Development of a high payload cable-driven parallel robot

A cable-driven parallel robot (CDPR) consists of elastic cables instead of rigid links. The lightweight of cables enables the CDPR applications for high payload, high speed and large workspace. However, the elongation of polymer cables can cause positioning error of the end-effector (EE) especially for heavy material handling application. In this paper, we propose an open loop load compensation algorithm to increase the relative accuracy of a CDPR. Since the force distribution of cables and cable lengths are different in different EE position, the elongation of cables will be different. Therefore, the algorithm are implemented with three different height (600, 800 and 1000mm) in straight line path. The payload of the robot system is 190kg. The experiment result shows that the root mean square error (RMSE) of EE position are 30.02mm for without load compensation and 0.65mm for with load compensation.