关键词: 手眼标定, 机器人磨抛, 复杂叶片, 重定位, 四元数法

Abstract: Relocalization-based eye-hand calibration algorithm was proposed to solve the problems of manual errors and quadratic errors in hand-eye calibration in robotic grinding systems. Taking the photographic 3D scanner as the calibration object, the hand-eye calibration mathematical model of the robot was analyzed, and then the calibration scheme was constructed by using the criterion sphere that moved around tool center point in robot end-effector coordinate frame. By virtue of the least square method, the relocalization center coordinate in the scanner coordinate frame was calculated, both translation vector and rotation matrix were calibrated by using the quaternion-based multi-space points coupling, and then the conversion matrix from scanner coordinate frame to robot base coordinate frame was obtained. Both of the hand-eye calibration and blade grinding experiments shows that the sphere fitting radius deviation of the proposed algorithm reduces to 0.068 mm, which is reduced by at least 38% compared with the existing algorithms. Meanwhile, the average blade surface roughness value Ra after grinding is reduced to 0.273 μm from the value of 2.5 μm after milling operation, and the profile errors reach within ±0.08 mm, which meet the technical requirements, thereby the proposed method is verified to be effective and accurate. 

Key words: hand-eye calibration, robotic grinding, complex blade, relocalization, quaternion-based algorithm