Drexel RockSAT Full Mission System Testing Report

Kelly Collett • Christopher Elko • Danielle JacobsonApril 24, 2012

FMSTR Presentation Contents

• Section 1: Mission Overview• Mission Statement• Mission Objectives• Expected Results• System Modifications• Functional Block Diagrams

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FMSTR Presentation Contents

• Section 2: Subsystem Test Reports• Subsystems Overview• Structural System (STR)• Piezoelectric Actuator System (PEA)• Electrical Power System (EPS)• Visual Verification System (VVS)

• Section 3: Conclusions• Plans for Integration• Lessons Learned

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Mission OverviewDrexel RockSat Team 2011-2012

Mission Statement

Develop and test a system that will use piezoelectric materials to convert

mechanical vibrational energy into electrical energy to trickle charge on-board power

systems.

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Mission Overview• Demonstrate feasibility of power generation

via piezoelectric effect under Terrier-Orion flight conditions

• Determine optimal piezoelectric material for energy conversion in this application

• Classify relationships between orientation of piezoelectric actuators and output voltage

• Data will benefit future RockSAT and CubeSAT missions as a potential source of power

• Data will be used for feasibility study

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Expected Results• Piezoelectric beam array will harness enough

vibrational energy to generate and store voltage sufficient to power satellite systems• Anticipate output of 130 mV per piezo

strip, based on preliminary testing.• Success dependent on following factors:• Permittivity of piezoelectric material• Mechanical stress, which is related to the

amplitude of vibrations• Frequency of vibrations

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Changes Since ISTR

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• Implemented latching relay for g-switch• Added additional 9V battery to power camera

Mechanical SubsystemsChristopher Elko

Integration full payload

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Integration PEA & STR

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• All PEA subsystem components fit successfully on lower flight deck

• No interference with VVS components• Electronics fit successfully on upper flight deck

Physical Specs full payload

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• Overall Height: 4.5 inches• Overall Weight (including electronics): 2.42 lb• CG: X = -0.01, Y = 0.27, Z = 0.10 in.

Canister Sharing with Temple• Method of Integration: standoffs• Min. Required Standoff Clearance: 1.0 inch• Combined Weight: 7.06 lb (based on designs)• Combined CG: pending final designs from

Temple• CG to be adjusted with systematic ballast placement

Prepare for Takeoff

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• Written integration procedure: in progress• Full parts list: compiled• Spare parts: procurement in progress

Action Items• More regular interface with Temple• Final construction of BETA

EPS and SoftwareDanielle Jacobson

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PEA I

Camera

Rectifier + Capacitor

PEA II

Rectifier + Capacitor

Accelerometer II

Rectifier + Capacitor

Rectifier +Capacitor

PEA III PEA IV

Electrical Design

9V Battery G-SwitchWallopsNew / updated part

InternalMemory

LED Array

9V Battery

SD CardMemory

Accelerometer IArduino

Microcontroller

Power connectionData connection

Legend

EPS test summary

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• All electronics performed favorably• Integration went smoothly• Activation system still in need of latching

relay• Mechanical solution introduces a troubling

single point of failure• Once activated, closes circuit until reset• Currently on order

Data as collected

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A bit messy…let’s take a closer look…

Conclusion

Data piezoelectric output

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Pendulum beam generates highest voltage followed by diving board orientation; balance beam lowest (low G’s?)

5V Reference Input

Observations

Data accelerometers

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High-load vibration testing needed to fully characterize correlation between voltage output and acceleration (Wallops)

Conclusion

Data correlations

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As acceleration in beam oriented direction increases, generated voltage also increases!!! It works!!!

Z-Axis Acceleration

Observations

Battery Power

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• Before full system test: ~ 9.3 V• Voltage after full system test: ~ 8.1 V• ΔV over 30-minute test: ~ 1.2 V• Estimated operation time until failure: 1.5+

hr

Software

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• Software is running as planned• Data collection rates are solid• No inconsistencies

VVS UpdatesKelly Collett

VVS status update

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VVS on a serious note…

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• Camera wired to 9V Battery• Originally running from

Arduino 5 V output• Moved so Arduino can

have its own power source

VVS test summary

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• Camera will not function on auxiliary battery• Works when hooked up to the Li-Ion battery,

but not the 9V• Odd, since it worked with the 9V power

supply during ISTR testing

VVS troubleshooting

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• Attempted changing resistors in the voltage regulator circuit• Resistor ratio (R2/R1) = 1.96

• 2.2/1.2, V = 3.7 V (It worked this time!)• 3.5/1.5, V = 4.5 V (It worked for a little while this

time)• 7.35 / 3.7, NOTHING

• Voltage going into circuit is too high?• 9 V, perhaps drop to 5 V?

• Currently coming out of circuit at 4.5 V or higher

Conclusions

Action Items

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STR & PEA• Finish any machining for BETA supports, mounts, etc.• Laser-cut BETA decks• Reconstruction – estimated completion date: 4/29/2012

EPS• Vibe testing at Wallops to determine actual accelerations

from test data • Latching relay to be integrated this week; clean up wiring

VVS• Don’t burn the camera…yet• Determine voltage issue

Integration• Communicate with Temple…

Issues and Concerns

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• Camera• Latching relay• Spotty communication with Temple

Final Thoughts

Acknowledgements• Kyle Dooley for assistance with electronics and

circuitry troubleshooting• Dan Lofaro for lending us his precision solder

kit

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Thank you!Questions?