Motion-Assist Robot for the Lower Limb to Rotate and Correct Movement of the Knee

In recent years, exoskeleton robots have been developed to support walking and rehabilitation in the elderly. These robots are attached directly to the body. They offer support by giving torque to the knee joint. However, the elderly person often has abnormal rotation of the knee due to motor system disease. Thus, it is necessary to consider the rotation of the knee in the development of such robots. In this study, we develop a motion-assist robot for the lower limb to rotate the knee. The movement of the knee that rotates the thigh inward as the leg extends from 30 degrees to full extension is called the screw home movement. Abnormal rotation in an elderly person with motor system disease is corrected by having the robot rotate the thigh inward. The walking support system uses a motor and bevel gear. In addition, we developed the orthosis to transmit the power assist from robot. A controlling motor was used to extend the motion-assist robot for the lower limb so that it could be evaluated. Results of the experiment were determined using a motion-capture system, and they confirmed that the developed rotation mechanism of the robot rotated the thigh.