Ship safe navigation visualization method and system based on digital twinning

Abstract

The invention belongs to the technical field of ship navigation simulation, and particularly relates to a ship safe navigation visualization method and system based on digital twinning, and the method comprises the following steps: S1, collecting marine meteorological data, ship host data and ship structure data, and building a ship database; s2, establishing a simulated marine environment model, and simulating a marine water body environment in two modes of data driving and physical model driving; s3, generating a three-dimensional model of the ship through the ship data based on a digital twinning technology, and simulating a navigation state; collected marine meteorological data, ship main engine data and ship structure data are introduced into a three-dimensional model for state prediction, data collected by a real ship are used for comparison verification, and visual output is carried out. Through the constructed ocean model, data of ship navigation and equipment operation can be collected for a long time, the data can be analyzed through the digital twin technology, the equipment failure rate is reduced, and the navigation cost is reduced.

Description

Technical Field

[0001] The present application belongs to the technical field of ship navigation simulation, and specifically relates to a method and system for visualizing safe ship navigation based on digital twins. Background Art

[0002] In recent years, my country's shipbuilding industry has been developing continuously. In the real ship operating environment, there are many complex and unpredictable working conditions. Timely understanding of the ship's navigation environment is the basis for ensuring the safe navigation of ships. At the same time, the structure of the hull itself is relatively complex and the volume is relatively large, so it is relatively difficult to accurately detect it, especially for sea-going ships. Due to the variability and randomness of sea conditions, it will be more difficult to accurately detect them in real time. Summary of the invention

[0003] Based on the above problems, this application constructs a simulated ocean environment model. Through the virtual environment of digital twins, ships can simulate different sailing routes, analyze the impact of wind, waves, ocean currents, weather and other factors on navigation, and improve navigation safety and efficiency. Its technical solution is: A digital twin-based ship safe navigation visualization method includes the following steps: S1. Collect marine meteorological data, ship host data and ship structure data to establish a ship database; S2. Establish a simulated ocean environment model and use data-driven and physical model-driven methods to simulate the ocean water environment; S3. Generate a three-dimensional model of the ship with ship data based on digital twin technology to simulate the navigation status; introduce the collected ocean meteorological data, ship main engine data and ship structure data into the three-dimensional model for status prediction, and use the data collected from the actual ship for comparative verification and visualization output.

[0004] Preferably, in step S1, meteorological sensors and wave sensors are used to collect wind direction, current and wave information in the marine environment, and at the same time, ship main body data is formed through ship host sensors, cameras and stress strain sensors, and the data is transmitted to a data processing server to form a ship main body and marine environment database.

[0005] Preferably, the steps of establishing a simulated ocean environment model are as follows: S21. The kinematic model of the ship is constructed based on the modular concept and the time domain unified model theory, and the formula is as follows: ; Where: is the total force on the hull, , , They represent the forces generated by the hull, propeller, and rudder respectively; , , , Represent the environmental disturbance forces caused by wind, current, first-order wave and second-order wave respectively; the hull force includes the hull radiation force and hydrostatic restoring force matrix calculated by the additional mass matrix A, damping coefficient matrix B and impulse response function matrix and nonlinear viscous forces calculated from the viscous hydrodynamic coefficients ; For time, is the time constant of the change, is the time constant, represents the skewness coefficient; S22. Construct a hydrodynamic coefficient database based on the regression method, and use the database interpolation to calculate the hydrodynamic coefficients of the ship under different motion states in the time domain simulation; S23. Reproduce the real ocean information by numerically solving the ocean environment vector field. The formula is as follows: ; Where: N is the wave action density spectrum; is a two-dimensional Hamiltonian operator; is the group velocity; is the flow rate; and is the wave number and wave direction; s It is the direction A coordinate of is the coordinate perpendicular to the s direction; is the source term of the spectrum, through the linear input term , Wind Input , nonlinear wave interaction term , dissipative term and seafloor friction Combination S24. Establish a real sea area database and a hydrodynamic database for the purpose of reproducing the real ocean environment and predicting the ship motion status.

