Pub Date : 2026-02-03DOI: 10.1016/j.oceaneng.2026.124451
Xi Zhang , Jianbo Wu , Liang Cheng , Qing Wang , Yinglin Ke
Path planning is crucial for autonomous underwater vehicles (AUVs), ensuring their safety and demonstrating their intelligence. However, the underwater environment is unstructured, with unknown static and dynamic obstacles. Moreover, the kinematic constraints of the AUV's movement add to the complexity of planning. To address these challenges, this paper proposes a hybrid approach that combines crested porcupine optimization (CPO) with an improved dynamic window approach (DWA), called DFDWA. First, CPO is used for global path planning to find an optimal solution. Second, to better avoid suddenly appearing dynamic obstacles, we enhance the traditional DWA in four ways: extending it to three dimensions to better model the AUV's motion; incorporating a three-dimensional distance field to improve dynamic obstacle avoidance; calculating the Distance at Closest Point of Approach (DCPA) for collision risk assessment; and using fuzzy logic to adaptively tune DWA parameters. Finally, simulation results demonstrate that the proposed algorithm effectively avoids both static and dynamic obstacles, reduces detours while maintaining safety, thereby making a valuable contribution to future AUV path planning.
{"title":"AUV path planning based on crested porcupine optimizer and improved fuzzy DWA with collision risk assessment","authors":"Xi Zhang , Jianbo Wu , Liang Cheng , Qing Wang , Yinglin Ke","doi":"10.1016/j.oceaneng.2026.124451","DOIUrl":"10.1016/j.oceaneng.2026.124451","url":null,"abstract":"<div><div>Path planning is crucial for autonomous underwater vehicles (AUVs), ensuring their safety and demonstrating their intelligence. However, the underwater environment is unstructured, with unknown static and dynamic obstacles. Moreover, the kinematic constraints of the AUV's movement add to the complexity of planning. To address these challenges, this paper proposes a hybrid approach that combines crested porcupine optimization (CPO) with an improved dynamic window approach (DWA), called DFDWA. First, CPO is used for global path planning to find an optimal solution. Second, to better avoid suddenly appearing dynamic obstacles, we enhance the traditional DWA in four ways: extending it to three dimensions to better model the AUV's motion; incorporating a three-dimensional distance field to improve dynamic obstacle avoidance; calculating the Distance at Closest Point of Approach (DCPA) for collision risk assessment; and using fuzzy logic to adaptively tune DWA parameters. Finally, simulation results demonstrate that the proposed algorithm effectively avoids both static and dynamic obstacles, reduces detours while maintaining safety, thereby making a valuable contribution to future AUV path planning.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"351 ","pages":"Article 124451"},"PeriodicalIF":5.5,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146170600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-03DOI: 10.1016/j.oceaneng.2026.124460
Yujia Liu , Luchun Yang , Maokun Ye , Decheng Wan , Moustafa Abdel-Maksoud
The Moving Particle Semi-implicit (MPS) method is a widely used Lagrangian Particle method for simulating free-surface flows. In conventional MPS simulations, the solution of the pressure Poisson equation (PPE) in the pressure-projection step typically constitutes a major portion of the overall computational cost, particularly for large-scale particle systems. To address this issue, we propose a data-driven hybrid approach that integrates the MPS method with the Graph Attention Network (GAT), denoted as MPS-GAT. In this approach, GAT serves as a surrogate model to replace the traditional PPE solver for pressure estimation in MPS. The effectiveness of the proposed method is evaluated using a benchmark case of tank sloshing. The accuracy is verified by comparing the pressure predictions from MPS-GAT with numerical results obtained from solving the PPE. Spatial errors are quantified by differences in mesh-interpolated mean fields between MPS-GAT and traditional MPS method, and temporal errors by the discrepancy in the mean particle velocity and pressure over time. To evaluate generalization, the model is tested on sloshing scenarios with filling ratios, excitation frequencies, and amplitudes not included in the training data. Remarkably, the model exhibited exceptional generalization performance under internal-obstacle configurations despite their complete absence from the training distribution. Furthermore, the proposed hybrid method significantly improves computational efficiency. In our tests with particle counts from 1000 to 130000, MPS-GAT reduces the pressure estimation time by more than 30 times compared with the traditional MPS method when the particle number exceeds 120000. The speedup ratio increases further with larger particle counts, demonstrating clear advantages for large scale free surface flow simulations.
