Multivariable Methods for the Design, Identification, and Control of Large Space Structures. Volume 3. A Study of the Integrated Control/Structure Design Optimization Problem for Large Flexible Structures.

摘要

A comparison of optimal and suboptimal estimation applied to large flexible structures under perfect and imperfect model information conditions is presented. The filters estimate the modal positions and velocities of a simple pinned-pinned beam. Among the types of estimators investigated are full and reduced-order centralized estimators, reduced-order decentralized estimators, and one-mode and two-mode sensitivity-shaped estimators. The suboptimal estimators are shown to have lower position rms error values than the optimal estimator when 20% errors in the structural frequencies are present. The sensitivity-shaped estimators produce more accurate position estimates when velocity sensors are used than any of the reduced-order Linear Quadratic centralized or decentralized estimators. A method for choosing the gains of the sensitivity-shaped estimators given. Robustness of the system is discussed using a proposed phase-shaping method and the Lyapunov method. The closed-loop system with the one-mode sensitivity-shaped filter is proven to be marginally stable with the former method and asymptotically stable with the latter method, provided controller gains satisfy certain outlined requirements. (Author) (kr)