Accession Number : ADA289309

Title :   Control of a Large Space Structure Using Multiple Model Adaptive Estimation and Control Techniques.

Descriptive Note : Master's thesis,

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING

Personal Author(s) : Griffin, Gordon C., Jr

PDF Url : ADA289309

Report Date : DEC 1994

Pagination or Media Count : 249

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.

Descriptors :   *SYSTEMS ENGINEERING, *SPACECRAFT, *ADAPTIVE CONTROL SYSTEMS, MATHEMATICAL MODELS, ALGORITHMS, COMPUTERIZED SIMULATION, LINEAR SYSTEMS, LINE OF SIGHT, VIBRATION, COMPUTATIONS, FLIGHT CONTROL SYSTEMS, TOOLS, PARAMETERS, GAUSSIAN NOISE, KALMAN FILTERING, BENDING, ESTIMATES, COSTS, RESONANT FREQUENCY, PLATFORMS, PRECISION, QUADRATIC EQUATIONS, FLEXIBLE STRUCTURES, TRIPODS.

Subject Categories : Operations Research
      Unmanned Spacecraft

Distribution Statement : APPROVED FOR PUBLIC RELEASE