Analysis of stiffness controllability of a redundant cable-driven parallel robot based on its configuration

Abstract

To examine the influence of the configuration of a cable-driven parallel robot (CDPR) on its stiffness and stiffness controllability, a concept for a cable tension constraint workspace (CTCW) of CDPRs is introduced. Using a static force analysis, a static CDPR model was established and its stiffness model and a method for optimizing the cable tension were reviewed. To analyze and appraise the CDPR global and local stiffness controllability, a new concept of stiffness controllability degree is proposed and defined. In addition, a calculation method is proposed that uses the cable tension feasible region to effectively obtain the CTCW of the CDPRs according to the cable tension constraint condition. The driving cable layouts of the various CDPR configurations were optimized to maximize the CTCW volume as a performance index. In addition, the stiffness and stiffness controllability of each configuration CDPR were analyzed. The results of the theoretical and experimental analyses validated the efficacy of the presented method and serve as reference for the use of robots in practical applications or for design optimization.