[0006] Preferably, in step S22, the environmental effects on the ship during navigation mainly come from wind, current and waves, which correspond to , , , , where the sea waves and the wind force on the ship during navigation can be calculated using the wind load coefficient, the expression is as follows: ; In the formula is the air density; is the apparent wind speed; , are the wind load coefficients in the x and y directions, is the wind load factor in any direction, is the wind load coefficient per unit area; is the lateral projection area of ​​the ship; The forward projection area from the ship; is the total length of the ship; since the viscous nonlinear force of the current on the hull has been calculated in the hull force, the ship is disturbed by the current Simplified as a translational motion with the ocean current, as follows: ; In the formula and represents the velocity component of the original current; is the velocity of the original ocean current; is the original flow direction; is the heading of the ship; and is the relative ship speed after vector uniform calculation, is the lateral current velocity, are the longitudinal current velocities, respectively.

[0007] Preferably, the calculation of the wave excitation force is performed based on the first-order wave load response factor and the wave spectrum, and the following is obtained: ; In the formula represents 6 degrees of freedom; is the first-order wave load coefficient corresponding to different degrees of freedom; is the ship speed, is the wave discrete frequency; is the wave encounter angle; For wave height and using wave spectrum , wave discrete frequency and wave diffusion angle calculate; is the random phase in the irregular wave; is the phase value of the wave load coefficient and is calculated from the real and imaginary parts of the wave load coefficient, is the wave discrete frequency increment, is the diffusion angle increment.

[0008] Preferably, the second-order waves produce a slow drift effect on the ship's motion, and the wave drift force is calculated using the second-order wave load coefficient and wave spectrum. Calculate according to the following formula: ; ; Where: is the average second-order wave load coefficient; is the average ship speed in the x-axis direction, is the average ship speed in the y-axis direction, is the average ship speed in any direction, is the discrete wave frequency and wave encounter angle The corresponding second-order load factor in the frequency domain; It is a meaningful wave high; is the density of seawater; is the acceleration due to gravity; It is the length between perpendicular lines of the ship.

[0009] Preferably, in step S3, a digital twin model is constructed : ; PS are physical ship parameters; VS are virtual ship parameters; SS Data simulation: collect physical ship parameters, simulate virtual ships, output physical ship and virtual ship data to the front end; and send simulation results to the historical database DD ; DD For historical database: provide data source for simulation; FD For front-end display: real-time dynamic display of physical and virtual ship headings; CN For data interaction.

[0010] Preferably, data interaction CN The expression is as follows: ; Real-time data collection through data collection PS Data, and transfer the data to the VS corresponding model; Implemented via standard software interface PS and SS Two-way communication, data collection, transmission and storage; Real-time data collection using a variety of sensors, data acquisition devices, and standard / non-standard communication protocols PS Data and transmit to DD ; Implemented via standard software interface VS and SSTwo-way communication to achieve model-driven based on real-time data; Realized through network communication technology VS and FD Real-time synchronization and dynamic interaction; Store real-time data into DD In the meantime SS Through DD Statistical analysis of historical data and support for the use of common algorithms and mathematical models SS Operation; Through TCP / IP, UDP and other network communication technologies SS Supported by FD and DD Data interaction between them; It is realized through interface technology, network communication technology and front-end development technology FD and SS Data interaction between SS for FD Provide interface integration services, data interaction services, and define FD Human-computer interaction responds to decision rules.

[0011] A digital twin-based ship safe navigation visualization system, including a data acquisition module, a data processing module and a data visualization module; The data acquisition module uses sensors to obtain relevant parameter data of the physical ship and builds a historical database; The data processing module: uses the historical database to simulate the virtual ship and outputs the physical ship and virtual ship data to the front end; Data visualization module: physical ship and virtual ship visualization output.

