Design, modeling and position control of a wrist rehabilitation robot based on Stewart platform

In this paper a new application of Stewart platform is developed for rehabilitation utilities. Stewart robot has a good workspace and load capacity similar to other parallel robots. Here the Stewart model is modified in order to be employed as a wrist rehabilitation robot and is controlled using a nonlinear position approach. To meet this goal both the direct and inverse kinematics of the robot is extracted using Jacobian matrix. Afterwards, the related dynamic model of the proposed robot is developed using virtual work method. In order to keep the wrist of patient within the desired path of rehabilitation, a nonlinear position control is designed and implemented on the robot using Computed Torque Method (CTM). By the aid of conducting some analytic simulations in MATLAB the applicability of the proposed robot for wrist rehabilitation is demonstrated. The verification of the model is performed by comparing the results with previous articles while the efficiency of the implemented controller is proved by comparing the actual path with the desired one in presence of disturbance. It is shown that by the aid of the proposed robot and controller, the wrist rehabilitation process of a patient can be successfully accomplished.

Keywords:

Rehabilitation robot , Stewart parallel robot , Virtual work , Kinematics , Dynamics , CTM controller