Design of a rehabilitation device based on a mechanical link system

Realizing an ideal impedance control system in lower extremity rehabilitation systems is challenged by mechanical impedance of robot hardware. Although some studies in the field of control systems have been helpful in reducing the mechanical impedance of actuators, they have not been able to remove the inertia of robot hardware. This paper introduces an alternative design in which mechanical links are utilized. The mechanical links are driven by one actuator without any complicated servo systems. The design parameters are optimized for the link system to generate the normal walking motion. The simulation data shows that the normal gait patterns are realized successfully. The device is connected to a patient using elastic components, and therefore the inertia of the robot is not directly imposed on the patient. The patient's legs are guided to follow the motion of the robot with the forces generated by the elastic components.