The Research And Design Of The Ship Course-control Autopilot

The autopilot that used for ship controls is essentially important equipment in shipping maneuvering. As the increasing need of safety and transportation, the requirement for the autopilot gets greater and greater. In our country, ships mount the PID autopilot broadly, which has course control function. But track control is necessary as far as longtime navigation is concerned, for it can cut down the working intensity of seamen, improve the security. Considering ship control system situation and economy factor in our country now, an indirect track control method based on expert system is brought forward.The ship model is the foundation in the study on autopilots of ships. A ship dynamical model is proposed in the dissertation. The wind, current and sea wave disturbances can produce strong influence on ship sailing. Therefore, the wind, current and sea wave disturbances are modeled also.Track control is the key in the dissertation. After study basal principle, track control types, track arithmetic, an indirect track control method based on expert system is brought forward. In this method, during the track-keeping period, the course modification is calculated by means of expert control. Then the track control of ship is executed by means of the course controller. During the track-changing period, the distance of turning is calculated by means of the turning angle. When the distance between the ship and the turning point is less than the turning distance, the ship changes course to the next turning point by means of expert controller used in the track-changing period.The indirect track control isn't departed from course control. Based on traditional PID controller, a neural PID controller is brought forward. Emulate proved its performance is stable, the function is adaptive, and the logical frame is simple, it has potential in ship control.