[0012] Preferably, the data visualization module: synchronously displays the ship's navigation route and the ocean water environment, and can intuitively and accurately display the ship's latitude and longitude, heading, attitude, speed, water temperature, water depth, wind speed, wind direction and other data information, as well as the different amplitudes of swaying of the hull itself in different sea conditions, and further simulate the ship's navigation attitude through the established ocean environment model to assist decision-making.

[0013] Compared with the prior art, the present invention has the following beneficial effects: 1) Use data-driven and physical model-driven methods to simulate the ocean water environment, maximize the simulation of the changing ocean environment, get closer to the actual situation, and provide an accurate environmental model for simulation.

[0014] 2) Through the virtual environment of digital twins, ships can simulate different sailing routes, analyze the impact of multiple factors such as wind, waves, ocean currents, and weather on navigation, and improve navigation safety and efficiency.

[0015] 3) Through digital twin models Various real-time data of the ship can be synchronized with the virtual model through sensors and the Internet of Things. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is the flow chart of this application.

[0017] Figure 2 These are simulation diagrams of the additional mass coefficient at different wave encounter angles, including (a) the simulation diagram when the wave encounter angle is 0, (b) the simulation diagram when the wave encounter angle is 60, (c) the simulation diagram when the wave encounter angle is 120, and (d) the simulation diagram when the wave encounter angle is 150.

[0018] Figure 3 Schematic diagram of the digital twin model. DETAILED DESCRIPTION

[0019] The technical solution of the present application is described in detail below through specific embodiments and drawings. It should be understood that the embodiments of the present application and the specific features in the embodiments are detailed descriptions of the technical solution of the present application, rather than limitations on the technical solution of the present application, and the specific technical features may be combined with each other.

[0020] Figure 1 As shown, a digital twin-based ship safe navigation visualization method includes the following steps: S1. Collect marine meteorological data, ship host data and ship structure data to establish a ship database; The components of the ship safety navigation visualization system mainly include: meteorological sensors, wave sensors, stress and strain sensors, ship host sensors, photoelectric cameras, displays, data processing servers, software, etc. Meteorological sensors and wave sensors collect information such as wind direction, current, and waves in the marine environment. At the same time, they form ship data through ship host sensors, cameras, and stress and strain sensors, and transmit the data to the data processing server to form a ship and marine environment database. The ship's meteorological sensors and wave sensors are treated with anti-corrosion. The stress-strain sensors installed on the ship's main beam adopt a sealed design to effectively prevent corrosion from marine salt spray. The data processing server and display are installed indoors.

[0021] S2. Establish a simulated ocean environment model and use both data-driven and physical model-driven methods to simulate the ocean water environment.

[0022] S21. The kinematic model of the ship is constructed based on the modular concept and the time domain unified model theory as follows: The kinematic model of the ship is constructed based on the modular concept and the unified model theory in the time domain, and the formula is as follows: ; Where: is the total force on the hull, , , They represent the forces generated by the hull, propeller, and rudder respectively; , , , Represent the environmental disturbance forces caused by wind, current, first-order wave and second-order wave respectively; the hull force includes the hull radiation force and hydrostatic restoring force matrix calculated by the additional mass matrix A, damping coefficient matrix B and impulse response function matrix and nonlinear viscous forces calculated from the viscous hydrodynamic coefficients ; For time, is the time constant of the change, is the time constant, represents the skewness coefficient.

[0023] S22. A hydrodynamic coefficient database is constructed based on the three-dimensional digital model of the ship, potential flow and viscous fluid mechanics, ship model tests, and regression methods. The hydrodynamic coefficients of the ship under different motion states are calculated by interpolation using the database in the time domain simulation. Figure 2 The additional mass coefficients in the database are displayed, which are the frequency domain coefficients at wave encounter angles of 0°, 60°, 120° and 150°. The frequency domain coefficients will change with the wave encounter angle, and at the same wave encounter angle, the frequency domain coefficients will also change with the ship speed and wave frequency. In the actual navigation process, the wave encounter angle and the ship speed are changing continuously. Therefore, the hydrodynamic coefficients under different sea conditions can be smoothly calculated by interpolating in the hydrodynamic coefficient database.

