Publications | Haitong Xu

2026

A LiDAR intensity-enhanced 3D object detection method for maritime autonomous navigation

Dongdong Guo, Yong Yin, Qianfeng Jing, and 2 more authors

2026

Cited by: 0

Abs DOI

For the Autonomous Maritime Navigation System, LiDAR 3D object detection is crucial for waterborne environment perception. However, complex dynamics and multi-scale objects, particularly small vessels, present significant accuracy challenges for current algorithms. To address these limitations, this study introduces point cloud intensity into the PointPillar detection network and proposes a novel 3D object detection method named Intensity-PointPillar. By incorporating average pooling and attention pooling into the encoding network, the method fully considers the local geometric details and point cloud intensity information within each pillar module, enhancing the feature representation capability of each pillar and thereby improving the model’s object detection performance. Additionally, a multi-branch detection head is introduced, along with a point cloud intensity loss function, to mitigate the inconsistency between the object classification branch and the position regression branch. The proposed method is trained and evaluated using two real-world ship LiDAR point cloud datasets. Experimental results demonstrate that the Intensity-PointPillar achieves significantly higher detection accuracy, with a mean Average Precision improvement of 31.6 % compared to the original network, thereby validating the effectiveness of the proposed method. © 2025 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license. http://creativecommons.org/licenses/by-nc-nd/4.0/

2025

Towards LLM Enhanced Decision: A Survey on Reinforcement Learning Based Ship Collision Avoidance

Yizhou Wu, Jin Liu, Xingye Li, and 4 more authors

Journal of Marine Science and EngineeringMore Information can be found here , 2025

Cited by:

Abs DOI HTML PDF Video

This comprehensive review examines the works of reinforcement learning (RL) in ship collision avoidance (SCA) from 2014 to the present, analyzing the methods designed for both single-agent and multi-agent collaborative paradigms. While prior research has demonstrated RL’s advantages in environmental adaptability, autonomous decision-making, and online optimization over traditional control methods, this study systematically addresses the algorithmic improvements, implementation challenges, and functional roles of RL techniques in SCA, such as Deep Q-Network (DQN), Proximal Policy Optimization (PPO), and Multi-Agent Reinforcement Learning (MARL). It also highlights how these technologies address critical challenges in SCA, including dynamic obstacle avoidance, compliance with Convention on the International Regulations for Preventing Collisions at Sea (COLREGs), and coordination in dense traffic scenarios, while underscoring persistent limitations such as idealized assumptions, scalability issues, and robustness in uncertain environments. Contributions include a structured analysis of recent technological evolution, and a Large Language Model (LLM) based hierarchical architecture integrating perception, communication, decision-making, and execution layers for future SCA systems, which prioritizes the development of scalable, adaptive frameworks that ensure robust and compliant autonomous navigation in complex, real-world maritime environments.
Ship manoeuvring model identification using mutual information clustering with stepwise regression structural optimisation under small-sample constraints

Xiufeng Zhang, Rui Tian, Haitong Xu, and 2 more authors

Ocean EngineeringMore Information can be found here , 2025

Cited by:

Abs DOI HTML PDF Video

This paper proposes a novel modelling approach, Mutual Information Clustering with Stepwise Regression, to address parameter drift caused by multicollinearity among hydrodynamic terms, which often occurs in model identification methods of ship manoeuvring that primarily depend on long-term training data. The proposed method initially clusters highly correlated hydrodynamic terms using mutual information and subsequently employs stepwise regression to identify those terms that significantly influence the output response. Validation is conducted utilizing the sea trial data from the full-scale YUKUN vessel, and the prediction performance is compared with the Abkowitz model, the manoeuvring model group model, and a conventional mutual information-based feature selection algorithm. The results indicate that the proposed algorithm effectively diminished hydrodynamic parameter drift, particularly when trained on small-sample datasets.
Multi-step online prediction of 4 degrees of freedom motion under various wind scales based on pre-training strategy and ensemble learning framework

Yao Meng, Xianku Zhang, Xiufeng Zhang, and 3 more authors

Ocean EngineeringMore Information can be found here , 2025

Cited by:

Abs DOI HTML PDF Video

Accurate multi-step prediction enhances navigational safety and optimises the performance of autonomous control systems. Given the limitations of single data-driven models and single-step prediction schemes, this paper proposes a multi-step online motion prediction scheme based on the weighted multi-kernel relevance vector machine, pre-training strategy, and ensemble learning framework. To evaluate the effectiveness and generalisation of the proposed scheme, four degrees of freedom motion data are collected under various wind conditions. A subset of motion data is used as training samples to pre-train three sub-models, whose parameters are tuned using an improved grey wolf optimiser algorithm. To integrate the prediction results of the sub-models, this paper develops an ensemble learning framework and proposes an adaptive weight updating rule. Then, this paper conducts single-step, 5-step, and 10-step time series predictions of ship motion. The comparison results with long short-term memory method confirm the adaptability and generalisation of the proposed scheme. The final experimental results show that the proposed scheme maintains good generalisation and time efficiency while ensuring low model complexity. The mean squared errors of the single-step and multi-step prediction results are below 8×10−3 and 0.28. This method can provide a reliable nonparametric identification modelling scheme for USVs.
Unsupervised deep image stitching based on cascaded warping and multi-scale seam prediction for USV wide field-of-view generation

Zhilin Yang, Yong Yin, Qianfeng Jing, and 3 more authors

Autonomous Transportation ResearchMore Information can be found here , 2025

Cited by:

Abs DOI HTML PDF Video

This study proposes an unsupervised deep image stitching method based on cascaded warping and multi-scale seam prediction to address the challenges of low texture and large parallax image stitching for maritime scenes. In the image alignment stage, convolutional and transformer architectures are integrated to enhance multi-scale feature modelling in low-texture scenes, achieving high-precision alignment through a three-stage cascaded process of global homography and thin-plate spline (TPS) transformations. In the image composition stage, a decoupled multi-scale seam prediction approach is introduced, effectively mitigating artefacts by fusing multi-resolution soft-encoded seam masks. Experimental tests are conducted on a self-constructed maritime image stitching dataset (MISD) covering diverse textures, parallax, and illumination conditions. Results demonstrate that the proposed method outperforms traditional and deep learning approaches in terms of alignment accuracy and seam quality while maintaining low computational complexity, achieving an effective balance between precision and efficiency. This study presents a robust and efficient solution for wide field-of-view generation in unmanned surface vehicles (USVs), significantly enhancing the perception range of maritime intelligent transportation systems and laying a foundation for multi-view video stitching.
Offline Prediction of 3 DOF Ship Motions Based on Relevance Vector Machine and Free-running Test Data with Noise

Yao Meng, Xianku Zhang, Haitong Xu, and 1 more author

IFAC-PapersOnLineMore Information can be found here , 2025

Cited by:

Abs DOI HTML PDF Video

To improve the computational efficiency and accuracy of ship motion prediction, this paper uses a sparse relevance vector machine to predict the three degrees of freedom motions of a free-running container ship model. Zigzag test data under different rudder angles, collected from the Oceanic pool in Oeiras, Portugal, is used in this paper, including environmental disturbances and instrument noise. The test data are then preprocessed and divided into training and test samples. Based on the processed data, the non-parametric model and the proposed algorithm, the surge velocity, sway velocity and yaw rate are predicted. Finally, the prediction results of the proposed scheme are compared with those obtained by long short-term memory to verify the effectiveness and generalization of the proposed scheme. The verification results show that the proposed scheme is superior to the long short-term memory in prediction accuracy. The average absolute error of the prediction results is less than 0.53. This research result can provide an efficient and reliable scheme for ship maneuverability prediction.
Path following control for an underactuated autonomous ship model using an L1 adaptive controller

Haitong Xu and C. Guedes Soares

IFAC-PapersOnLineMore Information can be found here , 2025

Cited by:

Abs DOI HTML PDF Video

This paper proposes an L1 adaptive backstepping control strategy integrated with a vector field-based guidance method to steer an underactuated autonomous marine vessel along a predefined trajectory, utilizing a nonlinear heading dynamics model. The controller is rigorously designed within a Lyapunov-based stability framework, ensuring convergence and system robustness. The L1 approach offers a promising balance between robustness and rapid adaptation to system uncertainties. To validate the proposed approach, numerical experiments are performed using a comprehensive nonlinear maneuvering model of an underactuated tanker subjected to random ocean current disturbances. This maneuvering model, developed based on free-running experimental data, serves as a reliable platform for assessing the controller’s practical viability. A simulation-based path following test demonstrates the performance and efficiency of the proposed control algorithm and guidance strategy.
Ship Formation Control Using Nonlinear Model Predictive Control With Safe Speed Constraints and Tidal Elevation Variations

Fanglie Wu, Xin Su, Tingting Cheng, and 2 more authors

2025

Cited by: 0; All Open Access, Gold Open Access

Abs DOI

To improve transportation efficiency, an adaptive speed control method is proposed for ship formation control when a ship formation enters a port with tidal elevation variations. The nonlinear model predictive control (NMPC) method and leader‒follower structure are utilised for the formation keeping and trajectory tracking tasks. The proposed method establishes a ship manoeuvring model and a dynamic speed constraint model for adaptive speed control. A safe distance model is constructed to maintain a safe distance between ship formation members. The proposed safe distance model utilises a Serret‒Frenet (S‒F) coordinate system to describe the positions of ship formation members. Simulation experiments are applied to the North Channel of the Yangtze River. The experimental results indicate that the maximum actual draught accounts for 101.4% of the maximum safe draught without speed constraints. The draft ratio decreases to 99.2% after the adaptive speed control method is applied. This method can be utilised to effectively control ship formation navigation considering variations in tidal elevation. © 2025 The Author(s). IET Intelligent Transport Systems published by John Wiley & Sons Ltd on behalf of The Institution of Engineering and Technology.
Impact of a tri-dimensional conical structure made of composite materials

