Hazard analysis of autonomous vessel operation during the interaction and execution between remote operation centre controller and onboard controllers

A critical challenge in the safe operation of autonomous vessels is ensuring that control commands are executed accurately and promptly by both shore-side and onboard systems. In this paper, we build on a use case of an autonomous ship, where the control hierarchy includes Human Operators on the shoreside, along with the Ship Motion Controller, Power Management System, and Battery Management System, among other controllers on the shipside. Incorrect execution of control actions by these controllers can lead to hazardous situations of varying severity. This study aims to identify and analyze hazards related to these four controllers and provide insights into how inadequate control may occur and create hazardous situations with the controllers. Recently, STPA has emerged as the mainstream approach for identifying hazards resulting from control action failures. Therefore, this study applies the System Theoretic Process Analysis (STPA) method to explore how control actions of different controllers might fail, ensuring safe operation. A control structure hierarchy has been developed that identifies (1) control actions and (2) feedback signals between controllers based on their responsibilities. Using STPA, a total of 127 unsafe control actions are identified that could result in hazards. We classify the significance of Unsafe Control Actions based on hazard severity, operational mode, and suggest the level of attention each controller requires. The results offer a structured foundation for prioritizing safety–critical control actions in battery-powered autonomous ships, facilitating more effective risk mitigation strategies for designers, operators, and regulators.