变泄漏容腔内气体的高精度恒压控制

High-precision constant pressure control of gas invariable leakage chamber

在精密测试与控制场合,常需要稳定压力的供气。然而,采用压力调节阀精度低、响应慢,无法满足高精度供气需求,且难以应对泄漏工况。采用高频响的比例阀,为小体积容腔设计了一个基于模糊比例-积分的高精度恒压控制系统。为验证系统在泄漏工况下的有效性,容腔还连接了一个额外的比例阀,从而开展密闭、恒泄漏、变泄漏三种情况下的系列试验研究。结果表明,所设计的恒压控制系统可适应多种恶劣工况。在大幅变泄漏工况下,10 L、20 L和30 L容腔压力控制的最大稳态误差分别约为610 Pa、550 Pa和490 Pa,所实现的压力控制精度已接近压力传感器自身精度,远大于传统精密减压阀所调控的精度,且响应更快。此外,试验结果也表明所设计的控制器对10~30 L的容腔有较好的适应性。

In precise testing and control occasions,a stable air pressure supply is often required.However,the use of pressure regulating valves has low accuracy and slow response,which cannot meet the requirements of high-precision air supply and is difficult to deal with leakage situations.A high-precision constant pressure control system based on Fuzzy PI was designed for small volume chambers by using a proportional valve with high frequency response.In order to verify the effectiveness of the system under leakage conditions,an additional proportional valve was connected to the chamber to carry out a series of experimental studies under three conditions of confinement,constant leakage,and variable leakage.The results showed that the designed constant pressure control system can adapt to a variety of harsh operating conditions.The maximum steady-state errors of the pressure control for the 10 L,20 L and 30 L chambers were around 610 Pa,550 Pa and 490 Pa under the condition of greatly varying leakage,respectively.The pressure control precision achieved was close to the precision of the pressure sensor itself,much higher than the precision regulated by the traditional precision pressure reducing valve,and much faster in response.In addition,the test results also showed that the designed controller has good adaptability to the chambers with a volume range of 10 L to 30 L.