Design of a Passive Load-Bearing Exoskeleton With Reduced Joint Misalignment and Leg Interaction Forces

Load-bearing exoskeletons offer assistance in military, firefighting, and logistics fields. In such scenarios, weights are carried across uneven terrains. Therefore, an exoskeleton that efficiently transfers loads to the ground, adapts to versatile gaits, and minimally impacts leg movement is desired. This article presents a passive load-bearing exoskeleton to achieve these objectives. The passive exoskeleton operates without external power, transfers the load to the ground and redirects interaction forces from the thigh to the waist, and reduces potential impact on leg motion. A hip force-restoring mechanism and an optimized knee four-bar linkage were developed to minimize misalignment, enhancing human–machine kinematic compatibility. Experiments on five participants showed that the exoskeleton can reduce misalignment by 42.55% during load-bearing walking and 79.68% when squatting. The thigh interaction force was decreased by 55.65%, and load-transfer efficiency reached 60.10%. Compared to commercial load-bearing exoskeletons, there was a significant reduction in metabolic cost both indoors and outdoors, showing the exoskeleton's effectiveness in various terrain conditions.