{"title":"Accelerating the solution of Poisson equation in MPS method for tank sloshing using graph attention network","authors":"Yujia Liu , Luchun Yang , Maokun Ye , Decheng Wan , Moustafa Abdel-Maksoud","doi":"10.1016/j.oceaneng.2026.124460","DOIUrl":"10.1016/j.oceaneng.2026.124460","url":null,"abstract":"<div><div>The Moving Particle Semi-implicit (MPS) method is a widely used Lagrangian Particle method for simulating free-surface flows. In conventional MPS simulations, the solution of the pressure Poisson equation (PPE) in the pressure-projection step typically constitutes a major portion of the overall computational cost, particularly for large-scale particle systems. To address this issue, we propose a data-driven hybrid approach that integrates the MPS method with the Graph Attention Network (GAT), denoted as MPS-GAT. In this approach, GAT serves as a surrogate model to replace the traditional PPE solver for pressure estimation in MPS. The effectiveness of the proposed method is evaluated using a benchmark case of tank sloshing. The accuracy is verified by comparing the pressure predictions from MPS-GAT with numerical results obtained from solving the PPE. Spatial errors are quantified by differences in mesh-interpolated mean fields between MPS-GAT and traditional MPS method, and temporal errors by the discrepancy in the mean particle velocity and pressure over time. To evaluate generalization, the model is tested on sloshing scenarios with filling ratios, excitation frequencies, and amplitudes not included in the training data. Remarkably, the model exhibited exceptional generalization performance under internal-obstacle configurations despite their complete absence from the training distribution. Furthermore, the proposed hybrid method significantly improves computational efficiency. In our tests with particle counts from 1000 to 130000, MPS-GAT reduces the pressure estimation time by more than 30 times compared with the traditional MPS method when the particle number exceeds 120000. The speedup ratio increases further with larger particle counts, demonstrating clear advantages for large scale free surface flow simulations.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"351 ","pages":"Article 124460"},"PeriodicalIF":5.5,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146170595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-03DOI: 10.1016/j.oceaneng.2026.124347
Aksel Trentemøller Frafjord , Erlend M. Coates , Peihua Han , Tongtong Wang , Italo Aldo Campodonico Avendano , Øivind Kåre Kjerstad
Unlike conventional non-linear state observers that rely solely on physics-based models, this study proposes a hybrid state observer that combines a physics-based control model with a data-driven correction model to improve state estimation for maritime surface vessels. Five deep neural network architectures, trained on synthetic data akin to what can be obtained during sea trials, serve as correction models within the hybrid design. These architectures are evaluated through simulation scenarios featuring variable ocean currents and wind. The results show that the hybrid observer using a fully connected neural network with three layers of 64 neurons reduces estimation error by 30% compared to a fixed-gain non-linear observer based solely on a physics-based model. This improvement highlights the potential of hybrid observers to enhance state estimation accuracy, which is essential for the overall control system performance.
