Development and experimental validation of an autonomous USV berthing system with transition logic for multiple berthing maneuver strategies

Autonomous berthing is a fundamental capability of unmanned surface vehicles (USVs). However, achieving this capability is challenging due to reduced controllability and increased sensitivity to external disturbances during deceleration in the berthing process. This paper presents an autonomous berthing system with transition logic for three berthing strategies-bow-first, side-first, and stern-first-which has been developed and validated. The control strategies employed for berthing include north-east-down (NED) frame-based and body-fixed frame-based position control.The system was implemented on a small-scale catamaran USV equipped with a Pixhawk-based flight controller for field experiments. The results demonstrated that both control strategies successfully completed the berthing process, exhibiting differences in control behavior.