A novel optimal calibration algorithm on a dexterous 6 DOF serial robot-with the optimization of measurement poses number

Normally, people always believe that the more measurement poses used in a robot calibration process, the more accurate result can be obtained. However, the accuracy improvement converges to a threshold after a number of measurement poses. Moreover, robot calibration is a time consuming process, too many poses would seriously complicate the process and consumedly increase the spending time. In this paper, an optimal measurement pose number searching method was proposed to improve the calibration method in time spending aspect. Optimal robot poses were added to an initial pose set one by one to establish a new pose set for the robot calibration. The root mean squares (RMS) of the end-effector pose errors after being calibrated by using these pose sets were calculated. The optimal number of the configuration set which correspond to the least RMS of pose error can then be obtained. This algorithm can get higher end-effector accuracy, meanwhile consume less time. The simulation on a serial robot manipulator with 24 unknown kinematic parameters shows that the end-effector pose accuracy after calibrated by the using of the optimal pose set is much better than the result before calibration, and is better than the using of a random pose set.