Field Calibration Method for Industrial Robots Based on Single Position Sensitive Device

Abstract

Field calibration of industrial robots is a crucial technology that is essential for ensuring the proper utilization of robots. This paper proposes a field calibration method based on single position sensitive device (PSD) for industrial robots to address the problems of poor environmental conditions and high equipment costs for robot field calibration. Firstly, we analyze the monocular vision six-degree-of-freedom spatial position estimation method and explore the "3-point" spatial position measurement model for robot calibration. We apply the standard D-H rule and partial differential equation theory to establish the forward kinematic model of the six-axis industrial robot and its error model. Subsequently, we construct a calibration method for the "3-point" spatial position measurement model. Finally, we develop a calibration prototype based on a single PSD industrial robot and perform calibration experiments on the CRP-RA07 robot platform. The results show that the root mean error of the robot position after calibration by the field calibration method proposed in this paper decreases from 2.520mm to 0.254mm, with an accuracy improvement of 89.9%; The laser tracker measured the position error of the robot before and after calibration without tool flange, which decreases from 1.133 mm to 0.114 mm, improving the accuracy by 90.0%. Furthermore, we verify the effectiveness of the proposed calibration method by comparing the results of calibrating the robot using a laser tracker with the results obtained using this method. This calibration method exhibits several advantages, such as lightweight construction, low equipment cost, and high accuracy after calibration, making it suitable for field calibration of industrial robots.