Active Vibration Damping of the Space Shuttle Remote Manipulator System

Abstract

Controls-structures interaction is a technology currently under development for application to large flexible space vehicles. The goal of this technology is the improvement of spacecraft performance through active control of the structural dynamic response of the vehicle. This goal is particularly important for modern spacecraft designs where large size and reduced stiffness make structural response a significant contributor to vehicle dynamics. Analysis and design methods have been developed to analyze and predict flexible spacecraft performance, but the technology remains largely unvalidated by hardware experiments, demonstrations, or applications, particularly in-space flight applications. One potential application considered is to provide active damping augmentation of the Space Shuttle remote manipulator system. The objective of actively damping the manipulator is to demonstrate improved structural dynamic response following payload maneuvers and Shuttle reaction control system thruster firings. This paper describes an initial analysis effort to determine the feasibility of controlling the flexible dynamic response of the arm. The approach to the study is summarized and results from both linear and nonlinear performance analyses of candidate control laws are presented. Results indicate that significant improvement in dynamic response can be achieved through active control if measured arm tip acceleration was made available for feedback.