The future of walking aids may not come from canes or walking frames, but from robotic exoskeleton shoes.
That’s the vision of researchers at Stanford University’s Biomechatronics Laboratory who have created their first untethered exoskeleton designed to propel humans while walking. I came to Stanford for CNETvideo series to put the exoskeletons through their paces (quite literally) and see if my fast walk can be powered up, superhero style.
Patrick Slade, the postdoctoral fellow behind the exoskeleton design, has given me a lot of hope on that front.
“This is the Iron Man of the real world,” he says. “It’s basically a motorized shoe… By replacing the function of your calf with a motor, we can really boost your stride and help you walk easier and faster.”
The exoskeleton fits over your foot via a regular shoe (although one is retrofitted with sensors) attached to the calf via a carbon fiber brace and cables. As you walk, a motor behind the calf unwinds the cable attached to the shoe, allowing you to push off the ground more easily.
But the extra secret of this exoskeleton is that it learns how you walk the longer you wear it. A machine learning system built into each shoe receives input from sensors on the exoskeleton to understand how your ankle moves and when your foot makes contact with the ground. It then adjusts the motor and power to match the lift to your gait.
That machine learning system was developed with the help of “exoskeleton emulators” at the Biomechatronics Laboratory. These systems are essentially large exoskeletons permanently mounted on treadmills in the lab, allowing researchers to test different iterations of a design without physically building prototypes.
“You can think of this as a virtual reality system for your feet,” said Steve Collins, an associate professor of mechanical engineering at Stanford and head of the lab. “We program into a device that we think can help a person, put the emulator in, they feel what it would be like to walk on that device. And then, if it helps, we refine the design. If that doesn’t help. t then we give it up and try something new.”
But testing in the lab is one thing, testing in the real world is a whole different ball game. I traveled to Stanford University with Patrick Slade to test exotics. After lacing up my boots, strapping on the leg straps, and strapping the battery pack to my waist, I was ready to go.
Within just two or three steps, I could feel the motors in my legs revving and starting to lift me off the ground. I felt less like Iron Man (still no blast into space), and much more like a robot was controlling my legs.
There was no doubt that I had a spring in my step. But the problem with getting used to these exoskeletons wasn’t with the car, it was with me. My brain made it harder than I thought. Just like pulling a muscle in your leg can cause you to unconsciously change your gait as you adjust your gait to compensate, my legs and my brain didn’t know what to make of this sudden new relief. I started to walk a bit like a robot. I felt like Jack Donagh on 30 Rock when he suddenly forgets how to move like a normal person.
According to Patrick Slade, although the exoskeleton is quick to learn, it takes humans longer. Patients and subjects are usually trained in a laboratory, and their bodies and brains usually take several hours to adjust to the assistance. I was running this quickly in less than an hour.
However, I could absolutely feel the difference. And the biggest change happened when I took the shoes off. Suddenly, my legs felt like dead weight, like I’d been lifted out of a pool and gone weightless through the full force of gravity.
By testing these prototypes over the course of a day, I got a real look at how much of a difference this research can make. Slade and team hope that these types of assistive devices — high-tech wearable devices that adapt to users — can help elderly patients or those with walking difficulties achieve new levels of mobility that are fully tailored to their needs.
To see exoskeletons in action, watch this week’s episode of What’s Next at the top of this article.