基于双阀调节的稳压腔开环-闭环复合控制方法

In order to ensure the overall performance of large-scale air pipeline test facility，the pressure stabilizing chamber with double-valve is required to achieve accurate pressure control. Therefore，an open loop-closed loop compound control method for pressure stabilizing chamber based on double-valve control is proposed. Firstly，a virtual controller is constructed，which includes the open-loop control of the butterfly valve and the closed-loop control of the sleeve valve. The virtual controller and the pressure stabilizing chamber are combined through the total discharge flow to establish an open loop-closed loop compound control structure. Secondly，the controller is designed according to the control structure，and a tracking differentiator is introduced into the open loop controller to solve the pressure change rate and plan the transition process of the command pressure. Based on this，the discharge flow of the butterfly valve is calculated according to the chamber pressure differential equation，and hydraulic cylinder displacement command is obtained by considering the dynamics of the butterfly valve. The closed-loop control loop is constructed based on the linear model of the pressure stabilizing chamber and the sleeve valve model. And the closed-loop PI controller is designed. Finally，the simulation verifications of servo tracking performance and anti-interference performance are carried out. The overshoot of the pressure step response is 0.89%，the steady state error is less than 0.03%. The pressure fluctuation of the chamber is less than 0.5% when the external interference flow varies widely，and the pressure deviation is less than 0.75kPa. The simulation results show that the method proposed in this paper can effectively coordinate the actions of the butterfly valve and the sleeve valve，and realize the precise control of the pressure of the chamber.