Ship Course Research Articles

ADP-based adaptive control of ship course tracking system with prescribed performance

In this paper, an adaptive dynamic programing (ADP)-based adaptive control problem is studied for the ship course tracking system with prescribed performance. Firstly, the complex sea conditions will bring difficulty to ship course tracking when unmanned ship sailing on sea. In order to overcome this difficulty, a prescribed performance feedforward term is designed in the controller to improve the course tracking ability of ship. Secondly, by defining a cost function, an ADP technology is exploited to achieve an optimal control of ship course tracking system. Finally, the stability of the closed loop system is turned out by Lyapunov stability theory and all signals are uniformly ultimately bounded (UUB). Simulation results validate the effectiveness of the proposed method.

Comparison Between Cubic and Quadratic Models of Hydrodynamic Derivatives to the Ship Course Stability Index

Comparison Between Cubic and Quadratic Models of Hydrodynamic Derivatives to the Ship Course Stability Index

Adaptive complementary sliding mode control of ship course under environmental disturbance

In this paper, an adaptive complementary sliding mode control strategy based on nonlinear extended state observer (NESO) is proposed for the ship course tracking control subject to environmental disturbances. By introducing the adaptive law, the system uncertainty is estimated and adjusted, so that the boundary layer of the complementary sliding mode control can realize dynamic changes and ensure the system robustness. At the same time, the auxiliary control system is introduced to compensate the complementary sliding mode control law to guarantee the system stability under finite actuation. For the environmental disturbances of the heading process, a NESO is designed for real-time estimation and compensated to the adaptive complementary sliding mode control law to improve the robustness of the system. The closed-loop stability is proved, and simulation results show that the control strategy effectively improves the tracking accuracy and robustness of the system.

Seafarer competency analysis: Data-driven model in restricted waters using Bayesian networks

Despite the efforts of maritime authorities to enhance seafarer competencies through the International Convention on Standards of Training, Certification and Watchkeeping for Seafarers (STCW), human error remains a leading cause of maritime accidents. To thoroughly investigate the impact of various human errors among seafarers on accidents, this paper aims to examine the relationships between seafarer competencies and maritime accidents using a data-driven approach from the perspective of bridge resource management (BRM). Through analysis of historical maritime accident reports, the dataset of seafarer competencies associated with maritime accidents is established. The least absolute shrinkage and selection operator (LASSO) method is employed to identify the critical seafarer competencies for accident prevention. Then, a data-driven Bayesian Network (BN) model, based on a Tree Augmented Naive Bayes (TAN) method, is constructed to reveal the relationship between seafarer competencies and accident types, which are validated by sensitivity analysis and case study. The results indicate that the key seafarer competencies for all maritime accidents are ‘Maneuvers’, ‘Amend/maintain ship course’, ‘Decision making’, ‘Cognitive capacity’, ‘Information’, ‘Procedure operations’, ‘Situational awareness’ and ‘Communication’. Moreover, the study underscores the importance of leveraging lessons learned from past accidents to mitigate risks and ensure safe maritime operations. The findings contribute to a deeper understanding of the dynamics between seafarer competencies and accident types, unveiling the joint impact of different seafarer competencies on maritime accidents. This perspective offers valuable insights for maritime authorities in strengthening maritime safety regulations.

Finite-Time Disturbance Observer-Based Adaptive Course Control for Surface Ships.

In this paper, a finite-time disturbance observer-based adaptive control strategy is proposed for the ship course control system subject to input saturation and external disturbances. Based on the Gaussian error function, a smooth saturation model is designed to avoid the input saturation of the system and reduce steering engine vibrations, and an auxiliary dynamic system is introduced to compensate for the effect of the rudder angle input inconsistency on the system. By constructing an auxiliary dynamic, a finite-time disturbance observer is designed to approximate the external disturbance of the system; an adaptive updating law is also constructed to estimate the upper bound of the derivative of the external disturbance. Combining the finite-time disturbance observer with the auxiliary dynamic system, a novel adaptive ship course control law is proposed by using the hyperbolic tangent function. Moreover, according to LaSalle's Invariance Principle, a system stability analysis method with loose stability conditions and easy realizations is designed, while the stability of the closed-loop system and the ultimately uniformly boundedness of all its signals are proven. Finally, the course control simulation analysis of a surface ship is carried out. The results show that the proposed control law has a strong resistance to external disturbances and a strong non-fragility to system parameter perturbations, which ensure that the course control system has great control performance.

