Design of a safety operational envelope protection system for a submarine

A safety operational envelope (SOE) is an area that guarantees the safety of a submarine from accidents, such as jamming and flooding. In this study, a submarine envelope protection system (EPS) was designed to prevent submarine excursion from the SOE. Modeling of the hull force, propeller force, and main ballast tank blowing was performed. The SOE was established based on a crash stop and emergency rising maneuver simulation. In the estimation model, a linear compensator and neural network are employed to estimate the submarine dynamics. The command limit is calculated using the estimation model and the dynamic trim algorithm, and it is restricted by the limit avoidance. The EPS was applied to a submarine maneuvering simulation program and its performance was verified by a depth change simulation. The designed EPS prevents the submarine from exceeding the limit boundary and the control system can thereby enhance the operational stability.