Date of Award

12-1994

Document Type

Thesis

Degree Name

Master of Science in Electrical Engineering

Department

Department of Electrical and Computer Engineering

First Advisor

Peter Maybeck, PhD

Abstract

A moving bank multiple model adaptive estimator-controller (MMAE-MMAC), based on linear system, quadratic cost, and Gaussian noise (LQG) assumptions, is used to quell unwanted vibrations in a large flexible space structure. The structure, known as the SPace Integrated Controls Experiment, or SPICE, exists at Phillips Laboratory, Kirtland AFB, NM. The structure consists of a large platform and a smaller platform connected by a tripod of flexible legs. The purpose of the control system is to maintain a very precise line-of- sight vector through the center of the spacecraft. Kalman filtering, used to estimate the position and velocity of the bending modes of the structure, and LQG control techniques are the primary design tools used in the MMAE-MMAC algorithms. Implementing a parallel bank of filters increases robustness when uncertainties exist in the system model, here specifically allowing adaptation to uncertain and changing undamped natural frequencies of the bending modes of the structure. A moving bank is used to reduce computational loading. The MMAE-MMAC design method provides an excellent method of estimating undamped natural frequency variations and quelling vibrations in the structure. The MMAE-MMAC was able to track numerous parameter changes and jumps while providing adequate control for the structure.

AFIT Designator

AFIT-GE-ENG-94D-14

DTIC Accession Number

ADA289309

Comments

The author's Vita page is omitted.

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