS graphs were made of our altitude and inferred velocity during all of the flights that data was recorded During the tests an average speed of 40 miles per hour was achieved which falls within the design specifications Figure 47 shows the different
140. ing the sagety thang where applicable must have an inspector and pull test pror to fying 2 The pull test will be in accordance wih the current Competiion Reguiations sor the applicable model arcraft caiegory 3 Model aircraft not filling a specie category shall use those pulliest requirements as indicated for Control Line Precision Aerobatics A The fying area musi be clear of all uility wres or poles and a model arcraft will not be Brown closer fan 50 feet to any above ground ele cine wiiity lines The fying area must be clear of all nonessential participants amd spectators before the engine is started 110 Academy of Model Aeronautics ic se SE SC SE W s El AMA BCALERT OI WEL BEROR RTES How to file an insurance claim eee EE actions to the member club officer and or Contest Director if the BE Se ee al 2 ee ee T en II ation BEE ry or excess msurance So m addition to notifying AMA Headquarters of the riki ie tee aa AMA eee ee a r i a a him or her 1 e homeowners renters automobile health insurance etc If the prmary insurance covers the total summer because this 1s our peak tme for claims CLC Lamm are processed as quickly as possible Se a e a a no ee ee sala ieee Tale amp Vandalism geen pi EE ryers Final decisions on what is covered and how much is paid are made by an independent Third Party Er ars receive up to three types of insurance coverage with their me
141. initions of the RC commands during AUTOI1 gt lt set command THROTTLE value THROTTLE gt lt set command Y AW value Y AW gt lt auto_rc_commands gt To test throttle during AUTOI the command has to be removed from this section so that the autopilot has full control over the throttle To confirm that the command laws were defined properly set up the plane with the autopilot and all of the control surfaces plugged in their corresponding channels When the autopilot is turned on and the radio switched into MANUAL mode all of the control surfaces should react to the radio controller When switched into AUTO1 the plane should start attempting to stabilize itself Note If indoors and using the IR Thermopile system the control surfaces may act erratically Make sure the vertical sensor sees ground using your hand In AUTO the user should still have control over the ailerons elevator and then any of the surfaces defined in the auto_rc_commands section In AUTOZ2 the user should not have any control over the control surfaces Three Switch Position Setup A three position switch needs to be dedicated to change the mode of the autopilot Manual AUTOI AUTO2 We used a Spektrum dx6i which did not provide any three position switches An alternative solution was to mix the gear switch with the AUX1 switch so that one switch selected autopilot or manual mode and then the AUX1 switch selected AUTOI or AUTO This channel was then mixe
142. integration a camera was mounted in Robin as well as its supporting hardware to record video Figure 45 shows its set up in the plane inside the dome Since a camera was installed for this flight and the it was recording the software team requested a few fly overs to capture images of people on the ground while still under RC control before testing the autopilot Figure 45 Camera behind Robin s dome before its April 11th flight At the end of these passes control of the elevator was lost and it flew into some trees The team was able to recover the engine all of the electronics and three of the servos The tail right wing and the landing gear were not found after this incident Figure 46 shows what was left of the fuselage after the crash 38 Figure 46 What was left of Robin s body after the April 11th Flight All of the electronics survived the crash Robin s airframe is currently beyond repair and it will have to be replaced before any future flights 2 4 Platform Results This section describes how well the team met its design specifications for the platform These results also include how well the gimbal did at dampening the vibrations to the camera Completing Platform Goals The goals for a platform team at the beginning of the project where to develop three planes modified to support autopilot camera systems AI systems and radio communication Support is defined as having proven that plane we made to have the lift
143. ion is dedicated to covering the background the approached used testing and results for the platform development 2 1 Background Before attempting this project the team needed a though understanding of the current state of the art for designing building powering and flying scaled planes Additional solutions were researched including buying kit RC planes to manufacturing a custom solutions This background information heavily influenced our final decisions 2 1 1 Airplanes An airplane is only as good as its airframe The airframe determines how well it will fly and restricts its speed and flight time Having a good airframe with an appropriate shape for our project is an important first step In the following section the different types of airframes are discussed in addition to the basics of aircraft design and construction Types There are many styles of airplanes each one has its own advantages and disadvantages Using the correct style planes in this project can make both performing search and rescue patterns easier and collecting visual information simpler Trainers are specifically designed for beginners They are usually larger models made from balsa wood with the wings mounted high on the body Carperner 2002 They usually fly slowly and will return to straight flight level flight when not being directed Tower 1994 Scale models recreate full size models These are for advanced RC builders and flies and are difficult to a
144. it can be designed to have exactly what would be needed This option would be the best for the team in the long run though would take the longest time to complete Ordering a Papparazzi developed board would be the most expensive solution though would guarantee that the autopilot will compile on the board and have at least the minimal requirements for flight Our decision matrix for autopilot boards was weighted based on the following criteria Value how expensive 1 Expensive 5 Least Expensive Versatility how adaptable the controller is 1 Less adaptable 5 More adaptable Availability are the boards currently available 1 Unavailable 5 Available Implementation amount of work for implementation with paparazzi 1 More Work 5 Ready Table 7 Decision between using a paparazzi autopilot board verses using a development board Board Board O a a 4 49 Based on the results it was decided to order a Paparazzi developed board as it will be readily available and is known to work for our application where a development board will require more research to determine the best fit Once it was decided that the team would be working with a Paparazzi developed board it was narrowed down to three Paparazzi boards based on their current availability Table 4 shows the three optional boards and their specifications Based on this chart the team decided on the YAPA 2 It was chosen because it featured the largest number of servos
145. ithin power ratings appropriate for the output voltage Values of 309Q for R9 and 2 67 kQ for R8 were selected R1 R3 C21 A voltage divider can be connected to the UVLO pin to seta minimum operating voltage VIN wu cn for the regulator If this feature is required the easiest approach to select the divider resistor values is to choose a value for R1 between 10 kQ and 100 kQ while observing the minimum value of R1 necessary to allow the UVLO switch to pull the UVLO pin low This value is R1 2 1000 x ViN MAX R1 2 75k in our example R3 is then calculated from R1 R3 1 23 x __ _____ Viney 5 BA x R1 1 23 Since VIN mn for our example is 5V set VIN uvLo to 4 0V for some margin in component tolerances and input ripple R1 75k is chosen since it is a standard value R3 29 332k is calculated from the equation above 29 4k was used since it is a standard value Capacitor C21 provides filtering for the divider and the off time of the hiccup duty cycle during current limit The voltage at the UVLO pin should never exceed 15V when using an ex ternal set point divider It may be necessary to clamp the UVLO pin at high input voltages Knowing the desired off time during hiccup current limit the value of C21 is given by torr RERI x Ca xin y L I RS R1 R3 Vinx R1 Notice that topp varies with Vu In this example C21 was chosen to be 0 1 F This will set the topp time to 956 us with VIN 12V
146. itor and an internal 10 pA current source set the rise time of the error amp reference The SS pin is held low when VCC is less than the VCC under voltage threshold lt 3 7V when the UVLO pin is low lt 1 23V when EN is low lt 0 5V or when thermal shutdown is active 8 FB Feedback signal from the regulated output Connect to the inverting input of the internal error amplifier ia COMP Output of the internal error amplifier The loop compensation network should be connected between COMP and the FB pin www national com 2 Pin Name Description OOOO O 16 VCC Output of the bias regulator Locally decouple to PGND using a low ESR ESL capacitor located as close to the controller as possible 17 VCCX Optional input for an externally supplied bias supply If the voltage at the VCCX pin is greater than 3 9V the internal VCC regulator is disabled and the VCC pin is internally connected to VCCX pin supply If VCCX is not used connect to AGND High side gate driver supply used in bootstrap operation The bootstrap capacitor supplies current to charge the high side MOSFET gate This capacitor should be placed as close to the controller as possible and connected between HB and HS 19 HO Buck MOSFET gate drive output Connect to the gate of the high side buck MOSFET through a short low inductance path Buck MOSFET source pin Connect to the source terminal of the high side buck MOSFET and the bootstrap Capacitor EE
147. iver circuit works in conjunction with an internal diode and an external bootstrap capacitor A 0 1 uF ceramic capacitor connected with short traces between the HB pin and HS pin is recom mended for most circuit configurations The size of the boot strap capacitor depends on the gate charge of the external FET During the off time of the buck switch the HS pin voltage is approximately 0 5V and the bootstrap capacitor is charged from VCC through the internal bootstrap diode When oper ating with a high PWM duty cycle the buck switch will be forced off each cycle for 400ns to ensure that the bootstrap capacitor is recharged Thermal Protection Internal Thermal Shutdown circuitry is provided to protect the integrated circuit in the event the maximum junction temper ature is exceeded When activated typically at 165 C the controller is forced into a low power reset state disabling the output driver and the bias regulator This protection is provid ed to prevent catastrophic failures from accidental device overheating Application Information The procedure for calculating the external components is il lustrated with the following design example The designations used in the design example correlate to the final schematic shown in Figure 18 The design specifications are e VOUT 12V e VIN 5V to 75V e F 300 kHz e Minimum load current CCM operation 600 mA e Maximum load current 3A R7 R RT sets the oscillator swi
148. jects would allow the users to fly the fleet of drones from the Microsoft Surface update waypoints and stream filtered images back from the different UAVs To accomplish this the software team needs to have an interface with the autopilot board in order to change waypoints as well as get current telemetry and location data This process has been started but an elegant solution has not been developed yet Mechanically the teams need to integrate all of the necessary hardware for each team into the UAVs including the search and rescue cameras FPGA board for image processing the Wi Fi modules the power distribution boards and the software team s logic board All of these components need to be mounted in the UAVs with a vibration resistant mounting system and wired together The layout inside the UAVs has been complete for all VI of these components with the help of CAD models of the airframes to ensure that each airframe remains balanced with the addition of all the extra weight Once these have been complete the system will be fully functional and ready to perform low altitude efficient aerial search and rescue 10 BIBLIOGRAPHY National Search and Rescue Manual Volume 1 National Search and Rescue System United States Joint Chiefs of Staff Washington De 1991 http www towage salvage com files sarO1 Heggie Travis W Amundson Michael E Dead Men Walking Search and Rescue in US National Parks Wilderness a
149. l com LM5118 Connection Diagram VIN HS UVLO HO RT HB EN VCCX RAMP VCC AGND LO SS PGND FB CSG COMP CS VOUT SYNC 30058502 Top View See NS Package Numbers MXA20A Ordering Information Ordering Number Package Type NSC Package Drawing Supplied As LM5118MH TSSOP 20EP MXA20A 73 Units Per Anti Static Tube LM5118MHX TSSOP 20EP MXA20A 2500 units shipped as Tape amp Reel Pin Descriptions Pin Name Description o 2 UVLO If the UVLO pin is below 1 23V the regulator will be in standby mode VCC regulator running switching regulator disabled When the UVLO pin exceeds 1 23V the regulator enters the normal operating mode An external voltage divider can be used to set an under voltage shutdown threshold A fixed 5 pA current is sourced out of the EN pin If a current limit condition exists for 256 consecutive switching cycles an internal switch pulls the UVLO pin to ground and then releases 3 RT The internal oscillator frequency is set with a single resistor between this pin and the AGND pin The recommended frequency range is 50 kHz to 500 kHz 4 EN If the EN pin is below 0 5V the regulator will be in a low power state drawing less than 10 pA from VIN EN must be raised above 3V for normal operation 5 RAMP Ramp control signal An external capacitor connected between this pin and the AGND pin sets the ramp slope used for emulated current mode control 6 AGND Analog ground s O 7 SS Soft Start An external capac
150. l sensors the implementation of a khalman filter can be useful for determining the location of the aircraft over the duration of the flight IMUs are used on many different unmanned aerial vehicle projects Bayraktar et al 2004 Euston et al 2008 Dobrokhodov et al 2005 Kim et al 2006 3 1 2 5 Gyroscope Gyroscopes measure changes in the UAV s rotation This can be attached to the UAV to know its pitch roll or yaw to assist with the thermopiles stabilization Although gyroscopes are contained within the IMU additional gyroscopes can provide additional accuracy over the flight duration Zhihai et al 2005 Metni et al 2006 3 2 UAV Control System Integration Once the background was research the next step was to determine which control system the team would use and the corresponding hardware to use Once the hardware and control system were selected the control system was integrated with the platform system 3 2 1 Control System Selection To determine what hardware that will be needed to fly the plane the team needed to decide on which control system to use Table 6 shows the decision matrix that was used to determine the control system The decision matrix was weighted using the following criteria which was assigned a value from 1 5 The values were assigned based on our background research and results from UAV competitions Value how expensive 1 Most 5 Least Availability how available is the autopilot including hard
