Graded Error Compensation Method for Heavy-Load Manipulators Based on Laser Tracking Measurement

In order to meet the high positioning accuracy requirements of industrial application scenarios for manipulators, the motion accuracy of industrial manipulators is generally improved through error compensation. However, due to the presence of non-geometric errors such as friction and joint backlash, error compensation is usually a complex nonlinear problem. Therefore, the existing methods of improving the absolute positioning accuracy of manipulators through model parameter calibration are difficult to obtain good performance, especially for heavy-load manipulators. To solve the above problems, this manuscript proposes a graded error compensation method for heavy-load manipulators based on laser tracking measurement, which realizes the compensation of kinematics error and joint stiffness, and improves the positioning accuracy of the manipulator in the entire workspace. Firstly, the geometric parameters were modeled and compensated by combining the distance model and the Denavit-Hartenberg (DH) model. Then, joint stiffness errors were studied and compensated. Finally, experiments were conducted on a heavy-load manipulator to verify the feasibility and effectiveness of this method.