On an Improvement of Hybrid Vibration Isolation System. Application of Frequency Shaped Weighting Function and Phase Compensation.

Abstract

This paper proposes a hybrid-type vibration isolation system controlled by a frequency shaped weighting function and a phase compensated LQ control method. The hybrid system is composed of a passive spring-damper system reducing vibrations of high frequency area and an active one reducing those of low frequency area. This system is controlled by the phase compensated digital LQ optimization method with a frequency shaped weighting function. By the proposed method, the phase lag of the control system is compensated so that the vibration isolation performance is improved. Simulations for the active system are carried out and the effectiveness of the phase compensation is shown. Then, experiments for the hybrid system are carried out for sinusoidal or random excitations. It is confirmed that the purposed hybrid system has the excellent isolation performance for excited vibrations over the wide frequency area.