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Sky Vision: Final Design

1. weg E uew 9 a pas 32131334 134 December 7 2010 SKY VISION FINAL DESIGN Appendix M Microprocessor 135 December 7 2010 MicroProcessor DSPIC30F6015 Features ANM3H RES PAMAUL RES PNMAH RE SCK2CNERGE SD 2C NO ROG7 SDO2CN10 RG8 SSZCNIV RGI Vss Voo ANS OEB CS CN7 RBS ANA QEATCT CNE RBA ANXIND AN us 4 CNYRB ANO o REF e Hz RBO CNSRB3 ANZSSTCHPRHBEZ gt a k E Or u a is a L 2 SCH d 4 15 e m mn gt 5 m D 79058 LILILILI 3 225 M 5 ru I a 17 14 19 aA 2 24 M 3 32 FA RB6 gt s POCTEMUCIANEIOX POD EMUDVAN NRB Aven 1 2 23 2 AVS ANB RBA SKY VISION FINAL DESIGN L CIRXREO JEC Von C Vss WUPDNICN WyRD7 s SSO 5 4 3 OCO ICO CN WIRDS o2 L 2 OC NK CN IYRDA DIES OCA RD3 YS OC NUZ 5477 OC HEN 15 RD6 dsPIC30F6015 ANS RBS AN TO RB 10 ANTUIRB11 25 26 vss Vno AN12 RB12 AN TYRES 27 28 25 136 AN WRB 14 AN1 OCE P CN 12 RB 15 1 UPFOQUN 17 RF A UZIXCN TRE 5 49m PEMUD270CZ27RD 1 AB IM 45 450 AAE 43 2 s2 om 45 397 SEL 37 Ka 36 35 34 33 EMUC 7 SOSCOTICHICNORCE 14 EBMUD SOSCITACKCN RC 13 EMUC2Z OC URDO ICATINTA RD CXYINT3YRD 9 C2ZIFLTB INT2RD9 ICA FLTAANT RD8 vss OSC2 CLKO RC 5 OSC CLK Yoo SCURG2 SDARG3 EMUCS3 SCK 1NTORF6
2. 1uBISSP pug Jusose JO w 9 9c Xe uoee v ZL OL A LLL isalanTeg Od p Janod 51161 Bununoyy uoojjeg M OFZ unopeld uBIS S SL N OL uoneziliqejs sjey uongjo udi GOSS 15 Functional Descriptions of Subsystems Stabilization System The stabilization system will consist of two propellers mounted on a shaft A wind alignment plate will align the propellers in a direction parallel to the wind velocity The propellers will be capable of providing stability against wind induced lateral translation of balloon Input User control signal from user interface via motor control circuit see User Interface functional description for specifics on user input mechanism Output Stabilization of balloon maximum of 10 N thrust to stabilize against wind speed range specified in Requirements Specification and alignment of propellers with wind direction Communication System The communication system will remotely control the stabilization system and imaging rotation motors It will transmit a signal from the user interface via a DSPIC30F6015 microprocessor to a motor control circuit that determines stabilization thrust The signal will be transmitted wirelessly and will be in compliance with all relevant FCC communication standards and regulations Input Signal generated from remote control device on user interface and transmitted at radio frequency at 2 4 GHz Output Signal to a DSPIC30F6015 microprocessor mot
3. 107 December 7 2010 SKY VISION FINAL DESIGN oe oe oo Wind Force Calculation oe oe oo oo oe oo This program calculates the average wind force exerted on the balloon by a constant wind velocity AC Op AC AO AC AC oe oe oe D d drag COGIILILDIOIOHE oo oe oe oe oe oe E wind UTD NA A oo oe oe oe oe oe Assumption Balloon is spherical Assumption P 1 atm and T 20 C oe oe oe clear D 20 352507 Air temperature C F max zerost tengtbh T 1 V max zeros Lengtn T 1 for 1 1 length T rho 1 204 Density of air kg m 3 v 8 79302e 8 T i 1 34039e 5 Kinematic viscosity of air m 2 s V wind 010 0115 Relative wind speed range on balloon m s C d zeros length V wind 1 r 1 5 Radius of balloon assume spherical m Re V wind 2 r v Reynolds number for flow over a sphere Dine 2 Projected frontal area of spherical balloon for j 1 length V wind if Re j lt 4e5 oo 4 s 1075 slightly larger than Be cr C OC Vos e A a Tor Ilow Ee Be cr elseif Re j 4e5 amp amp Re j 1e6 2 417 Ved D a Tor Ilow Be gt Re or else c Al Us a d ror Re gt leo end V wind 2 j V wind j 2 Wind speed squared F wind 4 95 XD rbo V Wand 2 A S Wind eege N end F max i k max F wind V max 1 V wind k end plot V wind F wind title Wind Force N fontsize 14 xlabel
4. C 1 infrastructure to balloon stabilization system and Feb 8 Ph 2 imaging system attached to balloon S 3 2 Camera Build Build imaging system and Imaging and camera rotation Jan 18 J Ph camera rotation system subsystems connected Camera Feb 1 control circuitry built for both imaging and camera rotation S Imaging Build Build camera system Receiver transmitting circuitry Jan 18 S Camera Build of camera rotation Camera mounted to elevation 3 2 2 Rotation Build system rotation shaft and motor Motor connected to control circuitry Stabilization Build of stabilization Stabilization units built Jan 18 Ph 1 Build system to stabilize device assembled and mounted to Feb 1 C 2 platform frame Ph on O2 O2 S 3 4 Power Build Build power system to Power distribution system and P 1 J power device voltage regulating system built 2 and connected to battery S 3 5 Communication Build system to transmit Remote control circuitry built J 1 P Build user inputs outputs to from and ready to be mounted to user 2 device interface and aerial portion of platform S 3 6 Tether Build Build system to secure device to ground rope Rope attachment to balloon mechanism built User Interface Program software to Laptop displays live video feed Program receive inputs and display and records live video feed S 4 0 Device Testing Complete testing of each Test results of
5. Appendix K Booster Vision GearCam 131 December 7 2010 SKY VISION FINAL DESIGN BoosterVision GearCam BVGM 1 Features Small Size amp Light Weight Low Power Consumption Powered by 9 Volt Battery 2 4 Ghz Wireless Mini Color Camera with Audio from built in microphone Size 20mm W 20mm H 20mm D About 3 4 of an inch the size of a dime Comes with no tuning needed PLL receiver 12 volt ac dc supply for receiver and camera 9 volt battery clip and ac power pack for Mini GearCam Camera transmitter weight is only 50z 2 50z with 9 volt battery Field of view 60 degrees CMOS 380 TV lines of resolution sensor Range 300 700 feet in the air on an aircraft 300 500 feet on the ground Over 1 mile with the 14db patch antenna Receiver unit has SMA antenna connector with rubber duck antenna Use optional Hi Gain receiver antenna avalible for additional range Consumer use item no license needed FCC certified 132 December 7 2010 SKY VISION FINAL DESIGN Appendix L Balloon Data Sheet 133 SKY VISION FINAL DESIGN December 7 2010 N JESU pue uns 01 pssodxs usym Jspsg sdeys sy spjou U ssneaaq pespueuiuio3aJ SI uoneunBuuoa E3niasA eu ANY spesu 211dej moi 14 o suonesnByuc02 E3nia4 10 EJUOZUOY ay ur sjsued ay uj spew aq UBD sjeg uc Ex em FF UI EN Up uL 0190 EF Y NI 0ELT euimjoA unijaH 12 6 9 S 3U2d JO ON Ze WOLF x ui29913 DEF X 99F Ea Jud sarude1o Eug au ug
6. KIPPE rerjecuarn sa c 145 December 7 2010 SKY VISION FINAL DESIGN Appendix Q Auxiliary to USB Connector 146 December 7 2010 EasyCAP dealextreme Model DC60 Supports NTSC PAL Video format Supports high quality video resolution SKY VISION FINAL DESIGN Capture amp edit high quality video amp audio without sound card Include Professional and easy to learn amp used video editor software Ulead Video Studio 8 0 SE DVD Plug amp play Applying to internet conference net meeting Complies With Universal Serial Bus Specification Rev 2 0 USB bus power ormats record in DVD R RW DVD id DVD Video Support Brightness Contrast Hue and Saturation control 147 December 7 2010 SKY VISION FINAL DESIGN Appendix R Remote Control System 148 December 7 2010 SKY VISION FINAL DESIGN NZ HIT 721 5 2 4GHz Radio Control System Complete Set included 2 4G Receiver gt 24 Features TECHNOLOGY Digital Proportional Control In DH No more interferance 6 Channel Radio Power Saving Ball amp Hiller On Sale Now 2 System Mixing Control cz E Great for 3D Flying 17 COMPUTER PROGRAMMABLE 41418111 O e pa rn diii LL re N 6 CHANNEL BAD Comm FTES BASIC PARAMETER MODEL NAME 6 CHANNELS TRANSMITTERS MODEL NO FS CT6X e CHANNELS 6 CHANNELS e MODE TYPE AIRPLA
7. TTL type Q and inverted Q inputs control a classic H bridge circuit rated at 50 volts and about 10 amps The circuit can control power and direction of a DC motor 80 December 7 2010 SKY VISION FINAL DESIGN 12v SO VOLTS 0 02 OHMS RATING 2 2K H IRF4905 fp ei TOP VIEW Q pa ve CZ Ol IRF3707 IRF3707 INVERTED Q DRIVE r 185401 115401 r WITH BOTH INPUTS Gos LOW MOTOR IS OFF 50 VOLTS 0 01 OHMS RATING 50 VOLTS 0 01 OHMS RATING www discovercircuits com all rights reserved DRAWN BY DAVE JOHNSON DAVID JOHNSON AND ASSOCIATES HIGH EFFICIENCY H BRIDGE MOTOR ORIVER KSE a HBRIDGE2 DSN CNN CU ZI e e ENS 177 Figure 65 H Bridge circuit to be used 81 December 7 2010 SKY VISION FINAL DESIGN User Interface Design The user interface consists of a device on which the user can view the live video feed transmitted from the imaging system on the balloon Initially it was thought that an LCD screen and corresponding circuitry would be used to view the live video feed However it was found that analog output to USB output connectors were cost effective simple to use and readily available see Appendix Q see Figure 66 below Figure 66 Analog to USB connector The USB connector supports video formatting and high quality video resolution and complies with USB Specification Rev 2 0 see Appendix Q Due to the ease with which the video format will be converted to USB a user s
8. The elevation rotation and azimuth rotation will be provided independent of the stabilization system i i i i i i Balloon i i i i Balloon l i i i i Axis parallel e to ground TE s i i on Elevation rotation CR rotatlon i plane Figure 1 Azimuth and elevation rotation Sky Vision will be operated by the customer using a portable user interface device The user interface will provide three important functions 1 control of the imaging system and simultaneous viewing of the live video feed 2 control of the stabilization system and 3 control of deflation of the balloon To use Sky Vision the user will remove the system from storage and ensure the aerial platform 1s correctly secured to the tethering system prior to inflation with helium gas The 11 December 7 2010 SKY VISION FINAL DESIGN platform will then be connected to the power source and both the platform and user interface will be powered on The user will then add the required volume of helium gas to inflate the platform note that the customer will provide any required helium gas except for that required by system development and testing The tethering system will then be slowly released allowing Sky Vision to slowly rise to the desired altitude Once Sky Vision has reached the desired altitude the user may then utilize the imaging and stabilization systems to obtain the desired field of view for the live video fe
9. U J3 MC7806 LINE BEE 6V BM Figure 51 Schematic of central power system 67 December 7 2010 SKY VISION FINAL DESIGN Voltage regulators will be used to drop the 11 1 V down to 6 V and 5 V Voltage regulator MC7806 will be used to drop the voltage from 11 1 V to 6 V and voltage regulator LM7805 will be used to drop the voltage from 11 1 V to 5 V see Appendix P for data sheets of voltage regulators The two servomotors providing imaging rotation will draw the 6 V from the power supply circuit Figure 51 The output of 6V will connect to the power supply of servomotors control circuit The 5 V power branch will provide the necessary power to microprocessor and the decoder for the controller receiver The output will connect with the power supply pin of microprocessor and the decoder The reason that the smaller capacity battery will not be in parallel with the other four batteries was obtained by analyzing the work down by the previous blimp senior design group The prior group found that electrical interference noise from the propeller motors is significant and will interfere with the camera to minimize this noise the power supply of the imaging rotation motors and microprocessor will be separated from the power supply of the propeller motors Although the central battery can also provide the surplus power to the propeller motors when they are in parallel the surplus power of 9 21 Wh 3 15Wh 223 03Wh for each propeller
10. aircraft The field of view of the camera 1s 60 degrees and it provides CMOS 380 TV lines of resolution The range is said to be 91 44 to 213 36 meters 300 to 700 feet in the air on an aircraft by the manufacturer The camera transmission distance was successfully tested the range was found to be greater than 45 72 meters 150 feet outdoors on the ground The zoom on the camera must be adjusted manually by twisting the lens with a small tool The solution to the focusing complication 1s to focus the camera at infinity this 1s the method used by cheap disposable cameras This method will allow all objects at a significant distance to be in focus Because objects from a distance of approximately 36 6 meters 120 feet will be recorded this method will provide adequate focus for the imaging system The operation time of the camera was also tested using a new 9 volt battery the operation time was found to be greater than one hour These results surpass the requirement of 30 minutes of live video feed Receiver The Booster Vision camera includes a no tuning needed PLL Phase locked Loop receiver A phase locked loop is a control system that tries to generate an output signal whose phase 1s related to the phase of the input reference signal The end goal of this control process is to keep the input phases matched It has a SMA Sub millimeter Array antenna connector with rubber duck antenna The input to this component is the wirelessly transmi
11. use high quality thread deforming lock nuts or doubled jam nuts to prevent connections from vibrating loose Part Dimensions Thickness Available Sonor in inches Tolerance Durometer in inches Range 0 19 x 12 x 14 401070 Class 1 X tra flex sheet 22 10 Unit Price in USA Dol a Y _5to49 50 199 200 1 for Purchase 3 100 to 249 40 to 70 40 to 70 40 to 70 SCHEER 1 40 to 70 8 9 cs z 0 04 x 4 x 6 0 06 x 4 x 6 0 06 x 4 x 6 0 08 x6x 6 1 10 x 6 x 12 1 10 x 6 x 12 1 8 x 6 x 12 1 8 x 6 x 12 olx 8 3 5 71 Class 2 with PSA 1 side 10 38 6 d 1 109 110 40 to 70 40 to 70 40 to 70 40 to 70 98 7 25 G Dr E 8 830 8 9 ss 93 s Glass 3 with PSA 1 side oe 914 99 73 me 99 Class 3 with PSA 1 s kal 1 10 x 12 x 12 40 to 70 3340 on TE Lu oux 30 to 70 n vo 30 to 70 28 30 to 70 30 to 70 30 to 70 30 to 70 30 to 70 30 to 70 0212018 3 16x 12x12 1 4 x 12 x 12 3 8 x 12 x 12 1 2 x 12 x 12 17 03 20 025 4 21 88 sse an an 25 81 34 28 43 88 32 2 es 5m re sem 3 4 x 12 x 12 1x12x12 1 50 x 12 x 12 E 6 0 38 9 68 m n 110 91 sous 200 B S 1 8 x 24 x 24 0224018 3 16 x 24 x 24 0224025 1 4x24x24 0224037 3 8x24x24 4050 1 2x24x24 5 8 x 24 x 24 3 4 x 24 x 24 40 to 70 40 to 70 30 to 70 30 to 70 30 to 70 30 t
12. 10 Cengel and Cimbala 2006 At the critical Reynolds number the flow over the sphere sharply transitions from laminar flow to turbulent flow causing a commensurate reduction in drag force Corresponding to the change in the flow regime of the fluid 1s a proportionate change in the drag coefficient across the sphere in the laminar regime Cp 0 5 and in the turbulent regime Cp 0 2 Cengel and Cimbala 2006 For the discussion to be useful it is necessary to determine the sensitivity of the drag force to changes in air temperature as kinematic viscosity varies greatly with temperature variation An analytical expression for the change in kinematic viscosity with temperature change was obtained by plotting empirical data points in Microsoft Excel and then performing a regression analysis on the data points The data for kinematic viscosity of air was obtained from the properties charts provided by Cengel and Cimbala 2006 The results of the regression are shown below in Figure 5 Kinematic Viscosity v Temperature E GE 9302E 08x 1 34039E 05 0 4 y m 2 s L o Q 2 gt fe ded OU S x Air Temperature deg C Figure 5 Kinematic Viscosity vs Temperature 24 December 7 2010 SKY VISION FINAL DESIGN It is evident from Figure 5 that kinematic viscosity of air at a pressure of 1 atm varies linearly with temperature changes The linear regression equation obtained in Excel 1s shown in the upper righ
13. 122 WeRASL Ja Ver WRAI0 LA CSDVRGI2 Ta j n n CSCKHRGM NZYRA CNZZIRAG AonL 125 Aves 120 ANWRBS L 27 AHH A IO 15 SKY VISION FINAL DESIGN 5s 268 zc sss C k n We u cr ml Zz z z zz BB SS 8 x ax 350553 s x 1 0 65 67 e z n n n dsPIC30F6014A OWEN EVRDA ON TWRD 13 AL CAIRDE 33 L1 OCHRDS VL IOCVRD2 SE g w wWtuppnu TI AN IWOGHBIEN TIRE mat TW 22222 222 S2 z 2 z z IW A 35 LIUCNAYRI LNCN2VRD UTOQCN INR 61 C EMUDZIOC2 RDI H L se UPDUCNINRES L 140 BAUC ISCSCOTICKCNORC 14 SMUD T SOSCIICM YRC 13 EMUCZOC RDO ICA RD CX RD O ICZ RD9 IC RDB INTA RATE INT 3 RA vet OSCHCLKORCIS OSC3 CLK H Ki VOD SCL RG2 SDA amp RGS3 EMUCA3 SCK SOIIRFT EMUD3 SDO RFB UIRXRF2 UTTX RFS NTORFS Figure 63 Microprocessor pin out diagram The simplicity and familiarity of an H Bridge to control the motors powering the stabilization system makes the use of an H Bridge an attractive option for motor control The issue with the H Bridge circuit 1s that the propellers in the stabilization system require as much as 10 Amps As of yet two H Bridge circuits that claim to handle 10 A have been found Though using an IC version of an H Bridge would simplify the design no IC versions of an H Bridge have been found which can handle the current requirements of the system A
14. 15 Notice requirements No person may operate an unshielded moored balloon or kite more than 150 feet above the surface of the earth unless at least 24 hours before beginning the operation he gives the following information to the FAA ATC facility that 1s nearest to the place of intended operation a The names and addresses of the owners and operators b The size of the balloon or the size and weight of the kite c The location of the operation d The height above the surface of the earth at which the balloon or kite 1s to be operated e The date time and duration of the operation 101 17 Lighting and marking requirements a No person may operate a moored balloon or kite between sunset and sunrise unless the balloon or kite and its mooring lines are lighted so as to give a visual warning equal to that required for obstructions to air navigation in the FAA publication Obstruction Marking and Lighting b No person may operate a moored balloon or kite between sunrise and sunset unless its mooring lines have colored pennants or streamers attached at not more than 50 foot intervals beginning at 150 feet above the surface of the earth and visible for at least one mile Sec 6 c Department of Transportation Act 49 U S C 1655 c Doc No 1580 28 FR 6722 June 29 1963 as amended by Amdt 101 4 39 FR 22252 June 21 1974 103 December 7 2010 SKY VISION FINAL DESIGN 101 19 Rapid deflation device No p
15. 5 m s Note however that the transition from laminar to turbulent flow 1s not as abrupt a phenomenon as Figure 6 portrays In order to approximate the drag over a wide range of wind velocities the drag coefficient had to be approximated as being either laminar or turbulent with no intermediary values In reality Figure 6 1s a smoother curve with a lower maximum peak The approximation used above 1s therefore a very liberal approximation of wind drag Stabilization Unit Selection The next step 1n the stabilization system design was to select appropriate stabilization units to generate the required minimum of 10 N of thrust Two options were initially considered ducted fans and open air propellers Ducted fans consist of a motor and propeller blade surrounded by a low clearance cylindrical duct see Figure 7 Open air propellers however do not have the cylindrical duct encasing the propeller blade r Exterior duct encasing motor Interior propeller removed from duct Figure 7 Ducted fan www ductedfans com These two options were considered because a large market radio controlled aircraft already existed which relied on the use of those two forms of stabilization units Open air propellers were chosen over ducted fans for two primary reasons First of all ducted fans producing the same thrust as an open air propeller consumed much more power upwards of 900 26 December 7 2010 SKY VISION FINAL DESIGN W for the
16. Low supply current 370A 3V Ultra low 0 11 A standby current Deflnable recognition authority True serlal encoding Applications Include Keyless Entry Door and Gate Openers Security Systems Remote Device Control Car Alarms Starters Remote Status Monitoring Call Paging Systems Excellent nolse Immunity Selectable baud rates No programmer required Direct serial Interface Small SMD package Latched or momentary outputs Encoder ID output by decoder Figure 57 Decoder features left and receiver IC right 74 December 7 2010 SKY VISION FINAL DESIGN HXM LR D SEL BAUDO SEL BAUDI LINX 0 630 RF MODULE RAM 418 LR S 1 LOT 10000 Figure 58 Wiring schematic and IC dimensions for receiver and decoder This wiring schematic will allow for simple integration of the receiver with the control circuitry The dimensions show that the receiver chip will be large enough to solder by hand The LR series receiver features long range low cost and low power consumption It uses a direct serial interface and can detect data at rates up to 10 000 bps The only external RF component required 1s the antenna which will be described at a later point This allows for simple integration of the system even by engineers without previous RF experience The receiver s advanced synthesized architecture achieves a sensitivity of 112dBm which provides a 5 10 times improvement in range over previous solutions When paired with
