Research On Asymmetric Valve Control Electro-Hydraulic Position Servo Control System

Electro-hydraulic position servo control systems are widely used in missile systems,numerical control machine tools,aerospace,military weapons and other fields because of their high power density ratio,high precision,high frequency response and many other advantages.Because it belongs to a typical nonlinear system,there are parameter perturbations,large disturbances,and it is difficult to obtain accurate mathematical models,which affects the dynamic response speed,control accuracy and anti-interference performance of the electro-hydraulic position servo system.Based on this,this paper studies the control strategy and experimental verification of the valve-controlled asymmetric cylinder electro-hydraulic position servo system under the condition of parameter perturbation and random disturbance.First of all,for the electro-hydraulic position servo system with strong non-linearity,parameter perturbation and other factors,as well as the slow response speed and poor tracking performance of the system due to the relatively low damping of the system,this paper adopts fuzzy adaptive control with positive speed feedback and negative acceleration.Compound control strategy combined with feedback.The open loop gain and damping ratio of the system are improved through positive speed feedback and negative acceleration feedback,thereby improving the dynamic response of the system and reducing the position error.At the same time,feed forward control is used to broaden the system bandwidth and further reduce the position tracking error.The simulation analysis shows that the dynamic response speed of the system using the compound control algorithm is 76.9% higher than that of the fuzzy PI,and nearly 84.2% higher than the traditional PI control.In addition,traditional PI control and fuzzy PI control have certain oscillations during the ascent process,while the curve of the compound control algorithm is smoother.The compound control algorithm makes the system dynamic response faster,reduces the system tracking error,and reduces the system oscillation,With strong robustness.Secondly,for the electro-hydraulic position servo system,it is difficult to establish an accurate mathematical model,parameter perturbation,and large unknown disturbance.An improved active disturbance rejection control strategy is adopted to reduce the traditional active disturbance rejection controller from the third order to the first order.Obtain the signal and use the position error as the controller input,which reduces the phase lag caused by the expanded state observer,thereby improving the system response speed.By observing and compensating the position error of the system,the high-order terms and unknown disturbances of the system are regarded as total disturbances to simplify the controller structure.Theoretical and simulation analysis results show that the first-order nonlinear active disturbance rejection controller designed in this paper can achieve rapid response and high-precision control of the system,has good suppression ability against unknown disturbances and other factors,and has good control quality and robustness.Sex.Finally,in order to verify the feasibility of the above control system,the system hardware circuit and the host computer visualization platform are designed,and the electro-hydraulic position servo system experimental platform is built.The experimental results show that: Compared with PID control,the improved auto disturbance rejection control response speed increases About 55.56%,the anti-disturbance ability is greatly improved.Compared with the traditional active disturbance rejection control,the response speed is increased by about 44.44%.In addition,the improved active disturbance rejection control introduces a given signal differential,which suppresses the overshoot of the system.The controller and control strategy designed in this paper can achieve high-precision position tracking and fast dynamic response.