A holistic hydrodynamic modeling approach for ship motion prediction and berthing strategy assessment

Autonomous berthing and unberthing of ships represent the final and critical stage of maritime navigation safety. While previous studies based on simplified models achieve acceptable control, they fall short in capturing precise close-range ship motions. This study develops a hydrodynamic ship motion model combining a three-dimensional Rankine panel method with a three-degree-of-freedom MMG framework. The model consists of two modules: seakeeping and maneuvering. The seakeeping module, simulating heave, pitch, and roll for Wigley III and KVLCC2 hulls, is validated against experimental data. The maneuvering module, covering surge, sway, and yaw, is verified through turning circle and zigzag tests, demonstrating accurate nonlinear behavior capture. After validation, both modules are integrated to simulate berthing motions using an adaptive PID controller. Three berthing strategies are compared based on accuracy, rudder usage, and trajectory tracking. Results show all methods achieve berthing success under different sea states, but differ in control smoothness, space requirements, and heading stability. This study provides a reference for enhancing the safety of autonomous ship berthing and unberthing operations.