151. landing After this announcement the flight controller is free to land the plane 2 The Ground Controller The ground controller will be the second in the safety hierarchy He or she will predominately control any ground based movements of both people and robots Their specific responsibilities include A B Defining the hot zone in coordination with the Flight controller See defining the hot zone for details Ensuring that all personnel and spectators abide by the hot zone and safe zone rules They must be vigilant in watching for personnel movement in the hot zone and warn any unsuspecting spectators anyone in the immediate area not affiliated with the project about the robot movements 102 C Ensure that the hot zone remains clear of people debris animals and other robots while there are robots airborne D Coordinate the landing of the robot and certify for the flight controller that the runway is clear for landing E Communicating with airport personnel in the event that a test is to be conducted at an airport or AMA field F The ground controller is the ONLY person allowed to talk to the flight controller They are to relay any messages from the flight controller who is consistently primarily focused on the robot movements to the other personnel and spectators and they will filter any communications from personnel and spectators to the Flight controllers Since the flight controller needs to remain focused on the
152. ling and is easier to break A well designed airplane compromised between having a large aspect ratio and being less maneuverable and having a low ratio that is twitchy and inefficient A good aspect ratio to aim for is 5 1 Tim 2001 y Dihedral Dihedral is an angle that raises the wing tip above wing root uai Ir w ez T Giving a plane a dihedral increases its stability and its ability to m prevent rolling However it can also add an undesired control Sine Dihedral Half Wing Span coupling Control coupling is when the airplanes tilt along an Figure 11 Diagram of how to unwanted axis when using the rudder Too little dihedral will make measure the wing dihedral turns sluggish Too much dihedral will make the wing inefficient Johnson 2007 A dihedral can be used to turn a plane without ailerons and only a rudder Washout Wings are built with a twist so that the tips are at a lower angle incident than the wings root This avoids tip stalls but also limits the planes aerobatic capabilities This also reduces structural weight These are useful in combination with high aspect ratios heavier planes and other planes not intended to perform aerobatics Aileron Flaps Ailerons are the control surfaces on the wings Ailerons are usually 10 20 of the total wing area These control surfaces are used in turning and rolls Flaps are used to change the geometry of the wing in order to increase lift This is used to allow the plane
153. m s user control interface Figure 9 was taken during the paparazzi simulation where the plane is navigating in a spiral fashion from the center point Figure 10 was taken from the software team s user interface with the outputted waypoints displayed on the left of the image 9 CONCLUSION Project WiND has made great strides towards the ultimate goal of creating a multi UAV system for use in search and rescue One of the drone models has successfully flown under assisted autopilot the mothership has flown under radio control and the second drone model is a few parts short of an RC flight The autopilot boards are successfully connecting and communicating to a laptop over the Xbee radios and multiple autopilot boards can connect to the same laptop simultaneously and stream data to the ground control software console on the laptop Multi plane simulations are also capable in the ground station software 9 1 RECOMMENDATIONS FOR FUTURE WORK There is much room for the future expansion of this project The first steps to future development need to start with finishing the assembly of the different airframes as well as the installation and calibration of the autopilot systems in each In the end the system needs at least three UAVs capable of autonomous waypoint navigation Once all of the UAVs are successfully flying under autopilot the next step would be to integrate completely with the other teams Integration with the other pro
154. m the Salely Gene musi be maintained for spectaiees a eat gen Serhan es poeta a a ET CE SALT 5 AC model aircrafl will not operaie within three 3 miles of amy pre existing fying site withoul a frequency management agreement AMA Documents 3227 Testing for RF interference 923 Frequency Management Agreement 6 With the exception of events flown under official AMA Competition Regulations excluding oke and landing mo powered model may be fown outdoors dieser than 25 feet to any individual except sor the pilot amd fhe pilots helpers located at the Aight line T Ueder no circumstances may a pioli or other person touch a model aircradt in fight while is Sill under power excepi to divert fram Striking an individual 6 AC might fying requires a lighting system providing the Pkt with a Gear view of fhe models atitude and onentabon at all times 9 The pilot of a RC model aircrafl shail fo Fly using the assistance of a Camera or First Person View FPW only in accordance with the procedures outlined in AMA Document 2550 LG FREE FLRSHT Must be at least 100 feet downwind of spectators and aupobde paring when the model aircraft is launched 2 Launch area must be clear of all individuals except mechanics officals and other fiers An effective device will be used to extinguish amy fuse on the model aincra t afer the fuse has completed its function D CONTROL LINE wie Field Layout 1 The complete control system includ
155. mbership as a benefit ledical AD amp D this coverage apples when a member myures himself or herself in a model Commercial General Liability CGL this coverage applies when a member damages someone else s roperty or mjures someone else Damage to a member ee e a liable to yourself and there is no coverage 1f a member imures someone m ns own family Fire Fandalism and Theft FIF this coverage apphes when a member s amcraft and or RC equipment 1s EPE i a Theft coverage applies only when the theft 1s from a member s locked Park Pilot members only receive liability coverage up to 500 080 as a benefit through their Park Pilot r Spe 111 Academy c of Model Aeronautics 800 435 9262 Membership Services Lmodetalrcrant o9y FLYING SITE SAFETY AND OPERATIONAL RULES The Official AMA National Model Aircraft Safety Code 1s a basic document for ALL AMA chartered clubs Every member should be familiar with the Safety Code and new members should receive instruction about this code Each club should also develop a carefully structured set of rules for their club s flying site These rules should cover two 2 areas 1 Safety rules for actual flying and 2 Operational rules which include items concerning times of operation permits required emergency numbers etc Following 1s a generic sample of a set of rules designed to supplement the required current Official AMA National Model
156. meida Pedro Bencatel Ricardo Goncalves Gil Sousa Joao 2006 Multi UAV Integration for Coordinated Missions online Available http whale fe up pt asasf images f fa Multi UAV Integration for coordinated missions pdf Almeida Pedro Bencatel Ricardo Goncalves Gil M Sousa Joao Borges Ruetz Christoph Ruetz 2007 Experimental Results on Command and Control of Unmanned Air Vehicle Systems Available http paginas fe up pt dee07011 uploads Main UAV_Command_Control pdf Bayraktar S Fainekos G E Pappas G J 2004 December Experimental cooperative control of fixed wing unmanned aerial vehicles Decision and Control 2004 CDC 43rd IEEE Conference online vol 4 no pp 4292 4298 Vol 4 14 17 doi 10 1109 CDC 2004 1429426 Available http ieeexplore ieee org stamp stamp jsp tp amp arnumber 1429426 amp isnumber 30838 Beard Randal Kingston Derek Quigley Morgan Snyder Deryl Christiansen Reed Johnson Walt McLain Timothy Goodrich Michael 2005 January Autonomous Vehicle Technologies for Small Fixed Wing UAVs Journal of Aerospace Computing Information and Communication Vol 2 Available http morse colorado edu timxb Aiaa pdf Beyeler Antoine Zufferey Jean Christophe Floreano Dario 2009 optiPilot control of take off and landing using optic flow European Micro Air Vehicle conference and competition online Available http infoscience epfl ch record
157. mp Environmental Medicine vol 20 3 pp 244 249 2009 Iserson K V Injuries to Search and Rescue Volunteers A 30 year Experience The Western journal of medicine vol 151 Iss 3 pp 352 353 09 1989 vii Table of Contents 1 INTRODUCTION P 1 Z PLAT ORM Ve VO PIT IN eege 8 KS EE E 8 E EE EE 15 GSES 61 16 EA antennae eae A ena en ea T ee a T 33 SE Ee 39 UAV CONTROLO e EE 43 DACO OU emer een ee eee a ee eee eee eee ee ee 43 BZ UAV CONEOLSVSCCIN IMETA ON ee 48 EE 77 APM EEN SE 4 1 Timeline with regards to the Hardware teognm EEN 83 42 limeline WILT regards to Integral eer 84 SAUDO E KE 84 6 INTEGRATION WITH SOFTWARE AND COMMUNICATIONS ssssssssssssseseeseesesseseeseeserseeseeesaeseuseuseuseusesesaesauseesensenseeseeansanss 85 GLENO WAY OLGA SO OV res tects tects aes antec eevee oes sce epee eee 85 Eegeregie 88 E T IE KEE 89 8 CONCLUSION AND RECOMMENDATIONS ssssssssesssssseseeseeseesesseseeseuseuseuseesesaeseeseuseuseuseeseeaesauseuseuseusesseeaesaesanseusensensensneansaneans 90 8 1 Recommendations fOr Future Development 90 d Be Te Bee TR KE 91 TOD DOG TEE 93 vill Table of Figures Figure 1 This graph illustrates the breakdown of fatalities vs injuries vs unharmed survivors in all search and rescue operations in the United States from 1992 2007 Heggie et al 2009 1 Figure 2 This is an image of rescuers performing near vertical rock climbing to locate and attend to a victim a
158. mpleted An additional damping network or input voltage clamp may be required in these cas es C20 The capacitor at the VCC pin provides noise filtering and sta bility for the VCC regulator The recommended value of C20 should be no smaller than 0 1 uF and should be a good qual ity low ESR ceramic capacitor A value of 1 uF was selected for this design C20 should be 10 x C8 If operating without VCCX then fosc X QcBuck Boost lL oap iNTERNAL must be less than the VCC current limit C8 The bootstrap capacitor between the HB and HS pins sup plies the gate current to charge the buck switch gate at turn on The recommended value of C8 is 0 1 uF to 0 47 uF and should be a good quality low ESR ceramic capacitor A value of 0 1 uF was chosen for this design C16 Css The capacitor at the SS pin determines the soft start time i e the time for the reference voltage and the output voltage to reach the final regulated value The time is determined from EIB 1 23V 10 pA and assumes a current limit gt lload ICout For this application a C16 value of 0 1 uF was chosen which corresponds to a soft start time of about 12 ms R8 R9 R8 and R9 set the output voltage level the ratio of these re sistors is calculated from R8 Vout 4 R9 1 23V For a 12V output the R8 R9 ratio calculates to 9 76 The re sistors should be chosen from standard value resistors anda good starting point is to select resistors w
159. must read and sign a liability release form from WPI This form specialized for Project WIND can be found as Appendix C in this document This is to be done before or upon arrival to the test site before the robots are unloaded from the transportation vehicle It is the responsibility of the fight controller or the chief flight controller when applicable to ensure all soectators and personnel have signed this form 5 The Pre flight Check Before a robot leaves the ground the robot must pass a thorough inspection by the project WIND team All testing is to be done while the robot is in the warm state see definition of robot states This is to be done before every takeoff even if the robot flew earlier that day The inspection includes testing A All flight control surfaces both by the manual override transmitter as well as a safety routine programmed into the autopilot if the auto pilot is going to be used This is to be done while the robot is in the warm state see definition of robot states B The manual override between the auto pilot and the transmitter Ensure all flight control operations seamlessly transition from one to the other C Inspect the airframe for damage D Test the communications links between the multiple robots as well as the communication between the auto pilot and the high level board E Test the sensors and ensure accurate readings Be sure to zero any measurements In the event that something is disc
160. n Z FlightPian GPs PFD Mise Settings A ST Yelemastertext mayder o PF PEF 222722 TelamatterTest SCH Plan GPS PFD Misc Settings amp RC Sa SE SCH bi a 222738 ema eld Sy id ee ial ene meer al ETA NjA wg paromis sete Bes sato_theottle 2095 2229 33 TelemasterTest Starat N A io me params mode ie attitude m throttle auto pit 32 2933 relemanterTest Sandi Wm params mode ir attitude auto throttle auto pi 33 29 33 TelemarterTest Standt SS Kate SES o x 1 Mark pean o 2000 x4 t Mark poain o 2000 d t S m 50m Croll 06108 D v roil 06108 esn R Zeg Tie 90m troll 0 6108 0411 Py Late Ce Dash pose 19509 19509 000 D i hn D O Loter Cuise Dash zen 19500 _ 19500 000 r B LONG O Letter cruine Dash soen 9509 _ 19500 000 d J SS 0 000 V 9 DE 0 000 ocs j wwe as os Nav Maps Help TelemasterTest WGS84 2 355648 72 1247531 0 a wassa 42356249 72 125693 1 0 KS R R WJU KE 2 22 27 22 TelemasterTest Geo in 22 27 22 TelemasterTest AUTO Bloc re 5 22 27 22 TelemasterTest mayda Tas 4500 M Flight Plan GPS PFO Misc Settings amp RC Setting 57 31 TelemasterTest Holdin 22 27 22 TelemasterTest Geo in 22 27 22 TelemasterTest AUTO P Settings amp A Leeder maya Fight Plan GPS PFD Misc ings RC Setting eres 22 27 22 TelemasterTest Geo in 22 27 22 TelemasterTest AUTO 22 27 22 TelemasterTest mayda FROM Pian GPS PFD Mee Settings d
161. n and the environment in which they are located The first stage of any search and rescue mission is the awareness stage Before any rescue attempts are made there must be notification that there is a rescue to be made Once a distress call is received by a local search and rescue SAR organization the team next moves in to the initial assessment stage The initial assessment consists of determining what type of incident has occurred There are three different types of incidents which are uncertainty alert and distress each which require different tactics Following the initial assessment there is a comprehensive planning stage The goal of the planning stage is to derive the fastest and safest way to find the lost hiker and to coordinate the many different teams of rescuers once the plan is being executed The planning stage requires skilled rescuers typically with intimate knowledge of the area to be searched After the planning stage the operation begins This is when the rescuers risk their lives to search the area for the missing hiker Once the operation is completed the mission comes to the conclusion phase when the mission is considered successful or unsuccessful and all personnel return from the mission Joint Chiefs of Staff 1991 Speed is crucial with regards to the awareness and initial assessment stages as the chances for survival of an injured person decreases by as much as 80 in the first 24 hours The urgency of the response
162. n simulations based on predefined configurations for the autopilot control system Running simulations allows for initial testing of the system to determine how it responds before traveling to the testing field Two critical control loops of the control system is vertical and horizontal control The vertical control loop was simulated by launching the plane and having it fly to a target altitude Takeoff Pitch_Kd 500 Altitude Meters Pitch_Kp 20000 Pitch_Kp 10000 Pitch_Kp 5000 Target Altitude 0 20 40 60 80 100 120 140 160 180 Time s Figure 7 Simulation Results with different Kp values Waypoint Update Changed Roll Kp Meters 50 100 150 20 50 150 100 50 0 50 100 150 200 Meters Figure 8 Simulation Results with different Kp values By changing the proportional constant the control loop responsible for the position of the elevator the change in pitch of the plane during ascent is affected The horizontal control loop was simulated by setting a new target waypoint and examining the effect of the proportional constant on the roll set point of the plane The roll set point controls the position of the ailerons responsible for turning the plane 8 CONTROLS RESULTS On the senior Telemaster the team successfully completed two complete manual mode flights During one of the complete manual mode flights we successfully engaged Autol mode where the plane sustained a slight bank to the right F
