It is necessary to recalibrate the tool coordinates when replacing tools in the application of industrial robots. Generally, constrained by a fixed point, the tool coordinates are calibrated by the threepoint method. This method will get a bad result when the home position of the robot is not accurate. Based on the principle of fixedpoint constraint in the threepoint method, an improved home position selftuning method for industrial robots was proposed. The calibrated 6-DOF serial robot was used as the experimental object, and the given error was generated by modifying the standard value of its home position and tool coordinate. Based on the constraint relationship of a fixed point in the space, the coordinate transformation model of the robot was established under the condition that the parameters of the robot link were known, and 21 groups of robot joint angles and Cartesian coordinate data were taken as the identification condition parameters.The deviation between the tool coordinate and the home position was regarded as unknown data, and the deviation between the tool coordinate and the home position was calculated by leastsquare iteration algorithm. Compared the experimental result with the given error parameter, the result is basically consistent. The feasibility of the calibration algorithm is proved by comparing the error of the position display value on the teaching device before and after selftuning state.
HE Yingwu, MEI Jiangping, HUANG Xuanqing, CHEN Mianpeng, ZHENG Donghai. Improved Home Position Selftuning Method of Industrial Robot Based on Tool Coordinate Calibration [J]. Machine Tool & Hydraulics,2021,49(5):14-19