The Optimal Control Of Ship Steering System

Based on the theory of ship's manoeuverability and the results of recent researches, a CARMA model for ship's manoeuvering control system is established, adopting Nomoto model with consideration of random and constant interference. The variations of ship model parameters are tracked hi real time by means of generalized-recurrence least-square method with forgetting factors hi identifying CARMA model parameters. The generalized variance performance indexes within the limit of ship's weighted deviations are set by an analysis of sailing safety and economy. The performance indexes then produce a new sailing adaptive control calculation method, which makes it possible to design an adaptive controller capable of automatic course-keeping steering and control as well, thus, further improving ship's manoeuverability, control accuracy and the adaptability of the system.To testify the effectiveness of the control strategy, a simulant study is made, in the present paper, of the adaptive system and an analysis is made of the results. A brief retrospective review of the development of autopilot is made hi terms of control theory and the author's view of its prospect is also raised.