163. n the tens of seconds The event of an emergency landing is the only time the safety hierarchy is to be altered In this event the flight controller controlling the robot in question assumes the position of chief flight controller and can direct the other robots out of the way to make for as safe of a landing as possible Indoor flight control surface testing Testing the different systems indoors is permitted however the robot is not allowed to pass beyond the warm state The engines will never be turned over under any circumstances indoors This allows testing on any of the electronics flight control surfaces and sensors in a controlled lab environment without endangering any of the project WIND personnel Storage of the Robot 106 The robots are just as dangerous when they are in storage mostly due to the fact that when the robot is being stored there are no project WiND personnel attending it These rules must be followed to ensure Safe storage of the robot A Keep the robot stored in a safe locked and secured location preferably by a key lock a swipe RFiD card reader or another comparable locking mechanism B Ensure the robot is stored without any batteries inside C Ensure any and all of the fuel has been drained D All access to the robot while in storage must go through the platform team or the overall team leader Adhering to these safety guidelines will ensure safe storage of the robot Reporting Incidents In or
164. nd type gt cd dev and then type gt Is This will display all of the devices currently available to the computer including internal You should be able to see ttyusbO as a device If not unplug then plug in the FTDI usb cable again 7 Now type 117 cd home lt username gt paparazzi Then gt make upload_bl PROC GENERIC This will upload the usb boot loader to the device on success the terminal should display Synchronizing OK Read bootcode version 2 12 0 Read part ID LPC2148 512 kiB ROM 40 kiB SRAM 67305253 SE SEN Download Finished taking 6 seconds Now launching the brand new code ioctl get failed ioctl set ok status 0 ioctl get ok status 2 ioctl get ok status 2 ioctl set ok status 2 ioctl set ok status 0 ioctl set ok status 0 Now you should be able to plug in the usb into mini usb connector on the paparazzi board power on the device and see in the dev ttyusb0 Autopilot Connection Now that the autopilot board has an usb bootloader the ground station software has the ability to download new code to it To upload new code 1 Connect the usb to the mini usb on the autopilot and make sure power is off 2 Plug in the usb to the computer 3 Turn on power to the autopilot 4 No lights should blink on the autopilot which signifies that the autopilot is ready to receive new code e Open up the paparazzi ground station Select your airframe and set you
165. nels and the time ranges for each Some systems currently use a PPM communication system and it s as simple as wiring the receiver s PPM line to the R C PPM IN pin on the autopilot board Unfortunately not all systems utilize PPM or the PPM trace is difficult to access on the receiver Our solution was the MeekpPE encoder board It is an open source PPM encoder board which takes the servo channels and mixes them into a PPM signal This allows for a PPM signal to be generated from any style of receiver system and without modification of the receiver See Appendix G User Manual Radio Controller Interface for more details on PPM and how it s measured MeekPe Encoder Top Figure 67 The top and the bottom of the MeekPe encoder board This encoder board allows us to read the commands for the servo channels from the radio receiver without modifying it Acquiring this board put the autopilot testing behind by a few weeks When the board was ordered it took the supplier over a month to arrive but this was due to some scheduled down time that the supplier In the mean time while waiting for the board the team attempted to make our own variant of it so progress could be made A few attempts were made to make our own and eventually had some success One of our attempts involved making our own printed circuit board by following an etching process This was attempted by downloading the gerber files and printing it on some photo paper using a laser jet
166. ng these waves in our video feed make the image processing algorithms more accurate since they have to do less filtering In some cases the sine waves are so distinct that even after filtering them out the image would be too disfigured to accuratly run the algorithms on dampening 41 Figure 50 Camera images with the engine on when the camera is simply taped to the bottom of the plane 42 3 UAV Control Design The second critical component to this UAV project is the control system The control system is in charge of driving the control surfaces of the plane based on external sensor measurements This section will cover the background research of existing control systems and external sensors commonly used in UAVs the approach to integrating a control system with a UAV system and the corresponding results 3 1 Background The two major components of a UAV control system is the autopilot system and the flight sensors used The autopilot system has control over all of the control surfaces of the UAV and senses the UAV s environment based on the flight sensors used 3 1 1 Autopilot In order to have the UAV s fly autonomously they will need an autopilot control system Designing an autopilot system from scratch is a complicated procedure and was highly suggested against by UAV communities and other university programs An autopilot system can be generalized in Figure 51 Ground Radio 24 Ghz Radio Controller Safet
167. nnection to the autopilot It was software teams responsibility to ensure that the communications team could provide the final data structure needed For updating waypoints the software team had to use the paparazzi protocol which consists of packed strings and floats with a checksum for error detection In addition to providing a command based system to update waypoints the platform team was responsible for housing all of the other team s electronics meet their power requirements and provide a camera gimbal system to house a camera for imaging The hardware platform team made integration accomplishments discussed below 6 1 External Waypoint Insertion With a complete autopilot system the goal was to integrate the autopilot control system with the Software team This entailed providing the ability to externally control the autopilot in an easy manner The goal was to have the plane follow the standby waypoint which is to be continuously updated by the software team s AI navigation path planning Currently the autopilot system can be updated externally by utilizing the ivy bus protocol which is currently used for communications between the autopilot board and the ground station Currently the autopilot board is connect to the IVY bus via a paparazzi source program titled link ml If this program is initiated it is simple as shown in Figure 98 to update waypoints using the existing Paparazzi protocol Unfortunately the paparazzi source l
168. ntegrated into the system GPS data was used to track the planes position and the IR thermopiles were in place for Auto 1 and 2 stabilization An attempt was made to implement a compass module for data collection GPS and thermopile readings are contained within the separate data files collected during testing 3 3 2 Data acquisition With the xBee radios streaming data back to the plane during RC flight tests the autopilot software system successfully recorded data during several RC piloted flights A sample of the telemetry data is displayed in Figure 92 na JA E fA 430 Cok 474 994 692 606 706 SLL SC AE KC EE s0930 s930 s990 295 s399 004 Topes e Be Geko s198 e216 mon es 394 S35 430 450 ATELTLEUDE O 097 51 9 EE Oi 3342 7 COMMANDS 80873m 4994A 2536 5079 46094 NAVIGATION 2 1 ied Pile Oe SOAs 3 Er H GPS 3 VSOALOIZ A693 7Z4517 624 L89200 14 s2 O74 4217 ood Et Le A FBW STATUS 0 49039 EE ALRSPEED B42 9502 Tao AS Ga PPM AS ZAG 2400 yp 2AA oy 66054 99909 20009 NAVIGATION 2 Dae sbe Ox S643 O y GPa a o GA FITA EE E oI CH S52 Er 217692000 Lo 2 NAVIGATION 2 1 KK gn en S63 E 0 CALIBRATION 0 0 RC 49 94 4094 72050 pH 194075062700 04 ATTITUDE Oel20024 1090482 0 120624 COMMANDS 80390 4895 2534 3074 4894 Eo CTIMATOR 16921938207 0 17 74306 NAVIGATION Zt Whol Sba Us 364 By 0 E Geo 2 P04 LOLs 26957248 G24 EE E S2 Lord 2h7652250 gt aver A WE MOVED 3
169. o controller it is possible to switch from Auto1 or Auto2 back into manual mode at any point This system will ensure the safety of the flight crew and the UAV itself during autopilot testing 3 2 3 5 Flight plan configuration file The flight plan configuration file contains the steps the UAV will take during the Auto2 mode First the way points are defined with a name and an x y coordinate The x y coordinate is in meters relative to the home location which is defined in latitude and longitude lt waypoint lt waypoint lt waypoint lt waypoint lt waypoint lt waypoint lt waypoint lt waypoint lt waypoint lt waypoint lt waypoint name HOME x 0 y 0 gt hame STDBY Mer ye LOO name 1 x 10 1 y 189 9 gt name 2 x 132 3 y 139 1 gt name MOB x 137 0 y 11 6 gt Name SiL et er ya 69 5 7 gt hame S2 KTZ TA sAm ye 2Z09 5T alt 30 20 mame AP Z 7 rA yaa SaL alta 0 20 fame TTD x 2Z6 28 y a0 7 gt name BASELEG x 168 8 y 13 8 gt neme CLIMB lt 11 4 5 ya 62 3 7 gt Figure 71 Waypoint Definitions within flight plan These waypoints are example waypoints contained within the flight plan The waypoints position is relative in meters from the home waypoint 61 ase Se ge S A Figure 72 Visualization of the flight plan over Tanner Hiller the local private airport the team tested the planes Next the sequential blocks are defined which contain t
170. o help avert accidents Once the manual was completed it was brought to the WPI safety coordinator and liability personnel for approval All members of the team and observers were required to sign this before the first flight 2 2 2 Goose Construction After doing extensive research on airplane design and construction the team first decided to try to design and build our own airplane from scratch to determine how feasible this was as an option First a CAD model of the design was created using the recommended ratios and NACA 2412 airfoil for the wings This plane was named Goose Goose had a 6 ft wing span Several different design phases were completed before settling on the final CAD model displayed in Figure 13 Figure 13 CAD of Goose s design before construction was started This CAD image doesn t include the MonokKote that will cover the wings and tail and fill in the gaps The body of Goose was made by carving blue insulation foam with a homemade hot wire Covering the body with fiberglass for extra support was tested however it was too heavy for the plane and ended up only being used around the wings attachment points The wings were made out of balsa wood that we cut on the laser cutter to our specifications An example of a template used in the laser cutter is shown in Figure 14 16 Figure 14 Laser Cutter template used to cut out the airfoil in the wings The boom to the tail is an aluminum tube which is screwed into the ta
171. obstacles like canyons fallen trees rocks rivers and cliffs Eventually over the course of a search they have to leave the relative safety of their vehicles in order to venture further into the wilderness by foot leaving them exposed to the elements anyways Joint Chiefs of Staff 1991 There is much room for improvement which is where Project WiND can help Project WiND was created to develop a network of unmanned aerial vehicles UAVs for use in search and rescue applications The idea is to send multiple inexpensive autonomous aerial vehicles out to fly low over the trees to aid rescuers find victims efficiently without risking the lives of rescuers The goal being to cover vast amounts of area quickly while streaming back data regarding potential victims back to a base station for verification by rescuers Once a victim is identified a search team can be dispatched to the exact location to extract the victim This will limit the time the rescuers are actually out in the field and therefore help keep them safe Also the efficient coordinated effort of multiple UAVs will greatly improve the amount of area which can be covered by a standard ground based search team Project WiND was divided into three separate projects the platform team the software team and the communications team The software team was responsible for the creation of the search algorithms to ensure that each UAV in the network was utilized effectively and effic
172. of flight plans Define a safe zone and a hot zone based off where the robots will take off and land Other than the ground controller NO Person under ANY circumstances is allowed into the hot zone without the consent of the flight controller This is to be done before the robot flies Hold a safety briefing with all personnel and spectators ensure that everyone understands the rules outlined by AMA as well as those outlined in this manual and sign any liability forms necessary Keep eye contact with the robot at all times while taxiing on the ground or in flight The flight controller is to be vigilant constantly assessing where the robot is and where the robot is going to be in the immediate future They need to be watchful of other planes trees buildings power lines and birds Even if the robot is under the control of the auto pilot the flight controller needs to be ready to override the auto pilot and switch to RC mode Announce a landing to all personnel and spectators with at least 2 minutes notice in the case of a scheduled landing and as soon as possible in the event of an unscheduled or emergency landing The announcement should declare Landing plus an estimated time of landing for example Two minutes to landing On the robot s final approach the Flight controller is to make one final announcement of Final approach to all personnel and verify with the ground controller that the runway is clear and safe for
173. om the ground as opposed to landing the UAV and uploading new changes between each flight Values defined in the settings file are shown in the settings tab within the ground station Flight Plan GPS PFD Settings DC Power switch flight params mode control ir attitude alt auto throttle auto pitch nav roll neutral 0 06283 pitch neutral 0 10472 360 lat_corr Figure 75 Settings Tab within Ground Station 3 2 4 Download and Operation Once all the configuration files were completed the autopilot software can be built and then downloaded to the YAPAZ2 This was an easy process using the paparazzi software See Appendix G User Manual Autopilot Connection for more details Before ground testing began simulations were ran on the configuration files to better understand how the system worked 3 2 5 Autopilot Simulations The paparazzi autopilot system provides the ability to run simulations on your airframe using the ground control station software First the user builds a simulated version of the airframe configuration files which defines the control characteristics of the plane what the flight plan will for the simulation what variables are changeable through the settings window and which telemetry messages are sent Running simulations on the airframe provided an initial feedback on how well the configuration files were configured and showed ideal r
174. om the battery 93 355 8 NAVIGATION 2 1 2 4 4 0 21 900 93 375 8 GPS 3 26853456 468411392 2955 160370 37 28 1662 252373750191 93 423 8 WP_MOVED 15 268414 5 4684145 5 234 559998 19 93 424 amp CALIBRATION 0 0 93 519 amp AIRSPEED 15 14 5 14 5 6 93 603 8 NAVIGATION 2 1 2 4 4 0 21 900 93 6318 GPS 3 26853456 468411392 2988 160290 34 32 1662 252374000 19 93 632 8 NAVIGATION 2 1 2 4 4 0 21 900 93 719 amp ATTITUDE 1 925012 5 238955 1 318443 93 823 amp ESTIMATOR 0 0 93 831 6 DESIRED 0 0 24 0 0 0 45 0 93 855 8 NAVIGATION 2 1 2 4 4 0 21 900 93 875 6 GPS 3 26653456 468411392 3001 160250 32 16 1662 252374250191 93 919 8 WP_MOVED 0 268579 4684152 234 559998 19 94 043 8 DOWNLINK_ STATUS 94 32917 1471 0 469 20 17 28 94 103 8 FBW_STATUS 2011260 94 111 amp NAVIGATION 21 3 4 0 25 00 94 1318 GPS 3 26853400 468411392 3153 160160 31 36 1662 252374500191 Figure 66 Above is a sample data file collected during tested The messages above were selected by the telemetry file and then recorded when received from the UAV 3 2 3 4 Radio Control Paparazzi autopilots provide a radio controller interface system for manual override of the UAV during flight This is a critical safety feature for the autopilot and also required by FAA regulations for civilian UAVs The autopilot expects a pulse position modulation PPM from a radio controller s receiver The radio configuration file defines each of the chan