17. SKY VISION FINAL DESIGN Appendix J Sorbothane Vibration Isolation Material 126 December 7 2010 SKY VISION FINAL DESIGN Sorbothane Polymer Sheet Stock X Tra Flex Sheet X Tra Flex Sheet 1s molded with hemispherical bumps The hemispheres permit the material to flex more easily and allow for soft deformation under load Overall sheet thickness is approximately 0 185 inch The hemispheres are approximately 0 09 high and 0 12 diameter X Tra Flex sheets are easier to apply to curved and irregular surfaces and provide a softer spring rate Pressure Sensitive Adhesives Selected Sizes max width 6 1nches are offered with Pressure Sensitive Adhesive PSA on one side Die Cutting Sheet stock up to 0 25 inch thick with or without PSA can be die cut at additional cost Die cut materials will have a concave edge Consult factory on costs Water Jet Cutting Sheet stock of any thickness can be water jet cut Water jet cut materials will have a clean edge Consult factory on costs Gaskets Sorbothane is a popular material for gaskets because of its chemical resistance conformability to irregular surfaces low creep and reusability Its natural tackiness makes it easy to install Gaskets can be knife cut scissor cut die cut molded or water jet cut Special Sizes Colors and Thicknesses The factory can pour special shapes colors and thicknesses Tooling costs can be as low as 500 USD per mold The tooling charge is no
18. Since the drag force of the wind on the balloon drops drastically at 3 m s wind values between 4 and 5 m s only require low values of power to the propeller motors to stabilize against wind Dividing the runtime calculated in Table 5 for a worst case scenario of 3 m s winds by the frequency of occurrence for the worst case range of 2 5 3 m s wind range gives an approximate expected runtime of 112 6 minutes The approximation however assumed that the propeller motors are not running except when the wind speed is in the worst case scenario range and also that each propeller motor is connected to a single 11 1 V 2 5 A h battery To account for compensating for wind speeds at all times not merely the worst case scenario it is assumed that the influence of all other wind speeds on battery longevity 1s equal to the influence on battery longevity of the worst case wind speed range Since both wind speed ranges have the same effect the prior mentioned run time accounting for only the worst case range 1s essentially halved causing a run time of 56 3 minutes Since the projected run time 1s less than that dictated by the Requirements Specification 60 min further capacity must be added to the power supply system The further capacity will be accomplished by adding another battery of equal capacity to each propeller motor The addition of more power than necessary will incorporate a factor of safety into the power supply 65 December 7 2010 SKY
19. The device will be flown in 5 m s or greater winds to test flight stability To verify flight stability the positioning and camera systems should still be capable of locking onto an object on the ground and remaining locked onto that object for a duration of 5 minutes with 5 m s wind present To allow for wind variability a 2 week testing period will be selected and the device tested at different states of wind speed The extended testing time allows for adjustments to be made to the device as well as to account for random wind speed variation The communication system will be tested by flying the device at its maximum height of 36 6 meters and ensuring communication 1s not lost The dimensions of the deflated device will be measured to ensure that both the volume and dimensions of the device do not exceed the specified dimension volume requirements The dimensions will be measured using a standard measuring tape December 7 2010 SKY VISION FINAL DESIGN System Design December 7 2010 SKY VISION FINAL DESIGN Background Sky Vision will meet the needs provided in the Requirements Specification by being far less expensive than the current methods used to obtain aerial images Sky Vision aerial imaging will be an alternative to renting or purchasing expensive equipment outright Using Sky Vision will be much more convenient for the customer since the system can be easily transported to the required location Sky Vision will use heliu
20. VISION FINAL DESIGN system which will allow for days on which the wind speed distribution does not fit the Rayleigh probability density function curve and instead has a higher frequency of occurrence of the worst case wind speed range Estimating Power Required by Other Power Consuming Systems The four other systems requiring power other than the camera which operates on its own 9 V power supply are the two servomotors providing imaging rotation 6 V and 0 5 A see Appendix H the microprocessor 5 V and 48 mA see Appendix N the decoder for the controller receiver 5 V and 670 uA see Appendix T and the controller receiver itself 5 V and 5 2 mA see Appendix T The combined power of all the aforementioned components is 6 3 W therefore 30 minutes of run time for the system requires 3 15 W h Due to the light weight of the lithium polymer batteries a lithium polymer battery will also be used to provide power to all other power consuming components Since only 3 15 W h are needed another 3 cell lithium polymer battery with lower energy 11 1 V 830 mAh will be used as opposed to the 3 cell lithium polymer batteries used by the stabilization system The battery selected for providing power to all other power consuming systems 1s a 3 cell 11 1 V 830 mAh lithium polymer battery with the following capacity in W h Capacity 11 1 V 0 83 Ah 2 9 24W h Eg Since the required capacity was 3 15 W h the 3 cell 11 1 V 830 mAh lithium
21. components No production tuning necessary required except antenna LR Series Transmitter RXM LR LR Series Receiver 315 418 standard 433MHz MS Series MS Series encoders and decoders are ideal for remote control and command security keyless entry and a host of similar applications The encoder IC allows the status of up to eight buttons or contacts to be transferred with high level of uniqueness via an HF or infrared link The decoder then reproduces the button states on its outputs The MS Series has several unique features that make it superior to competitive solutions These include the ability to easily define user groups and assign permissions to individual output lines Outputs can be latched or momentary and secure address assignments can be instantly changed without cumbersome DIP switches or cut traces The large twenty four bit address size provides for over 16 000 000 unique addresses making transmissions highly unique and secure and minimizing the possibility of multiple devices having conflicting addresses The decoder can learn up to 40 different encoders and outputs the originating encoder ID for logging or identification Housed in tiny 20 pin SSOP packages MS Series parts feature low supply voltage and low current consumption Features Secure 2 possible addresses s Excellent noise immunity B data lines Selectable baud rates Low 2 0 5 5V operating voltage No programmer required Low supply c
22. in the purchasing decision included adequate number of transmission channels adequate transmission range and a price low enough to fit within Sky Vision s budget Table 7 Decision Matrix for transmitter Decision Matrix for Transmitter Firefly Fireblade 205 Trans 204 Trans OTX 315 HH LR amp CMD HHLR MD 315 Manufacturer Rfsolutions Rfsolutions Rfsolutions Rfsolutions Linx Tech Linx Tech Receiver Size 1 1 2 2 5 Receiver Price 2 7 5 Price 2 3 A Range 2 5 3 4 Channel 5 5 5 3 3 The OTX by Linx Technologies was selected as the replacement transmitter for the system see Appendix S it is also called the MS long range handheld transmitter The handheld transmitter cost less than 40 00 had a transmission range of 304 m 1000 ft and comes with an eight button option This device is available to purchase in a number of different available frequencies The linxtechnologies com website gives a very helpful recommendation for this exact topic The website says 315MHz 1s primarily used for remote keyless entry and garage door openers As a result this frequency 1s somewhat crowded In addition the FCC allowed power is lower than for other frequencies and selection of antennas is limited 418MHz is a good to use in the U S as it 1s not very crowed Therefore it has less chance of encountering interference and performs better 433 92MHz 1s not good in the U S due to the chance of interference from amateur radio and the nearby
23. inclined an angle The buoyant force acts through the centroid of the balloon which in this simplified case also corresponds to the center of gravity G The drag force Fp acts through the centroid and the line of action of the thrust force 1s assumed to act through the center of gravity this assumption 1s valid since the center of gravity can always be shifted to a desired location by adding an appropriate amount of mass at the required distance From Figure 2 the differential arc length de can be related to the differential lengths of the coordinate axes by the following relation ds dx dy 2 ax Eq 1 To determine the deflection angle 0 of the cable it is first necessary to sum forces in the x and y directions The sum of the forces in the x direction is and the sum of the forces in the y direction 1s Fg Wys Tcos 0 Eq 3 21 December 7 2010 SKY VISION FINAL DESIGN The above expressions can be simplified by realizing that sin 0 and cos Setting ax the following simplified results for the force balance equations d l l I l gt p and inserting the latter expressions and also Eq 1 into the force balance equations yields T N Eq 4 F W 0 Eq 5 B Sys 1 p2 q Once Fp Fr Fg and Ms are quantified the above nonlinear expressions can be solved in MATLAB using the code provided in Appendix B The goal of the simulation is to check the respon
24. interchange so important to improved rc airplane propeller designs There is continuous evolution in rc aircraft design and engine performance Consequently propeller design must continuously evolve as well to keep pace with these improving technologies Due to APC s excellent quality and consistent performance APC Landing Products rc airplane propellers are perfect for any electric rc application from parkflyers to 3D aerobatics to scale rc aircraft 110 December 7 2010 SKY VISION FINAL DESIGN Note This rc airplane propeller 1s designed only for use with electric motors Do not attempt to use this propeller with glo or gas powered engines APC Motor Shaft Adapter Bushings Inside Diameter 4 01mm 0 158in 6 02mm 0 237in 3 25mm 5 00mm 7 95mm 0 128in 0 197in 0 313in 111 December 7 2010 SKY VISION FINAL DESIGN Appendix E Hacker A20 20L Motor Data Sheet 112 December 7 2010 SKY VISION FINAL DESIGN Hacker A20 20L Motor The A20 motors are small outrunner of our series and provides great efficiency and light weight They re ideal for small electric airplanes up to 600g 21oz Featuring a Slotted 14 pole outrunner design The Curved Neodym Magnets offer a perfect gap from the inside of the rotor for optimal power and efficiency Spare shafts Backmount Prop adapter and all screws are included 3 5mm gold bullet connectors are provided not with A20 S The motors are available in different Len
25. its stand alone functions the board can also be connected to a PC via a USB connection Included software audibly and visually demonstrates the powerful capabilities of the system Technical support for the kit and all on board Linx products is included Master System Contains Master System Features 2 MS Handheld transmitters User prototyping area 2MS Serles decoders Breakout header 2 LR Serles recelvers On board 3V regulator 1 CW Serles antenna HD Serles with 315MHz ysB Interface I Pre assembled boards for Immediate use 1 9V battery 2 CONREVSMA001 RP SMA connectors Demonstration software Demonstration software CD Listed quantity includes those populated on evaluation boards CP Compact rice LR Long Range MS Compact Handheld Transmitter Master Development System 149 95 MS Long Range Handheld Transmitter Master Development System 149 95 2 315 418 standard 433MHz Figure 56 Transmitter master development kit Even though this all inclusive kit is not within budget it did allow for an efficient way of selecting compatible components The necessary parts were selected based on the recommendations laid out in both this development system and also on the website First of all aLR series receiver and MS series decoder were selected They are shown below along with a wiring schematic of the pins Features Secure 224 possible addresses 8 data lines Low 2 0 5 5V operating voltage
26. linxtechnologies com Total 69 82 80 December 7 2010 SKY VISION FINAL DESIGN User Interface System Component Item to Purchase Quantity Total Vendor AUX to USB EasyCAP captures video amp audio 1 9 00 dealextreme com AUS to USB free shipping 1 0 00 dealextreme com screen user s own laptop 1 0 00 user Total 9 00 Microprocessor and Control Circuitry Component Item to Purchase Quantity Total Vendor IMicroprocessor free sample DSPIC3OF6015 3 0 00 microchip com Evaluation Board SchmartBoard 202 0011 01 2 51 09 schmartboard com Total 51 09 87 December 7 2010 SKY VISION FINAL DESIGN Project Management December 7 2010 SKY VISION FINAL DESIGN Fall 2010 Schedule Analysis Many unanticipated elements influenced the realization of the Fall 2010 Schedule Gantt Chart Work Breakdown Schedule and Network Diagram The primary factor influencing the realization of the Fall 2010 Schedule was the influence of recursive design elements and system interdependencies The main design of all of the subsystems was directly influenced by the design of at least one other subsystem For example the power system relied on the design of the stabilization system However the thrust generated by the propellers hinged upon how much power they were supplied Many system interdependencies such as the example provided above shifted the design from a linear process to a recursive process The design had to be based on es
27. locations most important to consider are going to be where the tether 1s attached and where the propellers are attached The infrastructure has to be able to support the combined 10 N thrust force generated by the propellers Also the infrastructure has to withstand the tethering force These issues will be considered when choosing the material to construct the platform and also the methods of attachment The material selected for the infrastructure is PVC A finite element analysis FEA shows the connection to the tether and to the propeller assemblies will withstand the force from the propeller assemblies The results of the analysis are shown in Figures 35 and 36 The yield strength of PVC 1s approximately 55 15 MPa Engineering Toolbox The maximum stress on the infrastructure 1s shown in Figure 35 to be 3 8 MPa yielding a factor of safety 1s 14 There 1s a 5 N force at each end of the pipe where the four bolts are connected to the PVC pipe The stress could be reduced by shortening the length of the PVC f needed The PVC 1s 1 27 cm diameter 1 2 inch The deflection of the infrastructure due to the 10 N force is minimal The deflection is approximately 0 00716 meters as shown in Figure 36 53 December 7 2010 SKY VISION FINAL DESIGN von Mises Nim 2 3 822 470 8 3 504 223 3 3 185 976 0 2 867 728 5 2 549 481 0 2 231 233 5 1 812 986 1 1 594 738 8 1 276 491 3 858 243 9 639 996 4 321 749 0 3 501 6 Yield strengt
28. memory 10 000 erase write cycle min for industrial temperature range 100K typical Data EEPROM memory 100 000 erase write cycle min for industrial temperature range 1M typical Self reprogrammable under software control Power on Reset POR Power up Timer PWRT and Oscillator Start up Timer OST Flexible Watchdog Timer WDT with on chip low power RC oscillator for reliable operation Fail Safe clock monitor operation Detects clock failure and switches to on chip low power RC oscillator Programmable code protection In Circuit Serial Programming ICSP Programmable Brown out Detection and Reset generation Selectable Power Management modes Sleep Idle and Alternate Clock modes CMOS Technology Low power high speed Flash technology Wide operating voltage range 2 5V to 5 5V Industrial and Extended temperature ranges Low power consumption 138 December 7 2010 SKY VISION FINAL DESIGN Appendix N Microprocessor Power Demands 139 December 7 2010 SKY VISION FINAL DESIGN Microprocessor dsPIC30F6010A 6015 24 0 ELECTRICAL CHARACTERISTICS This section provides an overview of dsPICSOF electrical characteristic
29. subsystems Feb 1 Ph P subsystem modification recommendations Mar 8 d S 4 Platform Test the platform to ensure Results of balloon lift and Feb 8 C 1 Testing it can support subsystems stability tests modification Feb 22 Ph 2 recommendations m m N Camera Testing Ensure camera can provide Results of camera imaging and J live feed and rotate through rotation tests modification specified angle recommendations Imaging Ensure the camera can Results of imaging testing Testing provide satisfactory video modification recommendations feed Actual range of rotation Ph E nl Ru t m 94 December 7 2010 SKY VISION FINAL DESIGN 4 2 2 Rotation specified elevation range specified modification Feb 15 Testing recommendations Stabilization Ensure stabilization units Actual thrust output quantified Testing compensate for wind drag modification recommendations and angular deflection S 4 4 Power Testing Ensure power outputs can Actual power output quantified provide power for all modification recommendations subsystems S 4 5 Communication Ensure system can Actual communication range Testing communicate to device at quantified modification max altitude and recommendations receive transmit user signals S 4 6 Tether Testing Ensure tether can support Actual reeling force quantified Feb 227 Cd S 4 7 User Interface Ensure user interface can Test prope
30. the selected long range transmitter a reliable wireless link is formed This link is capable of transferring over distances of up to 3000 feet Applications operating at slower transmission speeds and shorter distances will still benefit from the increased reliability and noise immunity The receiver has an operating voltage of 5 volts and current of 5 2 milliamps The MS series decoder is designed to function alongside the encoder already embedded in the handheld controller It is ideal for remote control and command keyless entry and many other similar applications As shown in the wiring schematic above the decoder has eight outputs On each of these outputs the decoder reproduces the button states on its outputs Each output then becomes an input into the microprocessor chip The fact that there 1s one output per control button will greatly simplify the programming needed on the microprocessor This decoder unlike those made by many competitors includes the ability to assign user groups to 75 December 7 2010 SKY VISION FINAL DESIGN individual output lines It can recognize up to 40 different encoders but only one encoder will be utilized by the Sky Vision system Outputs can be either latched or momentary Like the receiver the decoder features low voltage supply of 5 volts and low current consumption of only 670 micro amps An antenna is a necessary part of the communication system The specific type recommended for the 418 tran
31. weight size ratio of more than three ounces per square inch on any surface of the package determined by dividing the total weight in ounces of the payload package by the area in square inches of its smallest surface 11 Carries a payload package that weighs more than six pounds 111 Carries a payload of two or more packages that weighs more than 12 pounds or 1v Uses a rope or other device for suspension of the payload that requires an impact force of more than 50 pounds to separate the suspended payload from the balloon b For the purposes of this part a gyroglider attached to a vehicle on the surface of the earth is considered to be a kite Doc No 1580 28 FR 6721 June 29 1963 as amended by Amdt 101 1 101 December 7 2010 SKY VISION FINAL DESIGN 29 FR 46 Jan 3 1964 Amdt 101 3 35 FR 8213 May 26 1970 101 3 Waivers No person may conduct operations that require a deviation from this part except under a certificate of waiver issued by the Administrator Doc No 1580 28 FR 6721 June 29 1963 101 5 Operations in prohibited or restricted areas No person may operate a moored balloon kite unmanned rocket or unmanned free balloon in a prohibited or restricted area unless he has permission from the using or controlling agency as appropriate Amdt 101 1 29 FR 46 Jan 3 1964 101 7 Hazardous operations a No person may operate any moored balloon kite unmanned rocket or unmanned free b
32. 0 R11 100K 100K 100K 100K 100K lt 100K 100K Figure 55 Wiring diagram of transmitter 73 December 7 2010 SKY VISION FINAL DESIGN In addition to the transmitter a corresponding receiver and decoder are necessary to pick up and utilize the transmitted signal The selected transmitter was available to purchase in a full kit The kit in the below figure cost approximately 150 00 USD which unfortunately does not fall within budget limitations MS Handheld Transmitter Master Development System The Linx MS Handheld transmitters are ideal for remote control and command applications Available in 315 418 standard or 433 92MHz versions they have been pre certified for FCC Part 15 Industry Canada and European CE 433 92MHz compliance This dramatically reduces development cost and time to market When combined with an LR Series receiver the transmitters can operate at distances of up to 1 000 feet LR or 750 feet CP This comprehensive development system is designed to assist in the rapid evaluation and integration of the Handheld transmitters The all inclusive kit features a pre assembled evaluation board which includes everything needed to quickly test the operation of the transmitter receiver and decoder When you are ready to begin development a convenient prototyping area with breakout headers and regulated power supply on the receiver decoder board allows for rapid testing and interface In addition to
