Abstract：In conventional researches, cables of cable-driven parallel robots are treated as simple linear cable elements. This results in the fact that the effect of cable dynamics on the positioning precision of the end-effector is not adequately taken in account. In this paper, a dynamic model for cable-driven parallel robots with cables of slowly time-varying length is presented. The partial differential equations characterizing the dynamics of a cable with time-varying length are deduced, and converted into ordinary differential equations using finite difference method for their spatial discretization. Then, the dynamics of cable-driven parallel robots are achieved considering the couple between dynamics of the end-effector and cables, in which the degrees of freedom of cables and the end-effector are all involved. Two numerical examples are presented to validate the dynamic model in the paper, and also show that it is necessary to take into consideration of the cable dynamics for robots of large workspace.
2011, Vol. 30 
