A specialized robot for ankle rehabilitation and evaluation

The main goal of this study was to develop a robot system for assisting rehabilitation of patients with ankle dysfunction. The whole robot system included the robot mechanism, AC servo motor, one-axis torque sensor, controller, safety measures and visual feedback device. A fuzzy position/force controller was constructed for angle and torque control. Three types of training movements were developed, including passive traction for reducing muscle tone, active tracking under constant external load for increasing muscle force and control capability and motor control training for increasing joint stability. Off-line analyses of data could be used to quantitatively assess the progress of rehabilitation. Three quantitative indices, corresponding to the three respective types of movements, were formulated. The robot system was tested in a small group (n=5) of normal subjects. The results indicated that the performance of the robot met the desired specifications and the proposed indices could be used to evaluate the performance of the training movements.