Ship Course Research Articles

Flexible guided anti-collision device for bridge pier protection against ship collision: Numerical simulation and ship collision field test

The flexible guided anti-collision device (FGAD) can prolong the impact time between ship and pier, so that the ship has enough time and space to turn and deviate from the pier. In this way, the ship can retain most of the kinetic energy, and the impact force on the pier can be greatly reduced. Both of ship and pier can be protected by the FGAD. In this paper, the dynamic response and the energy-dissipation capacity of FGAD are firstly studied by the numerical simulation of ship-bridge collision process. The results show that the FGAD can effectively turn the ship's course, and the concentrated force of collision is transformed into the distributed force, which significantly reduces the energy conversion and impact force. Then, an actual ship collision field test is carried out to investigate the effectiveness of the FGAD for reducing the impact force on the pier and turning the navigation direction of ship. The test results show that the FGAD can turn the ship's course with a little change of the ship speed after the collision. Most of the kinetic energy does not participate in the energy exchange and the impact force on the pier is significantly reduced. The FGAD realizes the design idea of protecting both the bridge and the ship. The application of engineering also confirms the effectiveness and reliability of the FGAD.

Overview of machine learning methods in maritime traffic monitoring based on Automatic Identification System

The Automatic Identification System (AIS) was introduced to increase maritime safety. Its messages contain information on the identification, position, speed and course of ships. AIS enables the tracking of ships, the establishment of corridors, the detection of unusual manoeuvres (piracy, terrorism, problems with the ship or crew), the optimisation of shipping channels, strategic planning and the increase of shipping efficiency, as well as the reduction of pollution. AIS data is processed using various machine learning techniques for the purpose of extracting vessel trajectories, assessing collision risk, detecting maritime anomalies and analysing ship emissions to the environment. The development of machine learning techniques has a large and significant impact because they can quickly process a large amount of data and thus increase the safety and reliability of maritime transport. The paper gives an overview of the technical features and benefits of using AIS as well as the analysis of AIS data, algorithms for classifying and clustering AIS data and machine learning methods for detecting anomalies in maritime traffic.

Designing an optimal ship course-keeping system for an unknown object model via adaptive dynamic programming approach

The paper discusses the problem of ship autopilot design based on the adaptive (approximate) dynamic programming approach (ADP). The main objective of this paper is to propose the design of a ship's course controller within the framework of computational intelligence techniques, i.e. (in our case) based on model-free optimal regulation. This method is attractive in that it does not require knowledge of the system model to generate optimal process control. The key idea is to iteratively solve the Hamilton-Jacobi-Bellman (HJB) equation based on a simple value function approximator structure. In this way, by introducing such basic elements as evaluation and improvement, we are able to carry out an intelligent optimization process based only on the data received online. Thus, this is a kind of data-driven control methodology. The simulations of the ship course change process confirmed the high efficiency of the proposed controller. An important feature of this approach is also the elimination of the tuning problem.

A CONTROL SYSTEM FOR MOVEMENT AND DIVERGENCE OF UNMANNED SHIP ACCORDING TO COLREG

A variant of unmanned ship control system with obstacle avoidance in accordance with International Regulations for Preventing Collisions at Sea (COLREG) is proposed in the paper. The system consists of three subsystems: trajectory control subsystem, obstacle avoidance subsystem, course and speed control subsystem. The trajectory control subsystem generates a course that allows you to move along a predetermined trajectory. A gradient vector of the auxiliary function algorithm is used for this. In this algorithm, the alfa weight coefficient, which determines the degree of convergence of the unmanned ship to a given trajectory, is set. To ensure more efficient control convergence of the unmanned ship to a given trajectory, it is proposed to use the variable value of alfa, which depends on the condition of the coincidence of the unmanned ship course with the direction of the route and the value of alfa change for one iteration. The obstacle avoidance subsystem is based on the method of Velocity Obstacles, when all variants of the unmanned ship velocity vectors, at which a collision with an obstacle in the future is possible, are determined provided that the obstacle does not maneuver. The subsystem is activated when a dangerous situation occurs. The distance of the closest approach to the obstacle and the time of following to the point of the closest approach are calculated for identify a dangerous situation. Also, the subsystem implements a mechanism for determining the type of dangerous situation and compliance with COLREG. In total, four basic avoidance scenarios have been identified: head-on, crossing (obstacle moves to the left or right), and overtaking. To perform collision avoidance, the cost function of all variants of the course and speed is calculated, and the best variant is selected. The selected course and speed are transmitted to the course and speed control subsystem. The system is implemented in the Matlab / Simulink modeling environment. The simulation results confirmed the operability of the system, which ensures the movement of the unmanned ship along a given route and avoidance obstacles in case of dangerous situations in accordance with COLREG.