{"title":"A hybrid non-linear observer for maritime surface vessel state estimation using physics-based and data-driven modelling","authors":"Aksel Trentemøller Frafjord , Erlend M. Coates , Peihua Han , Tongtong Wang , Italo Aldo Campodonico Avendano , Øivind Kåre Kjerstad","doi":"10.1016/j.oceaneng.2026.124347","DOIUrl":"10.1016/j.oceaneng.2026.124347","url":null,"abstract":"<div><div>Unlike conventional non-linear state observers that rely solely on physics-based models, this study proposes a hybrid state observer that combines a physics-based control model with a data-driven correction model to improve state estimation for maritime surface vessels. Five deep neural network architectures, trained on synthetic data akin to what can be obtained during sea trials, serve as correction models within the hybrid design. These architectures are evaluated through simulation scenarios featuring variable ocean currents and wind. The results show that the hybrid observer using a fully connected neural network with three layers of 64 neurons reduces estimation error by 30% compared to a fixed-gain non-linear observer based solely on a physics-based model. This improvement highlights the potential of hybrid observers to enhance state estimation accuracy, which is essential for the overall control system performance.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"351 ","pages":"Article 124347"},"PeriodicalIF":5.5,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146170618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-03DOI: 10.1016/j.oceaneng.2026.124449
Jie Wang , Yuan Sun , Sheng Xu , Shuai Li
Cavitation erosion of marine protective coatings poses a significant challenge to the durability of marine structures. This study systematically investigates the failure mechanisms of ship hull antifouling coatings under ultrasonic cavitation through integrated experimental analysis. The dynamics of cavitation bubbles in both free-field and near-wall environments are characterized across varying ultrasonic power levels. Key bubble-wall interaction mechanisms are identified, particularly the formation of wall-attached bubble clusters that impose intense cyclic loading on material surfaces, inducing fatigue damage. Erosion patterns on aluminum sheets substrates and coated steel sheets reveal that the spatial distribution and population of these pulsating wall-attached bubble clusters directly govern the morphology and severity of cavitation damage. For antifouling coatings, erosion initiates as localized pitting and plastic deformation under repeated bubble impacts. With increasing loading cycles, micro-damages coalesce, leading to stress concentration and eventual coating spallation. Parametric studies on stand-off distance and acoustic power uncover a critical stand-off distance ( mm) and a non-monotonic relationship between ultrasonic power and coating damage. At high power levels (Wa ≥ 384 W), the probe-tip-attached cavitation cloud expands significantly, acting as an acoustic shield and suppressing the number of cavitation bubbles near and attached to the wall. The most severe erosion occurs at an intermediate power level ( W). At this power, an optimal synergy between acoustic driving and bubble-wall coupling maximizes cavitation-induced cyclic loading on the coating surface, resulting in significantly intensified damage.
{"title":"Ultrasonic cavitation erosion of marine protective coatings: From bubbles behavior to coating damage","authors":"Jie Wang , Yuan Sun , Sheng Xu , Shuai Li","doi":"10.1016/j.oceaneng.2026.124449","DOIUrl":"10.1016/j.oceaneng.2026.124449","url":null,"abstract":"<div><div>Cavitation erosion of marine protective coatings poses a significant challenge to the durability of marine structures. This study systematically investigates the failure mechanisms of ship hull antifouling coatings under ultrasonic cavitation through integrated experimental analysis. The dynamics of cavitation bubbles in both free-field and near-wall environments are characterized across varying ultrasonic power levels. Key bubble-wall interaction mechanisms are identified, particularly the formation of wall-attached bubble clusters that impose intense cyclic loading on material surfaces, inducing fatigue damage. Erosion patterns on aluminum sheets substrates and coated steel sheets reveal that the spatial distribution and population of these pulsating wall-attached bubble clusters directly govern the morphology and severity of cavitation damage. For antifouling coatings, erosion initiates as localized pitting and plastic deformation under repeated bubble impacts. With increasing loading cycles, micro-damages coalesce, leading to stress concentration and eventual coating spallation. Parametric studies on stand-off distance and acoustic power uncover a critical stand-off distance (<span><math><mrow><msub><mi>d</mi><mrow><mi>c</mi></mrow></msub><mo>=</mo><mn>2.8</mn></mrow></math></span> mm) and a non-monotonic relationship between ultrasonic power and coating damage. At high power levels (<em>W</em><sub>a</sub> ≥ 384 W), the probe-tip-attached cavitation cloud expands significantly, acting as an acoustic shield and suppressing the number of cavitation bubbles near and attached to the wall. The most severe erosion occurs at an intermediate power level (<span><math><mrow><msub><mi>W</mi><mrow><mi>a</mi></mrow></msub><mo>=</mo><mn>384</mn></mrow></math></span> W). At this power, an optimal synergy between acoustic driving and bubble-wall coupling maximizes cavitation-induced cyclic loading on the coating surface, resulting in significantly intensified damage.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"351 ","pages":"Article 124449"},"PeriodicalIF":5.5,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146170598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-03DOI: 10.1016/j.oceaneng.2026.124522