Minimization of a ship's magnetic signature under external field conditions using a multi-dipole model

The paper addresses the innovative issue of minimizing the ship's magnetic signature under any external field conditions, i.e., for arbitrary values of ambient field modulus and magnetic inclination. Varying values of the external field, depending on the current geographical location, affect only the induced part of ship's magnetization. A practical problem in minimizing the ship signature is separating permanent magnetization from induced magnetization. When the ship position changes, a signature measurement has to be made under new magnetic field conditions to update the currents in the coils. This is impractical or even difficult to do (due to the need for a measuring ground), so there is a need to predict the ship's magnetization value in arbitrary geographical location conditions based on the reference signature determined on the measuring ground. In particular, the model predicting the signatures at a new geographical location must be able to separate the two types of magnetization, as permanent magnetization is independent of external conditions. In this paper, a FEM model of the vessel is first embedded in an external field and permanent magnetization is simulated using DC coils placed inside the model. Then, using the previously developed rules for data acquisition and determination of model parameters, a multi-dipole model is synthesized in which the induced and permanent parts are separated. The multi-dipole model thus developed has been successfully confronted with the initial model in FEM environment. The separation of permanent and induced magnetization allows the latter to be scaled according to new values of the external field. In the paper, the situation of determining a signature at one geographical position and its projection onto two other positions is analyzed. Having determined the signature with a high degree of accuracy anywhere in the world, it is possible to perform classical signature minimization by determining DC currents in coils placed inside the ship's hull. The paper also analyzes the effectiveness of ship's signature minimization and the influence of ship's course on the signature value. The advantage of the method presented in this paper is an integrated approach to the issue of scaling and minimization of ship magnetic signature, which has not been presented in the literature on such a scale before.

The anchorage in cramped travel conditions

It is known that the safety of the anchorage is largely determined by the correct choice of the anchorage location, the depth and type of soil, the dimensions of the water area, protection from wind exposure, the presence of currents in the anchorage. Parking on sea raids in terms of the limited water area does not pose any special problems. In river conditions, the raids are located in close proximity to the ship's passage and are limited in width. Therefore, the question of the width of the strip occupied by the anchored vessel is important. Vessels on the river usually stand on the bow anchor against the current, but quite often, with strong crosswinds, it is necessary to give up the stern anchor in order to reduce the width of the lane occupied by the vessel and not interfere with the movement of passing vessels. The paper presents studies of safe conditions for anchoring ships in river conditions with wind in a limited-sized water area at different flow speeds. Calculated dependences are obtained for determining the transverse size of the water area occupied by a vessel standing at the bow anchor, bow and stern anchors with respect to the axis of the ship's course, depending on the speed of the current, wind speeds and direction.

Synthesis of ship systems optimal regulators based on matrix inequalities

The output and state regulators synthesis for ship control systems based on linear matrix inequalities using the CVX software package for solving optimization problems by the method of semi-definite programming is considered. Estimates parameters for regulators providing asymptotically stable systems regimes on Lyapunov inequalities solutions sets are obtained. An algorithm for controlling the ship course using a robust regulator in state feedback, followed by the use of CVX technologies to implement the minimum energy consumption control algorithm, is presented. The control vector estimation is reduced to the minimization of the L2 norm and it is performed in two stages, namely, the best mode is first determined, and then the mode under constraints is defined. The use of Lyapunov inequalities with the calculations implementation in CVX format on proprietary solvers has allowed us to obtain compact program texts and expand the set of restrictions introduced. In the algorithm for solving the boundary value problem of controlling a discrete model of an object, in contrast to existing optimization methods, a mode of transfer from the initial state to the final one with the right boundary, not necessarily equal to zero, is implemented. For a class of observable and controllable time–invariant systems, using the Krylov’s function contained in the MATLAB gallery of functions, L2‑norms to be minimized are formed. Examples of regulator calculations with a given degree of stability and optimal systems, confirming proposed solutions correctness, are given.

Experimental study on the course stability of a towed barge model

The course instability problem of towed objects is discussed in the paper. It is noted that many non-selfpropelled vessels do not have directional stability, as a result of which they make oscillatory movements relative to the course of the towing ship. Increased yaw rate leads to a decrease in towing speed, an increase in loads on the elements of the towing device and a significant increase in the width of the running lane. These factors can lead to an emergency and significantly complicate the towing process, especially on inland waterways. Two main ways to increase directional stability are considered. These are towing “on V-line”, that is a system in which the towing rope is divided into two parts and attached to two points of the towed barge, located symmetrically relative to the centerline, and the installation of skegs in the stern. To determine the effect of these methods, tests of a model of the mixed riversea navigation oil barge 2731 are carried out in calm deep water conditions in the experimental tank of the Admiral Makarov State University of Maritime and Inland Shipping. The root end of the towing rope is attached to the pylon of the towing tank trolley and, thus, the reverse influence of the barge on the characteristics of the tug movement is not taken into account. Sixteen options are considered. The half-width of the running lane is taken as a criterion for the stability of barge movement. As follows from the test results, with increasing towing speed and towing rope length, the width of the running lane increases slightly. The installation of end washers on the skegs has no effect on the stability of the barge. To reduce the width of the running lane occupied by the barge, it is recommended to use towing “on the V-line” and use skegs with fixed flaps.

