A Three-Cable Driven Planar Parallel Robot: Closet Set Searching Kinematics and Model Reference Adaptive Control

Abstract

Cable-driven parallel robot (CDPR) has advantages including a reconfigurable workspace and lightweight actuators. The goal of this study is to develop a three-cable driven planar parallel robot that can be utilized for upper arm exercise toward routine practice. To make a repetitive practice motion on a patient's desk, we designed and prototyped a robotic system based on the three-cable driven planar parallel robot that can minimize the number of cable and related parts. Forward kinematics is derived with a novel closet set searching method and a model reference adaptive controller is designed for the desired trajectory tracking. The experimental results show that the root mean square error (RMSE) was 2.17 and 2.09 mm for a circle trajectory and 1.33 mm and 3.29 mm for a line trajectory, along with the x- and y-axis. We could confirm that the prototyped three-cable planer CDPR has the possibility to adapt in routine exercise or rehabilitation requiring repetitive motions with easy installation.