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Inspect Design Document - MIT Space Systems Laboratory

1. EE EI mimm E RE nO 60 95 ETHERNET x1 Figure 111 Multiple Interface Connector MIC Printed Circuit Board v12 CK CL GP May 15 2014 16 831 SPHERES INSPECT Design Document 147 60 95 SI 5U 1 U ETHERNET Figure 112 Multiple Interface Connector MIC Printed Circuit Board v12 CL May 15 2014 16 831 SPHERES INSPECT Design Document 148 60 95 SI 5U 1 fU ETHERNET X1 Figure 113 Multiple Interface Connector MIC Printed Circuit Board v13 CL GP May 15 2014 16 831 SPHERES INSPECT Design Document 149 BOARD m r M e Caf Caf af efi fi SI 5U1 U ETHERNET Figure 114 Multiple Interface Connector MIC Printed Circuit Board v 14 CL GP Z LL LL ZJI 407F VOLTAGE REG Figure 115 Multiple Interface Connector MIC Printed Circuit Board v17 CK CL GP May 15 2014 16 831 SPHERES INSPECT Design Document 150 13 2 Custom Eagle CAD Parts CK Throughout the design of the MICPCBs several essential parts were found that lacked an Eagle CAD library This required custom Eagle CADs to be made for specific parts that were necessary to route power and data through the MICPCBs Specifically the voltage regulator screw terminal and Ethernet connector on both the tested and integrated MICPCB and the planned health monitoring MICPCB lack accessible Eagle CAD representations The S24SE12002PDFA DC DC voltage re
2. May 15 2014 16 831 SPH RES INSPECT Design Document 110 not exceed 55 5 watts H 2 Establish communication between the Optics Mount and Avionics Stack through Halo The Avionics Stack must be able to recognize the Optics Mount and receive and send data l 1 Record elapsed running time of test on solely battery power while running low frequency BlobTrack test program The system must be able to run the program for at least 30 minutes l 8 Processing of images files from Optics Mount into useful BlobTrack data at a frequency of at least 0 5 Hz constitutes calculations on the order of 0 3 GFLOPs The test program must be able to run at 0 5 Hz 6 2 4 8 Future Testing AL HL 6 2 5 Future testing must involve running a similar test procedure while the INPECT system is mounted on an air carriage If the system is capable of running on an air carriage the testing will proceed to final integration testing of INSPECT with all sensors and the CMG units present connected to the VERTIGO Avionics Stack MICPCB Integration Tests CL CK KAF The integration of the MICPCBs occurs after the successful integration of ORF and ThermoCam with the VERTIGO Avionics Stack and Halo This series of tests is to check the ability of the MICPCB to successfully integrate with Halo and to provide the correct power to the ORF and ThermoCam such that all sensors are powered and able to take data After
3. Verification Verified ThermoCam has maximum blur coefficient at 0 16 System shall be able to translate in a controlled manner through three dimensional space in a Translation is microgravity environment to SX 1 necessary for C 2 Translation 1 cm accuracy SX 2 navigation Testing Verified The design choice to use SPH RES as a platform inherently meets this Verification requirement confirmed by ConOps testing System shall be able to control its attitude through three dimensional space in Attitude control is a microgravity environment SX 1 necessary for C 3 Attitude to 0 5 degree accuracy SX 2 navigation Testing May 15 2014 16 831 SPHERES INSPECT Design Document 20 Verification Unverified RGA testing scheduled for Summer 2014 System shall be capable of achieving an angular velocity below 0 58 rpm in inspection mode and Sensor blur requirements during inspection and SPHERES internal gyroscopes during navigation limit Angular below 9 rpm in navigation SX 1 allowable angular C 4 Velocity mode SX 2 velocity Testing Verified Flat Floor testing confirms precise rotation rates anywhere in the range below 9 Verification rpm Need to know when CMGs are The system shall be able to approaching track saturation levels at all saturation to maintain C 5 Saturation times SX 1 command authority Testing Verification Verified Testing
4. MESA SR4000 4 64 Measured Regulator 0 63 Assuming 85 efficiency Total Spent 5 27 Budget Remaining 4 296 4 1 3 5 The MESA SR 4000 ORF requires 12V to operate within a range of 2 to 41096 or 11 76V to 13 2V 7 Halo provides 11 1V which means that the MICPCB connecting Halo to the ORF requires a voltage regulator to step up the voltage to 12V for powering the ORF Power is routed from Halo through the Samtec 50 pin male connector on the MICPCB The Delta S24SE12002PDFA a DC DC power regulator with 9 36V input 12V output and 20W was used in the MICPCB to step the voltage up to the 12V require by the ORF While the health monitoring system discussed in section 4 1 1 6 was not implemented the ORF was protected from any power surges by the Delta S24SE12002PDFA voltage regulator which was found out to reset the current draw to OA if the current rose above about 1 5A The MICPCB which was integrated with the system to facilitate power delivery from the Halo to the ORF can be seen in Figure 35 The intended next version of the MICPCB with health monitoring system can be seen in Figure 31 CK Data and Interfaces CK As seen in the MICPCB Schematic Figure 36 the ORF connects directly to the MICPCB to share data over Ethernet pins 1 amp 2 and 3 amp 6 The MICPCB then makes a direct connection between the Ethernet data links to the appropriate pins on the Samtec ERM8 025 09 0 S DV K TR male 50 pin connect
5. Step 2 Assembly During this phase the components will be integrated with the SPHERES and Halo subsystems Once all components are set up and turned on the vehicle will be placed in the appropriate starting pose for the selected inspection maneuver Step 3 Inspection During this phase the system will execute the inspection maneuver chosen during the pre mission stage Step 4 Data Recovery During this phase data will be transferred from the VERTIGO avionics box to an off system computer via a physical link Step 5 Disassembly During this phase INSPECT will be disassembled into its component subsystems and repackaged for storage 2 3 2 2 Inspection Maneuver The inspection maneuver carried out by the INSPECT system will consist of two phases A pure translational inspection phase in which no non attitude keeping attitude adjustments are necessary The second phase is a pure rotational inspection phase in which no translational system movements are necessary These maneuvers are optimal when the object of inspection is a landscape compared to one of a single object Basic Procedure 1 Characterize the length of the landscape being inspected 2 Determine the distance away from the target landscape at which inspection shall occur 3 Determine the locations along the path at which images shall be taken 4 Determine the accelerations needed to reach the locations at which images will be taken The constraints put onto the trade stud
6. Electronics 3000 2700 2706 53 0 24 Total Allocated Cost 25500 Total Allocated Cost Less 10 Margin 22950 Total CBE Cost 10994 99 Total Remaining essor 20 4 Subsystem Design 4 1 Payload 4 1 1 Halo on SPHERES JB 4 1 1 1 Driving Requirements and Purpose Relevance to INSPECT JB Halo is designed to support up to six different sensor and actuator peripheral systems including the sensors and actuators used by INSPECT Mechanically it facilitates the physical connection May 15 2014 16 831 SPHERES INSPECT Design Document 41 of up to six peripheral systems surrounding the SPHERES platform while simultaneously leaving open channels for thruster plumes to propel the SPHERES Electrically Halo facilitates connection to the VERTIGO Avionics Stack and internal SPHERES DSP and data routing as well as both regulated and unregulated voltage and current via four on board battery packs Halo enables all INSPECT subsystems to be simultaneously connected to SPHERES and the VERTIGO Avionics Stack and peer to peer to one another via an Ethernet or USB switch For this reason INSPECT requires that Halo have both Ethernet and USB data lines on the Halo ports to support its sensors HP2 Not Visible Main Power lt a Le Ethernet Port d Not Visible HP3 1 Support Sleeve HP 4 Not Visible Figure 30 Halo Overall Layout 5 4 1 1 2 Design Choice JB The specific Halo design choice was made
7. SPHERES but needs further exploration for future multi SPH RES configs Testing subsystem components on VERTIGO C Peripherals interfere with SPH RES ability to communicate with beacons System or testing hardware are emulator and VERTIGO Avionics Stack prior to structurally electrically damaged during integration adherence to pre determined test plans testing and purchase of multiple MICPCBs and board components in case of damage Open communication with Halo team use of Ethernet switch and Optics Mount Ethernet port to provide data Delays in reaching full Halo functionality transfer while Halo data lines are not functional impact INSPECT schedule Construction of testing structures with Halo mechanical interface footprint to mount peripherals to conduct simulations using external power supplies CNG controller board repair for current Open communication with Honeybee and Draper E anomaly in CMG port 2 delays further Labs use of controller board as is when connected to integration external power supply INSPECT schedule software team is experienced with serial communications systems Vibration dampeners have been incorporated into CMG mounting system significantly reducing vibrational effect on other peripherals mem Another iteration of MICPCB design should be carried H dis do S E use cu Ve out to include an LED that reports the status of 9 penp peripheral component Vibrations due to CMGs reduce image accuracy Open communica
8. including the ThermoCam and the ORF as well as route information to the SPHERES from the CMGs 4 1 2 1 2 VERTIGO Optics Mount The VERTIGO Optics Mount acts as the main sensor of VERTIGO acting as physical housing for two stereoscopic cameras It also contains the input ports for VERTIGO one May 15 2014 16 831 SPHERES INSPECT Design Document 51 4 1 2 2 Ethernet and two USB 2 0 ports as well as LED lights for environment lighting Driving Requirements and Relevance to INSPECT AL The driving requirements for including VERTIGO as a payload for INSPECT are listed in Table 8 VERTIGO Driving Requirements These requirements concern the VERTIGO Optics Mount in its capacity as a distinct peripheral sensor system in INSPECT The first three requirements ID prefix SEN define the scope of the Optics Mount sensor while the other requirements ensure that the sensor can interface with the rest of the system Table 8 VERTIGO Driving Requirements All imaging sensors shall Expectation of 30 have a minimum field of degree rotation per view of 33 degrees by 33 SX 1 image sequence with SEN 1 Field of View degrees SX 2 10 overlap Testing The system shall determine the distance to a target object accurate to within 10 Target cm with precision to 2 cm SX 1 SEN 2 Distance up to 10 meters away SX 2 Defines ranging limits Testing The system shall resolve a visible light image of a 1cm Visible Lig
9. kornspan mit edu Krasner James J ikrasner mit edu Krusell Grace gkrusell mit edu Lee Hang Woon hwlee725 mit edu Lira Alessandro alira mit edu Liu Connie cyliu mit edu Mehnert Stadeler Herbert F hmehnert mit edu Miller Nathan millern mit edu Navarro Rebecca H rnavarro mit edu Pantazis George geopant mit edu Santisteban Joel T jtsantis mit edu Sheerin Todd tsheerin mit edu Siu Ho Chit hoseasiu mit edu Venegas Anthony L anthonyv mit edu Vernacchia Matthew T mvernacc mit edu Wagner Travis L tlwagner mit edu Wassenberg Alexandra alewasse mit edu Wenzel John C jcwenzel mit edu May 15 2014 16 831 SPHERES INSPECT Design Document 131 11 Appendix B Subsystem Tradespaces 11 1 Optical Rangefinder MV To reach this decision the type of optical range finding sensor to be used was considered The following Optical Rangefinder types are commonly used in the robotic navigation community and were considered for use in INSPECT Table 43 Rangefinder Technology Comparison Sensor Class Model Typical Typical Scanning Worksin Other considered for Cost Max Structure direct inspect USD Range m sunlight EDAR 2p Mokuyo UFM 3 000 30 2D Yes Laser safety scanning 30LX LIDAR 2D None to scanning multi bx Snie 30 000 30 3D Yes Laser safety beam H E
10. m Power HP3 Board z in out in out HP4 in out NOTE all polyfuses are 1 5A Figure 33 Halo Motherboard Circuitry 5 May 15 2014 16 831 SPHERES INSPECT Design Document 45 Data USB VD6 lines in out VERTIGO 50 pin connector 5V Regulated Figure 34 Halo Port Circuitry 5 Printed Circuit Board JB CK CL GP A printed circuit board PCB acts as an interface between the peripheral subsystem sensors and their respective Halo ports facilitating the appropriate routing of both power and data signals The Multiple Interface Control PCB MICPCB board layout used for integrated testing can be found in Figure 35 This version is a simplified version of the MICPCB shown in Figure 37 MIC PCB with health monitoring system GP CL CK The decision to use the simplified version for testing was made in the interest of streamlining whole system integration rather than devoting time to performing additional testing of the MICPCB health monitoring system The intent is that the MIC PCB with the health monitoring system will be used in further testing and development of INSPECT The MICPCB with health monitoring and without health monitoring have identical essential components including the voltage regulator screw terminal and Ethernet connector which is why testing without the health monitoring system was deemed appropriate for the current INSPECT prototype CK The MICPCB is designed to serve as the P
11. Position Error m ORF On T T T T T T T T T LL 1 1 L 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 1 Figure 45 The distribution of position error samples measured with the ORF operating continously 10 At the nominal INSPECT imaging rate of 1 Hz the ORF operation caused the positioning error of the Metrology system to increase to 140 of its normal level see Figure 46 This error increase is sufficiently low to allow the operation of the ORF in conjunction with the Metrology system in INSPECT May 15 2014 16 831 SPHERES INSPECT Design Document 62 ORF Off 1200 T T T T T T T T T 1000 800 600 400 No of occurences 200 i L 0 4 0 5 0 6 0 7 0 8 0 9 1 Position Error m ORF On 1500 T T T T T T T T 1000 8 No of occurences L 0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 1 Position Error m Figure 46 The distribution of position error samples measured with the ORF powering its lights for approximately 5 ms every 1000 ms 10 Future researchers may wish to reduce the position and attitude determination error induced by the ORF In order to do so it will be necessary to synchronize the operation of the ORF s lights with the Metrology system so that the Metrology system is shut down while the ORF is operation and vice versa Two options are presented for this synchronization a message based architecture and a timer based architecture In both architectures the operation of
12. image sequence with SEN 1 Field of View degrees SX 2 10 overlap Testing The system shall determine the distance to a target object accurate to within 10 Target cm with precision to 2 cm SX 1 SEN 2 Distance up to 10 meters away SX 2 Defines ranging limits Testing The system shall resolve a visible light image of a 1cm Visible Light per pixel resolution from 1 SX 1 Defines optical SEN 3 Image m SX 2 resolution limits Testing All sensors shall send data at a rate which can be processed by the VERTIGO computer or must include its own computer for data SEN 4 Sensor Data processing SX 4 Need to transfer data Testing The system shall resolve a thermal image of a 5x5 cm object from a distance of 1 Defines thermal m to 5 degrees C resolution limits and accuracy and a noise accuracy precision to equivalence temperature produce a reasonable Thermal difference of 1 degree C SX 1 thermal image for our SEN 5 Image at 20 degrees C SX 2 purposes Testing Pose The system shall be able to SX 1 Ability to support guest SEN 6 Sensors determine its pose in 2 SX 2 scientist navigation Testing May 15 2014 16 831 SPHERES INSPECT Design Document 67 dimensional space with 1 SX 5 axis of rotation normal to the test floor necessitates navigational sensors algorithms 4 1 4 2 Design Choice KAF TW 4 1 4 3 The thermographic camera chosen for the INSPECT system is the FLIR A5 micro bolo
13. since INSPECT is designed for testing only inside ISS this limitation will not pose an immediate issue Additionally Phase ToF cameras are limited to a maximum of approximately 20m the SR4000 has a limit around 7m This operational range will also not suffice for SPHERES X As such SPHERES X will not be able to use this class of sensor That being said the MESA SR4000 will output information in the same format as that produced by a LIDAR so when an appropriate rangefinder is procured for SPHERES X the interfaces and data processing methods used by the SR4000 will transfer directly to the rangefinder used by SPHERES X 4 1 8 8 Mounting Structure NC MV Mounts were designed for both the MESA SR4000 and the FLIR A5 The mounts were designed to use the same components so that spare parts could easily be manufactured to fit either one The major considerations that went into the mount design were fitting the required sensors and MICPCBs weight avoiding plume impingement and ease of manufacture For the MESA SR4000 an additional concern of thermal conductivity was considered as the sensor tended to overheat if left on for extended periods of time May 15 2014 16 831 SPHERES INSPECT Design Document 57 To address these concerns the mounts were designed to bring the sensors out of the plume impingement zone of the SPHERES thrusters They were water jetted from aluminum plates with excess aluminum cut out when possible to reduce weight NC
14. 11 December 2008 Online Available http www veracityglobal com media 27197 vwp 16 831 SPHERES INSPECT Design Document 129 21 22 23 24 25 26 May 15 2014 002 20po0e 20explained pdf Accessed 24 November 2013 MIT Space Systems Lab Vertigo Avionics Stack Interface Control Document Cambridge 2012 Littelfuse Inc Data Sheet PTC 1812L Series 2012 Online Available http www littelfuse com data en Data_ Sheets Littelfuse PIC 1812L pdf Accessed 24 November 2013 T M S S Ruel Target Localization from 3D data for On Orbit Autonomous Rendezvous amp Docking Neptec Design Group Ltd Kanata Ont D L Miller MIT Space Systems Laboratory Cambridge MA 2013 D W Miller A White Paper for Exo SPHERES a Retrievable Free Flying Research Platform for ISS 2009 MIT Space Systems Lab UDP PDR Cambridge MA 17 Oct 2013 16 831 SPHERES INSPECT Design Document 130 10 Appendix A Contact Information Name Email Arroyo Flores Krystal D kdarroyo mit edu Byrne James M micbyrne mit edu Chambers Blake W blakejwc mit edu Chander Meera R mchander mit edu Colgan Nathan ncolgan mit edu Edelman Brent D bedelman mit edu Elizalde Jason D elizalde mit edu Jardine Lachlan James ljardine mit edu Hobbs Katherine khobbs mit edu Kaplan Candice ckaplan mit edu Kornspan Melissa L
15. 15 0 05 0 45 0 05 0 30 0 29 S 3 was verified by checking power draw from each of the components the greatest of which was the ORF drawing 13 36 watts which is still below the maximum component draw of 16 65 watts at each port 2 Halo Requirement Checks Halo physical connection was verified via inspection as all components had structural mounts designed to accommodate the 4 hole screw pattern and all were successfully and sturdily attached The data connection was checked via the Ethernet cables which actually had to bypass Halo at this point and connect through an Ethernet switch to the VERTIGO avionics stack as our current Halo prototype does not support data connection This is expected to be resolved May 15 2014 16 831 SPHERES INSPECT Design Document 125 for future tests Power conversions were analyzed and checked via the interface boards to successfully convert voltage and operate safely within the power limit Analysis for H 4 was shown to produce a 79 N force in the Z direction which was compensated for by adding appropriate supports to the mounting structure to support Halo thus decreasing the total force on Halo to less than 10 N This is well below the maximum allowed 40 N force 3 SPHERES X Traceable Requirement Checks Software data alignment was successful and data output was in a format compatible with the standard autonomous SLAM protocols showing SX 2 and SX 5 to be verified Human visible identification
16. 22 31 and 40 98 W the team has designed Printed Circuit Boards PCBs for the ORF ThermoCam and CMGs to interface with their respective Halo ports The Optical Rangefinder for the INSPECT prototype is the Mesa SR4000 selected for its 699 by 569 field of view and ability to meet INSPECT accuracy and precision requirements The Thermographic Camera is a FLIR A5 with a 440 by 369 field of view and the ability to detect temperature differences of less than 1 The CMGs on INSPECT are Honeybee s Low Earth Orbit Control Moment Gyroscopes providing attitude control for navigational maneuvers The INSPECT team is composed of two principal investigators a project manager systems lead chief engineer and the following subsystems Systems Structures ThermoCam ORF CMGs and VERTIGO The INSPECT Hardware Acceptance Review was conducted on April 18 2014 and a preliminary prototype was demonstrated and delivered at the INSPECT Bench Review on May 13 2014 Table of Contents 1 INTRO AUCH ON vc 11 1 1 Mission Statement MC MK 22 556 1 5 ra roe tin cene nn nno cro nn ead eun sero oa de satcdesceeseedtacnedeatieciess 11 1 2 Motivation and Vision MC MK eeeeeee eese eene eene nennen nnne nnn nnn nn trht nens n anon sn tnis 11 1 3 Team Organization MC JB 1 2 21 rete er nonno so hn oorr hn nnn nau rao poe Aa hana RR ERR aaas diass RR Raab KEN 12 2 Mission OVOVICW EREER Em 14 2 1 Context UW WEE 14 2 2
17. 4 In the event that more than 1 5A of current is pulled from any Halo port a PPTC fuse on Halo will trip disconnecting the responsible Halo port from receiving further current until the port is switched off and back on A similar response occurs when greater than 7 5A of total current is pulled from Halo s batteries the entire system will trip a PPTC and will need to be entirely reset by the Halo master power switch This maximum power limit levies an additional constraint on the system by preventing all peripherals from powering up at the same time to avoid tripping the total power fuse This sequential power scheme extends also to individual CMGs requiring that each CMG power on one at a time in order to not trip their own port or the entire system as a whole This is discussed in more detail in Section 4 1 5 4 All peripherals may run simultaneously operating on their average power budgets without concern of exceeding them May 15 2014 16 831 SPHERES INSPECT Design Document 90 4 2 8 Power Requirements The processor power requirements are shown in Table 3 Power Budget Allocation and Table 33 Power Requirements for Avionics Processor Box A 1096 regulator inefficiency has been added as discussed in Dr Brent Tweddle s thesis 6 Table 33 Power Requirements for Avionics Processor Box 6 Components Minimum W Typical W Maximum W Pico ITX P830 10 5 13 17 7 Flash Drives 1 25 1 25 3 4 Miscellaneo
18. Aluminum was chosen over plastic materials despite the slightly harder manufacturing process because aluminum is a better conductor and could be used to conduct heat away from the MESA SR4000 to extend its operating time Figure 41 The CAD model for the sensor mount Holes on the bottom plate allow for installation of the ORF NC 109 14 167 34 Figure 42 ORF Mounting Structure dimensions in mm NC This mount connects to the Halo Port Footprint Figure 31 via the outer set of inboard to outboard male mounting screws which screw into female threaded holes on either the ThermoCam or ORF mount structure rear plate The inner holes are used to secure the MICPCB in place so that the male 50 pin Samtec connector can make a secure connection with the corresponding female 50 pin Samtec connector on Halo To ensure that the mount does not cause any electrical shorts on the MICPCB the face adjacent to the MICPCB is covered in a layer of insulating kapton tape NC May 15 2014 16 831 SPHERES INSPECT Design Document 58 4 1 3 4 Power and Interfaces KH CK JB MV Table 16 Optical Rangefinder Peak Power Budget JB MV Peak Power Budget 16 5W Item Power W Notes MESA SR4000 5 74 Measured Regulator 0 78 Assuming 85 efficiency Total Spent 6 52 Budget Remaining 60 596 Table 17 Optical Rangefinder Average Power Budget JB MV Average Power Budget 5 5W Item Power W Notes
19. Assembly View Wiring Not Pictured JS 36 Figure 27 a and b Integrated INSPECT System Configuration Isometric and top views respectively jp LC 36 Figure 28 INSPECT Integrated Testing Configuration May 2014 rear view 37 Figure 29 INSPECT Integrated Testing Configuration May 2014 front view 37 Figure 30 Halo Overall Layout Il 42 Figure 31 Halo Port Footprint Rotated 90 Clockwise 5 JB 43 Figure 32 Halo Power Board Circuitry 5 enne nennen nnns 44 Figure 33 Halo Motherboard Circuitry Il 45 Figure 34 Halo Port Circuitry T 46 Figure 35 Multiple Interface Connection PCB MIC PCB CL CK GP 47 Figure 36 MIC PCB Testing Schematic CL CK sisi 49 Figure 37 MIC PCB with health monitoring system GP CL CK 50 Figure 38 MIC PCB schematic with health monitoring system GP CL CK 50 Figure 39 VERTIGO Avionics Stack Software Data Flow Diagram sse 54 Figure 40 MESA SR4000 Phase Shift Time of Flight Camera 7 57 Figure 41 The CAD model for the sensor mount Holes on the bottom plate allow for installation of the ORES NG mM Ec 58 Figure 42 ORF Mounting Structure dimensions in mm NC 58 Figure 43 The SPHERES Metrology system uses time of flight measuements from ultrasound beacosn to the SPEI RES Ssat llit 912285 ee an t eee elt eb een b ta ree i texta 60 Figure 44 The highest priority interrupts in the SPHERES DSP
20. C provide sufficient heat dissipation and affect data accuracy Likelihood Figure 81 Thermographic Camera Risk Fever Chart 5 4 CMGs JK Table 40 CMGs Risks and Mitigations A CMG control box e EE Correct interfaces can be procured or machined physically or electrically Power draw from CMGs is too great to sustain B battery power for 30 minutes Analyze potential power saving setups Honeybee Code is not compatible with VERTIGO software environment Develop INSPECT ACDS software from scratch May 15 2014 16 831 SPHERES INSPECT Design Document 99 Likelihood Figure 82 CMGs Risk Fever Chart 5 5 System Level Risks MK The following risks have the potential to impact the ability of INSPECT to meet systems level requirements and or significantly delay further development of the INSPECT system The status of each of the risks below should be tracked throughout the course of the project to assess when and which mitigation plans should be employed Table 41 System Technical Risks and Mitigations Future flat floor testing should place beacons at varying levels to increase chance of signal reaching SPHERES Wiring on INSPECT should be reduced when data lines are functional on Halo ports which will reduce signal blockage Verified ability of ORF to turn off LED and conducted ORF interferes with SPHERES IR metrology preliminary research to synchronize ORF with during future testing with multiple SPHERES
21. ER latine Iu ss 139 12 2 3 Trade Study tet teet tte ee A PA te tnt E 139 12 24 Decision Made orte tne E eae PE e eR dee a vin Hee eene e ER He d de in 139 12 2 5 Incorpotation sn eee Rooster tei laie da alre oec he ee bee Bene eee te beac Coe codon ebrii eoe 140 12 3 Proximity Sensors KH user n e NENNEN ENEE NENNEN EEN de ee 140 12 3 1 Purpose and Relevance to INSPECT iii 140 12 32 Req irements Satisfied cre err e eer en tn ERE NY riens items se 140 12 3 3 Trade Study2s a Re e abet e PB MS 140 12 3 4 Decision Made eerte ettet t rn dee bead oa Oe euet eda tant cy bua d ode EEN snap tind dense 140 12 3 5 Incorporation 502 esses EA ENNEN EE EE dee EE ENEE Reg tr rennes rs 141 May 15 2014 16 831 SPH RES INSPECT Design Document 4 13 Appendix D Halo Interface Board Layouts CK CL eeee ee eere eene 142 13 1 Unified PCB ELTER 142 13 2 Custom Eagle CAD Parts CK 5 1 11 11e ree pese ta ooa bana NEEN KAEE NEE bae a ha Ra Pei e ENEE AR Sa RR RR AER EEN 151 13 3 CMG PCB Schemat osier an eren eroi neant ua ee ee na no EECH aov ae ka aoa de gk ao an uai ane 152 14 Appendix E CAD Overview MK e ee eere eene eee eee ne eee nennen nuno nn entretenu 153 14 1 Integrated Assembly rere trant no eo enne oa neo ua eoe nu ka oo an EES 153 14 2 Subassemblies E EE 153 14 3 INSPECT Sensor Compohlents vcccssccecsssvensecesssocsse
22. Figure 29 INSPECT Integrated Testing Configuration May 2014 front view 16 831 SPHERES INSPECT Design Document 37 3 System Level Budget Allocations MC JB 3 1 Mass JB MK Table 2 Mass Budget Allocation outlines the mass budget allocation of the INSPECT system including the current best estimate CBE and margins of the subsystems Note that the mass budget below does not include Halo and SPHERES masses 4 525 kg and 4 828 kg respectively including batteries In addition masses in Table 2 do not include component wiring which will reduce the total remaining mass when finalized Table 2 Mass Budget Allocation Mass Budget Subsystems components and Allocated Allocated Less 1096 CBE kg Remainin Remainin structures and kg Margin kg g kg g 96 avionics VERTIGO Thermographic 0 419 0 481 53 4496 Camera Optical Rangefinder Total Allocated Mass kg Total Allocated Mass Less 10 Margin kg Total CBE Mass kg 8 079 Total Remaining kg 18 39 3 2 Power JB Table 3 Power Budget Allocation outlines the power budget allocation in terms of average and peak power of the INSPECT system including the current best estimate CBE and margins of the subsystems Table 3 Power Budget Allocation Power Budget Sub M udis Remaining Remaining systems p See Power W Margin W VERTIGO Optics 5 4 5 1 4 3 1 68 89 4 5 0 0096 Mount May 15 2014 16 831 SPHERES INSPECT Design D
