Kinematic calibration of manipulator using single laser pointer

This paper proposes a robot kinematic calibration system including a laser pointer installed on the manipulator, a stationary camera, and a planar surface. The laser pointer beams to the surface, and the camera observes the projected laser spot. The position of the laser spot is computed according to the geometrical relationships of line-plane intersection. The laser spot position is sensitive to slight difference of the end-effector pose due to the extensibility of laser beam. Inaccurate kinematic parameters cause inaccurate calculation of the end-effector pose, and then the laser spot position by the forward estimation is deviated from the one by camera observation. For calibrating the robot kinematics, the optimal solution of kinematic parameters is obtained by minimizing the laser spot position difference between the forward estimation and camera measurement via the nonlinear optimization method. The proposed kinematic calibration system is cost-efficient and flexible for any manipulator. The proposed method is validated by simulation and experiment.