The Performance Research Of Electro-hydraulic Position Servo System Based On PWM On-off Valve

Electro-hydraulic servo system integrating machine, electricity and liquid, as with good stability, high control precision, big output power and other characteristics, it has been widely used in various industrial fields. For saving the cost of electro-hydraulic servo system, and improve the control performance of system. In this paper, the on-off valve is applied to electro hydraulic position control servo system based on PWM, and the performance characteristics under load conditions are studied.The mathematical models of on-off valve and hydraulic cylinder are established, system transfer function is derived, lay the foundation for later closed-loop system stability analysis and control strategy research. Secondly, the simulation model of system is established by AMESim, and the static performance of system is researched, pressure and flow characteristics are studied under different load condition, the performance of the whole system affect by Key element parameters are analyzed. Thirdly, the stability of closed-loop system is analyzed by the mathematical model, according to the characteristics of the mathematical model, proportional control algorithm is selected, and control parameters are calculated. Then the control characteristics simulation of closed-loop system based on mathematical models and AMESim model have been studied. The dynamic response characteristics were studied for the closed-loop control system by using AMESim.Thus the system has good dynamic response to the input signal. Finally, the experiment system of on-off valve controlled electro-hydraulic position servo based on PWM has been built, the control programs are developed by using LabVIEW, and finish the experimental system research, at last the experimental data and simulation results are compared and verified.Through theoretical analysis and experimental research, system has good dynamic response. System has fast response speed, high control precision, besides, system motion characteristics is not affected by the load change. The results show that, experimental system has good performance, compared to theoretical research, experimental data verify the correctness of the theory, and it will provide referential basis for the depth study on electro-hydraulic position servo system.