Rudder Roll Stabilization controller design based on an adaptive criterion

At the Control Laboratory of the Electrical Engineering Department of Delft University of Technology much research has been carried out over the last two decades in the field of ship control systems, with the main emphasis on automatic steering of ships. At the moment the research is concentrated on the design of a Rudder Roll Stabilization, RRS, autopilot. This autopilot uses the rudder not only for course keeping but also for roll stabilization, where mostly stabilizing fins have been used up to now. The limitations posed by the ship´s rudder prevent ordinary use of the Linear Optimal Control Theory to design a suitable controller. Furthermore, it is in general difficult to define a proper criterion. This paper reports the simulation results of an adaptation mechanism which circumvents these problems. By taking into account the knowledge of the non-linearities and some measurement data it is possible to design a controller which yields satisfactory results under all relevant conditions.