Abstract
Ankle Foot Orthosis (AFO) are orthotic devices to support movements of ankles of disabled people, for example hemiplegia, cerebral palsy, neuromuscular disease, etc. In our research, we have developed a passive controllable AFO (Intelligently Controllable Ankle Foot Orthosis: i-AFO) which can control its ankle torque by using a Compact Magneto-Rheological Fluid Brake (CMRFB), for improvement of the walking function of the handicapped person. The brake has a simple structure and rapid response. Until now, we have developed the CMRFB and 2nd prototype i-AFO, and evaluated their function. Consequently, the gait had been improve, so the joint movement was smooth which close to normal gait. In this paper, we describe newly developed i-AFO, 3rd prototype. This device was small and lightened to use more compact CMRFB and spring unit, and we used accelerometer and potentiometer for judgment of walking states. Additionally, velocity controller works in initial stance phase to maintain stable gaits even if the walking speed changes. We conducted validation test of new device and controller for a Guillain barre syndrome patient. According to experimental results, velocity of ankle planter flexion in the initial contact phase was an important factor for good gaits, and we could control it with the 3rd i-AFO.
