Abstract
This paper describes an Adaptive Automatic Steering Control System which has recently been developed by Nippon Kokan K.K. in cooperation with Yokogawa Hokushin Electric Corporation.
The purpose of the system is to optimize both the course-keeping and course-changing ability of ship's autopilots under diverse operational and environmental conditions.
The control systems for course-keeping and course-changing are distinctly different:
(1) Course-Keeping Control
An on-line parameter optimization procedure, based on the Hill-Climbing Method, is used in order to minimize the propulsion losses due to steering.
(2) Course-Changing Control
Model Reference Adaptive Control (MRAC) is used in order to improve the transient characteristics during course changes, which makes it possible to assign the desired characteristics by a reference model.
Full-scale sea trials have been carried out with this system, which show a great advantage for both economical steering ability and improved maneuverability.
