Abstract In the field of ocean engineering, the task of spatial hull modelling is one of the most complicated problems in ship design. This study presents a procedure applied as a generative approach to the design problems for the hull geometry of small vessels using elements of concurrent design with multi-criteria optimisation processes. Based upon widely available commercial software, an algorithm for the mathematical formulation of the boundary conditions, the data flow during processing and formulae for the optimisation processes are developed. As an example of the application of this novel approach, the results for the hull design of a sailing yacht are presented.
{"title":"A Generative Approach to Hull Design for a Small Watercraft","authors":"A. Karczewski, J. Kozák","doi":"10.2478/pomr-2023-0001","DOIUrl":"https://doi.org/10.2478/pomr-2023-0001","url":null,"abstract":"Abstract In the field of ocean engineering, the task of spatial hull modelling is one of the most complicated problems in ship design. This study presents a procedure applied as a generative approach to the design problems for the hull geometry of small vessels using elements of concurrent design with multi-criteria optimisation processes. Based upon widely available commercial software, an algorithm for the mathematical formulation of the boundary conditions, the data flow during processing and formulae for the optimisation processes are developed. As an example of the application of this novel approach, the results for the hull design of a sailing yacht are presented.","PeriodicalId":49681,"journal":{"name":"Polish Maritime Research","volume":"30 1","pages":"4 - 12"},"PeriodicalIF":2.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46540880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Marine centrifugal fans usually work in harsh environments. Their vibration signals are non-linear. The traditional fault diagnosis methods of fans require much calculation and have low operating efficiency. Only shallow fault features can be extracted. As a result, the diagnosis accuracy is not high. It is difficult to realize the end-to-end fault diagnosis. Combining the Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (CEEMDAN) and lightweight neural network, a fault classification method is proposed. First, the CEEMDAN can decompose the vibration signal into several intrinsic modal functions (IMF). Then, the original signals can be transformed into 2-D images through pseudo-colour coding of the IMFs. Finally, they are fed into the lightweight neural network for fault diagnosis. By embedding a convolutional block attention module (CBAM), the ability of the network to extract critical feature information is improved. The results show that the proposed method can adaptively extract the fault characteristics of a marine centrifugal fan. While the model is lightweight, the overall diagnostic accuracy can reach 99.3%. As exploratory basic research, this method can provide a reference for intelligent fault diagnosis systems on ships.
{"title":"Deep Learning-Based Fault Diagnosis for Marine Centrifugal Fan","authors":"Congyue Li, Yihuai Hu, Jiawei Jiang, Guo Yan","doi":"10.2478/pomr-2023-0011","DOIUrl":"https://doi.org/10.2478/pomr-2023-0011","url":null,"abstract":"Abstract Marine centrifugal fans usually work in harsh environments. Their vibration signals are non-linear. The traditional fault diagnosis methods of fans require much calculation and have low operating efficiency. Only shallow fault features can be extracted. As a result, the diagnosis accuracy is not high. It is difficult to realize the end-to-end fault diagnosis. Combining the Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (CEEMDAN) and lightweight neural network, a fault classification method is proposed. First, the CEEMDAN can decompose the vibration signal into several intrinsic modal functions (IMF). Then, the original signals can be transformed into 2-D images through pseudo-colour coding of the IMFs. Finally, they are fed into the lightweight neural network for fault diagnosis. By embedding a convolutional block attention module (CBAM), the ability of the network to extract critical feature information is improved. The results show that the proposed method can adaptively extract the fault characteristics of a marine centrifugal fan. While the model is lightweight, the overall diagnostic accuracy can reach 99.3%. As exploratory basic research, this method can provide a reference for intelligent fault diagnosis systems on ships.","PeriodicalId":49681,"journal":{"name":"Polish Maritime Research","volume":"30 1","pages":"112 - 120"},"PeriodicalIF":2.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46140159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Underwater localization and tracking is a challenging problem and Time-of-Arrival and Time-Difference-of-Arrival approaches are commonly used. However, the performance difference between these approaches is not well understood or analysed adequately. There are some analytical studies for terrestrial applications with the assumption that the signal arrival times are not correlated. However, this assumption is not valid for underwater propagation. To present the distinct nature of the problem under the water, a high-fidelity simulation is required. In this study, Time-of-Arrival and Time-Difference-of-Arrival approaches are compared using a ray tracing based propagation model. Moreover, basic methods to mitigate the multipath propagation problem are also implemented for Bernoulli filters. Since the Bernoulli filter is a joint detection and tracking filter, the detection performance is also analysed. Comparisons are done for all combinations of filter and measurement approaches. The results can help to design underwater localization systems better suited to the needs.
