-
Engineers from Stanford University (USA) have developed an ankle exoskeleton capable of adapting to each person, so that they can walk faster and spend less energy.
-
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.
Los exoskeletons that help move the legs, increasing the speed of walking and reducing the energy needed, can be useful for people with mobility problems, among other applications. The benefits of these devices have been demonstrated, above all, in 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’ what adapts to each user so that it can walk faster and more efficiently on the street, in real conditions. The results of their study, published in the journal Natureshow a new approach in the design of ‘wearable’ robotic systems and their potential to be used in everyday life in the future.
The device weighs 1.2 kg per ankle and has, among other components, wearable sensors of low cost, transmission systems of forces and information, and batteries that are placed on the waist of the users, in addition to a new model of data management with artificial intelligence.
“One of the advances of our work was the development of a machine learning model that uses the data from the wearable sensors of the exoskeleton (angle of the ankle, its speed and torque applied) to determine the best assistance pattern when using our device”, the main author explains to SINC, Patrick Slade.
The model compares changes in movement between different assistance conditions to see which are the best, tests others similar to these and repeats the process several times until it finds the one that best suits the characteristics of each user’s gait. “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 assist pattern for each user
The results of this new method are not only equal in efficiency to traditional systems used in laboratories to optimize exoskeletons, but it does so four times faster. In addition, various volunteers – some equipped with ‘respirometers’ to also measure their exchange of oxygen and CO2 with each breath – successfully tested it on the university campus.
With the exoskeleton support optimized for the real world, the energy cost of walking was reduced by 17% and walking speed increased by 9% (about 0.12 meters per second more) compared to wearing normal shoes alone. This energy saving is equivalent to taking off 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 walking speed,” Slade notes, “and this is because it is incredibly 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 in hard jobs
At the moment this prototype has been evaluated with young and healthy people for safety reasons, but the authors trust that improved versions can be useful for others with difficulty walkingelderly or in physically demanding jobsalthough additional studies will be required.
“Assistive devices like this could provide greater independence to people with mobility problemslike the elderly or those with muscle disease, and we’ve already started looking at that,” says Slade, “and we can also use the same ideas to improve collaboration between humans and robots 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 shoes: it is like taking off a 9.2 kg backpack
“The main challenges we are facing now are conducting experiments with specific clinical populations to determine what will be the most effective assistance for them –he adds–. Then we have to work with Business partners to translate this technology into devices that can be bought 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 lab
Related news
In a parallel article, also published in Naturethe investigator Carlos Rodriguez of the KU Leuven University (Belgium) values this work: “The advances that are presented are significant since a relatively simple method is proposed that allows adapting the behavior of the exoskeleton to the user, obtaining information on its use on a daily basis, in instead of 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 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 available to improve our quality of life.”