[0024] The environmental forces on ships during navigation mainly come from wind, current and waves, which correspond to , , , The sea waves and wind force on ships during navigation can be calculated using the wind load coefficient: ; In the formula is the air density; is the apparent wind speed; , are the wind load coefficients in the x and y directions, is the wind load factor in any direction, is the wind load coefficient per unit area; is the lateral projection area of ​​the ship; The forward projection area from the ship; is the overall length of the vessel; wind disturbance forces of pitch and heave can be ignored.

[0025] Since the viscous nonlinear force of the ocean current on the hull has been calculated in the hull force, the ship is disturbed by the ocean current. It can be simplified into a translational motion with the ocean current, as follows: ; In the formula and represents the velocity component of the original current; is the velocity of the original ocean current; is the original flow direction; is the heading of the ship; and is the relative ship speed after vector uniform calculation, is the lateral current velocity, are the longitudinal current velocities, respectively.

[0026] Waves have a particularly significant impact on navigation. The effects of waves are mainly divided into the excitation effect of the first-order wave force and the drift effect of the second-order wave force. Among them, the calculation of the wave excitation force is based on the first-order wave load response factor and the wave spectrum, and it can be obtained: ; In the formula represents 6 degrees of freedom; is the first-order wave load coefficient corresponding to different degrees of freedom; is the ship speed, is the wave discrete frequency; is the wave encounter angle; For wave height and using wave spectrum , wave discrete frequency and wave diffusion angle calculate; is the random phase in the irregular wave; is the phase value of the wave load coefficient and is calculated from the real and imaginary parts of the wave load coefficient.

[0027] Second-order waves produce a slow drift effect on the ship's motion. The wave drift force is calculated using the second-order wave load coefficient and wave spectrum. Calculate according to the following formula: ; ; Where: is the average second-order wave load coefficient; is the average ship speed in the x-axis direction, is the average ship speed in the y-axis direction, is the average ship speed in any direction, is the discrete wave frequency Wave encounter angle The corresponding second-order load factor in the frequency domain; It is a meaningful wave high; is the density of seawater; is the acceleration due to gravity; It is the length between perpendicular lines of the ship.

[0028] S23. In order to maintain the consistency between the ocean environment in the digital twin and the real ocean environment, the ocean environment vector field is numerically solved to reproduce the real ocean information. NOAA's third-generation wave numerical model WAVEWATCHⅢ (WW3) is widely used in ocean simulation. The model has been extensively verified and has good simulation results. Therefore, this model is used in the digital twin to reproduce the real sea environment. The environmental vector field is: ; Where: N is the wave action density spectrum; is a two-dimensional Hamiltonian operator; is the group velocity; is the flow velocity; k and θ are the wave number and wave direction; s is a coordinate in the direction θ; m is a coordinate perpendicular to the direction s; is the source term of the spectrum, through the linear input term , Wind Input , nonlinear wave interaction term , dissipative term and seafloor friction Combination.

[0029] S24. Establish a real sea area database and a hydrodynamic database for real ocean environment reproduction and ship motion state prediction. The sensor data contains the real-time motion state and control equipment information of the real ship. This navigation state information can be directly transmitted to the navigation virtual reality system to drive the virtual ship. The wind, current and wave information obtained based on the real sea area database is used to generate a virtual ocean environment consistent with the real environment in the virtual reality system.

[0030] S3. Generate a three-dimensional model of the ship with ship data based on digital twin technology to simulate the navigation status; introduce the collected ocean meteorological data, ship main engine data and ship structure data into the three-dimensional model for status prediction, and use the data collected from the actual ship for comparative verification and visualization output.Figure 3 shown.

[0031] S31. Collect ship data network equipment data, intuitively display the ship data network equipment data based on the ship digital twin three-dimensional scene, and install stress and strain sensors on the ship body to collect ship body data.