Численное моделирование самосогласованной динамики поверхностных вод, влекомых и взвешенных наносов: I. Влияние промышленной добычи песка на безопасность судоходства в русле р. Волга

A mathematical model of the joint dynamics of shallow waters, entrained and suspended sediments is constructed, which takes into account nonlinear fluid dynamics and bottom deformations. The dynamics of shallow waters is described by the Saint-Venant equations taking into account the spatially inhomogeneous distribution of the terrain. The transport of entrained sediments is described by the Exner equation generalized to the case of an inhomogeneous distribution of the parameters of the underlying surface. The dynamics of suspended sediments is described by the transport equation, which includes convective transport by water flow and the process of diffusion of the suspension in the liquid layer. For numerical integration of the Saint-Venant, Exner equations and suspended sediment dynamics, a stable and well-tested CSPH-TVD method of the second order of accuracy is used, the parallel CUDA algorithm of which is implemented in the form of a software package «EcoGIS-Simulation» for highperformance computing on supercomputers with graphics coprocessors (GPU). The conditions for the development of a quarry of non-metallic building materials (NSM) located at the mouth of the Partridge Volozhka of the Volga-Akhtuba floodplain on the 2549–2550 km section of the Volga River are considered. To study the safety of navigation from the lower reaches of the Volga hydroelectric dam to the entrance to the VDSK, numerical hydrodynamic modeling of the dynamics of channel processes in this section of the Volga River was carried out. Based on the results of mathematical modeling of the joint dynamics of surface waters, entrained and suspended sediments in the riverbed of the Volga River, it is concluded that the development of the NSM quarry considered in the work does not significantly affect the safety of navigation both along the main ship course «The lower reaches of the Volga hydroelectric dam — VDSK» and on additional — «Volgograd zaton» and «Volozhka Partridge».

Модальный синтез оценивателя неизмеряемых переменных состояния для системы стабилизации курса судна

The purpose of the study is to apply automation technologies and digitalization in estimating the unmeasurable variables of the ship course stabilization system to control the high-tech software and hardware and, thus, to intensify the use of ships at a qualitatively new level, as well as to improve the reliability and efficiency of their operation. It has been stated that estimating the vector of state variables in real time requires to use methods and computational algorithms 
 of stochastic and, in particular, binomial filtering. It is emphasized that for improving the reliability and accuracy of estimating the parameters of the system under perturbations of the roll angle, angular rotation speed or measurement noise there are required compromise solutions that take into account the required values of the system's speed and stability. It is shown that digitalization of mathematical and physical ship models, producing the adequate decisions, taking into account a wide range of environmental influences and navigation conditions allow to synthesize ship control complexes in the class of digital predictive systems with a transition to the control of unmanned objects. There has been considered the modal method of synthesis of the vector estimator of the state of full dimension (Kalman observer) which can obtain estimates of unmeasured state variables of the course stabilization system with measured output and input of the system by developing a model of the state of the extended system ‘object–observer’, which ensures stability of the ship on the course. A model and an algorithm for estimating unmeasured state variables by using binomial filtering algorithms, matrix laboratory tools and computer modeling technologies in the MATLAB environment are proposed. The proposed algorithm for the synthesis of a vector evaluator of unmeasured state variables is implemented in the form of a program compiled in MATLAB codes and demonstrated in calculating a two-dimensional dynamic observer for an unstable object of control. The obtained estimates of unmeasured variables, as well as the results of modeling the dynamic reactions of the course stabilization system correspond to the specified speed and stability transient processes of the ship object when transferring it into the steady state under the new initial conditions.