23. Figure 6 Continuous Change of Depth Stimulus This continuous depth stimulus is covered in a unique pattern to allow for precision image overlapping For compounded stimuli depths of 5 cm 0 cm and 10 cm from the neutral plane of the board have been selected as discrete depths for stimuli This allows for the following ranges of depth changes to be observed 1 0 cm to 5 cm 5 cm depth change More stringent than requirement 2 Ocm to 10 cm 10 cm depth change At requirement 3 5cm to 10 cm 15 cm depth change Less stringent than requirement May 15 2014 16 831 SPHERES INSPECT Design Document 23 2 3 1 1 3 Thermal Stimuli Thermal resolution will need to be tested both in terms of amplitude of the stimuli and the size of the stimuli The heated areas will be of the following sizes 1 3x3 cm More stringent than requirement 2 5x5 cm At requirement 3 8x8 cm Less stringent than the requirement The amplitude of temperature difference shall be ambient lab temperature ambient lab temperature 5 C and ambient lab temperature 10 C This gives the following temperature gradients 1 5 C At requirement 2 10 C Less stringent than the requirement Though no non zero thermal gradients are less than the at requirement level the bounds of the stimuli are predicted to be much less discrete than the non thermal stimuli This will give an opportunity to detect smaller temperature gradients than those explicitly defined by the tempe
24. The data is transmitted as an array of unsigned int values with each value in the array representing the intensity value for a pixel Via OpenCV the intended image processing system for INSPECT the data is stored in matrix form Table 23 Thermographic Camera Data Rate Breakdown KAF ACEL EE 512Mbps Rate Mbps Notes Total Spent 2 46 4 3 8 bits pixel 14 bits pixel Budget Remaining 99 52 99 16 4 1 4 6 Software AW May 15 2014 The ThermoCam is compatible with GigE Vision protocol for data transfer via Ethernet and supports GenlCam camera control protocol which provides a generic API The ThermoCam was be commanded by the VERTIGO Avionics Stack using the Pleora eBUS SDK 3 1 7 which is compliant with the ThermoCam s GigE Vision and GenlCam standards The Pleora eBUS SDK is available for the Linux Red Hat operating system but can be made compatible with the Linux Ubuntu operating system by linking appropriate libraries as outlined in the INSPECT Interface Controls Document As displayed in Figure 55 via the Pleora eBUS SDK API commands are sent from the VERTIGO Avionics Stack GigE Vision Control Protocol GVCP command port to the ThermoCam ThermoCam data blocks are transmitted at a maximum rate of 60 Hz to the VERTIGO Avionics Stack and are received via the GigE Vision Streaming Protocol GVSP 16 831 SPHERES INSPECT Design Document 71 streaming port The eBUS Universal Pro Driver works
25. ThermoCam from being damaged from excessive current as it will not be able to draw more than about 1 4 A of current observed during MICPCB testing The layout of the MICPCB is shown in Figure 35 May 15 2014 16 831 SPHERES INSPECT Design Document 70 Table 21 Thermographic Camera Peak Power Breakdown KAF Peak Power Budget 16 5W Item Power W Notes FLIR A5 6 From Datasheet Regulator 0 78 Assuming 85 efficiency Total Spent 6 78 Budget Remaining 58 9 Table 22 Thermographic Camera Average Power Breakdown KAF Average Power Budget 5 5W Item Power W Notes FLIR A5 3 From M12 Testing Regulator 0 63 Assuming 85 efficiency Total Spent 3 63 Budget Remaining 34 096 4 1 4 5 Data and interfaces CL AW The ThermoCam uses Gigabit Ethernet to transmit data meaning that all four twisted cable pairs in the Ethernet CAT6 cable are necessary for data transmission The ThermoCam is connected to all eight pins of the RJ45 Ethernet port pairs 1 amp 2 3 amp 6 4 amp 5 7 amp 8 on the MICPCB which in turn is connected to the appropriate data pins on the Samtec ERM8 025 09 0 S DV K TR male 50 pin connector The data is then relayed back to the VERTIGO Avionics Stack via the ERF8 025 01 S D RA TR female connector on Halo Port 5 The ThermoCam sends 80 x 64 resolution images with a bit depth of either 8 bits per pixel or 14 bits per pixel at a maximum frequency of 60 Hz 6
26. all assembled subsystems including SPHERES VERTIGO Halo and the INSPECT sensor suite components on their respective Halo ports Note that components are depicted without wiring 2a 4 Figure 120 a and b Integrated INSPECT Assembly with Side View 14 2 Subassemblies 4 The base platform for INSPECT is the SPHERES testbed pictured in Figure 121 below The distance from the X face to the rightmost edge of the expansion port is 22 5 cm Z SPHERES Expansion Port CO Canister Figure 121 SPHERES Assembly The VERTIGO Goggles subassembly is pictured in Figure 122 followed by the VERTIGO Avionics stack subassembly in Figure 123 May 15 2014 16 831 SPHERES INSPECT Design Document 153 noii Figure 123 VERTIGO Avionics Stack Subassembly The Halo subassembly pictured in Figure 124 is shown with SPHERES Halo and the VERTIGO Avionics Stack The Halo structure is 43 4 cm wide from HP5 to HPG and 40 9 cm in height 3 Figure 124 Halo Subassembly with SPHERES and VERTIGO Avionics Stack May 15 2014 16 831 SPHERES INSPECT Design Document 154 14 3 INSPECT Sensor Components 14 3 1 Thermographic Camera A summary of the Thermographic Camera is depicted below along with the mounting structure as discussed in Section 4 1 4 3 Power LED AQ ma Mounting holes Camera che ET Ethemet on bottom face lens dede connection connection Figure 125 Thermogra
27. floor C 1 The system shall stabilize all sensors to have a blur constant of less than or equal to 1 see appendix for formula C 2 The system shall be able to translate in a controlled manner to a 1 cm accuracy C 3 System shall be able to control its attitude through three dimensional space in a microgravity environment to 0 5 degree C 4 System shall be capable of achieving an angular velocity of greater than 0 5 rpm but less than 9 rpm A 1 The actuators shall provide movement for sensors that require motor functions A 2 The system shall be capable of producing a torque of at least 4x10 5 Nm A 3 The system shall be capable of linearly accelerating at 0 02 m s 2 Test Procedure Refer to INSPECT Integrated System Test Report for full list 1 Setup Assemble telemetry beacons as required by the Concept of Operations see Figure 4 Clean flat floor see procedure from INSPECT Acceptance Test Report Configure SPHERES with the testing computer and USB communicator Place testing deck onto the air carriage and secure with clasp Mount the SPHERES to the Halo structure see Halo Assembly Sequence in INSPECT Integrated Test Report Mount and secure all subsystems in accordance with the ICD Check communication between SPHERES and host computer 2 Procedure Use multimeter to check voltages of all power components Power on SPHERES and all components May 15 2014 16 831 SPHERES INSPECT Design Document 124 Set SPHERES thruster air pr
28. forward facing sensors and the avionics stack operate for 30 minutes but CMGs have not been tested using power from Halo Testing scheduled for Verification Summer 2014 Needs to last for a significant amount of The suite shall be capable time on station in of performing 250 test order to evaluate the cycles over its operational possibility of l 2 Life Span life M 1 SPHERES X Analysis Verification Unverified Only 20 test cycles completed as of 14May2014 Each mode being Each system Concept of tested on the flat floor Operations mode shall be must be completed Flat Floor completed using no more without being Operation than one full set of fuel interrupted for l 3 Time tanks M 1 refueling Testing Verification Verified Total fuel consumed 29 of two tanks combined The suite shall not interfere SPHERES with battery or fuel Maintain SPHERES l 4 compartment compartments S 4 operations Inspection May 15 2014 16 831 SPHERES INSPECT Design Document 17 Verification Verified CAD model confirmation and visual inspection System Safety Requirements The system shall not The suite shall not interfere SPHERES with SPHERES thrusters or Maintain SPHERES l 5 actuators sensors S 4 operations Analysis Verification Unverified Final CMG wiring positions being designed to be implemented Summer 2014 The system shall be able to Allows for ground l 6 SSL Testi
29. future testing inside the ISS May 15 2014 16 831 SPHERES INSPECT Design Document 117 6 2 7 2 6 2 7 3 6 2 7 4 Personnel o Grace Krusell John Wenzel Alessandro Lira Hang Woon Lee James Krasner Melissa Kornspan Mic Byrne Matt Vernacchia Krystal Arroyo Flores Candice Kaplan Connie Liu O E 0 Gr GO OO Location The integrated test will be completed on the SSL Flat Floor testing facility in Building 17 of MIT Equipment Materials Refer to INSPECT Integrated System Test Report for full list 1 Test Board Refer to Figure 5 o Topmost patterned row shall consist of the irregular shape pattern VERTIGO can recognize and vary in depth from 5 to 5 cm in accordance with SEN 2 o First column on 10cm squares shall exhibit a 5cm x 5cm visual pattern the second column 2 5cm x 2 5 cm and third column 1cm x 1cm in accordance with SEN 3 o The first row of 10cm squares shall also be at a 5cm depth jutted out from the board and closer to the INSPECT path the second row on the board face Ocm depth and third row at 5cm depth realized by a square hole cut in the foam board with the visual stimuli attached at the back facing the front This is a second iteration on the design requirement dictated by SEN 2 that allows for simultaneous check with SEN 3 see second bullet o The eight aluminum plates located at the middle bottom section of the board test for SEN 4 with alternating temperatures of either 5 degrees C
30. on the Avionics Stack can be found in Figure 73 4 00 4X 50 089 314 40 UNC 28 THREAD THRU L 5 60 1 165 4X 0 089 Y 0 270 4 40 UNC 28 THREAD LENGTH BOTTOM Y 0 200 Figure 71 VERTIGO Avionics Stack Front View May 15 2014 16 831 SPHERES INSPECT Design Document 88 May 15 2014 DISTANCE BETWEEN ERF8 CONNECTOR MATING FACE AND AVIONICS STACK TOP FACE 0 210 Figure 72 VERTIGO Avionics Stack Side View p2 BATI gt gt USB VDS P LA USB VD5 N SW_BATT gt lt USB VD6 N USB VD6 P Iii M USB VD3 N USB VD3 P VDDTXRX UARTI 232 422 SELECT UART1_232TX 422TX UARTI 232RX 422RX RS 232 SOUT2 IR TX US RX 11A EXT p US RX 11B EXT a RS 232 SIN2 US RX 11 EXT UARTI1 232RTS 422TX US RX 12A EXT UARTI 232CTS 422RX US RX 12B EXT US RX 12 EXT gt USB VD4 N we 1 A USB VD4 P 2 N gt RE TD2 ERA Ce TD3N QE TDP TDO L TDO eegen lt gt DIN Wegen A DIP T T Figure 73 VERTIGO Avionics Stack Samtec 50 Pin Connector Pin Layout 16 831 SPHERES INSPECT Design Document 89 4 2 2 Power Interface JB LJ GP Halo can provide power to all of its 6 ports from its own battery packs Battery packs each provide 11 1V unregulated 1 5A or 5V regulated 0 5A This gives 16 65 W of power total at each Halo port A breakdown of the power distribution is included in 4 1 1
31. or 10 degrees C The plates also vary in size between 3cm 5cm and 8 cm which is below at and above requirement respectively for SEN 4 The two plates with visual stimuli attached to the aluminum will be full requirement check with a visual stimuli at requirement of 2 5cm x 2 5cm checkerboard pattern on the face of the board and therefore 1m away from the INSPECT sensors during maneuvers and at 5 and 10 degrees C to test noise equivalence temperature distance Note Each stimulus is subjected to truth testing prior to the test to allow verification of accuracy readings from each of the sensors May 15 2014 16 831 SPHERES INSPECT Design Document 118 6 2 7 5 Requirement Verification Requirement ID ISS 4 S 3 H 1 H 2 H 3 H 4 SEN 1 SEN 2 SEN 3 SEN 4 SX 1 SX 2 SX 3 SX 4 SX 5 May 15 2014 Table 41 Integrated System Testing Requirements Requirement Description The fully integrated system shall be capable of fitting in the 57 6 x 83 x 80 cm JEM airlock The system shall not exceed a peak power draw of 55 5 watts 11 1V and 5 amps Each suite component shall connect to Halo using the 4 hole square screw pattern Each suite component shall be able to connect to the Halo via USB 2 0 or Ethernet Each suite component shall operate no more than 16 65W and be able to convert operational current voltage from 11 1V 1 5A The suite shall not impose a force greater than 40N in the z direction to SPHERES All i
32. software and sensors need to be added to perform inspection navigation and characterization With help from technologies from the MIT Space Systems Laboratory and Draper Laboratories such as the Halo structure and CMGs the INSPECT system is the first step towards creating microsatellites that realize NASA HEMOD s vision F WM Figure 1 SPHERES operating inside ISS left SPHERES microsatellite middle concept of free flying autonomous systems derived from SPHERES architecture near ISS right 25 May 15 2014 16 831 SPHERES INSPECT Design Document 11 1 3 Team Organization MC JB Figure 2 outlines the organization and contributors of the INSPECT design team Contact information for all team members may be found in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 May 15 2014 C Cassidy Interviewee Interview 05 12 2013 J P E a A G R Mark O Hilstad The SPHERES Facility Description MIT Space Systems Laboratory 2013 B McCarthy SPHERES Halo Presentation Cambridge MA Feb 6 2014 B McCarthy and C Jewison MIT Space Systems Laboratory Cambridge MA 21 Nov 2013 B McCarthy Halo PDR MIT Space Systems Lab Cambridge 2013 B E Tweddle Computer Vision Based Localization and Mapping of an Unknown Uncooperative and Spinning Target for Spacecraft Proximity Operations Cambridge Massachuset
33. the ORF can be caused to occur during thruster firings when the Metrology system is already down to minimize the Metrology down time MV In the message based architecture message passing is used to ensure that the Metrology System is turned off before the ORF operates The VERTIGO Avionics stack sends a DISABLE METROL message to the SPHERES DSP and waits for a METROL OFF reply before operating the ORF After the ORF is finished the VERTIGO Avionics Stack sends an ENABLE METROL message to the DSP so that it can reactivate the Metrology system A limited and poorly documented message passing infrastructure exists between VERTIGO and SPHERES and could be extended to implement this architecture In order to improve the resilience to dropped messages it may be desirable for the messages to be sent repeatedly until a response is received rather than sent once MV May 15 2014 16 831 SPHERES INSPECT Design Document 63 Key IR Rcv interrupt disabled NT time S Qm Messages passed SPH2 between SPHERES time Figure 47 Message based synchonization of the ORF and the Metrology system MV VERTIGO Master SHPERE Set ORF to software trigger mode void onMsgRcv Message msg SR SetMode cam SR GetMode cam if msg type DISABLE METROL AM SW TRIGGER disableMetrology commSendPacket DISABLE METROL ack 0 while ack ertigo sendMsg METROL OFF while running if msg type ENABLE METR
34. the Samtec 50 Pin connector from the Halo port where it draws both data and power over USB The thinner end of the PCB which protrudes out towards the front of the assembly is reserved for the electrical interface to the CMG Controller over RS 422 connections May 15 2014 16 831 SPHERES INSPECT Design Document 83 T ia EH e o Be A Y m L 875 Figure 68 CMG PCB Footprint in JS NM 4 1 5 6 Software Overview AV MA Software infrastructure for testing of CMG usage on SPHERES both in MATLAB simulation and in the MIT Space Systems Laboratory hardware test bed has been developed by 16 851 and 16 831 Figure 69 shows the software layout of SPHERES using CMGs for attitude control and thrusters for position control Software was originally developed to control attitude in the z axis of SPHERES however it has now also been developed for rotation about the y axis which is the only rotational axis available in flat floor testing inside the Space Systems Laboratory This change in orientation was caused by the need to accommodate a CO tank on the air carriage test structure From the original SPHERES software changes were made to the following e Control Law Converts the state error into a set of force and thrust commands for SPHERES A standard PD controller is used with modified gains for the CMGs This control law outputs the necessary torques for a desired change in attitude e Mixer Standard m
35. to decrease the CPU utilization of the VERTIGO Avionics Stack as image data is received 13 The data is then stored on the SSD via SATA in a format accessible by OpenCV which involves creating a Mat object to store the image information of the data matrix including the matrix header and pointer VERTIGO Avionics Stack Return Data Blocks FLIR A5 GVCP GVSP Streaming Port Take Data GenlCam Software eBUS Universal GenAPI Pro Driver Command Figure 55 ThermoCam Software Flow Diagram The ThermoCam software can be accesssed via github https github com awassen INSPECT in the the ThermoCam folder The main folder holds the ThermoCam Makefile and build script while a secondary folder containing a makefile and the main C code Instructions for implementing the code are found in the INSPECT Interface Controls Document When the ThermoCam software is executed the VERTIGO Avionics Stack is commanded to search for the ThermoCam and if detected to connect to it The software then sends a command to open a stream between the VERTIGO Avionics Stack and the ThermoCam and populates the stream with buffers At an image frequency specified in the ThermoCam software each buffer is filled with one frame s image data consisting of an array of unsigned int values each representing an intensity value for one pixel in the frame While the minimum image frequency to meet INSPECT requirements is 1Hz
36. to demonstrate liveness of a connection but not transmit any meaningfull messages GP A communications software test plan was developed to safely test and integrate the CMGs with VERTIGO and eventually SPHERES However this test plan was largely left unimplemented except for the software development described above by May 2014 due to time constraints Mass JK NM MA The mass of the ADCS subsystem is divided among two Halo ports each containing two CMGs with enclosures swivel plates standoffs and the ribbon cable wiring to be run between HP2 and HP4 The PCB and control board will occupy a single port Table 30 CMG Mass Budget Mass Budget 6kg Item Mass kg Notes LEO H 120 CMGs 2 80 4 CMGs weighing 700 grams each LEO Controller Board 0 50 1 Controller Board Mounting Hardware 1 80 Estimated Includes Standoff Swivels Screws Etc Total Spent 5 10 Budget Remaining 15 4 1 5 9 Financial Budget JK NM The CMG attitude control system was procured by Draper Laboratory for the 16 851 project which then gave it to 16 83x As a result the CMG system itself wheels drive electronics has no monetary cost to INSPECT The CMG system has a value of over 40k Machined components are machined in the Aero Astro machine shop and thus incur no monetary expense as well Table 31 CMG Financial Budget D UT ET SIT e e 3000 Item Cost USD Notes TTL to RS422 Converter 75 81 4 con
37. 00 400 500 600 Time ms ORF Thermacam VERTIGO 700 600 900 1000 Figure 75 Worst case delay analysis presented as a timing diagram as part of a 1 Hz operation cycle for all May 15 2014 sensors 16 831 SPHERES INSPECT Design Document 93 4 2 5 8 On board Processing using the VERTIGO Avionics Stack HL INSPECT API VERTIGO INSPECT Ele Source Code v Source Code p N Linux System Figure 76 Software Design for INSPECT operations using the VERTIGO Avionics Stack BC GP 4 2 5 4 The VERTIGO Goggles program is mainly composed of two high level sets of programs Goggles Daemon and Goggles Program Files GPF The Goggle Daemon runs on the background and supports GPF The main functionalities of Goggles Daemon include running the Linux Daemon communication hardware monitoring GSP support debug service and error reporting and fail safes GPF provides workspace for various Goggles Linux Software executable files and parameters files that can be readily implemented and compiled The ThermoCam and the ORF APIs can be installed under GPF This allows simultaneous thread actions of each subsystem The VERTIGO Optics Mount takes four different values per pixel x y D G where D and G refer to the depth and the gray scale respectively The ThermoCam captures x y T where T refers to the temperature The ORF takes x y D G where the purpose in mainly focused on grabbi
38. 12 I O and RJ45 Ethernet connectors into their hubs The major considerations that went into the mount design were fitting the required sensors and MICPCBs weight avoiding plume impingement and ease of manufacture To address these concerns the mounts were designed to bring the sensors out of the plume impingement zone of the SPHERES thrusters They were water jetted from aluminum plates with excess aluminum cut out when possible to reduce weight Aluminum was chosen over plastic materials despite the slightly harder manufacturing process because aluminum is a better conductor and can be used to act as a heat sink to conduct heat away from the FLIR A5 both extending the camera s operating time and preventing inaccurate temperature readings caused by overheating May 15 2014 16 831 SPHERES INSPECT Design Document 68 Figure 52 The CAD model for the sensor mount with the Thermographic Camera in it for scale Holes on the 4 1 4 4 bottom plate allow for installation of the Thermographic Camera NC 119 75 177 95 Figure 35 Thermographic Camera Mounting Structure dimensions in mm NC The mount connects to the Halo Port Footprint Figure 31 via the outer set of inboard to outboard male mounting screws which screw into female threaded holes on the back plate of the mount structure Three of the four inner holes are used to secure the MICPCB in place so that the male 50 pin Samtec connector on the board can make a sec
39. CB for both the Optical Rangefinder ORF sensor as well as the Thermographic Camera ThermoCam This enables the MICPCB design to be mass produced at a lower price and interchanged between the various sensors CL May 15 2014 16 831 SPHERES INSPECT Design Document 46 Figure 35 Multiple Interface Connection PCB MIC PCB CL CK GP The MICPCB has three main functions route power route data and in the version with health monitoring monitor and indicate health of power to sensor The MICPCB has one switch to provide power to the entire board and because the ThermoCam and ORF will each have their own PCB each sensor can be turned on or off independently using the PCB or using the power Switch on each Halo port However as of May 2014 Halo does not have functioning individual power switches so the ORF and ThermoCam were independently switched on via the switches on the PCB In the health monitoring version a lit green LED will serve as a visual indicator when the board is turned on and there is power at the output of the voltage regulator i e power available for the attached sensor this can be seen in the health monitoring PCB just before the screw terminal which delivers power to the sensor In addition the health monitoring version also features a red LED which lights up when a fuse is tripped indicating a problem and no power being delivered to the sensor As of May 2014 the MICPCB was tested and integrated into the entire syste
40. ECT Test Board May 2014 System Field of Views The combined field of view created from individual sensor specifications as well as sensor placement is 33 55 H x 35 56 V From a distance of 1 meter this is equivalent to 59 53 cm H x 64 14 cm V Limiting factors for horizontal field of view include both individual sensor field of view and sensor placement The center of the horizontal field of view is located 14 37 cm from the center of the system 16 831 SPHERES INSPECT Design Document 25 Thermal Figure 9 Horizontal Field of View All sensors are located the on the same horizontal plane This leads to only sensor field of view to be the limiting factor The FLIR A5 has the smallest vertical field of view and thus is the limiting factor BE 64 14 gs 0 20 40 60 80 100 120 Figure 10 Vertical Field of View 2 3 2 Nominal Operations JW 2 3 2 1 Procedure Overview The objective of INSPECT 16 83x missions is to simulate inspection maneuvers that will be traceable to testing missions aboard the International Space Station ISS The mission is split May 15 2014 16 831 SPHERES INSPECT Design Document 26 into 5 steps to coordinate pre maneuver maneuver and post maneuver operations by INSPECT 16 83x Step 1 Pre mission During this phase the operator will decide the target object that will be inspected by the system He or she will also select and or program one or more of the pre defined inspection maneuvers
41. ECT sensors and actuators had to stream their data through alternative connections for the duration of integrated testing To accomplish this the Optical Range Finder ORF and Thermographic Camera ThermoCam subsystems were connected via their respective Ethernet cables to a central Ethernet switch Figure 92 and Figure 93 which was then connected via a third Ethernet cable to the functioning Ethernet port on HPG The switch was stored adjacent to Halo Port 3 where it would not interefer with SPHERES thrusters The location of the switch and sensor Ethernet cables are shown in Figure 23 The switch power cable which was connected to a wall outlet can be seen leading off from the vicinity of the switch in the top of the figure Barely visible is the third Ethernet cable connecting the switch to the Ethernet port on HPG which was run underneath the testing structure The CMGs accomplished data transfer through a direct connection to a CMG designated computer The cables for this connection can be seen in Figure 22 the red and black cable pair leading off in the right side of the figure KAF May 15 2014 16 831 SPHERES INSPECT Design Document 33 Figure 23 ORF ThermoCam and Ethernet switch connections INSPECT also utilizes VERTIGO Visual Estimation for Relative Tracking and Inspection of Generic Objects to carry out observation and inspection tasks VERTIGO designed to interface with the SPHERES expansion port includes an Avionics Sta
42. ES INSPECT Design Document 82 Figure 67 CMG PCB Schematic NM GP The PCB shown in Figure 67 CMG PCB Schematic NM GP outlined in Figure 66 CMG PCB Board Flow Diagram NM works in a two step process It first converts the USB signals from Halo to UART TTL and then from UART TTL to RS 422 The first step uses a FT232R chip commercially available from FTDI Chip It takes in the transmit and receive USB data lines and returns the same transmit and receive TXD RXD as UART TTL and well as a handshaking signal pair RTS CTS as UART TTL The second step requires 2 ADM488 chips from Analog Devices One chip converts the transmit and receive TXD RXD UART TTL signals to transmit and receive TXD RXD in RS 422 The other chip converts the handshaking signals RTS CTS from UART TTL to RS 422 In addition the PCB draws two separate power sources from the Samtec 50 Pin connector The 5V source is used to power the FT232R and ADM488 chips on the PCB itself while the 11 1V source is fed directly to the CMG Controller Board for overall system power The 11 1V source must be stepped up to 12V using a Delta S24SE12002PDFA DC DC power regulator to meet the specifications of the CMGs This is the same voltage regulator used in the ORF Thermocam MICPCB The PCB also includes all necessary grounding connections for system safety The allotted footprint of the PCB inside the CMG Halo Standoff Box is shown here in Figure 68 The PCB is aligned with
43. Engage and Reorient Experimental Satellites SSL Space Systems Laboratory ToF Time of Flight TORC Tiny Operationally Responsive CMGs UDP Universal Docking Port VERTIGO Visual Estimation for Relative Tracking and Inspection of Generic Objects May 15 2014 16 831 SPHERES INSPECT Design Document 10 1 Introduction 1 1 Mission Statement MC MK The mission of INSPECT is to prototype and test a sensor actuator suite as the first step to addressing NASA Human Exploration and Operations Mission Directorate HEOMD mission need for free flying autonomous systems for extravehicular inspection and characterization 1 2 Motivation and Vision MC MK As more technology is developed for in space applications NASA HEOMD envisions retrievable free flying research platforms for the ISS and other host vehicles where scientific and technical research is conducted in a stand off location a location in free space approximately 5 km away from the host vehicle or around the host vehicle itself Conducting research in a stand off location is advantageous because of less vibration and contamination ability to support large deployable structures ability to test relative sensing over long distances ability to exercise rendezvous and circumnavigation or ability to observe the host carrier from that stand off position 1 Thus there is an incentive to construct free flying autonomous systems that operate at these stand off locations in
44. Feb 2002 Online Available http ssl mit edu spheres library cdr SPHERES CDR Final pdf M T Vernacchia ORF Metrology Test Report MIT Department of Aeronautics and Astronautics 16 831 Class Cambridge 2014 D Sternberg Interviewee SPHERES exposure to Infrared Light Interview 3 March 2014 Flir User s Manual Flir Ax5 series Online Available http support flir com DocDownload Assets 86 English T559770 en US AB pdf Accessed 25 11 2013 eBUS SDK Programmer s Guide 17 September 2012 Online Available ftp 80 254 171 53 Pleora eBUS SDK 3 ebus sdk programmers guide pdf Accessed March 2014 Honeybee Robotics Quote for LEO H120 T50 CMGs Longmont CO 2013 Honeybee Robotics Draper CMG Array Command and Data Specification Honeybee Robotics Spacecraft Mechanisms Corporation 2014 D Hayhurst VERTIGO Goggles Avionics Stack ICD MIT Space Systems Lab Cambridge MA 2010 A R a M G U Tancredi Carrier based Differential GPS for autonomous relative navigation in LEO in A AA Guidance Navigation and Control Conference 2012 T S T S M V Samuel Schreiner Hardware Demonstration of an Integrated CMG and Thruster Control System 16 851 Cambridge MA 2013 FLIR Systems Inc Technical Data Flir A5 f 5 mm 17 10 2013 Online Available http support flirrcom DsDownload Assets 62205 0101 en 41 pdf Accessed 25 11 2013 Veracity UK Ltd Veracity White Paper 002 PoE Explained
45. GP iacet eee tette ee eder p ce e eiae m eden pu Goats ches 90 4 2 3 Power Requirements cce dette esti ces ete odode be cee ete nent La ires 91 4 2 4 SPHERES On Board Processing MA 91 4 2 5 INSPECT Data Flow GP BC HS ins 92 p PEE ee RI EE E 95 4 3 1 Balodnterfaces JB NC tte te ter ote e teet tt te eR d n 95 4 4 Thermal Considerations HM MK NC eeeee eene eene enne nnn nennen nnn nnns sett ne nenas 95 4 41 Overview MK HM et ee e ees e cen o AO Aaa oio 95 4 4 2 Assumptions HM updated by MK 96 4 4 3 Method of Thermal Analysis NC MK ins 96 4 4 4 Thermal Analysis NC HM 97 5 Risks and Mitigations sise screen toux rk aen XE anb Dun ca ka En dee EE 97 5 1 VERTIGO Goggles HL iioi ei ENNER 97 5 2 Optical Rangefinder ORF MV eese ee eene eene enn eren nennen nennt nnns nno nunt rnnt 98 May 15 2014 16 831 SPHERES INSPECT Design Document 3 5 3 Thermographic Camera ThermoCam KAF ee KREE eene eee ee eene nnne nennen nnn 99 CS CMOS EE 99 KR System Level Risks MK este eoe ni sao poo roo oaa dno sopa do tuo pasivo eege EEN Nee etes 100 Er Jntesrationand Tests identitaire ten 101 6 1 Assembly Procurement and Integration Plan GK 101 6 2 Testing Plan IW CER 101 GOA MICPCB Testing CL CK EE 101 6 2 2 Imaging Sensor Software Integration and Testing HS 103 6 2 3 VERTIGO Stack Testing AL HL rettet t