{"title":"Performance Comparison of ToA and TDOA Based Tracking In Underwater Multipath Environments Using Bernoulli Filter","authors":"A. Gunes","doi":"10.2478/pomr-2023-0014","DOIUrl":"https://doi.org/10.2478/pomr-2023-0014","url":null,"abstract":"Abstract Underwater localization and tracking is a challenging problem and Time-of-Arrival and Time-Difference-of-Arrival approaches are commonly used. However, the performance difference between these approaches is not well understood or analysed adequately. There are some analytical studies for terrestrial applications with the assumption that the signal arrival times are not correlated. However, this assumption is not valid for underwater propagation. To present the distinct nature of the problem under the water, a high-fidelity simulation is required. In this study, Time-of-Arrival and Time-Difference-of-Arrival approaches are compared using a ray tracing based propagation model. Moreover, basic methods to mitigate the multipath propagation problem are also implemented for Bernoulli filters. Since the Bernoulli filter is a joint detection and tracking filter, the detection performance is also analysed. Comparisons are done for all combinations of filter and measurement approaches. The results can help to design underwater localization systems better suited to the needs.","PeriodicalId":49681,"journal":{"name":"Polish Maritime Research","volume":"30 1","pages":"135 - 144"},"PeriodicalIF":2.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45057690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Le, Nguyen Duy Anh, T. Tu, Nguyen Thi Ngoc Hoa, Vu Minh Ngoc
Abstract The paper discusses the length to beam (L/B) ratio effects on ship resistance at three different Froude numbers using unsteady RANSE simulation. First, the JBC ship model was used as an initial hull form for verification and validation of predicted ship resistance results with measured data, and then the influence of the L/B ratio on ship resistance was carried out. Ship hull forms with different L/B ratios were produced from the initial one by using the Lackenby method. The numerical results obtained show the L/B ratio’s effect on ship resistance. Increases of the L/B ratio led to gradual reduction of the total ship resistance and vice versa. Analysis of the changing of the resistance components indicates that the pressure resistance changes are considerably larger than the frictional one. Finally, the paper analyses the difference in the flow field around the hull of the ship with variation of the L/B ratio to fully understand the physical phenomenon in the change of ship resistance at different L/B parameters.