M. Calvário, Xu Haitong, S. Wang, and 2 more authors

2025

Cited by: 0

Abs DOI

This paper investigates the impact strength of a three-dimensional conical structure constructed from composite materials, focusing on its application in wave energy converters. Two glass fibre-reinforced polymers, unidirectional and bi-axial stitched fabrics, are analysed. The study includes an experimental low-velocity impact of plates with solid objects, simulating low-velocity impact with floating debris, and an experimental bottom wave slamming test where the structure is dropped from a height of 1.5 m onto a calm water surface equivalent to an initial velocity of 5.43 (m/s). In addition, a destructive buckling test is carried out by applying pressure to the conical to assess the buckling strength of both laminates. Furthermore, the experimental buckling pressure failure is compared with the pressure peak determined by a numerical simulation, based on the Arbitrary Lagrangian Eulerian formulation, and with a design pressure suggested by a classification society recommended practice. Results demonstrate that the biaxial stitched fabric reveals a higher impact strength on both impacts with solids and fluids and a higher buckling strength. Moreover, the peak pressure determined by the numerical simulation is slightly higher than that a conservative design approach predicted. © 2024
Integration Adaptive Unscented Kalman Filter and Nonlinear Model Predictive Control for Towing System Under Environmental Disturbances

Zihao Lin, Bing Wu, Li Tang, and 3 more authors

2025

Cited by: 0; Conference name: 8th International Conference on Transportation Information and Safety, ICTIS 2025; Conference date: 16 July 2025 through 19 July 2025; Conference code: 214490

Abs DOI

With the rapid advancement of intelligent technologies, the demand for tugboats capable of handling complex towing operations has increased. However, environmental disturbances present significant challenges to the stability and precision of towing systems. This study presents a control approach integrating Adaptive Unscented Kalman Filtering (AUKF) with Nonlinear Model Predictive Control (NMPC). The proposed method enables two tugboats to collaboratively tow a ship along a desired trajectory while mitigating the effects of disturbances. The ship controller minimizes trajectory deviations while ensuring compliance with system constraints. To enhance robustness, the AUKF dynamically updates noise covariance matrices based on state covariance and observation errors, providing accurate state estimates for the ship controller, which then computes the desired positions for the tugboats. Simulation results demonstrate that the proposed method improves trajectory tracking accuracy and system robustness under disturbed conditions. © 2025 IEEE.
An Efficient Laser Point Cloud Registration Method for Autonomous Surface Vehicle

Dongdong Guo, Qianfeng Jing, Yong Yin, and 1 more author

2025

Cited by: 2; All Open Access, Gold Open Access

Abs DOI

In the field of Autonomous Surface Vehicle (ASV), research on advanced perception technologies is crucial for enhancing their intelligence and autonomy. In particular, laser point cloud registration technology serves as a foundation for improving the navigation accuracy and environmental awareness of ASV in complex environments. To address the issues of low computational efficiency, insufficient robustness, and incompatibility with low-power devices in laser point cloud registration technology for ASV, a novel point cloud matching method has been proposed. The proposed method includes laser point cloud data processing, feature extraction based on an improved Fast Point Feature Histogram (FPFH), followed by a two-step registration process using SAC-IA (Sample Consensus Initial Alignment) and Small_GICP (Small Generalized Iterative Closest Point). Registration experiments conducted on the KITTI benchmark dataset and the Pohang Canal dataset demonstrate that the relative translation error (RTE) of the proposed method is 16.41 cm, which is comparable to the performance of current state-of-the-art point cloud registration algorithms. Furthermore, deployment experiments on multiple low-power computing devices showcase the performance of the proposed method under low computational capabilities, providing reference metrics for engineering applications in the field of autonomous navigation and perception research for ASV. © 2025 by the authors.
Automatic Fault Diagnosis of Diesel Fuel System Based on Wavelet Analysis and SOM-BP Neural Network

Yu Xing, Yuanbin Liu, Haoran Ye, and 1 more author

2025

Cited by: 0; Conference name: International Conference on Artificial Intelligence and Autonomous Transportation, AIAT 2024; Conference date: 6 December 2024 through 8 December 2024; Conference code: 328519

Abs DOI

The diesel fuel system is critical to the functioning of diesel engines, and its failure can result in significant economic losses and operational risks. This paper presents a fault diagnosis method that integrates wavelet analysis with a neural network for managing the health of diesel engine fuel systems. First, the oil pressure waveform of a diesel engine’s high-pressure oil pipe is collected using an external clamp-on pressure sensor. Wavelet threshold denoising is then applied to eliminate noise from the oil pressure signal. Next, characteristic parameters of the oil pressure waveform, such as waveform width, amplitude, and maximum pressure, are extracted, and wavelet packet band analysis is employed to decompose and analyse the signal. These extracted parameters serve as input vectors for a neural network. A combined self-organizing mapping back propagation (SOM-BP) neural network model is developed to diagnose fuel system faults. Experimental results demonstrate that this model significantly enhances diagnostic accuracy and can effectively identify various fault types. © Beijing Paike Culture Commu. Co., Ltd. 2025.
Cooperative path following control of USV-UAVs with genetic algorithm extended state observer

Hugan Zhang, Xianku Zhang, Xu Haitong, and 1 more author

2025

Cited by: 19

Abs DOI

This work investigates an innovative decentralized formation control method for underactuated surface vessel (USV) and underactuated aerial vehicles (UAVs) to achieve path following in the presence of external disturbances. The design of the USV-UAVs cooperative path following controller is divided mainly into two parts. The first part is the guidance system,which employs a line of sight (LOS) based on a switching mechanism for selecting the next way point to steer the USV in path following, thereby mitigating overshooting at turning points. For UAVs, the virtual attitude angles are designed to guide UAVs in tracking the USV’s trajectory. The second part is the control system, which uses sliding mode to design a controller to enable the USV-UAVs to track the reference path. An extended state observer,the genetic algorithm-based extended state observer (GAESO), is proposed to estimate unmodeled dynamics and external disturbances. The stability proof of both the USVs and UAVs is presented using the Lyapunov theorem. Finally, the simulation tests are carried out to validate the proposed system and control methods in the presence of environmental disturbance. © 2025
Review of System Identification for Manoeuvring Modelling of Marine Surface Ships

Haitong Xu and C. Guedes Soares

2025

Cited by: 3; All Open Access, Hybrid Gold Open Access

Abs DOI

A state-of-the-art review is presented of mathematical manoeuvring models for surface ships and parameter estimation methods that have been used to build mathematical manoeuvring models for surface ships. In the first part, the classical manoeuvring models, such as the Abkowitz model, MMG, Nomoto and their revised versions, are revisited and the model structure with the hydrodynamic coefficients is also presented. Then, manoeuvring tests, including both the scaled model tests and sea trials, are introduced with the fact that the test data is critically important to obtain reliable results using parameter estimation methods. In the last part, selected papers published in journals and international conferences are reviewed and the statistical analysis of the manoeuvring models, test data, system identification methods and environmental disturbances used in the paper is presented. © The Author(s) 2025.
Advancements of Image and Video Stitching Techniques: A Review

Zhilin Yang, Yong Yin, Haitong Xu, and 4 more authors

2025

Cited by: 3

Abs DOI

Image and video stitching techniques represent a significant research direction in the field of computer vision. They aim to generate images or videos with a wide field of view from multiple overlapping images or videos. These techniques find widespread application in virtual reality, autonomous driving, surveillance systems, digital cultural heritage preservation, and other fields. However, image and video stitching still encounter challenges, including large parallax, occlusion, weak texture, shape distortion, video jitter, and low efficiency. In recent years, these challenges have spurred the development of various new image and video stitching techniques. This work offers a comprehensive review of the latest advancements in image and video stitching techniques. First, we analyze traditional stitching methods and deep learning-based methods, discussing key techniques such as shape correction in image stitching and video stabilization. Second, we review datasets and evaluation metrics for image and video stitching tasks and analyze the performance of mainstream algorithms on representative datasets. Finally, we discuss typical application scenarios and future research directions for image and video stitching. This work aims to provide researchers with a detailed overview of advancements in image and video stitching techniques and to inspire improved stitching methods, thereby advancing the development of image and video stitching. © 2001-2012 IEEE.
Online non-parametric 4 DOF modelling of ship motion using hybrid kernel relevance vector machine

Yao Meng, Xianku Zhang, Xiufeng Zhang, and 2 more authors

2025

Cited by: 1

Abs DOI

The complex characteristics of ship motion under various manoeuvres and environmental conditions are determined online by a non-parametric identification model. This paper introduces a novel online ship motion modelling method that adaptively adjusts the training samples based on a sparse hybrid kernel relevance vector machine. Firstly, to fully capture the motion characteristics of the ship, the manoeuvrability test data is collected from a marine manoeuvring simulator, including different operators, engine orders, rudder angles and environments. Additionally, full-scale sea trial data is obtained from the YUKUN vessel, a ship type different from the virtual ship in the simulator. Subsequently, an adaptive criterion for updating the training sample is developed, and a sliding time window is applied to dynamically update the ship motion data. Finally, the motion states and trajectories of both ships are predicted under different conditions. These results show that the proposed method is well-suited for online non-parametric modelling of different ships and manoeuvre conditions. The proposed scheme’s mean squared error and mean absolute error are below 0.10 and 0.16. Compared with the non-adaptive online scheme, the proposed approach has stronger generalisation and adaptability. This scheme can serve as a reference for online non-parametric modelling of unmanned surface vehicles. © 2025

