Eco-Friendly Speed Control Algorithm Development for Autonomous Vessel Route Planning

Abstract

The upcoming autonomous vessel voyage is promising future in the maritime sector. However, so far, the contemporary route decision making technologies rely on human intervention. Therefore, this manuscript proposes the two newly developed speed algorithms: the modified fixed speed control and the wave feed forward speed control in the route decision making procedure for the autonomous vessels. These two algorithms can control the vessel's speed without human intervention in eco-friendly and economic manner. The first algorithm is the wave feed forward speed control that can predict the speed change according to wave loads and compensate it to reduce the fluctuation of speed, power, and fuel consumption. To develop this algorithm, the real time modeling of the wave added resistance and the wave real time effect on propulsion are analyzed. The efficacy of the developed wave feed forward scheme is validated using the in-house route optimization simulation program through comparisons with the results of conventional speed governor control case. The developed schemes are applied to a 173 K LNG (Liquefied Natural Gas) carrier with twin propulsion. The other proposed speed control algorithm is the modified fixed control algorithm. This algorithm improves the conventional fixed power control algorithm by adding a time marching module to satisfy the required time arrival of the voyage. The two proposed methods are analyzed in the various simulations-ideal environmental conditions and real voyage environments: The Pacific and the Atlantic cases. Based on the results, the suggested methods can reduce fuel oil consumption, gas emission, and wear and tear problem of the propulsion devise of ship. In the study, it is clearly demonstrated that the developed wave feed forward speed control and modified fixed power scheme perform much better than the conventional speed governor control case.