Development of Gait Rehabilitation Robot to Promote Voluntary Movements for Normal Walking

This paper proposes a lower limb rehabilitation robot for normal walking in post-stroke hemiplegic patients. Ergometers are generally used for lower limb rehabilitation, but their use has depended on the experience of physiotherapists. Therefore, this paper proposes a new rehabilitation robot based on an ergometer that guides the patient's voluntary muscle activity and helps the patient learn how to use the muscles required for normal gait. The key ideas of this paper are twofold. The first is to design an appropriate external force (assist force/load) to be applied to the pedals during the pedaling motion, so that the patient can effectively train the muscles commonly used during normal walking. The external force design considers the human characteristic of multiple muscles working in coordination and uses muscle synergy, which indicates the degree of coordination, as the evaluation axis. Second, in order to effectively train the paralyzed limb, the pedals of the ergometer have independent left and right mechanisms. The left and right pedals are synchronized by master-slave control, with the paralyzed limb side acting as master. This encourages the patient to move the paralyzed limb spontaneously. The proposed method described above has been implemented in our prototype robot and its effectiveness confirmed in experiments with post-stroke hemiplegic patients as subjects.