[0032] S32. Based on the five-dimensional model architecture of digital twins and the “cloud” deployment mode of C2PS model, combined with the powerful data integration and system integration capabilities of the ship network information platform, a six-dimensional model of the ship three-dimensional visualization system based on digital twins is proposed, with the ship network information platform as the system service platform. as follows: ; PS are physical ship parameters; PS It is the basis for the six-dimensional model. By collecting physical ship equipment data, including: main engine data, generator data, navigation VDR data, communication and navigation data, ship meteorological data, navigation data, ship strain data, etc., a physical ship database is constructed.

[0033] VS VS is the virtual ship parameter; VS describes the PS geometric parameters (shape, size, position, etc.) through 3D modeling technology, making it have good temporal and spatial consistency with PS. The geometric modeling is further improved by using model rendering technology. At the same time, through the design of human-computer interaction interface and external input event response, the ship scene restoration simulation is realized.

[0034] SS Data simulation: collect physical ship parameters, simulate virtual ships, output physical ship and virtual ship data to the front end; and send simulation results to the historical database DD ; ; FS Mainly include: 1) Model services provided to VS, such as model building, model rendering, virtual scene construction, etc.; 2) Data management services provided to DD, such as data storage, data cleaning, data encapsulation, data mining, data fusion, data analysis, etc.; 3) Connection support provided to CN, such as interface services, protocol services, etc.; BS mainly refers to FD The series of services provided by the company mainly include: 1) providing various monitoring methods for ship management personnel, such as large monitoring screens, mobile devices (mobile phones, tablet computers, laptops, etc.); 2) providing real-time driving data for FD and providing feedback on human-computer interaction based on relevant decision-making rules.

[0035] DDFor historical database: provide data source for simulation; DD yes The basis of operation, DD Mainly includes PS data ( )、VS data( )、SS data( ) and knowledge data ( ).

[0036] ; It is mainly used to describe the attribute data of physical elements such as ship main engine equipment, hull stress and strain equipment, ship generators, etc. that constitute PS, as well as dynamic process data that can reflect the operating status of PS; Mainly includes data related to VS, such as being able to represent PS model related data (including geometric model, physical model, behavioral model, etc.); Mainly includes FS-related data (models, algorithms, database operations, etc.) and BS-related data (model dynamic process data, human-computer interaction data, etc.); Including ship expertise, industry standards, common algorithms, common data, common API interfaces, common model building methods, etc.

[0037] FD Front-end display: real-time dynamic display of the physical ship and virtual ship's heading; display of the ship's current status through video monitoring and 3D virtual models.

[0038] CN For data interaction.

[0039] Data interaction relationship CN The expression is as follows: ; Real-time data collection through data collection PS Data, and transfer the data to the VS corresponding model; Implemented via standard software interface PS and SS Two-way communication, data collection, transmission and storage; Real-time data collection using a variety of sensors, data acquisition devices, and standard / non-standard communication protocols PS Data and transmit to DD ; Implemented via standard software interface VS and SSTwo-way communication to achieve model-driven based on real-time data; Realized through network communication technology VS and FD Real-time synchronization and dynamic interaction; Store real-time data into DD In the meantime SS Through DD Statistical analysis of historical data and support for the use of common algorithms and mathematical models SS Operation; Through TCP / IP, UDP and other network communication technologies SS Supported by FD and DD Data interaction between them; It is realized through interface technology, network communication technology and front-end development technology FD and SS Data interaction between SS for FD Provide interface integration services, data interaction services, and define FD Human-computer interaction responds to decision rules.

[0040] S33. The three-dimensional model displayed by the navigation safety visualization software can be used for spatial information analysis. It can simultaneously display the ship's navigation route and the ocean water environment. It can intuitively and accurately display the ship's longitude and latitude, heading, attitude, speed, water temperature, water depth, wind speed, wind direction and other data information, as well as the different amplitudes of swaying of the hull itself in different sea conditions. It can also further simulate the ship's navigation attitude through the ocean environment model established in the previous step to assist in decision-making.