Haoxun Yuan , Yingchun Xie , Guijie Liu , Di-Lin Chen , Jinchi Zhu , Jie Liu , Songping Meng
As a key equipment for marine scientific research, underwater vehicles rely on near-field detection as a main function for localization and cooperative swarm operations. However, conventional acoustic and optical methods are facing challenges due to the increasing diversity of missions and complexity of environments. In this study, we integrate the artificial lateral line system, the Cramer–Rao Lower Bound (CRLB) theory, and the Multi-Island Genetic Algorithm (MIGA) to quantitatively evaluate the near-field localization performance of sensor arrays and optimize their configuration parameters. Orthogonal test results indicate a significant positive correlation between array parameters and localization performance. In particular, the body array parameters determine the amount of information contained in the observational data, emerging as the most influential factor affecting localization accuracy. Optimization results further reveal that appropriately increasing the interval between body sensors can effectively compensate for the loss of pressure field sampling density caused by a reduction in the number of body sensors. Monte Carlo simulations validate the accuracy of the theoretical analysis and highlight differences in computational efficiency among the algorithms employed. The proposed quantitative evaluation and optimization framework for array localization performance offers unique insights into the design of artificial lateral line systems for miniaturized underwater vehicles.
{"title":"Performance evaluation of near-field localization for artificial lateral line based on theoretical analysis and orthogonal test","authors":"Haoxun Yuan , Yingchun Xie , Guijie Liu , Di-Lin Chen , Jinchi Zhu , Jie Liu , Songping Meng","doi":"10.1016/j.oceaneng.2026.124522","DOIUrl":"10.1016/j.oceaneng.2026.124522","url":null,"abstract":"<div><div>As a key equipment for marine scientific research, underwater vehicles rely on near-field detection as a main function for localization and cooperative swarm operations. However, conventional acoustic and optical methods are facing challenges due to the increasing diversity of missions and complexity of environments. In this study, we integrate the artificial lateral line system, the Cramer–Rao Lower Bound (CRLB) theory, and the Multi-Island Genetic Algorithm (MIGA) to quantitatively evaluate the near-field localization performance of sensor arrays and optimize their configuration parameters. Orthogonal test results indicate a significant positive correlation between array parameters and localization performance. In particular, the body array parameters determine the amount of information contained in the observational data, emerging as the most influential factor affecting localization accuracy. Optimization results further reveal that appropriately increasing the interval between body sensors can effectively compensate for the loss of pressure field sampling density caused by a reduction in the number of body sensors. Monte Carlo simulations validate the accuracy of the theoretical analysis and highlight differences in computational efficiency among the algorithms employed. The proposed quantitative evaluation and optimization framework for array localization performance offers unique insights into the design of artificial lateral line systems for miniaturized underwater vehicles.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"351 ","pages":"Article 124522"},"PeriodicalIF":5.5,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146170599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-03DOI: 10.1016/j.oceaneng.2026.124488
Jian Zou, Bangwei Liu, Yihang Shan, Ruixiang Liu, Hui Li
This paper investigates the water entry of elastic wedges with curved boundaries using a fully nonlinear boundary element method (BEM). The numerical model introduces an auxiliary function method to simultaneously solve the motion, deformation, and hydrodynamic pressure during the water entry process. Flow separation is also considered in the simulation to extend the effective simulation duration. The validity of the present numerical model is verified through comparisons with published results on the water entry of a straight-wall elastic wedge and a cylindrical shell. In the study of curved wedges, the convex wedge generates a large transient slamming load in the early stage of water entry, leading to significant elastic vibrations of the boundary. In contrast, the concave wedge has high slamming pressure when the jet root reaches the upper edge of the boundary. Subsequent flow separation causes a rapid decrease in slamming pressure and excites elastic vibrations of the boundary. Compared with the straight-wall boundary, the peak stress responses on both convex and concave boundaries are significantly reduced by more than 50 %, although they experience larger slamming loads.
