Design and Evaluation of a Soft Assistive Lower Limb Exoskeleton

Wearable devices are fast evolving to address mobility and autonomy needs of elderly people whowould benefit from physical assistance. Recent developments in soft robotics provide importantopportunities to develop soft exoskeletons (also called exosuits) to enable both physical assistanceand improved usability and acceptance for users. The XoSoft EU project has developed a modularsoft lower limb exoskeleton to assist people with low mobility impairments. In this paper, we presentthe design of a soft modular lower limb exoskeleton to improve person’s mobility, contributing toindependence and enhancing quality of life. The novelty of this work is the integration of quasi-passive elements in a soft exoskeleton. The exoskeleton provides mechanical assistance for subjectswith low mobility impairments reducing energy requirements between 10% and 20%. Investigationof different control strategies based on gait segmentation and actuation elements is presented. A firsthip–knee unilateral prototype is described, developed, and its performance assessed on a post-strokepatient for straight walking. The study presents an analysis of the human–exoskeleton energy pat-terns by way of the task-based biological power generation. The resultant assistance, in terms ofpower, was 10.9% ±2.2% for hip actuation and 9.3% ±3.5% for knee actuation. The control strat-egy improved the gait and postural patterns by increasing joint angles and foot clearance at specificphases of the walking cycle.This work has received funding from the European Union’s Horizon 2020 framework programme forresearch and innovation under grant agreement no. 688175.Peer reviewe