Disturbance suppression of pneumatic anti-vibration apparatuses using automatic frequency estimation PIS control

Abstract

In this paper, we designed a PIS control method that can automatically estimate the disturbance frequency using Schmitt trigger and implemented it in a pneumatic vibration isolator. A pneumatic vibration isolator is used for vibration suppression of the semiconductor exposure apparatus. The pneumatic vibration damping device adopts a structure in which the isolated table is supported by an air spring and compressed air supplied and exhausted from the compressor is supplied to the air spring. As this compressed air is accompanied by pressure fluctuations, it causes vibrations in the isolated table. PIS control using S compensator which suppresses periodic vibration in PI control is used to suppress this flow disturbance. However, in the PIS control, when the frequency of the actual disturbance fluctuates, the vibration suppression effect by the PIS control deteriorates. Therefore, we proposed a PIS controller that can automatically estimate the frequency of disturbance using Schmitt trigger. By implementing this method, we succeeded in improving the vibration suppression effect by comparing displacement of the base of conventional PIS control method and automatic frequency estimation PIS control.

Keywords

• vibration isolation
• vibration control
• pneumatic equipment
• internal model principle