Tension Distribution and Dynamics Analysis of a Cable-driven Humanoid Wrist

Abstract

In order to simulate the structure and function of human arm and wrist joint, a 3-DOF(degree-of-freedom) cable-driven humanoid wrist is put forward, which is different from the traditional bionic joint, its function is achieved by a ball joint which connects the moving base platform and the base. However, the introduction of cables increases the difficulty in modeling and control. Firstly, ignoring the gravity property of the cable, the standard dynamics equation of the humanoid-wrist joint is built by using Lagrange method. At the same time, taking into account the redundant actuation and single-direction force for the cables, the cable tension distribution optimization model is established, and the cable tension distribution is obtained by genetic algorithm. Secondly, aiming at the influence of the cable mass, a more accurate dynamics model is established by considering catenary. Finally, the two models are simulated and the simulation results are compared.

Keywords

• Cable-driven