{"title":"Numerical Investigation of Length to Beam Ratio Effects on Ship Resistance Using Ranse Method","authors":"T. Le, Nguyen Duy Anh, T. Tu, Nguyen Thi Ngoc Hoa, Vu Minh Ngoc","doi":"10.2478/pomr-2023-0002","DOIUrl":"https://doi.org/10.2478/pomr-2023-0002","url":null,"abstract":"Abstract The paper discusses the length to beam (L/B) ratio effects on ship resistance at three different Froude numbers using unsteady RANSE simulation. First, the JBC ship model was used as an initial hull form for verification and validation of predicted ship resistance results with measured data, and then the influence of the L/B ratio on ship resistance was carried out. Ship hull forms with different L/B ratios were produced from the initial one by using the Lackenby method. The numerical results obtained show the L/B ratio’s effect on ship resistance. Increases of the L/B ratio led to gradual reduction of the total ship resistance and vice versa. Analysis of the changing of the resistance components indicates that the pressure resistance changes are considerably larger than the frictional one. Finally, the paper analyses the difference in the flow field around the hull of the ship with variation of the L/B ratio to fully understand the physical phenomenon in the change of ship resistance at different L/B parameters.","PeriodicalId":49681,"journal":{"name":"Polish Maritime Research","volume":"30 1","pages":"13 - 24"},"PeriodicalIF":2.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48522818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Aiming at the challenges to the accurate and stable heading control of underactuated unmanned surface vehicles arising from the nonlinear interference caused by the overlay and the interaction of multi interference, and also the uncertainties of model parameters, a heading control algorithm for an underactuated unmanned surface vehicle based on an improved backpropagation neural network is proposed. Based on applying optimization theory to realize that the underactuated unmanned surface vehicle tracks the desired yaw angle and maintains it, the improved momentum of weight is combined with an improved tracking differentiator to improve the robustness of the system and the dynamic property of the control. A hyperbolic tangent function is used to establish the nonlinear mappings an approximate method is adopted to summarize the general mathematical expressions, and the gradient descent method is applied to ensure the convergence. The simulation results show that the proposed algorithm has the advantages of strong robustness, strong anti-interference and high control accuracy. Compared with two commonly used heading control algorithms, the accuracy of the heading control in the complex environment of the proposed algorithm is improved by more than 50%.
{"title":"Adptive Heading Control of Underactuated Unmanned Surface Vehicle Based on Improved Backpropagation Neural Network","authors":"Zaopeng Dong, Jiakang Li, W. Liu, Haisheng Zhang, Shijie Qi, Zheng Zhang","doi":"10.2478/pomr-2023-0006","DOIUrl":"https://doi.org/10.2478/pomr-2023-0006","url":null,"abstract":"Abstract Aiming at the challenges to the accurate and stable heading control of underactuated unmanned surface vehicles arising from the nonlinear interference caused by the overlay and the interaction of multi interference, and also the uncertainties of model parameters, a heading control algorithm for an underactuated unmanned surface vehicle based on an improved backpropagation neural network is proposed. Based on applying optimization theory to realize that the underactuated unmanned surface vehicle tracks the desired yaw angle and maintains it, the improved momentum of weight is combined with an improved tracking differentiator to improve the robustness of the system and the dynamic property of the control. A hyperbolic tangent function is used to establish the nonlinear mappings an approximate method is adopted to summarize the general mathematical expressions, and the gradient descent method is applied to ensure the convergence. The simulation results show that the proposed algorithm has the advantages of strong robustness, strong anti-interference and high control accuracy. Compared with two commonly used heading control algorithms, the accuracy of the heading control in the complex environment of the proposed algorithm is improved by more than 50%.","PeriodicalId":49681,"journal":{"name":"Polish Maritime Research","volume":"30 1","pages":"54 - 64"},"PeriodicalIF":2.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47574889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The article addresses the three-dimensional (3D) underwater path planning problem of an autonomous underwater vehicle (AUV) in a time-varying current. A modified artificial potential field algorithm combining the velocity vector synthesis method is proposed to search for the optimal path. The modified potential field (MPF) algorithm is designed to dynamically plan the non-collision path. Meanwhile, this modified method is also proved to be an effective solution to the goals not reachable with obstacles nearby (GNRON), U-shaped trap, and rotation unreachable problems. To offset the influence of time-varying current, the velocity synthesis approach is designed to adjust the AUV movement direction. Besides, considering path planning in the complex underwater environment, the multi-beam forward-looking sonar (FLS) model is used. Finally, simulation studies substantiate that the designed algorithm can implement the AUV path planning effectively and successfully in a 3D underwater environment.