33. 25 inch hollow braid polypropylene This material can withstand up to 4404 N 990 Ibf The force on the reeling system 1s calculated by subtracting the system weight from the buoyant force cause by the displacement of air by the balloon Equations 31 and 32 show the required reeling force calculations Fret Fpuoyancy Mpe 9 Msys g Eq 31 Fret ES Dair g Voailoon PHe Vhalloon g Msys g Eq 32 59 December 7 2010 SKY VISION FINAL DESIGN From Equations 31 and 32 the net force on the reeling system is 11 9 N this 1s also the required force of the user to reel in the system A Bayco deluxe reel with stand will be used as the structure it is shown in Figure 46 Figure 46 Reeling system for tether rope As stated in the FAA regulations provided in Appendix A a bright colored flag must be attached for every 15 24 meters 50 feet of tethering cable released Plastic pennant flags will be attached to the tethering cable to fulfill this requirement and since only 36 6 m of cable 1s required only two pennants will be needed The mass of the plastic pennant flags 1s negligible 60 December 7 2010 SKY VISION FINAL DESIGN Power Supply Design Overview The objective of the power supply is to fulfill the following requirement from the Requirements Specification document The power system should allow for a minimum of 1 hour flight time and also a minimum of 30 minutes of live video not necessarily co
34. 64 Re j lt 1e6 0 447 Ehe a C 1 for ilow Be gt Re Gr else CAT 0 2 a L amp Tor Be le9 end V wind 2 V wind j 2 Wind speed squared E wind g 0 9 C d J pair V wind 2 A 2 Wind z ree MW end end vw 0 1 Desired velocity to analyze motion of balloon F wael Initializes force of wind to unrealistic value so it 5 will be known if no value is found for i l length V wind if V wind i vw F w F wind i break elseif i length V wind amp amp F w 1 error Wind speed out of specified range end end PB pair d o pI IR og 5 Buoyant force on balloon mb 2 5 Mass of balloon kg msys 4 System mass kg h 30 Height of balloon m o I msys h a 6 Inertia about tether ground cl h F w I oi G2 e F B gt msys g h I 05 G9 5 0 a p d EPLI SE E c4 F w h I o EES Torce should be equal 16 drag Toree 01 wind t 0 0 01 120 118 December 7 2010 SKY VISION FINAL DESIGN eNumerical solution options odeset Using default options for ode solver phiO 0 0 initial conditions on thdot 0 and th 0 time phi vals ode45 G8pendulum balloon fcn t phi0 options cl c2 c3 c4 plot time abs phi vals 1 r title Wind Response Fontsize 14 xlabel Time s Fontsize 12 ylabel texlabel phi deg Fontsize 12 function dphi pendulum balloon fcn t phi0 cl c2 c4 oe Need to provide function with th and
35. Detailed schematic and final report on device capabilities System capability specifications December 7 2010 SKY VISION FINAL DESIGN Aerial surveillance device User interface Non supplied parts Helium gas will be provided for testing purposes but the customer will be responsible for obtaining helium gas for later flight AA user provided laptop computer will be necessary to view the live video feed User Manual Remove device from storage and ensure the tether system 1s correctly connected to the blimp 2 Connect the power system to the tethering system and power on the device and user interface 3 Add necessary helium gas to the blimp until fully inflated User must supply helium gas 4 Slowly extend tethering line to allow blimp to rise to desired elevation 5 Obtain desired imaging using camera and blimp positioning systems done via the user interface 6 Slowly reel in tethering line until blimp has reached ground level Maintenance ensure blimp 1s intact with no leaks Maintenance when reeling in tethering line check visually for damaged areas 7 Remove gas from blimp and disconnect tether system from power system 8 Place system in storage Test Plans The power system will be connected to the imaging and stabilization systems and tested at a short vertical height for 1 hour to verify power needs this includes 30 min of video feed testing The time duration will be tested using a commercia
36. Fury EDF ducted fan on www ductedfans com Second ducted fans were generally much more expensive and also heavier than open air propellers producing the same thrust Ducted fans are used in the remote controlled aircraft market because they are capable of producing values of thrust which could only be obtained otherwise by using very large conventional propellers Predicting the thrust generated by an open air propeller is a very complex problem The thrust force generated by the propeller 1s due to a pressure difference between the inlet and outlet surfaces of the propeller The pressure difference 1s due to some very complicated effects The pressure change 1s essentially generated because the propeller blade is a rotating wing with a varying angle of attack and changing airfoil shape Using Bernoulli s Law in combination with the fact that force 1s equal to change in pressure times area yields the following result for a rotating blade modeled as a thin disk Fr 5 PD Ve Ve Eq 8 where Cp and p were defined previously The complication arises in that neither the exit velocity V nor the inlet velocity V are known The only other known method for analytically determining the thrust force generated by a certain propeller 1s to use a finite element fluid dynamics simulation based upon advanced airfoil theory However this analysis has been performed by radio control enthusiasts with knowledge of aerospace engineering and placed online i
37. HARDING UNIVERSITY Sky Vision Final Design Philip Varney Cristina Belew Julianne Pettey Peng Yang 12 7 2010 December 7 2010 SKY VISION FINAL DESIGN Table of Contents R guirements EENEG H EE 5 Problem E LE 5 Regler ee 6 E TC OCS em ee ee beet 6 User E E 7 CSE e E 7 POV SCCM DES ston odo pa 53499499993 82 90 0099 0102440900 r vo Ol odo o k ot 9 Back Orol AO DEPRESII ooo 10 A QU TRE TETTE ETT 11 Organization and Management etat Ee Rr ER IN DEPO EE In eX Ex As Ibex st Eu v 13 Da Doc DIa E 15 Functional Descriptions Of Subsystems z B 16 Pinal DD GSO mc ie 19 Stabilization System Desisn ME 20 Mechanical Imaging Desen 37 Piecttcal Imagens Desien E 45 SE ege E E 48 Tanen uU 59 Power o yoten Des E MT T 6l Communication System Dest Sts anne ae 70 User latenace RE E 82 DC EE 83 loud ag 84 SUSY sle DL BUS ee 85 Project Manas smeli sos een ern ein RUD PEE 88 EE 89 Fall 2010 Work Breakdown Schedule seen on hl o bk noo 90 Ball 2010 Network Diagrami Auge Eege kod ek aa 91 Fall 2010 Schedule Ana EE 92 SDERIC 20 Oant C ba ee ENEE 93 Spring 2011 Work Breakdown Schedule s sssssssesssssse nn 94 Spring 2011 Network DIAgEOIT ua se au 96 BREICTENEES soo ae TOT LLL LL LLLI DSL TRES 97 Decembe
38. IGN Appendix H Hitec HS 81 Servomotor Datasheet 122 December 7 2010 SKY VISION FINAL DESIGN ANNOUNCED SPECIFICATION OF HS 81 SUB MICRO SERVO 1 TECHNICAL VALUES CONTROL SYSTEM OPERATING VOLTAGE RANGE OPERATING TEMPERATURE RANGE TEST VOLTAGE OPERATING SPEED STALL TORQUE OPERATING ANGLE DIRECTION IDLE CURRENT RUNNING CURRENT DEAD BAND WIDTH CONNECTOR WIRE LENGTH DIMENSIONS WEIGHT 2 FEATURES 3 POLE FERRITE MOTOR HYBRID I C DIRECT POTENTIOMETER DRIVE PULSE WIDTH CONTROL 1500usec NEUTRAL 4 8V TO 6 0V 209C TO 60 C AT 4 8V AT 6 0V 0 115ec 60 AT NO LOAD 0 09sec 60 AT NO LOAD 2 6kg cm 36 100z in 3kg cm 4 1 660z in 40 ONE SIDE PULSE TRAVELING 400usec CLOCK WISE PULSE TRAVELING 1500 TO 1900usec 8 8mA 9 1mA 220mA AT NO LOAD 280mA AT NOLOAD Busec 160mm 6 28in 29 8x12x29 6mm 1 17x0 47x1 16in 16 69 0 580z 123 December 7 2010 SKY VISION FINAL DESIGN Appendix I Transmissibility MATLAB Code 124 December 7 2010 SKY VISION FINAL DESIGN o 5 Transmissibility Curves w wit 020 0133 zo OU 4100 EE EE EA 0 1 for i 1 length z for j l length w wn x 1 9 s 1 2 2 1 w wn g 2 0 5 Sqrt L w wn j 2 2 2 z i w wn j 2 end end plot w wn x title Transmissibilirty Fontsize 14 xlabel texlabel omega omega n Fontsize 14 ylabel texlabel X W PA F tr F 0 Fontsise l14 125 December 7 2010
39. January 8 4 3 8 February 8 9 4 0 March 9 6 4 3 April 9 4 0 May 7 6 3 4 June 1 1 3 2 July 6 7 3 0 August 6 3 2 8 September 6 6 3 0 October 6 8 3 0 November 8 3 6 December 8 1 3 6 Though the average wind speed in the aforementioned months 1s approximately 4 0 m s the actual wind speed varies about the average speed according to the Rayleigh distribution Gipe 2004 The Rayleigh distribution for wind speed 1s fv z av 2 era Eq 34 where dV is the wind speed bin width V is the speed of the wind speed bin and V is the average wind speed Plotting the above function in MATLAB for a wind speed of 4 m s yields the following distribution for Little Rock Arkansas 64 December 7 2010 SKY VISION FINAL DESIGN Rayleigh VVind Distribution for Average VVind Speed 4 m s m 4 Y 0 0179 0 008 Frequency of ccurrence e k 0 006 0 004 0 002 Wind Speed m s Figure 48 Rayleigh wind distribution for average wind speed of 4 m s Summing the frequency of occurrences of a range of wind speed bins provides the frequency of occurrence of a range of wind speeds Since 3 m s is a worst case scenario summing from 2 5 m s to 3 m s will give a frequency of occurrence of the worst case wind speed range The frequency of occurrence for a range 2 5 m s to 3 m s is 11 found using MATLAB Therefore even on a day with an average wind speed of 4 m s the worst case range occurs only 11 of the total time
40. Long Range Handheld Transmitter The Linx OTX HH LR8 MS Long Range Handheld Transmitter is ideal for general purpose remote control and command applications that require longer transmission distances This unit has been pre certified for FCC Part 15 Industry Canada and European CE 433 92MHz only compliance reducing costs and time to market Available in 315 418 standard or 433 92MHz this small remote has a transmission range of up to 1 000 feet when combined with the LR or LT Series receiver The transmitter unit can be configured with 1 to 8 buttons and the keypad and labeling can be modified to meet specific OEM customer requirements Ease of use and security are dramatically enhanced by the on board MS Series encoder which allows instant creation of up to 16 777 216 224 unique addresses without cumbersome DIP switches or cut traces When paired with a MS Series decoder transmitter identity can be determined and button permissions established The unit uses a single 3V CR2032 lithium button cell Standard Part OTX HH LR8 MS 200 999 315 418 standard 433MHz 1 000 4 999 POWER SUPPLY Operating Voltage supply Current Power Down Current TRANSMITTER SECTION Transmit Frequency Range OTX 315 HH LR8 MS OTX 418 HH LR8 MS OTX 433 HH LH8 MS Center Frequency Accuracy ENVIRONMENTAL Operating Temperature Hange 152 December 7 2010 SKY VISION FINAL DESIGN Appendix T Receiver 153 Decem
41. NE HELICOPTER GLIDER e STICK MODE LEFT HAND OR RIGHT HAND MODULATION FREQUENCY MODULATION MODULE FREQUENCY 35MHZ 40MHz 72MHz 2 4GHz ANTENNA LENGTH 115CM 26MM CODE TYPE PPM GFSK POWER 12 VDC RF POWER LESS THAN 0 8W WEIGHT 575 GRAMS SIZE 189 72 218MM 149 December 7 2010 SKY VISION FINAL DESIGN Features 1 6 Channel 2 4GHz R C Transmitter Complete Set w Receiver Features complete Forward Backward Left Right Up Down amp Pitch Control RUDDER AILERON ELEVATOR Pitch AND THROTTLE New longer 3K battery mounting plate connects to main frame It makes the center of gravity closed to rotor blade and can adjust the center of gravity according to the weight of battery it reduces the correction when the heli rolling Rotor head for precision and smooth movements Great stable and sensitive mixing lever design Can display the great stability and precision for 3D flight Using Ball and Hiller two systems mixing control Through simple structure of Ball control system power saving of Hiller system and CCPM control can simultaneously control 3 servo for AILE EVLE PIT 3 actions This control system is great for 3D flying control and extending life cycle of Servos Software for Raido Download Here Click Here COMPUTER PROGRAMMABLE 150 December 7 2010 SKY VISION FINAL DESIGN Appendix S Transmitter 151 December 7 2010 SKY VISION FINAL DESIGN MS
42. U RXSDIS RF EMUD3U TWSDO RFI December 7 2010 SKY VISION FINAL DESIGN Parameter Name Value Architecture 16 bit CPU Speed MIPS 30 Memory Type Flash Program Memory KB 144 RAM Bytes 8 192 Temperature Range C 40 to 125 Operating Voltage Range V 2 9 10 95 95 I O Pins 52 Pin Count 64 System Management Features PBOR LVD Internal Oscillator 7 37 MHz 512 kHz nanoWatt Features Fast Wake Fast Control Digital Communication Peripherals 2 UART 2 SPI 1 I2C Analog Peripherals 1 A D 16x10 bit 1000 ksps Comparators 0 CAN type CAN Capture Compare PWM Peripherals 8 8 Motor Control PWM Channels 8 Quatrature Encoder Interface QEI 1 Timers 5 x 16 bit 2 x 32 bit Parallel Port GPIO Hardware RTCC No DMA 0 Features High Performance Modified RISC CPU Modified Harvard architecture 16 x 16 bit working register array C compiler optimized instruction set architecture 84 base instructions with flexible addressing modes 24 bit wide instructions 16 bit wide data path Up to 30 MIPs operation DC to 40 MHz external clock input 4 MHz 10 MHz oscillator input with PLL active 4x 8x 16x Peripheral and External interrupt sources 8 user selectable priority levels for each interrupt 4 processor exceptions and software traps Primary and Alternate interrupt Vector Tables DSP Engine Features Modulo and Bit Reversed Addressing modes Two 40 bit wide accumula
43. Wind Velocity m s fontsize 1l2 ylabel Wind Force N fontsize 12 108 December 7 2010 SKY VISION FINAL DESIGN Appendix D APCIO x 4 7 Propeller Data Sheet 109 December 7 2010 SKY VISION FINAL DESIGN APC 10x4 7 SE Slow Flyer Electric RC Airplane Composite Propeller d d in cotes not Now ques ibis erf mmm T RE eles Product Description APC Landing Products Slow Flyer RC electric composite model airplane propeller A10047SF LP 10047SF is designed for use with electric rc airplanes APC Slow Flyer props are not for high power applications but are specifically crafted for low power use Includes locating rings in various sizes and instructions on adaptation procedures APC Landing Products electric model airplane propellers have enjoyed strong acceptance and growth since their introduction in 1989 They are especially popular in rc pattern flying and rc airplane racing events The performance and low noise advantages are largely spawned by the precision methods APC Landing Products uses to design and manufacture APC electric rc airplane propellers APC 10x4 7 SF Slow Flyer Electric RC Airplane Composite Propeller Specifications e Length 10 inches e Pitch 4 7 inches per revolution e Type Slow Flyer Electric e Material 1 Piece Composite e Use Electric RC Airplanes APC Landing Products preserves a close rapport with the rc aircraft competition community to benefit from technical
44. Y VISION FINAL DESIGN Electrical Imaging Design Overview The purpose of the electronic portion of the imaging system 1s to collect a live aerial video feed and transmit that feed to the ground to be made viewable on the user interface The Requirements Specification document states that the video feed will have the capability to provide a minimum of 30 minutes of live video feed to the user interface System Components The electronic component of the camera imaging system as a whole consists of three parts on the balloon and five parts on the ground The parts in the air are the camera itself a 2 4GHz PLL receiver a 12 volt supply for the receiver a SMA sub millimeter array antenna connector with rubber duck antenna and two standard RCA audio video cables that connect the video output to the user interface Figure 28 Imaging system is a basic block diagram describing the internal interfacing of the system Video Receiver AUX to USB Coaxial Connector Camera 12 Volts Figure 28 Imaging system The bold black arrows indicate the direction of flow of data and power The gray object represents the camera transmitter which wirelessly transmits the video feed to the user interface The wireless broadcasting 1s represented by the blue lines The green receiver collects the signal through the rubber encased antenna Its video and audio outputs can be seen as the red and yellow connections The blue boxes represent pow
45. alloon in a manner that creates a hazard to other persons or their property b No person operating any moored balloon kite unmanned rocket or unmanned free balloon may allow an object to be dropped there from if such action creates a hazard to other persons or their property Sec 6 c Department of Transportation Act 49 U S C 1655 c Doc No 12800 Amdt 101 4 39 FR 22252 June 21 1974 Subpart B Moored Balloons and Kites Source Docket No 1580 28 FR 6722 June 29 1963 unless otherwise noted 101 11 Applicability This subpart applies to the operation of moored balloons and kites However a person operating a moored balloon or kite within a restricted area must comply only with 101 19 and with additional limitations imposed by the using or controlling agency as appropriate 101 13 Operating limitations a Except as provided in paragraph b of this section no person may operate a moored balloon or kite 102 December 7 2010 SKY VISION FINAL DESIGN 1 Less than 500 feet from the base of any cloud 2 More than 500 feet above the surface of the earth 3 From an area where the ground visibility 1s less than three miles or 4 Within five miles of the boundary of any airport b Paragraph a of this section does not apply to the operation of a balloon or kite below the top of any structure and within 250 feet of 1t 1f that shielded operation does not obscure any lighting on the structure 101
46. approximately 3 m s 62 December 7 2010 SKY VISION FINAL DESIGN The first step in determining battery life was to determine a relationship between supplied power and battery longevity Battery longevity for a 2 5 A h battery can be obtained via the following formula Battery Longevity E 60 Eq 33 Psupplied h In Equation 33 Psupptiea 1s the power supplied by the battery to the motors dependent on thrust force needed the voltage of the batteries 1s constant at 11 1 V and the capacity of the batteries is 2 5 Ah Table 5 provides data for battery longevity versus wind speed where the power supplied to each motor is proportional to the wind speed on the balloon Table 5 Battery longevity Battery Longevity for one 2 5 Ah Battery Longevity for two 2 5 Ah Wind Speed m s batteries per motor minutes batteries per motor minutes It is evident from Table 5 that a runtime of 60 minutes as specified in the Requirements Specification can only be obtained via a single 2 5 A h battery when the average wind speed over the entire hour is approximately 0 7 m s 1 5 mi h Table 6 contains average wind speed data per month for Little Rock Arkansas It 1s clear from the table that the average wind speed in March thru April when testing occurs 1s approximately 4 0 m s 63 December 7 2010 SKY VISION FINAL DESIGN Table 6 Average wind speed for Little Rock AR Average Wind Speed Average Wind Speed mph m s
47. as approximately equal to the rotation rate of the propeller the unbalanced mass In this case a vibration damping system can be added to remove mechanical energy from the vibration in the form of heat The imaging system can be modeled as a mass having a moving base y t The damping system in both cases can be thought of as a vibration isolation system where the goal is to minimize the force F transmitted through to the base Transmissibility 1s defined as Fer _ K VT The magnitude of the actual periodic force is Fa which occurs at a frequency of w The Eq 26 damping ratio depends on the mass of the system the natural frequency wp and the damping coefficient c Important image stabilization attributes can be obtained from making observations of the frequency response of the transmissibility The non dimensional response of the system shown in Figure 26 is shown below in Figure 27 for varying values of See Appendix I for the MATLAB code used to generate Figure 27 Transmissibility 12 Resonance bad ar So co Increasing damping ratio good IXGw VA F F c Figure 27 Transmissibility 43 December 7 2010 SKY VISION FINAL DESIGN Since the goal is to minimize transmissibility it 1s desirable to have low damping coefficients and low natural frequencies The worst possible scenario occurs when the natural frequency 1s equal to the driving frequency at this point the transmitted force