46. Glass Table 6 2 3 4 Equipment Materials The Equipment necessary for VERTIGO Stack Testing is as follows e Laptop with SPHERES Halo GUI installed e Ethernet cable e SPHERES e INSPECT grade air carriage e Halo structure e VERTIGO Optics Mount for VERTIGO team single component stack testing only e VERTIGO Avionics Stack e USB Flash Drive e Charged Nikon rechargeable battery pack at least 10 batteries e SPHERES battery shells sufficient rechargeable AA batteries e DC Power Source May 15 2014 16 831 SPHERES INSPECT Design Document 105 In addition to the equipment and materials listed above each subsystem will need equipment specific to its needs ORF Team e MESA SR4000 ORF e Power and data interface board MIPCB to connect the ORF to the Halo port e Wiring to connect the ORF to the MICPCB and to the central Ethernet switch e ORF mount structure ThermoCam Team e FLIR A5 Thermographic Camera ThermoCam e Power and data interface board MICPCB to connect the ThermoCam to the Halo port e ThermoCam mount structure CMG Team e Four LEO H120 T50 Control Moment Gyroscopes CMGs e Structures CMG mounting plates e Power and data interface board for CMG PCB 6 2 4 CMG Single Component Testing Structures Mock Halo Faces SLOSH inspired Cradle Propulsion Deck Figure 85 CMG Flat Floor Single Component Testing Structure Figure 86 Bare CMG Flat Floor Testing Structure Top shows the 90 degree relationship between the m
47. INSPECT Mission and Systems Requirements JW JB MC eee ecce eene eene nennen 15 2 3 Coricept of Operatioris 2 i tese oe ite u ru sia h naui adeo aras o De pa aao CERS NEE RR RR Ra DRE RE Ee 21 2 3 1 Operating Environment JW GK ins 21 2 3 2 Nominal Operations UW 26 2 3 8 Contingency Operations UW 31 2 4 Configuration Overview MK KAF eee eene e rennen eene nennen nnn nnn nn nnns n sunu sn senten 31 3 System Level Budget Allocations MC JB 1ceeeeeee eene eene eene nennen nennt 38 LERNEN FE SUM S E ETT ENEE ENEE RE eEde EE EEEe ee 38 LEE TT e TC 9E 38 3 3 Data Rate and Data Processing JB sssssscssssssssssssssececcseacssssssseceeseescanssssseseesssenansssseesees 39 3 4 Finances HB tege ere co eo enne tetes Age deed 41 4 Subsystem Design lisses eet eet eege 41 LS E EU E e E er nt en re iii re le stns se 41 4 1 1 H lo on SPHERES JB suen sets ete eerte rhe eer E re een ee aen 41 4 1 2 VERTIGO Goggles AL HS eue otic tre i b ue oder put eon tdt tet 51 4 1 3 Optical Rangefinder MV HS MK KH 55 4 1 4 Thermographic Camera KAF TW NC CL AW 67 4 1 5 ACDS CMGs RN JK MK JS NM Hei 74 4 2 Avionics and Communications cceeessseceerssscceccssscccecssssccenssseceessssecesessceceasesseceasesesseaasnss 87 4 2 1 Data Interface LJ GP sui teet te ctt i eek ed dn i teet qd 87 4 2 2 Power Interface JB LI
48. Integrated Navigation Sensor Platform for EVA Control and Testing INSPECT for SPHERES Design Document May 16 2014 Matthew Abel MA Krystal Arroyo Flores KAF James Byrne JB Blake Chambers BC Meera Chander MC Nathan Colgan NC Brent Edelman BE Jason Elizalde JE Katherine Hobbs KH Lachlan Jardine LJ Candice Kaplan CK Melissa Kornspan MK James Krasner JK Grace Krusell GK Hang Woon Lee HL Alessandro Lira AL Connie Liu CL Herbert Mehnert HM Nathan Miller NM Rebecca Navarro RN George Pantazis GP Joel Santisteban JS Ho Chit Siu HS Anthony Venegas AV Matthew Vernacchia MV Travis Wagner TW Alex Wassenberg AW John Wenzel JW CSSS Department of Aeronautics and Astronautics Massachusetts Institute of Technology 16 831 Space Systems Development Executive Summary GK MK The NASA Human Exploration and Operations Mission Directorate HEOMD is invested in researching technologies that could reduce risks associated with astronaut spacewalks One of these technologies envisioned by the directorate is an autonomous system capable of inspecting the exterior of space hardware a common reason for sending an astronaut outside of the International Space Station ISS The INSPECT system an Integrated Navigation Sensor Platform for Extravehicular Control and Testing has been developed as a first step in the progression towards developing a system capable of operating outside of the I
49. May 15 2014 16 831 SPHERES INSPECT Design Document 135 Honeybee CMGs 0 626 0 405 0 0 1467 16 76 Marylano Aerospace W Sas i0308 0208 0 561 47 24 1002 wheels RW 0 01 0 025 0 020 0 327 0 382 3 53 RW 0 03 0 039 0 043 0 409 0 2 083 32 42 RW 0 06 0 047 0 202 0 572 0 2 917 71 61 Clydespace 0 313 0 811 0 540 0 2 75 105 1 3 Clydespace z axis 0 001 0 174 0 078 0 573 877 2 13270 SSBV 0 688 0 087 0 074 0 459 5 90 38 AraMiS ADCS 0 119 0232 0 229 0 1 167 16 14 Table 49 the magnitude of the mass power cost and control authority have been normalized and then multiplied by a factor based on the worst parameter ratio compared to the respective budget Note that AraMiS ADCS would have to be less than 14000 making it an unlikely candidate Based on the tradespace above the Honeybees CMG were chosen May 15 2014 16 831 SPHERES INSPECT Design Document 136 12 Appendix C KH This section lists the payloads which we have chosen not to use on the final version of INSPECT For each not selected payload the following information is provided Purpose relevance to INSPECT Driving requirements Trade study Justification as to why it is not a part of the system How it can be incorporated if desired gui oa eeng 12 1 Radio GPS GP 12 1 1 Purpose and Relevance to INSPECT GP GPS allows for the localization of a SPHERES in free space and the sub
50. OL enableMetrology Shut off the metrology Spheres sendMsg DISABLE METROL Spheres waitOnMsg METROL OFF commSendPacket ENABLE METROL Take an image with the ORF SR Acquire cam Reactivate the metrology gspProcessRXData default rfm packet Spheres sendMsg ENABLE METROL packet if packet PKT CM METROL OFF ack 1 Figure 48 pseudocode for the message based architecture MV In the timer based architecture the SPHERES DPS and VERTIGO track the time since the test start in their internal clocks At fixed time intervals the VERTIGO stack operates the ORF and the DSP shuts down the Metrology system MV May 15 2014 16 831 SPHERES INSPECT Design Document 64 4 1 3 6 Key IR Rcv interrupt disabled SPH1 a internal clock time Clocks synced SPH2 iw in 1ms internal clock e 777 wem Figure 49 Timer based synchonization of the ORF and the Metrology system MV A VERTIGO All SHPERES Set ORF to software trigger mode Record test start time SR SetMode cam SR GetMode cam waitForTestStart AM SW TRIGGER startTimer timerCallback Record test start time waitForTestStart startTimer timerCallback void timerCallback disableMetrology sleep ORF acquisition time void timerCallback enableMetrology Take an image with the ORF SR Acquire cam Figure 50 pseudocode for the timer based architec
51. PHERES INSPECT Design Document 140 12 3 5 Incorporation If incorporated multiple 3 5 proximity sensors would clip on to Halo They would be pointed in different directions to detect obstacles in as many different directions as possible Power and data interface would both be through USB 2 0 some proximity sensors would have to have custom made interfaces that would allow them to connect to a USB 2 0 port Unlike for hazcams lighting would not be a limitation for proximity sensors as they can operate in the dark May 15 2014 16 831 SPHERES INSPECT Design Document 141 13 Appendix D Halo Interface Board Layouts CK CL 13 1 Unified PCB Iterations CK It should be noted that not every iteration of the MICPCB designed is posted below This is largely due to problems within the Eagle CAD iterations of the MICPCB and multiple changes happening in each new version cause some versions to not be saved For these reasons versions 15 and 16 are not posted below Additionally the MICPCB versions used for testing and designed for the next iteration v18 and v19 are not posted below because they can be seen in section 1 1 1 1 as Figure 35 and Figure 37 No versions of the PCB that were not unified are posted in this document because it was decided early in the design process to design a board to power both the ORF and ThermoCam sensors individual PCBs for each sensor are not relevant to this paper The PCB versions are in chronological or
52. PHERES INSPECT Design Document 66 PCB Breadboarding 133 38 Various components to test the PCB design on a Components breadboard MESA SR4000 4065 05 The Optical Rangefinder sensor MESA Imaging s Swiss Ranger 4000 PCB Surface Mount 84 93 MIC PCB Surface Mount Components Components MIC PCBs 97 22 MIC PCBs Ethernet Connector for 14 79 Ethernet Connector to connect MIC PCB to the ORF PCB to ORF ORF Power Connector 24 38 Power Supply Connector for ORF for PCB to ORF testing for PCB to ORF tests Total Spent 4483 91 Budget Remaining 33 5796 4 1 4 Thermographic Camera KAF TW NC CL AW Driving Requirements and Relevance to INSPECT KAF The thermographic camera ThermoCam allows INSPECT to take thermographic images of its 4 1 4 1 environment and transfer these images to the VERTIGO Avionics Stack for processing where the data can be analyzed to identify temperature extrema within the camera s field of view The driving requirements for the ThermoCam are listed below in Table 20 Requirements SEN 1 and SEN 4 ensure that the system is consistent with the other subsystems included in the INSPECT suite and requirement SEN 5 outlines the resolution limits desired for the thermographic images Table 20 Thermographic Camera Driving Requirements All imaging sensors shall Expectation of 30 have a minimum field of degree rotation per view of 33 degrees by 33 SX 1
53. Power Morse lines ulato egulator out Mother board in out Data lines in out 1 5A b Polyfuses N LETT HP2 HP4 HP3 and Board Board LED in out in out in out Figure 32 Halo Power Board Circuitry 5 4 1 1 5 Data and Interfaces JB The positive X axis of the SPHERES platform connects via the expansion port to the VERTIGO Avionics Stack which provides computation and data routing for all six Halo ports The Samtec ERF8 025 01 S D RA TR on each port Figure 73 has Ethernet pin pairs at S 39 amp 41 42 amp 44 45 amp 47 and 48 amp 50 with a ground pin next to each Ethernet pair It also has USB pin pairs at S 4 amp 6 and 10 amp 12 UART pin pairs are found at S 22 amp 24 and 30 amp 32 for connection to the SPHERES DSP The Ethernet pins serve as one of two data transport system transporting data via pin pairs 1 amp 2 3 amp 6 4 amp 5 and 7 amp 8 The Control Moment Gyroscopes CMGis utilize a control board which interfaces via an RSS 422 connector This necessitates the use of an additional Printed Circuit Board PCB to transfer data to USB and connect the male Samtec ERM8 025 09 0 S DV K TR to the female connector on the Avionics Stack ERF8 025 01 S D RA TR This design is discussed in detail in section 4 1 5 5 More information on Halo s data interfaces can be found in the Halo Design Document May 15 2014 16 831 SPHERES INSPECT Design Document 44 VERTIGO 50 pin connectors
54. S hardware itself This modification presupposes hardware that would allow a wireless link between May 15 2014 16 831 SPHERES INSPECT Design Document 94 SPHERES and an external computer and modification on the software to modularize it enough to INSPECT API run ROS VERTIGO Ol Board Processor Figure 77 Software architecture for processing off board the VERTIGO Avionics Stack BC GP 4 3 Structures 4 3 1 Halo Interfaces JB NC The Halo system has six Halo ports for electrical data and mechanical interface The Halo Port footprint diagram found in Figure 31 outlines the mechanical interface It comprises two similar squares of screws with the inner square consisting of screw holes for outboard to inboard screw insertion A second outer square consists of screw holes for inboard to outboard screw insertion into additional threaded female screw holes on the peripheral subsystem being connected The Halo system includes four captive screws on each port face that join the peripheral system being attached and the Halo via the outer screw holes These screws are equipped with washers to ensure that they do not penetrate too deeply into the peripheral system which could potentially damage the systems NC A 50 pin ERF8 025 01 S D RA TR female Samtec connector is also present and facilitates both data and power flow both to and from the sensors via a PCB Each Halo port sits at a 45 degree angle to its neighbor s Three are orient
55. SS and serving the HEOMD s needs The sensors on INSPECT were selected to fulfill the mission level requirements to reduce risk by testing capability inside of the ISS prior to moving into the vacuum of space The INSPECT system is an addition to an existing microsatellite system known as SPHERES Synchronized Position Hold Engages Reorient Experimental Satellites built by the MIT Space Systems Laboratory These satellites have been tested aboard the ISS and were originally created to serve as a testbed for control algorithms The core of INSPECT is Halo a structure mounted onto SPHERES that provides six ports for attaching additional sensors and actuators The sensors and actuators of INSPECT include VERTIGO Visual Estimation for Relative Tracking and Inspection of Generic Objects an already designed and tested system for SPHERES that provides computing power and visual capability for INSPECT two pairs of Control Moment Gyroscopes CMGs that allow for attitude control an Optical Rangefinder ORF that provides depth perception mapping and a Thermographic Camera that produces a 2D thermal map These components comprise of five ports of the Halo and the sixth port face of the Halo structure will be dedicated to a Universal Docking Port UDP The overall integrated system SPHERES Halo and INSPECT suite mass is 17 43 kg with the INSPECT suite components accounting for 8 08 kg of that total With an anticipated average and peak power draw of
56. V which is the current image processing package being used on VERTIGO Such a result May 15 2014 16 831 SPHERES INSPECT Design Document 103 would allow current and future OpenCV processing to be done on all the sensor data at once and build on an existing platform that has already been proven to work with VERTIGO To this end certain software development and implantation steps were taken by all sensor teams The ORF VERTIGO and ThermoCam teams were able to successfully implement their software simulatneously on the VERTIGO Avionics stack in individual terminal windows AW 6 2 2 1 Integration and Testing Milestones Install sensor driver on VERTIGO emulation Verify sensor communication with VERTIGO emulation VERTIGO emulation commands sensor to take an image with GUI VERTIGO emulation commands sensor to take an image with API Pass data from sensor to VERTIGO emulation in OpenCV accessible format Store data from sensor on VERTIGO emulation computer s hard disk All steps repeated on VERTIGO Avionics Stack DON gn m oe 6 2 3 VERTIGO Stack Testing AL HL 6 2 3 1 Objective The purpose of VERTIGO Stack Testing is to demonstrate the functionality of the peripheral systems when connected directly to the VERTIGO Avionics Stack Each subsystem must demonstrate its ability to individually send and receive data to and from the Avionics Stack The Avionics Stack must not only be capable of commanding each peripheral system to perform its tas
57. Verified Software data alignment successful and data output in format compatible with Verification standard autonomous identification protocols as well as human visible identification INSPECT shall provide a System must assess means of assessing when it can no longer SX Health functionality of its components perform its mission 3 Monitoring as a form of health monitoring M 1 safely Analysis Unverified Printed Circuit Boards designed and not tested successfully for health Verification monitoring properties INSPECT shall provide a System needs to test SX functional API for the testing of software for future 4 Algorithms future software M 1 missions Analysis Verification Verified Software saved to Sata drives 10 and 11 with support for future software Guest scientists will INSPECT shall provide a program navigation SX Navigation platform for navigational paths INSPECT must 5 Platform algorithm development M 1 support this Analysis Verification Verified Software data alignment successful and data output in format compatible with standard autonomous navigation protocols The system shall be capable of operating for no Needs to limit the amount of fuel and power used by INSPECT so that ISS fewer than 30 minutes future EVA operations Operation without refueling or are a reasonable l 1 Time recharging M 1 amount of time Analysis Unverified All three
58. ace caused by outboard to inboard male screw insertion 7 3 25 cm b r 5 E Female i o 8 mounting holes 9 e E Male P thumb screws PES el Le En ris wre man i Figure 31 Halo Port Footprint Rotated 90 Clockwise 5 JB 4 1 1 4 Power and Interfaces JB The Halo port interface supports a 50 pin Samtec ERF8 025 01 S D RA TR connector Figure 73 with pins S 1 3 5 7 9 and 11 for power S 1 3 and 5 connect directly to the negative end of the Halo battery suite and S 7 9 and 11 connect directly to the positive terminal The total voltage provided out of these six combined pins is 11 1V at a maximum current of 1 5A per port Once 7 5A total is pulled from the batteries as a combined load from all six Halo ports a PPTC fuse resets and power is cut to the system Similarly at each Halo port once 1 5A is exceeded another PPTC fuse resets that individual Halo port without impacting any other Halo ports Ground terminals are also present on the 50 pin connector at pins S 2 21 37 40 43 46 and 49 Pin 1 of the female 50 pin connector embedded in the Halo port is located on the top right of the connector when looking directly at the Halo port outboard to inboard May 15 2014 16 831 SPHERES INSPECT Design Document 43 More information on Halo s power and interfaces can be found in the Halo Design Document Circuit Power Breaker Switch 7 5A SW Batt Lg
59. ale side view CL 11 Pin Signal Explanation 1 RET GB Camera PWR 2 PWR GB Camera PWR 3 SYNC OUT LVC Buffer 3 3 V 0 24 MA max 1 2 24 mA max E SYNC OUT GND RET GB Camera PWR 5 SYNC IN LVC Buffer 3 3 V 0 lt 0 8 V gt 20V 6 SYNC IN GND RET GB Camera PWR F 4 GPO 1 x opto isolated 2 40 VDC max 185 mA 8 GPO GP Input return 9 GPIO_PWR GP Output PWR 2 40 VDC max 200 mA 10 GPIO_GND GP Ouput PWR return 11 GPH 1 x opto isolated 0 lt 2 1 2 40 VDC 12 GPI GP Input return Figure 54 Mapping pin to signal only pins 1 and 2 are used with ThermoCam CL 11 The MICPCB includes a simple health monitoring system as seen in the MICPCB layout in Figure 35 Multiple Interface Connection PCB MIC PCB to give a visual indication if the PCB is not functioning correctly As of testing in May 2014 the health monitoring system remained untested due to manufacturing issues A PPTC resettable fuse with a 1 1 A maximum holding current a 1 95 A trip current and a 300 millisecond trip time Littlefuse 1812L110 16DR is used in conjunction with an LED The PPTC fuse will trip if the current being pulled through the fuse exceeds 1 95 A and an LED light will turn on indicating that all power must be cut and reset to the MICPCB in order to return functionality to the board and to the ThermoCam The maximum current limit of 1 67 A on the input side of the voltage regulators will also protect the
60. alo port off and then back on However due to difficulties resolving issues with the health monitoring system the health monitoring portion of the circuit was not populated beyond the fuse during MICPCB testing and integrated systems testing see Figure 35 or Figure 36 CL During MICPCB testing it was found that the S24SE12002PDFA voltage regulator acts as a protector for the sensors because it resets its current draw to OA if the current approaches about 1 5A This was deemed sufficient and appropriate to protect the sensors and the health monitoring system was deemed not absolutely necessary for integration of the MICPCB with each sensor In the future a health monitoring system will be implemented on the MICPCBs for each sensor as seen in Figure 37 CK Table 7 shows all components for the MICPCB but since the health monitoring section of the PCB was not populated the 910Q and 51kO resistors diode PNP transistor and LED were not used in the tested and integrated iteration of the MICPCBs The intent is to use these components to populate and test future iterations of the PCBs with the health monitoring system implemented CL CK The schematic of the integrated and tested MICPCB is displayed in Figure 36 The layout and schematic of the MICPCB with a health monitoring system are shown in Figure 37 and Figure 38 Table 7 MIC PCB Populating Components CK CL Component Description Part Number Samtec 50 Pin Connects
61. as not necessary as verification of ORF thermal requirements would also verify ThermoCam thermal requirements NC As a mature system already on the ISS the VERTIGO Avionics Stack and Optics Mount have already passed thermal testing as such further analysis was not deemed necessary To prevent overheating the VERTIGO electronics system has a forced convection system in the control box in addition to safety kill switch triggered at 60 C that cuts power to VERTIGO Table 36 Power Draw by Subsystem Component Average Power Maximum Power Draw Draw W Spec W Mesa SR4000 ORF 4 64 measured 14 40 spec FLIR A5 ThermoCam 3 measured 6 spec HoneyBee CMG 7 11 VERTIGO Optics Mount 1 45 10 8 allocated 16 831 SPHERES INSPECT Design Document 96 4 4 4 Thermal Analysis NC HM Using the Solidworks simulation on the Optical Rangefinder ORF in its mount it was found that given a total power draw of 12W the sensor reached equilibrium at approximately 305 K well below the maximum operating temperature of 323 K This simulation suggests that the ORF sensor will never overheat given adequate ventilation Furthermore all of the electrical components and the interface with Halo remained much cooler at around 297 K As such the ORF and ThermoCam are expected to operate without approaching maximum operating temperatures for our required mission length NC Figure 78 Thermal Analysis o
62. ble 5 Data Processing Budget Allocation 41 Table 6 Financial Budget Allocation sis 41 Table 7 MIC PCB Populating Components CK CL sisi 48 Table 8 VERTIGO Driving Requirements iii 52 Table 9 VERTIGO Component Masses iii 53 Table 10 VERTIGO Peak Power Budget sise 53 May 15 2014 16 831 SPHERES INSPECT Design Document 8 Table 11 VERTIGO Average Power Budget sise 53 Table 12 VERTIGO Data Rate Budget isa 53 Table 13 VERTIGO Data Rate Budget iii 53 Table 14 VERTIGO Financial Budget sise 55 Table 15 Optical Rangefinder driving requirements sssssssssssseeseeeeeen nennen 56 Table 16 Optical Rangefinder Peak Power Budget JB MV 59 Table 17 Optical Rangefinder Average Power Budget JB MV 59 Table 18 Optical Rangefinder Mass Breakdown MV CK nennen 66 Table 19 Optical Rangefinder Financial Budget MV CK KH 66 Table 20 Thermographic Camera Driving Requirements nens 67 Table 21 Thermographic Camera Peak Power Breakdown RAF 71 Table 22 Thermographic Camera Average Power Breakdown RAF 71 Table 23 Thermographic Camera Data Rate Breakdown KAF 71 Table 24 Thermographic Camera Mass Breakdown ssssssssessssseee ener nnne nnne nnne 73 Table 25 Thermographic Camera Financial Budget ssssnnssssnnsee st neserntenttt rnst tn rnnt tnnnnrtnnnntnn nennen annene nnne 73 Table 26 ADCS Driving Requirements iii 74 Table 27 CMG Peak Power B
63. ble of linearly Allows for system A 3 Acceleration accelerating at 0 02 m s 2 C 3 translation Testing May 15 2014 16 831 SPHERES INSPECT Design Document 74 4 1 5 2 Design Choice RN MK JK Honeybee s Low Earth Orbit LEO H120 T50 Control Moment Gyroscopes were chosen as the ADCS for INSPECT Figure 56 Honeybee LEO CMG They each provide a maximum control authority of 0 16 Nm 14 of torque which is higher than that provided by the SPHERES thrusters which can only provide a maximum torque of 2 thrusters 9 65 cm 0 11 N 0 021 Nm about a single axis CMGs provide a higher level of stability at a cost of roughly 50k The cost for the INSPECT CMGs will be covered by Draper Laboratories 16 83x and 16 851 collaborated to generate a design that would meet the requirements for both projects A trade study that aided in the elimination of other forms of attitude control can be found in 11 3 ADCS LJ in Appendix B 4 1 5 3 Structures JS Figure 57 16 851 CMG and Control Box Assembly Box 90 Configuration May 15 2014 16 831 SPHERES INSPECT Design Document 75 The entire structural assembly for INSPECT s ADCS can be viewed in Figure 57 Given the CMG s inherent sensitivity and momentum generating capabilities structural integrity modularity and vibrational dampening were the two dominating design factors for the CMG and CMG control box mounting interfaces From a high level the CMG mounting design must allow ea
64. by 2 Lt Bryan McCarthy USAF and the Space Systems Lab at MIT 5 Halo was chosen as a platform for INSPECT due to its uniqueness as a cohesive platform where multiple subsystems can be tested and operated simultaneously while also providing a means of combining and overlaying data collected from each subsystem in a central computer It has been developed specifically for the purpose of facilitating sensor and actuator suites such as INSPECT The power system supplied by Halo also enables greater mission duration and range of sensors and actuators than the much reduced power output available on SPHERES Finally Halo s 45 angled ports facilitates a Box 90 configuration for efficient deployment of the CMGs as shown in Figure 57 4 1 1 3 Structures JB Halo provides six Halo ports in a symmetrical pattern about the SPHERES platform Each Halo port consists of a 50 pin Samtec ERF8 025 01 S D RA TR female connector located at the center of two distinct square shaped mounting patterns The inner mounting pattern in Figure May 15 2014 16 831 SPHERES INSPECT Design Document 42 31 designed for use on the two central Halo ports Halo Port 3 and HPG enables screws to be drilled from outside the Halo port inward Alternately and designed for use on the four peripheral Halo ports Halo Ports 1 2 4 and 5 male screws protrude from the port enabling mounting of subsystems by screws drilling outboard away from SPHERES avoiding the wasted sp
65. can be implemented manually in situations where a component has encountered a malfunction that poses an immediate threat to other system components test operators or the testing environment 2 4 Configuration Overview MK KAF As mentioned in 1 2 Motivation and Vision the foundation for the INSPECT system is SPHERES which provides a platform for testing control algorithms and physical maneuvers on the ISS SPHERES is represented in Figure 20 below The right handed SPHERES coordinate system is the same coordinate system to be utilized for the integrated INSPECT system with the origin at the May 15 2014 16 831 SPHERES INSPECT Design Document 31 geometric center of SPHERES not including the SPHERES expansion port used to connect an external component to SPHERES the X axis pointing out of the SPHERES expansion port and the Z axis pointing upward The SPH RES shell displayed in orange below measures 21 3 cm x 21 3 cm x 21 3 cm SPHERES Expansion Port X CO Canister Figure 20 SPHERES Summary With SPHERES as the main testing platform INSPECT utilizes Halo a structure being developed by the MIT Space Systems Lab in parallel with the INSPECT suite in order to integrate multiple sensor components onto SPHERES Halo pictured in Figure 21 with SPHERES interfaces with SPHERES and provides six functionally identical ports with the exception of HPG which is designed to be used with the VERTIGO A
66. ch of two Halo ports to support two CMGs in both the Box 90 and Pyramidal configurations while completely enclosing the flywheel and gimbal for safety purposes that is four total CMG s two on each port Both of these ports will also be required to hold the drive electronics and PCB mounting assembly While only one set of drive electronics is required the redundant mounting assembly which will be machined in order to match the specs of the one sent by HoneyBee provides mass symmetry and ease of structural support As a result both pairs of CMGs will be mounted atop the control box sub assembly separated by a 1 8 inch swivel plate and two sets of dampeners as pictured in Figure 58 Figure 58 CMG Mounting Assembly The CMG mounting assembly will allow two enclosed CMGs to swivel into either the box 90 or pyramidal configuration depending on user preference The vibrational dampeners can be seen in Figure 58 as a barrier between the swivel plate and both the CMGs and the control box itself There are two total CMG mount assemblies Each consists of the following structural components May 15 2014 16 831 SPHERES INSPECT Design Document 76 CMG Mounting Plate Honey Bee CMGs CMG Enclosure a 1 of 12 p dampeners per assembly Honey Bee Control Box Enclosure Swivel Plate Figure 59 16 851 CMG Mounting Assembly Components Side and back views 4 1 5 3 1 Honey Bee Control Box Designed by Hone
67. ck shown in white in Figure 24 a with its own battery and processor The Avionics Stack interacts with the Optics Mount displayed in red in Figure 24 a which houses two stereo cameras VERTIGO is currently on the ISS and has proven functionality with SPHERES Figure 24 b depicts VERTIGO as it currently integrates with SPHERES in the INSPECT system the Avionics Stack interfaces with SPHERES and fits inside the Halo structure see Figure 21 while the Optics Mount connects to the corresponding Halo port HPG which routes power and data through Halo to the VERTIGO Avionics Stack INSPECT incorporates VERTIGO into the integrated system to serve as one in a set of sensors to aid in observation navigation and inspection tasks The utilization of VERTIGO in INSPECT is detailed in Section 4 1 2 MK May 15 2014 16 831 SPHERES INSPECT Design Document 34 Figure 24 a and b VERTIGO Goggles Assembly Avionics Stack with Optics Mount 4 and Integrated SPHERES VERTIGO System The VERTIGO Optics Mount normally connected through the Samtec 50 pin connectors on HPG had an unexpected failure during testing necessitating the use of an alternative Optics Mount This alternative set of cameras was mounted on top of the existing Optics Mount and secured to Halo using two daisy chains of zip ties Each camera was provided power and data lines through its own USB cable both of which were connected to the USB ports on the VERTIGO dongle This re
