Design and modeling of motion-decoupling mechanism for cable-driven joints

Abstract

With the advantages of simple structure, low power consumption, high ratio of load to self-weight, and good flexibility, the cable-driven robots are especially suitable for medical instruments and home service. Due to the alignment of cables, there is a problem of motion coupling between the manipulator joints, leading to the degradation of control accuracy. Moreover, the hysteresis and the dead zone of the cable driving unit make it difficult to control the joint accurately. To effectively solve above-mentioned motion-coupling problem, a novel motion-decoupling mechanism is proposed and investigated. An experimental setup is established to verify the kinematic decoupling characteristics. Based on the “static friction + Coulomb friction” model, the friction model is established and verified. Thus, studies on the friction model have provided theoretical basis for the accurate force coordinated control of the cable-driven system.