A synergy-based lower limb exoskeleton that embodies natural human motor intelligence

A key issue in wearable robotics is the design of an exoskeleton robot with human-like motor capabilities to match the wearer's natural locomotion in daily life. It poses a challenge for an exoskeleton to replicate the sophisticated motor intelligence that enables humans to master a variety of agile motor skills. We herein propose a new design principle for lower limb exoskeletons that can transfer human motor intelligence to the robotic mechanical system and thereby endow the designed exoskeleton with natural locomotion capabilities. We first captured the synergistic characteristics among lower limb joints in human natural locomotion, and identified basic motor primitives (i.e. kinematic synergies). Then we established the mechanical design principle for exoskeletons capable of replicating the locomotor synergistic characteristics. Finally, we proposed the implementation of the kinematic synergies to ensure the compactness and lightweight of the exoskeleton. Experimental tests were conducted on a prototype exoskeleton to validate the effectiveness of the proposed design principle. The results confirmed that the proposed exoskeleton could assist users in completing a variety of locomotor tasks while exhibiting inherent characteristics of human locomotion. These findings demonstrate the potential of the design principle to advance the development of wearable exoskeletons for applications such as daily mobility assistance, post-stroke rehabilitation, and industrial load-carrying.