atellite ctive ibration nverter

Single Pixel SmearObject

pixel1 pixel2 pixel3

SAVIP820.20

Actuators

Accelerometer

Solid Leg

Top Plate

Base Plate

Top Plate

Base Plate

P176.50Flexure

Test Stand

Solid Leg

P176.50Flexure

Mass

P820.20 Actuator

ObjectiveTo develop a mount system that will identify and mitigates low frequency vibrations from a cryocooler that cause image smearing on a telescopic camera.

Project DetailsCryocoolers create Exported Forces and Torques (EFTs)•Frequencies dynamically range from 40 to 60 Hz •Amplitudes up to 20 microns

Image Smearing •Pixel movement caused by angular displacements from EFTs

These EFTs will cause up to 150 pixel smear

Levels of SuccessTier 1: Reduce image smear by 60%Tier 2: Reduce image smear by 80%Tier 3: System is no larger than 20cm x 20cm x

10cm, its mass is less than 5kg, and its power draw is less than 10 W

Time Budget

EFT Determination

Collect Data

Compute

Actuate

• The manufactured flexures are designed such that the moment acting on the actuator does not cause the actuator tip to shear off

• The flexures on the top and bottom of the actuating legs avoid damaging shear stresses in the actuators

• The flexures on the top of the solid legs allow for plate rotation

Mode 1 Mode 2 Mode 3 Mode 4 Mode 5 ModeFrequency (Hz) and Bandwidth

1 3.136±0.031

2 9.002±0.090

3 27.208±0.272

4 29.152±0.292

5 83.168±0.832

2.254cm

1.27cm

2 cm

0.8 cm

Amplitude and Frequency Determined from FFT output using averages and summations• Summation of amplitudes around the

peak gives the actual amplitude prediction

• Amplitude weighted average of frequencies around the peak in spectrum to find frequency prediction

Phase determined using Cross Correlation between data and predicted wave with no phase

SAVI takes a quarter of a second to collect data SAVI then takes a hundredth of a second to compute needed actuationSAVI then actuates for an eighth of a second

A new cycle is started every eighth of a second so that there is continuous actuation after SAVI’s initial cycle.

As a camera experiences rotation the image seen by a single pixel may change to another pixel while the shutter is open, causing a smeared image.

On the left shows a single pixel smear. A set of pixels (1, 2, 3) is rotated by 𝜃, the object seen by pixel2 is then also seen briefly by pixel1 while the shutter is open.

Flexures

Manufactured Purchased

Overview Design SolutionSAVI

• Tripod design with two actuators allows for a 2 DOF mitigation (tip & tilt)•Accelerometers placed on the

bottom plate and the top plate next to the solid leg for initial data collection

Test Stand• One actuating leg produces the EFT

vibration sensed by the SAVI system• Accelerometers placed on the top

plate are for testing purposes to determine residual vibration

Modal Analysis

Concept of Operations

Functional Block Diagram

Testing and Results

cDAQ D/A and A/D Converter

Charge Amplifier and Signal Conditioner

Signal Conditioner

SAVI, Test Stand, and Simulated Mass

Electronics Box with PDm200

Drivers

Wires to 24 V Power Supply

System Overview

Testing Setup• Location: MEMs Lab air table

• The vibrometer supplied by Polytecwas oriented such that the laser beam pointed vertically next to the desired accelerometer.

• MATLAB GUI was used to supply the voltage needed to produce the EFT

• SAVI system is started and stopped via the same GUI.

• Accelerometer and Vibrometer data is converted to displacements and displayed in real-time on the computer and is collected when desired.

• Residual accelerometer data closely matches rigid leg accelerometer data meaning the top plate is moving in POGO, with little tip and tilt.

• SAVI was capable of reducing pixel smear by at least 60% which satisfies the Tier 1 level of success.

• The SAVI system is 20cm x 20cm x 10cm and has a mass of 1.097 kg, satisfying part of the Tier 3 level of success.

Class Coordinator Advisor Industry AdvisersDale Lawrence Alexi Rakow David Ellis & Joe Hackel

Team Members

Wasseem Bel Blake Firner Joseph Schmitz Jackson VlayPatrick Byrne Corey Hyatt Justin Tomasetti Ben Zatz

Test Stand

SAVI

Mass

PolytecVibrometer

Laser Head

MEMS Anti-Vibration Air Table

Software

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