2000 Volume 13 Issue 12 Pages 560-565
An ankle orthosis is prescribed for the persons who have the movement disorders caused by the paralyzed ankle. The most important purpose of the ankle orthosis is to support the gait by keeping the toe clearance. However, the conventional ankle orthosis with fixed joint restricts the motion of ankle because the ankle orthosis has no actuators. Therefore, the flexible and powered ankle orthosis is required to realize smooth walking. In this paper, a powered ankle orthosis with a progressive wave type ultrasonic motor (PUM) is proposed. To achieve smooth walking, a fuzzy reference generator and a fuzzy feedforward controller are introduced. The objective of the fuzzy reference generator is to estimate the appropriate ankle motion, which is obtained from the walking experiments for a person without handicap.The fuzzy feedforward controller is used to improve the tracking performance of the ankle positioning system. The effectiveness of the proposed ankle orthosis is demonstrated by experiments.