175. one The size of the hot zone is specified by the amount of runway needed by the robot Each robot is a different size and will require different amounts of take off and landing space The hot zone must be physically marked using cones tape etc The area needs to be flat continuously open space The type of terrain the runway is depends on how the robot landing gear is configured For example if the landing gear is made for soft ground then a grass runway will suffice If there is snow on the ground there will have to be the potential to either clear a runway of snow OR apply snow skis to the robot to allow it to safely land on snow covered runways AMA Academy of Model Aeronautics fields will have this area marked already Hot Zone around the Robot While on the ground the robots will always remain in the hot zone Figure 0 1 is a picture of an airplane with the area immediately around the plane designated with colors A description of the colors is below 0 1 Immediate Robot Danger Zones NOT to scale Red The area in line with the propeller This is an immediate danger zone stay out Orange The area immediately around the robot The size of this area is to be calculated using the length of the wings The Value labeled R in the figure is the wingspan of the robot Only WIND personnel and their engine experts working on getting the robot flight ready are allowed inside the orange zone No other robots or foreign debris are allowed
176. oner the distressed victims are found Directly affecting the success of the mission is the sweep width of the SAR resources used The sweep width is how much area a search team or equipment can search per pass Sweep width is affected by the terrain the object being searched for and the type of resource For helicopters and slow fixed winged crafts the ideal search height is 500 ft allowing for a wide sweep path while not losing resolution of the search area For maritime search and rescue it is considered impractical to even attempt to spot a person in open water from greater than 500 ft For teams on foot sweep width is determined by the visibility of others on ground If a rescuer cannot see the rescuer to their right they are too far away This is heavily impacted by the environment in which the rescue is performed a dense forest will require smaller sweep widths than an open field 1 2 How can this be improved Unmanned Aerial Vehicles UAVs can be used to reduce costs while increasing the amount of area searched A UAV is an aircraft that is controlled autonomously or remotely from a ground station and therefore does not require a human to physically be on board to pilot the aircraft or work the various sensors and tools onboard This allows the aircraft which can be a fixed wing airplane helicopter quad rotor helicopter flying wing or any other airborne platform to be smaller and therefore more fuel efficient and cheaper to build
177. orks as a mask to the underlying search algorithm defined by the software team The concept is to allow the rescuers on the ground to alter the flight plans of the UAVs due to new information about potential locations of the victim This is also where the filtered images from the on board search and rescue cameras are displayed and analyzed by the rescuers Bringing all of these efforts together is the final portion of the project the platform development team whose work is represented by this paper The platform team was responsible for designing and building a fleet of UAVs capable of autonomous flight as well as carrying the large assortment of radios sensors and onboard computer processors The layout of the network is such that there are two different types of UAVs in the network the UAV designated the mothership and the rest are considered drones The mothership is the central communications hub both between all of the UAVs and the ground station The mothership carries the central path planning computer which runs the path planning algorithm developed by the software team The mothership uses the software defined radios developed by the communications teams at UNH and WPI to talk to the ground station and as such requires radios and all their supporting hardware including a small Micro ATX computer and appropriate amplifiers and antennae This allows the people on the ground to alter the search patterns of the UAVs while they are in flight
178. overed to be damaged or malfunctioning during the pre flight check it is up to the appropriate project WIND team to fix the issue before the robot will be permitted to fly For example if the team discovers damage to the landing gear the hardware team 105 will be responsible for fixing and repairing this before the robot can take off If the radio used to communicate with the other robots is malfunctioning the communications team will need to solve the issue before a flight can proceed Each robot involved in a test MUST complete EACH AND EVERY point listed above to be qualified to fly in the test 6 Starting the Engine These robots will be powered by a primary gas engine with a direct link to the propeller This is a very dangerous set up if not handled properly Project WiND is in contact with gas engine experts both from WPI and abroad to ensure the safe handling and starting of these engines These experts will be giving safety meetings to go over any and all precautions necessary for safely starting these engines All personnel from the hardware team will be required to attend these meetings however any other project WiND members or advisors can also attend Only WiND personnel with this training are allowed to be near the engine while it is fueled getting ready to be started or running While at test sites only the hardware team is allowed to attempt to start the engines with permission from the robot s respective flight controller
179. ow of the ground station is an ADC bias reading By adjusting the neutral values the ADC bias of the sensors can be removed Next the thermopiles were installed on the plane and the plane was brought out side to tune the roll and pitch neutrals The UAV could not have any man made obstacles within 500 1000ft First the neutrals were set to zero and placed the UAV on a level surface Then the ground control station was turned began collecting readings from the autopilot The neutral was set to offset the readings so that they are zero Any readings not zero when the UAV is level needs to have a correct offset Next the UAV was tilted to a measured angle The ground station reported the UAV s angle based on the IR readings If the angle is incorrect the values IR_360_Lateral_Correction and IR_360_Longitudinal_Correction were defined and adjusted independently to obtain the correct angle 54 The signs and corrections were used to change the sign of the reading of the thermopiles in case the sensor was mounted differently than intended Once the mounting system was solidified these values did not have to change The IR thermopiles were calibrated before each flight as they are the critical component for flight stabilization Control Surfaces Our next step was to configure the control surfaces so that the autopilot can control the heading of the plane The control surfaces fall under the commands section of the airframe configuration fil
180. p the direction of the servo swap the value for min and max Command Law Definition The paparazzi autopilot interfaces through the control surfaces using the command laws The command laws used by the autopilot are ROLL PITCH YAW and THROTTLE The command laws need to be set to the servos we previously defined Below is an example lt command_laws gt lt Connect the servos to the corresponding command laws of the autopilot gt lt set servo MOTOR value THROTTLE gt lt set servo AILEVON_LEFT value ROLL gt lt set servo AILEVON_RIGHT value ROLL gt lt set servo ELEV ATOR value PITCH gt lt set servo RUDDER value Y AW gt lt command_laws gt Here is where mixing can be done similar to options presented through the radio transmitter system lt command_laws gt lt let var aileron value ROLL AILEVON_ AILERON RATE gt lt let var elevator value PITCH AILEVON_ELEVATOR_RATE gt lt set servo MOTOR value THROTTLE gt 127 lt set servo AILEVON_LEFT value elevator aileron gt lt set servo AILEVON_RIGHT value elevator aileron gt lt command_laws gt This allows for mixing the elevator with the ailerons which allows for more stable turns RC Command Definition During AUTO the pilot has control over the ROLL and PITCH commands ailerons and elevator To add throttle and rudder add the following section lt auto_rc_commands gt lt Def
181. perating point thus reducing start up stresses and surges The internal 10 pA soft start current source gradually charges an external soft start capacitor con nected to the SS pin The SS pin is connected to the positive input of the internal error amplifier The error amplifier controls the pulse width modulator such that the FB pin approximately equals the SS pin as the SS capacitor is charged Once the SS pin voltage exceeds the internal 1 23V reference voltage the error amp is controlled by the reference instead of the SS pin The SS pin voltage is clamped by an internal amplifier at a level of 150 mV above the FB pin voltage This feature pro vides a soft start controlled recovery in the event a severe overload pulls the output voltage and FB pin well below nor mal regulation but doesn t persist for 256 clock cycles www national com 16 Various sequencing and tracking schemes can be imple mented using external circuits that limit or clamp the voltage level of the SS pin The SS pin acts as a non inverting input to the error amplifier anytime SS voltage is less than the 1 23V reference In the event a fault is detected over temperature VCC under voltage hiccup current limit the soft start ca pacitor will be discharged When the fault condition is no longer present a new soft start sequence will begin HO Ouput The LM5118 contains a high side high current gate driver and associated high voltage level shift This gate dr
182. puter Radio Pwr Radio Pwr Radio Pwr CAM Pwr FPGA Pwr Vbatt 1 R10 R12 10k 710k 10k R13 155R16 k 10k 10k 10k Figure 37 Controller Circuit Diagram BSSSRRE CEES CoV eM swEe B 31 The battery needed for this system will have to be able to produce a continuous 102 Watts for the system to fully operate This was calculated using the worst case conditions for example stall condition for servos then round up to the nearest tenth of an amp just as a precaution As for battery life it will need to last for at least an hour based on our expected flight time To meet the standards and to try to keep it as light as possible the team is recommending the use of a lithium polymer LiPo battery LiPo batteries are commonly used in the RC as the main power source for planes LiPo batteries have a high energy density and are moderately safe to handle and charge unlike lithium Ion batteries Barnard Microsystems Limited 2012 This system has yet to be fully developed due to time and budget constraints on the entire project but the design of this board is finalized and ready for the next steps in production 32 Testing The rest of the modifications made to the airframes were based on the results gathered during the test flights Figure 38 shows some still shots from one of Robin s takeoffs Both of these were stable takeoffs short and straight up without any power steering during acceleration or hard pulls onc
183. que and challenging experience The entire process can be broken down into four major steps These steps are understanding flight mechanics flying in an RC simulator flying using a buddy box system then flying solo 14 An airplane in flight has six degrees of freedom x axis y axis and z axis position roll pitch and yaw These variables are controlled on the plane by the control surfaces The elevator will affect the pitch of the plane which is used to help make the airplane climb The roll of the plane is controlled primarily in the ailerons of the airplane This will help the airplane bank and turn A combination of the ailerons and elevator will allow the airplane to make a successful banked turned Finally that yaw of the plane is controlled with the rudder and is primarily used only to get the airplane pointing ina specific direction when there may be a crosswind on a landing attempt Finally the last variable of an airplanes controls is the throttle Throttle does control the speed of the airplane but it is actually used to determine the altitude of the plane When you increase your speed on a plane you will be passing more wind over the wings thus causing more lift and gaining altitude Being able to properly control the throttle is a very important step in flying and it is most critical in takeoffs and landings It takes many hours of practice and numerous flights to be able to fully master all these variable for a successful flight
184. r If the peak of the emulated ramp signal exceeds 1 25V when operating in the buck mode the PWM cycle is immediately terminated cycle by cycle cur rent limiting In buck boost mode the current limit threshold is increased to 2 50V to allow higher peak inductor current To further protect the external switches during prolonged overload conditions an internal counter detects consecutive cycles of current limiting If the counter detects 256 consec utive current limited PWM cycles the LM5118 enters a low power dissipation hiccup mode In the hiccup mode the out put drivers are disabled the UVLO pin is momentarily pulled low and the soft start capacitor is discharged The regulator is restarted with a normal soft start sequence once the UVLO pin charges back to 1 23V The hiccup mode off time can be programmed by an external capacitor connected from UVLO pin to ground This hiccup cycle will repeat until the output overload condition is removed In applications with low output inductance and high input volt age the switch current may overshoot due to the propagation delay of the current limit comparator and control circuitry If an overshoot should occur the sample and hold circuit will detect the excess re circulating diode current If the sample and hold pedestal level exceeds the internal current limit threshold the buck switch will be disabled and will skip PWM cycles until the inductor current has decayed below the cur rent limit
185. r capacitors and the PGND pins of the LM5118 Connect all of the low current ground connections Css Ry Cramp directly to the regulator AGND pin Connect the AGND and PGND pins together through topside copper area cover ing the entire underside of the device Place several vias in this underside copper area to the ground plane of the input Capacitors www national com 22 The highest power dissipating components are the two power MOSFETs the re circulating diode and the output diode The easiest way to determine the power dissipated in the MOS FETs is to measure the total conversion losses Pin Pour then subtract the power losses in the Schottky diodes output inductor and any snubber resistors An approximation for the re circulating Schottky diode loss is The boost diode loss is P lour X Vewn If a snubber is used the power loss can be estimated with an oscilloscope by observation of the resistor voltage drop at both turn on and turn off transitions The LM5118 package has an exposed thermal pad to aid power dissipation Select ing diodes with exposed pads will aid the power dissipation of the diodes as well When selecting the MOSFETs pay careful attention to Rps on at high temperature Also selecting MOS FETs with low gate charge will result in lower switching loss es LM5118 onew yos uoneaddy jesidAL Ve AZL SL AHNDIS SS8S00E Oo 2 o D ONG ot ALIZ Bae ON9Y O Td NY r INT 49 BE An
