Model predictive control framework for green and smart tug escorting

Abstract

In this paper, we proposed a novel smart tug escorting mode to achieve energy conservation during the escorting process under the premise of safe navigation of the serviced ship. A green and smart framework is presented for energy-saving escorting. First, an escorting model is established to describe the dynamics of the tug and the relation between the tug and the serviced ship. Secondly, the reference trajectories of the tug and serviced ship are planned collaboratively according to the escorting geometric configuration. Then, the Model Predictive Control (MPC) scheme is adopted for tug trajectory tracking. An optimization problem is formulated, considering the fuel consumption characteristics of the engine. Control strategies are obtained by solving the optimization problem. Two scenarios are simulated to show the energy conservation potential of the proposed framework. In the scenario that the tug is sailing along without load, the fuel consumption can be reduced by 18.47%, while in the scenario that the tug is escorting beside the serviced ship, the fuel consumption can be reduced by 21.56%.