Control of a New Type of Direct Drive Piezoelectric Servo Valve

A new type of two-stage direct drive piezoelectric servo valve is designed and the control system of it is presented in this paper. The multilayer piezoelectric actuator is used as the electricity-machine converter in this new servo valve, which makes the electrohydraulic servo system has higher precision and extensive applied field. The bidirection piecewise gearshift integral PID control method proposed in this paper can solve the nonlinear problem of the servo valve and satisfy the demand of the control system well. Experiment results have confirmed the effectiveness of the proposed method.