PERFORMANCE OF SHIP NAVIGATION WAVE FILTERS WITH LOW ENCOUNTER FREQUENCY IN FOLLOWING SEAS

The effect of waves in the ship's autopilot is commonly considered as a part of the control system using a wave filter. The task of the wave filter is to remove the wave-induced motions from the measurements before they are used in the feedback control system. By not counteracting the wave-frequency motions when controlling course and speed, the autopilot avoids unnecessary wear and tear on the steering system. However, in following seas (with the wave direction being approximately in the same direction as the ship's course) the wave-frequency dynamics can be within the desired bandwidth of the course controller, since the wave encounter frequency can be very low. This paper compares the performance of different wave filters in following to quartering sea conditions, when considering different models, measurements and filtering techniques.

Development of a Ship's Course Controller using μ-synthesis

The article describes the procedure for designing a robust controller for controlling the course of sea vessels exposed to sea waves using µ-synthesis. To this end, practical knowledge of the vessel is used to obtain a linear design model with parametric uncertainties describing the dynamics of the vessel. Appropriate frequency weighting functions are selected to provide the required performance characteristics during the controller design phase. The proposed model and then the weighting functions are used to design a robust controller. The problem of wave filtering in the low-frequency range is also considered during the modeling and design of the controller. The key contribution of the paper is that it provides system designers with a methodology for obtaining uncertain linearized ship models that naturally fit within the framework of µ-synthesis control theory, and it describes, in a systematic manner, the various stages of the controller design process. In addition, the document contains detailed information on methods for analyzing robust systems and their modeling.

Generalized fuzzy hyperbolic model based ship course system control in the presence of complex noise

To solve the ship course control problem with nonlinear terms, input saturation, and complex noise, this paper proposes a saturated ship course control method with complex noise based on generalized fuzzy hyperbolic model (GFHM). Due to the characteristics of fewer identification parameters, GFHM can simplify the complexity of traditional ship fuzzy models. GFHM is more suitable for multi-variable nonlinear systems such as ships of which variables are limited and difficult to measure. Furthermore, to deal with the input rudder angle saturation problem caused by the limited capability to compensate the shipboard equipment controller, an auxiliary system is proposed. And the complex noise in the navigation environment is described by the random process. Then, a new type of ship fuzzy course controller is designed based on the theoretical framework of random differential equations (RDEs) and it is proved that the ship course system under the proposed GFHM-based controller is noise-to-state stable in probability (NSS-P) and the state is an asymptotic gain in probability (AG-P). The simulation results show that the proposed algorithm in this paper can effectively control the ship’s course.

Integrating k-means Clustering and LSTM for Enhanced Ship Heading Prediction in Oblique Stern Wave

The stability of navigation in waves is crucial for ships, and the effect of the waves on navigation stability is complicated. Hence, the LSTM neural network technique is applied to predict the course changing of a ship in different wave conditions, where K-means clustering analysis is used for the category of the ship’s navigation data to improve the quality of the database. In this paper, the effect of the initial database obtained by the K-means clustering analysis on prediction accuracy is studied first. Then, different input features are used to establish the database to train the neural network, and the influence of the database by different input features on the accuracy of the navigation prediction is discussed and analyzed. Finally, multi-task learning is used to make the neural network better predict the navigation in various wave conditions. Using the improved neural network model, the course of an autopilot ship in waves is predicted, and the results show that the current database and the neural network model are accurate enough for the course prediction of the autopilot ship in waves.

ВИЗНАЧЕННЯ ТА ВРАХУВАННЯ СИСТЕМАТИЧНИХ ПОХИБОК ПРИ ВИМІРЮВАННІ НАВІГАЦІЙНИХ ГЛИБИН

The scientific study considers the issue of studying the features and determining the inherent values of systematic errors that occur when measuring navigation depths with multibeam echosounders, the elimination of these errors from the measurement results, which requires a special organization and methodology for performing multibeam echosounders tests. Systematic errors of navigation data can affect as on the magnitude of the depth itself, as well as on its planned position, and their influence should be evaluated after studying the angular measurements by echo sounder beams and calibration. The calibration of multi-beam systems, as well as the horizontal and vertical movements of the vessel, is much more significant and complicated compared to the calibration of single-beam systems. It is necessary to perform system accuracy control tests to confirm the reliability of multibeam echosounder data. These tests should preferably be carried out on board before taking depth measurements. For this, it is necessary to capture data, process and edit them in real time. Periodic performance of accurate calibration and testing is necessary to confirm that the multibeam survey meets the accuracy requirements. Multibeam echosounders calibration tests are performed with the aim of minimizing errors, taking into account the delay time of data acquisition, sea waves and changes in the ship's course. Keywords: multibeam echosounder, systematic errors, sensor calibration, hydrographic surveys, relief of the seabed, marine navigation chart, measured tacks, survey software.

