MSR Team SAVI. Satellite Active Vibration Inverter

Transcription

1 MSR Team SAVI Satellite Active Vibration Inverter Wasseem Bel Patrick Byrne Blake Firner Corey Hyatt Joseph Schmitz Justin Tomasetti Jackson Vlay Benjamin Zatz

2 Project Purpose Cryocoolers create Exported Forces and Torques (EFTs) Frequencies dynamically range from 40 to 60 Hz Amplitudes on the order of 20 microns (twice the thickness of a sheet of paper) Simulated Telescoping Camera Payload 22 kg mass 1 rad Pixel Resolution Image Smearing Pixel Movement Angular Displacements from EFTs These EFTs will cause up to 150 pixel smear 1- Cryocooler 2- Simulated camera payload 3- SAVI system Develop a Satellite Active Vibration Inverter (SAVI) mount system that will identify and cancel low frequency vibrations from a cryocooler that cause image smearing on a telescopic camera

3 SAVI and Test Stand Details SAVI 2 Actuating Legs Top Plate Solid Leg Flexures placed on top and bottom of actuating legs to avoid shear stresses in piezoelectric actuators Accelerometer Base Plate Flexure Flexures placed on top of solid leg to allow for plate rotation 2 Solid Legs Top Plate Base Plate Actuating Leg Test Stand Accelerometers placed on top plate next to each leg and on bottom plate next to the two actuating legs 3

4 Levels of Success Level 1: Pixel smear reduced by 60% to about 60 pixels of smear Level 2: Pixel smear reduced by 80% so that about 30 pixels or fewer are smeared Signal frequency has dwell time of 2 seconds Level 3: The system dimensions will not exceed 20 cm x 20 cm x 10 cm The system mass will not exceed 5 kg The system will use no more than 10 W of power 4

5 Critical Project Elements Flexture Longitudinally rigid Laterally flexible Mitigates shear stresses on Actuators Epoxy Soluble Be able to bond all materials Negligible vibration damping in compression Modal Analysis Modes must not exist in Hz range DAQ Error Possible aliasing Amplitude error is frequency dependent 5

6 Updates Accelerometer Calibration Previously mentioned drop test in FFR has been discarded Cannot be statically tested for accuracy Borrowed accelerometers are being sent to PCB Piezotronics to be recalibrated Recessed mount holes for struts on plates Improved alignment of the struts (accuracy is critical) Allows for increased flexure size -> Resonance modes of system are distanced from the operating frequency range A laser will be used to verify the full system Tests will be done at Ball Aerospace -> new noise test data is needed 6

7 of Major Milestones 7

8 Technical Breakdown 8

9 SAVI Communication 9

10 Early Electronics Integration 10

11 Plans for Final Circuit Two PCB boards stacked PCB Board 1 (Left): 2 Banana clip panel mounts 3 BNC surface mounts PCB Board 2 (Below) 5 Resistors - 860Ω 5 Capacitors 2.2μF 5 BNC surface mounts 11

12 Software Recap After Fall semester, many of the technical software elements were completed including: EFT wave determination routines Wave inversion and output Simulink Model predicting software performance. What needed further development: Interfacing with electronics Continuous DAQ input and output to capture accelerometer data and drive actuators, respectively. Real time computation of prediction wave using real sensor data To PDm s From C65 s 12

13 Software Development Software/Electronics Interfacing Developments: Input and output infrastructure complete Software now capable of electronics integration with the following capabilities: Account for individual electronics calibration and varying sensitivities of parts Generate arbitrary output disturbance in real time Acquire accelerometer data in real time Compute EFT from accelerometer data in real time 13

14 Software and Electronics Demonstration To demonstrate software and electronics capabilities: Constructed demonstration consisting of: Software cdaq with NI-9263 and NI 9205 PDm200 Unloaded piezo-electric stack C65 Accelerometer Purpose is to demonstrate: Continuous voltage output Properly drive Piezo-electric stack disturbance up to 100V Continuous sensor input Sense micron level vibrations Real time calculation of EFT prediction using real accelerometer data being driven by micron level piezoelectric stack displacements. C65 PDm200 Actuator NI-9263 cdaq NI-9205 Signal Conditioner 14

