In comic books, it's not enough that there are suits that give mere mortals super-human strength. No, these super suits have to be so lightweight that they fit into a suitcase — or underneath ordinary clothing. Through a Defense Department-funded research project worthy of science fiction, a soft robotic exoskeleton, pulled on like a pair of pants, could one day give athletes an extra kick or soldiers the strength to lift heavier loads than their muscles alone could bear.
While an early prototype looks like an elaborate climbing harness wired to a backpack, the goal is to eventually merge the extra "muscles" with clothing. "You can imagine something like a spider web that's integrated into tightly fitting pants," Conor Walsh, a robotics researcher at Harvard University's Wyss Institute and leader of a team from Harvard and Boston University that designed and built the "exosuit," told NBC News.
This isn't the first robotic exoskeleton to walk off the drawing board and into reality. Hard metal and plastic outfits like those built by Bionics Research and Ekso Bionics and Parker Hannifin may not scream Tony Stark, but they're already beginning to give paralyzed people the ability to rise out of their wheelchairs, step through doorways and tread on a wider range of terrains.
Yet unlike those existing exoskeletons, Walsh and his team's soft exosuit will be more of an enhancer than an assistant. The soft suit is much lighter than the hard prosthetic exoskeletons, weighing just 7.5 kilograms (not including the air supply that drives the artificial "muscles"). Also, the suit relies on the existing movement of the legs as a person walks — its talent is adding a crucial nudge at the just right moment.
The suit's performance was tested by five healthy members of the Wyss lab — all male — after they trained to use it for about three days. It's confusing to react to the suit at first, but once a person adjusts to the push-and-pull of the suit, you feel the difference, Walsh said. "When you wear it, you feel like you're getting a bit of a boost. After you stop wearing it, you notice that you don't have that extra assist any more."
Getting that timing right is important for the suit to work efficiently, sort of like how finding just the right moment to push a person on a swing set can keep them going fairly efficiently for a long time, Walsh explained. This means the suit needs to be an active sensor of a person's gait as well. "If that timing is off it can actually make it harder for people to walk."
The suit would need to be custom-fit to a person's frame and gait, but that's a one-time thing, Walsh says, "If you buy a bicycle you have to adjust the handlebars and then it's set." After that, "Every time they want to wear it, they [can] pull it on like a piece of clothing."
Though applications and manufacture are years away, Walsh says the suit will see development in three main areas: in military applications, to help soldiers walk farther and carry heavier loads; as performance enhancers for athletes; and in rehabilitation medicine as an assistive technology for people who've retained the ability to walk, but find it difficult because their muscles are weakened or seen minor damage.
In July last year, Walsh won a $2.6 million dollar contract as part of DARPA's Warrior Web program for developing a suit that "helps improve physical endurance for soldiers in the field," according to a release published by the Wyss Institute at the time. This year, at the International Conference of Robotics and Automation in Germany in May, the group showed off a prototype suit for the first time, and presented the results of the first performance tests.
Michael Goldfarb, professor of mechanical engineering at Vanderbilt University, who led development of the Indego robotic exoskeleton now being manufactured by Parker Hannifin, says that the creative approach taken by Walsh and co. is just "what a field needs to move it forward," he told NBC News.
Still, he does wonder about the lifting applications that the suit might one day be used for: "Your muscles are three times as strong, but your bones aren't any stronger," he explained.
For now, Walsh's group is treating the suit as a research prototype, and figuring out how to make it more practical. For example, the "muscles" — or actuators, as roboticists like to refer to them — are powered by compressed air (you can hear the hissing in the YouTube video). The goal is to switch to an electrical, battery-operated system instead.
But Walsh believes he will wear a version of his design one day. "I honestly think that if I get to be 60 and I want to hike up Mt. Washington with [my kids], wearing something like this might allow me to do that," he said.
In addition to Conor Walsh, who is affiliated with the Wyss Institute and the Harvard School of Engineering and Applied Sciences, the team working on the exosuit includes Michael Wehner, Brendan Quinlivan, Patrick Aubin, Ernesto Martinez-Villalpando, Michael Baumann, Leia Stirling, Kenneth Holt and Robert Wood.