Study on a new and effective fuzzy PID ship autopilot

Ship autopilots are usually designed based on Proportional Differential (PD) and Proportional Integrate Differential (PID) controllers because of their simplicity, reliability, and ease of construction. However, their performance in various environmental conditions is not as good as desired. This disadvantage can be overcome by adjusting works or constructing adaptive controllers, although these methods are complex and not easy. This article presents a new method for constructing a ship autopilot based on the combination of fuzzy logic control (FLC) and linear control theory (PID control). The new ship autopilot has the advantages of both the PID and FLC control methodologies: ease of construction, and optimal control laws can be established based on ship master knowledge. Therefore, the new ship autopilot can be well adapted with parameter variations and strong environment effects. Simulation using MATLAB software for a ship with real parameters showed high effectiveness of the fuzzy PID autopilot in course-keeping and course-changing maneuvers in comparison with the ordinary PID ship autopilots.This work was presented, in part, at the 8th International Symposium on Artificial Life and Robotics, Oita, Japan, January 24–26, 2003