A study on ship's autopilot system for a small boat

This paper describes dynamics analysis of a small training boat and the application of a gain map PID controller to the autopilot of the vessel. After upgrading the autopilot of the Sazanami, an actual small training boat, in order to identify the boat model, zigzag maneuver trials were performed at various speeds. It was found that the Nomoto gain and time constant changed considerably with the vessel's speed. Based on this analysis, an improved autopilot system that utilizes a gain map PID controller to compensate for vessel maneuverability changes was designed. From the results of various control simulations, we determined that the proposed system offered significant performance improvements over the vessel's conventional autopilot.