Analysis, design and preliminary evaluation of an anthropometric self-stabilization passive exoskeleton for enhancing the ability of walking with loads

This paper introduces the analysis, design and preliminary evaluation of an anthropometric self-stabilization passive exoskeleton (ASPE) with elastic band to increase the load transmission efficiency and protect and strengthen the human body during loaded walking. Firstly, we analyze the working principle of passive exoskeleton, and propose an efficient method of reducing the degrees of freedom in exoskeleton relatively, which contributes to a self-stabilization mechanism for balancing the back torque causing by the loaded backpack and assisting human hip flexion. The design of the ASPE is then introduced in detail. The novelty of the ASPE is that the human–machine interaction forces are significantly reduced by integrating the elastic band into the exoskeleton hip joint and converting load gravity into the elastic potential energy of elastic band to assist hip joint flexion. Furthermore, we analyze the dynamic modeling of the ASPE to preliminarily calculate the transmission efficiency regarding the ratio of plantar pressure of the ASPE to load gravity. Besides, we conduct the experiment of human wearing the ASPE to evaluate the performance of the ASPE regarding the ratio of the difference of human plantar pressure with and without the ASPE to load gravity. The results show that the ASPE can effectively transfer load gravity to the ground and maintain the human natural movement. The ratio of the plantar pressure of the ASPE to load gravity is more than 70% in the simulation, and when the walking speed is 4 km/h, the ASPE reduce the human plantar pressure of 68.9% compared to without wearing the ASPE during human walking with load. The results provide evidence for the efficient transmission of the newly designed ASPE during walking with loads. The application of the ASPE have benefits for subjects walking with loads, such as soldiers, to decrease their injuries and strengthen their ability.