Controlling a large flexible structure to mimic a rigid one.

Abstract

Analytical and experimental comparisons are presented for two control laws used in a laboratory structure designed to simulate large space structures. The proposed control laws are based on minimizing the amount of energy imparted to the flexible modes during the maneuver. Structure modeling and various control techniques are discussed. In the proposed modeling procedure, the finite element method is used to describe the equations of motion for a given structure. The main objective of the analysis is to determine optimal actuator locations and the command forces to the actuators such that the structure will follow a desired trajectory while minimizing the internal energy to the flexible modes. The numerical simulations are verified experimentally using a digital implementation of the control laws. Critical issues related to experimental implementation are discussed. A closed-loop control system design which will take care of nonlinearities and uncertain inputs is included in this dissertation.