Checking the cable configuration of cable-driven parallel robots on a trajectory

This paper addresses the concept of cable configuration of cable-driven parallel robots (CDPR). At a given pose a cable configuration describes the state of cables, i.e. under tension or slack, and plays a major role for the cable tensions and the platform positioning errors. Being given a CDPR with non-elastic cables and a model for the coiling system we describe how the cable configuration can be determined in a guaranteed way for a desired trajectory of the platform. We show that if the CDPR has more than 6 cables it is extremely unlikely that more than 6 cables will be under tension simultaneously even under perfect conditions. It appears that on a trajectory the cable configuration exhibits multiple changes, leading to large variations in the cable tensions.