Development of control model for intelligently controllable ankle-foot orthosis

We have developed an intelligently controllable ankle-foot orthosis (i-AFO). In this paper, we formulated a new control method for the i-AFO. In the method the sensor system of the i-AFO estimates walking speed of user and decide optimal drop speed of foot at the duration between initial contact and foot flat. We conducted the pretest for eight healthy subjects to make a control rule for the drop speed. Then we conducted the modeling test for one patient to make an estimation rule for walking speed. Finally we conducted the evaluation test for the proposed method. Despite the walking speed estimation show errors, the i-AFO successfully controlled the foot motion depending on the gait states.