Low Profile Ankle Exoskeleton

A new type of ankle exoskeleton is being designed at the Vanderbilt University School of Engineering. The design is lightweight, low-profile, and cost-effective for use with the elderly and persons with lower-leg muscle strength impairments. Most notably, the design is believed to be the first ankle exoskeleton that could be comfortably worn under clothing without restricting the wearer’s motion. Best of all, it requires no batteries or electronics. A study of their design was recently published in IEEE Transacations on Neural Systems & Rehabilitation Engineering, and builds upon a widely cited ankle exoskeleton concept developed in 2015. The engineering team’s design will be presented during the 2019 Wearable Robotics Association Conference in Phoenix, Arizona.

“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,” says Karl Zelik, assistant professor of mechanical engineering at Vanderbilt University School of Engineering and senior author on the study.

From the Vanderbilt University School of Engineering article: “‘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, a mechanical engineering Ph.D. student and lead author of the study.

In a significant design advancement, the team invented an unpowered friction clutch mechanism that fits under the foot or shoe and is no thicker than a typical shoe insole. The complete device, which includes a soft shank sleeve and assistive spring, weighs just over one pound.

The unpowered ankle exoskeleton costs less than $100 to fabricate, without factoring in optimized design for manufacturing and economies of scale.”

Read more about the low-profile ankle exoskeleton at the Vanderbilt University School of Engineering.