2024

Hybrid path planning method for USV using bidirectional A* and improved DWA considering the manoeuvrability and COLREGs

Donghao Xu, Jie Yang, Xueqian Zhou, and 1 more author

More Information can be found here , 2024

Cited by: 60; All Open Access, Hybrid Gold Open Access

Abs DOI HTML PDF Video

This paper proposes a hybrid dynamic path planning algorithm that integrates global path planning (GPP) and local path planning (LPP). The objective is to effectively address the challenges associated with path planning and collision avoidance for unmanned surface vehicles (USV) in complex environments. The bidirectional A* algorithm is used to search the optimized strategy based on the actual geographical information map for the navigation routes of USV. The Dynamic Window Algorithm (DWA) is employed, and a novel cost function is formulated considering the USV’s manoeuvring characteristics, dynamic constraints, and environmental information. The primary purpose is to ensure the compliance of the USV with COLREGs during dynamic obstacle avoidance. It accomplishes this by providing positive reinforcement for achieving the correct turning speed when the USV determines the orientation of an approaching ship. Another evaluation function is introduced to mitigate the problem of local optima in complex environments that the LPP may encounter. The actual work map is used to model the application scenario with the obstacles in the presence of incoming ships, the simulation results show that the proposed algorithm is capable of generating adaptive, collision-free routes while adhering to COLREGs rules. © 2024 The Authors
Optimal Path Following Controller Design Based on Linear Quadratic Regulator for Underactuated Ships in Varying Wave and Wind Conditions

Abbas Ghassemzadeh, Haitong Xu, and C. Guedes Soares

2024

Cited by: 2

Abs DOI

This study presents an optimisation-based approach for determining controller gains in ship path-following under varying sea states, wave, and wind directions. The dynamic Line of Sight approach is used to regulate the rudder angle and guide the Esso Osaka ship along the desired path. Gains are optimised using a genetic algorithm and a comprehensive cost function. The analysis covers a range of wave attack directions and sea states to evaluate the controller performance. Results demonstrate effective convergence to the desired path, although a steady-state error persists. Heading and rudder angle performance analyses show successful convergence and dynamic adjustments of the rudder angle to compensate for deviations. The findings underscore the influence of wave and wind conditions on ship performance and highlight the need for precise gain tuning. This research contributes insights into optimising and evaluating path-following controllers for ship navigation. © Harbin Engineering University and Springer-Verlag GmbH Germany, part of Springer Nature 2024.
Heterogeneous cooperative trajectory tracking control between surface and underwater unmanned vehicles

Hugan Zhang, Xianku Zhang, Haitong Xu, and 1 more author

2024

Cited by: 30; All Open Access, Hybrid Gold Open Access

Abs DOI

This paper introduces a decentralized control strategy for a heterogeneous team consisting of an unmanned surface vessel serving as the leader vehicle and two unmanned underwater vessels acting as follower vehicles. The team is designed to work together to accomplish underwater exploration missions. The communication network of the team is a fixed, directed topology and only the follower unmanned underwater vessels can read the states of the leader unmanned surface vessel. The proposed system consists of a guidance loop and a control loop. In the guidance loop, a novel cooperative guidance method between a surface and two underwater unmanned vessels is introduced by constructing a path deviation based on vertical line constructs. In the control loop, an iterative sliding mode controller is designed to mitigate chattering issues caused by switching system structures. Meanwhile, an optimization function is employed to optimize control inputs, addressing control input constraints, and reducing control input chattering. The external disturbances and unmodeled dynamics are estimated using a linear extended state observer, and the results are used for the controller design. Finally, simulation tests are carried out to validate the effectiveness of the proposed control system. © 2024 The Authors
Maritime Autonomous Surface Ships

Haitong Xu, Lúcia Moreira, Xianbo Xiang, and 1 more author

2024

Cited by: 0; All Open Access, Gold Open Access

DOI
Path following control of underactuated unmanned surface vessel using virtual circle guidance method

H.G. Zhang, J.M. Fan, X.K. Zhang, and 2 more authors

2024

Cited by: 0

Abs DOI

Underactuated unmanned surface vessels face challenges related to external environmental disturbances, uncertainties in the internal model, and the occurrence of overshooting during waypoint navigation. In order to address the aforementioned issues, this paper proposes a path-following control strategy based on a virtual circle guidance method. Firstly, by constructing a virtual heading, the following of waypoints are transformed into the control of the virtual heading. A sliding mode controller is employed to control the heading of the underactuated unmanned surface vessel. To reduce overshooting during the following of waypoints, a variable virtual circle is constructed based on the angle between the connecting lines of waypoints. A linear extended state observer is designed to estimate external disturbances and unmodeled dynamics, and the estimated disturbances are compensated in the controller design to enhance the robustness of the system. Finally, the effectiveness of the proposed algorithm is validated using simulation tests. © 2024 selection and editorial matter, Carlos Guedes Soares and Tiago A. Santos; individual chapters, the contributors.
Dynamic evolution of ship state prediction using adaptive unscented Kalman filtering in zigzag manoeuvring tests

A. Ghassemzadeh, Xu Haitong, and C. Guedes Soares

2024

Cited by: 0

Abs DOI

This paper explores ship state prediction during zigzag manoeuvres using the Unscented Kalman Filter. To address uncertainties, it introduces the Adaptive Unscented Kalman Filter, emphasizing covariance matching. The evaluation compares conventional Unscented Kalman Filter and Adaptive Unscented Kalman Filter, highlighting Adaptive Unscented Kalman Filter’s superior accuracy in state estimation.The analysis extends to the adaptive algorithm’s dynamic behavior, revealing a gradual evolution of error covariance over time.The covariance converges to a constant value after around 200 iterations, revealing a critical nuance in the system’s uncertainty dynamic. Moreover, the limitations of relying solely on prior estimations based on sensor specifications are underscored. The study suggests adapting filtering algorithms for evolving uncertainty in ship dynamic, emphasizing continuous refinement for accurate state estimations in dynamic maritime environments, especially through the use of the Unscented Kalman Filter. © 2024 selection and editorial matter, Carlos Guedes Soares and Tiago A. Santos; individual chapters, the contributors.
Wave energy converter power take-off with active oil-hydraulic accumulator

J.F. Gaspar, C. Zeng, Xu Haitong, and 3 more authors

2024

Cited by: 0

Abs DOI

A new concept of an oil-hydraulic accumulator is proposed in this work to improve the harvesting performance of wave energy converters. The oil-hydraulic power take-off converts the reciprocating motion of the wave energy converter prime mover into the rotation of the generator shaft. Oil-hydraulic power take-offs integrated with accumulators are commonly classified as constant-pressure type. Conventional accumulators reduce the pressure fluctuation in the hydraulic systems but also impose limitations on the adaptability of the power take-offs to different sea states. This accumulator consists of two standard accumulators whose gas chambers are interconnected so that the charging characteristics of the accumulator can be adjusted by compressing or decompressing the gas in the shared chambers. Thus, compared to the conventional power take-offs, the power take-off integrated with the active accumulator system can be actively adapted to different sea states and ultimately improve the harvesting performance of the wave energy converter. The work focuses on the numerical implementation of the concept and the results indicate the accumulator concept brings significant advantages compared to the conventional in terms of better power output over a wide range of sea states. © 2024 selection and editorial matter, Carlos Guedes Soares and Tiago A. Santos; individual chapters, the contributors.
Effect of Sampling Rate in Sea Trial Tests on the Estimation of Hydrodynamic Parameters for a Nonlinear Ship Manoeuvring Model

Haitong Xu, P. Silva, and C. Guedes Soares

2024

Cited by: 9; All Open Access, Gold Open Access

Abs DOI

This paper explores the impact of sampling rates during sea trials on the estimation of hydrodynamic parameters in a nonlinear manoeuvring model. Sea trials were carried out using an offshore patrol vessel and test data were collected. A nonlinear manoeuvring model is introduced to characterise the ship’s manoeuvring motion, and the truncated least squares support vector machine is employed to estimate nondimensional hydrodynamic coefficients and their corresponding uncertainties using the 25°–25° zigzag test. To assess the influence of the sampling rates, the training set is resampled offline with 14 sampling rates, ranging from 0.2 Hz to 5 Hz, encompassing a rate 10 times the highest frequency component of the signal of interest. The results show that the higher sampling rate can significantly diminish the parameter uncertainty. To obtain a robust estimation of linear and nonlinear hydrodynamic coefficients, the sampling rate should be higher than 10 times the highest frequency component of the signal of interest, and 3–5 Hz is recommended for the case in this paper. The validation is also carried out, which indicates that the proposed truncated least square support vector machine can provide a robust parameter estimation. © 2024 by the authors.
Unmanned Surface Vessel–Unmanned Aerial Vehicle Cooperative Path Following Based on a Predictive Line of Sight Guidance Law

Hugan Zhang, Jiaming Fan, Xianku Zhang, and 2 more authors

2024

Cited by: 6; All Open Access, Gold Open Access

Abs DOI

This paper explores the cooperative control of unmanned surface vessels (USVs) and unmanned aerial vehicles (UAVs) in maritime rescue and coastal surveillance. The USV-UAV system faces challenges of disturbances and substantial inertia-induced overshooting during path following. A novel position prediction line of sight (LOS) guidance law is proposed to address these issues for USV path following control. Radial basis function-based neural networks (RBF-NNs) are used to estimate disturbances, and a high-order differentiator is used to design a velocity observer for unknown USV velocity. The UAV control system employs proportional–derivative (PD) control with feedforward compensation for quadrotor control design and utilizes a finite-time converging third-order differentiator to differentiate non-continuous functions. The simulation results demonstrate strong robustness in the proposed USV-UAV cooperative control algorithm. It achieves path following control in the presence of wind and wave disturbances and exhibits minimal overshoot. © 2024 by the authors.

