Wearable robot mobility helpers can be heavy and cumbersome, but they have the potential to help those who can’t move to walk again or make light work of heavy objects. For a number of years, researchers at Harvard’s Wyss Institute have been working on a soft exosuit that’s lightweight and portable, and the latest version can provide both walking and running assistance.
The project blossomed from DARPA’s Warrior Web program, which called for the development of alternatives to bulky powered exoskeletons like the Guardian XO Max. Last year, a Harvard team comprising members from the Wyss Institute for Biologically Inspired Engineering at Harvard University and the Harvard John A. Paulson School of Engineering and Applied Sciences revealed a version of a soft exosuit that could auto-adjust assistance levels on the fly.
Now the project has expanded to include researchers from the University of Nebraska Omaha, and has shortened the unit to just the hip and thighs while automatically providing assistance for both walking and running.
The team points out that due to differences in walking and running gaits, providing assistance has proven to be a challenge. But progress has been made thanks to an extension of the hip joint that’s common for both gaits.
An algorithm detects the transition between gaits and vice versa by monitoring the acceleration of the wearer’s center of mass using sensors attached to the body. Upon determining the correct gait, the mobile actuation system attached to the lower back adjusts its profile to supply the appropriate tensile force between a waist belt and thigh wraps.
The wearable weights 5 kg (11 lb), with most of that located close to a user’s center of mass which “minimizes the energetic burden and movement restriction to the wearer,” according to co-first author on the study Jinsoo Kim.
In tests on a treadmill, the metabolic costs of walking were reduced by 9.3 percent, and running by 4 percent, compared to when the testers moved without the device. Though study lead recognizes that these metabolic reductions are small, the latest development effectively demonstrates that it is possible for wearable exosuits to support more than a single activity.
“This breakthrough study coming out of the Wyss Institute’s Bioinspired Soft Robotics platform gives us a glimpse into a future where wearable robotic devices can improve the lives of the healthy, as well as serve those with injuries or in need of rehabilitation,” said Donald Ingber, M.D., Ph.D., Founding Director of the Wyss Institute.