The Effective Action of Cables During the Rotation of the End Effector in a Planar CDPR

Their large positioning workspace characterizes the cable-driven parallel robots (CDPR). However, the orientation that the end effector can develop presents limitations that depend on the configuration of the cables in its fixed structure, such as in its mobile structure. These limitations may be geometric, related to the limit prior to cable entanglement, or physical limitations related to the forces the cables exert to reach the required orientation. As the orientation develops, the cables must change the magnitude of the action, and in some instances, some of them must stop acting or failing that, they must begin to act if they did not do so before; in this way, the joint action of all will allow rotating the end effector (EE) of the robot towards a proposed value. In this work, a strategy is proposed to geometrically identify the effective action (corresponding to the sign of the control signal for each cable) that each robot cable must execute while the rotation of the EE is developing. The simulations are carried out in MATLAB, with Simulink and Simscape, the results of which have allowed us to verify the effectiveness of the proposal, making the rotation of the end effector more flexible with a notably better performance compared to a traditional rigid proposal that does not consider an instantaneous analysis of the condition of rotation of the EE.