Position Control of a Fully Constrained Planar Cable-Driven Parallel Robot With Unknown or Partially Known Dynamics

In this article, we propose an intelligent proportional-integral-derivative (iPID) controller to control the position of a planar cable-driven parallel robot (CDPR). The proposed control method is based on ultralocal model estimation in short time intervals using only the system input-output behavior. We first employed the reference model-free iPID control, which requires the complete system dynamics estimation for the robot. Then, we modified the controller to utilize the partially known system dynamics represented in the feedback linearized form of the nonlinear model. Only the remaining unmodeled dynamics are estimated with the modified controller. We experimentally investigated the classical model-free intelligent proportional and derivative (iPD) controller and the modified iPD controller performances on the planar CPDR. The results show that significant performance improvement is achieved with the modified iPD controller.