{"title":"Three-Dimensional Underwater Path Planning Based on Modified Potential Field Algorithm in Time-Varying Current","authors":"Shasha Wang, Guilin Feng, Dan Wang, Yulong Tuo","doi":"10.2478/pomr-2023-0004","DOIUrl":"https://doi.org/10.2478/pomr-2023-0004","url":null,"abstract":"Abstract The article addresses the three-dimensional (3D) underwater path planning problem of an autonomous underwater vehicle (AUV) in a time-varying current. A modified artificial potential field algorithm combining the velocity vector synthesis method is proposed to search for the optimal path. The modified potential field (MPF) algorithm is designed to dynamically plan the non-collision path. Meanwhile, this modified method is also proved to be an effective solution to the goals not reachable with obstacles nearby (GNRON), U-shaped trap, and rotation unreachable problems. To offset the influence of time-varying current, the velocity synthesis approach is designed to adjust the AUV movement direction. Besides, considering path planning in the complex underwater environment, the multi-beam forward-looking sonar (FLS) model is used. Finally, simulation studies substantiate that the designed algorithm can implement the AUV path planning effectively and successfully in a 3D underwater environment.","PeriodicalId":49681,"journal":{"name":"Polish Maritime Research","volume":"30 1","pages":"33 - 42"},"PeriodicalIF":2.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49387832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The development of IoT (the Internet of Things) wireless transmission opens a new era in communication systems. In the next years, the development and implementation of IoT systems will be very dynamic. It can be seen that the solutions of LTE – NB-IoT (Long Term Evolution – Narrowband IoT) transmission devices are implemented in a wide range of terrestrial solutions, e.g. smart grids. This paper aims to analyse the possibility of the use of NB-IoT technology for maritime communication applications and partially, for some maritime safety solutions, based on signal coverage analysis at sea. An interesting approach is the comparison of the results of NB-IoT coverage to the classic cellular LTE-based communication systems. Proposed solutions are based on the practical implementation of a designed specialised data concentrator with implemented gateway and radio modems, for both NB-IoT technology as well as LTE. In the paper, analyses of radio link budget and propagation loss models for sea environment are presented. The coverage analysis is based on real measurements of the efficiency of transmissions using wireless modems implemented in the developed data concentrator.
物联网(IoT)无线传输的发展开启了通信系统的新时代。未来几年，物联网系统的开发和实施将是非常动态的。可以看出，LTE - NB-IoT (Long Term Evolution -窄带物联网)传输设备的解决方案在广泛的地面解决方案中实现，例如智能电网。本文旨在分析在海上通信应用中使用NB-IoT技术的可能性，以及基于海上信号覆盖分析的部分海上安全解决方案。一个有趣的方法是将NB-IoT覆盖结果与经典的基于蜂窝lte的通信系统进行比较。提出的解决方案基于设计的专用数据集中器的实际实施，该数据集中器具有实现的网关和无线电调制解调器，适用于NB-IoT技术和LTE。本文对海洋环境下的无线电链路预算和传播损耗模型进行了分析。覆盖分析是基于使用所开发的数据集中器中实现的无线调制解调器的传输效率的实际测量。
{"title":"Evaluation of the Use of M2M-Type NB-IoT and LTE Technologies for Maritime Communication Systems","authors":"S. Gajewski, Agnieszka Czapiewska, M. Gajewska","doi":"10.2478/pomr-2023-0013","DOIUrl":"https://doi.org/10.2478/pomr-2023-0013","url":null,"abstract":"Abstract The development of IoT (the Internet of Things) wireless transmission opens a new era in communication systems. In the next years, the development and implementation of IoT systems will be very dynamic. It can be seen that the solutions of LTE – NB-IoT (Long Term Evolution – Narrowband IoT) transmission devices are implemented in a wide range of terrestrial solutions, e.g. smart grids. This paper aims to analyse the possibility of the use of NB-IoT technology for maritime communication applications and partially, for some maritime safety solutions, based on signal coverage analysis at sea. An interesting approach is the comparison of the results of NB-IoT coverage to the classic cellular LTE-based communication systems. Proposed solutions are based on the practical implementation of a designed specialised data concentrator with implemented gateway and radio modems, for both NB-IoT technology as well as LTE. In the paper, analyses of radio link budget and propagation loss models for sea environment are presented. The coverage analysis is based on real measurements of the efficiency of transmissions using wireless modems implemented in the developed data concentrator.","PeriodicalId":49681,"journal":{"name":"Polish Maritime Research","volume":"30 1","pages":"126 - 134"},"PeriodicalIF":2.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45797266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Dynamic designs for ship propulsion shafting can be categorised as complex multi-disciplinary coupling systems. The traditional single disciplinary optimisation design method has become a bottleneck, restricting the further improvement of shafting design. In this paper, taking a complex propulsion shafting as the object, a dynamic analysis model of the propeller-shafting-hull system was established. In order to analyse the coupling effect of propeller hydrodynamics on shafting dynamics, the propeller’s hydrodynamic force in the wake flow field was calculated as the input for shafting alignment and vibration analysis. On this basis, the discipline decomposition and analysis of the subdisciplines in design of shafting dynamics were carried out. The coupling relationships between design variables in the subdisciplines were studied and the Multi-disciplinary Design Optimisation (MDO) framework of shafting dynamics was established. Finally, taking the hollowness of the shaft segments and the vertical displacement of bearings as design variables, combined with the optimal algorithm, the MDO of shafting dynamics, considering the coupling effect of the propeller-shafting-hull system, was realised. The results presented in this paper can provide a beneficial reference for improving the design quality of ship shafting.
