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S P A C E Structures, Propulsion, And Control Engineering C e n t e r. Control Team. Faculty Advisors Dr. Helen Boussalis Dr. Khosrow Rad Dr. Charles Liu. Student Assistants Jessica Alvarenga Alok Desai Harshit Tarsaria Kimberly Castro Heather Rudow Eric Diaz.
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S P A C E Structures, Propulsion, And Control Engineering C e n t e r Control Team Faculty Advisors Dr. Helen Boussalis Dr. KhosrowRad Dr. Charles Liu Student Assistants Jessica Alvarenga Alok Desai Harshit Tarsaria Kimberly Castro Heather Rudow Eric Diaz NASA Grant URC NCC NNX08BA44A
Outline • Background • Current Work • Repairs to PPA • OD GUI Results • Integration of PPA to DSP • Modeling of PPA to State-Space • Future Work • Timeline NASA Grant URC NCC NNX08BA44A
Background NASA Grant URC NCC NNX08BA44A
James Webb Space Telescope • Bigger Viewing Dish • 6.5m Mirror Panel • Gold-plated Beryllium Mirrors • Six times the collecting area • Deep Space • No atmospheric interference • Lag time due to distance • Segmented System • Control Algorithm • Decentralized System • Reconfigurable • Fault Detection and Isolation • Maintain Shape Control under Disturbance • IR Detection • Studies of Big Bang NASA/JPL-Caltech/R. Hurt (SSC) NASA Grant URC NCC NNX08BA44A
SPACE Telescope Testbed NASA Grant URC NCC NNX08BA44A 5
Control Requirements • Shape Control Hold nominal paraboloid shape • Pointing Control Accuracy of 2 arc seconds • Vibration Suppression 100:1 • Control Bandwidth 30HZ NASA Grant URC NCC NNX08BA44A
Current Work NASA Grant URC NCC NNX08BA44A
Current Work NASA Grant URC NCC NNX08BA44A
Repairs to PPA NASA Grant URC NCC NNX08BA44A
FINALLY!!! NASA Grant URC NCC NNX08BA44A
Tool Transportation NASA Grant URC NCC NNX08BA44A
Up Close NASA Grant URC NCC NNX08BA44A
Repairs to PPA NASA Grant URC NCC NNX08BA44A
Repairs to PPA • Laser replacement, alignment/focus, and PPA measurements NASA Grant URC NCC NNX08BA44A
Alignment of Mirrors Before After Fine Tuning NASA Grant URC NCC NNX08BA44A
PPA In Action PPA Lasers Primary Mirror NASA Grant URC NCC NNX08BA44A
Camera Views Camera 1 Camera 3 Camera 2 *Note: Pictures taken from approximate camera position NASA Grant URC NCC NNX08BA44A
OD GUI Results NASA Grant URC NCC NNX08BA44A
PPA Laser Path PPA (Pointing Verification) NASA Grant URC NCC NNX08BA44A
Optical Detectors Note: This image is before final alignment and without the shaping control NASA Grant URC NCC NNX08BA44A
Optical Detector GUI NASA Grant URC NCC NNX08BA44A
Integration of Pointing Control into Shaping Control NASA Grant URC NCC NNX08BA44A
Objective • H-infinity controller to handle both Shaping and Pointing (Currently just demonstrates shaping) • Integrate the Peripheral Pointing Architecture (PPA) Control with the Digital Signal Processor (DSP) • Some hardware/software changes will need to be made NASA Grant URC NCC NNX08BA44A
Current Configuration DSP Shape Control Shaping and pointing control are separate Testbed PPA Motion Controller Pointing Control Pointing Architecture NASA Grant URC NCC NNX08BA44A
Desired Configuration Shape and Pointing Control Shaping and pointing control are integrated Testbed DSP PPA Motion Controller Pointing Architecture NASA Grant URC NCC NNX08BA44A
ESP-301 Motion Controller • Currently Controls the PPA • Communication protocols include: • USB • Serial RS-232 • IEEE488 • GPIO • Currently controlled remotely using LabVIEW, separately from the DSP NASA Grant URC NCC NNX08BA44A
CMA 12PP Actuator • Linear Motion Actuator • Motorizes the PPA Platform • Stepper Motor • Controlled with the Newport Controller NASA Grant URC NCC NNX08BA44A
Digital Signal Processing (DSP) • We Want Direct Communication between the DSP and the Motion Driver/Controller NASA Grant URC NCC NNX08BA44A
Functional Block Diagram NASA Grant URC NCC NNX08BA44A
New Block Functions • DAQ – I/O between DSP and PC2 host/LabVIEW GUI • Need to determine/process output signals from DSP • Convert DSP signal to usable data for LabVIEW • PC2 host – LabVIEW GUI • Must re-establish control of ESP301 via USB • Upgrade GUI to receive data from actuators • ESP301 – sends commands to actuators • PPA Actuators – moves PPA NASA Grant URC NCC NNX08BA44A
State Space Modeling of PPA NASA Grant URC NCC NNX08BA44A
Background • We know the workings of a segmented telescope’s testbed and PPA components • We can now focus on model identification, implementation, and control design for the PPA • Two methods of SID: • Frequency Response • FEM Modeling and Modal Analysis NASA Grant URC NCC NNX08BA44A
Frequency Response NASA Grant URC NCC NNX08BA44A
Frequency Response • Frequency domain system identification is based on estimation of scalar transfer function • Main approach is by dividing the frequency domain data into different bands to get the resonant frequency NASA Grant URC NCC NNX08BA44A
Frequency Response • A chirp signal is applied to the Testbed with increasing frequency from 1 to 20 Hz NASA Grant URC NCC NNX08BA44A
FEM and Modal Analysis NASA Grant URC NCC NNX08BA44A
FEMAPExample NASA Grant URC NCC NNX08BA44A
FEMAP Result NASA Grant URC NCC NNX08BA44A
Future Work NASA Grant URC NCC NNX08BA44A
Timeline NASA Grant URC NCC NNX08BA44A
Timeline NASA Grant URC NCC NNX08BA44A
Questions? Thank You NASA Grant URC NCC NNX08BA44A