The Study on Gas Pressure Control Method with Micro-machined Silicon Micro-valve

摘要

A pneumatic pressure control method using two Micro-machined Silicon Micro-valves is proposed, and experimentally evaluated. An electro-statically actuated silicon micro-valve, which modulates a gas flow, converts an electric signal to a pneumatic signal for pressure or gas flow control. Instead of the former multi-channel and multi-diameter, multi-source scheme, this method simplifies the structure of gas path, solve the low pressure and flow control and realize continuous adjustment of pneumatic pressure control. A analogy silicon pressure sensor and a digital-quartz pressure sensor are introduced, the analogy sensor has a high speed response to ensures the control performance, and a digital sensor has a good accuracy up to 0.01%, it act as the system’s standard sensor to guarantees its lower uncertainty. A two-loop-closed feedback PID control method is designed. The inner loop is realized by analogy electric circuit design. A novel method of automatic track and calibrating is developed through the computer and the microcomputer communicating system via RS232. Its output range of pressure is 0 ～ 120kPa absolute. Its uncertainty is 0.01% FS per year.