Time-Varying Nonnegative Control for Cable Driven Parallel Robots

Abstract

In this note we propose new time-varying nonnegative control laws for the cable driven parallel robots (CDPRs). For these latter, it is well known that the challenge is to be able of only pulling the cables (can not pushing them) so that the end-effector follows a desired trajectory with fast convergence. The control design is established after study of different modes of motions of the CDPR, and by the use of several non-linear transformations. From the controllability analysis, we propose a simple and efficient time varying controller and show how to set some key parameters. We have also defined, in the same spirit, a time-varying Lyapunov function and show exponential convergence to a desired trajectory. High performances of the proposed approach are shown through simulation results.