Researchers from Carnegie Mellon University, Harvard University, the University of Southern California, MIT and BioSensics have developed a soft, wearable robotic device powered by pneumatic artificial muscle actuators for the rehabilitation of patients with ankle-foot disorders, such as drop foot.
Compared with a rigid exoskeleton, this active orthotic device uses soft plastics and composite materials combined with pneumatic artificial muscles (PAMs), lightweight sensors and advanced control software to achieve natural motions in the ankle.
Researchers attached the device’s artificial tendons to four PAMs, which correspond with three muscles in the foreleg and one in the back that controls ankle motion, and found the prototype was capable of generating an ankle range of 27° sagittal motion. However, according to a press release, researchers also found the soft device more difficult to control compared with an exoskeleton, requiring more sophisticated sensing to track the position of the ankle and foot and a more intelligent scheme for controlling foot motion.
The orthotic device is suitable for aiding patients with neuromuscular disorders of the foot and ankle associated with cerebral palsy, amyotrophic lateral sclerosis, multiple sclerosis or stroke.
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Disclosure: This research was sponsored by the Wyss Institute and the National Science Foundation.