2023

Data-Driven Parameter Estimation of Nonlinear Ship Manoeuvring Model in Shallow Water Using Truncated Least Squares Support Vector Machines

Haitong Xu and C. Guedes Soares

2023

Cited by: 3; All Open Access, Gold Open Access, Green Open Access

Abs DOI

A data-driven method, the truncated LS-SVM, is proposed for estimating the nondimensional hydrodynamic coefficients of a nonlinear manoeuvring model. Experimental data collected in a shallow water towing tank are utilized in this study. To assess the accuracy and robustness of the truncated LS-SVM method, different test data sizes are selected as the training set. The identified nondimensional hydrodynamic coefficients are presented, as well as the corresponding parameter uncertainty and confidence intervals. The validation is carried out using the reference data, and statistical measures, such as the correlation coefficient, centred RMS difference, and standard deviation are employed to quantify the similarity. The results demonstrate that the truncated LS-SVM method effectively models the hydrodynamic force prediction problems with a large training set, reducing parameter uncertainty and yielding more convincing results. © 2023 by the authors.
Review of Path-following Control Systems for Maritime Autonomous Surface Ships; [海上自主水面船舶(MASS)路径跟踪控制系统综述]

Haitong Xu and C. Guedes Soares

2023

Cited by: 14; All Open Access, Hybrid Gold Open Access

Abs DOI

A review presents the state-of-the-art path-following control systems for maritime autonomous surface ships, where the special focus is placed on the guidance subsystem and control subsystem. The path following control system is one of the basic requirements for autonomous ships since it guarantees that the ship can track the predefined path with small cross-track errors. The path following problem is firstly defined, and the cross-track error dynamics are derived from the kinematic equations of marine surface ships. The classical guidance laws are introduced, and the governing equations are also presented in this paper. A review of the guidance laws and controllers for the maritime autonomous surface ships has been carried out based on relevant journal and conference papers. Several important properties and characteristics, such as control structure, guidance law, control method, stability, environmental disturbance and vessel dynamics, are defined for the comparative analysis. Finally, the summary and a discussion on the most used technologies for the path following control of marine autonomous surface ships are presented and highlighted. © 2023, The Author(s).
Maritime Autonomous Vessels

Haitong Xu, Lúcia Moreira, and C. Guedes Soares

2023

Cited by: 14; All Open Access, Gold Open Access, Green Open Access

DOI
Path following control using robust sliding mode for an autonomous surface vessel based on ε- support vector regression identified steering model

Abbas Ghassemzadeh, Haitong Xu, and C. Guedes Soares

2023

Cited by: 5; All Open Access, Hybrid Gold Open Access

Abs DOI

Due to the complexity and unmodeled dynamics along with internal model uncertainties, an ε- Support Vector Regression (SVR) algorithm is implemented to determine the parameters of Nomoto’s steering equation of an Autonomous Surface Vessel (ASV) based on the experimental data for 20°−20° zigzag manoeuver. An analytical formulation is used to compare and check the accuracy of the system identification method. Then, considering the uncertainty in estimated parameters, a sliding mode controller for the path following control is implemented with −20%,0%, and 20% uncertainty in the obtained coefficients, (K, T). To follow the desired path, the Dynamic Line of Sight algorithm is proposed and its parameters are obtained based on the optimal performance of the ASV in converging to the desired path. The results demonstrate that theε-SVR can adequately estimate the hydrodynamic coefficients using free-running model tests. Similarly, the designed controller also showed that ASV followed the predefined path with an average following error of 9.5%. The simulation results considering the bounded of 20% uncertainty in hydrodynamic parameters also show that the uncertainty effects are less on the path following control (average of −9.9% in −20% and 2.8% in +20% uncertainty) and not made instability in the designed controller. © 2023 The Author(s)
Experimental study on the mooring forces and motions of a fish cage under regular waves

Zhongchi Liu, Haitong Xu, and C. Guedes Soares

2023

Cited by: 29; All Open Access, Hybrid Gold Open Access

Abs DOI

Experiments are conducted in a flume to study the mooring forces and motions of a gravity cage in regular waves. Cage models are built with hollow pipes and nets. Mooring forces and cage motions including surge, heave and pitch are measured. With the increase of the wavelength, the mooring force, surge and heave increase while the rate of increase gradually slows down until stops. On the other hand, under short waves, the pitch increases with the decrease of the wavelength. In addition, the cage does not finish a cycle of motion before the next peak arrives, which leads to a reduction in mooring forces and motion in all directions. With the observation of overtopping, it can be concluded that the motion of the cage goes through three phases with the growth of the wavelength. Under short waves, the cage does not have enough time to complete a cycle of motion and overtopping occurs. With the increase of the wavelength, the motion of the cage starts to follow the waves and overtopping disappears. When the wave is long enough, the cage is pulled into the water by the mooring line and overtopping occurs again. © 2023 The Authors
Path following control for large inland ships in a restricted waterway using the nonlinear terminal sliding mode method

Donghao Xu, Yijian Huang, Xueqian Zhou, and 1 more author

2023

Cited by: 14

Abs DOI

In order to solve the problem of path following for large ships travelling in restricted waterways, an adaptive Line-Of-Sight (LOS) guidance with the Nonlinear Terminal Sliding Mode (NTSM) algorithm is proposed in this paper. Compared to classical Sliding Mode Controller (SMC) and Adaptive Sliding Mode Controller (ASMC), the proposed system enables large ships to track the desired path much faster, meanwhile, the course stability can also be achieved with the controller saturation and environmental disturbance. To solve the problems of high nonlinearity and uncertainty of ship motion in restricted waters, the mathematical model with Extended state observer (ESO) is proposed to linearize problem. A drift angle observer is established to observe the drift angle during the vessel’s navigation, and the LOS guidance law is used to achieve accurate tracking of the desired trajectory. The simulation results show that the inland ships under the control of the proposed scheme can accurately track the desired trajectory in a restricted waterway. The proposed algorithm has good robustness under the effect of environmental disturbances. © 2023
Fixed-time leader-follower formation control of underactuated unmanned surface vehicles with unknown dynamics and ocean disturbances

Chenfeng Huang, Haitong Xu, P. Batista, and 2 more authors

2023

Cited by: 52

Abs DOI

This paper investigates the formation control problem of underactuated unmanned surface vehicles with unknown dynamics and ocean disturbances. To tackle the leader-follower configuration, an improved fixed-time velocity controller is proposed for the virtual vehicle to guide the followers efficiently. For the tracking control of the follower vehicles, a concise controller is designed by borrowing on backstepping and nonsingular sliding mode control techniques. A novel adaptive filter is developed to address the so called “explosion of complexity” problem in the traditional backstepping framework, which could simplify the control structure and facilitate the implementation of the proposed controller in practical engineering. Furthermore, the radial basis function neural network is employed to identify the unknown dynamics of the vehicle model. A bounded-feedback adaptive law is developed to estimate the upper bound of the ocean disturbances. That could greatly enhance the robustness and accuracy of the controller. Finally, a rigorous proof has been given to guarantee the practical fixed-time stability of the closed-loop system. Two examples are provided to demonstrate the effectiveness and superiority of the theoretical results. © 2023

2022

Adaptive nonlinear vessel steering modelling using time-sequence incremental and decremental LS-SVM

Xu Haitong and C. Guedes Soares

2022

Cited by: 0

Abs DOI

In this paper, an adaptive nonlinear vessel steering model is proposed. A time-sequence Least square support vector machine (LS-SVM) based on incremental and decremental updating algorithm is proposed to estimate the parameters dynamically. The proposed method is different from the online estimations method based on a sliding data window, which usually needs to train the model when a new sample is observed during each time step. It usually indicates an expensive and time-costing operation for training SVM. In the presented method, the parameters can update in an incremental and decremental way, which avoid the training operation. The validation is carried out based on the manoeuvring tests using a free-running ship model. The obtained parameters agree well with the analytical values. The effect of the length of the training set is also discussed. The size of training set plays a trade-off on the stable and response speed of the system. The proposed method can dynamically estimate the parameters with a good accuracy and fast response. It can be used for designing a dynamic model-based control system for vehicles. © 2022 the Author(s).
Convergence analysis of hydrodynamic coefficients estimation using regularization filter functions on free-running ship model tests with noise

Haitong Xu and C. Guedes Soares

2022

Cited by: 15

Abs DOI

This paper introduces an effective method with a regularization filter function and conducts stability and convergence analysis for the estimation of the hydrodynamic coefficients of a manoeuvring model. The proposed method is used to estimate the adjustment coefficients of empirical manoeuvring models using free-running manoeuvring ship model tests. The method avoids the recurrent difficulty that parameter estimation based on test data are usually ill-conditioned, and the obtained parameters are unstable and sensitive to noise. The model tests are carried out using a free-running scaled container ship, and the data acquisition and control system is implemented in the LabVIEW platform. Then, the obtained data are used for the parameter estimation using the proposed method and the optimal regularization factor is discussed. Validation is carried out and shows the effectiveness of the proposed method. © 2022 Elsevier Ltd

2021

L1 adaptive backstepping control for path-following of underactuated marine surface ships