68. conds The on board computer utilized by INSPECT and outlined in section 4 1 2 1 1 operates on a 1Hz cycle it completes one cycle of processing every second This frequency May 15 2014 16 831 SPHERES INSPECT Design Document 39 dictates a maximum total processing time for all combined systems including on board SPHERES processing thrusting etc of 1000ms May 15 2014 16 831 SPHERES INSPECT Design Document 40 Table 5 Data Processing Budget Allocation Data Processing Budget S RTE ee CBE iced ubsystems rocessor Less 1096 ata Time ms Margin ms Connection VERTIGO Optics Mount 18 52 2x USB 2 0 Optical Rangefinder 38 89 1x Ethernet 70 65 Thermographic Camera 150 135 48 15 1x Ethernet CMGs 50 45 10 35 77 78 1x USB 2 0 Navigation Localization 300 270 270 0 0 00 Algorithm TOTAL 1000 900 680 220 24 44 3 4 Finances JB Table 6 Financial Budget Allocation outlines the cost budget allocation of the INSPECT system including the current best estimate CBE and margins of the subsystems Table 6 Financial Budget Allocation Subsystems components and Allocated Allocated Less CBE Remaining Remaining structures and 10 Margin avionics VERTIGO 1525 1075 238 89 Optical Rangefinder 7500 6750 4092 335 2657 665 39 37 Thermographic Camera 4500 4050 2312 495 1737 505 42 9096 CMGs 3000 2700 2633 8 97 55 Structures 7000 6300 292 43 6007 57 95 36
69. confirmed and recorded saturation levels The actuators shall provide Some sensors may Sensor movement for sensors that require increased field A 1 Movement require motor functions C 1 of measurement Inspection Verification Verified No sensors require motor functions The system shall be capable of producing a torque of at least 11x10 3 Based on SPHERES Testing and A 2 Torque Nm C 4 torque capability Analysis Verification Verified Testing and analysis confirms 0 34Nm total max torque well above requirement The system shall be Linear capable of linearly Allows for system A 3 Acceleration accelerating at 0 02 m s 2 C 3 translation Testing Verification Verified Fully laden mock system test verify requirement 2 3 Concept of Operations 2 3 1 Operating Environment JW GK The laboratory testing floor consists of a 5 m x 5 m octagonal epoxy surface The SPHERES INSPECT system can be mounted to air carriages which float on the glass surface by means of compressed gas This arrangement allows planar translation and single axis rotation about the y axis INSPECT nominal operations will consist of a 2 meter long landscape to be imaged from a distance of 1 meter away Adjacent to the testing surface will be a test landscape meant to simulate depth thermal and visual stimuli This testing landscape will allow for complete requirement testing as well as future research and developmen
70. d None too 90000 30 to 2000 3D Yes Laser safety scanning expensive Nene ton Limited laser LIDAR 3D flash im 100 000 30 to 500 3D Yes life Laser expensive safety Laser triangulation None range to 200 to 1D 2D or rangefinder short 10 000 S 3D MEE one Phase shift time of MESA SR4000 flight camera MESA SR4500 000 10 3n bs Structured light Nona tanget reng 4 3D No short The Hokuyo UTM 30LX MESA SR4000 and MESA SR4500 were identified as feasible sensors Next a trade study was performed between these sensors to identify the option which best matched our mission requirements May 15 2014 16 831 SPHERES INSPECT Design Document 132 Table 44 Optical Rangefinder candidate specifications bi MESA SR4000 MESA SR4500 Phase Hokuyo UTM 30LX Phase ToF ToF 2D scan LiDAR Avg Peak power W 9 6 12 12 120 8 4 12 Mass kg 0 510 0 850 0 370 Dimensions cm 6 5x6 5x6 8 11 9x7 5x6 9 6 0 x 8 7 x 6 0 Cost USD 4279 4849 5600 Angular range deg 69x56 69x56 120 Angular resolution deg 0 39 0 39 0 25 Distance range m 10 9 30 Distance resolution mm 15 40 50 Scan time millisec 20 33 25 Light wavelength nm 850 850 905 Works in bright light No Yes Yes Data connection USB or Ethernet USB or Ethernet Ethernet Data rate Mbit s 4 to 40 4 to 40 1 Table 45 Optical Rangefinder Pugh Chart Meets Halo 3 power constraint 3D scan w o 2 Yes Yes gimbal Sunlight 1 Yes Yes o
71. d back views 77 Figure 60 Honey Bee Control Box Top View is 77 Figure 61 CMG PCB Dimensions and Hole Layout in 78 Figure 62 Swivel Mounting Plate suisses 79 Figure 63 CMG Mounting Plate Drawing sisi 79 Figure 64 CMG Enclosure Drawing iii 80 Figure 65 Reinforced Enclosure sise 80 Figure 66 CMG PCB Board Flow Diagram NM is 82 Figure 67 CMG PCB Schematic NM GP 83 Figure 68 CMG PCB Footprint in JS NM iii 84 Figure 69 Block diagram of software system for SPHERES and CMG Payload 85 Figure 70 Avionics Outline JB s i t etes Rr eden deter e e ih ae Gale 87 Figure 71 VERTIGO Avionics Stack Front View sis 88 Figure 72 VERTIGO Avionics Stack Side View 89 Figure 73 VERTIGO Avionics Stack Samtec 50 Pin Connector Pin Layout 89 Figure 74 INSPECT Data Processing Flow HS sisi 92 Figure 75 Worst case delay analysis presented as a timing diagram as part of a 1 Hz operation cycle for CIE EIL 93 Figure 76 Software Design for INSPECT operations using the VERTIGO Avionics Stack BC GP 94 Figure 77 Software architecture for processing off board the VERTIGO Avionics Stack BC GP 95 Figure 78 Thermal Analysis on ORF Mount NC eene 97 Figure 79 VERTIGO Goggles Risk Fever Chart sis 98 Figure 80 Optical Rangefinder Risk Fever Chart sis 98 Figure 81 Thermographic Camera Risk Fever Chart nnns 99 Figure 82 CMGs Risk Fever Chart ait
72. dance Navigation and Control Conference 2012 T S T S M V Samuel Schreiner Hardware Demonstration of an Integrated CMG and Thruster Control System 16 851 Cambridge MA 2013 FLIR Systems Inc Technical Data Flir A5 f 5 mm 17 10 2013 Online Available http support flirrcom DsDownload Assets 62205 0101 en 41 pdf Accessed 25 11 2013 Veracity UK Ltd Veracity White Paper 002 PoE Explained 11 December 2008 16 831 SPHERES INSPECT Design Document 12 21 22 23 24 25 26 May 15 2014 Online Available http www veracityglobal com media 27197 vwp 002 20po0e 20explained pdf Accessed 24 November 2013 MIT Space Systems Lab Vertigo Avionics Stack Interface Control Document Cambridge 2012 Littelfuse Inc Data Sheet PTC 1812L Series 2012 Online Available http www littelfuse com data en Data Sheets Littelfuse PIC 1812L pdf Accessed 24 November 2013 T M S S Ruel Target Localization from 3D data for On Orbit Autonomous Rendezvous amp Docking Neptec Design Group Ltd Kanata Ont D L Miller MIT Space Systems Laboratory Cambridge MA 2013 D W Miller A White Paper for Exo SPHERES a Retrievable Free Flying Research Platform for ISS 2009 MIT Space Systems Lab UDP PDR Cambridge MA 17 Oct 2013 16 831 SPHERES INSPECT Design Document 13 Appendix A Contact Information Authority amp Communication e e Co
73. dependent of the host vehicle Multiple free flyers could be used for providing multiple viewpoints for inspection and platforms for additional research Free flyer autonomous systems can also be used for extravehicular inspection navigation and characterization around a host vehicle which would reduce the need for risky astronaut extravehicular activities EVAs For example on the International Space Station ISS the location flow rate and other details of an ammonia leak whether inside a pump package itself or from a defect in a truss structure segment could be more precisely determined before astronauts perform an EVA rather than relying on imprecise visual methods from inside the ISS Additional benefits include detection of electrical faults insulation deterioration and general monitoring of health and wellness of vehicle components 1 Thus the development of free flying autonomous Systems has potential to aid astronauts and reduce exposure to unidentified issues The MIT Space Systems Lab SSL Synchronized Position Hold Engage Reorient Experimental Satellites SPHERES 2 Figure 1 are eligible candidates for use as the base design for these free flying autonomous systems However modification is required for the SPHERES microsatellites to be able to address NASA HEOMD s mission For example they must be radiation hardened and designed to withstand the harsh space environment and the appropriate hardware instrumentation
74. der in terms of version numbering versions 1 through 17 of the unified multiple interface connector MIC boards ca be seen in the figures below CK 0000009000000000 o o6o0 000000000900000000000 Figure 101 Unified Printed Circuit Board v1 JB CK May 15 2014 16 831 SPHERES INSPECT Design Document 142 Figure 102 Unified Printed Circuit Board v2 JB CK Figure 103 Unified Printed Circuit Board v3 JB CK May 15 2014 16 831 SPHERES INSPECT Design Document 143 Figure 105 Unified Print Circuit Board v5 JB CK May 15 2014 16 831 SPHERES INSPECT Design Document 144 80 0 nuum Yir Vir ETHERNET o Ge k d 16 1U 16 D iim uti 4 ogELTA_S24 O 67 31 LE E E D VN C E P Positiv J p lt S C d IC O Unified PCB v6 DS 74 71 12 Figure 106 Multiple Interface Connector MIC Printed Circuit Board v6 CL NM 68 25 53 33 Figure 107 Multiple Interface Connector MIC Printed Circuit Board v7 CL May 15 2014 16 831 SPHERES INSPECT Design Document 145 68 25 53 33 60 95 Figure 109 Multiple Interface Connector MIC Printed Circuit Board v9 CL May 15 2014 16 831 SPHERES INSPECT Design Document 146 ETHERNET Figure 110 Multiple Interface Connector MIC Printed Circuit Board v10 CK CL GP 15 24 68 25 21 59
75. e deret ettet tee De et Matter eni e tente in es 100 Figure 83 System Risk Fever Chart esee entente inneren sinn innen en 101 Figure 84 SSL Glass Table sise 105 Figure 85 CMG Flat Floor Single Component Testing Structure sees 106 Figure 86 Bare CMG Flat Floor Testing Structure Top sssssssseeseeeeneen nene 107 Figure 87 CMG Flat Floor Testing Structure si 107 Figure 88 Alternative Bench Setup Utilizing Lazy Gusan 107 Figure 89 MICPCB and Halo setup CL en nennen nnne nennen 112 Figure 90 MIC PCB connected to Halo verifying 12 V output from PCB CL 113 Figure 91 ThermoCam being powered by MIC PCB and Halo blue indicator LED is on CL 114 Figure 92 10 100 Ethernet switch used for data transfer during MICPCB Halo sensor interface testing ThermoCam and VERTIGO Avionics Stack connected ports 1 and 5 respectively KAF CL 115 Figure 93 Gigabit Ethernet switch to be used during flat floor testing CL 115 May 15 2014 16 831 SPHERES INSPECT Design Document 7 Figure 94 ThermoCam left and ORF right in their mount structures with MICPCBs connected to VERTIGO Avionics Stack Optics Mount and Halo CL 117 Figure 95 Inspect Without Structural Support wiring not shown 120 Figure 96 Full System Testing Gtructure sie 121 Figure 97 Fully Integrated Testing Assembly 121 Figure 98 Fully Integrated Testing Structure COM nennen nennen 122 Figure 99 Profile area in
76. e directly connected to a computer 1 Connect one end of Ethernet cable to ORF or ThermoCam and the other end to the Ethernet switch port 1 if ThermoCam port 2 if ORF Connect one end of another Ethernet cable to port 5 and the other end to a computer Turn on the Ethernet switch An LED indicator light should turn on Turn Halo on Switch on MICPCB Verify successful data streaming a Forthe ThermoCam The ThermoCam GUI on the computer is receiving images sent by the ThermoCam b Forthe ORF The ORF is sending images and those images can be displayed on the computer Terminate data streaming from the sensor using the laptop terminal Switch off MICPCB Turn Halo off Turn off Ethernet switch 0 Disconnect Ethernet cable from computer cO ON a OMND May 15 2014 16 831 SPHERES INSPECT Design Document 115 The Ethernet swtich will then be directly connected to the VERTIGO Avionics stack to continue to test the MICPCB VERTIGO sensor interface with regards to data Continued immediately from the previous test this test will be carried out in the following steps 1 e 8 9 10 11 12 13 14 15 16 Connect the Ethernet cable from port 5 on the switch to the Ethernet port on the VERTIGO Avionics Stack Connect the Avionics Stack to the computer via the VERTIGO dongle Turn on the Ethernet switch Verify that the LED indicator light is on Turn on the VERTIGO Avionics Stack Push the red reset button on t
77. eads Current 0A Voltage 11 1V 3 Turn on MICPCB 4 Usethe multimeter to check the following quantities a Voltage across the two ends of the resistor output voltage 12V b Input voltage remains 11 1V c Assuming the voltage regulator is 75 90 efficient as given in the data sheet for voltage regulator Delta S24SE12002PDFA DC DC input current as read from the power supply is 0 8 1 0A Output current current through the resistor is approximately 0 74A These current values depend on using a 150 resistor load if other resistors with differing resistances are used expected current input and outputs should be calculated Once these steps have been completed and the MICPCB has been verified to work as expected the legs of the voltage regulator and Ethernet port need to be trimmed with wire cutters and filed down for the MICPCB to fit inside the mount structures In addition either the 50 pin connector side of the board or the adjacent side of the mount structure back plate needs to be covered with protective kapton tape to ensure that the MICPCB does not short against the aluminum plate CL Imaging Sensor Software Integration and Testing HS For all three imaging sensors ORF VERTIGO and ThermoCam software development and implementation is required to ensure proper communication with the VERTIGO Avionics Stack The objective is to obtain images from all these sensors and store them in a format accessible by OpenC
78. ed facing the positive X direction and three in the negative X direction although four two on each side are angled in the positive or negative Z direction by 45 degrees See Figure 30 for visual representation 4 4 Thermal Considerations HM MK NC 4 4 1 Overview MK HM The thermal analysis below was conducted to validate the health and safety of INSPECT subsystems over the length of mission operations The primary concern was overheating of components primarily the Optical Rangefinder ORF and Thermographic Camera ThermoCam above maximum operational temperatures prior to meeting the required 30 minutes of operation time The maximum operating temperatures for the components of interest are detailed in Table 35 Note that the upper and lower operating temperature bounds are similar for all systems with greater variation in survival bounds Table 35 Thermal Ranges May 15 2014 16 831 SPHERES INSPECT Design Document 95 Min Operating Max Operating Min Survival Max Survival Component Temp K Temp K Temp K Temp K MESA SR4000 ORF 283 323 263 343 FLIR A5 ThermoCam 288 323 133 343 HoneyBee CMG 288 323 253 358 VERTIGO Electronics 288 333 263 343 4 4 2 4 4 3 May 15 2014 Assumptions HM updated by MK In order to perform the thermal analysis of INSPECT the following assumptions were made about the thermal characteristics of system 10096 of power drawn by each system is con
79. ery packs Replace Halo and VERTIGO battery packs with freshly charged packs Power INSPECT system on Establish communication between SPHERES VERTIGO and Halo systems Run BlobTrack for at least 30 minutes at frequency of 0 5 Hz on solely battery power a Record elapsed time until low battery warning shows on VERTIGO Avionics Stack and or on the SPHERES Quit BlobTrack test program Power INSPECT system off Power INSPECT on retrieve battery and data usage log files from VERTIGO using USB key if necessary power off INSPECT a More detailed explanation of batter usage data retrieval in VERTIGO preliminary test plan document Tasks to be completed prior to termination of testing e SPHERES Halo and VERTIGO should be properly stored after use e Batteries shall be removed and recharged for future testing e Calculation of INSPECT power will be derived from the battery data from VERTIGO or observed from the DC Power Source Test Results The results will be used to verify the various criteria from Section 3 The power draw requirements and usage S 3 and I 1 will be determined by examining the battery log files The data communication and processing criteria will also be evaluated in compliance with H 2 and l 8 respectively Testing Results Table Criteria Test Result Pass Y N S 3 Measure power draw from SPHERES using DC power source and power draw from VERTIGO using battery log files The total power draw must
80. es AL The VERTIGO system requires no additional structural components to be assembled in order to be incorporated into INSPECT The Halo system fully supports integration of the VERTIGO system during operation 4 1 2 5 Mass JB AL HS The mass characteristics of the VERTIGO system are listed below in Table 9 VERTIGO Component Masses Table 9 VERTIGO Component Masses Mass Budget 1 8kg Item Mass kg Notes Avionics Stack 0 82 Optics Mount 0 73 Nikon EN EL4 Battery 0 162 Total Spent 1 732 Budget Remaining 3 796 4 1 2 6 Power and Interfaces JB AL HS Table 10 VERTIGO Peak Power Budget Peak Power Budget 16 5W Item Power W Notes Optics Mount 1 3 For 2 cameras Avionics Stack 6 8 Total Spent 8 1 Budget Remaining 50 996 Table 11 VERTIGO Average Power Budget Average Power Budget 5 SW gt O O Item Power W Notes Optics Mount 0 575 Avionics Stack 6 8 Total Spent 7 95 Budget Remaining 4 1 2 7 Data and Interfaces JB AL Table 12 VERTIGO Data Rate Budget Data Rate Budget 320Mbps Rate Mbps Notes Total Spent 10 8288 Budget Remaining 96 6 Table 13 VERTIGO Data Rate Budget Data Processing Budget 300ms Time ms Notes May 15 2014 16 831 SPHERES INSPECT Design Document 53 Total Spent Budget Remaining 4 1 2 8 Software HL The VERTIGO soft
81. es JS JK MA The CMG subsystem requires 12V for normal operations It receives power directly from Halo via the 50 pin Samtec connector which provides 11 1V at 1 5A The flow of power is as follows 50 pin connector gt CMG PCB gt CMG Control Box gt 20 pin micro d x 4 gt CMGs x 4 The different states of the CMG payload will determine its power requirements at any given time While spin up of the flywheel was thought to require the most power this is only the case if the gimbal motor is enabled Otherwise max power draw occurs when the CMGs are at max flywheel rate 6000 RPM and max gimbal rate 60 deg s Spin up occurs only once per normal operation Therefore the potential for an over maximum power draw can be eliminated with a sequential spin up of each CMG with all gimbal motors disabled Spin up power draw under nominal conditions is higher than Halo allows however two strategies can be used to bring that rate down to acceptable levels First the CMGs may be spun up sequentially instead of simultaneously meaning that only one CMG is spinning up at a time Second each CMG can vary the rate at which it is spun up decreasing that rate will proportionally increase the amount of time each spin up takes Using this strategy power draw at spin up can be lowered to acceptable levels If spun up sequentially the CMGs will not cancel each other s angular momentum thus the system must be physically secured during spin up Steady state
82. essure to 35 psi Set the air carriage pressure to 95 psi Run code to complete Conops maneuvers see INSPECT Integrated Test Report 3 Timeline Summary This test was conducted in several increments The first took place at approximately 1300 to 1500 on May 9 2014 The second was from 1300 to 1900 on May 10 2014 The table below shows a summary of the tests run Session 1 6 2 7 9 Test Results 1 General ISS 4 was verified by measuring the volume of the system INSPECT is 0 575m by 0 470m by 0 630m which is well within the volume of the airlock it is expected to fit through Test T1 T2 T3 T4 T5 T1 T3 T4 T5 T6 Description SPHERE Checkout Air Carriage Checkout Integrated Test Cycle 1 Cycle 1 Adjustments Integrated Test Cycle 2 Replaces Batteries Replaced Air Tanks Cycle 2 Adjustments Integrated Test Cycle 3 Cycle 3 Adjustments System Disassembly SPHERE Checkout Air Carriage Checkout Integrated Test Cycle 4 Cycle 4 Adjustments Integrated Test Cycle 5 Replaced Batteries Replaced Air Tanks Cycle 5 Adjustments Integrated Test Cycle 6 Cycle 6 Adjustments Integrated Test Cycle 7 Cycle 7 Adjustments System Disassembly Start Time 1330 1332 1334 1339 1359 1403 1408 1414 1439 1444 1450 1330 1332 1334 1339 1439 1444 1445 1451 1606 1611 1656 1701 1731 Interval 0 02 0 02 0 05 0 20 0 05 0 05 0 06 0 25 0 05 0 06 0 10 0 02 0 02 0 05 1 00 0 05 0 05 0 06 1
83. ette tenens 104 6 2 4 CMG Single Component Testing Structures 106 6 2 5 MICPCB Integration Tests CL CK KAF 111 6 2 6 CMG Full Assembly Stack Testing Capability JS 117 6 2 7 System Level Tests GK arron r a t e TI Ee ON TNR ege 117 7 Conclusion MC HS MK icio Ee entente 128 8 Acknowledgements icici sce scnssisnd eeh eg a pna rincer or ao kk Reik See deed resini 128 C WEN E err rcr eT TP 129 10 Appendix A Contact Information e ecce eese eee eene eene enne nne nn nnne nenne nnn 131 11 Appendix B Subsystem Tradespaces eeeeeeee esee eene eene eene enne enne nennen nnn 132 11 1 Optical Rangefinder MV siens iue EE deed einen exorto dd su Gu pao nno Load Ta e o rao vo es 132 11 2 Thermographic Camera TW ssssccssssssssssssssecsccccscsssssseeceeseccnacssssseseesesecansssseesessessoanagss 134 11 3 ADCS 1 E EAEE nd d hh EE 135 12 Appendb CIKED e uit tie 137 12 3 R dio GPS EE 137 12 1 1 Purpose and Relevance to INSPECT GP 137 12 1 2 Requirements Satisfied GP iii 137 12 13 cDrade Study a4 a t DER RR 137 12 1 4 Decision Made GP iii 138 12 15 INCORPORATION GP A eier Scheuer rte tege eet inae tete osent Seen Ze 138 12 2 Hazcams HS KH A 1 2 eta Erie een tente nn pase aae En aL be pe paso Ver ed aoa OE REPE Eu ed Fa AED SER et es el Esa oae 139 12 2 1 Purpose and Relevance to INSPECT iii 139 12 2 2 Requiremerits Satisfled eroe ete HER
84. f the same capabilities of SPHERES X but with the ability to be integrated with a number of space vehicles 2 2 INSPECT Mission and Systems Requirements JW JB MC Verification ID Name Requirement Parent Rationale Method Mission Statement The mission of INSPECT is to prototype and test a sensor actuator suite to facilitate NASA Human Exploration and Operations Mission Directorate HEOMD MS INSPECT mission need for free flying autonomous systems for extravehicular inspection and 1 Mission characterization Mission Level Requirements The INSPECT sensor actuator These operational suite shall be designed as a modes correspond to prototype payload for potential SPHERES to test specific extravehicular operational modes inside the functions for systems M 1 Prototype ISS MS 1 such as SPHERES X Analysis INSPECT shall reduce risks associated with the new Opportunity for design sensor actuator system by iteration prior to Risk using SPHERES testing moving outside of the M 2 Reduction capability inside the ISS MS 1 ISS Analysis ISS Requirements Remove risk of entering a region of space from which the The system shall remain inside system cannot be a predetermined operational recovered and to stay volume of the JEM 4 2 m within range of the ISS Test Space diameter 11 2 m length for communication 1 Limitations inside ISS operations M 2 system Inspection Ve
85. f the suite contains a laser it shall meet ANZI Z136 1 2000 for Class 1 2 or 3a lasers power measured at ISS Safety SAF 8 Lasers the source or SSP 50094 ISS 5 Requirement Inspection Verification Verified ORF light source is a Class 1 laser and meets specified requirements The suite shall provide covers for mechanical parts which pose a danger if Protective touched but may not ISS Safety SAF 9 Covers provide shatter resistance ISS 5 Requirement Inspection Verification Verified CMG Enclosures manufactured and inspected to confirm The suite s surface and SAF packaging shall be ISS Safety 10 Cleanliness disinfected prior to launch ISS 5 Requirement Inspection Unverified System has ability to be easily cleaned but no packaging has been designed Verification or manufactured This is scheduled for Summer 2014 The suite shall not contain SAF Harmful any biological substances ISS Safety 11 substances toxic substances or alcohol ISS 5 Requirement Inspection Verification Verified No known harmful substances are present on the system SAF The suite shall not contain ISS Safety 12 Pyrotechnics pyrotechnics ISS 5 Requirement Inspection Verification Verified No component contains pyrotechnics SAF The suite shall not contain ISS Safety 13 Cryogenics any cryogenics ISS 5 Requirement Inspection Verification Verified No component contains cryogenics The suite shall not contain any hardware that create a SAF Appendage potent
86. for docking purposes 3 Navigating SPHERES INSPECT through an environment without the SPHERES Metrology system using a Simultaneous Localization and Mapping SLAM algorithm May 15 2014 16 831 SPHERES INSPECT Design Document 55 Table 15 Optical Rangefinder driving requirements All imaging sensors shall Expectation of 30 have a minimum field of degree rotation per view of 33 degrees by 33 SX 1 image sequence with SEN 1 Field of View degrees SX 2 10 overlap Testing The system shall determine the distance to a target object accurate to within 10 Target cm with precision to 2 cm SX 1 SEN 2 Distance up to 7 meters away SX 2 Defines ranging limits Testing The system shall resolve a visible light image of a 1cm Visible Light per pixel resolution from 1 SX 1 Defines optical SEN 3 Image m SX 2 resolution limits Testing All sensors shall send data at a rate which can be processed by the VERTIGO computer or must include its own computer for data SEN 4 Sensor Data processing SX 4 Need to transfer data Testing The system shall resolve a thermal image of a 5x5 cm object from a distance of 1 Defines thermal m to 5 degrees C resolution limits and accuracy and a noise accuracy precision to equivalence temperature produce a reasonable Thermal difference of 1 degree C SX 1 thermal image for our SEN 5 Image at 20 degrees C SX 2 purposes Testing The system shall be able to Ability
87. gh the propulsions deck and 3 puck air carriage May 15 2014 16 831 SPHERES INSPECT Design Document 120 SLOSH Inspired CMG Clamp Cradle Supports Peripheral Mount Supports Propulsion Deck 3 Puck AirCarriage Figure 96 Full System Testing Structure Figure 97 Fully Integrated Testing Assembly May 15 2014 16 831 SPHERES INSPECT Design Document 121 6 2 7 6 2 Center of Mass and Volumetric Analysis The total mass of the system as we currently estimate will be 26 2kg Using solid works mass analysis tools we determine the center of mass COM to be displaced from the center of SPHERES by x y z 18mm 41mm 4mm These coordinates correspond with our expected center of mass as it is pulled back towards the heavier CMG subsystem and down towards our testing structure Inertia about the center of mass is approximately 59kg m to be verified in lab Using the parallel axis theorem we then determined the moment of inertia about the center of SPHERES to be 1 849kg m Figure 98 Fully Integrated Testing Structure COM The volume of our full system is 575mm x 470mm x 630mm or 170257 5 cm as seen in Figure 99 and Figure 100 Given the need to transport INSPECT along with its testing structure we can cut down the volume further by reorienting individual parts after partial disassembly May 15 2014 16 831 SPHERES INSPECT Design Document 122 May 15 2014 EE ea e le A Figure 100 Prof
88. gn Document 91 4 2 5 4 2 5 1 4 2 5 2 INSPECT Data Flow GP BC HS ETH Thermocam Russ Command Process VERTIGO USB x2 E Optics x2 USB CMG x2 lud Display UART SPHERES lus ut eid Avionics Stack SATA ETH Driver Display Transmit Receive Figure 74 INSPECT Data Processing Flow HS Overview and Desired Functionality GP HS In order to fulfill the goals of Navigation and Inspection INSPECT should provide a platform for software and algorithm augmentations to SPHERES The goal is to augment the current capabilities of SHPERES to incorporate the new sensor information available from additional hardware INSPECT will be able to obtain sensor information from the new hardware and store it in the VERTIGO Avionics Stack s hard drive Timing Analysis HS A worst case timing analysis was performed to ensure that the INSPECT system is capable of handling the data provided by its sensors For this analysis the typical 1Hz localization thrusting cycle for SPHERES was adopted as the time limit that the sensors had to meet In order to meet the minimum operational requirements each imaging sensor had to expose its CCDs read off their values download them internally and then transfer them over to the VERTIGO Avionics Stack Since the Avionics Stack handles these operations independently of SPHERES the thrusting and CMG control portion was excluded from the analysis The e
89. gulator and the SS 7188V A NF 8 pin Ethernet connector both had reliable data sheets so ther respective CAD libraries were created from the data sheet specifications The 1771101PHEONIX screw terminal did not have a reliable data sheet so measurements were taken in the lab in order to present a footprint of the screw terminal in Eagle CAD All of these components Eagle schematic and board layout representations can be seen in the below figures with the schematic symbol on the left of the figure and the layout footprint on the right of the figure These CAD libraries will be useful for further MICPCB development and testing as all three parts were essential and consistent during integration and testing Jg NAME VALUE Figure 116 Screw terminal used on the MIC PCB custom Eagle CAD 1771101PHEONIX CK G 1 ON OFF VOUT Figure 117 Voltage regulator used on the MIC PCB custom Eagle CAD S24SE12002PDFA CK May 15 2014 16 831 SPHERES INSPECT Design Document 151 NAME VALUE Figure 118 Ethernet connector used on the MIC PCB custom Eagle CAD SS 7188V A NF CK 13 3 CMG PCB Schematic Figure 119 Printed Circuit Board for the CMGs schematic NM GP CK May 15 2014 16 831 SPHERES INSPECT Design Document 152 14 Appendix E CAD Overview MK 14 1 Integrated Assembly There are several existing INSPECT system CAD assemblies each representing different layers of the SPHERES INSPECT platform Figure 120 pictures
90. h i For OFF position check pins 1 amp 2 are shorted together and are connected to ground For the MICPCBs the OFF position matches the position of the switch in the CAD outline printed on the surface of the board ii For ON position check pins 2 amp 3 are shorted together ON is opposite of the CAD outline of the switch printed on the surface of the board a 6 2 1 3 Single Component MICPCB Power Test Without Load CL CK After confirming that the MICPCBs are manufactured correctly and that all electrical connections are accurate a power test without a load in the circuit will be conducted to verify that the MIC PCB is capable of receiving an unregulated voltage of 11 1V and output a regulated 12V This test will be carried out in the following steps 1 2 May 15 2014 Ensure MICPCB switch is turned off Attach one stripped wire into the power terminal of the screw terminal and one into the ground terminal If a break out cable with a female 50 pin connector is available use that to connect to the male 50 pin connector Otherwise find pins surfaces on the MICPCB that connect to power Batt and ground Batt Batt was connected to pin 2 on the switch and Batt was connected to the Vin pin on the voltage regulator during testing 16 831 SPHERES INSPECT Design Document 102 4 Set power supply to 11 1V and then turn the power supply off 5 Connect power supply to Batt pins 7 9 11 and Batt pins 1 3 5 on the fe
