Design and Analysis of a Rolling Joint Based on Tension Amplification

Owing to structural rigidity and inherent quality issues in traditional industrial manipulators, attaining essential safety in man-machine cooperation proves challenging. In this study, we emulate the human arm tendon drive principle, positioning the motor, reducer, and other high-quality components behind and driving them with cables. To address the stiffness issue in low-mass manipulators, we design the structure of a bilateral conjugate gear rolling joint using a pulley tension amplification mechanism. Analyzing the designed rolling joint, we unveil the kinematic relationship between cable length and joint angle. Simultaneously, we derive expressions for the stiffness and strength of the rolling joint, laying a theoretical foundation for subsequent joint optimization. We have also analyzed the overall pulley system and derived the tension transfer. Conducting kinematics simulation with the Adams simulation software, we unveil the impact of the number of turns on the joint angle. The observed motion results align with the theoretically derived outcomes.