48. at cos w 1 and is dependent on the mass of the shaft length of the shaft and mass of the camera The MATLAB code provided in Appendix G calculates the holding torque across all values of y Mechanical Imaging System Component Selection Three possible mechanisms for accomplishing the elevation and azimuth rotation are available stepper motors brushless DC direct current motors and servomotors Stepper motors are available in different angular step rotations per pulse As step size decreases control of the camera location increases in precision Stepper motors seem to be heavier than servomotors but also less complex The next option for camera rotation is brushless DC motors 39 December 7 2010 SKY VISION FINAL DESIGN these are less suitable for the task at hand since they offer the least amount of control over position Also there is no accurate way of measuring how far the output shaft has rotated The last option servomotors are feedback controlled motors which receive a pulse width modulation PWM signal instructing them to rotate the shaft to a specified angular position Low torque servomotors are lightweight and generally low n cost but are also the most complicated of the rotation mechanisms One concern with using a rotating motor is supplying the power to the second motor which is rotating relative to the control signal and power supply assuming power supply is placed apart from motor In order to avoid exces
49. becomes much larger than the actual driving force causing large disturbances in the system The solution to the high frequency vibration problem 1s therefore to change the system parameters to decrease the natural frequency and also change the damping to increase the value of This can be accomplished by changing the mounting infrastructure of the stabilization units and imaging system by using materials specifically designed for vibration 1solation such as Sorbothane Appendix J The manufacturer of the Hitec HS 81 servomotor provides an accessory kit for attaching the servomotors to the supporting structure which comes with rubber dampers designed to mount onto the side bolt connections on the servomotor see Appendix J 1 Since the actual excitation frequency causing the high frequency vibration of the system is unknown and can only be measured via testing matching material properties of a damper material to the characteristics of the excitation provides little useful design information For this reason the rubber dampers included in the servomotor accessory kit will be used to damp the high frequency vibration in the system If 1t 1s discovered during testing that the dampers are not fulfilling their purpose further analysis will be performed and a second material selected to provide damping The simplicity and very low cost of rubber dampers permit the adaptation of the design at a late stage during testing 44 December 7 2010 SK
50. ber 7 2010 SKY VISION FINAL DESIGN LR Series Long Range Low Cost RF Data Module The LR Series is ideal for the wireless transfer of serial data control or command information in the favorable 260 470MHz band The receiver s advanced synthesized superhet architecture achieves an outstanding typical sensitivity of 112dBm which provides a 5 10 times improvement in range over previous solutions The transmitter s synthesized architecture minimizes the effects of antenna loading providing a more stable consistent performance When paired a reliable wireless link is formed capable of transferring data at rates of up to 10 000bps over distances of up to 3 000 feet Applications operating at short distances or lower data rates will also benefit from increased link reliability and superior noise immunity Housed in tiny reflow compatible SMD packages the LR Series modules are footprint compatible with the popular LC Series the transmitter pin out is slightly different allowing existing users an instant path to improved range and lower cost No external components are required except an antenna allowing for easy integration even by engineers without previous RF experience Long range Low power consumptlon Low cost Wide temperature range 40 to 70 C PLL synthesized architecture Compact surface mount package Direct serlal Interface Adjustable transmitter output power Data rates to 10 000bps RSSI and power down functions No external RF
51. cess begins when the user manipulates a hand held controller These movements are converted to a signal that 1s wirelessly transmitted at a frequency originally planned to be 2 4GHz This signal is picked up by a receiver mounted on the system This receiver 1s interfaced with a microprocessor which interprets the signal from the ground The microprocessor outputs the appropriate pulse width modulated signal to the motor control circuit The motor control circuit sends power in the correct direction through the propeller motors and camera rotation motors causing the system and camera to respond according to the user s instruction System Components The communication system can be broken down into three major components The first component consists of the hand held radio controller and includes both the transmitter and receiver A microprocessor makes up the second major component It must be programmed to interface with the receiver and interpret the input signal into outputs that can be used by the motors The third major component consists of all the necessary motor control circuitry which sends the necessary power to the motors The figure below 1s a basic block diagram describing the original internal interfacing of this system before significant design changes were made Power u kod Ground Controller Receiver Figure 52 Communication system 70 December 7 2010 SKY VISION FINAL DESIGN Controller The original contro
52. cos F5h W sind h E R hcos Fghsin Eq 15 The inertia about point O is Z i MR Msysh mys h Eg 16 The mass of the entire system is m and the mass of the balloon itself is mp Since the tether length h gt R the inertia of the balloon about its own center of gravity is negligible The drag forces Fy and Fp can be obtained by inserting the proper terms for velocity wind velocity and rotational velocity of balloon respectively into Equation 6 The thrust force 1s equal to the wind drag F in order to provide stability The buoyant force is equal to the weight of the air 35 December 7 2010 SKY VISION FINAL DESIGN displaced by the balloon Using an ordinary differential equation solver in MATLAB the response to Equation 15 was obtained see Appendix F 1 for MATLAB code used and shown below 1s Figure 19 Wind Response 1 8 1 6 1 4 1 2 p deg 0 8 0 6 0 4 0 2 0 20 40 DU DU 100 120 Time s Figure 19 System response about tethering attachment From Figure 19 1t 1s clear that the period of the system 1s approximately 15 seconds and that the maximum value of the angular displacement 0 is approximately 1 7 Due to a combination of the slow response of the system large period and small angular displacement the quick response time of the elevation rotation servomotor see Appendix H should suffice to allow the user to manually compensate for slow disturbances of the image Pro
53. d Mounting undecided Motors shipping 1 10 00 rctoys com Propellers shipping included above 1 0 00 rctoys com Total 107 80 Main Power Supply Component Item to Purchase Quantity Total Vendor Camera Pwr 9 Volt Battery 2 6 00 Kroger MotorPwr Lipo 11 1V 2500mah 10 12C 4 S80 00 maxxprod com Motor Pwr Shipping 1 7 95 maxxprod com Receiver Pwr 12 Volt AC DC Supply 1 0 00 boostervision com Motor Pwr Lipo 11 1V 830mah 10 12C 1 10 00 maxxprod com Total 103 95 December 7 2010 SKY VISION FINAL DESIGN Tether System Component Item to Purchase Quantity Total Vendor Reel Bayco Deluxe 150 Reel with Stand 1 8 48 Lowes Tether Cord 1 4 polypropylene 120 feet 1 6 00 knotandrope com Tether Cord shipping 1 5 50 knotandrope com Total 19 98 Platform System Mounting PVCPipe O 5inch by 5feet 1 1 30 Lowes Balloon 7 feet Urethane Balloon 1 265 00 southernballoonworks com Balloon shipping 1 20 00 southernballoonworks com Helium 220 cubicfeet tank 1 104 00 AirGas Helium Rental fee per day 14 5 60 AirGas Total 395 90 Communication System Component Item to Purchase Quantity Total Vendor Transmitter MS Long Rang Handheld Transmitter 1 32 80 linxtechnologies com Decoder MS series decoder 2 6 20 linxtechnologies com Receiver LR Series Receiver 2 19 60 linxtechnologies com Attena CW series whip attena 1 5 74 linxtechnologies com Connector Attena connector 1 2 30 linxtechnologies com Connector Attena connector 1 3 18
54. d or camera should allow for both 360 of azimuth rotation and 90 of elevation rotation of the camera in order to provide a stabilized image Elevation Rotation Motor Design In order to select the motor to provide 90 of elevation rotation of the camera the required holding torque of the motor is needed The holding torque is the static torque required by the motor to keep the output shaft in the same location A simplified free body diagram of the elevation rotation motor is shown below in Figure 21 with the camera modeled as a point mass on the end of the L shaped shaft 37 December 7 2010 SKY VISION FINAL DESIGN Figure 21 Free body diagram of elevation rotation motor In Figure 21 V represents the elevation rotation angle 0 V lt 90 T is the torque generated by the motor output shaft m 1s the mass of the camera components m is the mass of the portion of the output shaft changing orientation and the x4y4z4 set of axes is fixed to the motor Point A designates the joint between the two portions of the output shaft A free body diagram of the portion of the output shaft changing orientation 1s shown below in Figure 22 21 X mcg Figure 22 Elevation rotation shaft free body diagram The length of the output shaft is L the force reactions at the fixed permanent joint are A Ay and Az and the associated moments not shown are My My and M The xyz axes are fixed to the rotating output shaft and rota
55. degrees s or 0 05 rad s From the data sheet of the azimuth rotation servomotor Appendix H the angular speed of the servomotor has a maximum value of 9 52 rad s Since the angular speed of the servomotor is much greater than the maximum angular speed of the system the user will be able to adjust the camera position manually to compensate for the very slow oscillation of the system The slow oscillation of the system 1s also evident from the very large period of the system 44 s In addition to modeling the rotation of the system due to the wind alignment plate the system was also modeled as an inverted pendulum in order to quantify the rotation of the system about the base of the tethering system on the ground To simplify the analysis the tether cable was always assumed to be taut and straight see free body diagram below in Figure 18 Figure 18 System modeled as inverted pendulum In Figure 18 the length of the tethering cable is denoted by h the rotation from the vertical position is the point of tether attachment is point O Fp is the damping drag present in the system Fr is the thrust force generated by both propellers Fg is the buoyant force W is the system weight and F is the drag force induced by the wind The system weight and buoyant force are both assumed to act through the centroid of the balloon of radius R Summing moments in the z direction about point O yielded the following equation of motion 1 0 Fr h
56. e The platform was approximately 50 more than anticipated for two primary reasons helium was more expensive than estimated and also the cost of the balloon was increased due to selecting a balloon with premade load attachments The communication budget is approximately the same as that initially estimated The user interface was much cheaper than initially estimated because a user supplied laptop will be used as the user interface eliminating the need for an LCD display The estimated budget for the control circuitry combination microprocessor and transmitter was very inaccurate due to the decision to use a microprocessor to control the stabilization system and mechanical imaging system 84 December 7 2010 SKY VISION FINAL DESIGN Subsystem Budgets Imaging System 85 Component Item to Purchase Quantity Total Vendor Camera 2 4 ghz Mini GearCam 1 69 95 boostervision com Camera shipping 1 8 95 boostervision com Receiver no tuning needed PLL receiver 1 0 00 boostervision com Receiver 12 volt ac dc supply 1 0 00 boostervision com Camera 9 volt battery clip 1 0 00 boostervision com Connector Mini Coaxial Plug size H 1 3 23 Radio Shack Motors Hitec HS 81 2 34 00 rctoys com Motor Attachment Hitec HS 81 Kit 2 8 00 rctoys com Total 124 13 Stabilization System Component Item to Purchase Quantity Total Vendor Motors Hacker A20 20L 2 89 90 rctoys com Propeller APCSF 10x 4 7 inch 2 7 90 rctoys com Casing 2 undecide
57. e specifications includes test results 91 SKY VISION FINAL DESIGN December 7 2010 ubiseg 14 uoneiueuimnaor 92 u6jd Haa pue ubiseg waists E suongneayiseds uawanbay Vote eid 0107 Te UEISLIJ JIOMIIN SKY VISION FINAL DESIGN December 7 2010 me O oo ow O re wm EECH oem mm EE mmm o wer ooo o II m me mom rose mmm Leer sm _ LESE wma o wem omm feme mmm v omm oe jme wes Less Samom o LLOZISLIZ Bunss uoneoiunuiuo al EE wmm y om omm om SE LLOZ UE LLOZILIZ LLOZ BL L ping volsindaug D LLOZ uz LLOZIBL L PINE ewe el PINE woned m C m cmm IIIS IRIS PII IS DII uoreung US vej GWEN XSET TLOZ Suridg HEH pueg 93 December 7 2010 SKY VISION FINAL DESIGN Spring 2011 Work Breakdown Schedule Activity Description Deliverables Duration People Checkpoints days S 1 0 Project Ensure project is Description of team member Jan 18 Ph Management completed correctly and on task completion May 5th time S 2 0 Documentation Ensure changes and Engineering notebooks A3 Jan 18 Ph P progress is recorded reports design reports May 5 J C S 3 0 Device Build Complete builds of All of subsystems connected as Jan 18 Ph P subsystems specified by design Feb 22 JC S 3 1 Platform Build Connect mounting Mounting brackets for tether Jan 18
58. ed Once imaging 1s complete the user will slowly reel in the device while visually inspecting the tether for damage Once the platform has reached ground level the user will inspect it to ensure the integrity of the platform has not been compromised The valve system will then be used to remove the helium gas from the platform Following helium gas removal the system will be powered off and returned to storage Platform Selection Three options were considered concerning the type of platform the aerial imaging system would be mounted on The three choices were a fixed wing aircraft a fully mobile and un tethered blimp or a tethered spherical balloon with limited propulsion mobility A downside of the fixed wing aircraft 1s that it would have been too difficult to design in the allotted time also it would not have provided the necessary level of imaging stability One disadvantage of the spherical balloon 1s that it would not have given the freedom for the user to move to the desired location needed for imaging The first choice considered was the blimp this option would have provided an easier method for moving the blimp to the desired imaging location dictated by the user However the problem which arose when looking at blimp shaped balloons was the price most small blimp shaped balloons were between 500 and 1000 The decision matrix utilized to decide on a platform is shown in Table 1 Table 1 Decision matrix between balloon airplane a
59. een 0 m and approximately 152 meters above sea level Searcy Arkansas 1s at approximately 81 meters above sea level www usclimatedata com Since the system 1s only going to rise to a maximum elevation of 36 6 meters above ground see Requirements Specification the total elevation above sea level will be 127 meters A significant deviation from the original standard air pressure does not occur until an elevation of 914 meters 1s reached since the elevation of Searcy 1s much less than this then it can be deduced that the effect of elevation change on lift capacity 1s negligible Altitude change effects on Standard Air Pressure Standard Air Pressure kPa 1000 1200 Altitude meters Figure 33 Altitude change vs Standard Air Pressure 21 December 7 2010 SKY VISION FINAL DESIGN The amount of mass a spherical balloon can lift 1s proportional to the volume of the balloon Since the volume of the balloon 1s a cubic function of the balloon radius the amount of mass the system can lift increases exponentially as the balloon radius increases Therefore a slight increase 1n the diameter gives a large increase in lifting capabilities shown in Figure 34 Maximum System Mass Gi L i L all bel L gt Uu E 3 E x Radius m Figure 34 Maximum lifting capabilities determined by radius of balloon The equation to determine the required lifting capability of the balloon is 3 3Msys 47 Pai
60. ely 5 N of thrust or half of the desired value of 10 N of thrust For this reason two propellers were chosen rather than one larger propeller as to minimize power consumption The next step was to select stabilization system components propeller blade as well as driving motor to provide the necessary 10 N of stabilization thrust Two attributes must be considered in the selection of a propeller blade The first of these attributes 1s the diameter of the blade A general rule can be gleaned from the observation that a propeller is nothing more than a momentum changing device as the momentum of a control volume of air 1s changed thrust 1s generated So as diameter 1s increased air flow 1s increased which in turn increases thrust The second attribute to consider is the pitch of the propeller A propeller is essentially an air screw and as such the pitch of the propeller 1s defined as the distance the propeller would move through the air given one turn of the blade So once again as pitch is increased more air is moved through the blade resulting in increased thrust Taking into account the above observations on pitch and diameter the thrust calculators were used to both estimate thrust generated by different propellers of varying dimensions and also to analyze how much power would need to be given to the propeller to provide the given thrust It was found that the propeller which provided adequate thrust while remaining within reasonable
61. em User Interface The user interface consists of the user provided laptop used to view the live video feed The live video feed will be viewable on the user interface which will be a user supplied laptop computer Input AUX signal from transmitter Output Viewing of live video feed on laptop computer via USB 18 December 7 2010 SKY VISION FINAL DESIGN Final Design 19 December 7 2010 SKY VISION FINAL DESIGN Stabilization System Design Overview The goal of the stabilization system 1s to provide platform stabilization in varying wind conditions as dictated by the Requirements Specification The stabilization system consists of two propellers driven by high rpm electric brushless motors mounted on the same rigid shaft beneath the balloon In order to effectively stabilize against wind the propellers must provide a thrust force equal but opposite to the drag force on the balloon caused by the wind To fully stabilize against the wind the thrust force generated by the propellers must therefore be opposite in direction of the drag induced by the wind In order to align the thrust force opposite to the drag force the propeller assemblies must be capable of 360 horizontal rotation To accomplish the necessary rotation a light weight alignment plate will be attached perpendicular to the shaft supporting the motors The drag force on the alignment plate will cause a moment which will rotate the propellers to the posi
62. er supplies The first 1s a 9 volt battery powering the camera and the second 1s a 12 volt power supply powering the receiver The tan boxes represent connectors and converters The first is a coaxial connector fastening the battery to the camera The second is called a video and audio grabber it takes the auxiliary output from the receiver and converts it to a USB that can be plugged into a laptop 45 December 7 2010 SKY VISION FINAL DESIGN Camera Selection The specific camera chosen 1s provided by boostervision com see Appendix K The criteria for camera selection consisted of factors of weight size image quality wireless range price and availability The following decision matrix demonstrates the justification for choosing the 2 4GHz BoosterVision GearCam Table 3 Decision matrix for camera selection Category Weight BoosterVision Pencil Eraser Cam Zoom Cam GearCam DVR Price 0 4 4 2 1 3 Weight 0 2 5 5 2 4 Wireless Range 0 2 5 3 1 1 Video Ouality 0 2 3 3 4 5 Totals 1 4 2 3 1 8 3 2 The features include a small size and light weight 2 4 GHz wireless mini color camera The camera also includes audio from a built in microphone However the audio feature will not be utilized by the system The device has low power consumption and needs only a 9 volt battery for power The size is 20 mm W by 20mm H by 20mm D These dimensions are equivalent to the size of a dime which makes the device small enough to be suitable for the
63. erson may operate a moored balloon unless it has a device that will automatically and rapidly deflate the balloon if 1t escapes from its moorings If the device does not function properly the operator shall immediately notify the nearest ATC facility of the location and time of the escape and the estimated flight path of the balloon 104 December 7 2010 SKY VISION FINAL DESIGN Appendix B Propeller Justification MATLAB Code 105 December 7 2010 SKY VISION FINAL DESIGN o 5 Balloon pitch deflection syms T p real Ft 11 995 Thrust Toreo Trom propulsion unite IN Fd 12 Wind force N w 5 9 81 system weight N Fb 6 9 81 Bouyant force N oe Sum of forces in x direction sum of forces in y direction egl Ft Fd T sqrt i pal eq2 Fo w Deene 972 oe S solve eql eqg2 T p Tension vpa S T 4 slope vpa S p 4 oe 2f N double Tension 2f degrees double 90 atand slope disp sprintf Tension disp sprintf Tilt Y Y CO CO oe dispisprintr Thr ust 58 21 N double Ft disp sprintf Wind Force 8 2f N double Fd disp sprintf System Weight 8 2f N double w disp sprintf Bouyant Force 8 2f N double Fb disp disp phai 90 atauc slope o ricing force ID w Tension cos phi LLILLLDO 10106 106 December 7 2010 SKY VISION FINAL DESIGN Appendix C Maximum Wind Force MATLAB Code
