Non-iterative geometric method for cable-tension optimization of cable-driven parallel robots with 2 redundant cables

Aimed at addressing issues concerning the need for performing heavy calculations and difficulties encountered while determining cable tension in cable-driven parallel robots (CDPRs) equipped with 2 redundant cables, a non-iterative method for calculating cable tension feasible region (CTFR) is introduced herein. Additionally, several geometric methods have been proposed for cable-tension optimization of CDPRs based on CTFR from the perspectives of the lowest power consumption, safety optimization, and highest stiffness. The proposed methods employ geometric methods of calculation without the need for a large number of iterations. First, a calculation algorithm for cable-tension polygons based on Graham's scanning has been introduced followed by analysis of its time complexity to effectively obtain CTFR of CDPRs or demonstrate the singularity of CDPRs. Further, a new method has been introduced to evaluate the safety of optimization results. The said safety of results obtained via use of the proposed optimization methods based on CTFR has been evaluated and analyzed. Finally, a dual-thread PID force/position hybrid control method has been used to exercise real-time control over cable tension in CDPRs. Results obtained from experimental and theoretical analyses performed in this study verify the appropriateness and efficacy of the proposed approach.