Performance limitations and vibration control for isolation systems

Abstract

Over the past few decades, various passive and active vibration isolators have been developed to enhance isolation performance for mechanical systems and equipment. However, a fundamental question remains: what is the maximum achievable performance of an isolation system using these isolators? This paper investigates the inherent performance limitations of isolation systems and proposes strategies for vibration control within these constraints. In the first part, we employ the Youla parametrization to derive analytical expressions for the performance limitations of the frequency response functions (FRFs) of the isolation system, including the maximum value and invariant points of single FRF, as well as inherent trade-offs among different FRFs. In the second part, these theoretical limitations are applied to vibration control. Based on the derived performance limitations, we propose the procedures for achieving FRF assignment in the isolation system. Additionally, a simple controller is proposed for the isolation system, enabling effective vibration attenuation over almost the entire frequency range with only three adjustable parameters. Numerical examples demonstrate that the isolation system with the proposed controllers has good time-domain and frequency-domain performance.