Abstract:In the electro-hydraulic proportional servo valve, the hydraulic force has strong nonlinearity, and the linearity between the driving current and the spool displacement under the open-loop control is poor. It is difficult to achieve good control effect by using the traditional PID control algorithm. In view of this phenomenon, a position negative feedback control method is proposed, which is based on the analysis of the hydrodynamic characteristics of the valve core. By building the controller model and the spool force model of proportional servo valve, the experimental verification is carried out. The results show that this method can effectively solve the nonlinear problem of current spool displacement in control, and the control stability is obviously improved.