Biomechanical Design of a Passive Knee Exoskeleton for Adaptive Walking Assistance.

This paper designed a wearable exoskeleton to assist knee joint. We analyzed the anatomical structure and locomotion mechanism of knee joint by OpenSim, and found that knee flexion angle was less than 60° during level walking, and the higher the stair was, much greater the force of knee extensor was. An adaptive passive exoskeleton was developed, which allowed the knee joint move freely during level walking. While climbing stairs, as the flexion angle was more than 60°, it stored energy when the knee bends, after then to assist knee extending. Comparison experiments based on the measurement of sEMG signals demonstrated that the exoskeleton reduced the muscle activities of knee extensor in all situations. The greater the bending angle of the knee joint, the more obvious the assisting effect was. The proposed passive exoskeleton has an adaptive walking assistance effect, it can reduce the muscle fatigue of knee joint.