{"title":"Research on MDO of Ship Propulsion Shafting Dynamics Considering the Coupling Effect of a Propeller-Shafting-Hull System","authors":"Jinlin Liu, Zheng Gu, Shuyong Liu","doi":"10.2478/pomr-2023-0009","DOIUrl":"https://doi.org/10.2478/pomr-2023-0009","url":null,"abstract":"Abstract Dynamic designs for ship propulsion shafting can be categorised as complex multi-disciplinary coupling systems. The traditional single disciplinary optimisation design method has become a bottleneck, restricting the further improvement of shafting design. In this paper, taking a complex propulsion shafting as the object, a dynamic analysis model of the propeller-shafting-hull system was established. In order to analyse the coupling effect of propeller hydrodynamics on shafting dynamics, the propeller’s hydrodynamic force in the wake flow field was calculated as the input for shafting alignment and vibration analysis. On this basis, the discipline decomposition and analysis of the subdisciplines in design of shafting dynamics were carried out. The coupling relationships between design variables in the subdisciplines were studied and the Multi-disciplinary Design Optimisation (MDO) framework of shafting dynamics was established. Finally, taking the hollowness of the shaft segments and the vertical displacement of bearings as design variables, combined with the optimal algorithm, the MDO of shafting dynamics, considering the coupling effect of the propeller-shafting-hull system, was realised. The results presented in this paper can provide a beneficial reference for improving the design quality of ship shafting.","PeriodicalId":49681,"journal":{"name":"Polish Maritime Research","volume":"30 1","pages":"86 - 97"},"PeriodicalIF":2.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45095876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract This paper presents a study of a viscous torsional vibration damper for a crankshaft of a four-stroke diesel engine. The reliable operation of a widely used silicone-type viscous damper depends on the ability of the silicone oil to absorb the energy of torsional vibrations. The non-Newtonian shear flow of the silicone oil interlayer, characterised by a reduction in the shear-rate-dependent viscosity and a moment of the drag forces, negatively affects damping characteristics. A torsional vibration damper, filled with a shear-thickening fluid, was considered and a rheological approach, based on viscosity growth with the shear rate increase, was applied. For such a damper, larger velocity gradients correspond to the higher values of a viscous force, which decreases torsional vibration. The parameter of damper effectiveness (defined by the fluid flow index, values of the damper gaps, torsional vibration amplitude and frequency) was implemented. It has been established that the efficiency of the torsional vibration damper filled with a dilatant fluid does not depend on the damper dimensions and gaps and significantly increases when a shear-thickening fluid is used instead of silicone oil or a Newtonian fluid. At higher values of the flow index, when the non-Newtonian flow becomes distinct, torsional vibrations are damped more effectively. Critical vibration amplitudes at high-velocity gradients, in turn, increase the damping effect as the moment of the drag forces and flow index are power-law related.
