Design and Experimental Verification of a Parallel Hip Exoskeleton System for Full-Gait-Cycle Rehabilitation

Rehabilitation with exoskeletons after hip joint replacement is a tendency to achieve efficient recovery of people to rebuild their human motor functions. However, the kinematic mismatch between the kinematic and biological hip is a problem in most existing exoskeletons that can cause additional stress in the hip. To avoid secondary damage, the misalignment between the mechanical and biological hip joint of an exoskeleton must be compensated. This paper introduces a novel hip exoskeleton system based on parallel structure. The exoskeleton can inherently address the kinematic mismatch by introducing additional kinematic redundancy, while requiring no additional kinematic components and volumes. To achieve bidirectional full-gait-cycle walking assistance, a remote actuation system is designed for power delivery, and a control scheme is proposed to reject disturbances caused by gait dynamics during walking exercises. Human testing was carried out to evaluate the performance of the system. The results show that the exoskeleton has good human-machine kinematic compatibility and can achieve promising force tracking in the presence of gait dynamics.