Pub Date : 2025-02-01DOI: 10.1016/j.oceaneng.2024.120002
Sen Han , Lingxiao Yan , Jiahao Sun , Shifeng Ding , Fang Li , Feng Diao , Li Zhou
Automatic berthing is considered one of the most challenging problems for underactuated unmanned surface vehicles (USVs) due to the influence factors such as rudder effect, environmental disturbances, and control uncertainties. This paper focuses on trajectory planning and tracking to address this problem. The hybrid approach initially employs a reverse search strategy to plan the global berthing trajectory, with the terminal part of this trajectory subsequently being reconstructed and optimized by taking into account environmental loads and USV dynamic model. A nonlinear MPC controller is designed for real-time tracking of the berthing trajectory. The rudder effect constraints related to USV speed is supplemented to the dynamic model to alleviate the problem of poor maneuverability at low speed. The whole trajectory planning and tracking scheme of automatic berthing is simulated at Dalian Port considering environmental loads and uncertainties in control. The results show that the scheme has quite fast solving speed of trajectory planning and robust control of trajectory tracking.
{"title":"Hybrid trajectory planning and tracking for automatic berthing: A grid-search and optimal control integration approach","authors":"Sen Han , Lingxiao Yan , Jiahao Sun , Shifeng Ding , Fang Li , Feng Diao , Li Zhou","doi":"10.1016/j.oceaneng.2024.120002","DOIUrl":"10.1016/j.oceaneng.2024.120002","url":null,"abstract":"<div><div>Automatic berthing is considered one of the most challenging problems for underactuated unmanned surface vehicles (USVs) due to the influence factors such as rudder effect, environmental disturbances, and control uncertainties. This paper focuses on trajectory planning and tracking to address this problem. The hybrid approach initially employs a reverse search strategy to plan the global berthing trajectory, with the terminal part of this trajectory subsequently being reconstructed and optimized by taking into account environmental loads and USV dynamic model. A nonlinear MPC controller is designed for real-time tracking of the berthing trajectory. The rudder effect constraints related to USV speed is supplemented to the dynamic model to alleviate the problem of poor maneuverability at low speed. The whole trajectory planning and tracking scheme of automatic berthing is simulated at Dalian Port considering environmental loads and uncertainties in control. The results show that the scheme has quite fast solving speed of trajectory planning and robust control of trajectory tracking.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"317 ","pages":"Article 120002"},"PeriodicalIF":4.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143094787","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 : 2025-02-01DOI: 10.1016/j.oceaneng.2024.120022
Wei Tao , Jinwei Sun , Shuqing Wang , Shixuan Liu , Linqiang Zhang , Yunming Han
The coupled dynamic analysis of moored floating structures has often been conducted in the time domain by iteratively solving the Cummins equation, treating the mooring effects as an additional nonlinear load. However, the time domain (TD) method requires performing a convolution integral at each time step, which is costly in computational time. This paper innovatively develops an efficient hybrid Laplace-time domain method (HLTD) on implementing the coupled dynamic analysis of moored floating structures. The proposed method divides the external load into a number of segments and models the mooring system by the catenary theory. Under each segment, while the iterative operations used in the TD method is borrowed to handle the coupled behavior, the HLTD method computes the motions of the floating structure under each iteration by the pole-residue operations in the Laplace domain (LD). As the complicated convolutional integral computation required in the TD method is replaced by simple algebraic pole-residue calculations in the complex plane, the HLTD method is more efficient. Additionally, the HLTD method derives analytical response solutions for the moored floating system. Its efficiency and accuracy are demonstrated by comparing with the TD method through a moored float-over barge to irregular waves.