Haitong Xu, P. Oliveira, and C. Guedes Soares

2021

Cited by: 67

Abs DOI

A L1 adaptive backstepping controller is proposed for path-following control of an underactuated ship based on a nonlinear steering model, and the control law is derived using Lypunov control function. L1 adaptive controller is a novel technology considering both the robustness and fast adaptation. The closed-loop control system is proved to be uniformly global asymptotically stable. A novel guidance law, time-varying vector field, is proposed for the guidance system. The kinematic analysis of path-following shows that the guidance and control systems are coupled, and the guidance system is affected by the performance of the controller. The Lyapunov method is employed to show that the equilibrium point of the whole system is uniformly global asymptotically stable. Path-following simulations are carried out to validate the performance of the proposed control law and vector field guidance law using a fully nonlinear manoeuvring mode of an underactuated tanker in the presence of stochastic ocean current. © 2020 European Control Association
Motion planning, guidance, and control system for autonomous surface vessel

M.A. Hinostroza, Haitong Xu, and C. Guedes Soares

2021

Cited by: 16

Abs DOI

This paper presents a motion planning, guidance, and control system for an autonomous surface vessel in a practical maritime environment. The motion planning algorithm is based on the angle-guidance fast-marching square method (AFMS), and the guidance system is based on the line-of-sight (LOS) trajectory tracking algorithm. To validate the motion planning algorithm, numerical simulations were carried out to compute the optimal path in a static environment including various obstacles. The guidance and control system were tested with an autonomous surface vehicle (ASV) tracking a pre-established trajectory including static obstacles. The autonomous surface vehicle is a self-propelled scaled ship model of 2.5 m equipped with sensors and actuators, inertial measurement unit (IMU), global positioning system (GPS), propulsion direct current (DC) motors, and wireless communication. From the experiments and numerical simulations, a good agreement was found. Copyright © 2020 by ASME.
Experimental results of the cooperative operation of autonomous surface vehicles navigating in complex marine environment

M.A. Hinostroza, Haitong Xu, and C. Guedes Soares

2021

Cited by: 23; All Open Access

Abs DOI

Experimental results are presented of the cooperative operation of two maritime autonomous surface vehicles (ASVs) executing a pre-defined task in a complex marine environment. The ASVs are equipped with algorithms for motion-planning, path-following and motion control, where the motion-planning algorithm is based in the angle-guidance fast marching square method, the path-planning module is based in the vector-field path-following method and the controller is a PID. The ASVs are two self-propelled models of 2.5 m and 3.2 m length instrumented with several sensors, actuators and communication unit, such as, inertial measurement units, Global positioning system, anemometers, accelerometers, inclinometers, DC motors and Wi-Fi communication. To monitor and command the ASVs, a real-time program was coded in LabVIEW 2018®. Finally, in order to validate the developed system, experimental tests were carried out in an open-door pool with low wind conditions, and from these experiments good capabilities of the system were found. © 2020 Elsevier Ltd
Modified vector field path-following control system for an underactuated autonomous surface ship model in the presence of static obstacles

Haitong Xu, Miguel A. Hinostroza, and C. Guedes Soares

2021

Cited by: 31; All Open Access, Gold Open Access, Green Open Access

Abs DOI

A modified path-following control system using the vector field method for an underactuated autonomous surface ship model is proposed in the presence of static obstacles. With this integrated system, autonomous ships are capable of following the predefined path, while avoiding the obstacles automatically. It is different from the methods in most published papers, which usually study path-following and obstacle collision avoidance, separately. This paper considers the coupled path following and collision avoidance task as a whole. Meanwhile, the paper also shows the heading control design method in the presence of static obstacles. To obtain a strong stability property, a nonlinear autopilot is designed based on the manoeuvring tests of the free-running ship model. The equilibrium point of the controller is globally exponentially stable. For the guidance system, a novel vector field method was proposed, and the proof shows the coupled guidance and control system is uniform semi-global exponentially stable (USGES). To prevent the obstacles near the predefined path, the proposed guidance law is augmented by integrating the repelling field of obstacles so that it can control the ship travel toward the predefined path through the obstacles safely. The repelling field function is given considering the obstacle shape and collision risk using the velocity obstacle (VO) algorithm. The simulations and ship model test were performed to validate the integrated system of autonomous ships. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Robust Parameter Estimation of an Empirical Manoeuvring Model Using Free-Running Model Tests

Ana Catarina Costa, Haitong Xu, and Carlos Guedes Soares

2021

Cited by: 16; All Open Access, Gold Open Access, Green Open Access

Abs DOI

The work presents the identification and validation of the hydrodynamic coefficients for the surge, sway, and yaw motion. This is performed in two ways: Using simulated data and free-running test data. The identification and validation with the simulation data are carried out using a 25 turning test and a 20-20 zigzag manoeuvring test. For the free-running test data, two zigzag manoeuvres are used: 30-30 zigzag for identification and 20-20 zigzag for validation. A nonlinear manoeuvring model is proposed based on the standard Euler equations, and the hydrodynamic coefficients are computed using empirical equations. To obtain robust results, the truncated singular value decomposition is employed to diminish the multicollinearity and the parameter uncertainties due to noise. The validation is carried out by comparing the result of the measured values with the predictions obtained using the manoeuvring models. Finally, a sensitivity analysis for the simulation data is performed to understand the influence of the parameters in the manoeuvres. © 2021 by the authors.
Optimal parameter estimation of empirical manoeuvring model using free-running ship tests

A.C. Costa, Xu Haitong, and C. Guedes Soares

2021

Cited by: 0; Conference name: 5th International Conference on Maritime Technology and Engineering, MARTECH 2020; Conference date: 16 November 2020 through 19 November 2020; Conference code: 286659

Abs DOI

This work concerns the identification of hydrodynamic coefficients of a specific mathematical manoeuvring model using an optimization method with free-running tests. A nonlinear manoeuvring model is proposed, and the hydrodynamic coefficients are computed using empirical equations. In order to search the optimal values, the least-square method combined with the singular value decomposition was used to optimize the values of the hydrodynamic coefficients, where zig-zag manoeuvre tests were used as training data. The validation is carried by comparing the result of the experiments and the model completed with the coefficients identified by the least square method. © 2021 the Author(s).

2020

Uniformly semiglobally exponential stability of vector field guidance law and autopilot for path-following

Haitong Xu, Thor I. Fossen, and Carlos Guedes Soares

More Information can be found here , 2020

Cited by: 43

Abs DOI HTML PDF Video

A uniform semiglobal exponential stability (USGES) proof for a time-varying vector field guidance law used for path-following control of vehicles is presented. A sliding mode control is introduced for heading autopilot design and Lyapunov methods are used to derive the control law. The equilibrium point of the autopilot error dynamics is proven to be globally exponentially stable (GES). The main result is a time-varying vector field guidance law in cascade with the autopilot. A theorem ensures that the equilibrium point of the cascaded system is uniformly semiglobally exponentially stable. Both straight-line and curved-path path following scenarios are considered in the presence of ocean currents. Simulation studies are carried out to verify the theoretical results. The time-varying guidance laws can also be applied to vehicles in general such as aircraft, underwater vehicles, drones and autonomous vehicles. © 2019 European Control Association
Manoeuvring test for a self-running ship model in various water depth conditions

M.A. Hinostroza, Xu Haitong, and C. Guedes Soares

2020

Cited by: 6; Conference name: 18th International Congress of the International Maritime Association of the Mediterranean, IMAM 2019; Conference date: 9 September 2019 through 11 September 2019; Conference code: 236189

Abs

This paper presents results of manoeuvring tests for a self-running ship model in deep, intermediate and shallow water conditions. The manoeuvring tests were performed for a 2.5 m length self-running ship model equipped with several motion sensors, actuators and communication system, where all signals are synchronized using a Compact-RIO from National Instruments. The tests were performed following the ITTC recommended guidelines and procedures. A total of 48 runs were performed for two types of manoeuvres, four water depths, two model speeds, and three rudder deflection angles. From these experimental tests the influence of the water depth was investigated, specifically the shallow water effects in ship manoeuvres. © 2020 Taylor & Francis Group, London.
Truncated least square support vector machine for parameter estimation of a nonlinear manoeuvring model based on PMM tests

Haitong Xu, Vahid Hassani, and C. Guedes Soares

2020

Cited by: 41; All Open Access, Green Open Access

Abs DOI

A new version of least square support vector machine (LS-SVM), the truncated LS-SVM, is proposed to estimate the nondimensionalized hydrodynamic coefficients. Truncated LS-SVM is shown to be an efficient and robust method that avoids the costly matrix inversion operation in classical LS-SVM using the singular values decomposition. Meanwhile, the smaller singular values are neglected considering their negligible contribution to the solutions. In order to get a robust parameter estimation, the model simplification of the nonlinear manoeuvring model is carried out using a leave-one-out method, considering the trade-off between the parameter uncertainty and accuracy of the numerical model. The simplified manoeuvring model and the values of nondimensionalized hydrodynamic coefficients are presented. The coefficients are estimated using Planar motion mechanism (PMM) tests, which were carried out in a towing tank. The validation process is carried to validate the generalization performance of the obtained numerical model using the PMM test data. © 2020 Elsevier Ltd
Comparing generic and vectorial nonlinear manoeuvring models and parameter estimation using optimal truncated least square support vector machine

Haitong Xu, Vahid Hassani, and C. Guedes Soares

2020

Cited by: 19; All Open Access, Green Open Access

Abs DOI

An optimal truncated least square support vector machine (LS-SVM) is proposed for the parameter estimation of nonlinear manoeuvring models based on captive manoeuvring tests. Two classical nonlinear manoeuvring models, generic and vectorial models, are briefly introduced, and the prime system of SNAME is chosen as the normalization forms for the hydrodynamic coefficients. The optimal truncated LS-SVM is introduced. It is a robust method for parameter estimation by neglecting the small singular values, which contribute negligibly to the solutions and increase the parameter uncertainty. The parameter with a large uncertainty is sensitive to the noise in the data and have a poor generalization performance. The classical LS-SVM and optimal truncated LS-SVM are used to estimate the parameters, and the effectiveness of optimal truncated LS-SVM is validated. The parameter uncertainty for both nonlinear manoeuvring models is discussed. The generalization performance of the obtained numerical models is further tested against the validation set, which is completely left untouched in the training. The R2 goodness-of-fit criterion is used to demonstrate the accuracy of the obtained models. © 2020 Elsevier Ltd
Experimental investigation of shallow water effect on vessel steering model using system identification method

