Robust Position and Attitude Control of an Active Vibration Isolation System

Abstract

This paper considers robust control of an active vibration isolation system which is composed of a rigid platform and supporting air springs. The objective of control is to realize low compliance in the low frequency range for accurate position and attitude control, and to preserve high compliance in the high frequency range for good vibration isolation properties. The system is modeled by identification theory, and four subsystems describing strongly coupled dynamics are extracted from the six degrees of freedom of the motion. The weak coupling between subsystems as well as modeling errors in subsystems are treated as uncertainty of the system. A decentralized controller compatible with the subsystems is proposed, which achieves robust performance.