186. r target to ap 7 Run Clean and then Make Make will take in all of the configuration files and compile the c code to download to the autopilot 8 Select Upload to upload to the autopilot If it does not work make sure the autopilot is powered To connect to the autopilot via USB to receive Telemetry 118 1 Within the airframe configuration file the following must be present within the firmware section lt subsystem name telemetry type transparent_usb gt lt subsystem gt 2 Build and Upload the new configuration file to the autopilot 3 Turn on the autopilot before plugging in the usb so that the autopilot does not go into the bootloader sector 4 Connect to the autopilot using Flight USB serial 9600 For this configuration the autopilot will show up as a ttyACMO device under dev Xbee Connection To connect to the autopilot via xbee radios the radios must be loaded with firmware first Acquiring X CTU X CTU is a windows software tool provided by Digi that allows you to update the firmware to the Xbee radios and then configure them as necessary X CTU can be obtained from the website http ftp 1 digi com support utilities 40002637_c exe and then executed with Wine on Linux Since X CTU is windows based it expects the Xbee device to be connect to a COM port To get around this in Linux you can make Wine see dev ttyUSBO as a COM device by using the following commands gt cd wine dosdevices gt In
187. rchased In order to implement the entire system each UAV would be mandated by the FAA to have a manual override utilizing a radio system like this Therefore in order to have three UAVs flying simultaneously there needs to be three completely separate radio systems present one for each airframe Since only one was purchased to save money knowing that even if two UAVs were flight ready a full system test with multiple UAVs flying simultaneously was nota short term possibility and therefore the same radio system could be used for multiple UAVs at different times There is a line item in the budget line 6 called 9 Channel remote for 89 This was purchased as a cheaper alternative to the DX6i early in the project but this ultimately failed Channel 1 was not transmitting properly and it was outside the warranty A replacement receiver module was ordered but did not fix the issue It was at this point that the DX6i was purchased Similar to the transmitter system there are things that never got purchased that will be necessary for future testing including a large capacity battery for powering the electronics for both 84 flight stabilization control and servos as well as the communications hardware image processing hardware and cameras Since this battery was never purchased it is not listed in the final budget The reasoning behind not purchasing the battery was its high cost as well as there was never a test scheduled that required
188. rdwood with receiving nuts embedded in it The piece of hardwood was secured to an aluminum frame which was custom made for the main compartment as shown in Figure 42 This frame reinforces the body and helps spread the load throughout the airframe This frame also supported the pan tilt camera gimbal that was designed This frame was in the original design but we didn t have a chance to add it until after the second test lt Support Rails ing Attachment Points a gt Figure 42 Aluminum support frame inside of Robin with the wooden mounting plate for the wings 36 The February 18t crash sheared the landing gear off of the fuselage and took most of the floor with it as well as the wing strut attachment points Pictures of the plane after the flight can be seen in Figures 43 Figure 43 What remains of the bottom of Robin s fuselage after its February 18th crash Notice how it is missing its landing gear and wing strut attachment points The Aluminum frame prevented further damage A picture of Robin after the repairs can be seen in Figure 44 All of the MonoKote on the front of the plane got ripped up during crash and therefore had to be replaced Thankfully the engine shaft was undamaged xf m vis Ee i Si L a al A E G e ioe N rey Me Ree 7 EC a AA Figure 44 Robin after its repairs from the February 18th crash 37 On April 11 Robin went out for its final test As part of our
189. re 14 Laser Cutter template we used to cut out the airfoil in the wmgs 17 Figure 15 Fully assembled Goose ready for Tloht 17 Figure 16 Unassembled Senior Telemaster Parts as they are shupped 18 Figure 17 Unassembled Skyline Champ Parts as they are sbupped 19 Figure 18 Stock RCG 20cc Gas Engine out Of the box 20 Figure 19 Internal layout with all of the components from all the teamS n nnennnennennnnnnennnnneennnnn 21 Figure 20 Internal layout with only the components necessary for Th 21 Figure 21 Robin with back hatches metalle 22 Figure 22 Robin with the servos moved to the back of the tail ee ccceeeeceeee ee eeeeeeeeeeaeeeeseeeeeaeees 22 Figure 23 Gas tank in its original position all the way forward sannnennannnennennnnnnnnnnnnnnnnnnnennnnnne 23 Figure 24 Sony color block camera that we will put in the planes ccceeccceeeeeeeeceeeseeeseeeeneees 23 Figure 25 Frequency responded for a silicon with a 6 on the Shore A hardness scale and optimal load OF 0 270 751 KOl e E 24 Figure 26 Frequency responded for a silicon with a 10 on the Shore A hardness scale and optimal OAC O10 3 72 KO COS WEE 24 Figure 27 Frequency responded for a silicon with a 14 on the Shore A hardness scale and optimal load Of 4 15 KQ 4 lege 25 Figure 28 CAD of Camera Gimbal with Sony Camera 25 Figure 29 Modifications to fit the gas tank chamber 26 Figure 30 The fuel tank chamber in place in the DOY
190. re considered for use with the autopilot 3 1 2 1 IR Thermopile IR Thermopiles measure infrared radiation IR in the same spectrum as the IR reflected from the Earth By arranging the thermopiles on the plane such that they face along the wings the planes orientation relative to the earth can be calculated When horizontal all thermopiles will measure approximately the same amount of IR with exception of the vertical thermopile As the plane turns and one wing faces the Earth the thermopile will measure a greater amount of IR compared to the other thermopile facing the sky The same principle can be applied for climbing and descending The vertical thermopile completes the six degrees of freedom to determine the planes approximate orientation in 3D space 46 Relative Responsivity 10 20 30 40 50 60 70 80 90 Angle of Incidence degree 90 80 7 0 60 50 40 30 20 10 0 Figure 55 IR Response Curve This curve represents the response of the thermopiles as the angle of the plane is changed http paparazzi enac fr wiki File Ir_response_curve gif mgt Vertical IR Figure 56 IR Thermopiles They are in charge of providing flight stabilization for autopilot mode Horizontal IR The thermopiles are arranged in pairs and wired through differential amplifiers to calculate the difference in IR readings The voltage output from the amplifiers are wired to analog inputs located on the autopilot board
191. re the safe usage of any products produced or used by project WIND under both test circumstances as well as real world applications Project WiND will be using unmanned aerial vehicles UAVs which are dangerous and therefore must be treated as such What makes these UAV s so dangerous are their size and their power The smallest UAV will have a 6 foot wing span while the largest may have upwards of a 12 foot wingspan They are also powered by either an electric motor or a gas engine either of which when attached to a propeller have enough torque to remove a finger from your hand These UAVs will be controlled by computers not humans which increase the risk of an accident during testing and operation However if the proper precautions are taken project WIND can ensure the safety for all involved These safety precautions are outlined here in this manual All members of the team must read this manual in its entirety and understand all of these protocols before any of the robots leave the ground Definitions Unmanned Aerial Vehicle An unmanned aerial vehicle abbreviated to UAV is an aircraft which is under the direct control of a computer for navigation and stability control The computer controls all movement of the aircraft and monitors all systems using sensors to ensure stable flight UAVs are capable of flying from GPS coordinate to GPS coordinate for navigation For the purposes of this document the term UAV and robot ar
192. reaches 75 the boost switch starts to operate with a very small duty cycle As VIN is further decreased the boost switch duty cycle increases until it is the same as the buck switch As VIN is further decreased below VOUT the buck and boost switch operate together with the same duty cycle and the regulator is in full buck boost mode This feature al lows the regulator to transition smoothly from buck to buck boost mode It should be noted that the regulator can be designed to operate with VIN less than 4 volts but VIN must be at least 5 volts during start up Figure 5 presents a timing illustration of the gradual transition from buck to buck boost mode when the input voltage ramps downward over a few switching cycles www national com SLLSIN LM5118 VOUT 12V 30058555 FIGURE 5 Buck HO and Boost LO Switch Duty Cycle vs Time Illustrating Gradual Mode Change with Decreasing Input Voltage High Voltage Start Up Regulator The LM5118 contains a dual mode high voltage linear regu lator that provides the VCC bias supply for the PWM controller and the MOSFET gate driver The VIN input pin can be con nected directly to input voltages as high as 75V For input voltages below 10V an internal low dropout switch connects VCC directly to VIN In this supply range VCC is approxi mately equal to VIN For VIN voltages greater than 10V the low dropout switch is disabled and the VCC regulator is en abled to maintain VCC at app
193. rframes the team decided on gas engines This was chosen because of the care and maintenance for the engines is not too difficult and the fuel is readily available The long term cost for the gas engine system compared to the nitro was less An electric motor for the class of airframe would require a very large heavy and expensive battery to meet the requirements The cost of the motor alone would be around 170 dollars plus 290 dollars for the batteries needed to power the motor for our targeted flight of an hour The power source for an electric system is more efficient because it would take up less space but fuel is more energy dense Golnik 2003 Barnard Microsystems Limited 2012 than the batteries and significantly cheaper 19 Figure 18 Stock RCG 20cc Gas Engine out of the box The RCG 20cc Gas Engine 2 2HP was chosen from HobbyKing com to power the Senior Telemaster based on recommendations from RC experts The RCG 30cc Gas Engine 3 9HP from HobbyKing com was chosen to power the Skyline Champ This engine fell within the recommended range of engines for the airframe by the manufactures An engine on the lower end of the range was chosen because the high performance a larger engine would provide was not needed Gas tank A larger gas tank allows a longer flight time However if the tank is too large for the airplane and not placed properly the pressure differential can drop the suction for the engine during aggressive maneuvers and
194. rong and how to prevent it from happening again It is also recommend that even after doing some flying with the buddy box system to go back into the RC simulator to try some maneuvers and practice landings 2 2 Platform Execution After gaining an understanding of the problem the team entered the execution phase of the project During this phase the planes were designed built and tested 2 2 1 Drafting a Safety Manual There were many concerns with having a project based around large scale model airplanes So before construction started a safety manual was drafted to address these concerns The safety manual accurately spelled out the different roles people would need to play during testing and how and where testing would occur These concerns included but were not limited to 15 1 Large engines with very large propellers spinning in excess of 8000 rpm 2 Loss of flight systems during a flight which could lead to a crash 3 Transportation of fuel to the testing site 4 Accidental damage to the airframes during storage and transport The manual needed to include procedures to avert accidents such as procedures for how to handle the loss of a flight system during flight The tools from organizations like the Academy of Model Aviation AMA and the FAA were used to help write the manual The help of small engine experts and large scale airplane modelers were used to ensure that our safety manual covered all of the necessary procedures t
195. roximately 7V A wide operating range of 4V to 75V with a startup requirement of at least 5 volts is achieved through the use of this dual mode regulator The output of the VCC regulator is current limited to 35 mA typical Upon power up the regulator sources current into the capacitor connected to the VCC pin When the voltage at the VCC pin exceeds the VCC under voltage threshold of 3 7V and the UVLO input pin voltage is greater than 1 23V the gate driver outputs are enabled and a soft start sequence begins The gate driver outputs remain enabled until VCC falls below 3 5V or the voltage at the UVLO pin falls below 1 13V In many applications the regulated output voltage or an aux iliary supply voltage can be applied to the VCCX pin to reduce the IC power dissipation For output voltages between 4V and 15V VOUT can be connected directly to VCCX When the voltage at the VCCX pin is greater than 3 85V the internal VCC regulator is disabled and an internal switch connects VCCX to VCC reducing the internal power dissipation In high voltage applications extra care should be taken to en sure the VIN pin voltage does not exceed the absolute max www national com imum voltage rating of 76V During line or load transients voltage ringing on the VIN line that exceeds the absolute maximum rating can damage the IC Both careful PC board layout and the use of quality bypass capacitors located close to the VIN and GND pins are essential V
196. s Heggie et al 2009 Of these 3 39 ended up in fatalities and 30 94 in personal injuries to the victim 3 39 is a small fraction but this number would be closer to a 20 fatality rate without the presence and quick response of search and rescue teams Heggie et al 2009 This clearly shows from the victim s perspective the need for fast and accurate search and rescue efforts in our national parks and beyond The challenges and risk to the rescuers are great as well Musculoskeletal injuries were the most common type of injury that SARA Southern Arizona Rescue Association members suffered over 30 years These included two fractures a disrupted knee a shoulder dislocation and sprains requiring emergency department evaluation There were many more minor sprains and strains for which no assistance was needed Iserson et al 1989 Current search and rescue techniques include a lot of heavy machinery including but not limited to cars trucks all terrain vehicles helicopters and planes The rough terrain compounds the need for skilled operators pilots and drivers Pilots need to take planes and helicopters close to the treetops in order to be able to spot the survivor through the trees combined that with the ever changing slope of a mountain range and it becomes a recipe for disaster The task of searching is no easier for the ground crews navigating cars and trucks on dirt paths and windy mountain roads avoiding
197. s rotational speed and the pitch of the propeller Vertical Performance and Airspeed Step three is to determine the Vertical Performance and Airspeed The rate of climb is a factor of the power plant propeller being used and the ready to fly weight The propulsion source propeller and wing design determine the airspeed Both of these will affect the size and payload of the final airplane design The rate of climb may be compromised in the final design to achieve the desired speed Wings The next step is to design the wings There are several different components to designing the wings The chart indicates which aspects of flight each wing factor effects Table 1 this table Identifies which flight characteristics are effected by different Design Parameters Design Parameters Flight Characteristic E Wing Loading Aspect Ratio Dihedral et ii Paap Lift Capability Lift Drag Ratio Aerobatics The Airfoil The wing geometry affects the wing lift and center of inertia distributions in a mostly intuitive way Stanford University 2001 They Ess come in several different styles Johnson 2007 symmetrical semi Figure 9 Airfoil Geometry Symmetrical symmetrical flat bottom modified flat bottom under cambered and reflexed Each one of these styles contains a large number of airfoils that have similar shapes Also data on real airfoils dont directly apply to their Figure 8 Airfoil Geometry scaled down counter parts
