Cable vibration analysis for large workspace cable-driven parallel manipulators

Abstract

Cable-driven parallel manipulator is one of the best solutions for large workspace applications. But when long-span cables are involved the effect of cable vibration on the positioning precision of the end-effector should be carefully evaluated since these cables are prone to vibration, degrading the performance of manipulators. In this paper a dynamic model of cable-driven parallel manipulators is presented where each cable is divided into several elements to account for cable vibration. A simple linear cable element is presented where nodal force is related to both nodal position and element length to involve the effect of cable length variation. Numerical examples are presented to demonstrate the effect of cable vibration. The results show that it is necessary to take into consideration cable dynamics for manipulators operating at high speed and vibration of cables can shorten their corresponding chord length.