Drilling errors compensation of industrial robot based on 3D passive scale tracker

Abstract

In order to increase the machining accuracy of industrial robots, a drilling system based on a 3D passive scale tracker (3DPST) and Epson industrial robot was established. The real-time positioning errors of the robot were measured by 3DPST, and the orientation errors were analyzed according to position coordinates on a circular path. Therefore, the 6-DOF pose errors of the robot were measured. Building upon this foundation, a cyclic compensation method for robot pose errors was proposed. This method prioritizes the compensation of orientation errors followed by the compensation of positioning errors. Robot circular path tests and drilling experiments of aluminum alloy and plexiglass materials are carried out to verify the effectiveness of the error measurement compensation method. The results of Coordinate Measuring Machine (CMM) measurements indicate that, after robot error compensation, the machining accuracy of the machined holes in both materials is significantly improved. The positioning errors of the machined holes for aluminum alloy decreases from the range of 1.188~1.576 mm to 0.154~0.215 mm, while for plexiglass, it decreases from 1.226~1.437mm to 0.132~0.183 mm.