Yong-Lae Park, an assistant professor of robotics at Carnegie Mellon has developed a soft-wearable orthotic device to assist sufferers of gait abnormalities with ankle-foot rehabilitation. The bio-inspired device was designed using soft plastics and composite materials to achieve more natural motions of the ankle than a conventional rigid exoskeleton.
The system replicates the muscle-tendon-ligament-skin architecture of the lower limb anatomy. At its core the soft exoskeleton uses four pneumatic artificial muscles capable of achieving 14° of dorsiflexion and 13° plantarflexion in addition to ankle inversion and eversion. These muscles are connected via wire tendons which are fixed via Velcro ligaments to a skin-like sock which covers the foot. The soft orthotic also houses an array of sensors located at the knee and ankle which measure motion, strain, and pressure. It is powered by a series of lithium ion batteries and is tethered to an air source which drives the artificial muscles that can be seen in operation in the video below.
Professor Park developed the system in collaboration with colleagues at Harvard University, the University of Southern California, MIT, and BioSensics, a company which provides wearable sensors for gait analysis and activity monitoring. While the system is still very much in the proof-of-concept stage, as it is quite bulky, Professor Park has indicated that a more discrete, wearable system is on the way.
Technical note in journal Bioinspiration and Biomimetics: Design and control of a bio-inspired soft wearable robotic device for ankle–foot rehabilitation