Ship Motion Control Using Multiple Algorithms

Abstract

Design and implementation of an autopilot for ships using multiple control strategies are discussed in this paper. Both course-keeping and track-keeping problems are involved, the course-keeping controller is the essential part of the track-keeping project, and the track-keeping controller is in fact a heading error calculator and transmitter. A self tuning regulator (STR) of the generalized minimum variance (GMV) type is taken as the principal controller, to which an integral controller (I) and a linear quadratic gaussian controller (LQG) are superposed to improve the performance of ship motion control and to enhance the energy saving outcomes. When the heading error exceeds a certain threshold a PlO controller or a knowledge-based multi-mode controller (MC), depending on the control is in course-keeping or track-keeping mode, will take over the heading control to overcome the severe environment disturbances or to speed up the track-following processes. Laboratory simulations and full scale sea trials have been performed, the main results are briefly reported.