64. g BUIAI SYLIEY PLL FASTEN OLOFE u amp isac Buuayja SEI emus OLOZIEL OL ubisac wopejd PLL EM OLOZ ZL OL UISJS S EJSLUB7 ufirsar uongaiunuiuio PL oz OLOZ EHOL uBisaq volsinda4g 0 qe mom seme ot fs un TE pol emu 0LOZ LG uomneagiaade syuawannbay pel Olde UG OLOZ EZ 8 a Pel OLOZ G ZL oLOZ Ec g yuawa euep palid uoeing TESTE PES BWEN NSE ot 20g LO N poe HO aioe dag E 0107 Te UE pueg C 8 Col CA d 90 December 7 2010 SKY VISION FINAL DESIGN Fall 2010 Work Breakdown Schedule INN E ee days Management correctly and on time task completion Dec 9 F 2 0 Documentation Ensure changes and progress Engineering notebooks A3 Aug 23 Ph P ed ne aa reports and design reports Dec 9 J C F 3 0 Project Choice Decide on which problem Problem specification report Aug 23 Ph P F4 0 Requirements Complete set of all system Requirements specification Sept 7 Ph P F 5 0 System Design Report of semester goals and System Design and Project Plan 9 8 Ph P amp Project Plan deadlines along with final report Ie functional descriptions of subsystems 3 F6 0 Device Design Complete design of Component selection and subsystems performance specifications of subsystems F6 1 Platform Design of balloon and Type of balloon performance Design mounting infrastructure specifications of balloon design of mou
65. ge spikes below Vss at the MCLR VPP pin inducing currents greater than 80 mA may cause latch up Thus a series resistor of 50 1000 should be used when applying a low level to the MCLR VPP pin rather than pulling this pin directly to Vss 2 Maximum allowable current is a function of device maximum power dissipation See Table 24 6 tNOTICE Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device This is a stress rating only and functional operation of the device at those or any other conditions above those indicated in the operation listings of this specification is not implied Exposure to maximum rating conditions for extended periods may affect device reliability 140 December 7 2010 SKY VISION FINAL DESIGN Appendix O Schmart Board 141 Products Part 202 0011 01 Schmartboard com m LS P 1 ZA LG amp Je P Fa ge N r 202 0011 01 QFP 32 100 Pins 0 5mm Pitch 2 X 2 Grid EZ Version Support up to 100 pins QFP TOFP PQFP package IC with 0 5mm pitch 20 pcs of 0603 package and some thru hole passive components 6 ground holes are connected a copper plane on the bottom side This product utilizes the EZ technology to assure fast easy and flawless hand soldering 142 December 7 2010 SKY VISION FINAL DESIGN Appendix P Voltage Regulators 143 December 7 2010 SKY VISION FINAL DESIGN Figure 8 Fixed O
66. generic H Bridge circuit is shown below in Figure 64 79 December 7 2010 SKY VISION FINAL DESIGN H Bridge Figure 64 Generic H Bridge circuit The reason an H Bridge is attractive for component control is that it allows for the propellers and imaging motors to be turned in either direction based on the state of the H Bridge The control system for this application will need four of H Bridge circuits as four motors are on the system Two H Bridge circuits will send power to the propeller motors and two will send power to the camera rotation motors The following truth table demonstrates the result of various switch configurations A warning must be made against ever closing S1 and 53 simultaneously see Figure 64 for labeling of S1 and 53 since this results in a complete short of the power supply to ground Table 8 Truth table Result motor moves right 1 switch closed motor moves left O switch open motor runs free slows to stop x doesn t matter motor brakes motor brakes not allowed short circuit not allowed short circuit The following diagram shows an H bridge that 1s designed to handle 10 A This feature is crucial to our project because the propellers must be able to provide adequate thrust against the wind In order to provide this thrust adequate power must be provided to the motors driving the propellers In order to deliver adequate power the control circuitry must be able to handle 10 A of current
67. gr 45 o B 4 x 35 S 3 25 o O 2 E 1 5 gt 1 c X 05 0 0 10 15 20 25 30 35 40 45 50 Torque oz in Figure 25 Elevation rotation torque Using the above Figure a servomotor was found which provided an output torque sufficient to generate a high angular acceleration higher angular acceleration equates to faster user response time and thus increases 1mage stability The servomotor selected was a Hitec HS 81 Standard Micro RC Servomotor see Appendix H for data sheet Azimuth Rotation Motor Design The next step in the design of the mechanical portion of the imaging system is the design of the azimuth rotation motor The inertia that the azimuth rotation motor is required to rotate only differs by the inertia added by the elevation rotation servomotor which is very small due to the small dimensions and mass of the servomotor because the elevation rotation motor will be 41 December 7 2010 SKY VISION FINAL DESIGN connected directly onto the output shaft of the azimuth rotation motor The additional inertia contributed by the elevation rotation servomotor is Iservo Mera d 1 79 10 5 kg m Eq 25 where the mass of the servomotor is denoted by Mger o and the dimensions relative to the inertia are 30 mm and d 20 mm Since the torque generated by the elevation rotation servomotor far exceeded the maximum see discussion following Figure 25 and the load on the azim
68. gt Gipe Paul Wind Power Renewable Energy for Home Farm and Business 1 Edition Chelsea Green Publishing Company Y A Cengel Cimbala Fluid Mechanics A Practical Approach Third Edition McGraw Hill 98 December 7 2010 SKY VISION FINAL DESIGN Appendices 99 December 7 2010 SKY VISION FINAL DESIGN Appendix A FAA Regulations 100 December 7 2010 SKY VISION FINAL DESIGN Subpart A General 101 1 Applicability a This part prescribes rules governing the operation in the United States of the following 1 Except as provided for in 101 7 any balloon that is moored to the surface of the earth or an object thereon and that has a diameter of more than 6 feet or a gas capacity of more than 115 cubic feet 2 Except as provided for in 101 7 any kite that weighs more than 5 pounds and 1s intended to be flown at the end of a rope or cable 3 Any unmanned rocket except 1 Aerial firework displays and 11 Model rockets a Using not more than four ounces of propellant b Using a slow burning propellant c Made of paper wood or breakable plastic containing no substantial metal parts and weighing not more than 16 ounces including the propellant and d Operated in a manner that does not create a hazard to persons property or other aircraft 4 Except as provided for in 101 7 any unmanned free balloon that 1 Carries a payload package that weighs more than four pounds and has a
69. gths and Windings Please refer data the data tables to find the right motor for your application Motor 420 8 A20 M A20 L Motor Leistungsbereich max 100W 13sec max 150W 13sec max 200W 15sec Powerrange E Segler bis 500g up to 19oz bis 800g up to 28oz bis 1100g up to 39oz Electric Sailplane er I bis 250g 8 80z bis 550g 190z Helicopter Leerlaufstrom Io 8 4V 0 75A 04A 07A 06A 085A 0 75A Idle Current Io 85 4 V A A CET ET Ry 0 147 0 117 0174 0 10 0 089 Resistance Ri Ohm 28 mm 1 1 Diameter D1 L nge LI 30mm 1 157 34mm 1 33 Length 1 1 Befestigungsl cher l mm 19mm 4 x M3 Mountingscrew diam Iyp Lai Wel Lu 14 Poliger Aussenl ufer Type Drehzahlsteller 4 7 mp Brushless 12 20 Amp Brushless 20 30 Amp Brushless Speed Control Schaltfrequenz 8 16 kHz Switching Frequency A20 S with inbuilt Propsaver 4 C5 P woe J A20 Zubeh r beiligend A20 Items included A20 S mit inte Propsaver 113 December 7 2010 SKY VISION FINAL DESIGN 20 20L Leichter und leistungsstarker Motor f r 3D Modelle bis ca 550g und 3S Setup Lightweight Motor for 3D Airplanes up to 190z for 35 Setup Prop 10x47 APC Slow 10x6 ACC LiPo 3S 3S Volt 10 5 V 10 5 V Amp 17 1 A 14 5 A RPM 7221 8408 Power 180W 153W Contr X 20 X 20 Windungszani Leerlaufstrom Io 8 4V 3 Idle Current Io 28 4 V AJ i AA a Innenwiderstand Fi Oh
70. h 55150000 0 Figure 35 Stress analysis of the PVC pipe URES m 7 1616 003 6 565e 003 5 365e 003 5 371e 003 4 774e 003 4 178e 003 3 581e 003 2 984e 003 2 387e 003 1 730e 003 1 194e 003 5 365e 004 1 000e 033 Figure 36 Deflection of the pipe from the 10 N force The actual attachment of the motor and propeller combination to the PVC is accomplished using bolts There is a bracket attached to the back of the motor see Appendix E for Hacker A20 20L motor which then can be attached with four screws onto an aluminum circle cut out Two bolts will hold the aluminum to the PVC The attachment 1s shown in Figures 37 and 38 54 December 7 2010 SKY VISION FINAL DESIGN Figure 37 Propeller and Motor attachment to the PVC Figure 38 Attachment of stabilization system The bottom of the balloon has four connections for a payload attachment these attachments are a feature of the balloon purchased The four attachments are shown in Figure 39 The mounting rings will be connected onto the balloon infrastructure via a rigid attachment 55 December 7 2010 SKY VISION FINAL DESIGN Figure 39 Infrastructure attachment to balloon The camera will be attached to a system of two motors The first motor will be bolted to the PVC with two screws The second motor will be attached with a bracket to the first motor and the camera itself will be glued to the rotating arm attached to t
71. he addition of thrust force decreases the cable tilt from a large value to a much smaller value and also decreases the tension in the cable to a lesser value thus justifying the use of a dedicated stabilization system Wind Force Calculation In order to determine the necessary thrust force to stabilize against wind the drag force caused by the wind must be quantified The Requirements Specification document dictates that the system must be capable of providing a stabilized image in wind speeds up to 5 m s Drag force is caused by fluid flow external to the body over which the fluid is flowing Assuming that 23 December 7 2010 SKY VISION FINAL DESIGN the flow over the body can be modeled as incompressible accurate assumption since the free stream fluid velocity 1s very low the drag force can be quantified by the following expression Fp gt CppV A Eg 6 The coefficient of drag is Cp the density of the free stream is p the velocity of the free stream is V and the projected frontal area of the body 1s A The projected frontal area of a spherical body is A SON where the diameter of the body 1s D The drag coefficient for a spherical body depends on the Reynolds number of the fluid flow and can only be determined empirically The Reynolds number for external flow over a spherical body 1s Re Eq 7 where v 1s the kinematic viscosity of the fluid flow The critical Reynolds number for the flow 1s approximately 2
72. he second motor s output shaft The 9 V battery will be attached via a battery case for the purpose of changing the battery once the battery loses charge These connections are shown in Figure 40 Azimuth rotation Elevation rotation 9 V battery servomotor servomotor Camera Figure 40 Attachment of camera and 9 V battery to the second motor There are also five lithium polymer batteries that will be attached to the PVC infrastructure Each battery will be placed into a metal case to fit the battery The case will be screwed into the PVC this 1s shown in Figures 41 and 42 56 December 7 2010 SKY VISION FINAL DESIGN Figure 41 Placement of five lithium polymer batteries Figure 42 Another view of the placement of the batteries The entire system design of the platform infrastructure 1s shown in Figures 43 44 and 45 These figures show where the placements of the components are going to be Also the symmetry of the design is evident symmetry 1s beneficial as it keeps the center of gravity along the center of the balloon Figure 43 Attachment of major subsystems 57 December 7 2010 SKY VISION FINAL DESIGN Figure 44 Bottom view of the infrastructure design Figure 45 Comparison between platform infrastructure and balloon dimensions 58 December 7 2010 SKY VISION FINAL DESIGN Tethering Design Overview The purpose of the tethering system 1s to secure the system
73. it length are undesirable as they introduce transmitted power loss through conversion of electrical energy to thermal energy 68 December 7 2010 SKY VISION FINAL DESIGN The last criteria influencing wiring selection 1s the weight of the wire A lower gage of wire 1s much heavier than a higher gage due to the increased diameter of the wire It 1s therefore beneficial for the sake of weight to select the wire which meets a large current requirement without far exceeding the necessary gage The current requirement for the wire gage was set at a value exceeding the maximum burst current from the lithium polymer batteries supplying power to the stabilization system The maximum current draw of each propeller motor is specified by the manufacturer to be 15 A continuous current though the projected maximum draw of the propeller motors in this application 1s 12 A to generate 5 N of thrust per motor Since the power supply of batteries 1s in parallel the maximum current through the wire 1s 30A From the American Wire Gage Table a wire gage of 7 will be selected The maximum power transmission current of 7 gage wire is 30 A the internal resistance 1s 1 634 ohms km and the wire diameter 1s 3 7 mm 69 December 7 2010 SKY VISION FINAL DESIGN Communication System Design Overview The purpose of the communication system is to maneuver the balloon and camera positioning according to user inputs from the ground The communication pro
74. jected frontal area 31 December 7 2010 SKY VISION FINAL DESIGN From Figure 14 the projected frontal area as a function of is Ap DL cos 6 Eq 10 The absolute value of the cosine of 0 1s necessary because the projected frontal area 1s always a positive quantity The initial equation of motion EOM obtained by summing the moments about the center of gravity was mR m D m r2 6 0 5C V2 DL cos0 cos Or 0 Eq 11 5 12 P D wind where m is the mass of the plate and m is the mass of the balloon Two stability points are gleaned from the above EOM 0 90 and 0 270 The first stability point 90 is stable because small displacements from this point do not induce large deviations from 90 The second stability point though 1s only marginally stable since small disturbances from 270 cause large deviations from the stability point It is immediately evident from Equation 11 that there was no term Since there was no term the damping coefficient is zero and the response will not decay to the desired stability point of 90 The model initially developed and presented above was therefore inadequate as a term inducing decay towards stability 1s not present The damping in the system arises because of relative velocity between the alignment plate and the surrounding air The velocity of the air on the back of the plate causes a drag force which is proportional to the rotational rate 6 of the syste
75. l only be capable of letting out 36 6 meters of cable The tethering material will have a factor of safety against rupture of at least 2 0 Inputs 10 N mechanical reeling force Outputs Change in device elevation from 0 meters to the maximum height of 36 6 meters 17 December 7 2010 SKY VISION FINAL DESIGN Imaging System The imaging system will consist of a small camera mounted onto the balloon The camera will be capable of 90 elevation rotation and 360 of azimuth rotation accomplished via independently controlled motors The live video feed will be transmitted to the ground and made viewable on the user interface The camera will be adjusted to focus at a distance sufficient to accommodate the maximum flight height Inputs Control signal from user interface 9 volt power supply from battery to camera 6 0 V and 500 mA to servomotors Outputs Live video feed displayed on the user interface 90 elevation rotation and 360 of azimuth rotation at 9 52 rad s and 0 3 N m Platform The platform consists of both a helium filled balloon and the required mounting infrastructure The helium filled balloon will provide enough lift to bring the system to the desired elevation and the required mounting infrastructure will support the imaging and stabilization systems Input 5 m of helium gas required to lift system helium gas can lift approximately 1 1 kg m at 20 C and 1 atm Output Desired elevation of the syst
76. l stopwatch device To test image stability 1 minute of continuous video will be recorded with the camera locked onto a single object for the entire 1 minute duration The 1 minute video clip will then be broken into 0 5 second intervals and it will be verified that the locked object did not drift more than 25 of the screen size during each interval To test 360 of azimuth rotation and 90 of elevation rotation the device will be flown indoors and the 360 will be verified by the ability of the camera to capture a full panoramic picture or protractor in case of camera failure and the 90 elevation December 7 2010 SKY VISION FINAL DESIGN rotation measured using a protractor The 360 azimuth rotation will be timed using a commercial stopwatch device to verify the 5 minute rotation duration The device will be flown outdoors to verify camera locking ability An object on the ground will be preselected and the camera should keep the object in the video feed for a duration of 5 minutes To verify the maximum flight height of no less than 36 6 meters the device will be flown and the amount of tethering cable measured using a measuring tape and related appropriately accounting for cable droop due to the weight of the cable to the height of the device This will cause the measured tether cable to be greater than the maximum flight height The appropriate relation for cable droop will be provided following appropriate testing and analysis
77. ller A system or mechanism 1s therefore needed to align the plane of the rotating propeller perpendicular to the direction of the wind Two options were considered to accomplish this task The first option was differential thrust generated by the propellers The differential thrust would be produced in one of two ways The first method would be to cause one propeller to generate more thrust than the other causing a net moment inducing rotation The second method would be to cause the propellers to rotate 1n opposite directions thus generating a couple moment causing rotation of the system The second option to align the system was a wind alignment plate which works in a fashion similar to a weather vane Differential thrust was eliminated as an option for two reasons First and most importantly the alignment process would not be automatic and would have to be controlled by the user The user would need to continuously adapt the differential thrust to compensate for randomly shifting wind velocity a feat which would be much too complex for even the most skilled operator Secondly the differential thrust would need to be controlled electronically thus significantly complicating the control circuitry design The first step in designing the wind alignment plate was generating a free body diagram of the balloon and plate The free body diagram is shown below in Figure 12 The center of gravity and centroid of the balloon are labeled G and C respecti
78. ller chosen is the Exceed RC 2 4GHz Radio Control System This programmable device was thought to be perfect for the system because it 1s typically used for small RC helicopters The low cost of approximately 45 dollars made it financially attractive as well This component will take the user manipulations and transmit them to the system Figure 53 Initial RC controller Features include a six channel transmitter complete set with receiver Controls allow for complete forward backward left right up down and pitch control It uses a rotor head for precision and smooth movements it claims it can display great stability and precision for 3D flight this stability may aid the system greatly with the task locking the camera onto a stationary object on the ground particularly during windy situations The system uses frequency modulation and a frequency of 2 4GHz It is capable of simultaneously controlling three servo motors A main concern is whether it will be possible to control all four motors with the device If only three motors can be controlled at a time then perhaps one of the three signals can be utilized as a switching signal Ifthis signal was set one way then the other two signals could control the propeller motors If the signal were set the other way then the remaining signals could control the camera motion Because the device is programmable it will be possible to modify the signal output to conform to the system needs Another solu
