Study On Trajectory Tracking Control Of Optical Mirror Polishing Robot Based On Active Disturbance Rejection

With the increasing application of optical systems,the demand for optical components is gradually increasing.The requirements for the aperture,relative aperture,processing accuracy,lightweight degree,processing efficiency and production cost of optical parts are also gradually increasing.The optical manufacturing industry must seek high-efficiency,high-precision processing equipment and processing control system.This topic takes the optical mirror polishing robot as the research object.The optical mirror polishing robot receives complex forces during the grinding process.The rotation and revolution of the grinding disc have a greater impact on the mechanism,and the gravity and movement of the mechanism also affect the accuracy of the mechanism.In addition,the parallel mechanism is a nonlinear system with more variables,more parameters,and strong coupling.Therefore,the motion characteristics,servo control system and trajectory tracking control of the parallel mechanism are analyzed and studied.The main content can be summarized as follows:(1)First,according to the structural characteristics and mechanism parameters of the optical mirror polishing robot,the parallel part of the mechanism is analyzed through spatial pose description and coordinate transformation,and the inverse kinematics equation is obtained,Then,the velocity and acceleration motion curves of each part are obtained.The three-dimensional coordinate search method is used to determine the working boundary of optical polishing,and certain indicators are used to evaluate the kinematic operation performance of the studied object.On this basis,the method of virtual work principle is adopted to analyze the force of each component,so as to solve the dynamic model of the parallel control part,which is convenient for the study of the trajectory tracking control algorithm in the subsequent chapters.(2)In view of the influence of a series of uncertain factors such as external environment disturbance,internal load change,parameter perturbation and coupling in the control process of optical mirror polishing robot,the active disturbance rejection control(ADRC)method is adopted to effectively improve the interference suppression ability and robust performance of polishing robot control system.Based on the servo control system of permanent magnet synchronous motor with each driving branch,the traditional ADRC algorithm is improved.The tracking differentiator,extended state observer and error feedback control law are designed in the ADRC,and the ADRC servo control system of driving branch is established.(3)The ESO based sliding mode control method is used for trajectory tracking control,the nonsingular terminal sliding surface is designed,and the extended state observer is designed to compensate the disturbance error in the operation process.At the same time,the sufficiently small estimation error and the stabilization of the closedloop system are achieved in finite time.It not only realizes high precision trajectory tracking control,but also ensures the rapid response performance of the system.(4)According to the optical mirror test standard,build the optical mirror polishing robot experimental platform.According to the research results,the overall framework of the robot control system is designed,including the selection of upper computer,control card,driver and other hardware,and the hardware platform of the control system is built;in order to realize the grinding and polishing movement of the robot efficiently and quickly,the software platform is built to control the machining of the robot,and the trajectory tracking data in the grinding process of the robot is collected by using relevant sensors According to the simulation results,the control effect of the designed model is verified.