Will you be wearing an exoskeleton in ten years? The tech that could change how we move | Nature
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A variety of exoskeletons are entering the consumer market, including ones sold by Hypershell, a company in Shanghai, China. Credit: Hypershell
Daniel 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.<br>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”.<br>Ferris admits he was “jumping the gun”, but his vision is getting closer to reality.<br>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.<br>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.<br>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.<br>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?<br>From replacement to assistance<br>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.<br>In the past few years, several teams have reported advances in developing devices that can support more-realistic movements. A control framework devised by researchers at the Georgia Institute of Technology in Atlanta uses an artificial-intelligence system to estimate how hips move in real time for a wide range of walking speeds, inclines and stair heights. The system enabled testers to reduce their effort while walking2. Some of the same researchers and other colleagues extended the principle to a more flexible system that allows users to switch unpredictably3 between different types of movement.<br>Roboticist Robert Gregg at the University of Michigan in Ann Arbor is taking a similar approach with knees, and is leading a US$2-million project to adapt motorized orthotic braces to reduce the forces passing through the joint. In a four-person pilot study, participants reported reduced pain while using the devices during activities such as standing up from a chair and climbing stairs.<br>Robots rise to meet the challenge of caring for old people
The latest machines use what researchers describe as task-agnostic control. Whereas previous systems replayed a preset moving pattern that was timed to one body movement, task-agnostic control estimates the effort being made by the wearer’s joint in real time, then supplies a proportion of it.<br>Conventional...