Haitong Xu, M.A. Hinostroza, Zihao Wang, and 1 more author

2020

Cited by: 41

Abs DOI

The shallow water effect on vessel steering model is investigated using the system identification method. Manoeuvring tests were carried out using a scaled free-running ship model with 4 different water depths and 2 speeds. Optimal Truncated LS-SVM is employed to estimate the parameters and the results are validated by comparing with analytical results of Nomoto model, meanwhile, the results are also compared with the least square method, classical LS-SVM, and nu-SVM. The results show that the truncated LS-SVM improve the accuracy of parameter estimation. Based on the obtained parameters, the shallow water effect on the parameters of vessel steering models was discussed and the results revealed that shallow water damages the manoeuvrability of a ship. © 2020 Elsevier Ltd
Manoeuvring modelling of a containership in shallow water based on optimal truncated nonlinear kernel-based least square support vector machine and quantum-inspired evolutionary algorithm

Haitong Xu and C. Guedes Soares

2020

Cited by: 40

Abs DOI

Nonlinear implicit models are proposed for manoeuvring simulation of a container model in shallow water. A series of Planar Motion Mechanism tests of the DTC ship model carried out in a towing tank with shallow water is used for training the nonlinear implicit manoeuvring model. A novel method, nonlinear kernel-based Least Square Support Vector Machine (LS-SVM), is proposed to approximate the nonlinear manoeuvring model. It is a robust method for regression modelling with a low computational cost by reducing the dimensionality of the kernel matrix. The radial basis function kernel is employed in the SVMs to guarantee the performance of the approximation. The quantum-inspired evolutionary algorithm (QEA) is used to search the optimal value of the predefined parameters of the nonlinear kernel-based LS-SVM. The optimal truncated LS-SVM is used to train the nonlinear regression models for ship manoeuvring, and the generalization performance of the obtained nonlinear manoeuvring models is further tested against the validation set. The R2 goodness-of-fit criterion is used to demonstrate the accuracy of the obtained models. © 2019 Elsevier Ltd
VECTOR FIELD GUIDANCE LAW FOR CURVED PATH FOLLOWING OF AN UNDERACTUATED AUTONOMOUS SHIP MODEL

Haitong Xu and C. Guedes Soares

2020

Cited by: 5; All Open Access, Bronze Open Access

Abs DOI

A vector field guidance law and control system for curved path following of an underactuated surface ship model is presented in this paper. In order to obtain the curved path, continuous derivatives piecewise cubic Hermite interpolation is applied for path generation based on the predefined waypoints. A heading autopilot controller is designed based on 2nd order Nomoto’s model and its stability is guaranteed by the Diagram of Vyshnegradsky method. The parameters of Nomoto model are estimated using least square support vector machine based on the manoeuvring tests. The vector field guidance law is applied for both straight and curved path-following control of an underactuated surface ship model. In order to demonstrate the performance, the classical guidance law based on line-of-sight, is adopted for comparison. The results show that the vector field method is capable to solve the guidance problem of underactuated surface ships. © 2020: The Royal Institution of Naval Architects.
Kernel-based support vector regression for nonparametric modeling of ship maneuvering motion

Zihao Wang, Haitong Xu, Li Xia, and 2 more authors

2020

Cited by: 129

Abs DOI

A nonparametric identification method based on ν(‘nu’)-support vector regression (ν-SVR) is proposed to establish robust models of ship maneuvering motion in an easy-to-operate way. Assisted by the kernel trick, the nonlinear model learns implicitly in high-dimensional feature space without a priori model structure. The ν-SVR controls the sparsity automatically, resulting in high efficiency. To improve the practicality, a parameter tuning scheme combining the hold-out validation and the simulation of dynamic processes is designed to avoid overfitting. Taking the KVLCC2 ship as the study object, the experimental data from the SIMMAN database are used to evaluate the method. The selection and pre-processing of training data are discussed. The identified model shows good generalization performance in the prediction of multiple maneuvers not involved in the training set, verifying the effectiveness of the method. © 2020 Elsevier Ltd

2019

Cooperative operation of autonomous surface vehicles for maintaining formation in complex marine environment

M.A. Hinostroza, Haitong Xu, and C. Guedes Soares

2019

Cited by: 63

Abs DOI

A system for motion-planning, collision avoidance, guidance and control of an autonomous surface vehicles formation, navigating in complex marine environment is presented. The motion-planning unit, which is based in angle-guidance fast-marching square method, is specially developed for operation in dynamic and static environments. The collision avoidance unit is based in fuzzy-logic formulation, the guidance unit uses the vector-field guidance formulation and the control unit is composed by a PID heading controller and a speed controller. The leader-follower’s configuration is used for cooperative operation. A set of numerical simulations are carried out for a team of three autonomous surface vehicles navigating in a complex maritime environment including static and dynamic obstacles and the results show good performance of the system. © 2019 Elsevier Ltd
Real-Time Parameter Estimation of a Nonlinear Vessel Steering Model Using a Support Vector Machine

Haitong Xu, M.A. Hinostroza, Vahid Hassani, and 1 more author

2019

Cited by: 34

Abs DOI

The least-square support vector machine (LS-SVM) is used to estimate the dynamic parameters of a nonlinear marine vessel steering model in real-time. First, maneuvering tests are carried out based on a scaled free-running ship model. The parameters are estimated using standard LS-SVM and compared with the theoretical solutions. Then, an online version, a sequential least-square support vector machine, is derived and used to estimate the parameters of vessel steering in real-time. The results are compared with the values estimated by standard LS-SVM with batched training data. By comparison, a sequential least-square support vector machine can dynamically estimate the parameters successfully, and it can be used for designing a dynamic model-based controller of marine vessels. Copyright © 2019 by ASME.
Time-varying vector field guidance law for path following and obstacle avoidance for underactuated autonomous vehicles

Haitong Xu, M.A. Hinostroza, and C. Guedes Soares

2019

Cited by: 0; Conference name: ASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering, OMAE 2019; Conference date: 9 June 2019 through 14 June 2019; Conference code: 154931

Abs DOI

This paper presents a time-varying vector field guidance law for path-following control of underactuated autonomous vehicles. The proposed guidance law employs a time-varying equation to calculate the desired heading angle. A sliding mode controller is designed to track the desired heading angle, and it is proved to be globally exponentially stable (GES). With this controller, the stability proof for guidance system is presented and the equilibrium point of the guidance system is Uniform Global Asymptotic Stable (UGAS). In order to avoid the obstacle when ship approaching the predefined path, a combined Pathfollowing and repelling field based obstacle avoidance system is proposed in this paper. Simulations are carried out to validate the performance of the combined path-following and collision avoidance system. © 2019 American Society of Mechanical Engineers (ASME). All rights reserved.
Use of AIS data for guidance and control of path-following autonomous vessels

Haitong Xu, Hao Rong, and C. Guedes Soares

2019

Cited by: 64

Abs DOI

This paper carries out research on the prototype of an autonomous vessel that is normally used for passenger transportation. A path generation system is proposed using a dynamic time warping algorithm based on Automatic Identification System history data. In order to ensure strong stability properties, a nonlinear controller with globally exponentially stability is introduced for the heading controller. The least square support vector machine is employed to estimate the parameters of the control model based on full-scale manoeuvring tests. The identified results are validated with analytical values. The kinematics and control object of path-following are presented, and a time-varying vector field guidance law is proposed for the path-following control of autonomous vessels. The guidance and control subsystems are interconnected and form a cascade structure. The stability of the coupled guidance and control system is carried out using the cascaded system theory. The proof ensures that the equilibrium point of the cascaded system is uniformly semiglobally exponentially stable. Path following scenario was considered in the presence of currents based on a nonlinear manoeuvring model. Simulation studies were used to verify the theoretical results. © 2019 Elsevier Ltd
Hydrodynamic coefficient estimation for ship manoeuvring in shallow water using an optimal truncated LS-SVM

Haitong Xu and C. Guedes Soares

2019

Cited by: 68

Abs DOI

An optimal truncated least square support vector machine (LS-SVM) is proposed for the parameter estimation of a nonlinear manoeuvring model in shallow water. A nonlinear manoeuvring model in shallow water is briefly introduced and the hydrodynamic coefficients are normalized. A series of Planar Motion Mechanism tests of the DTC ship model carried out in a towing tank with shallow water are used in the study for the estimation of the parameters of the manoeuvring model. The contribution of this paper is to propose the use of the optimal truncated LS-SVM, which is a robust method for parameter estimation that diminishes the uncertainty successfully and has a low computational cost by reducing the dimensionality of the kernel matrix. The classical least square method is also employed to estimate the parameters, and the results are compared with the optimal truncated LS-SVM. The parameter uncertainty is discussed, and the performance of the obtained nonlinear manoeuvring models is tested against a validation set that was left completely untouched during the training. The R2 goodness-of-fit criterion is used to demonstrate the accuracy of the obtained models. © 2019 Elsevier Ltd
Uncertainty analysis of the hydrodynamic coefficients estimation of a nonlinear manoeuvring model based on planar motion mechanism tests

