The variable position of the load’s centre of mass relative to the load’s hanging point of the CPR system

Abstract

This paper deals with the analysis of the position of the load’s centre of mass relative to the load’s hanging point during the motion in the workspace of Cable-suspended Parallel Robot – CPR system. It will be proven that the distance between the load’s centre of mass and the hanging point is variable during the motion. Also, their relative positions are variable as well. This phenomenon can be present at any type of CPR system, whose workspace can have a shape of: parallelepiped, triangle or line (planar example). The CPR system carries the load via pulleys and ropes. This analysis is valid for any construction of the CPR system where the load is carried with ropes and each rope is wound (unwound) on the corresponding system motor – winch. The ropes are hanged on highest points of the CPR system’s workspace.