真空实验舱数字式压力控制系统设计与验证

摘要

针对脉冲等离子体推力器测试所需的容积大于60m3的大型真空实验舱对气压控制的要求,设计了数字式压力控制系统.该控制系统采用旋片泵组和罗茨泵构成两级串联的组合抽气方式对实验舱进行抽真空,具有较高的效率.基于双曲正切函数构建了变增益函数,从而实现对不同压力范围的变增益比例、积分和微分(PID)调节.试验结果表明,这一数字式压力控制系统能够实现精确、平稳的压力指令跟踪,压力控制精度为0.2%,优于0.5%的精度指标要求.%According to the requirement of the pressure control on a 60m3 large-scale vacuum experimental capsule for the test of pulsed plasma thruster, a digital pressure control system is designed. To get a higher efficiency, rotary-vane vacuum pumps and the Roots vacuum pump are used to constitute a series arrangement for vacuum exhaust. Based on hyperbolic tangent function, a variable gain function is designed in order to realize a variable gain PID regulator in different ranges of pressure. The test results show that the digital pressure control system can achieve accurate and stable command tracking of pressure, and the accuracy of the pressure control is 0.2％ which is better than the target requirements of 0. 5％.