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Bow Crossing Range correlation of small vessels – AIS data analysis with prospective application to autonomous ships

Stolzmann Łukasz

Scientific Journal of Gdynia Maritime University

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2022

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nr 121

41--52

EN

The development of technology has reduced the crews of ships. This trend leads to at least partial elimination of human crews in favour of autonomous ships. As more and more of them will be introduced, a safety problem arises when manoeuvring the ships in relation to each other. Therefore, there is a need to identify the factors that have an impact on determining how to maintain safe distances between ships in order to find relationships that will be useful for the development of autonomous ships. This can currently only be analysed on samples of manned vessels. Therefore, this paper aims to analyse the correlation of the Bow Crossing Range (BCR) with other ship-related data provided by AIS on ships up to 100 m long. The results of this study may be found interesting by academia, maritime industry, and autonomous ship developers.

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Framework of an evolutionary multi-objective optimisation method for planning a safe trajectory for a marine autonomous surface ship

Szłapczyński Rafał, Ghaemi Hossein

Polish Maritime Research

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2019

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nr 4

69--79

EN

This paper represents the first stage of research into a multi-objective method of planning safe trajectories for marine autonomous surface ships (MASSs) involved in encounter situations. Our method applies an evolutionary multiobjective optimisation (EMO) approach to pursue three objectives: minimisation of the risk of collision, minimisation of fuel consumption due to collision avoidance manoeuvres, and minimisation of the extra time spent on collision avoidance manoeuvres. Until now, a fully multi-objective optimisation has not been applied to the real-time problem of planning safe trajectories; instead, this optimisation problem has usually been reduced to a single aggregated cost function covering all objectives. The aim is to develop a method of planning safe trajectories for MASSs that is able to simultaneously pursue the three abovementioned objectives, make decisions in real time and without interaction with a human operator, handle basic types of encounters (in open or restricted waters, and in good or restricted visibility) and guarantee compliance with the International Regulations for Preventing Collisions at Sea. It should also be mentioned that optimisation of the system based on each criterion may occur at the cost of the others, so a reasonable balance is applied here by means of a configurable trade-off. This is done throughout the EMO process by means of modified Pareto dominance rules and by using a multi-criteria decision-making phase to filter the output Pareto set and choose the final solution.

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Modelling of ship’s trajectory planning in collision situations by hybrid genetic algorithm

Ni S., Liu Z., Cai Y., Wang X.

Polish Maritime Research

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2018

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nr 3

14--25

EN

Ship collision-avoidance trajectory planning aims at searching for a theoretical safe-critical trajectory in accordance with COLREGs and good seamanship. In this paper, a novel optimal trajectory planning based on hybrid genetic algorithm is presented for ship collision avoidance in the open sea. The proposed formulation is established based on the theory of the Multiple Genetic Algorithm (MPGA) and Nonlinear Programming, which not only overcomes the inherent deficiency of the Genetic Algorithm (GA) for premature convergence, but also guarantees the practicality and consistency of the optimal trajectory. Meanwhile, the encounter type as well as the obligation of collision avoidance is determined according to COLREGs, which is then considered as the restricted condition for the operation of population initialization. Finally, this trajectory planning model is evaluated with a set of test cases simulating various traffic scenarios to demonstrate the feasibility and superiority of the optimal trajectory.

4

Modelowanie CFD osiadania statków kontenerowych podczas manewru wymijania na torze wodnym

Jachowski J., Krata P.

Autobusy : technika, eksploatacja, systemy transportowe

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2016

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R. 17, nr 4

64--71

PL

W artykule omówiono badania nad zastosowaniem zaawansowanych obliczeń numerycznej mechaniki płynów do wyznaczania trajektorii ruchu (w sześciu stopniach swobody) statku morskiego żeglującego na akwenie ograniczonym podczas manewru wymijania z innym statkiem. Uwzględniono jednocześnie zarówno oddziaływanie dna i brzegów kanału o zadanej geometrii jak również oddziaływanie wymijanego statku, co jest podejściem nowatorskim na skalę światową. Wyniki symulacji przeanalizowano pod wzglądem hydrodynamicznego zjawiska osiadania, powstającego podczas przejścia statku przez akwen ograniczony głębokością i brzegami kanału przy jednoczesnej interakcji z wymijanym statkiem. W obliczeniach wykorzystano geometrię typowego statku kontenerowego.

EN

Paper describes a research into ship’s squat phenomenon which is related to the safe entering of large ships into contemporary existing sea harbors. As the significant research effort in ship hydromechanics is devoted in recent years to the practical navigation problems, the Authors follow this trend and addressed the squat by means of CFD numerical simulations. The analysis of 6 DOF ship motion was performed, including the effects of shallow water, horizontal restrictions, extend of a channel and especially ship squat during passing by maneuver at a waterway. An exemplary case-study is carried out for a large container vessel. The obtained results were experimentally verified by comparison to one German experiment and own models tests. Such complex approach is a novelty worldwide.

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Customized crossover in evolutionary sets of safe ship trajectories

Szłapczyński R., Szłapczyńska J.

International Journal of Applied Mathematics and Computer Science

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2012

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Vol. 22, no. 4

999-1009

EN

The paper presents selected aspects of evolutionary sets of safe ship trajectories-a method which applies evolutionary algorithms and some of the assumptions of game theory to solving ship encounter situations. For given positions and motion parameters of the ships, the method finds a near optimal set of safe trajectories of all ships involved in an encounter. The method works in real time and the solutions must be returned within one minute, which enforces speeding up the optimisation process. During the development of the method the authors tested various problem-dedicated crossover operators to obtain the best performance. The results of that research are given here. The paper includes a detailed description of these operators as well as statistical simulation results and examples of experiment results.