Study On Friction Characteristics And Compensation Of Hydraulic Cylinder In Electro-hydraulic Servo System

In the electro-hydraulic servo system,the existence of friction will have a serious effect on the dynamic and static characteristics of the actuator and other links.How to reduce the friction,improve the dynamic and static characteristics of the electro-hydraulic servo system is a hot spot in the current research field.This paper is aimed at the friction characteristics in the power mechanism of the electro-hydraulic servo system.The system model is established by using the Lu Gre friction theory.The system parameters are identified by using the least square curve fitting and genetic algorithm to identify the system parameters.The PID feedforward and adaptive backstepping method are used to compensate the friction force of the system.The correctness of the compensation method is verified by experiments.The specific research contents are as follows:(1)Using Lu Gre friction theory of electric hydraulic servo system modeling,using Matlab/Simulink software simulation,friction characteristics analysis;using the experimentally measured data,the theory of least squares method and genetic algorithm,the implementation model of the dynamic and static parameter identification;establishment of electro-hydraulic servo system and its friction model.(2)According to the characteristics and the influence of friction in the system,the precise system model based on the study of friction compensation control method,design compensation controller and adaptive backstepping control strategy of feedforward compensation PID,adjusting the compensation effect obtained by structure and parameter design of the controller,in order to improve the dynamic and static performance of electro-hydraulic servo system control precision.The correctness of the compensation method and the simulation results of the proposed.(3)Experimental research: according to the measured data,the accurate mathematical model and the friction characteristic model of electro-hydraulic servo system are established by system identification method,and the correctness of the established mathematical model and the feasibility of the friction compensation control method are verified by experiments.