GoKawiilDaniel Ferris says that the best exoskeletons are the ones you forget about. When the biomechanical engineer has one on, he notices little more than a slight tugging. But after removing the device, it can seem as if he is suddenly trudging uphill.
How a revolutionary technique got people with spinal-cord injuries back on their feet
Ferris has been designing wearable exoskeletons and powered prostheses for decades, and has long thought that they would soon become a part of everyday life. In 2009, he published a prediction1 that “by 2024, people will be walking down the street, in the malls, and to their homes wearing robotic exoskeletons”.
Ferris admits he was “jumping the gun”, but his vision is getting closer to reality.
At the time he made his forecast, exoskeletons were mostly being used in clinical settings to rehabilitate people after spinal-cord damage or stroke. “Exoskeletons were really targeted as: function is lost, and we need to replace this function,” says Taylor Dick, a neuromuscular biomechanist at the University of Queensland in Brisbane, Australia.
Today, researchers and companies are increasingly talking about augmentation instead: adding a fraction of the force needed for a movement. A powered brace might take some load off an arthritic knee, and robotic shorts could make an older person’s daily walk less exhausting. Other exoskeleton devices are designed for a wide range of users, including young adults hoping to go farther and faster. Last October, Nike unveiled a prototype ‘powered footwear’ system called Project Amplify, which is aimed at everyday athletes, and tourists in China can rent exoskeletons during a visit to a hilly section of the Great Wall.
For proponents of exoskeletons, this augmentation can’t come quickly enough. Many countries, including Japan, China and Italy, are rapidly ageing, and the number of people worldwide aged 60 years or older is projected to reach 2.1 billion by 2050, according to the World Health Organization.
But before exoskeletons reach the mass market, researchers need to solve several technical issues. The devices need to become smarter, lighter, cheaper and easier to fit for the vast range of people who might use them. There’s also another concern that needs to be overcome: if a machine makes it easier to walk or run, will people move more and become healthier as a result — or will their bodies become reliant on it and their muscles atrophy as a result?
From replacement to assistance
For today’s exoskeleton builders, less is more in terms of the assistance the devices offer. Older devices trended more towards the style of Iron Man’s super-strength suit, whereas newer systems estimate the forces that the wearer is producing, and supply only part of what is required. That approach preserves the wearer’s control, reduces the power the machine must deliver and can make the device less taxing when it is switched off.
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