Research On Intelligent Control Strategy Of Valve Controlled Cylinder Electro-Hydraulic Position Servo System

Valve-controlled cylinder electro-hydraulic position servo system has been widely used in all walks of life for its advantages of large power to weight ratio and fast response speed.With the development of national defense industry technology,the demand for high performance electro-hydraulic servo system is becoming more and more urgent.But its inherent nonlinear characteristics limit the improvement of its control performance.Therefore,aiming at the nonlinear problem of electro-hydraulic servo system,it is of great significance to study a more effective control method.Aiming at the difficulty of precise modeling of electro-hydraulic servo system with strong nonlinear characteristics,a method combining mechanism modeling and parameter estimation was proposed.Firstly,the mathematical model of the system is deduced theoretically.Then,the closed-loop position transfer function of discrete domain is obtained by the least square method,and the unknown physical parameters in the continuous domain transfer function model are solved by the bilinear transformation principle to further improve the accuracy of the model.In view of the low efficiency of PID control parameter setting of electro-hydraulic servo system,which affects its dynamic performance improvement,A PID control parameter optimization method based on differential evolution algorithm is proposed.Compared with the traditional PID controller,the simulation results show that the PID optimization control method effectively reduces the system overshoot and improves the response speed,but has limited inhibitory effect on external interference.In order to solve the problem of parameter time-varying and nonlinear interference suppression,a robust sliding mode optimization control method was proposed.The state observer was established to estimate the internal state of the system,saturation function was introduced to suppress chattering of the system,and differential evolution algorithm was used to optimize the control parameters to achieve the optimal control.Simulation results show that the proposed control method has better control performance and enhances the robustness of the control system.The experimental platform of electro-hydraulic servo system was built,and the experimental program based on Power PMAC controller and Matlab/Simulink was designed.Experimental results show that the proposed parameter estimation method can accurately describe the actual system,and the controller has strong robustness,which effectively improves the position tracking accuracy of the system.