{"title":"Study on water entry of curved elastic wedge using fully nonlinear boundary element method","authors":"Jian Zou, Bangwei Liu, Yihang Shan, Ruixiang Liu, Hui Li","doi":"10.1016/j.oceaneng.2026.124488","DOIUrl":"10.1016/j.oceaneng.2026.124488","url":null,"abstract":"<div><div>This paper investigates the water entry of elastic wedges with curved boundaries using a fully nonlinear boundary element method (BEM). The numerical model introduces an auxiliary function method to simultaneously solve the motion, deformation, and hydrodynamic pressure during the water entry process. Flow separation is also considered in the simulation to extend the effective simulation duration. The validity of the present numerical model is verified through comparisons with published results on the water entry of a straight-wall elastic wedge and a cylindrical shell. In the study of curved wedges, the convex wedge generates a large transient slamming load in the early stage of water entry, leading to significant elastic vibrations of the boundary. In contrast, the concave wedge has high slamming pressure when the jet root reaches the upper edge of the boundary. Subsequent flow separation causes a rapid decrease in slamming pressure and excites elastic vibrations of the boundary. Compared with the straight-wall boundary, the peak stress responses on both convex and concave boundaries are significantly reduced by more than 50 %, although they experience larger slamming loads.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"351 ","pages":"Article 124488"},"PeriodicalIF":5.5,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146170678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-03DOI: 10.1016/j.oceaneng.2026.124275
Jiayuan Zhuang , Qingxiang Hai , Chuan Ma , Xinyu Li , Jun Yang , Jiandong Wang , Cong Huang , Lei Zhang
Planing boats are characterized by excellent rapidity. To improve their seakeeping performance, an axe-bow design was employed. In this study, based on the parent boat, a parametric modeling approach was utilized to complete the bow design of the axe-bow planing boat. Subsequently, model tests were conducted to compare the hydrodynamic performances of the axe-bow planing boat and the parent boat in calm water and regular waves. The test equipment consists of a seaworthiness instrument system and a data acquisition system, which are used to measure values such as trim angle, heave, and vertical acceleration, as well as to monitor the fluid around the boat. The test results show that, under calm water conditions, the trim of the axe-bow planing boat is significantly reduced compared to the parent boat. In terms of resistance, the two boats perform similarly, but the peak of the resistance of the axe-bow planing boat is delayed to a higher speed. Under wave conditions, the advantages of the axe-bow planing boat are more obvious: as the wavelength increases, its heave and trim performance is better than the parent boat. Additionally, to further explore the seakeeping performance advantages of axe-bow planing boat in calm water and regular waves, tests under different locations of the center of gravity were carried out, and the results were compared and analyzed. The key takeaway from this study is that an modified axe-bow with appropriate LCG improves seakeeping by reducing dynamic trim, harmonic motions, and added resistance, without sacrificing low-to-medium-speed resistance.