Design a robust quantitative feedback theory controller for cyber-physical systems: ship course control problem

Design a robust quantitative feedback theory controller for cyber-physical systems: ship course control problem

Time series prediction of ship course keeping in waves using higher order dynamic mode decomposition

A novel reduced-order model (ROM) based on higher order dynamic mode decomposition (HODMD) is proposed for the time series prediction of ship course-keeping motion in waves. The proposed ROM is validated by using the data of course-keeping tests of an ONR tumblehome ship model. First, modes are decomposed from the model test data by standard DMD and HODMD, and the dominant modes are selected according to the energy index. Then, the decomposed dominant modes are used to reconstruct and predict the dynamics of ship motion. The dynamic characteristics in the dynamical systems are revealed according to the energy index, growth rates, and frequencies of the decomposed modes. In addition, the effects of the tunable parameter in HODMD on prediction accuracy and computational times are analyzed by a parametric study. The prediction results by HODMD show better agreement with the model test data than those by standard DMD.

Observer-based [formula omitted] fuzzy fault-tolerant switching control for ship course tracking with steering machine fault detection

To enhance the robustness of ship autopilot (SA) system with nonlinear dynamics, unmeasured states, and unknown steering machine fault, an observer-based H∞ fuzzy fault-tolerant switching control for ship course tracking is proposed. Firstly, a global Takagi–Sugeno (T-S) fuzzy nonlinear ship autopilot (NSA) is developed with full consideration of ship steering characteristics. And the actual navigation data collected from a real ship are used to verify the reasonableness and feasibility of NSA model. Then, virtual fuzzy observers (VFOs) for both fault-free and faulty systems are proposed to estimate the unmeasured states and unknown fault simultaneously, and compensate for the faulty system by using the fault estimates. Accordingly, the VFO-based H∞ robust controller (VFO-HRC) and fault-tolerant controller (VFO-HFTC) are designed. Subsequently, a smoothed Z-score-based fault detection and alarm (FDA) is developed to provide switching signals for which the controller and its corresponding observer should be invoked. Finally, simulation results on the “Yulong” ship demonstrate the effectiveness of the developed control method.

Analysis of Collision Hazard Prevention With Operating Radar NICD – 453 Type On MV Amrta Jaya 1

The navigation system is the key to the safety of the ship in carrying out the voyage. RADAR will be very useful during bad weather, foggy conditions and sailing at night, especially when navigational instructions such as beacons, buoys, hills or buildings cannot be visually observed. So prospective ship officers must understand and understand to use RADAR navigation tools. To find out the target position and reduce the accident rate in the shipping lane, the role of RADAR in supporting shipping safety is needed. This study aims to analyze the prevention of collision hazards by using the Maneuvering Board in the operation of the Binocular RADAR at MV AMRTA JAYA 1. The type of research used in this study is quantitative research. In this case the data collection techniques used are documentation and observation. Documentation is in the form of searching for information in the form of books and documents, while observation is in the form of an approach to the object of research. From the results of research conducted, it can be seen that the method used to calculate the RADAR Plotting Sheet can be done by theoretical methods with formulas and scale methods with mathematical logic. The two methods can be used with the same results but with different time efficiency. The use of muvering boards and RADAR Plotting Sheet calculations can help identify the presence or absence of a collision hazard, and help estimate the closest distance, time taken, course and speed of the target ship.

Conquering the Pacific: An Unknown Mariner and the Final Great Voyage of the Age of Discovery

Conquering the Pacific: An Unknown Mariner and the Final Great Voyage of the Age of Discovery

Research on 3-DOF stabilized control system of ship propulsion-assisting sail

In recent years, wind-assisted ship propulsion (WASP) has become an important technology that can reduce the energy consumption of shipping. With different wind directions, a propulsion-assisting sail is rotated in azimuth to achieve maximum thrust along the ship's course. Most existing servo systems enable azimuth control of sails. However, the ship's attitude motion will affect the energy reduction of the sail. In this paper, this negative influence is described and demonstrated. The idea of three-degree-of-freedom (3-DOF) sail control is presented, and the energy reduction improved by the method is verified. Then, a 3-DOF stabilized control system of the ship propulsion-assisting sail is proposed to achieve azimuth tracking of the sail and compensate for attitude deviation caused by the ship. Considering the attitude target and the asymmetric structure of the sail, a kinematics solution and a dynamic model are established. Regarding the coupling characteristics of multivariable systems, inverse dynamics with a kernel-based multilayer extreme learning machine (ML-KELM) are designed to decouple the origin system. Finally, a numerical simulation was performed, and a principle prototype was developed. Results show that the designed control strategy eliminates the coupling of the original system, and the proposed system ensures the attitude stability of the sail.