Robust controller synthesis for a large flexible space antenna

Abstract

This paper considers the problem of synthesizing a fine-pointing control system for a large flexible space antenna in the presence of modeling uncertainties. The plant to be controlled is a 122-meter diameter, space-based, "Hoop/Column" antenna. The mathematical model, based on a finite element analysis, consists of three rigid-body rotational modes, and the first 10 elastic modes. A preliminary robust compensator design for achieving the required pointing performance is obtained using linear-quadratic-Gaussian (LQG) and loop transfer recovery (LTR) methods for loop-shaping. The computations are performed using the LQG design package "ORACLS," and a recently developed singular value analysis package.