A Robotic Spindle End High-Accuracy Positioning Method Based on Eye-in-Hand Vision Active Correction

Robot end-effector positioning is crucial for performing high-accuracy tasks. This article proposes a novel method for achieving online high-accuracy positioning of the spindle end based on the eye-in-hand active correction. The positioning process includes the working area locking based on the feature recognition and the coordinate high-accuracy positioning. For the latter one, first, a new hand–eye calibration approach is introduced to acquire the relationship between the cameras and the robot end without being constrained by the public field of view (FoV) of the binocular cameras to establish accurate transformation for positioning process. Second, the spindle end is positioned to achieve an accurate position by repeatedly updating the difference between the current position and the preset coordinate with the active correction of the eye-in-hand vision assisted by local machining reference points. Experimental results indicate that the proposed method can reduce the absolute positioning error of the spindle end from 0.098 to 0.078 mm, which is reduced by 20% compared with the laser tracker (LT) method.