{"title":"Coupled dynamic analysis of moored floating structures by a hybrid Laplace-time domain method","authors":"Wei Tao , Jinwei Sun , Shuqing Wang , Shixuan Liu , Linqiang Zhang , Yunming Han","doi":"10.1016/j.oceaneng.2024.120022","DOIUrl":"10.1016/j.oceaneng.2024.120022","url":null,"abstract":"<div><div>The coupled dynamic analysis of moored floating structures has often been conducted in the time domain by iteratively solving the Cummins equation, treating the mooring effects as an additional nonlinear load. However, the time domain (TD) method requires performing a convolution integral at each time step, which is costly in computational time. This paper innovatively develops an efficient hybrid Laplace-time domain method (HLTD) on implementing the coupled dynamic analysis of moored floating structures. The proposed method divides the external load into a number of segments and models the mooring system by the catenary theory. Under each segment, while the iterative operations used in the TD method is borrowed to handle the coupled behavior, the HLTD method computes the motions of the floating structure under each iteration by the pole-residue operations in the Laplace domain (LD). As the complicated convolutional integral computation required in the TD method is replaced by simple algebraic pole-residue calculations in the complex plane, the HLTD method is more efficient. Additionally, the HLTD method derives analytical response solutions for the moored floating system. Its efficiency and accuracy are demonstrated by comparing with the TD method through a moored float-over barge to irregular waves.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"317 ","pages":"Article 120022"},"PeriodicalIF":4.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143094347","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 : 2025-02-01DOI: 10.1016/j.oceaneng.2024.119943
Xinyi Li , Jijian Lian , Zhaolin Jia , Nan Shao , Yaohua Guo , Haijun Wang , Hao Zhao , Zhichuan Wu , Guanhao Zhang , Weipeng Feng
This paper is based on the measured data of an actual offshore wind power thick-walled concrete multi-compartment bucket foundation (MCBF) successfully penetrated and installed under the construction environment of harsh marine conditions, combined with the actual sinking operation steps, several important stages of the foundation sinking posture in the water are investigated, and proposed a set of in-water sinking posture control strategy and the corresponding engineering recommendations. The field-measured penetration resistance is compared with the undrained shear strength (Su) and cone penetration (CPT) method of introducing the resistance reduction coefficient, and the resistance reduction coefficient is verified by the measured penetration differential pressure. The results show that the foundation total inclination can be effectively levelled by the sinking posture control strategy of the lowest side compartment, the three high side compartments and the mid-compartment exhaust, and by the levelling control strategy of only the highest side compartment and the mid-compartment exhaust during the important stage of the sinking posture. When the thick-walled MCBF is sunk to within 1m from the mud surface during high wind and wave conditions, the levelling control strategy is adopted to ensure that the total inclination is within 0.5° when contacting the mud. Before the top cover of the foundation entering the water, the beam structure should be evenly flooded and the total inclination should be controlled within 1°, when the foundation is off the bottom of the vessel, the total inclination should be stabilized to within 0.2°. For the thick-walled MCBF, the two methods can accurately predict the penetration resistance and penetration differential pressure when the resistance reduction coefficient is taken as 0.5. The research in this paper provides construction guidance and experience reference for offshore wind power projects of penetration and installation under harsh marine conditions.
{"title":"Study on the posture control strategy of sinking and penetration characteristics of hexagonal thick-walled multi-compartment bucket foundation","authors":"Xinyi Li , Jijian Lian , Zhaolin Jia , Nan Shao , Yaohua Guo , Haijun Wang , Hao Zhao , Zhichuan Wu , Guanhao Zhang , Weipeng Feng","doi":"10.1016/j.oceaneng.2024.119943","DOIUrl":"10.1016/j.oceaneng.2024.119943","url":null,"abstract":"<div><div>This paper is based on the measured data of an actual offshore wind power thick-walled concrete multi-compartment bucket foundation (MCBF) successfully penetrated and installed under the construction environment of harsh marine conditions, combined with the actual sinking operation steps, several important stages of the foundation sinking posture in the water are investigated, and proposed a set of in-water sinking posture control strategy and the corresponding engineering recommendations. The field-measured penetration resistance is compared with the undrained shear strength (<em>S</em><sub>u</sub>) and cone penetration (CPT) method of introducing the resistance reduction coefficient, and the resistance reduction coefficient is verified by the measured penetration differential pressure. The results show that the foundation total inclination can be