Towards semi-autonomous operation of an over-actuated river ferry

Abstract

Abstract The automation of ships will in the long run enable new mobility concepts and profitable business models both for offshore and inland vessels. However, automation in shipping can already today offer significant benefits for the environment as well as for the safety of people, infrastructure and the vessel itself. To gain these advantages, sophisticated sensors, reliable propulsion systems and intelligent algorithms are required. In this context, the project AKOON is investigating the potential of the automation of a river ferry. The ferry under investigation operates on the Rhine near Mainz in Germany and is being converted to a fully automated vessel as part of the research project. This article gives an overview of the guidance, navigation and control (GNC) modules of the automation with focus on the trajectory planning and trajectory tracking modules. The trajectory planning uses hybrid-state A* to find safe and fuel-efficient routes. The subsequent trajectory tracking is achieved by a two-level approach that uses a state-space controller and an optimization-based thrust allocation to efficiently operate the over-actuated propulsion system consisting of four cycloidal propellers. Results from a high-fidelity vessel simulator based on state-of-the-art hydrodynamic simulations show that the presented approach allows the generation of collision-free reference trajectories, that can be tracked safely even in cases of model mismatches and disturbances.