Optimal Reconfiguration Planning of a 3-DOF Point-Mass Cable-Driven Parallel Robot

Cable-driven parallel robots (CDPRs) have attracted much attention due to their advantages, such as large workspace and excellent load capacity. However, their adaptability to different tasks has been limited because of fixed configurations. To improve this, a novel three-DOF point-mass reconfigurable CDPR (RCDPR) has been designed, and its configuration can be changed by adjusting the positions of multiple cable anchors. Since wrench feasible workspace (WFW) is an essential criterion that describes the configuration characteristics, an optimal reconfiguration planning method is proposed to schedule the sequence and number of all movable cable anchors for adjusting the WFW range. Based on a two-level optimization process, the method can realize static reconfiguration (SR) or dynamic reconfiguration (DR) of the RCDPR. If SR cannot provide the required WFW by finding a static optimal configuration, the WFW range will be dynamically adjusted by DR. Besides, the number of movable cable anchors is minimized in DR by applying L-1-norm optimization to the anchor velocity sequences. Simulations and experiments are implemented, and the results show that the proposed method can automatically determine when, which, and how the cable anchors move under physical constraints, and reducing the number of movable cable anchors can indeed save actuator energy effectively.