Modeling of Elastic-Flexible Cables with Time-Varying Length for Cable-Driven Parallel Robots

Abstract

Cable-driven parallel robots use elastic-flexible cables for operation due to their advantages over rigid-link joints. In state-of-the-art modeling of cable-driven parallel robots, cables are mostly kinematics based and contain no explicit consideration of their dynamics. Experimental observations show these simplifications do not hold true in various scenarios where the cable-driven parallel robot becomes uncontrollable. We revisit the kinematics-based cable models and present a cable model empowering Cosserat rod theory for which the deflected configuration is formulated through higher-order Bézier curves. Numerical time integration of the dynamics is performed using an energy-momentum conserving integration scheme. The applicability of our cable model is exemplified on a planar cable robot with 3 degrees of freedom.