Alan Asbeck, an assistant professor in the Department of Mechanical Engineering, has been awarded a National Science Foundation Faculty Early Career Development (CAREER) award to create a new type of lower-body exoskeleton to augment walking. With the exoskeleton, his team will study the way people walk and adapt to exoskeleton assistance.
Exoskeletons can enable almost superhero-like capabilities for their users, or they can help them restore lost abilities. The devices use actuators or springs to add strength for a user or to help them move, augmenting motions such as lifting or walking. Asbeck has been working in this area for the better part of a decade, creating assistive robotics for projects such as an enhanced lifting support exosuit in partnership with Lowe’s home improvement stores.
For the CAREER award, Asbeck is developing a new approach for exoskeletons to aid walking. Typically, lower-body exoskeletons consist of rigid structures strapped to the legs, with an actuator creating torques at each joint. Exoskeletons need to produce the correct force to always complement motion or else they will hinder instead of help movement. In the worst case, incorrect or unanticipated exoskeleton behavior could cause the user to stumble or fall.
Asbeck’s project will depart from the traditional approach of strapping structures to a subject’s legs, choosing instead to create a structure that allows a user’s legs to remain mostly free. Asbeck’s exoskeleton will push upward between a person’s feet and waist, leaving the individual joints in the leg unconstrained so they can function normally. With this architecture, the exoskeleton only needs to produce forces similar to those between the feet and the ground — a much simpler problem than determining the best torque for each individual joint. As an additional measure of simplicity, the device will do this with only a single motor on each leg.
“This new exoskeleton architecture holds promise for helping people walk who would have difficulty doing so otherwise, or enabling people to walk with greater endurance,” said Asbeck. “It’s a lot simpler than most exoskeletons and will allow people to move naturally, paving the way for new applications and widespread use.”
Asbeck’s team will conduct a variety of experiments with the exoskeleton to understand how people walk, how people adapt to exoskeletal forces, and how to reduce the likelihood of falls during walking.
The team will use the exoskeleton’s built-in sensors to detect the user’s movement, adapt the exoskeleton forces to provide the best assistance, and measure the user’s response. The experiments will map the dynamics of balance and movement that occur during walking, including factors such as changes in gait when ascending and descending hills.
Understanding how the body responds to forces at its center will lead to general principles for how lower-body exoskeletons affect the body’s stability and future motion. This in turn will allow the team to determine how to decrease the likelihood of a fall.
“I’m really hopeful that through this project, we can learn how to make exoskeletons that work well in all situations and for people with all different amounts of mobility,” said Asbeck.
In addition to conducting research and building a new exoskeleton, the team will initiate educational outreach, including maintaining public video channels to discuss exoskeletons and robotics and engaging pre-college students with workshops on biomechanics and exoskeleton control in collaboration with the Center for the Enhancement of Engineering Diversity.