In order to one day help people with limited mobility, scientists at Stanford University have been working hard to develop an ankle exoskeleton. The group has just launched its first lacing-free version for use outside of their labs, with the ability to adjust assist levels on the fly, providing a maximum assist similar to taking off a 30-pound (13-kilogram) backpack.
The exoskeleton is designed to provide power at the ankle joint, and in research published last year, the team showed a version of the device that can increase the wearer's walking speed by about 40 percent. There is also an early version designed for runners that can increase speed by 10%.
These early iterations of ankle exoskeletons described above were experimental simulators with lots of wires, external motors, etc., and by connecting subjects to these simulators, researchers were able to collect movement data and quickly test and fine-tune the system, to provide the optimum level of assist based on gait and energy expenditure. However, these exoskeletons have significant limitations for real-world use.
Stanford's newest exoskeleton is an electric boot that applies torque at the ankle to provide a boost to the user's calf. Wearable sensors are built into the boots to monitor movement, using machine learning algorithms to adjust the level of assistance based on how a person walks.
The exoskeleton takes about an hour of walking to adapt to the user, and once adopted, it saves the user energy and increases speed, the team says, equivalent to putting down a 30-pound (13-kilogram) backpack.
Team leader Steve Collins said, "The assistance provided by the exoskeleton enables people to walk 9% faster and consume 17% less energy per distance than walking with normal shoes. These are The largest improvement in walking speed and energy expended of any exoskeleton to date, in direct comparison on a treadmill, our exoskeleton provided about twice the force reduction of previous devices."
The team says the exoskeleton is the first of its kind and believes their goal of helping people with mobility impairments is getting closer. They now plan to test it on older adults and people with disabilities and are also working on a version that improves balance and joint pain.
The research was published in the journal Nature, and the exoskeleton can be seen in action in the video below:
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