An inverse kinematics method for robots after geometric parameters compensation

作者：Li, Gongfa; Xiao, Fan^*; Zhang, Xiaofeng; Tao, Bo; Jiang, Guozhang

来源：Mechanism and Machine Theory, 2022, 174: 104903.

DOI：10.1016/j.mechmachtheory.2022.104903

• Robot
• Inverse kinematics
• Geometric errors
• Spherical wrist
• Newton-Raphson

It is difficult to apply the inverse kinematics (IK) of the nominal model of robots directly after the error compensation of geometric parameters. This paper proposed an instruction pose-based compensation method to overcome this problem. Its principle is very simple: the pose error between the calibrated model and the nominal model is compensated to the instruction pose, and then the new instruction pose is solved by the IK algorithm of the nominal model, and the above steps are repeated until the termination condition. According to the principle, we obtained the final iterative expression of the pose error and determined its convergence conditions and convergence. Experiments on the calibrated spherical-wrist and non-spherical-wrist robots show that the theoretical analysis is correct. It is concluded that the calibrated robot could be simplified into a structure with an analytic solution. Then, the IK of the original robot can be obtained by nesting the analytic solution into the proposed method. The proposed method can converge the pose error norm to the order of 10-10 in only a finite number of iterations and takes less time than the Newton-Raphson algorithm.