Error analysis and flexibility compensation of a cable-driven humanoid-arm manipulator

Kinematic calibration is an effective method for improving the accuracy of the robot motion control. For the cable-driven robot, the flexibility of the cable makes the robot have good compliance and meet safety requirements; however, it brings a greater influence on the movement accuracy of the mechanism. Thus, kinematic calibration alone cannot accurately establish the error model. In view of the error analysis and flexibility compensation of the cable-driven robot, this paper analyzes the effect of flexible rope on kinematic movement accuracy by introducing a flexibility compensation weighting factor. A kind of comprehensive error analysis model of the cable-driven robot was established. By using kinematic calibration algorithm, it organically merges together the kinematic errors caused by the geometric parameters errors and that caused by flexibility of cable. With shoulder joint of the cable-driven humanoid-arm manipulator as the experimental object, the results showed that the algorithm has a better convergence, and it can effectively improve the accuracy of the robot motion control.