{"title":"A study on the seakeeping performance of the axe-bow planing boat by model experiments","authors":"Jiayuan Zhuang , Qingxiang Hai , Chuan Ma , Xinyu Li , Jun Yang , Jiandong Wang , Cong Huang , Lei Zhang","doi":"10.1016/j.oceaneng.2026.124275","DOIUrl":"10.1016/j.oceaneng.2026.124275","url":null,"abstract":"<div><div>Planing boats are characterized by excellent rapidity. To improve their seakeeping performance, an axe-bow design was employed. In this study, based on the parent boat, a parametric modeling approach was utilized to complete the bow design of the axe-bow planing boat. Subsequently, model tests were conducted to compare the hydrodynamic performances of the axe-bow planing boat and the parent boat in calm water and regular waves. The test equipment consists of a seaworthiness instrument system and a data acquisition system, which are used to measure values such as trim angle, heave, and vertical acceleration, as well as to monitor the fluid around the boat. The test results show that, under calm water conditions, the trim of the axe-bow planing boat is significantly reduced compared to the parent boat. In terms of resistance, the two boats perform similarly, but the peak of the resistance of the axe-bow planing boat is delayed to a higher speed. Under wave conditions, the advantages of the axe-bow planing boat are more obvious: as the wavelength increases, its heave and trim performance is better than the parent boat. Additionally, to further explore the seakeeping performance advantages of axe-bow planing boat in calm water and regular waves, tests under different locations of the center of gravity were carried out, and the results were compared and analyzed. The key takeaway from this study is that an modified axe-bow with appropriate <em>L</em><sub>CG</sub> improves seakeeping by reducing dynamic trim, harmonic motions, and added resistance, without sacrificing low-to-medium-speed resistance.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"351 ","pages":"Article 124275"},"PeriodicalIF":5.5,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146170680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-02DOI: 10.1016/j.oceaneng.2026.124453
Chen Xu, Jianye Gong, Qikun Shen
This paper investigates the predetermined performance adaptive fault-tolerant control problem for unmanned surface vessel system in the presence of unknown power distortion under complex ocean environments. First, the state signal distortion caused by the measurement drifts is considered in the unmanned surface vessel, and the transformed position error dynamics are introduced based on the error reconstruction technique to address the difficulties of control design due to the unmeasurable state information. Furthermore, an adaptive compensation signal is developed to estimate the uncertain oceanic disturbances in real time, and coupled with an auxiliary dynamic system to mitigate the effects of saturation constraints. By designing a predetermined performance function, the position errors under the proposed scheme can quickly enter into a tunable interval within a time set in advance. The theoretical analysis shows that all signals in the closed-loop system are uniformly ultimately bounded. Finally, the validity of the developed control scheme is verified by simulation of three programmable unmanned surface vessels.
{"title":"Error reconstruction based predetermined performance fault-tolerant control for USV system against unknown power distortion and multiple input constraints","authors":"Chen Xu, Jianye Gong, Qikun Shen","doi":"10.1016/j.oceaneng.2026.124453","DOIUrl":"10.1016/j.oceaneng.2026.124453","url":null,"abstract":"<div><div>This paper investigates the predetermined performance adaptive fault-tolerant control problem for unmanned surface vessel system in the presence of unknown power distortion under complex ocean environments. First, the state signal distortion caused by the measurement drifts is considered in the unmanned surface vessel, and the transformed position error dynamics are introduced based on the error reconstruction technique to address the difficulties of control design due to the unmeasurable state information. Furthermore, an adaptive compensation signal is developed to estimate the uncertain oceanic disturbances in real time, and coupled with an auxiliary dynamic system to mitigate the effects of saturation constraints. By designing a predetermined performance function, the position errors under the proposed scheme can quickly enter into a tunable interval within a time set in advance. The theoretical analysis shows that all signals in the closed-loop system are uniformly ultimately bounded. Finally, the validity of the developed control scheme is verified by simulation of three programmable unmanned surface vessels.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"351 ","pages":"Article 124453"},"PeriodicalIF":5.5,"publicationDate":"2026-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146170735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-02DOI: 10.1016/j.oceaneng.2026.124446
