Abstract
Active control type pneumatic isolation systems are widely used in semiconductor production processes. Most of them are actively controlled by nozzle flapper type servo valves, since they have fine characteristics as imperfect pressure integrators. But nozzle flapper type servo valves exhaust a lot of compressed air, for the sake of controllability. In this research, we firstly develop a pressure differentiator using an isothermal chamber, a cylindrical type laminar flow element and a differential pressure sensor. Then, by using the developed pressure differentiator and a spool type servo valve, an imperfect pressure integration system with much lower exhausted air flow rate compared to the system with nozzle flapper type servo valve, is constituted. Finally, the proposed pressure integration system is applied to the control of active vibration isolation system. The experimental results indicate superior performance of the developed system, especially in much lower energy consumption.