Assessment of the transport capabilities of inland waterways

The article is devoted to the assessment of the transport capabilities of inland waterways on the example of the Siberian region. As the main indicator of this assessment, the authors propose the product of the coefficient of the class of the depth of the ship's course of the river for the period of its operation. The introduction contains the normative documents on the basis of which the proposed methodology is based. It is proposed to calculate the resource of rivers according to two options: in the first – the guaranteed depth of the ship's course is used, in the second - the change in the class of the depth of the ship's course of the river during the entire navigation is taken into account. Based on the proposed methodology, calculations of the resources of the four main Siberian rivers were made. Thanks to this indicator, it became possible to calculate and compare the resources of rivers with different periods of operation and different depths of the ship's course. The Lena River has the least resource in the region, since its upper reaches are sharply limited by the depth of the ship's passage, and the lower reaches by the period of operation.

Substantiation of the hydraulic possibility of establishing guaranteed dimensions of the ship's course on the section R.Kama from the village of Bondyug to the village Kerchevsky

The establishment of guaranteed dimensions of the ship's course requires a systematic approach. An increase in the depth of the watercourse causes a landing of the water level, which can negatively affect the level regime of the water body and the ecological situation of the region. For the section of the Kama River from the village of Bondyug to the village. Kerchevsky conducted research on the possibility of establishing a guaranteed depth of 1.3 m for the expedition and navigation periods. As part of the research, the possibility of establishing guaranteed dimensions on the Upper Kama from the village of Bondyug to the village was revealed. Kerchevsky, taking into account the dredging and straightening works only for the extended expedition period of navigation.

Substantiation of conditions for the creation and use of navigable depths on the Upper Kama in the expedition period of navigation

The conditions for the creation and use of navigable depths on the Upper Kama were determined by studying the level regime in the section from Bondyug village to the Tyulkino urban settlement. On this section which is 97 km long, raft transportation is carried out only in the short-term full-flowing spring period, which limits the possibility of using water transport. In order to extend the period of withdrawal of rafts on the site and establish guaranteed dimensions of the ship's course, the proposed methodology substantiates the marks of the design levels for the reference hydraulic posts and evaluates the possibility of establishing guaranteed depths. The defining conditions for creating depths are the developed complex of track works and the hydraulic capabilities of the river, taking into account the peculiarities of channel deformations on the site. Recommendations on the organization of raft transportation depending on the depths in the extended expedition period are given.

Marine ship’s course stabilization based on an autopilot with a simple fuzzy controller

A simple method for generating a fuzzy course controller for a marine ship is presented. The controller is built without using training data. The new fuzzy controller uses conventional triangular sets, no complex overlaps, no complex expert judgments inherent in other types of fuzzy controllers. This approach makes it possible to synthesize a controller based on unified rules. The system is not hybrid and does not use other methods such as neural networks and reference models. The applicability of the proposed approach is demonstrated by an application for controlling the course of a marine ship in various modes. It is shown by means of simulation that the exchange rate stabilization system synthesized with the new fuzzy controller has robust properties.

Hybrid Circuit Actuator Design for Ship Course Control Experiment

This brief presents a low cost hardware-in-the-loop experimental design for large ship course control with actuator in the form of hybrid circuit, which can effectively capture the essential properties of friction and provide a more realistic environment to perform test. According to the Coulomb plus static friction model formulation, the velocity decision circuit, the absolute value circuit and the friction decision circuit are designed based on the basic circuit components and are validated by a series of simulations, respectively. Besides, the circuit of PID controller and the linear model of steering gear are also added to generate the closed-loop actuator. In addition, the model of the ship and the corresponding PID course controller are realized by the algorithm in the computer. The numerical model and the circuit implementation of realistic actuator can exchange information to establish a hardware-in-the-loop experimental platform. Finally, several experiments are carried out to verify the effectiveness of the proposed low-cost system.

