A soft, wearable device that mimics the muscles, tendons and ligaments of the lower leg could aid in the rehabilitation of patients with ankle-foot disorders such as drop foot, said Yong-Lae Park, an assistant professor of robotics at Carnegie Mellon University.

Park, working with collaborators at Harvard University, the University of Southern California, MIT and BioSensics, developed an active orthotic device using soft plastics and composite materials, instead of a rigid exoskeleton. The soft materials, combined with pneumatic artificial muscles (PAMs), lightweight sensors and advanced control software, made it possible for the robotic device to achieve natural motions in the ankle.

The researchers reported on the development in the journal Bioinspiration & Biomimetics.

Park, who did the work while a post-doctoral researcher at Harvard’s Wyss Institute for Biologically Inspired Engineering, said the same approach could be used to create rehabilitative devices for other joints of the body or even to create soft exoskeletons that increase the strength of the wearer.