Elastodynamic analysis of cable-driven parallel manipulators considering dynamic stiffness of sagging cables

Abstract

This paper focuses on the elastodynamic analysis of cable-driven parallel manipulators. Dynamic stiffness matrix of a single sagging cable is introduced. This matrix considers the effect of both cable mass and elasticity. Dynamic response functions are evaluated for cable-driven parallel manipulators. As an example, the dynamic analysis of a 6-DOF cable- suspended parallel manipulator is achieved considering the dynamic behavior of sagging cables. Numerical simulations and tests are demonstrated to validate the model by identifying the natural frequencies. Effects of cable sag on the static pose error are also experimentally investigated. Results show the importance of taking into consideration the cable dynamics for cable-driven parallel manipulators when it comes to perform applications such as high speed pick-and-place or large working volume. I. INTRODUCTION Cable-driven parallel manipulators (CDPMs) are a special variant of traditional rigid-link parallel manipulators. Using flexible cables rather than rigid links has lots of advantages, such as higher dynamics due to smaller moving mass, much larger workspace, and lower cost. However, as cables present the particularity of not being rigid and are only able to act in tension, the stiffness of CDPMs becomes a vital