On the Application of the Smart Algorithm for Excessive Roll Motion Avoidance of Ocean-Going Vessels in Relevant Scenarios

During navigation at sea, autonomous ship systems must ensure adequate conduction to guarantee the same level of safety as any other vessel. A safe conduction of the vessel has to ensure, among other aspects, the avoidance of excessive motion of ships while in the seaway, especially in case of severe sea states. Excessive motions and excessive accelerations can arise during synchronous and parametric roll resonance. In this study, we present a smart system for roll resonance avoidance at sea, capable of identifying and distinguishing between parametric and synchronous resonances, based on the ship’s current sea state and operational condition. The proposed algorithm works on the time histories, recorded on board, of heave pitch and roll, using the first two data as indicators of the wave period. Indeed, roll motions, in case of parametric resonance, show a non-linear behavior with respect to wave frequencies. The algorithm accounts for two alert levels, depending on the severity of roll amplitude. In this paper, we report on the outcomes of the applications of the algorithm for excessive roll motion avoidance to different scenarios. In the absence of real data from the field, we use time histories obtained from numerical simulations and experimental tests in the laboratory. This study will help in testing and improving the current algorithm focusing on the calibration of the alert thresholds