198. sell Naughton June 22 2003 The Aerial Target and Aerial Torpedo in the USA first Online Available http www ctie monash edu hargrave rpav_usa html Airplane research Bill Smith 2006 Blue Foam Wing Construction first Online Available http www clapa org BLUE 20FOAM 20CONSTRUCTION 20FOR 20CONT ROL 20LINE pdf Ron Alexander October 1997 Building Composite Aircraft first Online Available http www sportair com articles Building 20A 20Composite 20Aircraft html 94 Mike Harris 2005 Weight Analysis of Composite Airframe Construction first Online Available http www privatedata com byb rocketry composites composite_airframes html Ron Alexander May 1999 Basics of Composite Construction first Online Available http exp aircraft com library alexande composit html Honus June 3 1997 Simple Methods for Molding Fiberglass and CarbonFiber first Online Available http www instructables com id Simple methods for molding fiberglass and carbon f Hobby Lobby January 2012 AXI Gold 4120 18 Out Runner Motor first Online Available http www hobby lobby com axi_gold_4120 18 outrunner_motor_3039_prd1 htm Hobby Lobby January 2012 4500mAh 4S 14 8V 20C LiPo Battery w Deans first Online Available http www hobby lobby com 4 cell 14 8v_ 4500mah 20c lipo pack 364091 prdi htm Arthur Golnik 2003 Energy Density of Gasoline first Online Available http hypertextbook com facts 2003 Art
199. sional and amateur UAV developers These solutions include Piccolo ArduPilot and Paparazzi 3 1 1 1 Piccolo Piccolo is an autopilot system developed by students from MIT The piccolo autopilot is an all in one system for flying a UAV and uses proprietary software designed by MIT students and graduates The package includes the autopilot software flight sensors navigation sensors and wireless communication This product is considered successful in the field of UAVs although it costs 4 000 after academic discounts This autopilot system is a black box system where the components are difficult to exchange with new components Many UAV research projects utilize the Piccolo autopilot Almeida et al 2007 Garcia et al 2007 Almeida et al 2006 Figure 52 Piccolo autopilot system Piccolo is an all in one solution for autonomous flight provided by MIT http www cloudcaptech com piccolo_II shtm 44 3 1 1 2 ArduPilot ArduPilot is an open source autopilot project similar to Paparazzi that runs on modified arduino megas Arduino megas are readily available development microprocessor boards It is known for its simplicity and easy to use ground station software The ground station software expects sensors only from the supplier of ArduPilot diydrones com so it takes more development time for implementing new sensors that are not offered Many UAV research projects utilize ArduPilot Bin et al 2009 Kabbabe et al 2011 Joseph et al 201
200. sk areas as early as World War I Naughton 2003 Since then technology has been advancing New sensors have been developed and implemented both for flying the UAV as well as for reconnaissance The most common sensor on a UAV is some variant of a camera a rather simple but very valuable sensor There is currently a wide verity of sensors that are being used on UAVs such as atmospheric sensors geomagnetic sensors internal measurement units IMUs and synthetic aperture radar just to name a few With this great variety of sensors the exact use of UAVs is almost unlimited Some common uses of UAVs include Remote Sensing Reuder Joachim et al 2009 Commercial Aerial Surveillance Jensen A M et al 2008 Scientific Research Reuder Joachim et al 2009 Armed Attacks Bolkcom 2004 Schmitt 2012 Civil Defence Border Patrol Bolkcom 2004 Search and Rescue Michael A Goodrich et al 2008 Figure 3 is an image of an MQ 9 Reaper UAV currently deployed by the United States Air Force and is used as a hunter killer drone armed with AGM 114 hellfire missiles Its current primary mission is for use in counterterrorism missions U S Air Force 2012 The use of UAVs in search and rescue is not common yet but with the increasing advances in technology and decreasing costs it may not be too far off in the future that systems like the one developed by this project Figure 3 The U S military s MQ 9 Reaper drone used for counter t
201. slowly They can also support quite a bit of weight While a very stable platform this type of plane is Figure 7 Sailplane a type of scaled plane with long difficult to maneuver thin wings used for gliding Designing an Airplane A well designed airplane requires a lot of time and thought According to Paul Johnson a model aircraft designer there are several clear steps to designing a small aircraft Johnson 2007 Specifications Johnson first recommends determining the specifications for the vehicle These specifications may include any of the following and are discussed in detail in the following sections e Purpose of the model e Type o Trainer Scale War bird park Fliers etc Flight time Based Size and Propulsion choice Stability o Should the model be self stabilizing neutrally stable or somewhere in between Airspeed envelope Vertical performance Control response Stall characteristics Construction methods o Traditional wood composite etc Control system Landing gear system Break down for transportation Propulsion The next step is to choose a propulsion source Selection of a propulsion source is important because if an airplane is designed to support a range of different power plants it must be structurally designed to support the largest one This might not be the best aerodynamically or end up too heavy for the smaller power plants to lift The speed of the airplane is equal to the product of the propeller
202. ssemble and fly Warbirds are planes that are modeled after military Figure 5 Warbird a type of scaled aircrafts These planes are smooth flying and aesthetically plane modeled after military aircrafts pleasing Weis 2007 Some of them are also modified to http www raidentech com new20f4u improve their flight characteristics co4e html Sports Models are typically narrow wing airplanes intended for aerobatic and for advanced fliers Most of these planes have the wings mounted near the bottom of the body They exchange stability for maneuverability FlatOuts planes are typically made from re enforced foam They are quick and easy to assemble and easy to fly However they have short flight times because they are unable to Figure 6 Sports Model a type of scaled plane intended for aerobatic flight http product madeinchina com RC g Airplane Model Sport Fun 46P_13077777 shtml support large power plants Usually used to practice aerobatic maneuvers or for spontaneous flights Park fliers are small electric powered airplanes that can be flown just about everywhere Towers 1996 They are cheap and durable since they are made from plastic instead of balsa wood They also can be flown safely anywhere They are also exclusively for beginners Sailplanes have long thin wings and are used to glide and rise using the atmospheric thermal streams Because of how easier they are to glide they are used to travel long distances
203. st be considered www national com SLLSIN LM5118 to guarantee a given output ripple voltage Buck boost mode Capacitance can be estimated from Vout lout X Dmax With D MAK Vinz Vout E f x AVout ESR requirements can be estimated from AVout ESRmax PEAK For our example with a AVOUT output ripple of 50 mV If hold up times are a consideration the values of input output capacitors must be increased appropriately Note that it is usually advantageous to use multiple capacitors in parallel to achieve the ESR value required Also it is good practice to put a 1 UF 47 uF ceramic capacitor directly on the output pins of the supply to reduce high frequency noise Ceramic capacitors have good ESR characteristics and are a good choice for input and output capacitors It should be noted that the effective capacitance of ceramic capacitors decreases with dc bias For larger bulk values of capacitance alow ESR electrolytic is usually used However electrolytic capacitors have poor tolerance especially over temperature and the selected value should be selected larger than the calculated value to allow for temperature variation Allowing for compo nent tolerances the following values of Cout were chosen for this design example Two 180 uF Oscon electrolytic capacitors for bulk capaci tance Two 47 uF ceramic capacitors to reduce ESR Two 0 47 uF ceramic capacitors to reduce spikes at the out put
204. stop fuel flow thus stalling the engine Because of these factors a 32 oz tank was chosen for the Telemaster which gave the airframe a nice balance of both size and functionality A 40 oz tank was chosen for the Skyline champs to the airframe comparable flight time with the Telemaster Propeller Propellers have two important dimensions that affect their performance the diameter and pitch The pitch affects the top speed of the airplane It is defined as the distance the propeller would move in one revolution if it were moving through a soft material like a screw through wood A lower pitch will force the engine to reach max rpm at a lower speed A larger pitch has a higher top speed but slower acceleration The diameter of the propeller is determined by the desired rpm and power of the engine Since a slow moving airplane with a lot of power was desired a large propeller with a small pitch was selected On the Telemaster a 16 inch diameter with a 4 inch pitch 16 4 was ideal On the Skyline Champs a 18 inch diameter propeller with a 6 inch pitch 18 6 was ideal 2 2 4 Robin Air Frame Modification Before it was flight ready a few modifications were made The first modification was adding 2 degrees of trust to the right to the preexisting engine mount To balance all of the internal components inside the fuselage a CAD model of the Telemaster fuselage was created and recreated all of the 20 components in CAD as well Two different layouts for
205. switching regulator features all of the functions necessary to implement an efficient high voltage buck or buck boost regulator using a minimum of external components The regulator switches smoothly from buck to buck boost operation as the input voltage approaches the output voltage allowing operation with the input greater than or less than the output voltage This easy to use regulator integrates high side and low side MOSFET drivers capable of supplying peak currents of 2 Amps The regulator control method is based on current mode control utilizing an emulat ed current ramp Peak current mode control provides inherent line feed forward cycle by cycle current limiting and ease of loop compensation The use of an emulated control ramp re duces noise sensitivity of the pulse width modulation circuit allowing reliable processing of very small duty cycles neces sary in high input voltage applications The operating fre quency is user programmable from 50 kHz to 500 kHz An oscillator synchronization pin allows multiple LM5118 regula tors to self synchronize or be synchronized to an external clock Fault protection features include current limiting ther mal shutdown and remote shutdown capability An under voltage lockout input allows regulator shutdown when the input voltage is below a user selected threshold and a low VIN HB Q1 HO a HS D1 per an LM5118 E CN cs CSG LO state at the enable pin will put the regulator into an ex
206. t Holdin amp oe E H 21 32 TelemasterTest Takeof amp be gu 22 27 22 TelemasterTest Geo in A 2227 22 TelemasterTest AUTOL E 22 27 22 TelemasterTest mayda ght Plan GPS PFD Misc Settings S RC Setting 27 31 TelemasterTest Holdin 22 27 22 TelemasterTest Geo in amp 22 27 22 TelemasterTest AUTOLE Block fo d 22 27 22 TelemasterTest maya Time pap EH FIARPlan CPS Misc Settings A e e sening 2 272 TelemasterTest Holdin 4 Block r Time org Z O Stoge0716 oe 22 27 32 Telemastertest Takeof amp N A params mode ir attitude auto throttle suto pit 29 33 TelemasterTest Standt d ETA M A Wu params mode ir attitude suto throttle auto pib 222933 TelemasterTest Standt Stogeoasos SS panara pre onea PA 22 ar z Felemaster Test Dei Mark pgain o 9000 d 4 Mark poain o 7000 H M W 0000 6 0 611 5 0611 pgar 0 gu 4 Som qroll 0 6108 4 P Crom 0 6108 6 r H argat Ap esi Cruise Dash 19500 9000 6 O Loiter Cruse Dash 19500 9000 6 zim S3m 50m LF 06108 d E f gen 19500 sg 6 _poain 19500 P 6 NIO Leiter Cruise Dash a t9500 19500 000 4 6 Pan VM DU K 0 000 Ansa 0 000 6 as eeng ccs t S 42355648 7212475310 j Nav Maps Help TelernasterTest gt wass 3 42355995 7212577310 1 a wass 5142355648 72 1247530 22 27 22 TelemasterTest Geo in 4 2227 22 TelemasterTest AUTO 22 27 22 TelemasterTest Geo int 22 27 22 TelemasterTest Geo i
207. t of priority items can be found in Table 2 28 The purpose of having this priority list is to determine what items can be turned off without losing functionality of the flight of the plane for as long as possible in low power situations For the independent systems it was determined that it would be best if each had its own controllable regulator The design used an LM5118 which is a wide voltage range buck boost controller This particular controller can take an input from 3 Volts to 75 volts and output it from 5 to 15 volts As for the current this devise is only a controller for the switching of the MOSFETs for the buck boost converter so we just specified ones that can handle up to 10A Table 2 Power board specifications System Voltage Current Allowed Priority level Power c S S E RE priority goes from highest being 1 down to 4 the lowest Each regulator circuit is using the same fundamental design with the only difference being different values in a few of the resistors or capacitors in the supporting circuitry For instance the ratio of the resistors R8 and R9 will determine the output voltage by this equation z EES 1 The calculation and description for maximum output current is a little more involved and is best described in the data sheet for the LM5118 which can be found in the Appendix I With the setup the regulators are going to be useed around their most efficient point For this regulator the efficiency is
208. t of these simulations the baseline values for these variables will be set to a pitch kp of 10000 and a pitch kd of 500 Horizontal Control Loop The horizontal control loop oversees waypoint navigation The overall horizontal control loop can be broken down into the navigation loop the course loop and the roll loop Figure 85 shows a flow chart depicting the structure of the horizontal control loop 70 Horizontal Control Navigation Loop Course Loop Rall Loop Flight Plan Pitch Loop Throttle Loop Altitude Loop Climb Loop Figure 85 Horizontal Control Loop The different navigation routines from the flight plan dictate the target waypoint for the plane The course control loop s input is the course_setpoint which is determined from the current navigation routine h_ctl_course_setpoint rall_ setpoint max_roll_set_point max roll set point course pre_bank_correction Estimator Heading Figure 86 Course Control Loop The course control loop shown in figure 86 generates a roll setpoint based on the current heading and the target heading A course_pre_bank_correction can be added to compensate for consistent errors in turning such as inconsistency in the servos or imperfections in the wings Roll_setpoint is limited by a max roll set point This prevents the plane from performing barrel rolls during flight The roll_setpoint is the input to the roll control loop which is in charge of setting
209. t was kept at 0 and then the kp constant was varied as represented in the QA DIN RCV s icascecetetetecptsaateaoiet satan tcaieretsaecdeiaa A 69 Figure 83 Pitch Launch Simulation Kd 500 The graph above shows three simulations where the kd constant was kept at 500 and then the kp constant was varie 69 xi Figure 84 Pitch Launch Simulation Kd 500 The graph above shows three simulations where the kd constant was kept at 500 and then the kp constant was va re 70 Figure SO HOFIZONtAall Gonto LOOP EE 71 Foure 86 Course Control LOOP E 71 Figure O72 ROll COMO LOO EE 72 Figure 88 Waypoint Navigation Simulation ccccccceeccseeeceeeeceeeaeeeseueeseeeeeeeseueeseeeseueeseeesaneessees 72 Figure 89 Waypoint Navigation Simulation The goal of this simulation was to examine the effect of changing the roll attitude_gain on waypoint navigation When the plane was stable circling the standby waypoint the target waypoint was moved down the runway cceccceeeeeeeseeeseeeseeeneeenes 73 Figure 90 Flight Gear Simulation This multi image figure depicts the takeoff simulation of paparazzi alongside flight gear Flight gear is an open source radio control flight simulator The time of each picture was taken from the video is labeled cccccceeccecceeeceeceeeeeeeeeeceeeeeeseeeaeeeees 74 Figure 91 Multi plane Simulation This multi image figure demonstrates a simulation in which two separate planes are flown One plane is in bl
