Design of a multi-resiliency exoskeleton and its physiologic cost evaluation in uphill walking and stair climbing locomotion

Background In recent years, as the large own weight of active exoskeleton brings some difficulty to energy-sustainable, studies have shown that passive lower extremity exoskeletons can also reduce the energy consumption of human locomotion, but the energy saving is still relatively small compared with the total consumption. Methods A passive lower limb exoskeleton named Multi-Resiliency was described, and design parameters were estimated based on inverse dynamics. Furthermore, a series of experiments was designed for assessing the assisting effect of the exoskeleton in uphill walking and upstairs activities. Results In the inverse dynamics analysis, the spring release angle θ max was confirmed to be 45° for increasing assist performance of the exoskeleton. In the exoskeleton wearing experiments, the energy expenditure of subjects were decreased by 14.3% in uphill walking test and 16.0% in stair climbing test respectively. Conclusion The results show that the design of Multi-Resiliency exoskeleton is reasonable and it may effectively improve walking efficiency during uphill walking and stair climbing activities.