Design and Preliminary Evaluation of a Lightweight, Cable-Driven Hip Exoskeleton for Walking Assistance

Abstract

The hip exoskeleton has demonstrated the capability of enhancing human locomotion performance during walking. However, few of them reached the ideal effect and went out of the lab due to excessive weight, lack of degree of freedom and user discomfort. In this paper, we present a cable-driven hip exoskeleton that concentrates on lightweight, comfortability and human-machine interaction. The total weight of the device is 3.15 kg excluding the real-time controller. Active cable-driven actuators and passive actuators based on torsional springs are developed to provide assistive force in the sagittal plane, and allow the hip to move freely in the coronal plane. We proposed a hierarchical controller that calculates the motor current command based on sensory information and user instruction, and validated the usability and effectiveness of the exoskeleton through a series of evaluation experiments. The results showed the exoskeleton can provide 14 % of energy supply per step on average during walking. Our work may provide a possible solution for the future lightweight, high-performance, and humanized hip exoskeleton.