A Hip-driven exoskeleton for Walking Assistance based on a Clutch-type Elastic Actuator

The paper combines the characteristics of the exoskeleton's power and the patient's residual capacity, and proposes a clutch-type elastic actuator (CEA) based on ratchet pawl mechanism, which organically couples the elastic energy storage element with the motor drive as the hip joint actuator of the exoskeleton. The actuator takes advantage of the slow gait speed of the patient. During the support phase, the patient tries himself/herself to shift his/her center of gravity with the help of crutches, while the motor stores energy in the torsional spring; during the swing phase, the torsional spring quickly releases energy to help the patient flex his/her hip and swing his/her leg. Also a hip-driven exoskeleton based on the CEA is developed and the assist effects of the exoskeleton on the human body are explored through musculoskeletal modeling and simulation in OpenSim. With the hip-driven exoskeleton, the hip joint moment in swing phase decreased by 40.08%, and the total power of hip flexors decreased by 26.63%. The results suggest that this hip-driven exoskeleton could provide specific walking assistance for greatly reducing the demand of the hip muscle strength of the patients.