Research On Electro-hydraulic Servo Position Tracking Control Strategy

Electrohydraulic servo systems are widely used in manufacturing and aerospace fields due to their advantages in both hydraulic and electrical aspects.In the field of electrohydraulic servo control technology,electro-hydraulic servo position tracking control plays an important role,and good control performance can significantly improve production efficiency.During the exploration process,it was found that there are many factors that limit the performance of the electro-hydraulic servo system.Therefore,studying how to improve the control performance of the electro-hydraulic servo system has important practical significance.The main research work of this article is as follows:Firstly,in order to study the control performance of actual electro-hydraulic servo systems,a position tracking control platform for electro-hydraulic servo systems is designed and constructed.The electro-hydraulic servo position tracking control platform consists of a hydraulic pump station,a dual cylinder loading experimental mechanism,and a computer control system,which can achieve symmetrical and asymmetric hydraulic cylinder displacement tracking experiments.A computer control system mainly composed of an industrial computer and a control cabinet is used to collect displacement signals and output control quantities through a data board card.On the basis of analyzing the mechanism of the electro-hydraulic servo position tracking control system,the mathematical model of the system is obtained by modeling various parts of the system.Then,in response to the problems of uncertain parameters and unknown disturbances in the electro-hydraulic servo system,and the inability of traditional PID control methods to achieve ideal tracking accuracy,a reference model disturbance observer based electrohydraulic servo position tracking control method is proposed.Firstly,design a controller to accurately track the output of the ideal reference model system to the positioning shift signal.Secondly,the part of the actual system that differs from the ideal reference model is considered as the total disturbance,and a disturbance observer is designed to observe it.Finally,a control law is designed to compensate for the total disturbance,so that the output of the actual system can accurately track the positioning shift signal.The simulation and experimental results show that the disturbance observer based on the reference model can effectively improve the system control accuracy and reduce the system dynamic control error compared to PID control in the electro-hydraulic servo position tracking control method.Finally,to address the issue of friction nonlinearity affecting the performance of lowspeed electro-hydraulic servo position tracking control,a friction compensated electrohydraulic servo position tracking auto-disturbance rejection control method is proposed.Firstly,a Lu Gre friction model of the electro-hydraulic servo system is established and parameter identification is carried out.Based on this model,a controller combining friction compensation and auto-disturbance rejection control is designed.Secondly,a third-order linear extended state observer is designed to observe the total disturbance.Finally,consider designing a linear state error feedback control law with friction compensation as the control input for the actual system.The simulation and experimental results show that using this method can improve the system control accuracy and achieve fast and accurate tracking of given inputs.