Dual-channel LIDAR searching, positioning, tracking and landing system for rotorcraft from ships at sea

AbstractTo address the shortcomings of existing methods for rotorcraft searching, positioning, tracking and landing on a ship at sea, a dual-channel LIDAR searching, positioning, tracking and landing system (DCLSPTLS) is proposed in this paper, which utilises the multi-pulse laser echoes accumulation method and the physical phenomenon that the laser reflectivity of the ship deck in the near-infrared band is four orders of magnitude higher than that of the sea surface. The DCLSPTLS searching and positioning model, tracking model and landing model are established, respectively. The searching and positioning model can provide estimates of the azimuth angle, the distance of the ship relative to the rotorcraft and the ship's course. With the above parameters as inputs, the total tracking time and the direction of the rotorcraft tracking speed can be obtained by using the tracking model. The landing model can calculate the pitch and the roll angles of the ship's deck relative to the rotorcraft by using the least squares method and the laser irradiation coordinates. The simulation shows that the DCLSPTLS can realise the functions of rotorcraft searching, positioning, tracking and landing by using the above parameters. To verify the effectiveness of the DCLSPTLS, a functional test is performed using a rotorcraft and a model ship on a lake. The test results are consistent with the results of the simulation.

Energy saving method for ship weather routing optimization

In this paper, an improved three-dimensional dynamic programming algorithm for ship route optimization is proposed. As a consequence of the weather conditions and constraints, the ship course and speed are planned, and the optimal solution of ship route planning is generated. Compared with the actual navigation data of the VLCC oil tanker, the calculation accuracy of the method is verified by referring to the great circle route. Under the objective function of minimum FOC (fuel oil consumption) and ETA (estimated time of arrival), the economic benefits of the VLCC oil tanker per voyage are increased by 1.59% and 1.33% respectively, and ETA is shortened by 14.63h and 17.79h. In addition, the method also has the ability of other objective function optimization, weather updating and route updating, which can provide sufficient support for ship operators in route planning.

Fractional-Order PIλDμ Controller Using Adaptive Neural Fuzzy Model for Course Control of Underactuated Ships

For the uncertainty caused by the time-varying modeling parameters with the sailing speed in the course control of underactuated ships, a novel identification method based on an adaptive neural fuzzy model (ANFM) is proposed to approximate the inverse dynamic characteristics of the ship in this paper. This model adjusts both its own structure and parameters as it learns, and is able to automatically partition the input space, determine the number of membership functions and the number of fuzzy rules. The trained ANFM is used as an inverse controller, in parallel with a fractional-order PIλDμ controller for the course control of underactuated ships. Meanwhile, the sine wave curve and the sawtooth wave curve are considered as the input learning samples of ANFM, respectively, and the inverse dynamics simulation experiments of the ship are carried out. Two different ANFM structures are obtained, which are connected in parallel with the fractional-order PIλDμ controller respectively to control the course of ship. The simulation results show that the proposed method can effectively overcome the influence of uncertainty of ship modeling parameters, track the desired course quickly and effectively, and has a good control effect. Finally, comparative experiments of four different controllers are carried out, and the results show that the FO PIλDμ controller using ANFM has the advantages of small overshoot, short adjustment time, and precise control.

Method of Prompt Evasive Manuever Selection to Alter Ship's Course or Speed

One of the most important challenges of modern shipping is the problem of improving the level of safety at sea and enhancing accident-free ship operation. World fleet accident rates have a direct impact on both the safety of human life at sea and on the environment. Ship collisions have a particular place in accident statistics. They are caused by increasing ship deadweight, growing speeds, dense traffic and the presence of navigational hazards, which, combined, considerably increase navigation complexity, especially in coastal and restricted waters. These factors contribute to emergencies, incidents and situations, which, in turn, are characterized by rapidly changing circumstances. The aforementioned features of the navigation process call for the development and application of modern methods of operation and flexible evaluation of the situation at hand, as well as for the development of new approaches to evasive maneuver selection, including computer and information technologies, to ensure the safety of navigation. Thus, the development of modern methods and ways of prompt selection of an appropriate evasive maneuver to alter a ship's course or speed, which is the subject of this paper, is an important research trend. The paper also proposes a method of prompt evasive maneuver selection to prevent collisions by altering the ship's course or reducing its speed by active and passive braking. Analytical expressions used to calculate the limits of unacceptable ship course and ship speed values, taking into account the braking mode, are presented. The author's recommended optimum evasive maneuver is presented, and a technique of prompt evasive maneuver selection aimed at altering a ship’s course or speed by active and passive braking is developed.

