| The positioning precision of the robot is divided into re-positioning precision and absolute positioning precision, in the field of off-line programming, repetitive positioning accuracy is higher. Off-line programming technology becomes more and more popular in all walks of life now, but it fails to reveal the error between robot theoretical position and actual position. Although absolute positioning accuracy is improved, it only shows that the robot parts have enough compactness and the testing equipment have enough resolution ratio.This paper, for the actual geometrical structure characteristics of industrial robots,used D-H method to analyze in detail, using the modified D-H method to establish mathematics error model of the robot kinematics and finding its solution, established the jacobian of the geometric parameter of partial differential matrix equation error calibration.Secondly, regarding the error source of the industrial robot, the linear error calibration model, based on the MATLAB software system compiled the positive and inverse solution of robot kinematics, collected multiple sets of data to linear system of equations using least squares iterative, error compensation, correction, verifying the feasibility of the robot parameter identification algorithm.Finally, by analogy to the indirect calibration method and the direct calibration method of the advantages and disadvantages, the laser tracker for direct measurement of robot end actuators established, then the error between actual location and theory location was corrected. Based on the first modification,the second iteration correction algorithm implemented, the convergence of parameter error was confirmed. From the point of error theory, three methods of calibration results were evaluated, which effectively improve the absolute positioning precision of the robot. |
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