210. tage and one from a separate bias supply In the first case the internal VCC regulator is used to initially bias the VCC pin After the output voltage is established the VCC pin bias current is supplied through the VCCX pin which effectively disables the internal VCC regulator Any voltage greater than 4 0V can supply VCC bias through the VCCX pin However the voltage ap plied to the VCCX pin should never exceed 15V The voltage supplied through VCCX must be large enough to drive the switching MOSFETs into full saturation 30058551 FIGURE 16 VCC Bias from VOUT 4V lt VOUT lt 15V 21 www national com SLLSIN LM5118 HB VIN Q1 LM5118 VOUT on ia vcc VOCH T D2 VOUT VBIAS 30058552 FIGURE 17 VCC Bias with Additional Bias Supply PCB Layout and Thermal Considerations In a buck boost regulator there are two loops where currents are switched very fast The first loop starts from the input ca pacitors and then to the buck switch the inductor the boost switch then back to the input capacitor The second loop starts from the inductor and then to the output diode the output capacitor the re circulating diode and back to the inductor Minimizing the PC board area of these two loops reduces the stray inductance and minimizes noise and the possibility of erratic operation A ground plane in the PC board is recom mended as a means to connect the input filter capacitors to the output filte
211. tching frequency Generally speak ing higher operating frequency applications will use smaller components but have higher switching losses An operating frequency of 300 kHz was selected for this example as a rea sonable compromise for both component size and efficiency The value of R can be calculated as follows _ 6 4 x 109 3 r 3 02 x 10 R therefore R7 18 3 KQ lo Buck Iripple lo 1 D B B L1 Current D i i i D i i i a Ka lripple 30058529 FIGURE 12 Inductor Current Waveform INDUCTOR SELECTION L1 The inductor value is determined based upon the operating frequency load current ripple current and the input and out put voltages Refer to Figure 12 for details To keep the circuit in continuous conduction mode CCM the maximum ripple current IRIPPLE should be less than twice the minimum load current For the specified minimum load of 0 6A the maximum ripple current is 1 2A p p Also the mini mum value of L must be calculated both for a buck and buck boost configurations The final value of inductance will generally be a compromise between the two modes It is de sirable to have a larger value inductor for buck mode but the saturation current rating for the inductor must be large for buck boost mode resulting in a physically large inductor Ad ditionally large value inductors present buck boost mode loop compensation challenges which will be discussed in er ror ampl
212. that much power In fact there was only one flight that incorporated additional electrical components over the standard flight electronics and the extra board did not draw enough power to warrant purchasing the larger battery at that time We also only have two complete autopilot systems which includes the autopilot board the GPS sensor the IR thermopiles and the encoder board We only have two complete sets because in January it was decided to focus on getting two of the UAVs airborne properly rather than spread the existing funds too thin and not being able to successfully construct all three airframes This also explains why there are only two gas tanks and only enough fuel line for two airframes An additional gas tank and more fuel line will be required to finish the last UAV Duck For a complete list of what is left to purchase and complete on Duck see section 2 2 6 6 Integration with Software and Communications Project wind is broken down into 5 distinct teams three of which were located at WPI and the other two were at UNH The hardware platform team who is the topic of this report features integration primarily with the software integration team For Project Wind our teams goal was to provide a platform which can navigate waypoints that can be continuously updated using an easy to use command system Software team would then generate the target waypoints to update the autopilot For the software team we had to provide an USB for co
213. the Senior Telemaster The Senior Telemaster has a 7 83 ft wingspan and 9 24 square feet of lifting area It is a trainer plane and is notoriously easy to fly for beginner pilots It also has a 10 pound payload capacity which fits our expected payload Several other college teams are working on UAV projects using this airframe University of Alberta 2011 This plane was named Robin Figure 16 Unassembled Senior Telemaster Parts as they are shipped For the mothership a larger payload was needed because the mother ship needs to fit the large USRP2 radio and its supporting hardware for the base station downlink A similar airframe to the Telemaster was desired so that it would as easy to fly and so that many of the configurations from the Telemaster could transfer over to the new airframes The team selected the 8 8 ft wing span airframe the Skyline Champ with 11 5 square feet of lifting area Two of these frames were purchased the blue one was named Jay and the yellow one was named Duck Like the Telemaster this airframe is also a trainer style and easy to fly 18 Cow Figure 17 Unassembled Skyline Champ Parts as they are shipped In general larger airplanes are easier to fly then smaller ones because they are more stable in the air due to a higher moment of inertia This is to our advantage when flying under autopilot and doing video surveillance Propulsion After considering all of the engines and motors available for our two ai
214. the interior were created one with all of the components and one with only the components necessary for autopilot fight Center of Gravity Intel Atom Figure 19 Internal layout with all of the components from all the teams Battery Ignition Battery Ignition Figure 20 Internal layout with only the components necessary for flight While examining our CAD drawing it was determined that the rear compartments in the fuselage were needed for space Hatches were installed utilizing pieces of wood and a hinge which allowed access to components in the rear of the plane with ease as seen in Figure 21 21 Added Access Hatch Figure 21 Robin with back hatches installed The next major change made was the location of all the internal servos The plane was designed to have all of the servos in the middle of the plane under the wing however that area needed to be cleared Also the way the servos originally controlled the rear control surface was unreliable It was using long pushrods that could flex slightly undesirably allowing the elevator to shift out of position under load The problem was solved by shortening the push rods and moving the servos to the back of the plane utilizing the new hatches as seen in Figure 22 a Se ke in 7 es gt oo PN s 5 H SP P i WC Servos Moved to the Back Figure 22 Robin with the servos moved to the back of the tail The next major modific
215. the other airframe and then runs the simulation This will generate a single ground control station for both airframes where each can be controlled separately wv as www os ve Naw Maps Help TelmmasterTest Jap SifineChanp Nav Maps Help TelemasterTest Jay SkyfineChanp 11 32 07 Jay SkylineChamp H Time 1 29 U nm j Flight Plan GPS PFO Misc Settings 3 RC Setting11 H t 1 Ti d Flight Plan GPS PFD Misc Settings Ri 211 Y blocks 4d e blocks gt block Wait GPS gt lock ini Figure 91 Multi plane Simulation This multi image figure demonstrates a simulation in which two separate planes are flown One plane is in blue and the other is in red The time in which the snapshot was taken is located on the bottom right of each picture Running a simulation of two airframes allows for the visualization of a test plan featuring multiple airframes For this simulation each airframe was compiled with the same flight plan 3 2 5 Autopilot Testing After running simulations of the system the team moved to physical testing of the autopilot system Testing the autopilot started with testing on the ground within the lab and then was moved 19 outside to examine the response of the IR thermopiles and the consistency of the GPS Our plan for autopilot testing is explained in the following subsections Autopilot Ground Test Once the airframe was confirmed operational via radio control test flights we then installed the
216. threshold This approach prevents current runaway conditions due to propagation delays or inductor saturation since the inductor current is forced to decay before the buck switch is turned on again CURRENT SENSE AMPLIFIER RG 30058523 FIGURE 10 Current Limit and Ramp Circuit www national com 8LLGNT LM5118 Maximum Duty Cycle Each conduction cycle of the buck switch is followed by a forced minimum off time of 400ns to allow sufficient time for the re circulating diode current to be sampled This forced off time limits the maximum duty cycle of the controller The actual maximum duty cycle will vary with the operating fre quency as follows where f is the oscillator frequency in Hz MAX DUTY CYCLE FREQUENCY kHz 30058526 FIGURE 11 Maximum Duty Cycle vs Frequency Limiting the maximum duty cycle will limit the maximum boost ratio VOUT VIN while operating in buck boost mode For example from Figure 11 at an operating frequency of 500 kHz Dmax is 80 Using the buck boost transfer function E Vout Vin Vout With D 80 solving for VOUT results in VOUT 4 x VIN With a minimum input voltage of 5 volts the maximum pos sible output voltage is 20 volts at f 500 kHz The buck boost step up ratio can be increased by reducing the operating fre quency which increases the maximum duty cycle Soft Start The soft start feature allows the regulator to gradually reach the initial steady state o
217. topilot configuration file to define the ranges of the servos Repeat 3 6 for all of the servo channels 124 8 Connect the receiver channels to the MeekPE board The order and amount of channels does not matter except the last servo channel from the last step must be plugged into the last servo of the MeekPE 9 Hook up an oscilloscope probe to the output PPM of the MeekPE and make sure the MeekPE board is powered either from the receiver or through the 5v line on the MeekPE board Tek Ape Trig d M Pos 4 600rms CURSOR Type SOUTCE at 22 00ms aq d s ay DODY Cursor 1 9 80m 0 0g Cursor 2 2200s 14 b Uu CH1 2 004 CH2 2 00 Wi S 00rns CH1 1 60 Reta 1 00 DUU Us 45 4194Hz Figure 103 PPM Signal 10 By moving the sticks on the radio controller you should see the packet change widths on the oscilloscope Find the channel that is first on the left and notate which control surface it affects aile elev etc 11 Measure the width of the channel when the stick is in the neutral position Tek PL Trig d M Pos 14 72ms CURSOR Type SOUTCE at 1 660ms a z 602 4H2 e Zb 4V Cursor 1 14 0ms 0 0g Cursor 2 Sims G A SEA CH1 AU CH2 2 00 M 250 05 CH1 1 604 Herno 1 00 DUU Us 45 4224H2 Figure 104 Neutral Channel One 12 Measure the width of the channel when the stick is in one extreme and then the other extreme 125 13 Take note of these values as they will have to
218. tremely low current shutdown state The device is available in the TSSOP 20EP package featuring an exposed pad to aid in thermal dissipation A buck boost regulator can maintain regulation for input volt ages either higher or lower than the output voltage The challenge is that buck boost power converters are not as ef ficient as buck regulators The LM5118 has been designed as a dual mode controller whereby the power converter acts as a buck regulator while the input voltage is above the output As the input voltage approaches the output voltage a gradual transition to the buck boost mode occurs The dual mode ap proach maintains regulation over a wide range of input volt ages while maintaining the optimal conversion efficiency in the normal buck mode The gradual transition between modes eliminates disturbances at the output during transi tions Figure 2 shows the basic operation of the LM5118 regulator in the buck mode In buck mode transistor Q1 is active and Q2 is disabled The inductor current ramps in pro portion to the Vin Vout voltage difference when Q1 is active and ramps down through the re circulating diode D1 when Q1 is off The first order buck mode transfer function is VOUT VIN D where D is the duty cycle of the buck switch Q1 Buck Switch Current Q2 OFF 1 30058511 FIGURE 2 Buck Mode Operation Figure 3 shows the basic operation of buck boost mode In buck boost mode both Q1 and Q2 are active for the
219. ts and drivers Pilots need to take planes and helicopters close to the treetops in order to be able to spot the survivor through the trees combined that with the ever changing slope of a mountain range and it becomes a recipe for disaster The task of searching is no easier for the ground crews navigating cars and trucks on dirt paths and windy mountain roads avoiding obstacles like canyons fallen trees rocks rivers r and cliffs as well as performing high risk Figure 2 This is an image of rescuers a l g g maneuvers such as rock climbing as depicted in performing near vertical rock climbing to locate and attend to a victim a very risky maneuver El Paso Country Search and Rescue also takes a lot of time and requires a lot of training Figure 2 This not only puts the rescuers at risk it 1 1 How is Search and Rescue done now Overall whether on the ground or in the air search and rescue is a dangerous occupation It is also highly inefficient because it relies on the trained eye of a human who may or may not have a clear view of the area around the victim Speed efficiency safety and even cost are all areas to be addressed in search and rescue operations According to the International Aeronautical and Maritime Search and Rescue Manual IAMSAR Joint Chiefs of Staff 7991 all search and rescue missions are executed in five precise stages each of which highly depend on the people in distress their conditio
220. ue and the other is in red The time in which the Snapshot was taken is located on the bottom right of each picture ccc ec cc eeeceeeceeeceeeeeeeseeenes 75 Figure 92 Data Acquisition during Manual Autopilot control This portion of data shows RC messages with complete RC commands from the remote controller and updated GPS positions 78 Figure 93 Autopilot data acquisition during RC flight This figure alternates between the ground control station displaying the UAV s position and the UAV flying cccceccecceeeceeeeeeeeeeeeeeeeeaeeees 79 Figure 94 Successful takeoff using the manual mode of the autopilot nennnensnenneeneneneesneennenn 80 Figure 95 Multi plane connection This image demonstrates connectivity between two separate AUTON OT OO ANS EEN 81 Figure 96 Data Acquisition during Manual Autopilot control This portion of data shows RC messages with complete RC commands from the remote controller and updated GPS positions 82 Figure 97 The General Gantt chart as predicted by the team in the beginning of October 2011 83 Figure 98 Portion of the waypoint insertion script This portion of code written in python inserted a target waypoint in x y meters relative to home into a paparazzi INSTANCE cccseceseeeneeeneeeseeenes 86 Figure 99 Waypoint Insertion Simulation This sequence of images demonstrates the insertion of the software team s navigation routine into a paparazzi simulation