79. m RPM Volt Kv Mountinsescrew d am S Palig 10 Poh 14 Pali Drehrahlsteller 30 40 Amp Brushless Speed Control Schaltfrequenz 8 16 kHz Switching Frequency 3 173 mm 0 123 Shaft Diameter D2 Hacker Motor GmbH Hummler Str 5 D 85416 Niederhummel Phone 49 8761 752 129 Fax 49 8761 754 314 email info hacker motor com 114 December 7 2010 SKY VISION FINAL DESIGN Appendix F Wind Alignment MATLAB Code 115 December 7 2010 mb 2 5 Mass of balloon kg R 1 Radius of balloon m mp 0 1 Mass of plate kg B Uus Moment arm of centroid of drag force D 0 05 vertical height of plate m L 2 Length of plate m vw 5 Wind velocity m s pair 1 204 Density of air kg m 3 Ap D L Projected frontal area E X e 5 o Corresponds DO C d of 2 3 oO U Rectangular rod projected area still D L s Thickness or 12 D 0 59 Corresponds to C d Eas 020 C EE NY AT c Fdr j G2 1 7 2 palr Ap C d z 9 33 t 0 0 1 150 Numerical solution options odeset Using default options for tho 0 017 initial conditions on thdot 0 time th vals odell3 wind alignment fen figure 1 plot time th vals 1 r SKY VISION FINAL DESIGN 2 5 mb Rh 2 LIL2Z mp D 2 b mp v Inertia Drag coefficient thickness is L2 Thickness of L2 D thickness 15 12 Or 2 5 ode solver and th 0 ty th optlonSyc0 02 9 title Wind Stabilit
80. m The drag is demonstrated below in Figure 15 as ceste O 0 0 Fa Vy Fp Vp y Figure 15 System damping 32 December 7 2010 SKY VISION FINAL DESIGN The back wind velocity and back drag on the alignment plate are represented by Fp and Vp respectively The distance to the point of action of both forces 1s r The xyz frame rotates with the system The velocity of the air at the back of the alignment plate 1s then V 0 xF k xri Or Eq 12 The magnitude of the force Fp is therefore 1 2 F gt Pair r ApCp Eq 13 Summing the moments about O yields the following result 2m R m D m r 0 5C4V2maDL cos gl cos Or pawrr 6 64 C 0 Eq 14 The absolute value term on the 0 term compensates for the fact that the direction of the moment caused by F changes when becomes greater then 90 The time response of Equation 14 can be found by solving the equation using the ordinary differential equation solvers in MATLAB The MATLAB code used to solve the EOM 1s provided in Appendix F The time response is given below in Figure 16 Wind Stability Response 100 50 70 50 m deg 30 10 0 20 40 60 80 100 120 Time s Figure 16 Time response of wind alignment plate 33 December 7 2010 SKY VISION FINAL DESIGN The wind alignment plate geometry used to generate Figure 16 is contained in the MATLAB code in Appendix F After adjusting the geometries in the MATLAB code and obser
81. m to fly a small video camera to the altitude necessary to obtain the desired live video feed The camera will transmit the live video feed to a user interface on the ground The system will be stabilized by a lightweight stabilization system The stabilization system will be remote controlled from the user interface on the ground 10 December 7 2010 SKY VISION FINAL DESIGN System Overview The goal of Sky Vision is to provide a cost effective method of aerial surveillance for dynamic situations Sky Vision will consist of a lighter than air aerial platform with stable live video imaging and a stabilization system Since most markets with a need for aerial surveillance also demand high adaptability Sky Vision will measure no more than 1 30 m x 1 04 m x 0 56 m To satisfy the needs of the customer Sky Vision will be capable of providing both 360 of azimuth rotation and 90 of elevation rotation of the imaging system Azimuth rotation is defined as a horizontal rotation in a fixed reference plane in this case the fixed reference plane 1s the plane perpendicular to an axis fixed to the device which passes vertically through the center of gravity of the device when it is in a vertical orientation see Figure 1 Ninety degrees of elevation rotation is defined as a rotation from the previously mentioned fixed plane to a position perpendicular to the plane directed downward The stabilization system will provide stabilization against wind force
82. motors is insignificant when compared to the maximum of 130W drawn by each propeller motor Therefore the best scenario 1s to provide power to the central power system from a source independent of the propulsion motor s power supply Wiring Selection One issue with using large amounts of current is that conventionally available 18 gage wire cannot withstand the current required to drive the stabilization motors A lower gage of wire 1s therefore needed for use in the stabilization system Selecting an appropriate gage for the wiring depends on several factors The first factor 1s the type of wiring desired as the type of wiring dictates how much current the wire gage can withstand before failure The two types of wiring are power transmission wiring and chassis wiring Power transmission wiring is wiring in which open air is allowed to dissipate the heat generated by the wire Chassis wiring however is wiring in which the space is enclosed and the heat 1s not dissipated leading to increased wire temperatures and corresponding increases in internal wire resistance Since the system will be in the air and the wiring external the wire gage should be selected based on the current estimates for power transmission wiring The next criteria influencing wiring selection is the internal resistance of the wire gage Higher gage of wire smaller diameter wiring typically involves higher values of resistance per unit length Large values of resistance per un
83. mum of hour flight time and also a minimum of 30 minutes of live video not necessarily continuous from the camera system The motion of the device and or camera should allow for both 360 of azimuth rotation and 90 of elevation rotation of the camera in order to provide a stabilized image Stabilized no more than 25 displacement within a 0 5 s interval of a screen centered locked object The 360 degrees of azimuth rotation should be accomplished in a 5 minute time interval The camera system will be able to lock on via either user control or automation to some object on the ground and remain fixed on that object until the user acquires a new target object The device will be able to rise to a maximum height of no less than 36 6 meters 120 ft in order to ensure customer s needs for aerial 1maging are met The device should obey all pertinent FAA regulations FAA regulation 101 subparts A and B see Appendix A The communication range of the device should be at least 50 meters The device should be able to withstand maximum winds of no less than 5 m s The device should be no more than 0 43 m 15 cu ft and the dimensions should not exceed 1 30 m x 1 04 m x 0 56 m when deflated in order to fit into the trunk of a standard mid sized car based on stats for 2011 Honda Accord The device development costs should not exceed 1 000 USD Deliverables Parts manual and corresponding budget User manual
84. n the form of thrust calculators In order to validate the thrust calculators two different thrust calculators were used and the same numbers were input into each calculator The results were compared and found to be reasonably close in magnitude they are presented in Figures 8 and 9 below The results obtained from the online calculators seem to be reasonable considering the large pitch and diameter of the blades Prop 10x 4 7 APC SF RPM Thrust 18 Altitude 00 RPM 549171 Thrust at 600 asl 509 91 grams or 18 00 oincesz Calculate Mow EPH werzus Thrust Orange line shou your data point u ea RPH gt Figure 8 Thrust calculator 1 http www gobrushless com testing thrust calculator 2 December 7 2010 SKY VISION FINAL DESIGN Fahrenheit Centigrate inches cm Ambient Temperature 59 15 Prop Diameter 10 254 E eS cm Altitude 600 183 Prop Pitch 47 11 9 u evi minute Barometer Pressure 29 1 985 Prop Static RPM 5500 APC SF 10x4 7 K 14 kp 0 95 Supply Voltage amp Current 12 Prop Type Blades 2 e Click to Calculate ETUE 3 EENG Figure 9 Thrust calculator 2 http adamone rchomepage com calc thrust htm It is clear from Figures 8 and 9 that both the motor rpm and calculated thrust values shown circled are close in magnitude Please note that 18 oz force of thrust 1s equivalent to approximat
85. nd blimp Airplane Blimp Weight 1 0 Complexity Total 12 December 7 2010 SKY VISION FINAL DESIGN Organization and Management Sky Vision s team consists of two electrical engineering students and two mechanical engineering students The project tasks will be distributed between the project members as follows O O O Philip Varney Mech Eng Phil 1s the project manager of Sky Vision and primarily responsible for making sure the subsystem plans are completed integrated and tested on time Phil 1s also responsible for finalizing all required reports and ensuring they are completed on time Phil will also be responsible for the design and implementation of the stabilization system and the camera rotation system Phil will work with Cristina to assist her with any difficulties that arise during the development of her responsibilities Julianne Pettey Elec Eng Julianne is responsible for project financing specifically ensuring the budget 1s under control The purchasing of any system components will be done through her to ensure the budget outline 1s followed Julianne will also be responsible for the design and implementation of the camera system and communication system She will be responsible for integrating all of the electrical subsystems and ensuring they function properly with the mechanical systems Julianne will work with Peng to ensure his tasks are done properly and efficien
86. nting brackets and camera rotation system rotation design Oct 26 Design of camera system to Camera selection and 6 2 1 provide live video feed performance specifications data transmitter and receiver F 6 Design of system to rotate Motor and mounting system 2 2 Rotation Design camera 90 selection performance specifications Stabilization Stabilize rotate and translate Stabilization unit design and Ph 1 Design device selection movement C 2 specifications mounting design performance specifications Power Design Design power system to Battery selection power power device distribution design performance specifications Communication Design system to transmit Communication method Design user inputs outputs to from selected control circuitry device design performance specifications Tether Design Design system to secure Selection of tethering cord device reeling device design performance specifications User Interface Design system to receive User interface control circuitry T N E E D F6 4 F6 6 FT ON SI Design inputs and display live video designed performance feed specifications F7 0 Final system design and Nov 9 Ph P and Analysis subsystems and order parts documentation of parts ordering Dec 7 JG FS 0 The final design of system Final Design Report includes Nov 9 Ph P and subsystems schematics and project model Dec 9 J C e Please note that performanc
87. ntinuous from the imaging system The components of the system requiring power are the brushless motors driving the propellers the servomotors providing mechanical imaging rotation the microprocessor the receiver and the decoder which transforms the user input signal from the receiver to a form useable by the microprocessor The components consuming the largest amount of power are the motors of the stabilization system The servomotors providing the 360 azimuth rotation and 90 elevation rotation of the imaging system consume the next highest amount of power The microprocessor receiver and decoder all consume far less power than either of the previously mentioned components Note that the interface between the power supply and the communication system 1s referenced in the Communication S ystem Design Selection of Power Supply for Propeller Motors The motors driving the propellers of the stabilization system require large amounts of power due to the high rotation rates of the motor output shafts The battery required to provide power to the motors must be capable of meeting the power requirements necessary to generate the required amount of thrust The primary concern in the selection of the power supply for the propeller motors was the need for a battery capable of providing substantial amounts of current in the range of 10 12 A To address this concern two options were available the first option was to utilize a conventional bat
88. o 70 30 to 70 30 to 70 56 89 Class 5 S S a 5 Lu eg ss Der mm es 141 75 es mo 81818 0224075 0224100 gt g To order Specify part number durometer color and quantity Standard colors are black gray or royal blue Special colors quoted upon request Dimensional variations are available by special order Durometer tolerance 5 units Factory direct purchases subject to 100 USA dollar minimum per color per durometer and per class 128 December 7 2010 SKY VISION FINAL DESIGN Appendix J 1 Hitec HS 81 Attachment Kit 129 December 7 2010 SKY VISION FINAL DESIGN Hitec Micro Horn amp Hardware Set for HS60 80 81 85 101 RC Servo 56327 This 1s a Hitec micro servo horn amp hardware set 56327 which will fit Hitec HS60 Hitec HS80 Hitec HS81 Hitec HS85 and Hitec HS101 rc Servos Plastic rubber and brass construction Hitec servo horn set d e 2x black T shaped servo mounts e 2x black rubber dampeners e 2x brass eyelets e 2 x servo mounting screws Phillips head e x white straight horn e Ix white servo wheel e Ix white cross horn D Technical Data Hitec rc servo horn set 56327 Fits Hitec servos HS60 HS80 HS81 HS85 HS101 Length of straight arm 29 0mm 1 14 Overall length of cross arm 23 0mm 91 Diameter of wheel 17 0mm 67 Inside diameter of spline 6 0mm 24 130 December 7 2010 SKY VISION FINAL DESIGN
89. or control circuit and camera control circuit which sends power to the stabilization units and camera 5 V and 25 mA control signal to stabilization system and imaging rotation motors 16 December 7 2010 SKY VISION FINAL DESIGN Power System The power system provides the necessary power for the stabilization system user interface and communication system power for camera 1s described under Imaging System The power system consists of a system of four lithium polymer batteries 2500 mAh 11 1 V two voltage regulators and an 11 1 V 850 mAh secondary battery The power system will provide power to the system for a minimum of one hour including 30 minutes of power to the imaging system and a variable amount of power to the stabilization system as dictated by imaging position needs and wind speed Input Power of batteries 11 1 V 2500 mAh and 850 mAh Output Power to systems Maximum of 120 W to each Hacker A20 20L propeller motor 5 V and 45 mA to microprocessor receiver and decoder and 6 0 V and 0 5 A to imaging rotation servomotors Tethering System The tethering system includes both a reel device to allow for ascending and descending of the balloon and also a tethering cable which 1s capable of securing the balloon The device should be deployable to and from its maximum height of 36 6 meters within 10 minutes In order to ensure that the height of the device does not exceed 36 6 meters the tethering system wil
90. orming a dynamic analysis of a spherical balloon immersed in air it was evident that the amount of mass the balloon could lift was proportional to the difference in density between the air Pair and the lifting gas pig with the proportionality factor being the volume of the displaced air Msys V Pair Pig Eq 27 Figure 29 shows a comparison of the densities of hydrogen helium and air over a wide temperature range When the density of hydrogen and helium were compared to the density of air shown in Figure 29 there was only a slight difference therefore for the same volume balloon hydrogen and helium can lift almost the same mass refer to this quantity as static lift potential Figure 30 demonstrates the static lift potential for a spherical balloon with a one meter radius Itis clear from the figure that the lift potential of both gases is very similar 48 December 7 2010 SKY VISION FINAL DESIGN Densities of Useful Gases 1 atm Air m Helium A Hydrogen Temperature C Figure 29 Densities of air helium and hydrogen at 1 atm Static Lift Potential Helium gt Hydrogen Static Lift Potential kg m 3 40 30 20 10 0 10 20 30 40 Temperature C Figure 30 Static lift potential of helium and hydrogen Hydrogen 1s a highly inflammable gas the presence of which creates substantial hazards when working with it Helium however continues to increase in price for unknown reason
91. outlines this decision process Microchip Decision Matrix DSPICSOF6015 68HC12 DSPIC2A4F Programmer Availability 5 B 5 Interteam Colaboration f Motor Control Functionality 5 Free Sample Availability 5 5 2 Past Experience Figure 61 Microprocessor decision matrix The final goal 1s that the microprocessor will have two main functions Both functions will be a direct result of user inputs onto the handheld transmitter device The first function will control the output sent to the stabilization motors The signal sent to the stabilization motors will be a pulse width modulated signal This signal will be sent to a power MOSFET to allow current 71 December 7 2010 SKY VISION FINAL DESIGN to flow to the stabilization servo motors Different duty cycles will be selected to allow high medium or low power supply levels to be sent to these motors The level to be sent to the motor will be determined by the user based on the amount of wind drag on the balloon The second function will be to control the direction the camera 1s pointing These outputs will be sent into an H bridge to allow for changes in the direction of camera rotation The microprocessor will be programmed using the PIC programmer owned by the Harding Engineering Department It will be mounted on a Schmart board prototyping board see Appendix O for ease in interfacing with the other communication components A flow chart describing the operation of the microp
92. pager band 902 928MHz modules are more expensive due to the more complex filtering and modulation required for link reliability at these higher frequencies The option of 2 4GHz was immediately ruled out due to the risk of camera 72 December 7 2010 SKY VISION FINAL DESIGN interference Based on the website recommendations the 418MHz version of the transmitter was selected Figure 54 Transmitter The MS Long Range Handheld transmitter is ideal for general purpose remote control and command applications that require longer transmission distances It will be configured with 8 buttons to meet Sky Vision control needs It contains an on board MS Series encoder This encoder enhances ease of use and security and allows instant creation of up to 2 unique addresses without cumbersome dip switches When paired with a MS Series decoder transmitter identity can be determined and button functions can be established The unit 1s powered by a single 3V CR2032 lithium button cell The below diagram illustrates the internal wiring and organization of the handheld device vcc 8 B 7 6 5 H 3 1 SEL BAUD GND 9 SEL BAUD HS GND GND 4 GND GND KEY INMS5 CND TX CNTL 283233239 451114111 ARRRRAR 1 DATA OUT SEND pm MODE IND CREATE ADOR 3 LICAL ENC MSHS vec T Di AZy m A o Ri B 100k v V GND R4 RIE RT R3 R9 R1
93. peller Protection Casing Design In order to protect both the integrity of the balloon and also the user from the rotating propeller blades the propellers will each be surrounded by a cylindrical duct with wire mesh secured to the front and rear of the cylindrical duct The diameter of the duct will be 12 0 305 m which 1s slightly larger than the diameter of the propellers 36 December 7 2010 SKY VISION FINAL DESIGN Mechanical Imaging Design Overview The mechanical imaging system is responsible for two tasks providing the 360 of azimuth rotation of the camera and also the 90 of elevation rotation of the camera Azimuth rotation or panning rotation is defined as rotation about an axis which is perpendicular to the ground horizontal plane Elevation rotation 1s defined as rotation of the camera from a position parallel to the ground to a position perpendicular to the ground and directed downwards These rotations are better understood visually and as such are presented below in Figure 20 Independent control of these two rotation angles will allow for the camera to essentially have a half sphere of visibility beneath the balloon Balloon Balloon Axis parallel e to ground Moses Elevation rotation 2 rotation plane Figure 20 Azimuth and elevation rotation The independent azimuth and elevation rotations satisfy the following requirement from the Requirements Specification The motion of the device an
94. polymer battery will be capable of providing power for the required 30 minutes of run time The battery selected is shown below in Figure 49 TANIC FIEF ERMASMTI KATTENI 1 ice Figure 49 11 1 V 830 mAh 35 lithium polymer battery The mass of the battery 1s 63 g and the dimensions are 36 x 53 x 21 mm The cost of the battery is 10 00 66 December 7 2010 SKY VISION FINAL DESIGN Power Supply Schematics The advantage of wiring batteries in parallel is an increase in the A h capacity of the batteries while preserving the same voltage of just one of the batteries Since the motors require 11 1 V and a high battery capacity 1t 1s judicious to wire the batteries providing power to the stabilization system in parallel Another advantage of wiring the batteries in parallel 1s that it removes the possibility of one propeller motor running out of power before the other propeller this situation would cause a net moment about the system s center of gravity causing unwanted azimuth rotation of the system The output of 11 1 V will be connected to the power supply of the propeller motor s control circuits Note that that the central power system refers to the power supply of the microprocessor decoder receiver and imaging rotation servomotors J1 t 11 1 V propeller motors Key A 1 V1 _1 V3_1 V5 1 V8 11 1 V 11 1 V 11 1V 11 1 V T T T T Figure 50 Schematic of four 11 1 V 2 5 Ah batteries