91. he SPHERES satellite relative to the world frame in which the beacons are set 8 MV Time of flight range tien trasoun measurements WM Lo UE We beacons 200 150 3 n 100 bes po OV OM Satellite 200 iere 1 prt per r m p e zg S Sor E Ka 0 SE 250 x em E Figure 43 The SPHERES Metrology system uses time of flight measuements from ultrasound beacosn to the SPHERES satellite 9 The IR light emitted by the ORF triggers the IR receivers in the beacons and on the SPHERES 10 If the ORF is operated sporadically these IR pluses can cause the beacons to send out ultrasound responses which are out of sync with the Metrology system cycle These extraneous ultrasound pulses can cause erroneous distance readings which degrade the accuracy of the Metrology systems position and attitude determination The Metrology readings are passed through a nonlinear Kalman filter before being used to determine the satellite s pose so some level of noise in the readings can be tolerated 8 MV May 15 2014 16 831 SPHERES INSPECT Design Document 60 If the ORF is operated continuously and its light illuminates a SPHERES satellite for example if one SPHERES satellite equipped with INSPECT is scanning another SPHERES satellite the illuminated satellite can cease to function 10 The highest priority interrupt in the SPHERES Digital Signal Processor DSP software is the IR Rcv interrupt which is triggered
92. he Stack if necessary Verify that the CPU Power green indicator light is on and that the fan is turning Turn Halo on Switch on MICPCB Verify that the sensor either ThermoCam or ORF is being powered and that the appropriate data indicator lights on the sensor or on the Ethernet switch are on Verify that the laptop can receive data and view images sent by the ThermoCam ORF Terminate data streaming from the sensor using the laptop terminal Switch off MICPCB Turn Halo off Shutdown the VERTIGO Avionics Stack from the laptop interface Turn off the VERTIGO Avionics Stack Turn off the Ethernet switch Disconnect Ethernet cable from the switch to the VERTIGO Avionics Stack Disconnect VERTIGO dongle from the computer 6 2 5 4 MICPCB Halo Both Sensors and Ethernet Switch CL Verify that ThermoCam and ORF and their respective MICPCBs still function when both sensors are connected to Halo Repeat the second half of the test steps 1 15 In section O 6 2 5 5 MICPCB Halo a Single Sensor in Mount Structure and Ethernet Switch CL KAF Each MICPCB now will be attached to its respective mount structure that will house the ThermoCam and ORF to verify the continued functionality of the MICPCBs 1 2 3 4 5 6 T Attach the MICPCB to the back plate of the mount structure While still disconnected from any other electronics check that there are no electrical shorts between the pins and traces of the MICPCB and the al
93. header and pointer KH Drivers Custom Software commands n Be Code keyboard Metrology data SPHERES Controller I Figure 45 Software Interface Diagram 4 1 3 7 Mass MV The MESA SR4000 has a mass of 0 510 kg With mounting and interface devices the total mass of the Optical Rangefinder subsystem on the Halo port will be 0 828 kg Table 18 Optical Rangefinder Mass Breakdown MV CK Mass Budget 1 8 kg Item Mass kg Notes MESA SR400 0 510 The ORF Measured Mount 0 278 Structural Mount for ORF Measured MIC PCB Board 0 020 Approximate mass of finalized PCB Estimate Wiring 0 020 Approximate mass of all wiring to Halo PCB Estimate Total Spent 0 828 Budget Remaining 54 00 4 1 3 8 Financial Budget The allotted budget was intended for spending on the chosen ORF PCBs and populating components wiring and structural connections The largest percent of the budget was spent on the actual sensor which at 4 065 05 made up 60 22 of the allotted budget Other expenses included an appropriate power supply connectors PCBs and components to test and then populate the PCBs CK Table 19 Optical Rangefinder Financial Budget MV CK KH Budgeted 6 750 Item Cost USD Notes ORF Power Supply 39 78 Power Supply for ORF from DigiKey ORF Power Connector 24 38 Power Supply Connector for ORF May 15 2014 16 831 S
94. ht per pixel resolution from 1 SX 1 Defines optical SEN 3 Image m SX 2 resolution limits Testing All sensors shall send data at a rate which can be processed by the VERTIGO computer or must include its own computer for data SEN 4 Sensor Data processing SX 4 Need to transfer data Testing The system shall resolve a thermal image of a 5x5 cm object from a distance of 1 Defines thermal m to 5 degrees C resolution limits and accuracy and a noise accuracy precision to equivalence temperature produce a reasonable Thermal difference of 1 degree C SX 1 thermal image for our SEN 5 Image at 20 degrees C SX 2 purposes Testing The system shall be able to Ability to support guest determine its pose in 2 scientist navigation dimensional space with 1 SX 1 algorithms Pose axis of rotation normal to SX 2 necessitates SEN 6 Sensors the test floor SX 5 navigational sensors Testing 4 1 2 3 Design Choice AL May 15 The VERTIGO system was selected for use in INSPECT for its ability to serve both as a peripheral sensory system Optics Mount and the ability to serve as the main processing platform for all of the peripheral systems Avionics Stack It has already been test and verified to function effectively with the SPHERES platform which means that it would expectantly require less initial development to become compatible with INSPECT than another brand new system 2014 16 831 SPHERES INSPECT Design Document 52 4 1 2 4 Structur
95. ht Ethernet pins must be connected even if only four are used for data transmission as is the case with the ORF As of May 2014 Halo does not have working data connection in any of the ports other than the HPG port that VERTIGO connects into so no data will be transferred via the Ethernet pins on the MICPCB Instead both the ORF and the ThermoCam will transmit data through a central Ethernet switch that is connected to the VERTIGO Avionics Stack More detail on this configuration is detailed in Section 6 2 5 The intent is to use the same Ethernet connector on the current MICPCBs in the future to route data through the MICPCB after testing has been completed CL CK Health monitoring is performed via a polymeric positive temperature coefficient device PPTC resettable fuse for the power loop Two lines run parallel to the main load connected by the fuse An LED separate from and colored differently from the power on LED in this case colored red is connected to the loop which does not depend on the fuse for power and will remain unlit until the fuse is blown at which time it will light up and display a warning that the sensor has failed and is no longer connected to power The second parallel loop keeps the LED un lit during normal operation by means of a diode to the base of the type P N P binary transistor which straddles the two parallel loops In order to resume functionality all power must be cut and reset to the system by turning the H
96. ial appendage ISS Safety 14 Entrapment entrapment ISS 5 Requirement Inspection Verified All components designed for flush connections to prevent appendage Verification entrapment SAF The suite shall not contain ISS Safety 15 Sharp Edges any sharp edges ISS 5 Requirement Inspection Verification Verified All components verified to have no sharp edges to touch The suite shall not contain SAF any hardware that could ISS Safety 16 Pinch Points create a pinch point ISS 5 Requirement Inspection Verified All components verified to have no pinch points or are enclosed to avoid pinch Verification points All imaging sensors shall Expectation of 30 have a minimum field of degree rotation per view of 33 degrees by 33 SX 1 image sequence with SEN 1 Field of View degrees SX 2 10 overlap Testing Verified All sensors meet requirement limiting sensor ThermoCam with 44 x 36 Verification degrees SEN 2 Target The system shall determine SX 1 Defines ranging limits Testing May 15 2014 16 831 SPHERES INSPECT Design Document 19 Distance the distance to a target SX 2 object accurate to within 10 cm with precision to 2 cm up to 10 meters away Verification Verified ORF and VERTIGO independently meet requirement The system shall resolve a visible light image of a 1cm Visible Light per pixel resolution from 1 SX 1 Defines optical SEN 3 Image m SX 2 resolution limits Testing Verification Verified VERTIGO has 4 pixels per 1cm x 1c
97. ide power to all Halo ports 4 Measure input and output voltages on MICPCB 0 V for both measurements 5 Switch on MICPCB 6 Measure input and output voltage on MICPCB approximately 11 1 V and 12 V respectively as shown in Figure 90 7 Switch off MICPCB 8 Turn Halo off Figure 89 MICPCB and Halo setup CL May 15 2014 16 831 SPHERES INSPECT Design Document 112 Figure 90 MIC PCB connected to Halo verifying 12 V output from PCB CL 6 2 5 2 MICPCB Halo and a Single Sensor CL KAF After verifying the appropriate voltage input to and output from the MICPCB via Halo a single sensor either the ORF or the ThermoCam is connected to its respective MICPCB and corresponding Halo port to test if the board is able to power the sensor using Halo power 1 Connect the sensor to the MICPCB via the screw terminal a Forthe ThermoCam Connect the M12 end connector to the ThermoCam and connect the power and ground wires to the appropriate terminals on the screw terminal b Forthe ORF Connect the M3 connector to the ORF and connect the power and ground wires to the appropriate terminals on the screw terminal 2 Turn Halo on Switch on MICPCB 4 Check that the sensor has been powered on a Forthe ThermoCam It will click twice for its initial calibration and the blue indicator light on its rear face will be on as shown in Figure 91 b Forthe ORF The ring of red LEDs on its front face will be on and the green indicator ligh
98. ign Document 134 FLIR A5 Each item is rated on a scale of 1 5 for each category which is then multiplied by the weighting factor indicated in the header row and summed to determine a final score The FLIR A5 received the largest score by a 42 point lead 11 3 ADCS LJ The attitude determination and control system ADCS chosen was the Honeybee CMGs This decision was reached by comparing the actuators in Table 48 using the tradespace summarized in Table 49 Table 48 Actuator Candidate Specifications Actuator Actuator Type Mass Max Max Dimensions Average Max Cost kg Control Angular cm Power Power USD Moment Momentum w Needed N m N m s w Honeybee CMG 3 0 112 0 056 23x12 5x8 2 10 14 0 CMGs Maryland Reaction 0 64 0 000635 0 0011 8 1x8 1x6 9 4 7 2 12745 Aerospace Wheel RW 0 01 Reaction 0 12 0 01 0 01 5x5x3 0 16 0 7 20000 Wheel RW 0 03 Reaction 0 19 0 03 0 03 5x5x4 0 4 1 5 25000 Wheel RW 0 06 Reaction 0 23 0 06 0 06 7 5x6 5x3 8 0 5 7 35000 Wheel Clydespace Reaction 1 5 0 035 1 9 13 5x13 5x8 28 33000 Wheel 2 Clydespace 3x 0 15 3 42E 05 N A 10x10x 43 2 6 4800 Magnetorquer SSBV 3x 3 3 0 006 N A 20 each 3 3 4500 Magnetorquer 20 cm AraMiS Reaction 0 57 0 253 0 03519 Tiny 8 8 14000 ADCS Wheel Table 49 Attitude Control System Pugh Chart Mass Power Cost Control Authority Limitations Total 10 20 35 15 Multiplier
99. ile area in y z plane 16 831 SPHERES INSPECT Design Document 123 6 2 7 7 Requirement Verification Requirement ID Requirement Description ISS 1 The system shall remain inside a predetermined operational volume of the JEM 4 2 m diameter 11 2 m length for inside ISS operations ISS 4 The fully integrated system shall be capable of fitting in the 57 6 x 83 x 80 cm JEM airlock S 1 The system shall allow for stored information to be transferred to a host computer H 1 Each suite component shall connect to Halo using the 4 hole square screw pattern H 2 Each suite component shall be able to connect to the Halo via USB 2 0 or Ethernet l 7 The sensors shall point in the same direction and be placed no more than 50cm apart SEN 1 All imaging sensors shall have a minimum field of view of 33 degrees SEN 2 The system shall determine the distance to a target object accurate to within 10 cm with precision to 2 cm up to 10 meters away SEN 3 The system shall resolve a visible light image of a 1cm per pixel image from 1 meter SEN 4 The system shall resolve a thermal image of a 5x5 cm object from a distance of 1 meter to a 5 degree C accuracy and a noise equivalence temperature difference of 1 degree C at 20 degrees C 6 2 7 8 SEN 6 The system shall be able to determine its pose in 2 dimensional space within 1 cm and 0 5 degrees with 1 axis of rotation normal to the test
100. is when the gimbal rates are zero while peak is when gimbal rates are at their maximum Table 27 CMG Peak Power Breakdown Peak Power Budget W Item Power W Notes CMG 9 Occurs when all four CMGs at maximum torque Regulator 3 Total Spent 12 Budget Remaining 4 65 Table 28 CMG Average Power Breakdown Average Power Budget W Item Power W Notes CMG 5 7 Regulator 3 Total Spent 8 7 Budget Remaining 1 7 Table 29 CMG power requirements 14 Item and State Power Required 4xCMGs Drive Electronics Steady 7 watts 4xCMGs Drive Electronics Peak 11 watts 4xCMGs Drive Electronics Spin Up 14 watts May 15 2014 16 831 SPHERES INSPECT Design Document 81 4 1 5 5 Data and Interfaces NM The CMG controller will interface with the 50 pin Samtec connector that is propagated to all of the Halo ports The Honeybee control assembly attaches to one port and interfaces directly with four Honeybee LEO CMGs The LEO model requires RS 422 input which is not available on the Samtec connector In order to transfer data to and from the LEO model controller an interface PCB is required to convert the USB signal to RS 422 A diagram depicting the overall data flow is shown below SAMTEC Connector CMG Interface E 9 g S e KL a KN GG CMG Controller Figure 66 CMG PCB Board Flow Diagram NM May 15 2014 16 831 SPHER
101. isting specifications of the following systems 2 International Space Station ISS and Lab safety SPHERES VERTIGO Halo Qgyum ES 15 3 Development Requirements Development requirements outline how 16 83x INSPECT plans to achieve the mission requirements while under the constraints of the other systems 15 3 1 SPHERES X Requirements SPHERES X requirements are meant to show traceability to the eventual goal of EVA missions 15 3 2 INSPECT Suite Requirements INSPECT requirements flow from SPHERES X requirements and place limitations on how our suite shall perform the traceable functions outlined in the SPHERES X requirements It should be noted that not all SPHERES X EVA requirements will be pursued by 16 83x INSPECT Certain EVA requirements such as radiation hardening and the ability to survive extreme thermal gradients are not in scope for ground testing 15 3 3 Sensing Requirements Sensing requirements outline the specifications of the sensors for the INSPECT suite 15 3 4 Control and Actuation Requirements Control and actuation requirements define how SPHERES INSPECT will change the pose of the system though space This includes overall system movement as well as controls required for proper sensing May 15 2014 16 831 SPHERES INSPECT Design Document 158 Mission Statement CONSTRAINTS DEVELOPMENT Mission Level SPHERES X SPHERES Filter HALO um Figure 131 Graphical interpretation of requirements f
102. ixers convert forces and torques into thruster on off times A separate mixer to convert torques into either gimbal rates was developed The torque values inputted from the CMG attitude controller are used to derive a necessary change in angular momentum about the y axis by the CMGs This change in angular momentum together with the current gimbal position of each CMG in radians can be used to calculate the necessary gimbal rate to result in the desired torque on the spacecraft These gimbal rates are then sent to the Honeybee CMG Controller out of the UART port on SPHERES Forces are still sent through the standard thruster mixer A Simulink model for the CMGs has been developed for use with the SPHERES simulation The model has been tested in the 3 deg of freedom case x and y axis translation and z axis rotation by 16 851 s CMG team Further development for software is necessary to extend the current systems to the 6 degrees of freedom case This will require modifications to the CMG mixer as well as the Simulink model May 15 2014 16 831 SPHERES INSPECT Design Document 84 4 1 5 7 PD and NLPD Gate ais L Conte cme Mixer Error Law c Thruster Asynch Receive Send CMG Mixer CMG Comm Comm U age Figure 69 Block diagram of software system for SPHERES and CMG Payload Onboard of SPHERES the control algorithm collects the current state vector from the IMU and uses it to calculate the current error from the target state Wi
103. ks but must also be able to process received data and still maintain control authority over SPHERES Stack Testing serves to simulate full INSPECT functionality on a preliminary level Systems will still communicate through the Samtec 50 pin connector on the Avionics Stack that they will interface with when connected to Halo After sensors have been individually verified with VERTIGO the MICPCBs will be tested and used as the interface between Halo and the sensors 6 2 3 2 Personnel During Stack Testing members of the VERTIGO Subsystem Team as well as members of the tested peripheral subsystem and members of the Avionics subsystem must be present Systems Integration and Systems Lead team members of the INSPECT team shall also be present 6 2 3 2 1 Core Personnel present during all subsystem stack testing VERTIGO Team e Alessandro Lira e Hang Woon Lee Avionics Team e Candice Kaplan e Connie Liu Systems Integration e Grace Krusell e John Wenzel Systems Leads e James Byrne e Melissa Kornspan May 15 2014 16 831 SPHERES INSPECT Design Document 104 6 2 3 2 2 Peripheral Systems Personnel present during relevant subsystem stack testing ORF Team e Matthew Vernacchia e Katherine Hobbs ThermoCam e Krystal Arroyo Flores e Alex Wassenberg CMGs e James Krasner e Matthew Abel 6 2 3 3 Location Individual Stack Testing will take place in the MIT Space Systems Laboratory in room 37 372 on the SSL Glass Table Figure 84 SSL
104. lation computer s hardware and the actual Avionics Stack processing power 4 1 2 10 Financial Budget AL VERTIGO was allotted 450 for use in the development INSPECT The VERTIGO budget is relatively small compared to the other subsystems due to the fact that the VERTIGO system is already whole and complete and needs very little additional hardware or software support which would require a larger budget The only expense during the development of INSPECT was the purchase of new SATA solid state hard drives to use for the VERTIGO Avionics Stack as main storage drives Two SATA drives were required but once purchased it was found that one was faulty A third drive purchased to replace the faulty drive Table 14 VERTIGO Financial Budget Financial Budget 450 Item Cost USD Notes 3 InnoLite SATADOM 175 x3 2 SATA drives needed a third was purchased to replace D150QV SATA drives a faulty original Total Spent 525 Budget Remaining 1796 4 1 3 Optical Rangefinder MV HS MK KH 4 1 3 1 Driving Requirements and Relevance to INSPECT The Optical Rangefinder ORF allows INSPECT to gather depth and near infrared 7900 nm images of its environment This data is relevant to a number of potential guest scientist missions such as 1 Scanning an object in order to generate a 3D model as a first step to inspecting that object 2 Estimating the pose of SPHERES INSPECT relative to another satellite
105. ll sensors to have a blur sufficiently isolated coefficient of less than or from vibration in order Sensor equal to 1 Blur coefficient to prevent blurring of C 1 Stabilization tint Ores SEN 1 image data Testing System shall be able to translate in a controlled manner through three dimensional space in a Translation is microgravity environment to SX 1 necessary for C 2 Translation 1 cm accuracy SX 2 navigation Testing System shall be able to control its attitude through three dimensional space in Attitude control is a microgravity environment SX 1 necessary for C 3 Attitude to 0 5 degree accuracy SX 2 navigation Testing Sensor blur requirements during System shall be capable of inspection and achieving an angular SPHERES internal velocity below 0 58 rpm in gyroscopes during inspection mode and navigation limit Angular below 9 rpm in navigation SX 1 allowable angular C 4 Velocity mode SX 2 velocity Testing Need to know when CMGs are The system shall be able to approaching track saturation levels at all saturation to maintain C 5 Saturation times SX 1 command authority Testing The actuators shall provide Some sensors may Sensor movement for sensors that require increased field A 1 Movement require motor functions C 1 of measurement Inspection The system shall be capable of producing a torque of at least 11x10 3 Based on SPHERES Testing and A 2 Torque Nm C 4 torque capability Analysis The system shall be Linear capa
106. lo facilitates a connection to the VERTIGO Avionics Box and DSP on the SPHERES internal CPU thereby giving INSPECT access to the VERTIGO software for processing guest scientist algorithms and commanding SPHERES Goggles User Code Goggles Network API GE Library Goggles SPHERES Goggles Optics API API UART TCP UDP USB Driver Linux RT Kernel 2 6 24 Figure 6 VERTIGO Avionics Software Architecture 6 4 1 1 8 Mass 4 1 1 9 The total Mass of Halo is 4 525kg including batteries 5 4 1 1 10 Financial Budget 4 1 2 4 1 2 1 The Halo will be considered a commercial off the shelf COTS product as all costs will be incurred by 2 Lt Bryan McCarthy s team and the MIT Space Systems Lab VERTIGO Goggles AL HL Description The VERTIGO Goggles are comprised of two pieces of hardware the Optics Mount and Avionics Stack that come together to make the system referred to as the VERTIGO Goggles 4 1 2 1 1 VERTIGO Avionics Stack The VERTIGO Avionics Stack is comprised of the tan colored square enclosure which houses VERTIGO s CPU hard drives operating system and wi fi network components It acts as the computer for the VERTIGO Goggles handling all of the image processing and sensor commands for the subsystem 6 It runs Linux Ubuntu 10 04 as its operating system In relation to INSPECT the Avionics Stack will handle inputs from all the peripheral systems in addition to the Goggles
107. low May 15 2014 16 831 SPHERES INSPECT Design Document 159
108. m but without any LED indicators due to an assembly error and in the interest of streamlining integration CK CL Power is routed from Halo over pins 1 3 5 7 9 and 11 on the Samtec 50 pin ERM8 025 09 0 S DV K TR male connector and into a Delta S24SE12002PDFA DC DC power regulator with 9 36V input 12V output and 20W rating Pins 1 3 and 5 serve as ground BATT on the 50 pin connector and pins 7 9 and 11 serve as power BATT that provide the 11 1V to power the MICPCB The voltage and current entering the voltage regulator is set at 11 1V and 1 5A and the regulator steps up the voltage to the 12V required by both the MESA SR4000 and the FLIR A5 Thermographic Camera The now regulated voltage from Halo is directly transmitted to the sensors via a 3 port screw terminal and a connection cable The ORF connects to this screw terminal via a Lumberg M8 3 pin cable and the ThermoCam connects via an M12 connector May 15 2014 16 831 SPHERES INSPECT Design Document 47 CK The wires for power shield and ground on each connector will connect to the appropriate ports on the screw terminal to power the sensors CL Data is routed into and out of the MICPCB via a Samtec ERM8 025 09 0 S DV K TR 50 pin male connector over pairs 45 amp 47 48 amp 50 42 amp 44 and 39 amp 41 to Ethernet pin pairs 4 amp 5 2 amp 1 8 amp 7 and 6 amp 3 for both the ORF and the ThermCam Because the board is intended for use by both sensors all eig
109. m square at 1m from target All sensors shall send data at a rate which can be processed by the VERTIGO computer or must include its own computer for data SEN 4 Sensor Data processing SX 4 Need to transfer data Testing Verified All sensors operate simultaneously and are limited by bandwidth of network Verification before VERTIGO The system shall resolve a thermal image of a 5x5 cm object from a distance of 1 Defines thermal m to 5 degrees C resolution limits and accuracy and a noise accuracy precision to equivalence temperature produce a reasonable Thermal difference of 1 degree C SX 1 thermal image for our SEN 5 Image at 20 degrees C SX 2 purposes Testing Verification Verified ThermoCam meets requirement within 2 5 degrees C The system shall be able to Ability to support guest determine its pose in 2 scientist navigation dimensional space with 1 SX 1 algorithms Pose axis of rotation normal to SX 2 necessitates SEN 6 Sensors the test floor SX 5 navigational sensors Testing Verified The design choice to use SPHERES as a platform inherently meets this Verification requirement The system shall stabilize Sensors must be all sensors to have a blur sufficiently isolated coefficient of less than or from vibration in order Sensor equal to 1 Blur coefficient to prevent blurring of C 1 Stabilization tint Ores SEN 1 image data Testing
110. maging sensors shall have a minimum field of view of 33 degrees The system shall determine the distance to a target object accurate to within 10 cm with precision to 2 cm up to 10 meters away The system shall resolve a visible light image of a 1cm per pixel image from 1 meter The system shall resolve a thermal image of a 5x5 cm object from a distance of 1 meter to a 5 degree C accuracy and a noise equivalence temperature difference of 1 degree C at 20 degrees C INSPECT shall provide a functional API for localization and mapping INSPECT shall provide a functional API for identification and description of observable objects INSPECT shall provide a means of assessing functionality of its components as a form of health monitoring INSPECT shall provide a functional API for the testing of future software INSPECT shall provide a platform for navigational algorithm development 16 831 SPHERES INSPECT Design Document 119 6 2 7 6 Full System Testing Structure and Peripheral Support JS Figure 95 shows our system as we envision it With our peripheral subsystems weighing in at 1 2 5 kg each INSPECT is a relatively bulky system Given that Halo was not designed to mount heavy subsystems in the presence of gravity the structures team was given the task of determining a structure that would fully support each peripheral constrain the CMGs in all 3 dimensions so that all torques imparted are absorbed through the propulsions deck and all
111. male 50 pin connector break out cable if used Otherwise connect the power supply to the same connections or pins that were probed in step 3 for power and ground pin 2 on the switch and the Vin pin on the voltage regulator respectively During testing the ground probe on the multimeter was connected to power supply s ground for ease of probing 6 Turn on the power supply Ensure that the power supply reads Current 0A Voltage 11 1V 7 Turn on MICPCB 8 Usethe multimeter to check the following quantities a Voltage across the two wires of the screw terminal the output voltage 12V b Input voltage remains 11 1V c Current reading on the power supply 0 05A 9 Turn off MICPCB 10 Turn off power supply 6 2 1 4 Single Component MICPCB Power Test With Load CL CK 6 2 2 After verifying that the MICPCB outputs 12V from an input of 11 1V a power resistor load will be connected to the MICPCB to simulate the ORF or ThermoCam before actually connecting the sensors to the board This test will be carried out in the following steps 1 Connect a 150 50W power resistor to the power and ground wires of the screw terminal During testing 11 10 15 20 and 250 resistors were used iterating through these next steps for each resistor If resistors with a resistance other than 15Q are used the current draw expected on the power supply should be calculated accordingly 2 Turn on the power supply Ensure that the power supply r
112. marily the ISS when a SPHERES is in a tightly confined area 12 3 2 Requirements Satisfied ID Requirement Parent Rationale Verification ISS 5 The system shall not be a hazard M 2 Safety is key for mission risk Testing on the ISS reduction H 2 Each suite component shall be able S 4 SPHERES will be utilized as Testing to connect to the Halo via USB 2 0 the foundation for the or Ethernet sensor actuator suite H 3 Each suite component shall S 4 Halo power settings Analysis operate on a 11 1 volt 5 amp power supply 12 3 3 Trade Study Shar Model USB ProxSonar Ez Sharp GP2YOA02 Ee SICK DL35 B15552 Optical Sensor A Optical Sensor Avg Power 0 015 W 0 165 W 0 150 W 1 7W Cost 50 15 27 need quote Mass 0 0049 kg 0 0048 kg 0 0050 kg 0 065 kg Volume 0 610 x 0 863 x 1 16 x 0 51 x 2 28 x 0 67 x 0 89 1 68 x 2 80 x 0 888 0 85 1 26 Min Range e 8 40 8 Max Range 125 60 216 1400 Response Time 38 10 ms 17 4ms 1ms Interface USB 3 pin JST 5 pin JST 5 pin M12 12 3 4 Decision Made The decision was made to not include proximity sensors because the updated requirements only specify that the front of the SPHERES should maintain a minimum distance from all obstacles Both the VERTIGO Optics Mount and the Optical Rangefinder ORF are able to be used to meet this requirement thus proximity sensors will not be used May 15 2014 16 831 S
113. meter thermal imager The FLIR A5 was chosen for its low volume and mass of 186 8 cm and 0 2 kg respectively This small size and mass make it ideal for inclusion on INSPECT Additionally the FLIR A5 was available to the team at a price of 2205 and the 5 mm lens version provides a large field of view of 44 x 36 horizontal by vertical full cone measurements The FLIR A5 has a Power over Ethernet PoE connection that is capable of transmitting and receiving data as well as power over the same port 12 For INSPECT however the PoE connection is not used as the FLIR A5 s use of Gigabit Ethernet necessitates the use of the Ethernet port exclusively for data transfer The ThermoCam system will instead make use of the round M12 connector visible in Figure 51 below to provide power from the Halo port 5 to the FLIR A5 The full tradespace and tradespace analysis charts can be found in Appendix B section 11 2 Figure 51 FLIR A5 Thermographic Camera 12 Mounting Structure NC KAF Mounts were designed for both the MESA SR4000 and the FLIR A5 The mounts were designed to use the same components so that spare parts could easily be manufactured to fit either one although the ThermoCam mount was later redesigned to extend out for an additional 1 cm The decision to extend the mount was made in order to completely house the ThermoCam s lense within the mount structure and to provide ample room at the rear of the camera to comfortably insert the M
