Development of a controller for autonomous berthing and unberthing of intelligent ships with large-angle attitude maneuvering based on Lyapunov method

To address strong environmental disturbances, high-precision attitude control, complex trajectory constraints, and energy-saving demands in autonomous berthing/unberthing of green intelligent ships, this paper proposes an integrated trajectory planning and robust attitude control framework for a 5000-ton inland cargo ship on the Xijiang River mainline (Pinglu Canal, China). A three-degree-of-freedom attitude dynamics model and quaternion kinematics model are established. A Lyapunov-based large-angle attitude maneuver controller with time-varying gains and sliding-mode robust terms achieves high-precision stabilization of roll, pitch, and yaw. Meanwhile, SLAM mapping, multi-point navigation, visual recognition, and dynamic obstacle avoidance generate safe, smooth, energy-optimal berthing/unberthing trajectories. In a 50-second simulation under strong disturbances, the controller effectively suppresses wind, current, and wave perturbations; roll, pitch, and yaw stabilize in approximately 10, 10, and 15 seconds, respectively. Control energy consumption is significantly reduced compared with traditional methods, providing theoretical and technical support for engineering realization.