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SPECTRE Testing Readiness Review

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TRR Overview Customer:Advisor: Dr. Keats Wilkie Dr. Xinlin Li NASA LangleyDepartment of Aerospace Engineering Sciences, CU LASP SPECTRE MSR Project Overview Justin Schedule Justin Testing: Motors Corinne Testing: Sensing Chris Testing: Damping Kyle Budget Status Kyle 2

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Heliogyro Background Experimental onboard spacecraft propulsion system Uses high aspect ratio blades that generate thrust from solar radiation pressure Blades are held in place by centripetal acceleration of spinning spacecraft bus Has advantages to traditional solar sails Blades can be pitched for more complex maneuvering No heavy support structures necessary 3

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Project Background No heliogyro system has ever been flown since first proposed in the 1970s NASA in interested in demonstrating the first heliogyro on a 6U CubeSat platform SPECTRE is designing a control system which will demonstrate the ability to 1 ) Pitch blades over a +/- 90 degree range relative to a satellite bus 2) Demonstrate the ability to augment damping flapping and pitching modes of the blade 2 Blade 6U CubeSat Design: Dimensions 10cm x 20cm x 30cm Housing Bus 4

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Blade Oscillations Blade Root Blade Tip Housing flap Nominal Blade Deflected Blade Flapping twist Blade Root Blade Tip Twisting 5

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CPEs and Levels of Success Critical Project Elements Control Law Software Matlab GUI, control law Motors Linear and rotary actuators Image Processing Sensing Raspberry Pi, image processing algorithm, camera, markers Electronics Arduino Due, Raspberry Pi, motor drivers, interfacing 6 Success LevelCriteria 1Pitching to commanded angle of 90 within 5 2 3

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FBD Blade HousingCubeSat Bus Power Supply MatLab User Interface Rotational Actuator Linear Actuator Camera LED Raspberry Pi Arduino Due Actuator Drivers Mode, Angle, Rate (UART) Images Voltage RS232 instructions Angle, Logic (UART) Blade Linear Motion Pitching Motion Legend: -Power -Data -Commands -Motion 6 V 5 V 9 V >1 V 1.8 V 8

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Control Law block diagram cc + Derivative control PD- controller Actuator Plant Pendulum or Membrane ladder Plant Tip Deflection Camera Resolution Transport Delay - 9

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Control Law block diagram cc + Derivative control PD- controller Actuator Plant Pendulum or Membrane ladder Plant Tip Deflection Camera Resolution/ Measurement Error Transport Delay - Arduino Due/ User Interface Motor Drivers Heliogyro Blade Sensor (Camera) Image Processor 10

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Design Changes Since MSR New bevel gear has been selected that will be easy to modify while retaining structural integrity (acetal plastic) Image Processing board switched from Overo FireStorm to a Raspberry Pi Could not get Caspa VL to communicate with the FireStorm Software/Electrical progress remains on schedule 11

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Project Schedule

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Progress Since MSR Manufacturing/Mechanical All housing and bus components machined All planned purchases have been made Motor Driver integration complete Software/Electrical Camera/Image processing interface complete Image processing algorithm completed and tested User interface completed Motor Controller/MatLab integration complete 13

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14 SPECTRE Schedule Spring Break Week 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 MSR TRR

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Spring Break 15 SPECTRE Schedule: Milestones All controller components made/received Image Processing Code Written and Tested Damping Testing Can Begin Week 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Control Loop Timing Can be Tested

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16 SPECTRE Testing Schedule TestsDurationStart DateEnd DateStatus Sensor Testing2 weeksFebruary 14February 28Complete Motor Testing3-4 weeksFebruary 18March 11-18In Progress Damping Testing2-3 weeksMarch 30April 10-17Pending Tasks remaining before damping testing can begin Integration of image processor board and motor control board Installation of motors, drivers, control boards Completion of motor testing 3-4 weeks total

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Testing Readiness

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Testing Scope cc + Derivative Control PD-Controller Actuator Plant Pendulum or Membrane Ladder Plant Tip Deflection Camera Resolution/ Measurement Error Transport Delay - Arduino Due/ User Interface Motor Drivers Heliogyro Blade Sensor (Camera) Image Processor 18 System Tolerances to Achieve Proper Damping Total Transport Delay

Sensor Testing: Systematic Error 25 Blade Remains in 0 twist and flap unperturbed position. Output from image processing algorithm is sampled Mean Systematic Error: 2.65 1.88 times smaller than maximum 5 Systematic Error could be further decreased by using high accuracy (> 1) level tools when mounting the controller Measured centroid locations Boundary of maximum allowable systematic error Mean distance to center pixel: 17.5 pixels=2.65

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Sensor Testing: Random Error 26 Mean Random Error: < 0.14 7x smaller than 1 maximum Actual noise is even smaller since blade small amplitude flapping oscillation is still present Test setup is not exposed vibrations that would disrupt controller operation Marker Centroid Position During Testing Marker x coordinate vs. Time

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Sensor Testing: Oscillating Blades 27 Sampling Rate: 12.5 Hz 3.13x faster than 4 Hz requirement Algorithm outputs deflections consistent with expected blade behavior for both modes Camera captures full range of motion of both modes Measured Twist Angle vs. Time Measured Flap Angle vs. Time

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Damping Testing 28 Most important testing for verification and validation of the controller Completion will validate all project success levels Housing assembled with deployed blade with LEDs in dark environment Modes of the blade are excited manually (tip mass is released in pendulum motion) Sensing measures deflection angles until oscillation stops without motor actuation Control loop switched on, Modes excited manually and damped Damping Ratios calculated, controller damping found by subtracting air damping