114. mmunication Chief Engineer Melissa VERTIGO Alessandro Thermo Cam Krystal Avionics Nathan M Software MattA Avionics V Connie Software l Alex Structures Nathan C Subsystems Engineering Figure 2 Team Organization Structure JB Avionics Candice Software Hang Woon Software Katherine Structures Free Joel 2 Mission Overview 2 1 Context JW Systems Lead Mic Testing John Testing Grace Avionics George Software Hosea Systems Engineering INSPECT 16 83x is the first of four steps towards satisfying NASA HEOMD s goal of a free flying autonomous systems for extravehicular inspection and characterization pn zm zm zm zm zm zm zm zm zm Figure 3 HEOMD Mission Flow Step 1 INSPECT 16 83x is meant to provide a working test platform for ground testing that can later be to developed into a prototype to be flown on the International Space Station Step 2 INSPECT on the ISS is meant to be a fully functioning inspection probe to be used inside the International Space Station that can be matured into a design that can used for ISS EVA testing May 15 2014 16 831 SPHERES INSPECT Design Document 14 Step 3 SPHERES X is the name temporarily assigned to the future inspection probe that is capable of working in the space environment It is to be fully integrated with the International Space Station Step 4 The final HEOMD Mission is to be o
115. moCam with Halo Port 5 Table 24 Thermographic Camera Mass Breakdown Mass Budget 0 9kg Item Mass kg Notes FLIR A5 0 188 From Acceptance Test Mount MICPCB amp power 0 390 Measurement cable Ethernet cabe 0 088 Meaurement Total Spent 0 666 Budget Remaining 74 00 4 1 4 8 Financial Budget KAF CL The financial budget for the ThermoCam system is outlined below in Table 25 The PCB components and MICPCB orders were combined orders for both the ThermoCam and ORF subsystems the costs listed in the table are half of the total orders Table 25 Thermographic Camera Financial Budget Financial Budget 4050 Item Cost USD Notes FLIR A5 2300 From FLIR Systems Inc PCB Components 1 66 69 From DigiKey PCB Components 2 42 465 From DigiKey May 15 2014 16 831 SPHERES INSPECT Design Document PCB Components 3 135 835 From DigiKey PCB Switches 43 75 From Mouser M12 Pigtail 138 00 From Omega Inc MICPCB Iteration 1 48 61 From Advanced Circuits MICPCB Iteration 2 136 245 From Advanced Circuits M12 Connector end 30 91 From DigiKey Total Spent 2942 505 Budget Remaining 72 65 4 1 5 ACDS CMGs RN JK MK JS NM HS Driving Requirements and Relevance to INSPECT RN updated by Jk 4 1 5 1 Table 26 ADCS Driving Requirements The system shall stabilize Sensors must be a
116. n ORF Mount NC Temp Kelvin 3 053e 002 3 047e 002 3 042e 002 3 036e 002 3 031e 002 3 025e 002 3 020e 002 3 01 4e 002 3 009e 002 3 003e 002 2 998e 002 2 992e 002 2 987e 002 5 Risks and Mitigations tigat Expected risks for each subsystem as well as the fully integrated system are outlined in this section along with mitigations taken to minimize the likelihood and or impact of these risks 5 4 VERTIGO Goggles HL Table 37 VERTIGO Goggles Risks and Mitigations A VERTIGO Avionics Stack boot and storage Failed boot and storage drives can be always drives are not properly installed reinstalled Most of system crashes occur as a software crash VERTIGO system crashes during software The operating system can be reinstalled and thus development reducing the impact However there are possibilities of loss of software programs operating on VERTIGO Goggles parameter file Users can lower down the FPS Dres all eiie E from peripherals into a 5D voxel and align data but to output gathered sensor data May 15 2014 16 831 SPHERES INSPECT Design Document 97 Likelihood Figure 79 VERTIGO Goggles Risk Fever Chart 5 2 Optical Rangefinder ORF MV Table 38 Optical Rangefinder Risks and Mitigations Testing shows that operating the ORF at 1 image per A ORF interferes with US IR Metrology second increases the error in the metrology system to less that 15096 of its original value A voltage regulator o
117. n imaging 2m IN P D Ke Figure 17 Maneuver 7 Maneuver 8 Rotational Deceleration LA 1m P e t Figure 18 Maneuver 8 May 15 2014 16 831 SPHERES INSPECT Design Document 30 2 3 2 3 Inspection Maneuver Calculated Results The complete inspection procedure has been modeled to allow for correct acceleration planning as well as the ability to compare real system functions to idealized maneuvers The entire inspection maneuver shall consist of eight total images and take about 188 5 seconds to complete Position Velocity x 10 Acceration 3 5 0 1 2 3 1 25 0 05 e T C E 0 iH E T S ZS 0 ZS 15 9 E S E 8 2 0 05 S 0 5 3 0 0 1 4 0 100 200 0 100 200 0 100 200 time s time s time s Attitude Angular Velocity Angular Acceration 3 5 0 4 cc 031 N 3 2 03 7 S 0 05 S E E 9 2 5 0 2 5 E 5 E 0 c I 2 9 oi Ee 5 8 amp S 0 05 1 5 gt 0 s i 2 bal 1 0 1 0 1 0 100 200 0 100 200 0 100 200 time s time s time s Figure 19 Modeled Inspections 2 3 3 Contingency Operations JW Sensor Operation Termination Sensor termination will be implemented in situations where non nominal current flow occurs for a given sensor If excess current or no current is flowed to a sensor all current to the sensor will stop Manual System Operations Termination Manual system termination
118. n shows to be within 0 25 and 0 35 which is within precision limits 6 2 7 10 Future Testing INSPECT is now prepared for more intensive integrated testing on its way to becoming SPHERES X including a possible testing session in the reduced gravity aircraft RGA All of the requirements up to this point have been verified or are on track to be verified May 15 2014 16 831 SPHERES INSPECT Design Document 127 7 Conclusion MC HS MK INSPECT with its modular design utilizing the Halo structure rangefinding and thermal imaging capabilities and OpenCV compatibility is a solid first step forward towards the NASA HEOMD vision of free flying autonomous vehicles that can inspect navigate and characterize in an extravehicular space environment INSPECT aims to demonstrate these capabilities in an Earth based laboratory environment with the project eventually moving to testing on a Reduced Gravity Aircraft and then on the International Space Station inside and then eventually outside itself At its current stage in development INSPECT fulfills project budget allocations in terms of mass average power peak power data rate data processing and cost The current preliminary prototype can be found in the MIT Space Systems Laboratory with continued development on track to continue at least through summer 2014 8 Acknowledgements Thanks to the following supporters for guidance throughout the INSPECT Conception and Design process Profess
119. n the MIC PCB protects the ORF B Varying Halo battery voltage damages ORF from changes in the battery voltage C The ORF mount structure does not provide Thermal analysis of heat dissipation in microgravity sufficient heat dissipation Experimental measurement of heat dissipation in 1G Convection currents about the warm device chassis are driven by gravity acting on a density gradient within the air In microgravity there will be substantially less convection and the thermal resistance of the boundary between the air and the chassis will be higher This will increase the device s steady state temperature at a given power level Likelihood Figure 80 Optical Rangefinder Risk Fever Chart May 15 2014 16 831 SPHERES INSPECT Design Document 98 5 3 Thermographic Camera ThermoCam KAF Table 39 Thermographic Camera Risks and Mitigations Data capture immediately after powering A ThermoCam causes inaccurate temperature readings Wait 10 minutes after powering on ThermoCam for calibration before taking data Necessary calibration time drains battery life Analyze percentage of battery drainage and how it not allowing for full 30 minute operation length affects the operation length possible Thermal analysis of aluminum mount structure carried out by structures team and ThermoCam data analyzed for accuracy Modification of the mount structure design if accuracy is significantly affected The ThermoCam mount structure might not
120. nd gimbal while leaving a slit open for the RS 422 electrical interface It will attach to the CMG mount via 4 4 40 screws For the purpose of 16 831 this component will be 3 D Printed according to the drawing in Figure 64 CMG Enclosure Drawing May 15 2014 16 831 SPHERES INSPECT Design Document 79 UNLESS OTHERWBE PE CIRED Amt DAIE DIMENSIONS A VE IN INCHES Drawn IOIERANCES 3 MACIHON CHECKED TITLE AE aan BENDE a IWOPIACEDICHA 3 se z micare Iren CEOE PIC oa ap EA COE n p SIZE DWG NO REV Si ee ee be Gs CMG Flywheel Cover GER egen MARIE MERE E perm APPIAN CETTE SCALE 1 4 WEIGHT SHEET 1 OF 1 5 4 3 2 1 Figure 64 CMG Enclosure Drawing The design was revised to include reinforced fasteners half an inch taller as shown in Figure 59 Figure 65 Reinforced Enclosure 4 1 5 3 5 CMG Retainers This component to be implemented after 18 83x will allow for easy swivel ability and will bring redundancy into the design for safety purposes and structural integrity It will fit in from underneath the Halo CMG interface plate and attach directly to the CMG mount via 4 4 40 May 15 2014 16 831 SPHERES INSPECT Design Document 80 4 1 5 4 tapped holes and screws The CMG retainer component will effectively secure the interface plate between the CMG mount and itself This will allow for swiveling so long as the captive screws are not inserted and structural redundancy if they are inserted Power and Interfac
121. nd the Optics Mount attached must not exceed its allotted power budget when connected to a power source in order to meet criteria S 3 If the system still has power after being disconnected from a DC power source for over 30 minutes while doing standard testing operations then the system will meet criteria 1 1 If the VERTIGO Avionics Stack is able to process images from the Optics Mount the ORF and the ThermoCam during testing at least every 2 seconds then criteria l 8 will be met If the VERTIGO Avionics Stack is not able to make the appropriate computations in a real time environment the software being used to operate Halo and VERTIGO may need to be revised If after multiple revisions testing attempts it is apparent that the VERTIGO hardware is not capable of commanding the INSPECT array with only one sensor attached in the form of the 16 831 SPHERES INSPECT Design Document 108 Optics Mount then other options for the INSPECT on board computer may need to be considered 6 2 4 8 Tasks to be completed prior to testing AL HL 6 2 4 3 1 Software HL In order to proceed with VERTIGO Stack Testing all peripheral sensors compatibility and functionality must be verified during VERTIGO Emulation Testing VERTIGO Emulation provides almost exact software environment setting to that of actual Avionics Stack thus enabling each sensor to test without any risk of damaging actual Avionics Stack 6 2 4 3 2 Test preparation 1 Charge at leas
122. nent shall be utilized as the Data able to connect to the Halo via foundation for the Analysis amp H 2 Connection USB 2 0 or Ethernet S 4 sensor actuator suite Testing Verified All subsystems have been successfully connected to a computer using USB 2 0 or Ethernet Verification Unverified Halo Integration Testing scheduled for 18Apr 25Apr Needs to limit the amount of fuel and The system shall be power used by capable of operating for no INSPECT so that ISS fewer than 30 minutes future EVA operations Operation without refueling or are a reasonable DN Time recharging M 1 amount of time Analysis Verification Unverified Halo single component testing scheduled for 14Apr 18Apr The sensors shall point in the same direction and be Allows for combined Sensor placed no more than 50cm SX 1 field of view for l 8 Placement apart SX 2 sensors Inspection Verification Verified CAD models and machined mounts designed and inspected to confirm 6 2 4 Success Criteria AL HL The success of this test will be measured by the VERTIGO Avionics Stack s ability to receive input from the Optics Mount the ORF the ThermoCam and the CMGs through Halo make appropriate on board calculations and give resulting commands to the INSPECT system May 15 2014 If the Avionics Stack is able to receive images from the the Optics Mount the ORF and the ThermoCam then VERTIGO will meet criteria H 2 The SPHERES operating with Halo a
123. ng be tested in the SSL M 2 testing Analysis Verification Verified All testing has been successfully conducted and planned for the SSL Software The system shall be able to Allows for testing of l 7 Update update its software SX 4 new algorithms Analysis Verified The use of GPFs on VERTIGO and GSP on SPHERES insures inherent Verification updatability of software The sensors shall point in the same direction and be Allows for combined Sensor placed no more than 50cm SX 1 field of view for l 8 Placement apart SX 2 sensors Inspection Verification Verified CAD models and machined mounts designed and inspected to confirm INSPECT shall provide a minimum of 300Mflops of computing power at all Need to ensure times to support the sufficient resources to Computing execution of guest scientist SX 4 run code so system l 9 Power algorithms SX 5 doesn t crash Testing Unverified Current estimates are positive but confirmation testing scheduled to take Verification place Summer 2014 Linear exceed a linear momentum Prevents hazard if SAF 1 Momentum of 1 kg m s ISS 5 control is lost Testing Verified CONOPS testing conducted on SSL Flat Floor confirms max linear momentum of 1 038 kg m s which is less than what will be on ISS given the additional weight of the Verification air carriage The suite shall not be structurally mounted during ISS Safety SAF 2 Mounting transpor
124. ng the depth values These gathered data are then processed and transferred to GSP for future software developments and implementations Off board Processing HS Off board processing is not an INSPECT requirement However as INSPECT is a risk reduction project for future endeavors consideration has been given to how off board processing might be beneficial to the platform and how it might be done Off board processing may be conducted in two ways pending additional development after 16 83x One way is to do the processing on the data after the SPHERES has finished a set of maneuvers and the inspection data has been passed off to another likely more powerful computer after an experiment run The other way to do it would be to stream the data over a live connection as the SPHERES is running which would allow much more immediate data processing that could even be sent back to SPHERES to close a control loop One possible platform on which this could be done is the Robot Operating System ROS Using this system would allow connections to be programmed in that link an active SPHERES to an off board computer and leave only nodes of code that are required to run the SPHERES itself on the VERTIGO Avionics Stack Under this method all processing of information would be passed off to nodes that exist on another computer granting the capability to use a more powerful computer for operations than the Avionics Stack without having to upgrade the SPHERE
125. nspection Verified VERTIGO Avionics Stack supports data offload via USB using designated Verification dongle directly connected between host computer and avionics stack Excessive inertia will limit the flight time because more fuel will The system shall not exceed 11 be required for control S 2 Mass Limit kg in mass M 1 and movement Analysis Verification On track Total mass currently 8 079kg Excessive power draw The system shall not exceed a will present health peak power draw of 16 65 watts risks to avionics at each port 11 1V and 1 5 decreasing mission S 3 Power Limit amps M 1 lifespan Testing Verification Verified ORF requires greatest power draw of 13 36W The system shall use SPHERES provides a SPHERES as the primary M 2 consistent testbed that S 4 SPHERES _ testbed for all operations M 1 has ISS heritage Inspection Verification Verified All systems designed to interface with SPHERES Halo Requirements Each suite component shall Physical connect to Halo using the 4 Assures consistent H 1 Connection hole square screw pattern S 4 mounting Analysis Verification Verified All sensors and actuators connect via mounts SPHERES will be Each suite component shall be utilized as the Data able to connect to the Halo via foundation for the H 2 Connection USB 2 0 or Ethernet S 4 sensor actuator suite Analysis Verified All subsystems have been successfull
126. o process data receiving information from the sensor subsystems Ethernet and USB 2 0 cables transmit 1 Gbps and 280 Mbps of data respectively to and from the Avionics Box The Avionics Box also supports UART via pins 22 amp 24 and 30 amp 32 connecting it directly to the SPHERES DSP Time sharing enables multiple devices to operate simultaneously through a single switched Ethernet cable or a singles switched USB 2 0 cable Only on HPG shown in Figure 30 Halo Overall Layout are there two parallel and distinct designated USB ports Every other Halo Port supports one split USB 2 0 line McCarthy 2013 16 Figure 70 outlines the overall data flow from inboard to outboard SPHERES Avionics Stack Halo Motherboard Halo Port PCB and sensor or actuator The same data return flow applies in the opposite direction Figure 70 also displays the connection types between each stage in the data flow The Avionics Stack serves as the main hub router and central processor for all electrical signals and data for INSPECT The 1 2 GHz Via Nano U3300 Single Core OOE 1MB L2Cache processor has 4GB of DDR3 RAM at 1066 MHz two 64 GB Serial ATAs and runs Ubuntu Linux 10 04 Data transport to and from the Avionics Stack is achieved through Cat 5 Ethernet USB 2 0 and UART cables All processes run on a 1Hz cycle rate The VERTIGO Avionics Stack ICD contains a more detailed explanation of its interfaces and connections The pin layout of the 50 pin connector
127. obe the male Samtec 50 pin connector on the board to check for shorts and other places on the board can be connected to power for the component tests 6 2 1 2 MICPCB Inspection CL CK After the population of a MICPCB visual inspection must be carried out by someone who was not involved in the soldering and population of that board prior to any testing This intermediate step will catch a MICPCB with shorted out elements in the circuit or non ideal soldering and will prevent it from being destroyed during actual testing Multiple rounds of this intermediate testing could be used if the soldering was corrected Inspection was carried out in the following steps 1 2 Carry out a visual inspection of the board by someone who did not populate the MICPCB under the microscope if necessary a Check for visible shorts in the circuit b Check for cold solder joints and other soldering problems Re solder if necessary and then repeat the visual inspection steps Set the multimeter to beep mode and use the multimeter to check for shorts in the circuit a Ensure each pin on the 50 pin connector is not shorted to any other pin b Ensure the 8 Ethernet pins are not shorted to any other Ethernet pin c Ensure Vin and Vin pins of the voltage regulator are not shorted together Similarly ensure Vout and Vout pins are not shorted Ensure that power and ground pins of the screw terminal are not shorted e Determine the ON OFF position of the switc
128. ock Halo faces Figure 87 CMG Flat Floor Testing Structure shows the single component system as a whole Note as the CMGs are our heaviest subsystem counterweights will be required to even out the mass distribution These counterweights not shown in the figure will be placed so as to resemble the full system center of mass in the z x plane as well as the y axis moment of inertia This will prove to be useful for our CMG control software In order to provide the ability to test in the SSL the structures team developed a lazy susan setup Utilizing this setup future CMG teams can test certain rotational maneuvers at the convenience of the SSL bench May 15 2014 16 831 SPHERES INSPECT Design Document 106 Figure 86 Bare CMG Flat Floor Testing Structure Top wiring not shown Figure 87 CMG Flat Floor Testing Structure Figure 88 Alternative Bench Setup Utilizing Lazy Susan May 15 2014 16 831 SPHERES INSPECT Design Document 107 6 2 4 1 Requirement Verification Table 42 Stack Testing System Requirements System Requirements Excessive power draw The system shall not exceed a will present health peak power draw of 16 65 watts risks to avionics at each port 11 1V and 1 5 decreasing mission S 3 Power Limit amps M 1 lifespan Testing Verification Verified ORF requires greatest power draw of 13 36W alo Requireme SPHERES will be Each suite compo
129. ocument 38 Optical Range f 6 52 finder Thermo graphic 16 5 14 85 3 i Camera 11 85 79 80 12 12 18 38 Total Allocated Power W 54 5 Total Allocated Power Less 10 Margin W 49 05 Total CBE Average Power W 16 67 Total Remaining W 32 38 66 01 Total CBE Peak Power W 34 14 Total Remaining W 1481 30 40 3 3 Data Rate and Data Processing JB Table 4 Data Rate Budget Allocation outlines the data rate budget allocation of the INSPECT system The Halo structure provides a single split Ethernet connection 4 twisted pairs and a single split USB 2 0 connection on each Halo port and a single split Ethernet connection and two designated USB 2 0 connections on the Halo port pre designated for the VERTIGO Optics Mount HPG as outlined The amount of data that can flow through these connections well exceeds the data that each subsystem will transmit more details available in Section 4 2 5 Table 4 Data Rate Budget Allocation Data Rate Budget S Allocated Allocated opg Allocated ubsystems Data Rate Less 10 Data Mbps Margin MPPS Mbps Connection Optical Rangefinder 0 812 449 188 99 82 1x Ethernet Thermographic Camera 500 450 4 3 445 7 99 04 1x Ethernet CMGs 160 144 1 143 99 31 1x USB 2 0 TOTAL 1480 1332 13 332 1318 668 99 00 Table 5 Data Processing Budget Allocation outlines the budgeted Data Processing in units of millise
130. om Eagle CAD 1771101PHEONIX CK 151 Figure 117 Voltage regulator used on the MIC PCB custom Eagle CAD S24SE12002PDFA CK 151 Figure 118 Ethernet connector used on the MIC PCB custom Eagle CAD SS 7188V A NF CK 152 Figure 119 Printed Circuit Board for the CMGs schematic NM GP Chi 152 Figure 120 a and b Integrated INSPECT Assembly with Side View 153 Figure 121 SPHERES Assembly iii 153 Figure 122 VERTIGO Goggles Subassembly ii 154 Figure 123 VERTIGO Avionics Stack Subassembly ssssssssseeeenennen nennen 154 Figure 124 Halo Subassembly with SPHERES and VERTIGO Avionics Stack 154 Figure 125 Thermographic Camera Summary iii 155 Figure 126 Thermographic Camera with Mount ii 155 Figure 127 Optical Rangefinder Summary iii 156 Figure 128 Optical Rangefinder with Mount ss 156 Figure 129 CMG Mounting Assembly Components Side and Back Views 157 Figure 130 Integrated CMGs in Box 90 Control Configuration 157 Figure 131 Graphical interpretation of requirements flOW sssseesseesseesseeeneessrsnrnstrnsennetnnssrnntnnnnnnnnnent 159 List of Tables Table 1 Required Power and Resistors sise 24 Table 2 Mass Budget Allee eel Rete re tet e aeree t eo ieee ahd 38 Table 3 Power Budget Allocation itt ER genet E ete tege eee E LER EE ee 38 Table 4 Data Rate Budget Allocation sise 39 Ta
131. om the ThermoCam using FLIR Tools are stored with an associated temperature value in degrees C for each pixel A color image taken with FLIR Tools was imported into and read in MATLAB displaying the image data as a matrix of truecolor RGB values Using MATLAB the RGB matrix was converted to a matrix of grayscale intensity values Through a pixel by pixel comparison of the thermal image acquired from FLIR Tools and the grayscale intensity version of the same image acquired through MATLAB analysis a series of 15 pixel intensity values were mapped to their corresponding temperature values Using this process a linear relationship between the pixel temperature value in degrees C T and the pixel intensity value was determined to be T 0 22 x1 22 7 R 0 93 The raw image data acquired by the VERTIGO Avionics Stack was imported into MATLAB The data matrices of pixel intensity values were converted to matrices of pixel temperature values in degrees C using the above equation Moving forward a rigorous analysis should be carried out in order to develop a more accurate process of converting pixel intensity values transmitted from the ThermoCam to temperature values Mass KAF The mass budget for the ThermoCam system is outlined below in Table 24 Thermographic Camera Mass Breakdown The largest contribution comes from the system mount Other contributions come from the FLIR A5 camera and the MICPCB and wiring needed to interface the Ther
132. omputer and the timing constraints it imposes 12 2 Hazcams HS KH 12 2 1 Purpose and Relevance to INSPECT Hazard Avoidance Cameras Hazcams will be used to avoid collision with other objects primarily the ISS when a SPHERES is in a tightly confined area 12 2 2 Requirements Satisfied ID Requirement Parent Rationale Verification ISS 5 The system shall not be a M 2 Safety is key for mission risk Testing hazard on the ISS reduction H 2 Each suite component shall be S 4 SPHERES will be utilized as Testing able to connect to the Halo via the foundation for the USB 2 0 or Ethernet sensor actuator suite H 3 Each suite component shall S 4 Halo power settings Analysis operate on a 11 1 volt 5 amp power supply 12 2 3 Trade Study Table 50 Hazcam Tradespaces Avg Diagonal Frames Resolutio Model P 8 Field of Cost Mass Volume ower sec n View 0 036 x IDS uEye LE 0 65W 70 7 200 0 012 kg 0 036 x 15 5M 0 020 m Lifecam DUO X Cinema 2 5 W 73 0 70 0 0953 kg 0 046 x 30 5M 0 040 m 0 096 x Bm 25W 895 80 O0 080kg 0 034 x 30 5M 3 0 080 m 12 2 4 Decision Made The decision was made to not include a visual hazcam system for several reasons First the amount of data collected by these cameras was deemed too high for the purpose that they serve and slowing down the data collection and processing rate to accommodate this limitation would slow down the entire system significantly The
133. onboard INSPECT we will use mock Halo faces as shown in Figure 85 CMG Flat Floor Single Component Testing Structure These structures represent halo in all geometrical dimensions and will provide enough support to be a direct mount for the CMG subassembly System Level Tests GK The series of system level tests is composed of three separate tests The first is a preliminary test involving dummy weights to symbolize the INSPECT system on an air carriage The test evaluates translation using SPHERES thrusters and optimal pressure settings Following completion of the preliminary test and all subsystem single component tests an acceptance test will be done using all subsystems attached to the Halo and SPHERES Mechanical electronic and data connections will be assessed and pending compliant results the system will be moved on to its final phase of integrated testing Objective The objective of the integrated systems test is to test the concept of operations maneuvers on the flat floor of the SSL The sensors will be taking in visual stimuli from a 2m x 0 5m test board as the CMGs pair with SPHERES thrusters to control movement of the INSPECT system The test board is specifically designed with a series of stimuli meant to test at below and above all sensor requirements for data comparison between the sensors and to actual measurements From the analysis of the data we will be able to discern if the INSPECT system is functional and prepared for
134. or which then relays the data to Halo via the ERF8 025 01 S D RA TR female connector on the Halo Port 1 However during integration and testing of the MICPCB in May 2014 the data capabilities of the board were not used because Halo did not have working data connection on the ORF port The ORF instead transmitted data through a central Ethernet switch that was connected into the VERTIGO dongle See the Testing section below for more details The intent is use the same Ethernet connector on the current MICPCBs in the future to route data through the MICPCB after more testing CK 4 1 3 5 1 Use of the 850 nm Spectrum May 15 2014 16 831 SPHERES INSPECT Design Document 59 The use of the 850 nm infrared spectrum creates an interface issue between the ORF and the SPHERES US IR Global Metrology system The Metrology system is synchronized and activated by pulses of infrared light emitted by the master SPHERES satellite When the Metrology beacons receive an IR pulse they respond with an ultrasound pulse 8 The SPHERES satellites have several receivers for both the IR and ultrasound pulses The SPHERES satellites measure the time between their receipt of the IR pulse and the receipt of the ultrasound pulse from each beacon 8 This time multiplied by the speed of sound gives the distance from each beacon to each receiver on the SPHERES satellite The Metrology system software uses these distance readings to determine the position and orientation of t
135. or David Miller Professor Kerri Cahoy Professor Jonathan How Dr Alvar Saenz Otero Mr Paul Bauer Ms Jennifer Craig David Sternberg 2 t Bryan McCarthy USAF 2 Lt Drew Hilton USAF Tim Setterfield Todd Sheerin Kit Kennedy Dr Brent Tweddle May 15 2014 16 831 SPHERES INSPECT Design Document 128 9 References 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 May 15 2014 C Cassidy Interviewee Interview 05 12 2013 J P E a A G R Mark O Hilstad The SPHERES Facility Description MIT Space Systems Laboratory 2013 B McCarthy SPHERES Halo Presentation Cambridge MA Feb 6 2014 B McCarthy and C Jewison MIT Space Systems Laboratory Cambridge MA 21 Nov 2013 B McCarthy Halo PDR MIT Space Systems Lab Cambridge 2013 B E Tweddle Computer Vision Based Localization and Mapping of an Unknown Uncooperative and Spinning Target for Spacecraft Proximity Operations Cambridge Massachusetts Institute of Technology 2013 MESA Imaging SwissRanger SR4000 Online Available http www mesa imaging ch swissranger4000 php Accessed 28 Feb 2014 A Saenz Otero Design Principles for the Development of Space Technology Maturation Laboratories Aboard the International Space Station MIT Department of Aeronautics and Astronautics Cambridge 2005 D Miller SPHERES Flight Critical Design Review 15