{"title":"Dilatant-Fluid Torsional Vibration Damper for a Four-Stroke Diesel Engine Crankshaft","authors":"S. Kozytskyi, S.V. Kiriian","doi":"10.2478/pomr-2023-0012","DOIUrl":"https://doi.org/10.2478/pomr-2023-0012","url":null,"abstract":"Abstract This paper presents a study of a viscous torsional vibration damper for a crankshaft of a four-stroke diesel engine. The reliable operation of a widely used silicone-type viscous damper depends on the ability of the silicone oil to absorb the energy of torsional vibrations. The non-Newtonian shear flow of the silicone oil interlayer, characterised by a reduction in the shear-rate-dependent viscosity and a moment of the drag forces, negatively affects damping characteristics. A torsional vibration damper, filled with a shear-thickening fluid, was considered and a rheological approach, based on viscosity growth with the shear rate increase, was applied. For such a damper, larger velocity gradients correspond to the higher values of a viscous force, which decreases torsional vibration. The parameter of damper effectiveness (defined by the fluid flow index, values of the damper gaps, torsional vibration amplitude and frequency) was implemented. It has been established that the efficiency of the torsional vibration damper filled with a dilatant fluid does not depend on the damper dimensions and gaps and significantly increases when a shear-thickening fluid is used instead of silicone oil or a Newtonian fluid. At higher values of the flow index, when the non-Newtonian flow becomes distinct, torsional vibrations are damped more effectively. Critical vibration amplitudes at high-velocity gradients, in turn, increase the damping effect as the moment of the drag forces and flow index are power-law related.","PeriodicalId":49681,"journal":{"name":"Polish Maritime Research","volume":"30 1","pages":"121 - 125"},"PeriodicalIF":2.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46416430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract A consistent approach to the development of tuning rules for course-keeping and path-tracking PID controllers for a ship autopilot are presented. The consistency comes from the observation that for each of the controllers the controlled plant can be modelled by an integrator with inertia. In the case of the course controller, it is the well-known Nomoto model. The PID controller may be implemented in series or parallel form, the consequence of which is a 2nd or 3rd order of the system, specified by a double or triple closed-loop time constant. The new tuning rules may be an alternative to the standard ones given in [1,2]. It is shown that, whereas the reference responses for the standard and new rules are almost the same, the new rules provide better suppression of disturbances such as wind, waves or current. The parallel controller is particularly advantageous. The path-tracking PID controller can provide better tracking accuracy than the conventional PI. Simulated path-tracking trajectories generated by a cascade control system are presented. The novelty of this research is in the theory, specifically in the development of new tuning rules for the two PID autopilot controllers that improve disturbance suppression.
{"title":"Consistent Design of PID Controllers for an Autopilot","authors":"Z. Świder, L. Trybus, Andrzej Stec","doi":"10.2478/pomr-2023-0008","DOIUrl":"https://doi.org/10.2478/pomr-2023-0008","url":null,"abstract":"Abstract A consistent approach to the development of tuning rules for course-keeping and path-tracking PID controllers for a ship autopilot are presented. The consistency comes from the observation that for each of the controllers the controlled plant can be modelled by an integrator with inertia. In the case of the course controller, it is the well-known Nomoto model. The PID controller may be implemented in series or parallel form, the consequence of which is a 2nd or 3rd order of the system, specified by a double or triple closed-loop time constant. The new tuning rules may be an alternative to the standard ones given in [1,2]. It is shown that, whereas the reference responses for the standard and new rules are almost the same, the new rules provide better suppression of disturbances such as wind, waves or current. The parallel controller is particularly advantageous. The path-tracking PID controller can provide better tracking accuracy than the conventional PI. Simulated path-tracking trajectories generated by a cascade control system are presented. The novelty of this research is in the theory, specifically in the development of new tuning rules for the two PID autopilot controllers that improve disturbance suppression.","PeriodicalId":49681,"journal":{"name":"Polish Maritime Research","volume":"30 1","pages":"78 - 85"},"PeriodicalIF":2.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44676799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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