Model verification for active control of microvibrations

Abstract

Microvibrations, generally defined as low amplitude vibrations at frequencies up to 1 kHz, are now of critical importance in a number of areas. One such area is on-board spacecraft carrying sensitive payloads, such as accurately targeted optical instruments or micro-gravity experiments, where the microvibrations are caused by the operation of other equipment, such as reaction wheels, necessary for its correct functioning. It is now well known that the suppression of such microvibrations to acceptable levels requires the use of active control techniques which, in turn, require sufficiently accurate and tractable models of the underlying dynamics on which to base controller design and initial performance evaluation. Previous work has developed a systematic procedure for obtaining a finite-dimensional state space model approximation of the underlying dynamics from the defining equations of motion which has then been shown to be a suitable basis for robust controller design. This modeling approach is based on the use of Lagrange's equations of motion and is one of a number of possible models possible in this area. In this paper, we describe the experimental validation of this model prior to experimental studies to determine the effectiveness of the designed controllers with the objective of establishing the effectiveness of this procedure both stand alone and against alternatives.