effectively levelled by the sinking posture control strategy of the lowest side compartment, the three high side compartments and the mid-compartment exhaust, and by the levelling control strategy of only the highest side compartment and the mid-compartment exhaust during the important stage of the sinking posture. When the thick-walled MCBF is sunk to within 1m from the mud surface during high wind and wave conditions, the levelling control strategy is adopted to ensure that the total inclination is within 0.5° when contacting the mud. Before the top cover of the foundation entering the water, the beam structure should be evenly flooded and the total inclination should be controlled within 1°, when the foundation is off the bottom of the vessel, the total inclination should be stabilized to within 0.2°. For the thick-walled MCBF, the two methods can accurately predict the penetration resistance and penetration differential pressure when the resistance reduction coefficient is taken as 0.5. The research in this paper provides construction guidance and experience reference for offshore wind power projects of penetration and installation under harsh marine conditions.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"317 ","pages":"Article 119943"},"PeriodicalIF":4.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143094269","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}
At present, there are fewer researches on the synergistic drag reduction of microgroove surface and mucus, and there are problems such as unclear drag reduction mechanism, mismatch between surface structure and actual working conditions, which makes the drag reduction effect unsatisfactory and the practical application difficult. On the basis of the previous research of this group, the inclined groove wall surface and curved groove wall surface are selected, and the polyethylene glycol monomethyl ether solution is selected as the bionic mucus through the performance comparison. Accordingly, a hydrodynamic model is established and analysed through numerical simulation to derive the change process of the vortex structure, and reveal the drag reduction mechanism based on its evolution law and drag size. The water hole test platform was built, and the force sensor was placed at the back of the experiment to measure the wall friction resistance of the specimen in the water flow. By changing the velocity of water flow and the secretion rate of bionic mucus, the influence of both on the drag reduction rate is investigated. Both the simulation results and the experimental results show that the resistance reduction rate of the two grooves increases with the increase of the mucus secretion rate, and the maximum value of the resistance reduction is reached when the mucus is discharged at a rate of 0.04 m/s when the water flow velocity is 1 m/s and 2 m/s. The synergistic drag reduction mechanism of microgrooves and mucus is concluded, i.e., microgrooves and mucus change the distribution and density of vortex structure in the boundary layer, and with the increase of mucus velocity, the shape of vortex structure becomes coarse and not easy to be intertwined, which effectively reduces the intensity of turbulence bursts, and reduces the drag reduction rate to a higher level.
{"title":"Optimization of surface microgrooves and their performance and mechanism of synergistic drag reduction with bionic mucus","authors":"Kaisheng Zhang , Jing Li , Kaizhen Zhang , Jing Zhang","doi":"10.1016/j.oceaneng.2024.120029","DOIUrl":"10.1016/j.oceaneng.2024.120029","url":null,"abstract":"<div><div>At present, there are fewer researches on the synergistic drag reduction of microgroove surface and mucus, and there are problems such as unclear drag reduction mechanism, mismatch between surface structure and actual working conditions, which makes the drag reduction effect unsatisfactory and the practical application difficult. On the basis of the previous research of this group, the inclined groove wall surface and curved groove wall surface are selected, and the polyethylene glycol monomethyl ether solution is selected as the bionic mucus through the performance comparison. Accordingly, a hydrodynamic model is established and analysed through numerical simulation to derive the change process of the vortex structure, and reveal the drag reduction mechanism based on its evolution law and drag size. The water hole test platform was built, and the force sensor was placed at the back of the experiment to measure the wall friction resistance of the specimen in the water flow. By changing the velocity of water flow and the secretion rate of bionic mucus, the influence of both on the drag reduction rate is investigated. Both the simulation results and the experimental results show that the resistance reduction rate of the two grooves increases with the increase of the mucus secretion rate, and the maximum value of the resistance reduction is reached when the mucus is discharged at a rate of 0.04 m/s when the water flow velocity is 1 m/s and 2 m/s. The synergistic drag reduction mechanism of microgrooves and mucus is concluded, i.e., microgrooves and mucus change the distribution and density of vortex structure in the boundary layer, and with the increase of mucus velocity, the shape of vortex structure becomes coarse and not easy to be intertwined, which effectively reduces the intensity of turbulence bursts, and reduces the drag reduction rate to a higher level.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"317 ","pages":"Article 120029"},"PeriodicalIF":4.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143094272","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 : 2025-02-01DOI: 10.1016/j.oceaneng.2024.120052
