A Novel Lower Limb Rehabilitation Exoskeleton Combined with Wheelchair.

To help people with lower limb weakness or disability rehabilitation, this paper develops a novel system of lower limb rehabilitation exoskeleton combined with wheelchair. The lower limb exoskeleton is set with 6 degrees of freedom including hip joints, knee joints and ankle joints on the basis of human anatomy. The range of rotation angle and torque of each degree of freedom are determined according to human gait analysis. Based on these analyses, we designed the hip, knee and ankle joint structures. To make the exoskeleton combined with wheelchair which was designed according to the Chinese standard of electric powered wheelchair, we designed an integrated mechanism of wheelchair and exoskeleton. Based on the integrated mechanism, a posture transformation mechanism to assist patients change between standing and sitting posture was designed. Embedded control system was established to control the whole system to do posture transformation and gait training. Taking into account the lower limb weakness or disability, we chose passive target tracking control. Finally, we simulated the gait training and posture transformation, which verified that the system could stably perform transformation and walking gait process, and it could effectively track the predetermined trajectory during gait training.