Simulation Analysis of Fluid Force Compensation Control Strategy for High Pressure Valve Port
Direct proportional servo valve is a new type of single-stage servo valve,which uses proportional solenoid or linear force motor to drive the spool valve directly.Because it has the advantages of low cost,high frequency response and strong anti-pollution ability,it is widely used in high-speed and high-precision hydraulic control systems,such as feed control of injection molding machine and plate thickness control system of rolling mill.Traditional direct proportional servo valve adopts PID control strategy to achieve precise spool position control.However,under the condition of high pressure(20 MPa)and large flow(100 L/min),the flow force disturbance of the valve spool becomes more and more serious,which leads to slow response speed,spool dither and it cannot meet the high-precision control requirements of the proportional servo valve.In order to solve the problem of worsening flow force disturbance,a sliding mode controller based on exponential convergent disturbance observer is proposed in this paper.The sliding mode controller is designed by establishing spool dynamic model to ensure high dynamic tracking performance of the spool position.The disturbance observer based on exponential convergence is used to estimate the uncertain disturbance of flow force in the spool dynamic model and to compensate spool flow force disturbance under high pressure and large flow conditions.A co-simulation model of direct proportional servo valve system is built for simulation verification.The simulation results show that the proposed controller can solve the interference problem of spool flow force disturbance on spool position control under high pressure and large flow conditions.
direct proportional servo valvespool position controlsliding mode controlflow force
万方数据
维普
