Multi-degree-of-freedom hybrid control system for high technology facilities

A multi-degree-of-freedom hybrid control system using air springs and magnetostrictive actuators is developed in order to protect high technology facilities against microvibration. Air Springs could isolate the platform from the floor subject to high frequency ground motion because of its low-pass filter, and could also support the platform. And active vibration isolation system generally has characteristics of high-pass filter, thereby abating low frequency disturbance effectively. In order to examine the performance of the hybrid control system, the analytical models of a coupled hybrid system and magnetostrictive actuators are established. This system is designed to protect the platform against microvibration of the multi-degree-of-freedom (MDOF) by giving feedback of the absolute displacement and absolute velocity of the platform. A hybrid control system controller is established in accordance with linear quadratic Gaussian (LQG) control theory. The simulation results from MATLAB show that the proposed MDOF hybrid control system for microvibration is feasible and effective if the controller is properly designed, regardless of the direct disturbance, ground disturbance, or both together.