Bin Liu , Lei Zhang , Anyu Liu , C. Guedes Soares
Glass fibre-reinforced polymer (GFRP) hat-stiffened panels have been widely used in high-speed vessels. Using carbon fibre-reinforced polymer (CFRP) as hybrid composites can improve structural stiffness and strength by adopting reasonable material design methods. To show the advantages of the designability of composite materials, the integrated design of materials and structures has to be adopted. This paper establishes the multiscale analysis framework to assess the ultimate strength of marine carbon/glass fibre-reinforced hybrid composite hat-stiffened panels with diverse composite designability. The equivalent material properties at the meso-scale obtained by a multiscale method define the macro-scale ultimate strength in finite element analyses. The investigation is focused on integrating material and structural design variables to optimise the ultimate strength of marine hat-stiffened panels. The response surface method is used to establish a surrogate model of the ultimate strength of marine hat-stiffened panels, and the multi-objective optimisation design is performed using Non-dominated Sorted Genetic Algorithm - II (NSGA-II) with structural mass and ultimate load as optimisation objective functions. The analysis procedure provides the integrated design method of materials and structures to achieve the optimal design of composite stiffened structures.
{"title":"Integrated design method of marine C/GFRP hat-stiffened panels towards ultimate strength optimisation","authors":"Bin Liu , Lei Zhang , Anyu Liu , C. Guedes Soares","doi":"10.1016/j.oceaneng.2024.120052","DOIUrl":"10.1016/j.oceaneng.2024.120052","url":null,"abstract":"<div><div>Glass fibre-reinforced polymer (GFRP) hat-stiffened panels have been widely used in high-speed vessels. Using carbon fibre-reinforced polymer (CFRP) as hybrid composites can improve structural stiffness and strength by adopting reasonable material design methods. To show the advantages of the designability of composite materials, the integrated design of materials and structures has to be adopted. This paper establishes the multiscale analysis framework to assess the ultimate strength of marine carbon/glass fibre-reinforced hybrid composite hat-stiffened panels with diverse composite designability. The equivalent material properties at the meso-scale obtained by a multiscale method define the macro-scale ultimate strength in finite element analyses. The investigation is focused on integrating material and structural design variables to optimise the ultimate strength of marine hat-stiffened panels. The response surface method is used to establish a surrogate model of the ultimate strength of marine hat-stiffened panels, and the multi-objective optimisation design is performed using Non-dominated Sorted Genetic Algorithm - II (NSGA-II) with structural mass and ultimate load as optimisation objective functions. The analysis procedure provides the integrated design method of materials and structures to achieve the optimal design of composite stiffened structures.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"317 ","pages":"Article 120052"},"PeriodicalIF":4.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143094274","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 : 2025-02-01DOI: 10.1016/j.oceaneng.2024.120027
Heri Setiawan , Ke Zheng , Kevin , Jason P. Monty
Particle Image Velocimetry (PIV) measurements were performed in a wind-wave facility to characterise the ship air-wake on the landing deck (LD) of a stationary NATO-GD model. To our knowledge, this is the first laboratory ship air-wake experiment in a naturally-developed boundary layer over a water surface. This study builds on our previous wind tunnel tests over a solid floor (Setiawan et al. 2022, Ocean Engineering, vol. 260, 111931). The results indicate that the air-wake statistical characteristics are comparable to the wind tunnel data, with the mean flow and turbulence kinetic energy only differing by 5% and 2%, respectively, from the flat-plate baseline flow. We further developed a new probabilistic method to estimate the “landing risk” percentage based on the likelihood of extreme turbulence events. Although the exercise was performed using the local vertical wind fluctuations employing a threshold specified for civil aviation, the approach can be adapted for other metrics or can employ a more suitable limit for the Navy context. In essence, we mapped the fractional time (out of the total PIV snapshots) when the exceeded the selected threshold. Having shown Reynolds number independence, we scaled up the velocity data in order to emulate a set of higher reference velocities. It is shown there is a non-linear increase in the “landing risk” percentage with increasing reference velocity (wind speed), and the various inflow conditions affect landing risk.
