Effects of Air Flow Disturbance of Spool Valve on Vibration Control of Active Pneumatic Vibration Isolation System

Active pneumatic vibration isolation system (APVIS) is widely used in IC equipments and high precision metrology devices. Proportional spool valves are normally used as its actuator. However, it exhibits strong non-Linearity, such as dead zone and stick-sLip effect, which results in flux fluctuation, to greatly degrade the vibration isolation performance. In this paper, a dynamic model for air spring of APVIS is presented, and the active control model of APVIS is built which uses PI algorithm to control spool valve and sky-hook damper to depress the resonance. The simulation results show that vibration caused by pneumatic flux disturbance is ampLified near the resonance frequency of APVIS and pneumatic flux disturbance has great influence on vibration isolation performance between the bandwidth of 0.2~1.0Hz.