Design and Implementation of the Lower Extremity Robotic Exoskeleton with Magnetorheological Actuators

Abstract

Lower extremity paralysis tends to be common in recent years, and rehabilitation robots are developed to help patients recover. In this paper, a robotic exoskeleton is designed to provide rehabilitation training in two modes, including robot-active mode and human-active mode. Magnetorheological (MR) actuators are manufactured and set in the robot. In the robot-active mode, the MR actuator works as a clutch to transfer the torque generated by the motor to the leg joint, providing flexible torque instantaneously for human safety and reducing the power consumption. While in the human-active mode, the MR actuator functions as a brake to provide controllable damping torque to conduct anti-resistance training to help patients strengthen muscles. Biomechanical simulation based on AnyBody Modeling System (AMS) is also analyzed. Then, a human-robot interaction control method is proposed, where the effect of the MR actuators is taken into consideration, and experiments are conducted to verify effectiveness of the control strategy of the robotic system.