Characteristics analysis and control study of a pneumatic proportional valve

To improve the vehicle pneumatic brake system, the feasibility of using pneumatic proportional valve as pressure regulator is studied in this article. Take proportional relay valve of WABCO as the research object. First, the mathematic model for proportional relay valve is established in Matlab/Simulink and verified through open loop experiment. Then, the effects of main physical and geometrical parameters on characteristics of the valve are analyzed. Finally a PI controller with feedforward and anti-windup compensation is designed. Study shows that the valve has a good performance of high linearity and would not be affected by supply pressure. The designed controller improves the pressure regulation precision and robustness.