{"title":"A probabilistic framework for assessing helicopter landing conditions within the ship air-wake","authors":"Heri Setiawan , Ke Zheng , Kevin , Jason P. Monty","doi":"10.1016/j.oceaneng.2024.120027","DOIUrl":"10.1016/j.oceaneng.2024.120027","url":null,"abstract":"<div><div>Particle Image Velocimetry (PIV) measurements were performed in a wind-wave facility to characterise the ship air-wake on the landing deck (LD) of a stationary NATO-GD model. To our knowledge, this is the first laboratory ship air-wake experiment in a naturally-developed boundary layer over a water surface. This study builds on our previous wind tunnel tests over a solid floor (Setiawan et al. 2022, <em>Ocean Engineering</em>, vol. 260, 111931). The results indicate that the air-wake statistical characteristics are comparable to the wind tunnel data, with the mean flow and turbulence kinetic energy only differing by 5% and 2%, respectively, from the flat-plate baseline flow. We further developed a new probabilistic method to estimate the “landing risk” percentage based on the likelihood of extreme turbulence events. Although the exercise was performed using the local vertical wind fluctuations <span><math><msub><mrow><mrow><mo>〈</mo><msub><mrow><mi>σ</mi></mrow><mrow><mi>w</mi><mi>n</mi></mrow></msub><mo>〉</mo></mrow></mrow><mrow><mi>L</mi><mi>D</mi></mrow></msub></math></span> employing a threshold specified for civil aviation, the approach can be adapted for other metrics or can employ a more suitable limit for the Navy context. In essence, we mapped the fractional time (out of the total PIV snapshots) when the <span><math><msub><mrow><mrow><mo>〈</mo><msub><mrow><mi>σ</mi></mrow><mrow><mi>w</mi><mi>n</mi></mrow></msub><mo>〉</mo></mrow></mrow><mrow><mi>L</mi><mi>D</mi></mrow></msub></math></span> exceeded the selected threshold. Having shown Reynolds number independence, we scaled up the velocity data in order to emulate a set of higher reference velocities. It is shown there is a non-linear increase in the “landing risk” percentage with increasing reference velocity (wind speed), and the various inflow conditions affect landing risk.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"317 ","pages":"Article 120027"},"PeriodicalIF":4.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143094281","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 : 2025-02-01DOI: 10.1016/j.oceaneng.2024.119781
Madhulika Bhati, Floris Goerlandt, Ronald Pelot
Digital Twin (DT) technology plays a crucial role in the modernization and optimization of numerous industrial sectors. The blue economy encompasses established sectors such as marine energy systems, shipbuilding and operation, aquaculture and fisheries, and emerging areas including coastal protection and deep-sea mining. Many of these sectors are crucial for attaining Sustainable Development Goals (SDGs), especially pertaining to climate action and marine biodiversity. The integration of DT technologies within the blue economy can offer added value by enhancing operational efficiency, improving risk management, and fostering sustainable practices. This paper uses bibliometric research methods to provide a state-of-the-art overview of this research area. Insights are obtained through several bibliometric indicators, including publication trends, country-based distribution patterns of scholarly communications, and research impact through citation analysis. Keyword co-occurrence analysis is carried out to identify key research themes within the main blue economy sectors. This analysis will enable the research community to understand the key research themes, trends, major research hotspots, and influential works to provides a foundation for innovation, efficiency, and sustainability, benefiting researchers and industry actors. Additionally, it provides policy makers with evidence-based insights crucial for crafting informed policies that promote sustainable development within the blue economy.
