A GLOBALLY STABLE ADAPTIVE SHIP AUTOPILOT WITH WAVE FILTER USING ONLYYAW ANGLE MEASUREMENTS

A stable minimum phase transfer function from rudder angle to yaw angl e is used to design a globally stable adaptive ship autopilot. First-o rder wave disturbances in yaw are filtered by applying a notch filter. Integral action is introduced by using a reference model technique. G lobal stability is proven for the total system which include the yaw r ate observer, the parameter update law, the feedback controller, the n otch filter and the integral part of the controller. The simulation re sults showed that the performance is excellent, even with no a priori knowledge of the ship parameters.