Analysis of cable tension of high speed parallel cable robot: High speed position tracking of winch

Cable-driven parallel robots have a wide range of applications due to its unique characteristics of large workspace and high payload and dynamics. One of its promising industrial applications is high speed material handling allowed by high dynamics of the cable robots. The high speed material handling has been mostly performed by traditional parallel robots, such as delta robots whose workspace and speed are limited by the length and weight of the rigid links. Utilizing the characteristics of large workspace and high dynamics, a high speed cable robot is able to achieve high speeds over large workspace. However, high acceleration together with inertia for high speed manipulation can degenerate winch position tracking performance, which, in turn, causes tension distribution change. To achieve good performance at high speeds, it is desired to analyze and minimize the effects of the winch position tracking errors on tension distribution. In this paper, the effects of the position tracking error on tension have been analyzed. It is observed that approximately one half of tension error can be caused by the position tracking error during high speed manipulation.