{"title":"Digital twin development towards integration into blue economy: A bibliometric analysis","authors":"Madhulika Bhati, Floris Goerlandt, Ronald Pelot","doi":"10.1016/j.oceaneng.2024.119781","DOIUrl":"10.1016/j.oceaneng.2024.119781","url":null,"abstract":"<div><div>Digital Twin (DT) technology plays a crucial role in the modernization and optimization of numerous industrial sectors. The blue economy encompasses established sectors such as marine energy systems, shipbuilding and operation, aquaculture and fisheries, and emerging areas including coastal protection and deep-sea mining. Many of these sectors are crucial for attaining Sustainable Development Goals (SDGs), especially pertaining to climate action and marine biodiversity. The integration of DT technologies within the blue economy can offer added value by enhancing operational efficiency, improving risk management, and fostering sustainable practices. This paper uses bibliometric research methods to provide a state-of-the-art overview of this research area. Insights are obtained through several bibliometric indicators, including publication trends, country-based distribution patterns of scholarly communications, and research impact through citation analysis. Keyword co-occurrence analysis is carried out to identify key research themes within the main blue economy sectors. This analysis will enable the research community to understand the key research themes, trends, major research hotspots, and influential works to provides a foundation for innovation, efficiency, and sustainability, benefiting researchers and industry actors. Additionally, it provides policy makers with evidence-based insights crucial for crafting informed policies that promote sustainable development within the blue economy.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"317 ","pages":"Article 119781"},"PeriodicalIF":4.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143094345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.oceaneng.2024.119980
Wendian Shi , Gang Yang , Haichuan Tian , Lu Lu
Autonomous underwater vehicles (AUV) have been widely used in underwater missions. The motion model of AUV is affected by factors such as parameter uncertainty and disturbances from ocean environment. How to accurately track trajectories under unknown disturbances is a crucial issue. In this paper, an adaptive multivariable super-twisting algorithm (AMSTA) with a nonlinear extended state observer (NLESO) is developed for autonomous underwater vehicles (AUV) to reduce the trajectory tracking error and address the problem of unknown disturbance. First, a novel finite-time extended state observer is designed to estimate and compensate the uncertain nonlinear disturbance. Second, this research presents an improved adaptive multivariable super-twisting algorithm via Lyapunov theory to address the trajectory tracking problem. Finally, simulation results demonstrated the effectiveness and superiority of the proposed scheme.
{"title":"Adaptive multivariable super-twisting algorithm for trajectory tracking of AUV under unknown disturbances","authors":"Wendian Shi , Gang Yang , Haichuan Tian , Lu Lu","doi":"10.1016/j.oceaneng.2024.119980","DOIUrl":"10.1016/j.oceaneng.2024.119980","url":null,"abstract":"<div><div>Autonomous underwater vehicles (AUV) have been widely used in underwater missions. The motion model of AUV is affected by factors such as parameter uncertainty and disturbances from ocean environment. How to accurately track trajectories under unknown disturbances is a crucial issue. In this paper, an adaptive multivariable super-twisting algorithm (AMSTA) with a nonlinear extended state observer (NLESO) is developed for autonomous underwater vehicles (AUV) to reduce the trajectory tracking error and address the problem of unknown disturbance. First, a novel finite-time extended state observer is designed to estimate and compensate the uncertain nonlinear disturbance. Second, this research presents an improved adaptive multivariable super-twisting algorithm via Lyapunov theory to address the trajectory tracking problem. Finally, simulation results demonstrated the effectiveness and superiority of the proposed scheme.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"317 ","pages":"Article 119980"},"PeriodicalIF":4.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143094277","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 : 2025-02-01DOI: 10.1016/j.oceaneng.2024.120046
Biao Song , Qinghua Zhou , Rui Chang
The motion response of Floating Offshore Wind Turbine (FOWT) is a critical factor that significantly impacts the safety of offshore wind energy systems. Accurate prediction of these responses is essential for selecting appropriate operation and maintenance strategies. In order to improve the prediction accuracy, this study proposes an innovative time-frequency (TF) feature fusion algorithm and combines it with empirical mode decomposition (EMD), empirical wavelet transform (EWT), and long-short-term memory (LSTM) to develop a novel hybrid prediction model named EMD-EWT-TF-LSTM. Numerical data of platform motion response of a 15 MW FOWT under marine environmental loads are employed for model training and validation. The prediction performance of the TF-LSTM and EMD-TF-LSTM models developed based on the time-frequency feature fusion algorithm is compared with that of the traditional models (LSTM, EMD-LSTM), and the results show that the proposed algorithms can effectively improve the prediction accuracy. Furthermore, an improved EMD-EWT-TF-LSTM model is proposed to solve the problem of the overall prediction accuracy degradation due to the insufficient prediction performance of the high-frequency components in the EMD decomposition results. This study demonstrates that the proposed EMD-EWT-TF-LSTM model is effective for predicting the motion response of FOWT under various sea states. In comparison to the conventional EMD-LSTM model, the prediction accuracy of the EMD-EWT-TF-LSTM model has increased by 29.3% in normal sea conditions and 21.7% in extreme sea conditions.
