Quasi Real-Time Optimal Control Scheme for Automatic Berthing

In this paper, a quasi real-time method applicable to minimum-time approaching control for automatic berthing is proposed. The proposed system is composed of a multiple shooting algorithm based optimal berthing solution generator and a nonlinear model predictive controller for tracking to the optimal trajectory. There are many researches for solving non-linear optimal control problem, but practically all the algorithms take long computational time to obtain the optimal solution compared with the controlling time. The multiple shooting algorithm can generates the approximate optimal solution considering the wind disturbance at the start point of the berthing, in a few minutes. It is about the same time for minimum-time berthing. From this point of view, the term “quasi real-time” is used in our paper title.