Grad Seminar: Improving Interaction Between a Human and Lower-limb Exoskeleton with a Novel Protocol and Optimal Control for Older Adults

Abstract

With the global geriatric population expected to reach 1.5 billion by 2050, there has been growing interest to tackle age-associated movement impairments by developing assistive technologies. Rehabilitative lower-limb exoskeletons have been primarily developed for people with spinal cord injuries. Since the needs of older adults are different than those of individuals with spinal cord injuries, the existing exoskeletons must undergo further modifications to be appropriate for the elderly. This thesis covers two approaches taken to improve human-exoskeleton interaction for geriatric users.

The first approach is to develop a novel protocol to teach first-time exoskeleton users how to move with the device. A pre-test involving two graduate students who had no prior exoskeleton experience suggests that moving with the device for the first time may be intimidating. Moreover, there are little-to-no instructions provided on how to move with it, nor is there research done in this direction so far. To test the usefulness of the developed protocol, a preliminary study is conducted with IIT’s TWIN exoskeleton. Due to COVID-19 restrictions, only healthy, able-bodied lab members could be invited. With one group receiving the tutorial and the other group having no training, the results are presented and compared.

The second approach is to analyze and generate crutch-less sit-to-stand trajectories using optimal control. To first better understand the kinematics and forces of the movement involving a human-exoskeleton system, a healthy young subject is recruited for their ability to perform crutch-less sit-to-stand wearing TWIN with motors disengaged. Motion capture and force plate data are collected. One of the crutch-less cases is then treated as reference data to perform motion analysis using optimal control, allowing us to determine the underlying joint torques exerted to perform the motion successfully. Another optimal control problem is also constructed for motion synthesis, and the results of the optimal and feasible solutions are compared.

Presenter

Jan Lau, MASc candidate in Systems Design Engineering 

Attending this seminar will count towards the graduate student seminar attendance milestone!