Design and Characterization of an Automated Assistive Knee Brace for Leg Muscle Rehabilitation

The advances in the field of mechatronics and robotics have allowed us to create a variety of medical devices. Comparable advances are not reported in the area of rehabilitation and assistive devices. In the prior work, the authors have created an automated orthotic knee joint that provides assistance to the victims of partial paralysis. This device uses electromyography sensors to gather impulse signals and use pneumatic actuators in the form of fluidic muscles. A microcontroller is used to interpret the signals from the sensors and uses a feedback control loop to provide augmented strength and mobility to the wearer. This paper reports a couple of experiments performed to characterize the behavior of this knee brace. Firstly, the brace is operated stand-alone with the help of electromyography sensors attached to a healthy individual. The system provided reaction times from one to three seconds, which is reasonable for an assistive device. Next, the system is attached to a mannequin that mimics the behavior of a human knee. While the brace is observed to be behaving as expected, the reaction times were significantly higher than that of the natural motion of the human leg. The study provided insights about several parameters that need to be optimized before the brace is completely operational.