Shangming Wang, Minh Jimmy Le, Guang Yin, Muk Chen Ong
This study proposes a calculation framework of the form factor (1+k) for predicting the total resistance of trimarans and examines its variation with forward speed and outrigger layout. A total of 30 scenarios are analyzed, comprising six outrigger layouts and five forward speeds. Computational Fluid Dynamics (CFD) simulations using OpenFOAM are employed to obtain the total resistance across these configurations. The numerical results are validated against experimental data, demonstrating the accuracy and efficiency of the CFD approach. Additionally, potential flow theory is applied to determine the wave-making resistance, enabling the derivation of the form factor for each scenario. The study systematically analyzes how the form factor varies with trimaran forward speed and outrigger layout. The results reveal distinct trends in the total resistance of trimarans concerning longitudinal distance (), transverse distance (), and forward speed. Furthermore, a neural network is developed to predict the form factor, enabling an efficient estimation of total resistance across various outrigger layouts and forward speeds. The neural network is trained through two strategies using a dataset derived from the numerical simulations. The validation results show that the trained neural network using both strategies can accurately predict the trimaran total resistance, achieving an average error below 5 % and a maximum error not exceeding 10 %.
{"title":"A prediction methodology of trimaran form factor (1+k) based on neural network","authors":"Shangming Wang, Minh Jimmy Le, Guang Yin, Muk Chen Ong","doi":"10.1016/j.oceaneng.2026.124446","DOIUrl":"10.1016/j.oceaneng.2026.124446","url":null,"abstract":"<div><div>This study proposes a calculation framework of the form factor (1+k) for predicting the total resistance of trimarans and examines its variation with forward speed and outrigger layout. A total of 30 scenarios are analyzed, comprising six outrigger layouts and five forward speeds. Computational Fluid Dynamics (CFD) simulations using OpenFOAM are employed to obtain the total resistance across these configurations. The numerical results are validated against experimental data, demonstrating the accuracy and efficiency of the CFD approach. Additionally, potential flow theory is applied to determine the wave-making resistance, enabling the derivation of the form factor for each scenario. The study systematically analyzes how the form factor varies with trimaran forward speed and outrigger layout. The results reveal distinct trends in the total resistance of trimarans concerning longitudinal distance (<span><math><mrow><mi>a</mi></mrow></math></span>), transverse distance (<span><math><mrow><mi>p</mi></mrow></math></span>), and forward speed. Furthermore, a neural network is developed to predict the form factor, enabling an efficient estimation of total resistance across various outrigger layouts and forward speeds. The neural network is trained through two strategies using a dataset derived from the numerical simulations. The validation results show that the trained neural network using both strategies can accurately predict the trimaran total resistance, achieving an average error below 5 % and a maximum error not exceeding 10 %.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"351 ","pages":"Article 124446"},"PeriodicalIF":5.5,"publicationDate":"2026-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146170671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-02DOI: 10.1016/j.oceaneng.2026.124435
Kang Wang , Feng-Ping Yuan , Qiang Li , Yu-Hang Wang , Yu-Xiao Luo , Jie Yu , Cheng-Yang Du
To accurately determine the stress concentration factors (SCFs) in concrete-filled steel tubular (CFST) KK-joints with internal ring stiffeners under in-plane and out-of-plane bending moment, 208 finite element (FE) analyses were conducted to investigate the influence of key geometric parameters (β, γ, τ, θ) on the SCFs distribution along the weld toe. The analysis demonstrated that the concrete infill and ring stiffeners result in a complex SCFs distribution pattern, where the fluctuation trend, peak values, and their locations were jointly influenced by both load direction and geometric parameters. Based on the parametric findings, a set of parametric equations were proposed to predict the SCFs distribution curves on both the chord and brace sides. The accuracy and reliability of these equations were further confirmed through verification against the UK department of energy assessment criteria and additional FE models, demonstrating their excellent potential for engineering application.
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