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Engineers from Stanford University (USA) have developed an ankle exoskeleton capable of adapting to each person, in such a way that they can walk faster and expend less energy.
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The prototype has been successfully tested in real conditions, on the street, and represents a new step towards future assisted walking devices that can be used by people with mobility problems.
The exoskeletons that help move the legs, increasing gait speed and reducing the energy required, may be useful for people with mobility problems, among other applications. The benefits of these devices have been demonstrated, above all, within laboratories with treadmills, but not in real conditions, where the speed and duration of the walk are variable.
Now, bioengineers from the stanford university in California (USA) have manufactured a exoskeletal ‘boot’ que adapts to each user so that he can walk faster and more correctly on the street, in real conditions. The results of their study, which they publish in the journal Natureshow a new approach in the design of ‘wearable’ robotic systems and their potential for future use in everyday life.
The device weighs 1.2 kg per ankle and has, among other components, wearable sensors low-cost, force and information transmission systems, and batteries that are placed on the users’ waists, as well as an innovative data management model with artificial intelligence.
“One of the advances of our work was the development of a machine learning model which uses the wearable data from the exoskeleton sensors (ankle angle, its speed and applied torque) to determine the best assistance pattern when using our device», the lead author explains to SINC, patrick slade.
The model compares movement changes between different assistance conditions to see that excellent are the best, it tests others similar to these and repeats the process several times until it finds the one that best suits the gait characteristics of each user. “This approach slowly converges on what the device considers to be the best attendance pattern for each person”, says the engineer.
A machine learning model uses data from the exoskeleton’s wearable sensors to determine the best assistance pattern for each user
The results of this new method not only equal in efficiency to that of traditional systems used in laboratories to optimize exoskeletons, but also four times faster. In addition, various volunteers – some with ‘respirameters’ to also measure their oxygen and CO2 exchange with each breath – successfully tested it equipped on the university campus.
with the exoskeleton support optimized for the real world, the energy cost of walking was reduced by 17% and gait speed increased by 9% (about 0.12 meters per second more) compared to wearing normal shoes alone. This energy saving is equivalent to getting rid of a 9.2 kg backpack.
“Until now, no exoskeleton has shown real-world benefits in terms of reducing the energy required to walk or increasing gait speed,” Slade notes, “and this is because it is extremely difficult to help humans to walk due to our highly evolved and specialized muscular, tendon, and skeletal design, which makes movement very efficient.”
Help the elderly and hard jobs
At the moment this prototype has been evaluated with young and healthy people for safety reasons, but the authors are confident that improved versions may be useful for others with walking difficultiesold age or potentially demanding jobsalthough additional studies will continue.
“Assistive devices like this can provide greater independence for people with mobility problemssuch as the elderly or with muscular diseases, and we have already started to study it”, says Slade, “and we can also use the same ideas to improve the human-robot collaboration in a wide range of tasks (factory work, assisted living, surgery, etc.), using data-driven models that optimize robotic responses to human movements.”
With this device, it has been possible to reduce the energy cost of walking by 17% and increase its speed by 9% compared to wearing only normal footwear: it is like taking off a 9.2 kg backpack
“The main challenges we are facing now are to carry out experiments with specific clinical populations to determine what will be the most effective assistance for them,” he adds. Then we will have to work with Business partners to translate this technology into devices that can be purchased and used on a daily basis. Although our research prototype is functional, it needs a lot of engineering work to become a robust product in everyday life.”
Exit out of the laboratory
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in a parallel articlealso published in Naturethe investigator carlos rodriguez from the KU Leuven University (Belgium) values this work: «The advances that are presented are significant since a relatively simple method is proposed that allows the behavior of the exoskeleton to be adapted to the user, obtaining information on its use on a day-to-day basis, in rather than being confined to complicated methods in highly specialized laboratories.
“The nature of this method – he concludes – allows the device to adapt more naturally and quickly to the differences in the gait present in each one of us. This decrease in complexity is accompanied by the promise of bringing this technology ever closer to end users and a little closer to a future where bionic devices They are available to improve our quality of life.”