Exosuits—wearable robotic technologies that enhance our physical abilities—are slowly but steadily leaving the world of comic books and becoming a practical reality. This week, scientists introduced an exosuit that seems to reach a new milestone, helping users both walk and run with less effort.
The exosuit is the result of a collaboration between researchers from Harvard University’s Wyss Institute for Biologically Inspired Engineering; the University of Nebraska, Omaha; and Chung-Ang University in Seoul, South Korea. Perhaps more accurately described as a pair of exoshorts, the device is lightweight, fully portable, and mostly made out of a flexible material (except for the battery and motor unit). It works by using motors to pull cables that help extend the hips in a naturalistic and ideally optimum way as we move our legs, which should then reduce the amount of energy our bodies expend in order to move.
Previous exosuits could already reduce the energy costs of walking, according to Philippe Malcolm, a biomechanics expert at the University of Nebraska Omaha and senior researcher on the project. Newer, soft exosuits have been able to do this without feeling rigid and restricting range of movement. But there’s been less luck in creating portable technology that enhances a person’s ability to run, which relies on different joint and bodily movements than walking. And though a typical human can easily transition from walking to running at a moment’s notice, the same hasn’t been true for exosuits.
“In order to be able to assist not only running or walking, we needed a system,” Malcolm told Gizmodo by phone. To get over this hurdle, the team created an algorithm that detects whether the person is running or walking. Depending on the movement, it switches to the needed “force profile” for the exosuit to do its job.
A closer look at the exosuit. (Image: J. Kim, et al/Science)
Once they created their prototype, they tested it out with healthy human volunteers across different walking and running scenarios, including on a treadmill or while walking uphill. During these trials, they measured how much energy the volunteers were spending by tracking how much oxygen they needed to breathe. The results of these experiments, published Thursday in Science, are modest but impressive.
“So we found a 9 per cent reduction in the energy consumption during walking and a 4 per cent reduction during running,” Malcolm said. “There’s been higher reductions by other devices that assist only with walking, or only with running. But these are statistically significant [reductions]. And they’re within an order of magnitude where performance improvements could be expected.”
The reductions could amount to having 17 or 12 pounds taken off your waist while walking or running, respectively. But there needs to be more research done to actually show that the exosuit can help the average person run longer or faster. And there’s still ample room for improvement with the current design. For instance, though the device now weighs 11 pounds, the team is working on a system that would weigh only 6 pounds.
While the exoshorts do require some training to use, they aren’t terribly complicated.
“We tested the device with healthy people who already trained for multiple sessions with the actual suit, so you do need a certain time to adapt and learn how to benefit from the system,” Malcolm noted. “[But] there’s no specific instructions. You just put it all in and walk and run some time with it.”
For the time being, this research is a glimpse into the future of these devices, which could be modified for different purposes and functions depending on the situation. Exosuits with back support could help people better carry heavy loads with a lower risk of injury, Malcolm said, while others could help people with disabilities better rehabilitate or navigate on their own.
And to really get into the sci-fi realm, you could combine exosuits with another emerging technology: implants that allow the brain to communicate with and operate devices just like they were another limb. That sort of combination could one day enable the creation of “implantable neuroprostheses that can influence or assist human movement,” wrote José L. Pons, a biomechanical engineer and head of the Shirley Ryan AbilityLab in Chicago, in an accompanying editorial in the journal Science.
That’s not to say these suits aren’t having any real-world impact already.
This summer, the Boston company ReWalk Robotics began selling a soft exosuit system to physical rehabilitation clinics, based on some of the technology developed by the Harvard team. The ReStore Exo-Suit, as it’s called, was cleared as a medical device in June by the US Food and Drug Administration to help with the physical therapy of people with lower limb disability caused by stroke. The suit is mostly focused on the ankles, rather than the hip, but uses the same basic principle to assist people as they walk.
Featured image: Wyss Institute at Harvard University