Use of Depth Camera for Motion Tracking of Cable-Driven Parallel Robot Intended for Functional Rehabilitation

This paper addresses the development of a position control system for a planar cable driven parallel robots (CDPR) made out of four cables in order to drive the moving platform (MP) in the plane. The main target application of our control and tracking system is functional rehabilitation. The kinematic control model is implemented such that angular joints feedbacks are processed via encoders and the moving platform pose is retrieved through a depth camera. Due to the complexity of the forward kinematic and the uncertainties on cable lengths, direct 3D tracking of the MP is very valuable. First, the kinematic model as well as the inverse kinematic computing of the CDPR are presented. Then, the method of MP motion tracking and pose computing are described. Finally, an error analysis is conducted on both: the joint trajectories and the cartesian trajectory of the MP.