Research On Analysis Methods For Pose Accuracy And Reliability Of An Arc Welding Robot

Robot pose accuracy is an important indicator that measures the working performance. The analysis of pose error is the premise to achieve precision control. And it is the base of compensation for its pose error and trajectory error. It is assurance that robot can noramlly work,be high precision operated and be directly related to the production efficiency. So the pose accuracy of the robot has very important theoretical and practical significance.This paper is to analysis and study of the reliability for pose accuracy of the arc welding robot, including selection and calculation for the performance parameters of arc welding robot, modeling for the pose error, the calculation and analysis to the end of robot caused by each joint,analysis of attenuation model,the solution of workspace and so on.To select the appropriate performance parameters for robot according to national standards of industrial robots,and analysis and processing the test datas for the performance parameters,including:remove gross errors,mapping data distribution histogram and track images etc,determine the type of data distribution, and calculate each selected parameter value. Then design an application software interface for analysising and processing the test datas and calculating performance parameters,using Matlab and Gui.To establish the position and orientation error of the robot,using of matrix differential method, on the basis of the robot kinematics.To solve the pose errors caused by each joint in two forms:firstly,the error of each joint is known;secondly,the error distribution of each joint is known.To analyze the reliability of the error of the end after solving the robot end error caused by various joints of the robot.This paper gives two methods for solving the reliability of error:firstly,make use of statistics based on Monte Carlo sampling methods;secondly,to determine the distribution of error type,then calculate the reliability of end error using the corresponding cumulative probability distribution function. Then to solve the robot work space using numerical method based on Monte Carlo sampling algorithm.During normal operation of the robot joints may occur in the analysis and calculation of wear. This paper considers only the work of normal and stable phase of the robot joints wear, that is the case of linear wear of decay. Assuming each joint error is normal distribution within the error circle,then use Monte Carlo method for sampling the value of the corresponding sampling error can be calculated after each wear attenuation Error of joint to the end and the end point error analysis of reliability.The arc welding robot pose accuracy reliability analysis software system is developed based on Matlab platform, with the function:calculate robot performance parameters, calculate and analysis of reliability of the end of robot pose error,solve work space and so on. Commissioning results show that the system is stabile, meet the performance demand, easy to operate.