Research On Friction Characteristics And Variable Structure Control Of Continuous Rotating Electro-hydraulic Servo Motor

As an important driving device for the flight simulation semi-physical simulation turntable,the continuous rotary electro-hydraulic servo motor has good performance such as high frequency response,high precision,and ultra-low speed.The control performance of the continuous rotary electro-hydraulic servo motor system is affected by uncertain nonlinear factors such as friction torque interference during the operation of the motor system.Therefore,this article focuses on the influence of friction torque on system performance,and the variable structure control strategy is combined to further improve the performance of the motor system.Referring to the relevant literature at home and abroad,the current research status of continuous rotary motors and electro-hydraulic servo systems are briefly described,the types of friction models and commonly used friction compensation methods are summarized,and the characteristics and current research status of sliding mode variable structure and flexible variable structure controllers are analyzed.On this basis,the research focus of this paper is put forward.First of all,the relevant parameters of the continuous rotary motor system are considered,the state space model of the continuous rotary motor system is established by using traditional mathematical modeling;A continuously differentiable dynamic friction model is adopted,the data is collected through experiments,the genetic algorithm is used for parameter identification to obtain an accurate friction model,and a friction torque compensation scheme for continuous rotary motor system based on continuous friction model is determined.Secondly,the uncertain nonlinear factors affecting the electro-hydraulic servo system of the continuous rotary motor are considered,a sliding mode variable structure controller for the continuous swing motor system based on the improved power reaching law is proposed,and an improved power reaching law is designed,it can adaptively adjust the chattering;The switching function is designed,the control rate is derived;Combined with friction compensation,and the empirical method is used for parameter tuning.Compared with the PID control,the effectiveness of the continuous rotary motor electro-hydraulic servo system based on the improved power reaching law sliding mode variable structure controller is verified.Then,the dynamic flexible variable structure control theory is used for reference to improve the chattering problem of the sliding mode control system,which is simplified and merged with the PD controller,a simplified dynamic flexible variable structure PD controller was proposed,combined with friction compensation,and the genetic algorithm is used for parameter tuning online;Compared with the sliding mode variable structure controller,the simplified dynamic flexible variable structure PD controller is verified to improve the performance of the electro-hydraulic servo system of the continuous rotary motor.Finally,based on the simplified dynamic flexible variable structure PD controller,an experimental study of the continuous-rotating electro-hydraulic servo motor system is carried out.Compared with the simulation results,the feasibility of the controller is verified.