A Two-Stage Parameter Identification Method and Compensation Verification for Heavy Load Robot

Kinematic calibration plays a significant role in improving the robot positioning accuracy. Due to the mechanical factors such as joint deformation and heavy load, some errors are non-geometrical and nonlinear. In this case, a single kinematic calibration method is difficult to achieve good results especially for robots with heavy load. In this paper, a two-stage parameter identification method is proposed, which also deals with joint deformation and heavy load dependent errors to achieve a higher positioning accuracy. In the first stage, the method builds the kinematic model and identifies the geometric errors using the DH model and the distance model. In the second stage, the stiffness of the joint is analyzed and the positioning accuracy is improved on the robot dynamics. Finally, the experiments are carried out on the 6R robot with heavy load. The experimental results demonstrate the effectiveness and correctness of the method.