95. power consumption limits lt 200 W was an APC SF 10 x 4 7 propeller blade 10 x 4 1 25 4 cm x 11 94 cm corresponds to diameter x pitch To provide the thrust the motor driving the propeller would need to be supplied approximately 130 W of power and would also need to rotate at approximately 5500 rpm Figure 10 below shows the APC SF 10 x 4 7 propeller blade see Appendix D for more information 28 December 7 2010 SKY VISION FINAL DESIGN Wh ay APG SLOW FLYER Figure 10 APC SF 10 x 4 7 propeller blade The next step was to select an appropriate motor to drive the propeller blade at the necessary angular speed In order to achieve high values of rpm and stay within reasonable power supply limits a brushless dc motor was chosen instead of a brushed motor even though the brushed motors often have substantially lower costs An important factor to consider in selecting the motor was a KV value high enough to allow the high rotation rates The KV value of an electric motor is a measure of how many rpm the motor can rotate per volt supplied Another important factor influencing motor selection was the weight of the motor Since the balloon can only lift a specified weight 1t 1s crucial that the weights of all the components be minimized The last factor influencing motor selection was power demands In order to produce at least 5 N of thrust per propeller motor assembly each motor must be capable of receiving at least 130 W of po
96. r PHe 4 or Msys lt 3 mr Pair Pue Eq 29 The mass of the system Msys is all the components included on the infrastructure underneath the balloon The balloon selected is 2 13 m in diameter 7 ft see Appendix L In order to reduce complexity and weight the balloon will be designed to be lighter than air rise on its own rather than neutrally buoyant buoyant force equal to system weight this will eliminate the need for the propulsion system to lift the balloon thus eliminating the motor needed to rotate the propellers to the vertical direction Since the weight of the balloon itself 1s approximately 2 3 kg the estimated lifting capability for the balloon is approximately 2 9 kg a massless 1 meter radius helium balloon can lift 4 5 kg The system mass includes the mass of the imaging system stabilization system power system wires material to hold the components shafts to move the camera and propellers etc The mass of the components are summarized in Table 4 52 December 7 2010 SKY VISION FINAL DESIGN Table 4 System component weights Balloon Camera Camera O The combined mass of the system 1s therefore estimated to be 4275 2 grams Equation 29 estimates a 2 13 m diameter balloon to be capable of lifting 5254 grams since the system mass 1s predicted to be less than this value the system will indeed be lighter than air Attachment Infrastructure Design On the platform infrastructure the two
97. r 7 2010 SKY VISION FINAL DESIGN APPONI OS qe bed don oko on ae E 99 Appendix A FAA Regulations vo esee nens 100 Appendix B Propeller Justification MATLAB Code 105 Appendix C Maximum Wind Force MATLAB Code 107 Appendix D APC 10 x 4 7 Propeller Data Sheet 109 Appendix E Hacker A20 20L Motor Data Sheet 112 Appendix F Wind Alignment MATLAB Code 115 Appendix F 1 Wind Response MATLAB Code 117 Appendix G Elevation Rotation Motor Holding Torque MATLAB Code 120 Appendix H Hitec HS 81 Servomotor Data Sheet 127 Appendix I Transmissibility MATLAB Code 124 Appendix J Sorbothane Vibration Isolation Material sees 126 Appendix J 1 Hitec HS 81 Attachment ku 129 Appendix K Booster Vision Gear am 131 Appendix L Balloon Data Sheet 133 Appendix M Mieropr cessor EE 135 Appendix N Microprocessor Power Demande 139 Appendix O Schmart Board nenne ne ae no di nn bb nn 141 Appendix P Voltage HE e CN 143 Appendix Q Auxiliary to USB Connector ccc cece cece ene e eene 146 Appendix R Remote controller System user ae u a een 148 PCG IK EE Eeer 151 PP PCO T eet 153 December 7 2010 SKY VISION FINAL DESIGN Requirements Specification December 7 2010 SKY VISION FINAL DESIGN Overview The goal of Sky Vision 1s to design and construct a cost effective mobile flight platform with the capability to remotely capture video and transmit the data to a user on the g
98. r response of balloon P 1 J Testing transmit receive signal to user input on the user 2 from to communication interface Verify live video system feed modification recommendations S 5 0 Project Status Statement of project status Project status report Feb 15 Ph P ME E SS LLL S 6 0 System Integrate subsystems to Provides fully integrated Mar 1 0 System Testing Testing of total integrated Complete system prototype 22 and system and corresponding EdodHicadonis modifications BEER to operate system May s J C and system capabilities May 3 Ge 95 SKY VISION FINAL DESIGN December 7 2010 ww o suoneoyppopy pue Bursa uejs s e jou Cw Io I Is 1107 Suds WEISBIQ YAOMJIN 96 December 7 2010 SKY VISION FINAL DESIGN References 977 December 7 2010 SKY VISION FINAL DESIGN A r Altitude Density and Specific Volume Engineering Toolbox Web 25 Nov 2010 lt http www engineeringtoolbox com air altitude density volume d_195 html gt American Wire Gauge Table and AWG Electrical Current Load Limits with Skin Depth Frequencies PowerStream Power Supplies and Chargers for OEMs in a Hurry Web 06 Dec 2010 lt http www powerstream com Wire_Size htm gt Climate Searcy Arkansas Climate Graph Climate United States Monthly Averages Web 25 Nov 2010 lt http www usclimatedata com climate php location US AROS08
99. rmally less than your internal fabrication costs for special work except for the smallest volumes Sheet Stock for Vibration Applications In designing your own vibration mounts from sheet stock keep the following in mind e More is not better A large lightly loaded sheet will have a high spring rate and will not deflect enough to provide good isolation Over compression will lead to short service life The proper compression range is 3 to 20 per cent depending on the Shape Factor Shape factor 1s the ratio of contact surface one side divided by perimeter area See page 11 for calculation of shape factors e Geometry matters Small circular pieces and rings bulge better than squares and rectangles Bulgeability makes for better isolation Use many small discs rather than a few large rectangles for best vibration 1solation performance e Thickness matters The thicker the sheet the lower the natural frequency You need a sheet at least one inch thick to get your natural frequency down to 10 Hertz 10 Hertz 1s your target natural frequency for a 900 RPM motor 127 December 7 2010 SKY VISION FINAL DESIGN e Do not bolt through your Sorbothane sheet The bolt will carry the vibration to the base Use the natural tackiness of Sorbothane or apply adhesives to glue the Sorbothane to metal plates on both sides or consider a custom design with molded in stud mounts e Use vibration rated connections Where bolted connections are used
100. rocessor is shown below in Figure 62 and a pin out diagram of the microprocessor is provided in Figure 63 Set Port E to Input Set Port B to Output i x Yes Create Flags A B C D Initialize all Outputs and Flags to Low Pin EO High No Output Duty Cycle of 296 to Pins BO B1 Yes Di igh in E1 High Output 40 to Pins BO B1 No Output 60 to Pins BO B1 Am es Pin E2 High Output 80 to Pins BO B1 No i p Mes Yes Pin E3 High Turn Camera Up B2 B3 10 Set Flag A High Na Flag A Low Stop Camera Vertical B2 B3 00 Set Flag A Low Yes Turn Camera Down B2 B3 01 Set Flag B High o Yes Yes lt Flag B Low Stop Camera Vertical B2 B3 00 Set Flag B Low Pin ES High E Set Flag C High Yes Turn Camera Right BA B5 10 Stop Camera Horizontal B4 B5 00 gt 15et Flag C Low Turn Camera Left BA B5 01 Set Flag D High Minera Stop Camera Horizontal BA B5 00 Set Flag DLow Figure 62 Microprocessor flow chart 78 December 7 2010 COFSRGISC T T2CKXRC L T3CK RC2 L TACKRC3L TSCK RCA L SCKZCNERGS L SO ZCNSRG7L SDOZCN GRGEL CRU SS2 CNTURGSL U 19 vssL voL NTRA L NTZRA 3L J ANS CNT RBSL Is ANS CNG REAL ANS CNS RES CO AN2 SST VDINICNARB2 CT PGC EMUC JAN UCN RB L PGD EMUDIJANOCNZRBO EH Motor Control ip 4 mb aM aN ANGIOCENRB6 121 H a A e MA a D a B OU ud om kb o MA CSDOIRG13 D ANTIRB
101. round in real time The need for aerial imaging spans a wide array of markets such as search and rescue law enforcement construction the media fire fighting and general recreation Aerial imaging greatly expands the capabilities of the aforementioned markets It reduces the manpower and thus costs and risks needed for many dynamic situations such as monitoring the scene of a crime or surveying the extent of a wildfire In short aerial imaging extends the sensing capabilities of a market from a two dimensional field into a third dimension the sky Currently this capability 1s far too often accomplished through the use of expensive rotary and fixed wing aircraft The costs of the prior options often far eclipse the resources of many markets thus necessitating a cost effective alternative The goal of Sky Vision 1s therefore to create an aerial imaging product which meets both the high performance and low cost requirements of many under resourced markets Problem Statement Obtaining aerial imaging of a dynamic situation can be both costly and complicated There is a need spanning a wide range of markets for an aerial device with the capability of remotely capturing aerial images at a low cost In order to fulfill the market requirements the device should have the capability to be easily transported to the area of interest December 7 2010 SKY VISION FINAL DESIGN Requirements The power system should allow for a mini
102. s Helium was chosen for use as the lifting gas because of the high safety concerns associated with 49 December 7 2010 SKY VISION FINAL DESIGN hydrogen Airgas Company located in Searcy Arkansas provided the best quote on helium at 104 00 per tank plus 0 40 per day of rental for a 220 cubic feet tank Platform Lift Potential mg mass of system x gravity Figure 31 Balloon lift potential diagram Msys 1s the total mass of the system including the mass of the supporting and attachment infrastructure The density of air Pair is proportional to the air temperature and pressure the relationship is provided in Equation 28 The specific air constant K for air is 0 287 kJ kg K The specific air constant for helium is 2 077 kJ kg K The average temperature of Searcy Arkansas in April when the balloon will be tested 1s 20 C US Climate Data It is assumed that since the system operates outdoors then the air pressure 1s the standard air pressure or 101 325 kPa 1 atm It can be inferred from Figure 32 and Equation 28 that the density of air does not significantly change as the temperature varies within reasonable environmental limits 50 December 7 2010 SKY VISION FINAL DESIGN Temperature of the Air vs Density of Air Temperature Celcuis Figure 32 Graph of the density of air compared to the temperature of the air Engineering Toolbox As shown in Figure 33 standard air pressure varies little betw
103. s Additional information will be provided in future revisions of this document as it becomes available For detailed information about the dsPIC3O0F architecture and core refer to the dsPIC30F Family Reference Manual DS70046 Absolute maximum ratings for the dsPIC3OF family are listed below Exposure to these maximum rating conditions for extended periods may affect device reliability Functional operation of the device at these or any other conditions above the parameters indicated in the operation listings of this specification is not implied Absolute Maximum Ratings t Ambient temperature under DIAS eu een ea 40 C to 125 C Storage Temperature ee ee ee 65 C to 150 Voltage on any pin with respect to Vss except VDD and MCLR Note 1 0 3V to VDD 0 3V Voltage on VDD with respect to VSS ee 0 3V to 5 5V Voltage on MCLR with respect to vVee ANEN OV to 13 25V Maximum current out of VSS PiN EE 300 mA Maximum current into VDD pin Note 2 ENEE 250 mA Input clamp current lik Vi lt OOF VIS VDD u a 20 mA Output clamp current lok Vo lt U or VO gt VDD E 20 mA Maximum output current sunk by any I O poim nnne nnn nanne 25 mA Maximum output current sourced by any I O pin essen nenn 25 mA Maximum current sunk by all ports exssiessxosuusuu s ucuntixude iden ee kor an Tolko 200 mA Maximum current sourced by all ports Note 2 nennen nns 200 mA Note 1 Volta
104. se of the tilt and the cable tension T to variations in thrust force and to ensure that the addition of a stabilization system is justified by significant reductions in both tilt and cable tension Large values of tilt in the cable cause large angular deflections of the balloon which contribute to decreased image stability Large tension values decrease the total weight the balloon can lift as the buoyant force has to then counter both the system weight and the tension The values generated by the MATLAB code for tilt versus thrust force and tension versus thrust force are provided in Figures 3 and 4 respectively Tilt vs Thrust Force N o o Ben o0 o o Thrust Force N Figure 3 Tilt vs Thrust Force 22 December 7 2010 SKY VISION FINAL DESIGN Tension vs Thrust Force c 2 u c v gt Thrust Force N Figure 4 Tension vs Thrust Force Figures 3 and 4 were created by holding the wind force constant at 12 N worst case scenario corresponding to wind value exceeding the maximum value specified the system weight constant at 49 N and the buoyant force constant at 59 N and varying the thrust force from Oto 12 N From Figures 3 and 4 it is clear that as thrust force is increased the tilt decreased exponentially and the tension in the cable decreases towards a constant value equal to the difference between the system weight and buoyant force It is evident from the above simulation that t
105. sive twisting of the signal power wires the rotation range of the azimuth rotation motor will be limited to 180 The two motor system 1s shown below in Figure 23 Azimuth rotation motor Motor mounting bracket Camera Elevation rotation motor Figure 23 Motor attachment system Elevation Rotation Motor Design The first step in determining the torque requirement for the 90 elevation rotation servomotor was to determine the inertia of the load on the output shaft of the servomotor A diagram of the system 1s shown below in Figure 24 Servomotor Figure 24 Elevation motor design 40 December 7 2010 SKY VISION FINAL DESIGN The torque of the motor is I and the output shaft attaches to the servomotor at point A The mass of a 9 V battery mj is 45 g and the dimensions are 48 mm x 25 mm x 15 mm and the mass of the camera m is 14 2 g see Appendix K The camera was approximated as a cube with side length of 25 mm Setting L4 equal to 30 mm and L equal to 70 mm yields a total inertia tensor about point A of 7 2 10 13 0 4 10 13 133 9 0 10 kg m Eq 23 0 0 1335 9 Summing the moments about the axis of the output shaft yields following relation where f equals the angular acceleration of the output shaft B 1389 103 T Eq 24 Figure 25 demonstrates the relationship between angular acceleration of the output shaft and the required torque x 10 Elevation Rotation Torque 5
106. small battery weights Due to this the weight of the lithium polymer batteries was smaller than any of the aforementioned options Next the batteries are capable of being easily recharged Also the manufacturer of the propeller motors recommends using an 11 1 V 3 cell lithium polymer battery pack for providing power to the motors The specific battery selected to provide power to the stabilization system 1s an 11 1 V 3 cell 35 lithium polymer battery with a battery capacity of 2 5 A h and a maximum discharge rate of 10 12 C this 1s discussed in relation to the worst case scenario for power requirements and run time in the following pages The mass of each battery 1s 175 g The 35 lithium polymer battery 1s shown below in Figure 47 The dimensions of each battery pack are 58mm x 05mm x 19mm TANIC ais mdep SIR 8 I2 tts ace 11 1 Vest i Figure 47 11 1 V 35 lithium polymer battery The next step in the design of the power supply was to determine the quantity of 11 1 V 3S lithium polymer battery packs needed to provide the correct amount of power to the stabilization system Estimating Required Power of Propeller Motors The power consumed by each motor driving the propellers m order to generate 5 N of thrust each is 130 W see thrust calculators on in Stabilization System Design 5 N of thrust corresponds to the worst case scenario corresponding to the wind speed causing the maximum drag on the balloon wind speed of
107. smitter is a CW Series Whip Antenna The dimensions of this part are shown below 7 8 ER Le 031 0 51 0 13 0 7 01 ll 0 24 178 0 6 0 0 57 14 5 X e gt e End View es 205 gt 025 52 0 Y 0 18 I 4 5 Figure 59 CW Series Whip Antenna This 4 wave antenna delivers good performance in a rugged and attractive package It comes available with standard SMA sub millimeter array connectors or RP SMA reverse polarity SMA connectors It detects a center frequency of 418MHz and is recommended for frequencies in the range of 380 to 450MHz A wide variety of matching connectors make numerous mounting options possible This antenna s output 1s connected to the input on pin 16 of the LR series receiver IC The figure below represents an updated block diagram for the communication system 76 December 7 2010 SKY VISION FINAL DESIGN Pulse Width Modulated Signals to Motor Control Directional Signals to Camera Rotation Motors Encoder Control Buttons Figure 60 Updated communication system Microprocessor Selection The microprocessor selection process was very simple for the project There were a number of convincing factors that led to the final choice of the DSPIC30F6015 The main factors considered were the availability of a programmer the benefit of working together with other teams and the functionality of the microprocessor in regards to motor control The following figure
108. t corner of Figure 5 The regression analysis was very accurate as the squared correlation coefficient R was very close to 1 Entering the regression equation shown in Figure 5 into the MATLAB code in Appendix C yielded the data for maximum wind force vs temperature provided in Table 2 The wind velocity values in Table 2 were selected based upon wind values inducing the maximum drag on the system an explanation 1s provided in the following pages Table 2 Maximum wind force Air Temperature C Max Wind Force N Velocity m s A sample wind force vs wind velocity plot is shown below in Figure 6 for a temperature of 30 C and a 1 m diameter balloon u Abrupt transition Wind Force N due to change in fluid flow from laminar to turbulent Wind Force IN 0 0 5 1 15 2 25 A 3 5 d 45 h Wind Velocity m s Figure 6 Wind Force vs Wind Velocity 25 It is interesting to note that the critical Reynolds number 1s reached at approximately 3 m s This causes the drag coefficient to drop significantly causing the maximum drag force to occur at a velocity between 0 and 5 m s For this reason Table 2 also contains data showing at what velocity the maximum wind force occurs at Evident from Table 2 1s the observation that drag force increases with air temperature From Table 2 it was determined that the stabilization units needed to produce a combined value of at least 10 N to successfully stabilize against wind speeds from 0
109. te at For the sake of generality a dynamic analysis will first be performed and then simplified to the static state by setting all time derivative terms to zero The total angular rotation of the output shaft assuming only elevation rotation 1n the xyz frame is the following 38 December 7 2010 SKY VISION FINAL DESIGN 0 fw n rad s Eq 17 0 In order to obtain the angular momentum the inertia tensor in the xyz frame must be determined The inertia tensor of the output shaft and camera in the xyz frame 1s the following 0 0 0 0 m l ml 0 Uasxyz Ewe c Eq 18 0 0 m 4 mL Since there are two planes of symmetry all of the products of inertia drop out xyz frame is principal set of axes The angular momentum H Io is 1 x Hy Lm ml pj Eq 19 To find the necessary motor torque I the moments must be summed and set equal to the time derivative of the angular momentum Point A is a valid location to sum moments since it is not accelerating no longer acceptable when azimuth rotation is considered YM Mi OH cosw Lm g cos Mzk Eg 21 It can be determined from Figures 21 and 22 that M I Setting the latter two relations equal exposes the fact that M M 0 For the static situation 0 the moment balance degenerates into rT gL cosp Cm me Eg 22 which 1s the static holding torque required by the elevation rotation motor The maximum holding torque occurs
110. tery with a high capacity on the order of approximately 10 12 A h The second option was to use a battery with a high discharge rate Due to concern over the maximum weight of the system it was deemed more feasible to use a battery with a high discharge rate rather than a large capacity Also a battery with a high discharge rate can provide large bursts of current only when large gusts of winds demand it In order to keep operating costs low for the users of Sky Vision the batteries selected to provide power must be rechargeable Several alternatives were examined in order to select the design which best fit the needs presented in the prior discussion The first alternative was to provide power through the 61 December 7 2010 SKY VISION FINAL DESIGN tethering cable and utilize a lead acid battery on the ground to provide the required power However it was found that the weight of 36 3 m of wire of a gage large enough to handle 10 12 A of current was substantially large and far exceeded the lift capabilities of the balloon Also the cost of both the cable and the lead acid battery exceeded the cost of batteries light enough to be mounted on the balloon The next option for power supply was lithium polymer batteries Lithium polymer batteries were selected to provide power to the stabilization system for several primary reasons First lithium polymer batteries have a high energy density they can provide large amounts of power for