Haitong Xu, Vahid Hassani, and C. Guedes Soares

2019

Cited by: 60

Abs DOI

Uncertainty analysis of the identified hydrodynamic coefficients of a nonlinear manoeuvring model is presented in this paper. The classical parameter estimation method, Least Square, is briefly introduced, and the uncertainty of the hydrodynamic coefficients due to the noise in the measured data is analysed using singular value decomposition. Then, two methods, truncated singular values decomposition and Tikhonov regularization, are introduced to diminish the uncertainty. A nonlinear manoeuvring mathematical model of a marine surface ship is derived using Lagrange’s method. The dimensionless hydrodynamic coefficients are obtained using the Least Squares method, truncated singular values decomposition and Tikhonov regularization with Planar Motion Mechanism test data. The validation process is carried out to test the performance and accuracy of the resulting nonlinear manoeuvring models. The result shows that identification of the uncertain parameters using the truncated singular values decomposition and Tikhonov regularization resulted in good estimating the parameters and significantly diminish the uncertainty. © 2019 Elsevier Ltd

2018

Estimation of hydrodynamic coefficients of a nonlinear manoeuvring mathematical model with free-running ship model tests

Haitong Xu, M.A. Hinostroza, and C. Guedos Soares

2018

Cited by: 43

Abs DOI

Free-running model tests have been carried out based on a scaled chemical tanker ship model, having a guidance, control and navigation system developed and implemented in LabVIEW. In order to make the modelling more flexible and physically more realistic, a modified version of Ahkowitl model was introduced. During the identification process, the model’s structure is fixed and its parameters have been obtained using system identification. A global optimization algorithm has been used to search the optimum values and minimize the loss functions. In order to reduce the effect of noise in the variables, different loss functions considering the empirical errors and generalization performance have been defined and implemented in the system identification program. The hydrodynamic coefficients have been identified based on the manoeuvring test data of free-running ship model. Validations of the system identification algorithm were also carried out and the comparisons with experiments demonstrated the effectiveness of the proposed system identification method. © 2018: The Royal Institution of Naval Architects
Path-planning and path-following control system for autonomous surface vessel

M.A. Hinostroza, Xu Haitong, and C. Guedes Soares

2018

Cited by: 21; Conference name: 17th International Congress of the International Maritime Association of the Mediterranean, IMAM 2017; Conference date: 9 October 2017 through 11 October 2017; Conference code: 220069

Abs

A path-planning and path-following algorithm for autonomous surface vessels is presented. The path-planning algorithm is based in the angle-guidance fast marching square method and the path-following is based in the line-of-sight tracking algorithm. In order to validate the path-planning algorithm, numerical simulations were carried out to search the optimal path in a static environment of 50 × 20 m2 of area including various obstacles. The path-following algorithm was tested with an autonomous surface vehicle tracking a pre-established trajectory including static obstacles. The autonomous surface vehicle is a self-running scaled ship model of 2.5 m equipped with motions sensors, positioning GPS, propulsion DC motors, wi-fi shore communication. From the experiments and numerical simulation a good agreement was found. © 2018 Taylor & Francis Group, London.
An optimized energy-efficient path following algorithm for underactuated marine surface ship model

Haitong Xu and C. Guedes Soares

2018

Cited by: 15

Abs DOI

An optimized path following guidance law is proposed for path-following of an underactuated surface ship. The main purpose of the proposed guidance law is to make a marine vessel travel with more energy efficiency. A combined feedback and feedforward controller is used for the heading control. The feedforward term is designed based on the well-known Nomoto model, whose parameters are estimated using least-square support vector regression. In order to achieve optimal operation of a marine vessel, a global optimization algorithm is employed to search the regularization factors, which are the trade-off between the total cross-track errors and total control energy. The simulation studies are carried out to demonstrate the performance of the proposed guidance law. The proposed method is an effective and practical guidance law and provide an optimal option for marine navigator. © 2018 The Royal Institution of Naval Architects.
Parameters estimation of nonlinear manoeuvring model for marine surface ship based on PMM tests

Haitong Xu, Vahid Hassani, and Carlos Guedes Soares

2018

Cited by: 14; Conference name: ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering, OMAE 2018; Conference date: 17 June 2018 through 22 June 2018; Conference code: 140007

Abs DOI

A nonlinear manoeuvring mathematical model of marine surface ship model is briefly introduced. In order to obtain the hydrodynamic coefficients, system identification is used to estimate the parameters using Planar Motion Mechanism (PMM) test data. Usually, the obtained parameters using measured data have a large uncertainty due to the illconditioned processes of identification. An optimal Truncated Singular Value Decomposition (TSVD) method is exploited to reduce the uncertainty of the estimated parameters. The optimal number of retaining singular values is calculated by using the Lcurve, which is a log-log plot of the norm of a regularized solution versus the norm of the corresponding residual norm. It is a graphical tool for displaying the trade-off between the estimated parameters norm and the corresponding residual error norm. The validation process is performed by comparison of the prediction values with the experimental data in the time domain. Copyright © 2018 ASME.
Real-time parameter estimation of nonlinear vessel steering model using support vector machine

Haitong Xu, Vahid Hassani, M.A. Hinostroza, and 1 more author

2018

Cited by: 11; Conference name: ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering, OMAE 2018; Conference date: 17 June 2018 through 22 June 2018; Conference code: 140007

Abs DOI

The Least-square support vector machine (LS-SVM) is used to estimate the dynamic parameters of a nonlinear marine vessel steering model in real-time. First, manoeuvring tests are carried out based on a scaled free-running ship model. The parameters are estimated using standard LS-SVM and compared with the theoretical solutions. Then, an online version, a sequential least square support vector machine, is derived and used to estimate the parameters of vessel steering in real-time. The results are compared with the values estimated by standard LS-SVM with batched training data. By comparison, sequential least square support vector machine can dynamically estimate the parameters successfully, and it can be used for designing a dynamic model-based controller of marine vessels. Copyright © 2018 ASME.
Motion planning, guidance and control system for autonomous surface vessel

M.A. Hinostroza, Carlos Guedes Soares, and Haitong Xu

2018

Cited by: 10; Conference name: ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering, OMAE 2018; Conference date: 17 June 2018 through 22 June 2018; Conference code: 140007

Abs DOI

This paper presents a motion planning, guidance and control system for an Autonomous surface vessel in a practical maritime environment. The motion planning algorithm is based in the angle-guidance fast marching square method and the guidance system is based in the line-of-sight trajectory tracking algorithm. To validate the motion planning algorithm, numerical simulations were carried out to compute the optimal path in a static environment including various obstacles. The guidance system was tested with an autonomous surface vehicle tracking a pre-established trajectory including static obstacles. The autonomous surface vehicle is a self-propelled scaled ship model of 2.5 m equipped with sensors and actuators, inertial measurement unit, GNSS positioning system, propulsion DC motors, and wireless communication. From the experiments and numerical simulations, a good agreement was found. Copyright © 2018 ASME.
A hybrid controller design for ship autopilot based on free-running model test

Xu Haitong, M.A. Hinostroza, and C. Guedes Soares

2018

Cited by: 6; Conference name: 17th International Congress of the International Maritime Association of the Mediterranean, IMAM 2017; Conference date: 9 October 2017 through 11 October 2017; Conference code: 220069

Abs

Ship steering control system is of critical important for autonomous surface vessels. In this paper, a nonlinear ship steering control system is designed for an underactuated surface ship based on manoeuvring tests using a free-running model. A nonlinear ship steering model is introduced and the parameters are identified using least square support vector regression. The combined linear and nonlinear feedforward and feedback controller is designed for the heading control. Path following simulations are carried out based on a modified nonlinear Abkowitz model with the presence of the ocean current, and the vector field guidance law is also employed in the simulation program. The analysis shows good path following performance for both linear and nonlinear controller. The combined nonlinear feedforward and feedback controller have a better performance and can improve the stability of the ship steering control. © 2018 Taylor & Francis Group, London.

2017

Analysis of electrical drive speed control limitations of a power take-off system for wave energy converters

José F. Gaspar, Mojtaba Kamarlouei, Ashank Sinha, and 5 more authors

2017

Cited by: 21

Abs DOI

The active control of wave energy converters with oil-hydraulic power take-off systems presents important demands on the electrical drives attached to their pumps, in particular on the required drive accelerations and rotational speeds. This work analyzes these demands on the drives and designs reliable control approaches for such drives by simulating a wave-to-wire model in a hardware in-the-loop simulation test rig. The model is based on a point absorber wave energy converter, being the wave, hydrodynamic and oil-hydraulic part simulated in a computer that sends and receives signals from the real embedded components, such as the drive generator, controller and back-to-back converter. Three different control strategies are developed and tested in this test rig and the results revealed that despite the drive limitations to acceleration levels, well above 1 × 104 rpm/s, these do not significantly affect the power take-off efficiency, because the required acceleration peaks rarely achieve these values. Moreover this drive is much more economical than an oil-hydraulic and equivalent one that is able to operate at those peaks of acceleration. © 2017 Elsevier Ltd

2016

Speed control of oil-hydraulic power take-off system for oscillating body type wave energy converters

José F. Gaspar, Mojtaba Kamarlouei, Ashank Sinha, and 5 more authors

2016

Cited by: 52

Abs DOI

The variable displacement oil-hydraulic pumps for the Power Take-Off (PTO) of wave energy converters must work above 80% of maximum displacement in order to have an overall efficiency of approximately 94.5%. This is achieved by controlling their rotational speed when the oil-hydraulic power fluctuates in time. Three speed control strategies have been presented, the first fixing the maximum possible speed in each sea state, the second by slowly varying the pump speed between speed peak values and average ones, and the third by working with highly variable speed reference values. The worst pump efficiency is achieved with the first strategy while the best one with the third strategy. However, the first has less impact than the third one in the pump lifecycle. On the other hand, the second strategy is used to make a trade-off between pump efficiency and lifecycle. However, this paper presents a fourth speed control strategy, which is a hybrid of the second and third strategies. So, the objectives of this paper were to know if these strategies are implementable in a test rig and also on a new PTO concept and determining what modifications should be introduced in these PTO strategies and hardware. This paper also contributes with the application of new methodologies in this field of research for the modelling of pump efficiency and pressure control, such as Neuro-Fuzzy modelling and Fuzzy Logic control systems. © 2016 Elsevier Ltd.
Experimental and numerical simulations of zig-zag manoeuvres of a self-running ship model