[0041] Virtual ships driven by sensor data can be used for real-time monitoring of the ship's motion status. The virtual ship can be considered a digital reproduction of the real ship. Through real-time sensor data updates, it maintains a consistent state with the real ship. Ship managers can achieve the purpose of real-time monitoring of the status of the real ship by observing the virtual ship. In addition, a virtual ship is generated based on the physical model. The ship receives information obtained from the sensor at the current moment, and predicts its status by combining the physical model with the marine environment vector field. The virtual ship can be considered as a digital representation of the ship's status for a period of time in the future. In the actual navigation process, the virtual ship predicted by the model can intuitively show the movement trend of the ship. The prediction information can also assist in the ship's collision avoidance decision-making, route planning and other tasks.

[0042] A digital twin-based ship safe navigation visualization system, including a data acquisition module, a data processing module and a data visualization module; The data acquisition module uses sensors to obtain relevant parameter data of the physical ship and builds a historical database; The data processing module: uses the historical database to simulate the virtual ship and outputs the physical ship and virtual ship data to the front end; Data visualization module: physical ship and virtual ship visualization output.

[0043] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A digital twin-based ship safe navigation visualization method, characterized in that: The following steps are involved: S1. Collect marine meteorological data, ship host data and ship structure data to establish a ship database; S2. Establish a simulated ocean environment model and use data-driven and physical model-driven methods to simulate the ocean water environment; S3. Generate a three-dimensional model of the ship with ship data based on digital twin technology to simulate the navigation status; introduce the collected ocean meteorological data, ship main engine data and ship structure data into the three-dimensional model for status prediction, and use the data collected from the actual ship for comparative verification and visualization output.

2. The method for visualizing safe navigation of a ship based on digital twin according to claim 1 is characterized in that: In step S1, meteorological sensors and wave sensors are used to collect wind direction, current, and wave information in the marine environment. At the same time, the ship's main body data is formed through the ship's main engine sensors, cameras, and stress-strain sensors, and the data is transmitted to the data processing server to form a ship's main body and marine environment database.

3. The method for visualizing safe navigation of a ship based on digital twin according to claim 1, characterized in that: To establish a simulated ocean environment model, the steps are as follows: S21. The kinematic model of the ship is constructed based on the modular concept and the time domain unified model theory, and the formula is as follows: ； Where: is the total force on the hull, , , They represent the forces generated by the hull, propeller, and rudder respectively; , , , Represent the environmental disturbance forces caused by wind, current, first-order wave and second-order wave respectively; the hull force includes the hull radiation force and hydrostatic restoring force matrix calculated by the additional mass matrix A, damping coefficient matrix B and impulse response function matrix and nonlinear viscous forces calculated from the viscous hydrodynamic coefficients ; For time, is the time constant of the change, is the time constant, represents the skewness coefficient; S22. Construct a hydrodynamic coefficient database based on the regression method, and use the database interpolation to calculate the hydrodynamic coefficients of the ship under different motion states in the time domain simulation; S23. Reproduce the real ocean information by numerically solving the ocean environment vector field. The formula is as follows: ； Where: N is the wave action density spectrum; is a two-dimensional Hamiltonian operator; is the group velocity; is the flow rate; and is the wave number and wave direction; s It is the direction A coordinate of is the coordinate perpendicular to the s direction; is the source term of the spectrum, through the linear input term , Wind Input , nonlinear wave interaction term , dissipative term and seafloor friction Combination S24. Establish a real sea area database and a hydrodynamic database for the purpose of reproducing the real ocean environment and predicting the ship motion status.

4. The method for visualizing safe navigation of a ship based on digital twin according to claim 3 is characterized in that: In step S22, the environmental effects on the ship during navigation mainly come from wind, current and waves, which correspond to , , , , where the sea waves and the wind force on the ship during navigation can be calculated using the wind load coefficient, the expression is as follows: ； In the formula is the air density; is the apparent wind speed; , are the wind load coefficients in the x and y directions, is the wind load factor in any direction, is the wind load coefficient per unit area; is the lateral projection area of ​​the ship; The forward projection area from the ship; is the total length of the ship; since the viscous nonlinear force of the current on the hull has been calculated in the hull force, the ship is disturbed by the current Simplified as a translational motion with the ocean current, as follows: ； In the formula and represents the velocity component of the original current; is the velocity of the original ocean current; is the original flow direction; is the heading of the ship; and is the relative ship speed after vector uniform calculation, is the lateral current velocity, are the longitudinal current velocities, respectively.

