A self-learning exoskeleton boot that allows you to walk faster while consuming less energy can keep the elderly and people with disabilities mobile.
Existing exoskeletons have never made the leap to real-world application because they have to be very precisely matched to the wearer’s gait. That takes a lot of time and expertise. If they are not adjusted properly, the improvement is minimal or can even make walking difficult.
“Unlike what you see in comic books and superhero movies, exoskeletons are really tricky to make,” says mechanical engineer Steve Collins from Stanford University in California. Customizing an exoskeleton boot for an individual is a lengthy task. The wearer has to come to the lab for five days in a row to walk on a treadmill for two hours. In addition, he or she must wear an uncomfortable respirator and sensors to measure the air inhaled and exhaled, in order to track the energy consumption by the body.
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Just walk out
The researchers have now designed a computer model that takes over some of this work. Based on data from 3,600 previous lab tests, the model figured out how energy consumption can be approximated by just looking at the measurements from the exoskeleton’s sensors. This means that the wearer can simply start walking with the exoskeleton boot. The boot can be further adjusted while walking. This no longer has to be done on a treadmill in a laboratory.
The method achieved more than 95 percent of the efficiency of the laboratory approach, in a quarter of the time and without the need for expensive specialized breathing equipment. Collins says this research could finally make exoskeletons practical and affordable.
9.2 kilo backpack
The exoskeleton boots used in the trials are made of aluminum and carbon fiber. They have a motor that pulls on a lever to help the ankle rotate, and to push off harder with the toes.
The team found that when used outside of a lab, the device resulted in a 9 percent increase in walking speed. In natural walking, the boots reduced energy consumption by 17 percent. The researchers calculate that this energy saving is roughly equivalent to removing a 9.2 kilogram backpack.
“When I started this as a new professor 12 years ago, no one had ever designed a device that makes walking easier for someone,” Collins says. “Everything we tried just made it harder. But I think we’re finally here. I think in the coming years we will see products that actually improve people’s lives, based on this research.’
Constantly optimized
Collins says that the approach approach is not only faster and cheaper, but also constantly updated. Laboratory testing may provide a more accurate solution, but it may become less suitable over time. “These things can be continuously optimized for your needs as you walk,” he says. “Your body changes slowly, muscles adapt, your habits change, you gain or lose weight. The optimal help will therefore also change slowly over time.’