Tytuł: The autonomous navigation system of a sea-going vessel

Autor/Autorzy: Pietrzykowski Z., Wołejsza P., Nozdrzykowski Ł., Borkowski P., Banaś P., Magaj P., Chomski J., Mąka M., Mielniczuk S., Pańka A., Hatłas - Sowińska P., Kulbiej E., Nozdrzykowska M.

Miejsce publikacji: Ocean Engineering,2022, 261, art.. No. 112104

Rok: 2022

Słowa kluczowe: Automatic communication; Autonomous navigation; Collision avoidance

Abstrakt: We propose an integrated comprehensive system of an Autonomous Surface Vessel (ASV), dedicated to ships with various degrees of autonomy. The system performs a variety of tasks aimed at safe voyage execution. The use of basic and additional information sources is envisaged, including data from unmanned remotely controlled and autonomous aerial vehicles, to increase situational awareness. After defining the assumptions and devising the architecture of the system, we built its model. The key elements of the model, collision avoidance and automatic communication modules, are capable of developing and agreeing on manoeuvres between autonomous vessels in the negotiation process. The model was implemented as a real time system and verified in three stages: laboratory tests, quasi-real tests using physical models of ships and in real operational conditions on board ships at sea. The research results have confirmed the correctness of the assumptions, designed system architecture and developed algorithms.

Tytuł: The Algorithm of Determining an Anti-Collision Manoeuvre Trajectory Based on the Interpolation of Ship’s State Vector

Autor/Autorzy: Piotr Borkowski, Zbigniew Pietrzykowski, Janusz Magaj

Miejsce publikacji: Sensors, vol. 21, no. 16, art. no. 5332, pp. 1-16

Rok: 2021

Słowa kluczowe: autonomous sea-going vessel, anti-collision manoeuvre, ship’s state vector, interpolation, Dijkstra’s algorithm

Abstrakt: The determination of a ship’s safe trajectory in collision situations at sea is one of the basic functions in autonomous navigation of ships. While planning a collision avoiding manoeuvre in open waters, the navigator has to take into account the ships manoeuvrability and hydrometeorological conditions. To this end, the ship’s state vector is predicted—position coordinates, speed, heading, and other movement parameters—at fixed time intervals for different steering scenarios. One possible way to solve this problem is a method using the interpolation of the ship’s state vector based on the data from measurements conducted during the sea trials of the ship. This article presents the interpolating function within any convex quadrilateral with the nodes being its vertices. The proposed function interpolates the parameters of the ship’s state vector for the specified point of a plane, where the values in the interpolation nodes are data obtained from measurements performed during a series of turning circle tests, conducted for different starting conditions and various rudder settings. The proposed method of interpolation was used in the process of determining the anti-collision manoeuvre trajectory. The mechanism is based on the principles of a modified Dijkstra algorithm, in which the graph takes the form of a regular network of points. The transition between the graph vertices depends on the safe passing level of other objects and the degree of departure from the planned route. The determined shortest path between the starting vertex and the target vertex is the optimal solution for the discrete space of solutions. The algorithm for determining the trajectory of the anti-collision manoeuvre was implemented in autonomous sea-going vessel technology. This article presents the results of laboratory tests and tests conducted under quasi-real conditions using physical ship models. The experiments confirmed the effective operation of the developed algorithm of the determination of the anti-collision manoeuvre trajectory in the technological framework of autonomous ship navigation.

Tytuł: Adaptive System for steering a Ship Along the Desired Route

Autor/Autorzy: Piotr Borkowski

Miejsce publikacji: Mathematics, vol. 6, no. 10, art. no. 196, pp. 1-11

Rok: 2018

Słowa kluczowe: track-keeping, automatic ship control, adaptive control system, linear quadratic regulator (LQR)

Abstrakt: An adaptive ship steering system along a preset track is an example of an intelligent system. An optimal linear quadratic regulator (LQR) regulator with a symmetric indicator of control quality was adopted as the control algorithm. The model identification was based on the continuous version of the least squares method. A significant part of the article presents the proof of the stability of the proposed system. The results of the calculation experiments are provided to confirm the effective and correct working of the system.

Tytuł: Numerical Modeling of Wave Disturbances in the Process of Ship Movement Control

Autor/Autorzy: Piotr Borkowski

Miejsce publikacji: Algorithms, vol. 11, no. 9, art. no. 130, pp. 1-10

Rok: 2018

Słowa kluczowe: sea waves, wave disturbance modelling, spectrum of wave angular speed

Abstrakt: The article presents a numerical model of sea wave generation as an implementation of the stochastic process with a spectrum of wave angular velocity. Based on the wave spectrum, a forming filter is determined, and its input is fed with white noise. The resulting signal added to the angular speed of a ship represents disturbances acting on the ship’s hull as a result of wave impact. The model was used for simulation tests of the influence of disturbances on the course stabilization system of the ship.

Tytuł: Inference Engine in an Intelligent Ship Course-Keeping System

Autor/Autorzy: Piotr Borkowski

Miejsce publikacji: Computational Intelligence and Neuroscience, vol. 2017, art. no. 2561383, pp. 1-9

Rok: 2017

Słowa kluczowe: ship course stability; expert system; intelligent control system

Abstrakt: The article presents an original design of an expert system, whose function is to automatically stabilize ship’s course. The focus is put on the inference engine, a mechanism that consists of two functional components. One is responsible for the construction of state space regions, implemented on the basis of properly processed signals recorded by sensors from the input and output of an object. The other component is responsible for generating a control decision based on the knowledge obtained in the first module. The computing experiments described herein prove the effective and correct operation of the proposed system.

Tytuł: The Ship Movement Trajectory Prediction Algorithm Using Navigational Data Fusion

Autor/Autorzy: Piotr Borkowski

Miejsce publikacji: Sensors, vol. 17, no. 6, art. no. 1432, pp. 1-12

Rok: 2017

Słowa kluczowe: prediction of ship movement trajectory, navigational data fusion, navigational decision support system

Abstrakt: It is essential for the marine navigator conducting maneuvers of his ship at sea to know future positions of himself and target ships in a specific time span to effectively solve collision situations. This article presents an algorithm of ship movement trajectory prediction, which, through data fusion, takes into account measurements of the ship’s current position from a number of doubled autonomous devices. This increases the reliability and accuracy of prediction. The algorithm has been implemented in NAVDEC, a navigation decision support system and practically used on board ships.

Tytuł: Decision Support in Collision Situations at Sea

Autor/Autorzy: Zbigniew Pietrzykowski, Piotr Wołejsza, Piotr Borkowski

Miejsce publikacji: Journal of Navigation, vol. 70, no. 3, pp. 447-464

Rok: 2017

Słowa kluczowe: navigation, collision avoidance, decision support system

Abstrakt: The known navigational systems in use perform information functions and as such are helpful in the process of safe conduct of a vessel. One of the ways to assist in reducing the number of marine accidents is the development of systems which perform decision support functions, i.e. automatically generate solutions to collision situations. The use of information (and communication) technologies including knowledge engineering allows the generation of proposals for anti-collision manoeuvres taking into account the COLREGs. Demand for further enhancement of navigational safety by limiting human errors has initiated a trend to convert navigational information systems into decision support systems. The implementation of decision support systems will potentially reduce the number of human errors, which translates into a reduction of accidents at sea and their adverse consequences. This paper presents a summary of the research to date on the navigational decision support system NAVDEC. The system has been positively verified in laboratory conditions and in field tests – on a motor ferry and a sailing ship. Challenges associated with the development and implementation of such systems are outlined.