Research On Robot Calibration Technology Based On Distance Error

As robots are increasingly used in industrial production,the requirements for their positioning accuracy are increasing.In view of the shortcomings of the low absolute positioning accuracy of industrial robots,this thesis investigates the robot calibration technology by improving the absolute positioning accuracy of KUKA KR 16 industrial robots as the research object.This paper focuses on the four steps of modeling,measurement,identification,and error compensation,the following work was carried out:（1）The kinematic analysis and modeling based on the KUKA KR 16 type robot were completed.The MD-H model were used for kinematic modeling,and on this basis,the relationship between the absolute positioning accuracy error of the robot and the error of the robot linkage parameters were constructed based on the theory related to the differential kinematics of the robot.（2）Aiming at the transformation error of coordinate system in the position error model,the distance error model was used.The relationship equation between robot distance error and absolute positioning accuracy error were derived,the distance error calibration model was established,and the error model was analyzed for redundancy of error parameters and redundancy parameter rejection.（3）The optimal number of positional points for parameter identification was determined based on the observable index of O₁.For the problem of unstable parameter calibration results caused by random pose points in the process of industrial robot calibration,an optimization algorithm of measurement pose point set was proposed to screen the optimal pose set for parameter identification.The least squares algorithm and the L-M algorithm were used for parameter identification,and the parameter identification algorithm and process were designed.The distance error of the robot was calibrated to verify the validity of the distance error model and the discrimination algorithm.（4）A calibration experiment platform based on a KUKA KR 16 industrial robot and a FARO Vantage E laser tracker was built,and the data obtained from the measurements were used to identify the parameters and verify the identification results of the robot calibration method used in this paper.Based on the calculation results,it was verified that the calibration method selected in this paper can effectively improve the absolute positioning accuracy of the robot.