Type Synthesis and Analysis of Reconfigurable Modules for Closed-Loop Cable-Driven Mechanisms Based on Geometric Constraints

Abstract Cable-driven mechanisms, particularly in closed-loop configurations, have demonstrated significant advancements in flexible drive systems. However, the cable tension changes caused by the closed-loop configuration cannot be effectively compensated. Relevant concerns, such as inadequate responsiveness or compromised control accuracy, consequently emerge. This study presents a method for synthesizing a family of isosceles trapezoid mirror symmetry modules, ensuring stability in cable tension. The geometric properties of an isosceles trapezoid form the fundamental principle for type synthesis. Combined with more geometric configuration, the closed-loop cable-driven mechanisms are constructed with stable structural constraints. Through mechanical theoretical analysis, the geometric and kinematic properties are thoroughly investigated and precisely formulated, thereby revealing the inherent singularity and bifurcation behaviors. Furthermore, several prototypes of the proposed modules have been fabricated to validate their kinematic properties. It demonstrates that the structural constraint of the cable has no influence on its tension. In addition, the proposed method can be extended to the design and construction of cable-driven manipulators, which hold potential applications in fields such as robotics and aerospace exploration.