111. thdot th 1 is theta itself and th 2 is first derivative of theta phi phi0 1 phidot phiO0 2 phidot phidot phidoubledot c2 cos phi c3 phidot abs phidot 5 Approximate with no damping to obtain max the apli phidot phridogbledot l 119 December 7 2010 SKY VISION FINAL DESIGN Appendix G Elevation Rotation Motor Holding Torque MATLAB Code 120 December 7 2010 SKY VISION FINAL DESIGN oe oe 90 deg Elevation Rotation Motor Holding Torque oe oe oe oe This program calculates the holding torque necessary from the stepper motor providing the 90 degrees of elevation rotation of the camera An L shaped shaft is attached to the motor output shaft and the camera is attached to the end of the L The first portion of the L shaft is shaft 1 the second portion is shaft 2 oe oe oe 3 WO 00 00 o o AC AC AC oo oe oe o9 AC AM 00 oe 9 81 m s 2 c 0 0141 Mass of camera kg ms2 0 01 Mass of shaft 2 kg ped 50 le soU Elevation rotation angle in increment typical of a stepper motor 1 8 deg L2 0 0 005 0 05 Length of shaft 2 m h Lorque g L2 eind 90 40 05 m52 ne 7 Max Veraus 15 when psi S0 plot b2 fi torque title Maximum Holding Torque fontsize 14 xlabel Length of Shaft 2 m ylabel Holding Torque N m o h torque max max h torque Max Holding torque N m 121 December 7 2010 SKY VISION FINAL DES
112. timates of other systems the influencing system design was then edited and those edits were factored into the design of the systems contingent on the edited system For this reason the Network Diagram was changed to add an arrow leaving the System Design and Analysis and into the beginning of the subsystem designs The addition of the recursive element of design caused the estimated times for design to be drastically altered Another primary change was the addition of an Image Stabilization task Image stabilization was a factor in the design of most of the subsystems no one single subsystem existed which cured the problem of image stability Therefore a separate task was added which addressed the problem of image stability as a task inherent to all subsystem designs Also the task of designing the tether cable to transmit power was removed from the Work Breakdown Schedule The schedule analysis for the Spring Semester appears to still remain unchanged as image stability has been designed into all the other subsystems to be built rather than being built as its own physical electrical system Changes to the schedules for the Spring Semester are a reflection of design decision changes ex powering the system via system mounted batteries rather than the tethering cable transmitting power 89 FINAL DESIGN SKY VISION December 7 2010 uiseag Bul PLL OLOZ AL LL LOZIEILL ubisa anog SIS JEU pue uBirsar wasis yeal
113. tion necessary to stabilize against the wind Stabilization System Components The main components of the stabilization system are the following Propellers Electric motors driving the propellers Shaft bracket connecting the propeller motor assemblies to the same shaft High frequency passive not powered vibration damping isolation bolts brackets Wind alignment plate pup Bi Stabilization System Justification In order to justify the use of a dedicated stabilization system a simulation was created and performed which analyzed the dynamics of the system both with the stabilization system and without it The simulation used a free body analysis of the balloon to calculate the tension in the tethering cable and the angular deflection of the balloon about an axis parallel to the ground The first step in the simulation was to develop a dynamic model of the system The model developed is provided below in Figure 2 20 December 7 2010 SKY VISION FINAL DESIGN Figure 2 Dynamic model of system In Figure 2 the center of mass of the simplified system 1s shown to be at the center of the spherical balloon and 1s represented by the designation G The weight of the system 1s designated W the tension in the tethering capable is T the buoyant force exerted on the ys balloon is Fg the drag force is Fp and the thrust force generated by the propellers is Fr The tension in the cable is along the direction of the cable which is
114. tion to having three outputs would be to control both propeller motors using the same signal AlI of the above assumptions made it seem that the communication system was basically designed except for the programming of the device This assumption turned out to be false upon further research First of all upon contacting the manufacturer of the camera it was made clear that some 2 4GHz RC controllers interfere with the 2 4GHz GearCam Upon researching the 71 December 7 2010 SKY VISION FINAL DESIGN non interfering 2 4GHz radios it was discovered that one would cost between three and five hundred dollars Second of all research lead to the realization that the device was designed for a very specific application The tutorials for programming the device made it evident that user manipulation of a single control would cause outputs on multiple receiver channels For the sake of simplicity in programming balloon control it is desirable for each input from the user to affect one output However with the Exceed RC each input will necessarily produce multiple outputs The fact that the device was programmable led to the false conclusion that it could be conveniently modified to fit the needs of Sky Vision Therefore a new control option needed to be chosen for the project Alternative Controller Selection The following decision matrix was formulated after extensive research of available transmitters and receivers The main factors considered
115. tly Peng Yeng Elec Eng Peng is primarily responsible for designing and implementing the power system He will also design the user interface system including controls for both the imaging and stabilization systems Peng will also work with Julianne to make sure her tasks are completed on schedule and also to 13 December 7 2010 SKY VISION FINAL DESIGN assist her in any difficulties which arise during the design and implementation of the camera and communication systems Cristina Belew Mech Eng Cristina is responsible for the design and implementation of the platform balloon and mounting frame and tethering systems She is also responsible for examining any relevant FAA regulations and dictating to the entire team what 1s required to ensure FAA regulations are adhered to Cristina will collaborate with Peng on the mechanical aspect of the user interface design She will also assist Phil in any difficulties encountered during the design and implementation of the stabilization and mechanical imaging systems 14 FINAL DESIGN SKY VISION December 7 2010 S2BjIS u Jes asn oi xnwv Addns Jod AEpuo0Ias Aieneg 1811828Y A 6 sepnjour ZHO v EJSWEN u NEO S PEJ Sc 6 J1010 N 06 u NEO SHEI Sc 6 JOJO 09 yu SZ AS 1n2417 jonu pue 10558201dOI21N ywsz A S ZHNBLF Jaylwsuea L indu ses WEISBIA YOg urojs gS 3910 Buysay N OL wejs s BuUSBUJSL
116. to the ground and also to reel in the platform from the desired elevation The two factors primarily affecting the design of the tethering system are how much the entire system will weigh and also ensuring the system 1s small enough to fit in the 0 425 meters 15 cubic feet requirement The tethering cable must be able to support the stress generated by the balloon pulling upwards and the user reeling the system in It can be assumed that the vertical acceleration of the system 1s negligible since the user can dictate the rate at which the balloon rises by adjusting how much tethering cable 1s released System Components Tethering cable 2 Reeling mechanism and supporting infrastructure Tethering Cable Tension The relation to determine the needed strength of the tethering cable 1s shown in Equation 30 Since the acceleration of the system 1s negligible when the system has reached the desired height the system can be modeled as a static system where the sum of the forces 1s zero The tension T determines the required strength of the tethering cable material T oui pue Enr Msys 9 81 Eq 30 The mass of the system provided in the platform design 1s 4037 2 grams and the radius of the balloon chosen is 1 065 meters Also the density of air is 1 204 kg m and the density of helium is 0 1664 kg m With this equation the tension in the cable is 91 1 N The material selected for the tethering cable is 6 35 mm diameter 0
117. tors with optional saturation logic 17 bit x 17 bit single cycle hardware fractional integer multiplier Single cycle Multiply Accumulate MAC operation 137 December 7 2010 SKY VISION FINAL DESIGN 40 stage Barrel Shifter Dual data fetch Peripheral Features High current sink source I O pins 25 mA 25 mA Optionally pair up 16 bit timers into 32 bit timer modules 3 wire SPITM modules supports 4 Frame modes I2CTM module supports Multi Master Slave mode and 7 bit 10 bit addressing Addressable UART modules with FIFO buffers Motor Control PWM Module Features Complementary or Independent Output modes Edge and Center Aligned modes Multiple duty cycle generators Dedicated time base with 4 modes Programmable output polarity Dead time control for Complementary mode Manual output control Trigger for synchronized A D conversions Quadrature Encoder Interface Module Features Phase A Phase B and Index Pulse input 16 bit up down position counter Count direction status Position Measurement x2 and x4 mode Programmable digital noise filters on inputs Alternate 16 bit Timer Counter mode Interrupt on position counter rollover underflow Analog Features 10 bit 1 Msps Analog to Digital Converter A D A D Conversion available during Sleep and Idle 4 Sample Hold Channels Multiple Conversion Sequencing Options Special Microcontroller Features Enhanced Flash program
118. tted 2 4 GHz video and audio feed It also requires a 12 volt power supply The output 1s the auxiliary 46 December 7 2010 SKY VISION FINAL DESIGN connections A USB video and audio grabber will be needed to convert these auxiliary connections into a format that can be used by the laptop portion of the user interface 47 December 7 2010 SKY VISION FINAL DESIGN Platform Design System Overview The platform design consists of the infrastructure to secure the subsystems to the balloon and the balloon itself The balloon must be a lighter than air system in order to rise on its own without the aid of the stabilization system The main purpose of the balloon 1s to assist the user in getting the camera to the desired elevation specified by the user Some of the factors that helped to determine the size of the balloon included the weights of the components needed on the infrastructure of the balloon and also the amount of helium gas needed in the balloon Helium Gas Design Two potential choices for lifting gas were compared to decide which would be used to raise the balloon hydrogen or helium The principle governing the mass a certain body can lift when immersed in a fluid 1s determined by Archimedes Principle which states that the buoyant force exerted on a body is equal and opposite to the weight of the volume of fluid the body displaces the buoyant force acts through the centroid of the displaced volume of fluid After perf
119. upplied laptop computer will be used to view the live video feed The handheld radio controller utilized by the user to send control signals to the system 1s described in detail in the Communication System Design 82 December 7 2010 SKY VISION FINAL DESIGN Budget 83 December 7 2010 SKY VISION FINAL DESIGN Budget Overview Table 9 Budget overview table Initial Projected Current Projected Spent Stabilization 110 00 107 80 107 80 Imaging System 82 00 124 13 124 13 Main Power Supply 135 00 103 95 73 95 Tether 50 00 19 98 11 50 Platform 350 00 395 90 286 30 Communication 50 00 69 82 69 82 User Interface 48 00 9 00 MicroProcessor and Circuitry 40 00 51 09 51 09 Contingency 135 00 118 33 Percent Spent 78 78 Total 1 000 00 1 000 00 724 59 The initial budget estimate of the stabilization system was a fairly accurate estimate as the difference between the funds spent and funds estimated was only 3 The estimated camera budget was inaccurate because the imaging rotation servomotor costs were not included in the initial budget estimate The power supply was approximately 30 under the initial amount estimated because lithium polymer batteries were found to be cheaper than initially expected The tethering system had a much less cost than that anticipated because the decision was made to power the system using batteries on the balloon rather than sending power through the tethering cabl
120. urrent 370pA 3V Direct serial interface Ultra low 0 1pA standby current e Small SMD package Definable recognition authority Latched or momentary outputs i True serial encoding Encoder ID output by decoder LICAL ENC MS001 MS Series Encoder Applications include LICAL DEC MS001 MS Series Decoder Moyles Entry Door and Gate Openers Remote Device Control Car Alarms Starters Remote Status Monitoring Call Paging Systems 154
121. uth rotation motor only differs slightly Image Stabilization The problem of image stabilization can be broken into two categories image noise due to high frequency vibration and image drift caused by oscillations of the balloon The high frequency vibration of the system 1s caused by the high rate of rotation of the propellers Slight imbalance in the propeller blade can transmit large vibration to the rest of the system Oscillations of the balloon however are caused by displacement of the balloon due to varying periodic random wind force The approach towards solving each of these problems is very different The task of eliminating high frequency vibration 1s simple in comparison to the task of maintaining image stability caused by oscillations of the platform The problem of reducing high frequency vibration transmission can be visualized theoretically by modeling the camera and propeller assemblies motor propeller and protective casing as single degree of freedom DOF masses attached to ground by a joint with stiffness k and damping c The simplified system is shown below in Figure 26 F t x t 1 k C y t Figure 26 Simplified model for camera and propeller assemblies 42 December 7 2010 SKY VISION FINAL DESIGN The propeller assemblies can be modeled as a simple mass which 1s being forced by F t the periodic forcing is caused by a rotating unbalanced mass The frequency of the forcing can be modeled
122. utput Regulator LM7805CT and MC7806 Voltage Regulator Data Sheets Electrical Characteristics MC7805 LM7805 Referto test circuit 0 C Ty 125 C lo 500mA Vi 10V Cj 0 33 F Co 0 1a F unless otherwise specified ee Ge arame ondmons e Tom wc m Output Voltage x Slo x1 SSE SI f to 20V 4 75 Load Regulation Note 1 TJ 25 0C Io 250mA to rv 750mA s Quiescent Curent Pe mem so s9 m Quiescent Current Change TUERI Sata m e Lass om HP mec Output Noise Ta W f 10Hz to 100KHz Ta 25 C f 120Hz VO 8Vto 18V mueve oslo tS E A Short Circuit Current VI SNT 25 C ha m Ripple Rejection 144 December 7 2010 SKY VISION FINAL DESIGN Electrical Characteristics MC7806 Referto test circuit 0 C TJ 125 C lo 500mA V 11V Ciz 0 33acF Cio Q0 1acF unless otherwise specified Parameter SIT Conditions me m mmm Is TJ 25 C Output Voltage 5 0mA lo 104 Po 15W zd UV IO ZIW V 8V to 25V Line Regulation oe ine TJ72 259C ER G 5maAto 1 54 Load Hegulation Nate 1 Hegload 1J 2500 Ilo 25UmaA to SUA L 11 SS SES mese f NN mu EME ERE m ale ha un k na o lo gt 5mA to 1A V aVio 25V Output Voltage Drift AMOIAT necu 5mA Output Noise Voltage VN 0Hz to 100kKHz Ta 2 25 9C T 120Hz V 9Vito 19V ESS EC BEE A N RC R N m o 2 5101 Peak Current T12 250 Uuiescent Current Change
123. vely The drag force on the alignment plate is Fg and is directed in the same direction as the wind velocity V 4 The xyz axis is attached to the alignment plate axis shown in Figure 11 and rotates with the system at 0 The propellers are shown from the side since the alignment plate and the propellers are perpendicular The distance r 1s the moment arm of the drag force about point C 30 December 7 2010 SKY VISION FINAL DESIGN y Wind velocity ann out of page Balloon C G R Propellers side view Figure 13 Wind alignment free body diagram For a preliminary analysis the alignment plate will be designed as a rectangular rod The drag force on the plate Fa is 1 a gt Cp PairVzina Ap Eq 9 where A is the projected frontal area of the plate The coefficient of drag 1s Cp and is dependent on the geometry of the alignment plate Since a fast response is desired the geometry will be chosen to provide a large coefficient of drag The geometry providing the largest drag coefficient 1s a rod with a rectangular cross section with a dimensional ratio of 0 5 cross section height divided by cross section width Cengel and Cimbala 2006 For this geometry the coefficient of drag 1s 2 5 Since the wind velocity direction stays constant and the plate rotates the projected frontal area A of the alignment plate also changes A relation for the changing area was obtained by analyzing Figure 14 Figure 14 Pro
124. ving the results it was found that decreasing the moment arm r of the alignment plate decreased the time till the peak was reached but increased the magnitude of the oscillations about equilibrium A r value of one meter was found to provide the best balance between initial response time till peak and magnitude of oscillation about equilibrium The material used to construct the alignment plate needs to be as light weight as possible for this reason Styrofoam will be used to create the alignment plate Image Stability Stabilization Concerns The effect of the motion of the system particularly the oscillation about equilibrium induced by the wind alignment plate must be addressed In order to gage the effect of the motion on image stability the response time of the 360 azimuth rotation motor of the imaging system see Mechanical Imagine Design must be compared to the angular velocity of the system because these two rotations occur about the same axis The largest angular velocity in the system response was found by plotting the angular velocity of the system versus time using the MATLAB code provided in Appendix F The plot 1s provided below in Figure 17 Wind Stability Response Angular Rate of Change 3 Maximum angular velocity d ardt deg s o 50 100 150 Time s Figure 17 Angular velocity of system 34 December 7 2010 SKY VISION FINAL DESIGN Using MATLAB the maximum angular velocity was found to be 2 81
125. wer The motor selected to meet the above criteria was a Hacker A20 20L Brushless out runner motor The mass of the motor is 55 g 1 94 oz and the motor is capable of receiving 200 W of power at 11 1 V The KV value of the motor is 1022 rpm V at 11 1 V the motor should therefore be more than capable of rotating at 5500 rpm The motor can sustain a constant current of 6 15 A with a maximum burst current of 19 A It 1s interesting to note that the manufacturer of the motor recommends the same propeller blade as was selected earlier in order to prevent motor overload The Hacker A20 20L brushless motor is shown below in Figure 11 see Appendix E for more information and technical specifications Figure 11 Hacker A20 20L brushless motor Wind Alignment Design In order to stabilize against wind the thrust force generated by the propellers must be equal and opposite when compared to the drag force caused by the wind Since the drag force caused by the wind 1s 1n the same direction as the wind velocity the propellers need to be aligned such that the thrust 1s generated in a direction opposite the wind velocity The thrust 29 December 7 2010 SKY VISION FINAL DESIGN force generated by the propellers 1s perpendicular to the plane in which the propeller blade rotates see Figure 12 Direction of thrust force Pd Plane in which propeller LT Zn rotate Figure 12 Direction of thrust force in relation to rotating prope
126. y Response Fontsize 14 xlabel Time s Fontsize 12 ylabel texlabel theta deg Fontsize 12 figure 2 El rth valoia title Wind Stability Response Angular Rate of Change xlabel Time s Fontsize 12 ylabel texlabel d theta dt deg s Fontsize 12 Fontsize 14 function din wind alignment fcn t th0 c c2 Need to provide function with th and thdot th 1 is theta itself and th 2 is first derivative of theta th th0 1 thdot th0 2 thdot s thdot thdoubledot c cosd th abs cosd th c2 thdot abs thdot dth thdot thdoubledot 116 O e December 7 2010 SKY VISION FINAL DESIGN Appendix F 1 Wind Response MATLAB Code 117 December 7 2010 SKY VISION FINAL DESIGN clear L 20 352507 Air temperature C F max zerosi tength I i V max zeros iengthir 1 g 9481 for 1 1 length T pair 1 204 Density of air kg m 3 v 8 79302e 8 T i 1 34039e 5 Kinematic viscosity of air m 2 s V wind 0 0 01 5 Relative wind speed range on balloon m s C d zeros length V wind 1 Drag coefficient R 1 065 Radius of balloon assume spherical m Re V wind 2 R v Reynolds number for flow over a sphere A pi R 2 Projected frontal area of spherical balloon for j 1 length V wind if Re j lt 4e5 Sr 4 x 10S slightly larger than Be or C aj 4 37 a ES for 1 lew Re Re or elseif Re j gt 4e5

Sky Vision: Final Design

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