221. ury that SARA Southern Arizona Rescue Association members suffered over 30 years These included two fractures a disrupted knee a shoulder dislocation and sprains requiring emergency department evaluation There were many more minor sprains and strains for which no assistance was needed Iserson et al 1989 The Southern Arizona Rescue Association is a good example of the risks rescuers face since they are exposed to a wide range of search and rescue scenarios including terrains like mountains bodies of water and dessert rescue Other injuries to rescuers included hypothermia and near drowning Iserson et al1989 Calling in a search and rescue team is also quite costly in the United States almost 60 000 000 was spent between 1992 and 2007 on search and rescue missions in America s national parks Heggie et al 2009 The high cost associated with search and rescue is due to the need for such large numbers of skilled people specialized equipment and the most important of resource of all time Search teams often have a wide search area to comb through looking for the lost or injured hikers Current search and rescue techniques include a lot of heavy machinery including but not limited to Wi cars trucks all terrain vehicles helicopters and planes Even under the best conditions these pieces of equipment require some skilled humans to pilot and or drive however the rough terrain compounds this need for skilled operators pilo
222. ustrates how much work needed to be completed on Robin before an Auto 1 test was even considered This extra work was the single most important factor that led to such a deviation from the original timeline This fact also affected Jay and Duck whose completion was scheduled for middle and end of C term respectively These deadlines were missed and thus far only Jay s airframe completion and RC flight milestones have been met Another setback regarding this was that the testing was scheduled to be done during the end of B term and into C term which in Worcester Massachusetts typically means difficult cold winter 83 weather The winter of 2011 2012 was abnormally mild which made testing significantly easier however windy days often kept the airframes grounded 4 2 Timeline with regards to Integration A key aspect to this project was the integration between the different teams The success of the integration is a defining factor of the success as the project as a whole All of the teams acknowledged this fact early in the project and as such the lines of communication were open from the start Issues regarding power draw weight and overall size of all of the components were carefully discussed between the teams to ensure the full system could be realized without any unrealistic requirements For example with power limited to that which could be carried by battery it would be unrealistic to power a full Intel core I7 computer plus all of
223. utopilot mode 47 Figure 57 The paparazzi configuration files allow for the complete configuration of the paparazzi autopilot system This allows for many different types of airframe structures and sensor combinations to be implemented A 51 Figure 58 Paparazzi autopilot system showing the ground control station coordinator Xbee for connecting the ground station to the Abee located on the Yapa2 cccceceseeeceeeeeeeeeeeeeeeeeeneeeenes 52 Figure 59 Adding in GPS subsystem This line of code from within the airframe configuration file will add the mediatek_diy GPS module to the atrame nnannnnnnnnnnnnennnensnerenrrrnrrrrrrerrrerrreerreee 52 Figure 60 The mediatek GPS located at the front Of RODIN ccececseeecceeeeeeeeeeeeeeeseeeeesaeeessaees 53 Figure 61 Mediatek GPS located at the front Of Joy 53 Figure 62 The thermopile section within the airframe configuration file This is where neutrals signs and other parameters are configured cccceecceeeceeeceeeceeeceeeseeeceeeseeeseeseeeseeseeeneeeneeeseeenes 54 Figure 63 Definition of the servos within the airframe configuration file These definitions set the neutrals minimum and maximum positions for the control surfaces of the UAV ceceeeee 55 Figure 64 Portion of the Telemetry configuration file This shows some of the available types of messages that can be sent across the xbee radios along with the rate in which they are SSES EIER 56 F
224. uture testing can straighten out the plane and then Auto 2 can be engaged to circle a target GPS position with a preconfigured radius Using the ground control station we can successfully connect two separate autopilot boards for data acquisition and autonomous control This can be expanded to more autopilot systems to satisfy our multi autonomous system design specification In order for our system to work with the software integration team the autopilot control system must feature the ability to update waypoints from an external source Using python we successfully inserted new target waypoints into a paparazzi simulation The waypoints inserted were generated from the path planning routine created by the software integration team m wass 542 355648 72 124753 1 0 andby Nav 222 elemasterTest AUTO totus AGL Blok e F CPS PFO Misc Settings amp RC Settin g 27 22 TelemasterTest mayda Time 1208 Ki if BIN a x 2227 31 TelemasterTest Holdin Stege 1208 K e 22 27 32 TelemasterTest Takeo ETA N A Wu params mode ir attitude auto throttle auto p 2229 33 TelemasterTest Standt Mark gon 4 0 000 Target Alt 50m qroll 0 6108 prod D A DN O O Leiter Crise Dash pyain t9509 19500 000 amp 9 9 900 Figure 9 Externally inserting waypoints CONFIG DECONFIG TARGET REFRESH CONNECT zZ 1NN grid rad cell rad units type oo feo meters p hexagonal init x inie ys init zs target alt Figure 10 Software tea
225. verify acceptable performance The step load goal is minimal overshoot with a damped response 0 30 60 o GE D H E 90 2 Es T D S 120 150 180 001 01 1 10 100 1000 FREQUENCY kHz 30058548 FIGURE 13 Modulator Gain and Phase T D keJ LU z z E T O a 10 100 1000 FREQUENCY kHz 30058549 FIGURE 14 Error Amplifier Gain and Phase www national com GAIN dB 10 100 1000 FREQUENCY kHz 30058550 FIGURE 15 Overall Loop Gain and Phase The plots shown in Figures 13 14 and 15 illustrate the gain and phase diagrams of the design example The overall band width is lower in a buck boost application due the compen sation challenges associated with the right half plane zero For a pure buck application the bandwidth could be much higher The LM5116 datasheet is a good reference for com pensation design of a pure buck mode regulator Bias Power Dissipation Reduction Buck or Buck boost regulators operating with high input volt age can dissipate an appreciable amount of power while supplying the required bias current of the IC The VCC regu lator must step down the input voltage VIN to a nominal VCC level of 7V The large voltage drop across the VCC regulator LM5118 translates into high power dissipation in the VCC regulator There are several techniques that can significantly reduce this bias regulator power dissipation Figures 16 and 17 depict two methods to bias the IC one from the output vol
226. very risky maneuver El Paso Country Search and Hescuel 2 Figure 3 The U S military s MQ 9 Reaper drone used for counter terrorism armed attacks US Air FOE 20 2 E 4 Figure 4 The project organization flow chart This illustrates how the different teams of Project WIND are organized and how they interact with each other This paper represents the work done by the Hardware Platform team in the lower left corner ccceccseecseeeceeeneeeseeeneeeneeeneeneeseeenaeenes 5 Figure 5 Warbird a type of scaled plane modeled after military aircrafts http www raidentech com new2O0t4uco4e bim 8 Figure 6 Sports Model a type of scaled plane intended for aerobatic flight http oroduct madeinchina com RC Airplane Model Sport Fun 46P_13077777 shtml 0 8 Figure 7 Sailplane a type of scaled plane with long thin wings used for gldmg 9 Figure 8 Airfoil Geometry Flat Bottom 10 Figure 9 Airfoil Geometry Symmetrical ccccceccceececeeeceececeeeceueeceueeceeecsusesseeseusecsueeseeesaeenaess 10 Figure 10 Airfoil Geometry HETIOKCG E 10 Figure 11 Diagram of how to measure the wing dlecdral 11 Figure 12 Lay out of a plane using the recommended ratios based on a 10 unit wing span 12 Figure 13 CAD of Goose s design before we started construction This CAD image doesn t include the Monokote that will cover the wings and tail and fill in the gaps cccceceseeeseeeseeeneeeneeeneeenes 16 Figu
227. vided they remain aflached to the model dunng flight Model rockets may be fown in accordance with the Natonal Model Rocketry Safety Code but may not be launched from model aircragt e Officially designated AMA Air Show Teams AST are authorized to use devices and practices as defined wifin the Team AMA Program Document AMA Document 2718 D Nol operap a turbine powered aircraft unless in compliance with the AMA turbine regulations AMA Document 570 A A Made aircraft will mot be down in AMA Sanctioned events air shows or model demonstrations unless a The arcat comirol system and pilot skiis have success y demonstrated all maneuvers intended or anticipated prior to the specific event gt An inexperienced pilot is assisted by an expenenced pilot A When and where required by rule helmets must be property worn and fastened They must be OSHA DOT ANSI SMELL or NOCSAE approved or E RADIO CONTROL 1 All pilots shall avoid fying directly over unprotected people vessels vehicles or stuctures and shall avoid endangerment of life and property of others 2 Asees radio equipment groundange check im accordance with manudacturer s recommendations will be completed betore the first flight of a new or repaired model aircrait 3 Atal fying sies a safety line s must be established in front of which all fying takes place AMA Document 4706 Re a Se E 0 At air shows of demonstrations a straight safety lime must be established IO An area away fro
228. ware and software 1 Not 5 Easily Versatility how much of the autopilot is modifiable 1 Not 5 All Implementation how easy it is to implement the autopilot 1 Easy 5 Difficult Ability how powerful the autopilot is 1 Low Performance 5 Great Performance 48 Table 6 Decision matrix for determining which autopilot system the team used Paparazzi ArduPilot Vawe 5 3 1 Availability 5 LS 1 Versatilit Implementation 2 Abilit Totals Based on the totals the team decided on Paparazzi due to its versatility and immediate availability 3 2 2 Hardware Selection After the autopilot system was chosen the microcontroller needed to be selected to run the autopilot software on the UAV The microcontroller will contain the portion of the paparazzi software which controls the plane during flight 3 2 2 1 Microcontroller Paparazzi autopilot software can compile onto ARM7 LPC21xx series and STM32 series controllers Within the Paparazzi documentation several boards are recommended to run Paparazzi The next step was to determine if the autopilot will run on a Paparazzi board develop a board to fit the teams specification or find a substitute board Finding a substitute board would be the cheapest option for the team however getting the proper hardware without extra capabilities from a third party would prove to be challenging Developing our own board would be the most complete solution for our project as
229. was left available for future teams to add the camera to the plane Until then the battery was strategically placed slightly forward to compensate for its absence 2 2 5 Jay Air Frame Modification With the previous experience from Robin the team was able to make better decisions when constructing and modifying Jay For instance when installing the fuel tank a decision was made to install it a quarter of the chord from the leading edge of the wing This ensured that the fuel tank will not interfere much with the center of gravity CG as the amount of fuel in the tank decreases during the flight This allowed balancing the plane and keeping a constant CG simpler In order to install the fuel tank a fuel tight box was made out of 1 8 inch plywood that was slightly larger than the tank as instructed by the manufacturer for a pressurized fuel tank This box was installed into the plane but to do this part of the rib structure had to be cut away Reinforcements were made to the areas cut away with 3 8 inch square dowels to help support the tank and the airframe as seen in Figures 29 and 30 Proteeting Foam for Gas Tank Figure 30 The fuel tank chamber in place in the body 26 The next modification was the installation of the quick disconnect valves for easy refueling of the plane After our experience with Robin it was found that there was a considerable amount of force needed to use the valves so appropriate measures for the installation wer
230. which primarily preformed color filtering and a blob detection algorithm to filter out the unnecessary frames from the camera The algorithms detected anomalies in the image which could potentially be humans and streams the possible hits to the base station for verification by a rescuer on the ground The main goal was to filter out all of the images that do not depict humans to reduce what would otherwise be an enormous amount of data from the cameras to a much more reasonable amount that a rescuer could easily observe and verify the UAVs findings The WPI communications team was responsible for creating a link between the different UAVs and the ground station They ultimately used a USRP2 software defined radio as the primary link between the UAV network and the base station To use the USRP2 effectively a computer capable of running Simulink was required to fly with the radio since Simulink is used to control features such as the frequency baud rate and syncing the two radios For communication between the UAVs a simple ad hoc wifi network IEEE 802 11 standard would connect the UAVs within the system The UNH communications team designed and built the actual radio to be used between the UAV network and the ground station The second team from UNH was responsible for creating a human interface utilizing a Microsoft Surface to create a large touch screen based graphical user interface GUI to control the UAVs This is the actual interface which w
231. x VIN VOUT 50 LA In buck boost mode the ramp current source is a function of the input voltage VIN per the following equation 5 pA Ramp buck boost J x VIN 50 uA Proper selection of the RAMP capacitor Champ depends up on the value of the output inductor L and the current sense resistor Rg For proper current emulation the sample and hold pedestal value and the ramp amplitude must have the same relative relationship to the actual inductor current That is BE Jm X L xA Cramp Gm XL C _ RAMP Ax Rs Where g is the ramp generator transconductance 5 A V and A is the current sense amplifier gain 10V V The ramp capacitor should be located very close to the device and con nected directly to the RAMP and AGND pins The relationship between the average inductor current and the pedestal value of the sampled inductor current can cause instability in certain operating conditions This instability is known as sub harmonic oscillation which occurs when the inductor ripple current does not return to its initial value by the start of the next switching cycle Sub harmonic oscillation is normally characterized by observing alternating wide and nar row pulses at the switch node Adding a fixed slope voltage ramp slope compensation to the current sense signal pre vents this oscillation The 50pA of offset current provided from the emulated current source adds enough slope compensa tion to the ramp
232. y Link RC Commands Plane Control Surfaces Data Telemetry cea ei Station AA Flight Plan Updates Navigation Contro Loop Altitude Contro Loop Ki Figure 51 Autopilot Flow Chart This chart represents the flow of how the autopilot system interfaces between the UAV in the air and the user controlled ground station 43 An autopilot system consists of autopilot software which is run on the UAV This software is in charge of flying the UAV and relaying sensor information to a ground station The autopilot software is preloaded with a flight plan that guides the UAV through a sequence of waypoints Based on the UAVs current position the altitude and navigation control loops manages the UAVs control surfaces so that it is directed to the next waypoint in the flight plan The ground control station is a portable computer running software that receives sensor readings from the UAV and presents it to the user via a graphical interface The ground control station provides the user the ability to update the UAVs flight plan during runtime in the event that the UAV needs to be redirected As a safety backup the autopilot system provides a method to interface a radio controller with the UAV which has the ability to switch off the autopilot and provide manual control There are many commercial and open source UAV autopilot solutions one commercial option and two open source options that are commonly used among profes

Design of an Autonomous Platform for Search and Rescue UAV

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