Stiffness analysis of a planar 2-DoF cable-suspended mechanism while considering cable mass

Abstract

The mass of the cables is not considered in most existing research on cable-driven mechanisms (CDM). Moreover, of those papers where cable mass is considered, few have examined its effects on mechanism stiffness. The research presented herein seeks to better understand these effects with regards to a planar two-degree-of-freedom suspended CDM. The mechanism’s stiffness matrix is first developed and then used to generate mappings of intuitive stiffness indices over the workspace. The sagging of the cables under their own weight is found to heavily influence mechanism stiffness. The importance of maintaining a minimum level of cable tension to minimize the effect of cable sagging on the mechanism’s stiffness and workspace is also demonstrated.