136. ow SPHERES to rest with its Z axis in the horizontal plane all while minimizing thruster plume impingement The final outcome is shown in Figure 97 Figure 95 Inspect Without Structural Support wiring not shown 6 2 7 6 1 Structural Components The testing structure will be comprised of 7 total components 5 of which are unique and all of which can be seen in Figure 97 The 3 puck air carriage as well as the propulsion deck with the 4 associated 1 inch x 1 inch clamps was provided for the INSPECT team The Cradle was 3D printed based off of an amended version of the SPHERES SLOSH project making it press fit into the propulsion deck and with a lighter weight and void of thruster blockage in any direction which better fits INSPECT s testing needs Lastly are the peripheral mounting mechanisms There are two at the front of our system for the ORF and ThermoCam sensors These will act purely as supports for these subsystems to ensure no loading on the Halo face Since platform height accuracy of this setup is non trivial these supports will be adjustable via two softheaded screws that will come up towards each of the bottom plates of our sensor mounts The rear extremities are for our CMG subassembly Two clamps will act as complete constraints grabbing onto the CMG control box mounting structure as seen in Figure 96 and Figure 97 These clamps will ensure that our CMGs do not spin SPHERES out of its cradle imparting all commanded torques throu
137. peration Total Score 5 3 4 Meeting the Halo power constraint is a high priority as failure to meet this constraint would necessitate a re design of the Halo power supply or other intervening measures 3D scanning without a gimbal is a medium priority as gimbaling the sensor increases design complexity and May 15 2014 16 831 SPHERES INSPECT Design Document 133 makes attitude control more difficult Sunlight operation is a low priority as only artificial lighting is present inside the ISS None of these sensors meets outgassing thermal radiation requirements for operation outside of station As such different sensors will be required for SPHERES X 11 2 Thermographic Camera TW The Thermographic Camera chosen was the FLIR A5 This decision was reached by comparing the cameras in Table 46 using the trade space summarized in Table 47 Table 46 Thermographic Cameras Candidate Specifications Field o Thermal Thermal Cost of Resolution GE View SEES OSXL 1 995 oe 140 x 140 i oe 17 Omega o 20 OSXL o 1 995 ee 160x120 0 07 C A 650 E30 29 x 40 500 UT qe 52 6 MC320L 1 S 320x240 0 06 C de 39 7 FLIR A5 0 2 300 SEN 80 x 64 0 05 C P 60 Table 47 Thermographic Camera Tradespace Resolution Total Thermal Thermal Sensitivity Range 3 2 Cost Mass Volume Field Mikron Thermo Tracer 7302 MC320L May 15 2014 16 831 SPHERES INSPECT Des
138. phic Camera Summary Figure 126 Thermographic Camera with Mount May 15 2014 16 831 SPHERES INSPECT Design Document 155 14 3 2 Optical Rangefinder A summary of the Optical Rangefinder is depicted below along with the mounting structure as discussed in Section 4 1 3 3 Ethernet data and Ring of power 850 nm connections LEDs on back face Camera Lens on front face Mounting holes on bottom face Figure 127 Optical Rangefinder Summary Figure 128 Optical Rangefinder with Mount May 15 2014 16 831 SPHERES INSPECT Design Document 156 14 3 3 CMG Subassembly 4 The mounting structure for the Honeybee CMG is detailed in Section 4 1 5 CMG Enclosure 1 of 12 dampeners per assembly Honey Bee Control Box Enclosure Honey Bee CMGs Figure 129 CMG Mounting Assembly Components Side and Back Views The fully integrated CMG subsystem is represented in the box 90 control configuration without wiring in Figure 130 below Figure 130 Integrated CMGs in Box 90 Control Configuration May 15 2014 16 831 SPHERES INSPECT Design Document 157 15 Appendix F Requirements Flow JW 15 1 Mission Requirements Mission requirements state the overall goal of what the SPHERES INSPECT platform plans to achieve 15 2 Constraining Requirements Constraining requirements relate to other systems that INSPECT will have to integrate with For proper integration INSPECT will have to be designed to meet the ex
139. r data to image alignment procedure A rough estimate of FLOPs necessary to perform the software operation outline in Figure 39 VERTIGO Avionics Stack Software Data Flow Diagram was determined using the assumption that the number of transformations necessary to align the three images was on the order of one Alignment consists of matching an image from each sensor to existing images from another so that each single 5D voxel frame of a scene consists of 3 distinct frames from each sensor with the ORF providing three values per pixel These calculations were used to determine that a 1 HZ cycle of the sensors to match what was imposed by SPHERES was possible given the hardware GP May 15 2014 16 831 SPHERES INSPECT Design Document 54 4 1 2 9 VERTIGO Emulation HL VERTIGO Emulation provides the same software environment as that of the actual Avionics Stack but on different hardware such as the users computers The purpose of the emulation is to allow testing and implementation of the VERTIGO system without the use of the actual Avionics Stack which significantly increases accessibility for first time users who are learning and developing VERTIGO based programs such as the GSP and GPF Goggles Program File It uses Linux Ubuntu 10 04 with pre installed OpenCV 2 3 1 GPF and test projects However it should be noted that there is a discrepancy between the actual and the emulation processing power due to the difference between the emu
140. r to a full system acceptance test The final test completed was the full integrated system test in which all components were integrated into the INSPECT system and the Concept of Operations maneuvers were completed on the flat floor At that time all sensor and system level requirements were evaluated for full integration and functionality 6 2 Testing Plan JW 6 2 1 6 2 1 1 The goal of the testing procedures is to verify all testable requirements ensure subsystem integration and reduce risk to the mission operators facilities and system components MICPCB Testing CL CK The purpose of initially testing the MICPCBs separately from ORF and ThermoCam is to ensure that power and data can be successfully received and transmitted through the board before connecting it to the relevant sensors The following procedure must be done for each populated MICPCB Note that these are the testing procedures for the MICPCB without the health monitoring system Equipment Materials CL CK The equipment necessary for the initial MICPCB testing is as follows May 15 2014 16 831 SPHERES INSPECT Design Document 101 Fully populated MICPCB DC power supply Alligator clips 2 Stripped wires 2 Power Resistors of varying resistance 10 11 15 20 250 were all used to test the MICPCB Multimeter with probes Breakout cable with female Samtec 50 pin connector on one end recommended but not necessary more stripped wires could be used to pr
141. rature controllers The eight thermal stimuli will be heated using 2 systems of four resistors in parallel Dimmers will be used for more dynamic voltage control allowing for more precise heating Figure 7 illustrates the design and Table 1 shows the required power output of each resistor along with the needed resistance for a 20 volt DC source Dimmer 1 Dimmer 2 Dimmer 3 Dimmer 4 AC Voltage Source Resistor 1 Resistor 2 Resistor 3 Resistor 4 Figure 7 Heater Circuit Diagram Note Dimmers are represented by variable resistors in the diagram Dimmers NOT variable resistors will be used for the real system JW GK Table 1 Required Power and Resistors May 15 2014 16 831 SPHERES INSPECT Design Document 24 5 C 10 C Voltage Resistance Q Voltage Resistance Q 3x3cm 4 46 33 3 42 20 5x5cm 3 85 33 4 08 33 3x3cm 4 03 50 4 03 100 2 3 1 2 May 15 2014 Each thermal stimuli is a manufactured aluminum plate that has the appropriate resistor attached to its back face The front face of the plate is covered by black electrical tape to prevent thermal reflection caused by the reflective aluminum surface allowing for a uniform temperature reading over the entire surface area of the plate The plate is then inserted into its place within the test board and attached to its dimmer The test board used for integrated testing in May 2014 is displayed in Figure 8 KAF Figure 8 INSP
142. reakdown iii 81 Table 28 CMG Average Power Breakdown iii 81 Table 29 CMG power requirements TA 81 Table 30 le NEE ie EE 86 Table 31 CMG Financial Budget iii 86 Table 32 Subsystem Processing Summary isa 87 Table 33 Power Requirements for Avionics Processor Box 6 91 Table 34 Worst case timing analysis ete ete el eet ege crediti Pepe Ru 92 Table so Thermal Le ates eet int ee tette aetatem etate etatem eee 95 Table 36 Power Draw by Subsysterri ctn e rrt e rd E Fa e E el ree ct e E E PL Dig veas 96 Table 37 VERTIGO Goggles Risks and Mitigations ssssssseeeseneeenenenen nene 97 Table 38 Optical Rangefinder Risks and Mitigations sess enne 98 Table 39 Thermographic Camera Risks and Mitigations sssnnensnneeesnneee nt nnnetr rnst tnnnnrnnnnntnnnnneen nnne ennan 99 Table 40 CMGs Risks and Mitigation ir 99 Table 41 System Technical Risks and Mitigations cceccceeeeeeeeeeeeeeeeceeeeeeeaeeeeaaeseneeeseeeesaeeseaeeseaes 100 Table 42 Stack Testing System Heouirements enne 108 Table 43 Rangefinder Technology Comparison c cccsececeeeeeeeeeeeeeaeeeeeeeceeeesaaeeesaaeseeeeeseaeeesaeeseaeeseaes 132 Table 44 Optical Rangefinder candidate Specifications c ccceccceeeeeceeseeceeeeeeeaeeeeaaeseeeeeseeeesaeeseeeteaes 133 Table 45 Optical Rangefinder Pugh Chart enne nnns ens 133 Table 46 Thermographic Cameras Candidate Specifications s
143. rification Verified CONOPS designed to perform all maneuvers in JEM volume The suite shall be able to fit into a full size Crew Transfer Bag Need for storage on ISS ISS Storage CTB 42 5 cm by 50 cm by 25 ISS in TBD storage 2 Size cm M 2 configuration Inspection Verified Initial inspection confirms system must be broken down and mounts removed to Verification fitin Crew Transfer Bag Launch vehicle The system packaging shall be requirement compliant with Progress Soyuz http kscsma ksc nasa ISS Package safety document P32928 103 gov GSRP Document 3 Launch and SSP 50146 Attachment D M 2 ssp30599D pdf Analysis Unverified No system packaging has been designed or manufactured and is scheduled Verification for Summer 2014 Need to fit through The fully integrated system shall airlock to ISS be capable of fitting in the 57 6 accommodate future 4 Airlock Size x 83 x 80 cm JEM airlock M 2 capabilities mission Inspection May 15 2014 16 831 SPHERES INSPECT Design Document 15 outside ISS Verified CAD models indicate entire system cubic volume of 0 0363357m using square mockups for different subassemblies SPHERES Halo ORF Thermo CMGs Verification VERTIGO stack and VERTIGO goggles System Requirements Allows for transfer of data from avionics The system shall allow for stack to another stored information to be processing device for S 1 Downlink transferred to a host computer M 1 data analysis I
144. s It can also take a slew of gimbal rates which allows for an entire series of maneuvers to be specified at once The code that underlies the GUI is also Windows specific which presents challenges in adapting the communications with the CMGs to VERTIGO s Linux system A low level API was also provided by Honeybee 15 which specifies the bytes that must be sent over the CMG s serial connection to get status information and send commands to the CMGs The message is built using a series of hexadecimal packets that all contain the following in order a message start section a command type a message body length a message body and a CRC checksum May 15 2014 16 831 SPHERES INSPECT Design Document 85 4 1 5 8 Two pieces of software were developed to support testing of the low level communication The first piece of software calculates the CRC checksum from a provided binary message and verifies CRC checksums if a binary message is given along with its checksum This is necessary because the checksum is determined by the message and must be calculated rather than explicitly given by the Honeybee API The second piece of software is aimed at establishing serial communication between the CMGs and a computer programatically rather than through a GUI Eventually this software will replace the GUI and provide an will serve as the core means of communication to and from the CMGs Largely due to time constraints this software is currently only able
145. se cameras normally collect at frame rates of 5 60 FPS and return frames of up to 5 megapixels Even if the frame rate was slowed more and the image resolution decreased the processing of these images would require a human observer to constantly check on the images to ensure that no hazards were present As such proximity sensors were determined to be a better type of sensor to fulfil the requirements that hazcams were geared towards May 15 2014 16 831 SPHERES INSPECT Design Document 139 12 2 5 Incorporation If incorporated multiple 3 5 hazcams would clip on to Halo They would be pointed in different directions to give as much of a visual field of view as possible Power and data interface would both be through USB 2 0 all cameras in the trade study had this capability though due to the port limitations on Halo the cameras would have to share a single Halo port using a USB splitter Some cameras have embedded software to change image quality in different ways so image quality and frame rate would be adjusted to meet data and human inspection requirements Lighting will be a major limitation for the hazcams Unless an additional lighting system similar to the VERTIGO strobe lights is incorporated these cameras would be largely useless for periods when adequate lighting is not available 12 3Proximity Sensors KH 12 3 1 Purpose and Relevance to INSPECT Proximity Sensors will be used to avoid collision with other objects pri
146. sequent navigation relative to ISS 12 1 2 Requirements Satisfied GP ID Requirement Parent Rationale Verification SX 1 The system shall provide a M 1 Needed to fulfill mission Testing functional API for localization goal properly test the and mapping system SEN 2 The system shall determine the SX 1 Defines ranging limits Testing distance to a target object SX 2 accurate to within 10 cm with precision to 2 cm up to 10 meters away 12 1 3 Trade Study Since GPS signals can not be received within the ISS because the GPS constellation is not visible from inside the use of GPS on INSPECT for the purpose of testing is more complex than any other sensor choice Simulated GPS signals would have to be used to test within the ISS It is important to note what the capabilities of GPS as a navigation tool were as all simulation techniques would revolve around the capabilities of GPS after receiving GPS data and determining position Possible options were to send up pseudolites to act as satellites or to use the existing metrology system on SPHERES as a pseudo GPS Of the two options the latter would be the option of choice since it makes use of existing and well tested systems In order to examine whether the acoustic metrology system on SPHERES would function as a testing double of GPS the capabilities of the two systems would need to be contrasted Specifically the positioning accuracy of the acoustic metrology
147. sisi 23 Figure 6 Continuous Change of Depth Stimulus su 23 Figure 74 Heater Circuit Diagram io p Et e i eroe ehe e read egt Dee 24 Figure 8 INSPECT Test Board May 2014 sss iii 25 Figure 9 Horizontal Field of View is 26 Figure 10 Vertical Field of View sisi 26 Figure Maneuver l WT 28 Figure 12 Manguver 2 t edd b exte eR Get PUR tn exe e eid Ee Ee Puteo D ciun a eevee dead 28 Figure 13 Mangeuver dise nt A distent nib ie tenete ign tien 29 Figure 14 Maneuver EE 29 Figure 15 EE 29 Figure 16 Maneuver pes Ree ie dade e led eee elie 30 Figure 17 Maneuver EE 30 Figure 18 Maneuver B at pecie eite eet Eee Tere ra mena ee RO opera elle ree pepe deut 30 Figure 19 Modeled Inspections 2 otto teo en nan le 31 Eigure 20 SPHERES Summary itti i t ne tar pete a E esa ec e ep ee 32 Figure 21 Halo Structure Pictured with SPHERES and VERTIGO Avionics Stack 3 32 Figure 22 CMG External Power and Data Cables sese enn 33 Figure 23 ORF ThermoCam and Ethernet switch connections ssssssssssrnssnrrsertrrnsrtnrnntnnnnnnnn nnne nn nnne 34 Figure 24 a and b VERTIGO Goggles Assembly Avionics Stack with Optics Mount 4 and Integrated SPHERES VERTIGQO System x ierit deerit t Ee tei e doi ete ra EO n aeu eng peste dde bean Pe ad 35 Figure 25 VERTIGO dongle and alternative Optics Mount secured to INSPECT ossssssesseeseeeseeeseeeeeeeese 35 Figure 26 INSPECT Integrated CMG
148. software architecture 8 61 Figure 45 The distribution of position error samples measured with the ORF operating continously 10 62 May 15 2014 16 831 SPHERES INSPECT Design Document 6 Figure 46 The distribution of position error samples measured with the ORF powering its lights for approximately 5 ms every 1000 ms 10 63 Figure 47 Message based synchonization of the ORF and the Metrology system MV 64 Figure 48 pseudocode for the message based architecture MV 64 Figure 49 Timer based synchonization of the ORF and the Metrology system MV 65 Figure 50 pseudocode for the timer based architecture MN 65 Figure 51 FLIR A5 Thermographic Camera 12 nnns 68 Figure 52 The CAD model for the sensor mount with the Thermographic Camera in it for scale Holes on the bottom plate allow for installation of the Thermographic Camera NC 69 Figure 53 Pin assignment for M12 male connector male side view CL 11 70 Figure 54 Mapping pin to signal only pins 1 and 2 are used with ThermoCam CL 11 70 Figure 55 ThermoCam Software Flow Diagram iii 72 Figure 56 Honeybee LEO CMG ist aiit ettet de ene ae siepe te e EE san cere e P EP lads 75 Figure 57 16 851 CMG and Control Box Assembly Box 90 Configuration 75 Figure 58 CMG Mounting Assembly siennes 76 Figure 59 16 851 CMG Mounting Assembly Components Side an
149. ss 134 Table 47 Thermographic Camera Tradespace eene nennen nnns nennen 134 Table 48 Actuator Candidate Specifications esseessessseeeesseett ie ttettttnttnn ttnn ntnn ntn nenn nennntu nnen nnnnnnen nnet 135 Table 49 Attitude Control System Pugh Chart sisi 135 Table 50 Hazcam Tradespaces sise 139 May 15 2014 16 831 SPHERES INSPECT Design Document 9 List of Acronyms Acronym Meaning ADCS Attitude Determination and Control System CMG Control Moment Gyroscope CPU Central Processing Unit CBE Current Best Estimate DSP Digital Signal Processor FPS Frames Per Second GPF Goggles Program File HEOMD Human Exploration and Operations Mission Directorate HP Halo Port HPG Halo Port Goggles IMU Inertial Measurement Unit INSPECT Integrated Navigation Sensor Platform for EVA Control and Testing ISS International Space Station LIDAR Light Detection and Ranging MIT Massachusetts Institute of Technology MIC Multiple Interface Connection NASA National Aeronautics and Space Administration NETD Noise Equivalent Temperature Difference ORF Optical Rangefinder PCB Printed Circuit Board PoE Power over Ethernet PPTC Polymeric Positive Temperature Coefficient Device ROS Robot Operating System RTD Resistance Temperature Detector SLAM Simultaneous Localization and Mapping SPHERES Synchronized Position Hold
150. striction necessitated the continued connection of the dongle to both the INSPECT system and computer during testing it was secured to the Y face of the SPHERES Figure 20 with electrical tape allowing for easy removal to access the SPHERES battery compartment also located on that face While being secured the dongle was carefully oriented so as to ensure no interference with the SPHERES thrusters in use The dongle and alternative Optics Mount can be seen in Figure 25 KAF Figure 25 VERTIGO dongle and alternative Optics Mount secured to INSPECT May 15 2014 16 831 SPHERES INSPECT Design Document 35 In order to provide attitude control INSPECT incorporates two Control Moment Gyroscope CMG pairs Figure 26 shows the integrated INSPECT system with CMGs depicted with transparent enclosure covers in a Box 90 configuration A discussion of the CMG subsystem design is located in Section 4 1 5 Figure 26 INSPECT Integrated CMG Assembly View Wiring Not Pictured JS Figure 27 displays the integrated INSPECT system with Optical Rangefinder and Thermographic Camera pictured with mounting structures VERTIGO Goggles and CMGs MK Figure 27 a and b Integrated INSPECT System Configuration Isometric and top views respectively JS The final configuration used for integrated testing in May 2014 is displayed in Figure 28 and Figure 29 KAF May 15 2014 16 831 SPHERES INSPECT Design Document 36 May 15 2014
151. svsevsccevsveescesescesecsccsseccseevdencvecesscssss 155 14 3 1 Thermographic Camera 155 14 32 Optical Rangefilhider i ue eren re e e D NT aan 156 14 3 3 CMG Subassembly Wl easet rh err eae tree ener e Eege geed eege 157 15 Appendix F Requirements Flow JW eeeee eee e eene eene nenne nennen nnne 158 15 1 Mission Requiremients 55 Ire tope Fo eor Eee oaa od e our ENEE ENEE 158 152 Constraining Requirements 5 Eege EE denis er dires Se EUER EES EE 158 15 3 Development Requirements ccccssssccccssssccccssssccccenssceccenssceccacssseceacsscsceanssssceaassssceaasnss 158 15 3 1 SPHERES X Requiremients israel nn ete ee du ine e edet ede tese soie e du ie ee ttes 158 15 3 2 INSPECT Suite Requirements ii nennen nennen nennen nennen nennen nennen nenne 158 15 3 3 Sensing Requirements eec Ret de ente o lise 158 15 3 4 Control and Actuation Requirements is 158 May 15 2014 16 831 SPHERES INSPECT Design Document 5 List of Figures Figure 1 SPHERES operating inside ISS left SPHERES microsatellite middle concept of free flying autonomous systems derived from SPHERES architecture near ISS right 25 11 Figure 2 Team Organization Structure JB usines 14 Figure 3 HEOMDB MissSion EIoW icerum cente rode dvd ve cane uev ui dee uua ede ege aod e dp eU vage 14 Figure 4 Layout of the Testing System sisi 22 Figure 5 The Inspection Landscape
152. system needs to be compared with that of GPS May 15 2014 16 831 SPHERES INSPECT Design Document 137 Estimation Error Baseline Component Max cm RMS cm Magnitude 35 8 42 Along Track B 369 4 5 Cross Track B 280 24 Radial 2 912 6 8 Kin Correction Availability 96 3 Ambiguity IA Estimation Fixing Rate Fail Rate 96 WL ambiguities 98 0 0 0 L1 ambiguities 98 0 3 6 Table of relative navigation performances of LEO Carrier based Differential GPS 17 Based on the table of relative navigation performances of in orbit GPS we observe relatively large maximum estimation errors compared to the current metrology system currently on SPHERES As such a direct one to one substitution for the purpose of testing would not provide accurate results nor the appropriate risk mitigation desired Adaptations that would have to be made to the ultra sound metrology system in place are discussed in 12 1 4 inclusion on INSPECT and 12 1 5 inclusion on SPHERES X 12 1 4 Decision Made GP It was decided not to include a GPS on INSPECT dude to the difficulty of testing inside the ISS It is recommended that such a system be used for SPHERES X in the future as a means of navigation and localization Based on the trade study comparing in orbit GPS positioning accuracy to what can be currently be obtained by the acoustic metrology system it is determined that we can simulate the use of in orbit GPS by inducing an error
153. t 10 Nikon EN EL4 batteries for Halo and the VERTIGO Avionics Stack 2 Download GPF Goggles Program File to VERTIGO Goggles 3 Calibrate VERTIGO cameras using Camera Calibration 4 Clear space in SSL bench area for testing 6 2 4 4 Setup e Mount Halo to a SPHERES o Using standard Halo procedure to be determined e Mount the VERTIGO Optics Mount to Halo o Using standard Halo procedure to be determined e Conditional Start Halo INSPECT software on a laptop o Dependent on whether Halo will have a software interface for an external test computer e Prepare SPHERES battery packs with kapton tape e Connect SPHERES to a DC Power Source 6 2 4 5 Procedure Note The test procedure is intentionally inexplicit as the exact software testing nature of Halo has not yet been determined This test plan will be updated to comply with standard Halo INSPECT procedure 1 Power on the INSPECT system 2 Establish communication between Halo and SPHERES with Halo INSPECT GUI a GUI should display contact with the SPHERES including its ID and communication method 3 Run BlobTrack test program using steps similar to preliminary testing a Change parameter file of BlobTrack to vary frequency of image capture May 15 2014 16 831 SPHERES INSPECT Design Document 109 10 11 12 6 2 4 6 6 2 4 7 b Test BlobTrack program at frequency of 0 5 Hz 1 Hz and 2 Hz Power INSPECT system off Replace SPHERES DC power source with batt
154. t of the INSPECT platform May 15 2014 16 831 SPHERES INSPECT Design Document 21 Beacon Location m 1 25 1 1 25 1 1 25 1 25 0 0 1 25 MUN 4 2 0 1 25 Figure 4 Layout of the Testing System 2 3 1 1 Inspection Landscape A quasi 2D 200cm x 61 cm test board has been designed to quantitatively judge an inspection operation An effort was made to create a landscape that displays each stimulus at a range of resolutions 1 A specification more stringent than the requirement 2 At the requirement 3 Aspecification much easier to achieve than the requirement The ability to inspect a broad spectrum of stimuli will allow for complete requirement testing and gives flexibility for future inspection studies May 15 2014 16 831 SPHERES INSPECT Design Document 22 Figure 5 The Inspection Landscape 2 3 1 1 1 Visual stimuli A checkerboard pattern of various resolutions can be used to test the distance at which the grey scale visual camera can no longer differentiate visual light The following resolutions have been chosen 1 0 5 cm x 0 5 cm More stringent than requirement 2 cm x 1 cm At requirement 3 5cmx 5 cm Less stringent than requirement 2 3 1 1 2 Depth Stimuli A continuous sloping test section ranging from 10 cm to 10 cm in depth from the neutral depth of the board allows for precise range resolution from testing from any distance 10 cm 25 cm 25 cm 100 cm
155. t on its rear face will be on 5 Switch off PCB 6 Turn Halo off e May 15 2014 16 831 SPHERES INSPECT Design Document 113 Figure 91 ThermoCam being powered by MIC PCB and Halo blue indicator LED is on CL 6 2 5 5 MICPCB Halo a Single Sensor and Ethernet Switch CL KAF Because there is currently no data connection on the Halo ports to which the ThermoCam and ORF will be connected it is not possible to test data on the MICPCB including data pins on the male 50 pin connector RJ45 Ethernet port and the differential pair traces Instead an Ethernet Switch is used as a replacement see Figure 92 and Figure 93 The Ethernet cables coming from the sensors will be connected to two ports in the switch and a third Ethernet cable will connect the switch to an Ethernet port on the VERTIGO Avionics Stack The data and images being transmitted from the ThermoCam ORF and VERTIGO Optics Mount via Ethernet can be viewed on a computer by connecting the VERTIGO dongle from the Avionics Stack to the computer May 15 2014 16 831 SPHERES INSPECT Design Document 114 Figure 92 10 100 Ethernet switch used for data transfer during MICPCB Halo sensor interface testing ThermoCam and VERTIGO Avionics Stack connected ports 1 and 5 respectively KAF CL bine A gt Figure 93 Gigabit Ethernet switch to be used during flat floor testing CL Initially the Ethernet switch will not be connected to the Avionics Stack but will instead b
156. tation ISS 5 Requirement Inspection Verification Verified In order to fulfill ISS 2 this requirement is also met The suite shall not contain Hazardous any substance that would ISS Safety SAF 3 substance cause a hazard if released ISS 5 Requirement Analysis Verification Verified No hazardous substances detected The suite shall not create a hazard in the event of depressurization or re Depressuriza pressurization of the ISS Safety SAF 4 tion surrounding volume ISS 5 Requirement Analysis Verification Unverified No pressurization testing planned for SP14 The suite shall not contain Pressure any components under ISS Safety SAF 5 vessel pressure ISS 5 Requirement Analysis Verification Verified No component specs require pressurization and all tests indicate no concern The suite shall not contain Ignition any active ignition sources ISS Safety SAF 6 sources or self igniting materials ISS 5 Requirement Analysis May 15 2014 16 831 SPHERES INSPECT Design Document 18 Verification Verified All currently manufactured components meet requirement The suite shall not contain any sources of ionizing or ISS Safety SAF 7 lonization non ionizing radiation ISS 5 Requirement Inspection Verification Verified Acceptance testing indicates no concern of ionization I
157. testing the board as outlined in previous sections to ensure that it was working as intended the board was attached to Halo via the 50 pin connector and attached to the ORF or ThermoCam using their respective May 15 2014 16 831 SPHERES INSPECT Design Document 111 connectors Because Halo did not route data on either the ORF or ThermoCam ports the sensors did not plug into the Ethernet connector on the MICPCBs instead routing data through an Ethernet switch and then to the VERTIGO Avionics Stack The MICPCB was tested to deliver power to the sensors and was found that it powered up both sensors and that they could transfer data through the Ethernet switch while routing power through the MICPCBs 6 2 5 1 MICPCB and Halo CL KAF The first step of integration is to connect the MICPCB to Halo without any other sensors or equipment and power Halo on to power the MICPCB This test will be conducted only after the MICPCB has passed the previous inspection and single component power tests This test will be carried out in the following steps and repeated twice once for the ORF PCB connected to the Halo Port 1 and once for the ThermoCam PCB connected to the Halo Port 5 1 Turn Halo off Connect the MICPCB to the Halo port as shown in Figure 89 2 Check for electrical shorts between ground and Batt and ground and Vout on the MICPCB 3 Turn Halo on As of May 2014 Halo ports do not have individual power switches so turning on Halo will prov
158. th this information the control law is then able to prescribe a desired torque on the satellite to be created by the CMGs This torque is passed to the CMG Mixer where it is converted into gimbal rates for each of the CMGs The current test configuration has this CMG mixer placed on VERTIGO as communication between SPHERES and VERTIGO has yet to be accomplished However once this is the case the CMG mixer could then be properly moved back onto SPHERES In the single axis of rotation case the four CMGs will act as scissor pairs This means that they will all change their gimbal positions to cancel all angular momentum components outside of the y axis The calculated gimbal rate is a non linear function as it depends on the current gimbal position of each CMG This data is requested from the Honeybee CMG Controller and returned to the GSP Once the desired gimbal rate is calculated it is then sent to the Honeybee CMG Controller through the UART port This data packet passes from SPHERES through the VERTIGO Avionics Stack though Halo through the CMG PCB and finally to the CMG Controller Board where it is implemented Once this occurs the inertial measurement unit updates the current state value of the system and the process is repeated VERTIGO CMG Communications Software HS A CMG control GUI was provided by Honeybee Robotics The GUI runs exclusively on Windows and is able to control CMG spin rates gimbal rates and gimbal positions via slider