{"title":"Short-term motion prediction of FOWT based on time-frequency feature fusion LSTM combined with signal decomposition methods","authors":"Biao Song , Qinghua Zhou , Rui Chang","doi":"10.1016/j.oceaneng.2024.120046","DOIUrl":"10.1016/j.oceaneng.2024.120046","url":null,"abstract":"<div><div>The motion response of Floating Offshore Wind Turbine (FOWT) is a critical factor that significantly impacts the safety of offshore wind energy systems. Accurate prediction of these responses is essential for selecting appropriate operation and maintenance strategies. In order to improve the prediction accuracy, this study proposes an innovative time-frequency (TF) feature fusion algorithm and combines it with empirical mode decomposition (EMD), empirical wavelet transform (EWT), and long-short-term memory (LSTM) to develop a novel hybrid prediction model named EMD-EWT-TF-LSTM. Numerical data of platform motion response of a 15 MW FOWT under marine environmental loads are employed for model training and validation. The prediction performance of the TF-LSTM and EMD-TF-LSTM models developed based on the time-frequency feature fusion algorithm is compared with that of the traditional models (LSTM, EMD-LSTM), and the results show that the proposed algorithms can effectively improve the prediction accuracy. Furthermore, an improved EMD-EWT-TF-LSTM model is proposed to solve the problem of the overall prediction accuracy degradation due to the insufficient prediction performance of the high-frequency components in the EMD decomposition results. This study demonstrates that the proposed EMD-EWT-TF-LSTM model is effective for predicting the motion response of FOWT under various sea states. In comparison to the conventional EMD-LSTM model, the prediction accuracy of the EMD-EWT-TF-LSTM model has increased by 29.3% in normal sea conditions and 21.7% in extreme sea conditions.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"317 ","pages":"Article 120046"},"PeriodicalIF":4.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143094278","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 : 2025-02-01DOI: 10.1016/j.oceaneng.2024.120090
Mahdi Shahidikhah, Majid Moradi, Alireza Bateni, Abbas Ghalandarzadeh
This study investigates the impact of monopile dimensions on the seismic response of offshore wind turbines (OWTs), considering soil-water-structure interaction (SWSI). During earthquakes, OWTs may experience critical conditions, leading to operational shutdowns due to structural responses such as high acceleration, permanent rotation, and displacement. Key factors influencing seismic response include monopile diameter, driven length, and hybrid monopile designs, which are the main focus of this research. Eight physical models were constructed: one baseline model, two with modified monopile diameters, two with altered driven lengths, and three hybrid monopile models featuring shallow wheels of varying diameters. These models were tested under 1g conditions and on a shaking table with nine sinusoidal motions at three frequencies and three amplitudes, simulating saturated soil conditions. The pore water pressure generation, soil and superstructure acceleration, and displacement were monitored during each test. The results show that increasing the monopile's driven length reduces the superstructure's cumulative displacement and improves overall seismic performance. Moreover, increasing the monopile diameter or adding shallow wheels to create a hybrid monopile increases pore water pressure, which in turn results in greater cumulative displacement of the OWT.
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