5. The method for visualizing safe navigation of a ship based on digital twin according to claim 4 is characterized in that: The calculation of wave excitation force is based on the first-order wave load response factor and wave spectrum, and it can be obtained: ； In the formula represents 6 degrees of freedom; is the first-order wave load coefficient corresponding to different degrees of freedom; is the ship speed, is the wave discrete frequency; is the wave encounter angle; For wave height and using wave spectrum , wave discrete frequency and wave diffusion angle calculate; is the random phase in the irregular wave; is the phase value of the wave load coefficient and is calculated from the real and imaginary parts of the wave load coefficient, is the wave discrete frequency increment, is the diffusion angle increment.

6. The method for visualizing safe navigation of a ship based on digital twin according to claim 4 is characterized in that: Second-order waves produce a slow drift effect on the ship's motion. The wave drift force is calculated using the second-order wave load coefficient and wave spectrum. Calculate according to the following formula: ； ； Where: is the average second-order wave load coefficient; is the average ship speed in the x-axis direction, is the average ship speed in the y-axis direction, is the average ship speed in any direction, is the discrete wave frequency and wave encounter angle The corresponding second-order load factor in the frequency domain; It is a meaningful wave high; is the density of seawater; is the acceleration due to gravity; It is the length between perpendicular lines of the ship.

7. The method for visualizing safe navigation of a ship based on digital twin according to claim 1, characterized in that: In step S3, a digital twin model is constructed : ； PS are physical ship parameters; VS are virtual ship parameters; SS For data simulation: collect physical ship parameters, simulate the virtual ship, and output the physical ship and virtual ship data to the front end; And send the simulation results to the historical database DD ; DD For historical database: provide data source for simulation; FD For front-end display: real-time dynamic display of physical and virtual ship headings; CN For data interaction.

8. The method for visualizing safe navigation of a ship based on digital twin according to claim 7 is characterized in that: Data interaction relationship CN The expression is as follows: ； Real-time data collection through data collection PS Data, and transfer the data to the VS corresponding model; Implemented via standard software interface PS and SS Two-way communication; Real-time data collection using a variety of sensors, data acquisition devices, and standard / non-standard communication protocols PS Data and transmit to DD ; Implemented via standard software interface VS and SS Two-way communication to achieve model-driven based on real-time data; Realized through network communication technology VS and FD Real-time synchronization and dynamic interaction; Store real-time data into DD In the meantime SS Through DD Statistical analysis of historical data and support for the use of common algorithms and mathematical models SS Operation; Through network communication technology SS Supported by FD and DD Data interaction between them; It is realized through interface technology, network communication technology and front-end development technology FD and SS Data interaction between SS for FD Provide interface integration services, data interaction services, and define FD Human-computer interaction responds to decision rules.

9. A digital twin-based ship safe navigation visualization system, using the digital twin-based ship safe navigation visualization method according to any one of claims 1 to 8, characterized in that: It includes data acquisition module, data processing module and data visualization module; The data acquisition module uses sensors to obtain relevant parameter data of the physical ship and builds a historical database; The data processing module: uses the historical database to simulate the virtual ship and outputs the physical ship and virtual ship data to the front end; Data visualization module: physical ship and virtual ship visualization output.

10. The digital twin-based ship safe navigation visualization system according to claim 9 is characterized in that: The data visualization module: synchronously displays the ship's navigation route and the ocean water environment, and can intuitively and accurately display the ship's latitude and longitude, heading, attitude, speed, water temperature, water depth, wind speed, wind direction and other data information, as well as the different amplitudes of swaying of the hull itself in different sea conditions, and further simulate the ship's navigation attitude through the established ocean environment model to assist decision-making.

Images