IT’S enough to put a spring in your step. A soft robotic suit has helped three people recovering from a stroke to walk better.
The suit, developed by a team led by Conor Walsh at Harvard’s , is made of flexible fabric that attaches to the waist, thigh, calf and shoe. Cables fastened to the outside of the suit can contract in the same directions as muscles, helping to move the legs.
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The three people who tested the suit – one woman and two men, aged 29, 60, and 63 – could already walk, albeit with artefacts from their stroke. Using the suit, they took 11% less time between steps and walked more symmetrically. Its support could prevent injuries that arise from compensating for a weaker leg, and help people recovering from a stroke to do more of their rehabilitation at home or while out and about, rather than in the clinic.
“They’re improving pretty fast in getting things lighter and more efficient,” says , a biomechantronics researcher at the University of Twente in the Netherlands.
Walsh’s team presented the work in August at the 2015 IEEE International Conference on Rehabilitation Robotics in Singapore ().
Exoskeletons are already in use for other kinds of rehabilitation. People paralysed from the waist down can use rigid exoskeletons to take basic steps, controlling the suit either with their upper body or an EEG skull cap. Other exoskeletons are designed to help people walk while carrying heavy loads, often aimed at soldiers hefting heavy packs over long distances. A battery-powered ankle exoskeleton tested on healthy people by at the Massachusetts Institute of Technology was the first to make walking more efficient.
But all of these set-ups have drawbacks. Hard exoskeletons are much more expensive than wheelchairs, and to be practical, their prices need to decrease about tenfold, says van der Kooij. It’s also a challenge to align a rigid robot’s joints with the body’s joints, and misalignment can cause injury or stress. What’s more, exoskeletons are heavy, so if a patient falls they may not be able to get back up. The obvious visibility of the suits can also seem a source of stigma for their wearers.
Walsh’s prototype is more discreet, but still not low-profile enough. The volunteers had to be tethered to a motor on a trolley, which powered the suit. His team is planning another model in which the motor can be worn on the body. The team also wants to generate more force to boost walking efficiency.
Nevertheless, soft exoskeletons might go be better accepted than rigid models. “The soft solutions hinder natural motions less, and also tend to be more lightweight and smaller so you can wear them under your clothes,” says van der Kooij. “I think for most people that will be socially preferable to having a huge kind of Iron Man suit.”
“For most people, a soft robot suit will be socially preferable to having a huge kind of Iron Man suit”
(Image: selimaksan/Getty)
This article appeared in print under the headline “Softly-softly approach”
