Researchers at Vanderbilt University have developed a lightweight and inexpensive ankle exoskeleton to assist those with impaired lower leg muscles or those in jobs that require a lot of running or walking. Unlike previous ankle exoskeletons, the device is small enough to be worn discreetly under clothing.

Developing assistive exoskeletal structures to aid people with limited mobility is an active area of research. However, in many cases such devices can be heavy, bulky, and unwieldy, making them difficult to use and wear. To address this, researchers at Vanderbilt have come up with a lightweight exoskeleton for the ankle.

“Our design is lightweight, low profile, quiet, uses no motor or batteries, it is low cost to manufacture, and naturally adapts to different walking speeds to assist the ankle muscles,” said Karl Zelik, a researcher involved the study.

The exoskeleton weighs slightly over one pound (1/2 Kg) and includes a friction clutch component, which is not thicker than a shoe insole and therefore fits snugly under a shoe or foot. An assistive spring helps the user to generate force while walking or running and a soft sleeve holds the exoskeleton comfortably in place against the lower leg. At a cost of less than $100 to make, the device is inexpensive, making it more accessible for a variety of users.

In a first for this type of technology, the device is low-profile and so can be worn under clothing. “We’ve shown how an unpowered ankle exoskeleton could be redesigned to fit under clothing and inside/under shoes so it more seamlessly integrates into daily life,” said Matt Yandell, another researcher involved in the study.

“The potential applications are broad, from helping aging people stay active to assisting recreational walkers, hikers or runners,” said Zelik. “It could also help reduce fatigue in occupations that involve lots of walking, such as postal and warehouse workers, and soldiers in the field.”

Conn Hastings
Conn Hastings received a PhD from the Royal College of Surgeons in Ireland for his work in drug delivery, investigating the potential of injectable hydrogels to deliver cells, drugs and nanoparticles in the treatment of cancer and cardiovascular diseases. After achieving his PhD and completing a year of postdoctoral research, Conn pursued a career in academic publishing, before becoming a full-time science writer and editor, combining his experience within the biomedical sciences with his passion for written communication.