Design and Dynamic Analysis of a Bio-Inspired Rolling Joint Manipulator Based on Pulley-Cable System

Cable-driven joints have gained widespread use in various applications, yet the inherent limitations in cable stiffness and strength pose challenges in ensuring joint stability and operational safety. Enhancing joint stiffness and predicting cable tension changes during motion are essential to mitigate the risk of cable breakage. This article presents the design of a novel bio-inspired rolling joint manipulator, featuring a single-motor-driven pulley transmission system with symmetrical tension amplification. A novel cable winding drive mechanism with integrated tension detection is proposed. The tension distribution across the pulley system is analyzed via the classic Euler equation. A comprehensive system model is established, spanning from the motor-driven winch, through the guide pulleys, to the load-bearing tension amplification pulley. By incorporating the derived tension distribution into the kinematic and dynamic equations of the joint, the model accurately predicts how cable tension evolves during joint movement. The theoretical formulations and tension distribution are validated through both software simulations and prototype experiments, demonstrating high consistency. The results confirm that the dynamic model proposed in this article is more accurate and comprehensive, considering friction and tension transmission.