Research on Robot Calibration Method Using Single PSD to Construct Local Line Constraint

The accuracy of industrial robots will decrease after long-term use, and field calibration of kinematic parameters is needed to improve accuracy. This article proposes a calibration method for industrial robots using unit position sensitive device(PSD) to construct local line constraint. Using an optical system composed of a single PSD to detect the imaging position of the point light source at the end of the robot, a vertical image plane line constraint is formed by constraining the imaging points to zero. Establish a kinematic error model for robots using the D-H rule and differential principle, and propose a parameter identification method based on local line constraint using the Levenberg Marquardt(LM) algorithm. By conducting prototype experiments and comparative experiments, the feasibility of the calibration method has been confirmed. The experiment shows that this method can effectively improve the accuracy of robots and is suitable for field calibration of industrial robots.