Impact Analysis on Human Body of Falling Events in Human-Exoskeleton System

Powered lower extremity exoskeletons (LEE) can support and ambulate individuals in an upright posture, and meanwhile bring rehabilitative benefits. However, guaranteeing the safety of human-exoskeleton system is still a big challenge. The type and extent of probable risks of these devices have not yet been understood. Falls can result in serious injuries for LEE users and awful consequences. In this paper, we focus on the process of human-exoskeleton system falling and assess the injury of human. Herein, impacts of falling events were assessed and analyzed based on finite element method in the current study. In order to collect kinematics of the human-exoskeleton system for simulated impact analysis, an experiment platform consisting of an air bend and a ceiling rail was designed. Volunteers individually or wearing exoskeleton were asked to lean body in different directions (e.g. forward, side and backward) until they inevitably fell. The results of the experiment and simulation indicated that the main parts injured were head, thorax, spine, arm and pelvis when human-exoskeleton system fell. The maximum impact velocity of head can be 6.5 m/s, if no buffer actions were taken, and that can cause traumatic brain injury (TBI). No fractures occurred in other parts, but local squeezing and bruising could be found in the simulation. It is anticipated that the study of human-exoskeleton falling event will be useful in making safety regulations and safety exoskeleton designing.