A Novel Quasi-Passive Non-Anthropomorphic Lower Limb Exoskeleton for Load-Bearing

Load-bearing walking is an important requirement for defense and military, logistics and transportation. In this letter, a novel quasi-passive non-anthropomorphic lower limb exoskeleton is proposed to augment human load-bearing capacities. The exoskeleton employs a rigid leg rod that transmits loads, and this leg can be switched between stiff status and stretchable status according to the human gait phases. The length of the exoskeleton leg rod can be adjusted via a screw mechanism in the stance phase to decrease the fluctuation of load vertically. The feasibility of the developed non-anthropomorphic exoskeleton is verified by load-bearing experiments, which show that the exoskeleton with an adjustable length via the screw mechanism can reach 59.1% support-load ratio (SLR), which is higher than 48.8% SLR obtained with the non-adjustable length in the double support phase; and 42.5% SLR with an adjustable length, which is higher than 37.2% SLR obtained with the non-adjustable length in the single support phase during walk gait with 1.5 km/h speed.