Researchers from the Korea Maritime & Ocean University have developed a new method for the path-following performance of autonomous ships.
In a new study, researchers investigated the path-following performance of maritime autonomous surface ships (MASS) using a free-running computational fluid dynamics model. Their findings can help ensure safer autonomous navigation with reduced propulsion power.
An essential requirement of MASS is the ability to follow a pre-determined path at sea, considering factors such as obstacles, water depth, and ship manoeuvrability. Any deviation from this path for any reason poses serious risks like collision, contact, or grounding incidents.
Current methods for assessing the path-following performance of autonomous ships are unable to capture the complicated interactions between the hull, propeller, rudder, and external loads of ships, leading to inaccurate estimates of path-following performance.
The National Korea Maritime & Ocean University in its study applied a free-running computational fluid dynamics (CFD) model combined with the line-of-sight (LOS) guidance system, at low speeds under adverse weather conditions.
In the case of the bow and beam waves simulation, deviations decreased with an increase in propulsion power while in the case of quartering waves, there was a negligible effect of propulsion power on the deviations. Additionally, the heave and pitch responses of the ship were heavily influenced by the direction of the incident waves. In all three cases, the roll amplitudes were consistently below 1.5 degrees.
“The proposed CFD-based model can provide a valuable contribution to enhancing the safety of autonomous marine navigation. Moreover, it can also offer low-cost alternatives to model-scale free-running experiments or full-scale sea trials,” said Daejeong Kim from the Division of Navigation Convergence Studies at the National Korea Maritime & Ocean University.
