Abstract:Aimed at the problems such as low efficiency, unstable speed regulation and slow response speed when traditional motor was used as the power unit of valveless hydraulic system, a vector controlling permanent magnet synchronous motor(PMSM) was proposed to replace the traditional motor to drive the pump in the valveless hydraulic system, and a mathematical model of valveless hydraulic system was established. Traditional PID was difficult to solve the problems of time-varying and non-linear in the control process of the valveless hydraulic system, so the fuzzy PID position controller based on the valveless hydraulic system was designed. AMESim and MATLAB were used for joint simulation of valveless system, and the simulation results were compared with those of traditional PID.The results show that the fuzzy PID control method has good effect on response speed, anti-interference and position tracking accuracy of the valveless hydraulic system driven by PMSM.