Non-contact coordinate measurements for robotic manipulators using laser tracking systems

Laser Tracking Systems (LTSs) are adopted as high accuracy instruments to measure robot performances such as repeatability and accuracy. In this paper, a LTS is used as a sensor to measure the three-dimensional coordinates of the end-effector, estimate the link lengths, check the parallelity and perpendicularity between axes and calibrate the home positions of a robotic manipulator. In addition, by using the LTS as a position sensor, through feedback compensation, we can drive the end-effector of the robotic manipulator towards the target. Experimental results show that the proposed control system can achieve precise positioning accuracy for a robot with or without an accurate model.