Fuzzy Autopilot for Ships Experiencing Shallow Water Effect in Manoeuvering

Abstract A fuzzy autopilot for ship path control is proposed. Nonlinear model of a ship and a steering subsystem is used. The autopilot uses heading signal and yaw rate signal to produce a command rudder angle. The autopilot does not use lateral offset from the nominal track. Input variable fuzzyfication, fuzzy associative memory rules and output set defuzzyfication are described. The influence of the shallow water effect during larger maneuver is analyzed.