Cable-driven knee assistance robot for ascending gait

Abstract

When a human walks on level ground, the knee joint is structurally supported in the stance phase, allowing people to keep knee joints extended without much effort. However, when ascending a sloped gait environment corresponding to a staircase or a slope, humans have to exert a great deal of strength from the muscles that manage the knee joint. This makes people with gait disorders hard to ascend the slopes because they have issues generating precise and big torque from muscles. In order to guarantee the right to mobility in daily life for people with gait disorder, it is essential to reduce the energy consumption used in ascending gait and to decrease the knee joint torque requirement generated from the muscle. Therefore, in this paper, a cable-driven robot for assisting the knee joint in the ascending gait was designed for use in daily life. An inertial measurement unit(IMU) sensor was attached to the thigh for the application of the gait detection algorithm that adopts the angle and the angular velocity of the thigh. Then, predefined assistance at a predefined moment was provided in real-time. The performance of the robot developed in this study was evaluated with the measurement of energy expenditure and the measurement of muscle activity level. The result showed that the performance was better with assistance.