Reducing Migration of Knee Exoskeletons With Dynamic Waist Strap

Abstract

Downward migration of knee exoskeletons under external forces is one major concern against their normal operations. It may be reduced by increasing the friction between exoskeletons and the human thigh. However, the effectiveness of friction control remains questionable, as the natural inverted-cone shape of the human thigh will aggravate downward migration, and the overwhelming strapping intensity will degrade the activation level of muscles. In this paper, we propose a new suspension system called the Dynamic Waist Strap. Theoretical analysis and experimental validations on multiple subjects are conducted to show its advantages over the three mainstream suspension systems commonly used for knee exoskeletons in terms of the reduction of migration, interaction torque, and maximum dip angle. This study highlights the importance of the suspension system when attaching a knee exoskeleton to the human and introduces a new dynamic interaction interface to improve the coupling from a knee exoskeleton to an individual.