15 Demonstration Results EFT prediction created in real time using accelerometer data. Tracking of frequency prediction during a frequency sweep Adjustment to a change in EFT disturbance in 1 8 dwell time 15

16 Demonstration Issues Sampling rate of the DAQ affects amplitude of the acceleration data it records Frequency is unaffected Sampling frequency must be at least 16kHz to achieve desired actuator displacements Sampling Rate: 4096 Hz Sampling Rate: Hz 16

17 Top and Bottom Plate Changes in design: Small pockets created on all plates to assist in vertical alignment Depth: cm Diameter: 1.27 cm Flexures and legs will be epoxied into holes Manufacture: Generated SolidCAM code for CNC mill to machine top and bottom plates Edges sanded for smooth surface Manufactured top and bottom plate 17

18 Cyberbond Apollo 2150 Leg to Flexure Connection cm Leg to Plate Connection cm Plate to Plate Connection cm Surfaces will be treated and sand blasted in order to maximize bond strength 18

19 Flexures Flexures to be manufactured with CNC Lathe Lathe was inoperable due to wrong parts New parts have been installed and machine is almost operational. Flexures should be machined this week Due to the hole recession of the plates, the flexures were able to be increased in length 2.26 cm cm 1.27 cm cm cm 19

20 Flexures Test Compression/Tension Moment Structure SAVI Test Stand SAVI and Test Stand Force Applied (N) Max Stress (N/m 2 ) Max Displacement (μm) Moment applied (N-cm) n/a n/a n/a n/a 0.5 Fixed Geometry Compression Tension Simulated Moment Maximum moment the actuator tips can handle is 8.0 N cm Largest manufacturing tolerance was used when calculating the corresponding needed deflection of the flexures 20

21 Modal Analysis SAVI and Test Stand Mode Frequency (Hz) and Bandwidth Description ±0.103 Top plate of SAVI pivoting about solid leg in the horizontal plane ±0.270 SAVI and Test Stand swaying from side to side (Base Fixed) ±0.286 SAVI and Test Stand twisting back and fourth (Base Fixed) ±1.106 Center Plates moving side-to-side in the Horizontal Plane ±1.149 Center Plates moving side-to-side in the Horizontal Plane (60 degree shift) 21

22 Financial Layout Item Quantity Item Cost ($) Shipping ($) Total Item Cost ($) PDm P Laser and Safety Goggles Building Material: Plates, Rods and Simulated Mass AE0505D16F Actuator Extra Plates Replacement Plates Misc. Supplies Remaining Total Cost $ $

23 List of Components Items Received Building materials: Plates, Rods and Simulated Mass PDm200 Drivers AE0505D16F Actuator Items Awaiting Delivery P Actuators Laser and Safety Goggles Items Not Yet Ordered Epoxy and Solvent 23

24 Backup Slides 24

25 Critical Project Elements Data Input and Output from MATLAB Interface NI CompactDAQ Capable of communicating with MATLAB Queued data I/O directly into MATLAB For maintaining a processing speed to mitigate output signal phase error Characterize 20 μm EFT Vibration Find frequency (f), amplitude (A) and phase (θ) from noisy accelerometer data Accelerometers Actuators Collected errors in frequency, phase and amplitude must meet residual requirements PCB C65 Piezoelectric accelerometer Must be able to measure system level vibrations PI Piezoelectric actuator Actuator Driver Must be able to have submicron resolution while under the payload PDm200 Voltage amplifier and signal conditioner Must be able to run actuator within specifications Must be compatible with DAQ system NI CompactDAQ with modules Structural Analysis NI 9205 Analog to digital voltage measurement Must be able to sample system level vibrations NI 9263 Digital to analog voltage output Flexure Must be able to provide input voltage to PDm200 Longitudinally rigid and laterally flexible to allow flexibility and mitigate shear stresses Base/top plate and solid leg Sufficient stiffness to be approximated as a rigid element Electronic components Electronic mounting capability Connections Materials compatible with epoxy chosen Modeled in CAD (SolidWorks) Able to produce force and vibration analysis Able to confirm flexure deflection with system loads 25