Estimating the ship traffic in the Istanbul Strait through economic growth of region countries

The current study predicts the future course of ships passing through the İstanbul Strait. In this direction, considering that the world economy is the biggest factor in the demand for maritime transport, the relationship between the GDPs and trade volumes of the Black Sea states, and ship traffic is analyzed using regression estimation in two separate models. The included countries are Bulgaria, Georgia, Romania, Russia, Turkey and Ukraine. Then, considering the growth forecasts published by the IMF for the relevant states, it was estimated how much an increase in traffic would be in 2026 compared to 2020. Considering the coefficients obtained from the two models, in 2026, the GDP model proposes a 20.02% increase, and the trade volume model proposes a 28.8% increase in ship tonnage passing the strait. These results reveal the importance and necessity of strategies and projects developed to regulate the rise in strait traffic.

Implementasi Metode Propotional, Integral, Derifative (PID) Sebagai Kontrol Kapal Autonomous Dengan Sistem Waypoint Untuk Wahana Batimetri

Indonesia is the world's largest island nation with many islands and more seas than land. Because of the size of the Indonesian sea, oceanographic science is needed. Oceanographic learning involves the study of the underwater depths of the batimetric sciences. Batimetric science is crucial because it studies underwater depth. Batimetric processes in Indonesia today generally employ large vessels with manual control, resulting in the skill required of drivers at risk for obtained track data. With the problem, it has been designed to disrupt the autonomous control system with a pid waypoint system that would provide stable direction for the ship. The control system USES the arduino microcontroller which is used for processing data. The data obtained are data coordinates obtained from the GPS and the ship's navigation data obtained from the compass sensors. The data obtained will be processed and applied to pid methods. Of the pid process can be generated the degree degree required to power the servo motor connected to the ship's rudder. In this research USES four coordinate points of starting point, first goal point, second point of destination, and third point of goal. Once it reaches the third point of destination, the ship will return to its starting point. From the results of the testing done, the result is a kostanta pid score of KP =8, ki =5, kd = 3.5. Tests enabled the system that kept the ship's course steady as it should. So the ship goes on track.

Grey Wolf Optimization Based Active Disturbance Rejection Control Parameter Tuning for Ship Course

Grey Wolf Optimization Based Active Disturbance Rejection Control Parameter Tuning for Ship Course

CFD-based hydrodynamic analyses of ship course keeping control and turning performance in irregular waves

Ship manoeuvrability studies are usually carried out in calm and regular seas; however, an irregular sea state can better present the real operational conditions at sea, compared to both calm and regular seas. In this study, the manoeuvrability of a well-known benchmarking ship in an irregular sea state was investigated using a fully nonlinear unsteady RANS model. The JONSWAP spectrum was used to generate long-crested irregular seas with a significant wave height of 5m and a peak period of 12.4s in full scale, representing sea state 6. Comparisons with the ship manoeuvrability in both calm and regular seas were also made with a view to identifying the changes in the manoeuvring characteristics of the ship. The generated regular waves were characterised by the height and period equivalent to the average height and period of the irregular waves applied in this work. The ship is equipped with a single propeller with a semi-balanced horn rudder, and the propeller is simulated by an actuator disk model based on the body force method. In analysing the correlations between the ship manoeuvrability and the irregular waves, the findings of this study have demonstrated that the irregular waves may cause substantial changes in the course keeping capability and turning performance when compared to the inherent manoeuvring qualities in calm water. It is expected that the results of this work can provide a deeper insight into ship manoeuvrability in irregular waves as well as help masters and navigation officers in decision-making for ship handling actions in real sea states.

Design of ship course-keeping system via adaptive control techniques

The paper discusses the problem of ship autopilot design based on the input-output feedback linearization method combined with the adaptive control techniques. At first, the nonlinear ship model of the Norrbin type is linearized with the use of simple system nonlinearity cancellation. Since the exact values of the model parameters are not known to overcome the resulting inaccuracies, these parameters are tuned in such a way as to guarantee the asymptotic stability of the system. Some novelty is that by treating the load disturbance as an additional, unknown parameter of the system, we do not need to introduce an extra integral action to deal with the appearing steady-state error. The simulations of the ship course change process confirmed the high efficiency of the proposed controller despite the assumed uncertainty of the system parameters and environmental disturbances. An important feature of this approach is also the elimination of the tuning problem.