M.A. Hinostroza, Xu Haitong, and C. Guedes Soares

2016

Cited by: 7; Conference name: 17th International Congress of the International Maritime Association of the Mediterranean, IMAM 2017; Conference date: 9 October 2017 through 11 October 2017; Conference code: 220069

Abs

Experimental and numerical simulations of manoeuvres of a self-running ship model are presented. The experimental manoeuvring tests were carried out for a self-running ship model in an outdoor pool, following the ITTC recommended procedures. The self-running ship model is 2.5 m length and it is equipped with motions sensor, positioning GPS, propulsion DC motors, wi-fi shore communication, and anemometer. Numerical simulations of ship manoeuvres were carried out based in a 3DOF nonlinear model the same ship model. The manoeuvres considered were 20º/20º and 10º/10º zigzag. Comparisons between the experimental results and numerical simulations are also presented. © 2018 Taylor & Francis Group, London.
Waypoint-following for a marine surface ship model based on vector field guidance law

Haitong Xu and C. Guedes Soares

2016

Cited by: 22; Conference name: 3rd International Conference on Maritime Technology and Engineering, MARTECH 2016; Conference date: 4 July 2016 through 6 July 2016; Conference code: 175999

Abs DOI

A vector field path following algorithm is developed for a surface ship model. A PID heading autopilot controller is developed based on the 2nd Nomoto’s model and the parameters of the model are identified using the least square support vector machine. The Diagram of Vyshnegradsky is used to derive the parameters of the controller. In order to minimize the cross-track errors and heading errors, a path generation is introduced to generate a smooth curved path based on a piecewise cubic Hermite interpolation. A vector field algorithm is used to guide the autonomous surface vehicles to follow the smooth path. The simulation tests are carried out and the results are compared with the traditional line of sight method. The vector filed guidance law can guide the vehicles to follow the predefined the smoothed path with a small cross track error and heading errors with minimum control efforts. The vector field is a practical and robust method for autonomous surface vehicles guidance. © 2016 Taylor & Francis Group, London.
Vector field path following for surface marine vessel and parameter identification based on LS-SVM

Haitong Xu and C. Guedes Soares

2016

Cited by: 96

Abs DOI

A two-dimensional path following control system for autonomous surface vehicles is presented. The guidance system is obtained through a way-point guidance scheme based on a vector field algorithm. Vector field is a simple and robust method and its stability is proved using Lyapunov stability criteria. The 2-degree of freedom (sway-yaw) linear manoeuvring model is chosen as the control model and the parameters are obtained by using the least-square support vector regression. The sensitivity of the vector field algorithm to its parameters is studied and simulation tests are presented to compare the performance of the tradition line-of-sight scheme and vector field algorithm. The results show that the vector field has a better performance for autonomous surface vehicle’s path following control, is a practical and robust method for accurate path following, and can be extended to higher dimensional control and guidance problems. © 2015 Elsevier Ltd. All rights reserved.

2015

An optimized path following algorithm for a surface ship model

Xu Haitong and C. Guedes Soares

2015

Cited by: 1; All Open Access, Green Open Access

Abs DOI

This paper presents an optimized path following algorithm used for way-points tracking of a surface ship. The Nomoto’s model is used for the autopilot design and the parameters are obtained by using the least-square support vector regression. A PID heading autopilot controller is developed. A practical path following algorithm based on the pure pursuit and line of sight guidance law is introduced considering to minimize the total cross-track errors and total control effort. This algorithm is a combination of the pure pursuit and LOS with different gain. The optimal weighted factor is obtained using the Genetic algorithm. The simulation studies are carried out to demonstrate the performance of the proposed algorithm. The presented approach is an effective and practical guidance law for autonomous surface vehicles. © 2015 Taylor & Francis Group, London.
An optimized path following algorithm for a surface ship model

Xu Haitong and C. Guedes Soares

2015

Cited by: 9; Conference name: 16th International Congress of the International Maritime Association of the Mediterranean, IMAM 2015; Conference date: 21 September 2015 through 24 September 2015; Conference code: 156939; All Open Access, Gold Open Access

Abs DOI

This paper presents an optimized path following algorithm used for way-points tracking of a surface ship. The Nomoto,s model is used for the autopilot design and the parameters are obtained by using the least-square support vector regression. A PID heading autopilot controller is developed. A practical path following algorithm based on the pure pursuit and line of sight guidance law is introduced considering to minimize the total cross-track errors and total control effort. This algorithm is a combination of the pure pursuit and LOS with different gain. The optimal weighted factor is obtained using the Genetic algorithm. The simulation studies are carried out to demonstrate the performance of the proposed algorithm. The presented approach is an effective and practical guidance law for autonomous surface vehicles. © 2015 Taylor and Francis Group.

2014

An experimental research on nonlinear roll hydrodynamic characteristics of a composite trimaran using ε-SVR

Haitong Xu, Songlin Yang, Qingwei Ma, and 3 more authors

2014

Cited by: 0

Abs

The rolling motion behaviour of a composite trimaran was studied in the Jiangsu University of Science and Technology Ship hydrodynamic Centre. Series of the free roll decay tests were carried out in the seakeeping tank. The mathematical model of rolling motion mode is established considering both linear and nonlinear ship motion. The overall seakeeping behaviour of the vessel is discussed and particular attention is paid to the roll motion. The results of time-domain nonlinear hydrodynamic identification using ε-Support Vector Regression are validated against the model tests. The error of ε-Support Vector Regression is discussed and the relative error is less than 3%. The results suggest that the ε-Support Vector Regression is a reliable method for identification of the roll motion owning to its inherent benefits. Parametric roll is discussed and test results are presented. The nonlinear effect on the roll motions of the draft, spacing and attitude of side hulls is evaluated. The paper ends with a discussion on configurations of side hull for composite trimaran vessels. This paper can provide technical support in the optimization design of composite trimaran and the research of composite multi-hull ship.

2013

System identification of unmanned planning boat rolling motion mode

Wanglin Yang, Haitong Xu, Songlin Yang, and 1 more author

2013

Cited by: 0; Conference name: 2013 4th International Conference on Computing, Control and Industrial Engineering, CCIE 2013; Conference date: 27 October 2013 through 28 October 2013; Conference code: 100705

Abs DOI

In this paper, the author took an unmanned planning boat as the object of study and carried out a series of rolling decay ship model test by changing the draft. The author established nine kinds of mathematical model of rolling decay motion model system identification by using different damping and righting moment and established the optimization calculation of the objective function based on the principle of system identification. Then the author adapted the genetic algorithm of system identification program which is based on the Visual Basic 6.0 and got 15 kinds of identification programs. By doing research on the first three cycles of the series of rolling angular velocity curve and identifying respectively the resulting 15 kinds of identification programs, the author confirmed the feasibility of the adapted program. Comparing different drafts and the initial roll angle identification results, the author found a reasonable hydrostatic roll motion equation of the unmanned planning boat in the case of different drafts and the initial roll angle, and made a preliminary analysis. © (2013) Trans Tech Publications, Switzerland.
Research on the rolling motion mode of composite trimaran

Haitong Xu, Songlin Yang, Yiyan Wen, and 2 more authors

2013

Cited by: 0; Conference name: 23rd International Offshore and Polar Engineering Conference, ISOPE 2013; Conference date: 30 June 2013 through 5 July 2013; Conference code: 98971

Abs

This paper investigate the swaying motion performance, which was affected by the posture and the position of small side hull by using the model test. The series of free rolling decay test was carried out by changing the draft, the transverse distance of side hull and the inclination angle of side hulls. Considering of the special structure of composite trimaran and the complex flow field around the trimaran in the process of rolling, the author established the mathematical model of rolling motion. By identifying the composite trimaran rolling motion mode ,we got the curve of hydrodynamic coefficients by a reliable and efficient system identification software. The author analyzed the phenomenon of roll amplitudes mutation and got some conclusions. In this paper, a research method of composite trimaran rolling motion is obtained, which can provide technical support in composite trimaran optimization design and research of composite multi-hull ship. Copyright © 2013 by the International Society of Offshore and Polar Engineers (ISOPE).
Preliminary study on maneuvering motion pattern of unmanned composite trimaran ship model

Jian Cui, Songlin Yang, and Haitong Xu

2013

Cited by: 1; Conference name: 2nd International Conference on Civil Engineering and Transportation, ICCET 2012; Conference date: 27 October 2012 through 28 October 2012; Conference code: 95112

Abs DOI

The composite trimaran is characterized by adding the hydrofoils with different aspect ration in the main hull and sides of the conventional trimaran hull. Regarding the programmable automatic controller as the core, the paper designed the unmanned intelligent control system of the composite trimaran ship model, used VB.NET language to design the maneuverability simulation platform on MMG. And designed six rudder blades with different aspect ratio, and carried out a series of manipulation turning tests of the ship model under different speed and rudder angle. Through comparing with experimental data and the simulation results, it has verified the reliability of the simulation platform. Then with the system identification methods, the paper has discussed the aspect ratio of the rudder which has influence on the manipulation rotary motion of the composite trimaran ship model, and the manipulation rotary performance of the composite trimaran ship model in different speed and rudder angle. © (2013) Trans Tech Publications, Switzerland.