High-accuracy visual/PSD hybrid servoing of robotic manipulator

This paper presents a new and effective multisensor based control strategy for high-accuracy/precision and high-efficiency automatic robot localization and calibration. The strategy combines both coarsely visual servo and fine position-sensitive detector (PSD) servo control methods. In a large field of view, an image-based visual servo control system is developed to roughly guide the laser beam, which is from a single laser pointer mounted at the end-effector of robot, to project to the high-resolution segmented PSDs. Once the laser spot is projected onto the active area of PSD, the control will be switched to the high-resolution PSD feedback and servoing for fine positioning. The experimental results conducted on an ABB industrial robot IRB1600 verify the effectiveness of the developed visual/PSD hybrid servo controllers as well as demonstrate that the high accuracy 30 mum of robot localization can be approached. The development of the hybrid control system and method will be a major step for achieving high-performance automatic robot calibration.