159. the frequency can be changed following the guidelines in the INSPECT Interface Controls Document The image data is then transmitted to the VERTIGO Avioncis Stack via the buffer in the stream When the buffer reaches the stack streaming port the image data is retrieved from the buffer Using OpenCV the raw data array for each image frame is stored as an 80 x 64 matrix where each matrix element is a monochrome 8 bits unsigned int value for the corresponding pixel OpenCV is also used to open a window on a personal laptop connected to the VERTIGO Avionics Stack via the VERTIGO dongle and display the live stream of images being transmitted to the stack Each image is also stored on the VERTIGO SATA drive as a bitmap file Every image and raw data file is saved with a time stamp to millisecond precision After the image data is retrieved from the buffer the buffer is released and is free to acquire and transmit other image data blocks until the stream is commanded to close via key press The image data can then manually be transferred from the VERTIGO Avionics Stack to a personal computer via Internet or flashdrive May 15 2014 16 831 SPHERES INSPECT Design Document 72 4 1 4 7 To conduct a temperature analysis of an image the raw data had to be converted from a matrix of monochrome intensity values to one of temperature values In order to determine the conversion factor FLIR Tools software for Windows 7 was utilized Thermal images recorded fr
160. tion with Honeybee to facilitate F CMG VERTIGO software integration impacts understanding of CMG software ensure CMG May 15 2014 16 831 SPHERES INSPECT Design Document 100 Ensure wiring does not create irregularities in mass D EEN distribution that would impact navigational path 6 Likelihood Figure 83 System Risk Fever Chart Integration and Test 6 1 Assembly Procurement and Integration Plan GK Throughout February the structures team worked to finalize design plans including integration of the system mechanically and electronically to an air carriage while subsystems acquired all necessary hardware and began their first round of preliminary testing The ORF and ThermoCam were tested against vender specs and sensor requirements including field of view measurements Once these tests were accomplished and the VERTIGO team was familiarized with their system and its role in INSPECT the subsystems moved on to stack testing with the SPHERES and VERTIGO Avionics Stack to evaluate software and data transmission At the same time the systems integration team completed the preliminary system test to evaluate the maximum testing time on the flat floor based on calculations for the weight of the system and its ability to translate using SPHERES thrusters Upon completion of stack testing the subsystems were attached to the Halo structure in single component testing to test functionality and electrical and mechanical mounting prio
161. to support guest determine its pose in 2 scientist navigation dimensional space with 1 SX 1 algorithms Pose axis of rotation normal to SX 2 necessitates SEN 6 Sensors the test floor SX 5 navigational sensors Testing May 15 2014 16 831 SPHERES INSPECT Design Document 56 4 1 3 2 Design Choice MV The Optical Rangefinder selected for INSPECT is the MESA SR4000 The SR4000 is a phase shift time of flight camera INSPECT will use the Ethernet data wide field of view model of the SR4000 This choice was based on several factors chief among them being the kind of data that the device could return a 3 D point cloud without the need for gimbaling lack of extra development effort needed to return a 3 D view cost and power requirements The breakdown of this analysis may be found in Appendix B Subsystem Tradespaces Figure 40 MESA SR4000 Phase Shift Time of Flight Camera 7 The MESA SR4000 also provides data complementary to the VERTIGO system since it can return much more accurate depth data than the VERTIGO stereo system can These data can be brought together to form a 3 D map of the SPHERES s surrounding environment that is augmented by visual information from VERTIGO s cameras which will form a useful set of information for both navigation and inspection For traceability to SPHERES X it should be noted that the MESA SR4000 cannot operate in sunlight This means that this particular model will not work outside of the ISS However
162. to the Halo 50 pin port ERM8 025 09 0 S Connector DV K TR 9100 Resistor Resistor as part of health monitoring ESR18EZPJ91 1 system 51 kQ Resistor Resistor as part of health monitoring RC1206JR 0751KL system Diode Diode as part of health monitoring 1N4148WS May 15 2014 16 831 SPHERES INSPECT Design Document 48 system Gigabit Ethernet Connects to ORF and ThermoCam SS 7188V A NF Connector Ethernet cables for data transfer Switch Turns the MIC PCB on and off 21136NA 3 Hole Screw Connects MIC PCB to ORF and the 1771101 Terminal ThermoCam PNP Transistor PNP transistor as part of health 2DB1694 7 monitoring system LED Visual indicator when PCB is 597 3311 407F powered and when fuse has been tripped PPTC Fuse Current limited resettable fuse as 1812L075 24DR part of health monitoring system Voltage Regulator Step up 11 1V input from Halo to 12V S24SE12002PDFA required for ORF and ThermoCam H SAIT MARI 3 WOLTAGE_FEG ON OFF VOUT VOUT Figure 36 MIC PCB Testing Schematic CL CK May 15 2014 16 831 SPHERES INSPECT Design Document SCREN TERM Ti DIPHOENIX 49 mu O v D ber ETHERNET 29 VOLTAGE REG 597 3311 407F ON OFF VOUT MIN TRIM VOUT 56K Ohms 910 Ohm Tu 0 Ohm Figure 38 MIC PCB schematic with health monitoring system GP CL CK May 15 2014 16 831 SPHERES INSPECT Design Document 50 4 1 1 7 Software Ha
163. to the metrology data Specifically we observe across all tests a max error of roughly 30 cm with a RMS error of 4 cm A probability distribution which accurately encapsulates said properties can be used to draw samples from and subsequently add to the metrology data to simulate and therefore test the capabilities of in orbit GPS This would allow us to use the existing acoustic system as a proof of concept substitute in place of GPS 12 1 5 Incorporation GP To include GPS what would be required is the following Hardware e Antenna capable of receiving GPS signals Hardware filter able to handle Doppler shift and isolate proper frequencies Software e Software for time of flight calculations to determine position Extended Kalman Filter for state estimation from received signals Both of these pieces of software are already built into the SPHERES computer as they are used to correctly estimate their state using metrology data Additional software can be included to mitigate the effect of errors caused by distortions from the ionosphere Furthermore more advanced carrier based differential techniques could be used to improve accuracy The GPS would likely be made internal to SPHERES X hence not requiring power from Halo Along the same vein the GPS hardware would not mount to a Halo port and would use the May 15 2014 16 831 SPHERES INSPECT Design Document 138 SHERES X computer for calculations hence being disjoint from the VERTIGO c
164. ts Institute of Technology 2013 MESA Imaging SwissRanger SR4000 Online Available http www mesa imaging ch swissranger4000 php Accessed 28 Feb 2014 A Saenz Otero Design Principles for the Development of Space Technology Maturation Laboratories Aboard the International Space Station MIT Department of Aeronautics and Astronautics Cambridge 2005 D Miller SPHERES Flight Critical Design Review 15 Feb 2002 Online Available http ssl mit edu spheres library cdr SPHERES CDR Final pdf M T Vernacchia ORF Metrology Test Report MIT Department of Aeronautics and Astronautics 16 831 Class Cambridge 2014 D Sternberg Interviewee SPHERES exposure to Infrared Light Interview 3 March 2014 Flir User s Manual Flir Ax5 series Online Available http support flir com DocDownload Assets 86 English T559770 en US AB pdf Accessed 25 11 2013 eBUS SDK Programmer s Guide 17 September 2012 Online Available ftp 80 254 171 53 Pleora eBUS SDK 3 ebus sdk programmers guide pdf Accessed March 2014 Honeybee Robotics Quote for LEO H120 T50 CMGs Longmont CO 2013 Honeybee Robotics Draper CMG Array Command and Data Specification Honeybee Robotics Spacecraft Mechanisms Corporation 2014 D Hayhurst VERTIGO Goggles Avionics Stack ICD MIT Space Systems Lab Cambridge MA 2010 A R a M G U Tancredi Carrier based Differential GPS for autonomous relative navigation in LEO in A AA Gui
165. ture MV The time based architecture is somewhat simpler to implement However it requires a rigid imaging schedule and can cause the Metrology system to be down for longer than needed Further the timers will interrupt other processes possibly causing the delay of critical work Also during long missions the timers may drift out of sync MV The message based architecture allows the INSPECT software running on VERTIGO Avionics Stack to dictate a flexible imaging schedule This may be desirable if a mission wants to increase the imaging rate when it comes across an interesting feature Further the message based system will not drift out of sync and will likely be much more reliable Therefore the message based architecture is highly recommended over the timer based architecture MV Software KH MESA provides driver software for the Ubuntu Linux operating system which will be used to communicate with the optical rangefinder from the VERTIGO Avionics Computer As displayed in Figure 45 commands are sent from the VERTIGO avionics stack command port to the ORF The ORF is commanded by the VERTIGO Avionics Computer to take and transmit distance May 15 2014 16 831 SPHERES INSPECT Design Document 65 measurements at a rate of 1 Hz to the VERTIGO Avionics Computer where they are stored on the SSD via SATA in a format accessible by OpenCV which involves creating a Mat object to store the image information of the data matrix including the matrix
166. uminum mount structure Repeat steps 1 8 in section 6 2 5 1 Fully assemble the mount structure cage with the MICPCB still attached to the back plate Repeat steps 2 3 Attach the appropriate sensor to the mount structure Repeat the second half of the test steps 1 15 in section 0 6 2 5 6 MICPCB Halo Both Sensors in Mount Structures and Ethernet Switch CL KAF Verify that both MICPCBs function as expected and that the same results from section 6 2 5 4 are achieved when the ThermoCam and ORF are mounted to Halo simultaneously as shown in Figure 94 May 15 2014 16 831 SPHERES INSPECT Design Document 116 Figure 94 ThermoCam left and ORF right in their mount structures with MICPCBs connected to VERTIGO 6 2 6 6 2 7 6 2 7 1 Avionics Stack Optics Mount and Halo CL CMG Full Assembly Stack Testing Capability JS The CMG single component stack testing will require more structural support in order to orient SPHERES so that the Z axis is in the horizontal plane as required by our fully integrated testing system setup we make use of a SPHERES SLOSH inspired cradle better viewed in Figure 96 Full System Testing Structure This will allow SPHERES to rest on its side without blocking any thruster plumes This cradle will be press fitted into the cylindrical opening on the propulsion deck or the lazy Susan bench setup as seen in Figure 88 Finally in order to test the CMGs in the box 90 orientation we intend to use
167. ure connection with the corresponding female connector on Halo Port 5 To ensure that the mount does not cause any electrical shorts on the MICPCB spacers and or springs are placed between the heads of the screws and the Halo Port surface shortening the length of thread that protrudes through the other side of the port and mount face As an added protection the face adjacent to the MICPCB is covered with a layer of insulating kapton tape so that the metal leads from the board s through hold components do not come into contact with the aluminum surface of the mount Power and interfaces CL KAF The ThermoCam requires 12 V to operate which it receives from Halo Port 5 through the Samtec 50 pin connector interface with the MICPCB Halo provides 11 1 V unregulated to the Delta S24SE 12002PDFA a DC DC converter on the board which steps up that voltage to the May 15 2014 16 831 SPHERES INSPECT Design Document 69 required 12 V for the ThermoCam The ThermoCam will be connected to the MICPCB via a 12 pole M12 connector Figure 53 and Figure 54 that has been fitted with wires soldered to pins 1 and 2 only for power and ground The two wires will then connect from the M12 to the MICPCB through a 3 port screw terminal The ThermoCam requires a minimum of 1 1 A 13 2 W for start up and pulls an average of 0 25 A 3 W during steady state operation 11 3 Z 10 4 p 5 1 9 12 6 7 8 Figure 53 Pin assignment for M12 male connector m
168. us Items and Margin 0 5 0 5 0 75 Components Total 12 25 14 75 21 85 1096 Regulator Inefficiency 1 225 1 475 2 185 Grand Total 13 475 16 225 24 035 4 2 4 SPHERES On Board Processing MA In order to run the CMG control loops in real time the SPHERES CPU will be used to run the CMG control loops The CMG control loops need to run at 5Hz and will use the SPHERES PADS data In order for the stable attitude control of the INSPECT system to be possible the attitude controller must be able to accurately evaluate the spacecraft s orientation and rotation state at each cycle of the guest scientist program To do so the controller will pull the SPH RES current state from the internal IMU With these rotation parameters and the target parameters set by the test case the CMG attitude controller will be able to provide a desired torque to be sent to the CMG mixer In addition for the CMG mixer to be able to produce an appropriate gimbal rate for the desired torque the SPHERES CPU will need to pull the current state of each CMG to the guest scientist program This will include values for gimbal position in radians gimbal rate in radians per second and flywheel rate in RPM Each of these values will be used to calculate the angular momentum vector created by each CMG in the SPHERES coordinate system The sum of the four angular momentum vectors is what is used to determine the rotation of the spacecraft May 15 2014 16 831 SPHERES INSPECT Desi
169. verted to heat e Systems generate heat as uniform solids n worst case scenarios systems draw their maximum power continuously until failure The distance between Halo ports is sufficient to prevent individual subsystems from thermally affecting neighboring ones Method of Thermal Analysis NC MK To model the flow of heat through the components SolidWorks thermal simulation tools were utilized The simulation was performed using an ambient temperature of 295 K as this is the temperature in the ISS and using an assumption of non negligible convection as this is the environment during flat floor testing Although natural convection does not occur on the ISS forced convection via air currents would result in nearly the same heat loss NC Based on the power draw data in Table 36 the Optical Rangefinder ORF was the component of greatest concern The ORF and the Thermographic Camera ThermoCam use the same aluminum mounting structure detailed in Sections 4 1 3 3 and 4 1 4 3 which also serves as a heat sink The ORF specifications indicated an average power draw of 12W which is the power draw used in the analysis to follow It should also be noted that the average power draw measured after component delivery was found to be significantly lower at 4 64W so the thermal analysis conducted represents a worst case scenario Since the ThermoCam only draws an average 3W of power using the same mount a separate ThermoCam analysis from the ORF w
170. verters at 15 00 each plus standard shipping 2x5 pin In 4 Screw Out for CoreWind DLP USB232M G 100 00 4 converters at 25 00 each free shipping Module USB to TTL SRL UART Converter May 15 2014 16 831 SPHERES INSPECT Design Document 86 Vibration damping 34 08 16 stiff vibration dampers at 2 13 each Mounts 9378K13 Vibration damping 34 88 16 semi stiff vibration dampers at 2 18 each Mounts 9378K11 Vibration damping 36 00 4 flexible vibration dampers at 9 00 each Mounts 5822K4 1 1 4 screws 6 61 For reinforced enclosures one box of 100 screws Total Spent 287 38 Budget Remaining 89 4 4 2 Avionics and Communications 4 2 1 Data Interface LJ GP Figure 70 below displays the connection structure of the overall avionics and communications system Avionics Overall Avionics Outline Ethernet USB 2 0 Power UART 50 Pin Mm ORF PCB ThermoCam CMG Halo Port Halo Motherboard Figure 70 Avionics Outline JB Table 32 Subsystem Processing Summary Subsystem FLOPS 1 0 ee Time ud leede Thermographic Camera 0 002 0 0022 ORF 40 55 0 034 0 0374 VERTIGO 10 83 0 009 0 0099 Actuators 240 200 220 Localisation Algorithm 360 300 330 Total 653 84 545 600 May 15 2014 16 831 SPHERES INSPECT Design Document 87 The avionics box is connected to the various subsystems in INSPECT in order t
171. vionics Stack and Optics Mount with mechanical and electrical interfaces that support USB 2 0 and Ethernet connectivity allowing the addition of sensor components that can interact with SPHERES A discussion of Halo in the context of INSPECT may be found in Section 4 1 1 MK Figure 21 Halo Structure Pictured with SPHERES and VERTIGO Avionics Stack 3 May 15 2014 16 831 SPHERES INSPECT Design Document 32 As of May 2014 the Halo prototype in existence is fully mechanically functional allowing for all INSPECT sensors and actuators to successfully mount to their respective Halo ports The prototype is not electrically functional however as the power and data lines running throughout the structure are not complete Power is being successfully provided to all Halo ports except Halo Port 2 see Figure 30 meaning that the INSPECT sensors and actuators could be powered through Halo as planned Unfortunately due to delays with the Control Moment Gyroscope CMG subsystem the CMGs were not ready to interface for power with their designated Halo ports causing integrated testing to be completed with the CMGs being externally powered via a wall outlet The cable necessary for this modification is shown in Figure 22 the single black cable leading off in the bottom of the figure Figure 22 CMG External Power and Data Cables Data lines in the Halo prototype are only functional for HPG see Figure 30 as of May 2014 meaning that the INSP
172. ware system consists of Goggles Optics Mount API and Goggles Avionics Stack API and Goggles SPHERES API However VERTIGO Goggles software structure is mainly focused on Avionics Stack API As a core system for INSPECT Avionics Stack provides both hardware and two way command and receive software connections between SPHERES DSP and INSPECT peripheral imaging sensors The main functionalities include image processing and a pre emption of data inputs from VERTIGO Optics Mount ThermoCam and ORF The VERTIGO Goggles system also provides formatted sensor data to GSP via Goggles API Using these data guest scientists can prioritize the sensor inputs based on their own program of interest Data Capture Take color image Convert to grayscale Position timing calculation image Output three compatible images Calculate depth map Data Preparation i eh eg e wm Return Equalize resolution Ix y D G e of images assign pixel values Uniform FOV Uniform resolution 7 values per pixel image resolution TBD Image Alignment Figure 39 VERTIGO Avionics Stack Software Data Flow Diagram Figure 33 illustrates the data flow diagram specifically for the VERTIGO Optics Mount The Optics Mount goes through data capture data preparatation image alignment and GSP procedures For 16 83x INSPECT the major requirements were to implement and verify the data capture the data preparation and transfe
173. was also compatible with data verifying SX 2 SX 3 is on track to be verified by the printed circuit boards for health monitoring processes SX 4 was verified by software successfully saving to Sata drives 10 and 11 with support for future software integration 4 Sensor Analysis and Requirements Checks The accuracy of the Optical Rangefinder according to the data it obtained from the test and test board is shown below EN This meets the requirement SEN 2 as the system was successfully able to determine the range to the target the board and its varying depth stimuli accurate to within 0 1m and precision to 0 02m This was done at a distance 1 meter away from the board which is within the requirement of up to 7 meters away The error in measurement of the graph above is shown to be within the upper and lower bounds of the requirement shown in red dashed lines and through two different confidence intervals Below is a second graph supporting the standard of deviation to be within acceptable values for both the requirement and vendor specifications EN SEN 1 of the ORF was verified by measured specs of 56 degrees horizontal by 70 degrees vertical for field of view which is above the requirement of 33 degrees by 33 degrees The VERTIGO goggles also exhibited a field of view greater than necessary as shown in the following photo We The FLIR thermocamera measured a field of view of 47 5 degrees horizontal by 38 9 degrees vertical SEN 3
174. was verified by the VERTIGO goggles by obtaining an image of the at requirement 1cm square pattern of the test board and successfully being able to resolve the image as shown below ES SEN 4 was verified by the ORF as using 0 8 of the CPU and 0 3 of the RAM at 96 3 kBps of the Avionics stack The following chart shows these values again the imaging frequency May 15 2014 16 831 SPHERES INSPECT Design Document 126 EX All are acceptable values and the requirement is verified for the ORF By similar reasoning the thermocam also fulfills the requirement by the chart shown below with CPU usage of 2 1 and RAM 1 2 es The data rate of the thermocam was 10 kBps which shown below and is at a rate that can be processed by the Avionics stack so no external computer is necessary for processing and the requirement is verified e des The thermocamera was able to resolve a thermal image from the thermal pads on the test board from 1 meter away to 5 degrees Celsius accuracy and less than 1 degree precision verifying SEN 5 Below shows the images the thermocam recorded of the test board Gel 1 and 3 dictate the at requirement 5cm by 5cm plates and 2 and 4 are the above requirement 4cm by 4cm plates x ES EN The above chart shows the measured values from the thermocouple versus the error of the measurement from the sensor All values are within the upper and lower bounds of the requirement e EN The standard deviatio
175. whenever the SPHERES IR receivers detect IR light above a threshold intensity If the SPHERES satellite is constantly illuminated with IR light the IR Rcv interrupt will be triggered so rapidly that other processes on the DSP will be starved of processor time Particularly the Fast Housekeeping timer based interrupt will be blocked from executing see Figure 44 If the Fast Housekeeping tasks are not performed at the nominal interval a watchdog process will reset the DSP 8 When a SPHERES satellite is continuously illuminated with IR light the IR Rcv interrupt starves the Fast Housekeeping and the SPHERES resets its DSP over and over again without performing any useful computation 11 10 MV E E i gd 5 zi A m OTT FA 5 PESTE 2205 zi E H IOS o pointe 8 d Fast Housekeeping S DRE E SZ eee SE Se S i Figure 44 The highest priority interrupts in the SPHERES DSP software architecture 8 Even if the ORF is not illuminating a SPHERES satellite the constant operation of the ORF severely degrades the accuracy of the Metrology system see Figure 45 Thus the ORF cannot be operated in continuous acquisition mode when used in INSPECT MV May 15 2014 16 831 SPHERES INSPECT Design Document 61 No of occurences No of occurences 1500 1000 500 1500 1000 500 ORF Off 1 1 0 1 0 2 0 3 0 4 0 5 0 6 0 7 Position Error m 0 8 0 9 1
176. x y plane sise 123 Figure 100 Profile area in y z plane usines 123 Figure 101 Unified Printed Circuit Board v1 JB CK nennen 142 Figure 102 Unified Printed Circuit Board v2 JB CK nnne nennen 143 Figure 103 Unified Printed Circuit Board v3 JB CK nennen nennen 143 Figure 104 Unified Print Circuit Board v4 JB CR 144 Figure 105 Unified Print Circuit Board v5 JB CR 144 Figure 106 Multiple Interface Connector MIC Printed Circuit Board v6 CL NM 145 Figure 107 Multiple Interface Connector MIC Printed Circuit Board v7 CL 145 Figure 108 Multiple Interface Connector MIC Printed Circuit Board v8 CL 146 Figure 109 Multiple Interface Connector MIC Printed Circuit Board v9 CL 146 Figure 110 Multiple Interface Connector MIC Printed Circuit Board v10 CK CL GP 147 Figure 111 Multiple Interface Connector MIC Printed Circuit Board v12 CK CL GP 147 Figure 112 Multiple Interface Connector MIC Printed Circuit Board v12 CU 148 Figure 113 Multiple Interface Connector MIC Printed Circuit Board v13 CL GP 149 Figure 114 Multiple Interface Connector MIC Printed Circuit Board v 14 CL GP 150 Figure 115 Multiple Interface Connector MIC Printed Circuit Board v17 CK CL GP 150 Figure 116 Screw terminal used on the MIC PCB cust
177. xclusion is further justified by the fact that the information required for position and attitude determination and control is negligible compared to though higher priority than the information being transferred for the imaging sensors This analysis revealed that in the 1Hz case if each sensor were to return a single image per cycle the total amount of time required would fit well within the cycle period even if all operations were blocking which they do not have to be and the Avionics Stack had to wait on each sensor every time Table 34 Worst case timing analysis Component Operation Time Needed ms May 15 2014 16 831 SPHERES INSPECT Design Document 92 SPHERES PADS Thrusters 400 CMGs 10 ORF Expose CCD 20 Read Download CCD 50 Transfer data 43 ThermoCam Expose CCD 12 Read Download CCD 50 Transfer data 0 72 VERTIGO Goggles Expose CCD 20 Read Download CCD 50 Transfer data 150 Total Time 255 72 PADS Thrusters time is for SPHERES only and is excluded from Avionics Stack timing Time required to read and download CCD values is unknown unclear from documentation whether the values given for operation time include this period so a 50 ms value was included for each one assuming that hardware performance was proportional to the amount of data to be read off on off state Worst case Delay Times for 1Hz Operation 100 200 3
178. y Bee this is the main component to which all others will attach It is the housing for the drive electronics The hole pattern includes 4 threaded holes in a square pattern that will be the mechanical interface to attach to the swivel plate as seen in Figure 60 Honey Bee Control Box Top View along with 10 0 136 mm holes and cylindrical standoffs to accommodate the CMG PCB hole footprint as shown in Figure 61 0 50 Figure 60 Honey Bee Control Box Top View May 15 2014 16 831 SPHERES INSPECT Design Document 77 Figure 61 CMG PCB Dimensions and Hole Layout in 4 1 5 3 2 Swivel Mounting Plate This is the plate to which the enclosed CMGs will directly attach It contains 16 7 32 inch holes in a hexagonal pattern surrounding the large cut outs for the CMG retainer This is what will give the assembly the ability to accommodate both control configurations May 15 2014 16 831 SPHERES INSPECT Design Document 78 8 750 Figure 62 Swivel Mounting Plate 4 1 5 3 3 CMG Mounts with Captive Screws The CMGs will be directly mounted on this component via 4 6 32 tapped holes and screws This component will attach directly to the swivel mounting plate via the 4 7 32 for 4 socket and captive screws and be constrained to the swivel plate plane by the CMG retainers Figure 63 CMG Mounting Plate Drawing 4 1 5 3 4 CMG Covers JS JK Necessary for safety this component will enclose the flywheel a
179. y by our system are 1 Sensor specifications 2 Blur requirements 3 Acceleration limits 4 System inertial and mass The mass of our system is such that accelerating between images would be trivial to the overall speed of the system Following this constraint the system shall accelerate to a drift velocity set forth by the blur requirement and maintains that speed until all images have been taken Figure 11 through Figure 18 show the inspection maneuvers necessary to carry out a complete inspection maneuver Maneuvers 1 3 carry out the pure translational phase of the inspection Maneuvers 4 and 5 transition system to the initial state for the pure rotational phase and Maneuvers 6 8 carry out the pure rotational phase May 15 2014 16 831 SPHERES INSPECT Design Document 27 Maneuver 1 First image and linear acceleration to drift velocity 2m Figure 11 Maneuver 1 Maneuver 2 Translational imaging sequence Figure 12 Maneuver 2 Maneuver 3 Linear deceleration May 15 2014 16 831 SPHERES INSPECT Design Document 28 2m Figure 13 Maneuver 3 Maneuver 4 Rotation 2m ge e de s Figure 14 Maneuver 4 Maneuver 5 Translation to rotational inspection position 2m T Figure 15 Maneuver 5 Maneuver 6 Acceleration to rotational drift velocity May 15 2014 16 831 SPHERES INSPECT Design Document 29 2m 1 L og LD Figure 16 Maneuver 6 Maneuver 7 Rotational inspectio
180. y connected to a Halo using USB 2 0 or Verification Ethernet via HPG Each suite component shall Each Halo port operate with no more than provides 11 1V ata 16 65W and be able to convert maximum of 1 5A operational current voltage from before tripping a H 3 Power 11 1V 1 5A S 4 breaker Analysis Verified All subsystems have interface boards to convert voltage and operate within Verification power limit The suite shall not impose a Friction mount is not force greater than 40 N in the Z meant to operate H 4 Force Limit direction to SPHERES S 4 above this force Analysis Verified Analysis shows 79N force in Z direction which was compensated for by adding supports to the testing structure to support Halo decreasing total force on Halo to less Verification than 10N SX Navigation INSPECT shall provide a M 1 Needed to fulfill Analysis May 15 2014 16 831 SPHERES INSPECT Design Document 16 1 functional API for localization mission goal properly and mapping test the system Verified Software data alignment successful and data output in format compatible with Verification standard autonomous SLAM protocols INSPECT shall provide a Needed to fulfill functional API for identification mission goal and SX and description of observable properly test the 2 Inspection objects M 1 system Analysis

Inspect Design Document - MIT Space Systems Laboratory

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