A Lower Limb Exoskeleton With Rigid and Soft Structure for Loaded Walking Assistance

The loaded walking ability of people can be enhanced by lower limb exoskeleton. How to avoid lower limb joint injuries while improving walking efficiency is a major challenge for loaded walking assistance. Inspired by the muscle-skeleton working mechanism of human, we proposed a lower limb exoskeleton with rigid and soft structure for active hip extension assistance and passive load transfer assistance. Its motion flexibility, load transfer ability and metabolic cost were investigated. Five motions including jumping jack, sit down, crouch, across obstacle, and forward lunge were realized by the wearer. Under the conditions of quiet standing and dynamic walking, the percentages indicating the degree of load transfer to the ground reached up to 88% and 67%, respectively. Compared to the condition of no exoskeleton, the net metabolic reductions of 20kg-loaded walking in three experimental setups, namely, active-passive assistance on, active exosuit assistance only, and active assistance off-passive assistance on, achieved 12.8%, 8.5% and 3.7%, individually. The results demonstrate that our rigid-soft lower limb exoskeleton presents outperformance in loaded walking assistance.