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Accession Number:
ADA243623
Title:
LQG Control of a Deformable Mirror Adaptive Optics System with Time- Delayed Measurements
Descriptive Note:
Master's thesis
Corporate Author:
AIR FORCE INST OF TECH WRIGHT-PATTERSONAFB OH
Report Date:
1991-12-13
Pagination or Media Count:
363.0
Abstract:
This thesis proposes a linear quadratic Gaussian LQG control law for a ground-based deformable mirror adaptive optics system. The incoming image wavefront is distorted, primarily in phase, due to the turbulent effects of the earths atmosphere. The adaptive optics system attempts to compensate for the distortion with a deformable mirror. A Hartman wavefront sensor measures the degree of distortion in the image wavefront. The measurements are input to a Kalman filter which estimates the system states. The state estimates are processed by a linear quadratic regulator which generates the appropriate control voltages to apply to the deformable mirror actuators. The dynamics model for the atmospheric phase distortion consists of 14 Zernike coefficient states each modeled as a first-order linear time-invariant shaping filter driven by zero-mean white Gaussian noise. The dynamics of the deformable mirror are also model as 14 Zernike coefficients with first-order deterministic dynamics. A significant reduction in total wavefront phase distortion is achieved in the presence of time-delayed measurements. Wavefront sensor sampling rate is the major factor limiting system performance. The Multimode Simulation for Optimal Filter Evaluation MSOFE software is the performance evaluation tool of choice for this research.
Distribution Statement:
APPROVED FOR PUBLIC RELEASE
