An autopilot for ships designed with fuzzy sets

An autopilot for ships designed with the aid of fuzzy sets is investigated. For this design the steering behaviour of a human controller is translated into a fuzzy mathematical model. The complexity of this model requires a digital computer for implementation of the autopilot. The steering problem is split up into two regions with different control algorithms, a manoeuvring or course-changing mode and a course-keeping mode. Fuzzy sets are used also in the formulation of a fuzzy performance index that is based on human appreciation of the steering. The results are tested on a simulator, and a comparison is made between the fuzzy and a conventional PID controller which is most commonly used in autopilots.