Reconfigurable fully constrained cable driven parallel mechanism for avoiding interference between cables

Abstract

Cable driven parallel mechanisms (CDPMs) have attracted much attention due to their many advantages over conventional parallel mechanisms, such as the significantly large workspace and the dynamics capacity. One of the main issues involved in designing CDPMs is avoiding cable-cable collision, especially when an operator is sharing the same workspace with the moving parts of the mechanism. This paper aims to model and simulate a reconfigurable fully constrained CDPM and solve the forward and inverse kinematics given that the attachment points on the rails move up and down in real time, unlike conventional CDPMs where the attachment points are firmly fixed on specific positions on the rails. The new idea of reconfiguration is then used to avoid interference between two cables in real time by moving one cable's attachment point on the frame to increase the shortest distance between them while keeping the trajectory of the end effector unchanged. This new approach was tested by creating a simulated intended cable interference trajectory, hence detecting and avoiding cable collision using the proposed real time reconfiguration while maintaining the end effector trajectory.