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Damping Testing Setup 29 Camera FOV Test Stand Frame ~2.5 meters 2 meters Housing Blade Markers 2 meters 1 meter Power Supply User Interface Surface area under camera covered with black, light- absorbing materials No Special testing facilities are needed

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Control Law Expected Performance Twisting Mode Flapping Mode 30 Twisting ModeFlapping Mode Damping ratio without control law (Air damping only)0.00550.0050 Damping ratio with control law (Controller and air damping)0.01320.0200 Damping ratio predicted (air damping is subtracted) 0.00770.0150 Damping ratio required 0.00730.0136

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Budget

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Component:Number Needed: Lead Times (Weeks): Cost per Component: Total Price: Overo Firestorm/Pi1Received$232.00 Pinto1Received$ 27.50 Power Adapters2Received$ 10.00$ 20.00 Caspa VL1Received$ 75.00 Micro SD1Received$ 50.00 Arduino DUE1Received$ 50.00 USB Cable3Received$ 3.00$ 9.00 Linear Motor1Received$690.00 Linear Motor Driver1Received$226.00 Rotary Motor1Received$220.00 Rotary Motor Driver1Received$226.00 LEDs2Received$ 10.00 Aluminum Sheet1Received$ 50.00 Misc. Wires1Received$100.00 Misc. Screws1Received$100.00 Rotary Encoder1Received$ 50.00 Hardened Steel Shaft1Received$ 24.00 Linear Bearing with Pillow Block 1Received$ 40.00 Shaft Support2Received$ 44.00 Bevel Gear1Received$ 50.00 Turntable Bearing1Received$ 5.00 Radial Berings1Received$ 5.00 Precision Shaft (hollow)1Received$ 40.00 Mounting Components1Received$ 40.00 TOTAL$ 3015.60 33 Additional Purchases Raspberry Pi + Camera Module ~$75 Additional Arduino Due Board ~$60 2 RS232 shifters replacement ~$35 Additional Bevel Gear ~$30 ~$200 Budget Breakdown

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Backup Slides

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Testing Requirements Functional RequirementsTesting MethodsTesting Status Controller housing must be able to accommodate one blade capable of providing the spacecraft with a 0.1 mm/s ^2 acceleration By Inspection-- Controller must be able to pitch blades to 90 with 5 of accuracy Motor TestingIn Progress Blade Damping TestingPending Controller must be capable of sensing blade deflections without an ambient light source Sensing TestingIn Progress Controller and blade occupy 2U of volume (10cm x 10cm x 20cm) By Inspection-- Controller must run on approximately 5 watts of power By Inspection-- Controller must conform to Cubesat weight requirement ~1.3 kg/U, total of 2.6 kg By Inspection-- 35

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MatLab GUI 36

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Motor Test - Software Flow Matlab uses the predicted blade position as input to the control law. Motor commands are generated and passed to the Arduino over Serial USB. Arduino receives the commands, and relays the information over Serial TTL to the converter. The data is then converted to RS232, and passed to the motor driver. The motor driver interprets the command and moves the actuator. A logic analyzer is used to receive position data from the motor driver. Command X MATLAB Converter Driver Serial USB Serial TTL Serial RS232 Command X Logic Analyzer Position DataPulse Generator Arduino

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Control Law input Blade Position and Angular Velocity Currently using input data from predictive model MATLAB uses the simulation run time at each iteration step to interpolate the dataset, as if it were receiving real-time data. Control Law output Root (Angular) Position If control law is active, uses derivative gain to calculate the required root position Motor command is constructed and sent to the Arduino over Serial output. Commands sent every 0.09 seconds INPUTS OUTPUT

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39 Margin: $1,984.40 All planned purchases have been made

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Image Processing Algorithm 40 Filter Applied Y < 212 Cr < 100 Cb < 100 RGB YCbCr (0,0, 0) (255,255, 255)

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Motor Testing Outline 41 Motors Connected To Drivers Drivers Connected To User Interface Motor are commanded to move as predicted by the Simulink model Driver Encoder output used to track motor position over time, calculate rates and errors Motors are connected to CubeSat, and process is repeated Driver RS232 Adapter Arduino Due Logic Analyzer (records driver encoder output) MatLab Connection Motor Connection Both motors are testing while outside of the housing to test software interfacing, and while installed in the housing to test errors induced by friction, mechanical interfacing

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42 Leveled with small circle level to within 5 degrees (for error requirements) Clamped to ladder tops Ground Wooden Test Stand Frame 2.5 meters 2 meters Housing Blade Markers 2 meters Ladders from http://imgkid.com/wooden-ladder-clip-art.shtmlhttp://imgkid.com/wooden-ladder-clip-art.shtml 1 meter

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Component:Number Needed: Lead Times (Weeks): Cost per Component: Total Price: Overo Firestorm-P13$159.00 Pinto13$ 27.50 Power Adapters23$ 10.00$ 20.00 Caspa VL13$ 75.00 Micro SD10$ 50.00 Arduino DUE16-8$ 50.00 USB Cable30$ 3.00$ 9.00 Linear Motor13$690.00 Linear Motor Driver18$226.00 Rotary Motor13$220.00 Rotary Motor Driver16-8$226.00 LEDs20$ 10.00 Aluminum Sheet11$ 50.00 Misc. Wires?0$100.00 Misc. Screws?0$100.00 Rotary Encoder13$ 50.00 Hardened Steel Shaft11$ 24.00 Linear Bearing with Pillow Block 11$ 40.00 Shaft Support21$ 44.00 Bevel Gear11$ 50.00 Turntable Bearing11$ 5.00 Radial Berings11$ 5.00 Precision Shaft (hollow)11$ 40.00 Mounting Components11$ 40.00 TOTAL$ 3051.60 Current Expenditures $3051.60 All parts have been purchased Margin $1984.40 Margin is sufficient to repurchase any component if needed 43