Research On Calibration Technology Of Robot Dynamic Tracking System

According to the literature research,95% of the positioning error of the robot is caused by the inaccuracy of the kinematics model.At present,most of the calibration models of robots are based on DH model with 4-DOF parameters,but its defect is the singularity and mutation of kinematic parameters.In view of this,this paper first establishes a 5-DOF MDH model,and uses robotics toolbox to verify the correctness of the established kinematics model by combining numerical and graphics.Based on the project requirement of a university teaching platform,the whole control scheme based on machine vision is built firstly,including machine vision system,motion control system,conveyor line system and the surrounding supporting facilities;then the electrical selection and programming code of each part are specified;among them,machine vision system also needs to complete the conversion of pixel coordinates to world coordinates.As well as machine vision and hand-eye calibration of manipulator,the numerical relationship between machine vision and manipulator is established to provide data guarantee for dynamic tracking of robot.Secondly,this paper carries out kinematics analysis of four-axis industrial robots in series,uses the modified DH method to get the positive kinematics solution of the robot,and uses the numerical method to get the inverse kinematics solution,and uses the Robotics toolbox to verify the correctness of the kinematics equation by combining numerical and graphics;at the same time,it also makes theoretical preparation for error source analysis and calibration content.Thirdly,combining kinematics and differential transformation,this paper establishes a mathematical model of single link error and geometric parameters as well as motion variables.Then,through the product operation of link matrix,the error model of the position and posture of the end wrist relative to the basic coordinate system of the Four-Degree-of-Freedom robot is solved.Finally,through the simulation analysis of MATLAB,the geometric parameters of the end wrist position and posture relative to each link and each other are obtained.The numerical relationship of joint motion variables.Finally,this paper identifies the geometric parameters of the robot by kinematics identification method based on distance error model,so as to improve the absolute accuracy of the robot.Firstly,the mathematical principle of calibration based on distance error model is introduced,and the feasibility of this method is analyzed from the theoretical point of view.Then,the research object of the four-axis robot in thispaper is specified,and its mathematical expression is multivariate statically indeterminate.Linear equations;we choose the least square method to find its approximate solution;finally,through the simulation analysis of MATLAB,we calibrate the pre-given geometric error parameters,and finally find that the absolute accuracy of the manipulator can be greatly improved.