A polar ship navigation simulation system and modeling method

Abstract

The present invention discloses a polar ship navigation simulation system and modeling method, which relate to the field of ship and ocean engineering. The system solves the problem that the existing polar ship navigation mainly considers the influence of ice on the hull motion performance, but lacks consideration of the influence of crushed ice on propeller thrust. The present invention provides the following scheme, wherein the system includes subsystems such as a comprehensive management and evaluation subsystem, and constructs a six-degree-of-freedom motion model of the ship; a thrust calculation model is constructed for the problem of the influence of crushed ice during propeller propulsion, and the crushed ice motion is solved by treating the crushed ice as an independent moving object and obtaining the relative motion speed of the ship and the crushed ice. In the propeller modeling process, the influence of crushed ice on propeller performance is considered by taking into account the relative speed between the ship and the crushed ice, and the influence is applied to the model; the annular crack method is used to determine the crushed shape of flat ice, and the generated crushed ice is close to the real situation. It is also suitable for providing specific simulated navigation training for crew members sailing in polar regions.

Description

Technical Field

[0001] The invention belongs to the technical field of ships and marine engineering, and in particular relates to a polar ship navigation simulation system and a modeling method. Background Art

[0002] With the opening of the Arctic route, the safety of ships sailing in polar regions has become increasingly serious. The polar hazardous environment, navigation characteristics, ice loads and other aspects are closely related to the safety and efficiency of polar ship navigation. The polar ship navigation simulation system can be used to provide specific simulated navigation training for crew members sailing in ice areas, to prepare for polar navigation with a good theoretical basis and practical skills for driving, to further understand the special environment of polar waters, and to minimize navigation risks. The physical reality, behavioral reality and environmental reality of the polar ship navigation simulation system are important factors affecting the training effect.

[0003] Patent document CN116011294A discloses a method for building a six-degree-of-freedom ROV operation simulation platform, and proposes that the method for building a six-degree-of-freedom dynamic model of a mother ship cannot take into account the factors affecting ship navigation in the polar environment, and is not suitable for ship polar navigation motion calculation. Based on the problems existing in the prior art, a six-degree-of-freedom motion simulation model of a polar ship and a ship-flat ice / crushed ice collision simulation model are established to establish a simulation system, ensuring the physical reality, behavioral reality and environmental reality of the ship, ice and marine environment, which is of great significance to improving the performance of the simulation system and the training functionality.

[0004] The existing polar ship navigation simulation system has the following shortcomings:

[0005] 1. Insufficient impact of ice on hydrodynamics: Polar ship navigation mainly considers the impact of ice on the hull's motion performance, but lacks consideration of the impact of broken ice on propeller thrust.

[0006] 2. The contradiction between real-time and accuracy of ice load calculation: It is difficult to ensure real-time requirements when calculating ice load using discrete element or finite element methods. The empirical formula method has a fast calculation speed but cannot produce actual crushed ice.

[0007] 3. Single ice material parameters: The characteristics of polar ice materials are not single in the sea area, so data such as ice thickness, density, and strength need to be changed in real time. Summary of the invention

[0008] The present invention aims to solve the following technical problems in the prior art. First, the influence of ice on hydrodynamics is insufficient: polar ship navigation mainly considers the influence of ice on the hull's motion performance, and lacks consideration of the influence of crushed ice on propeller thrust. Secondly, there is a contradiction between the real-time and accuracy of ice load calculation: it is difficult to ensure the real-time requirements for ice load calculation using discrete element or finite element methods, and the empirical formula method has a fast calculation speed but cannot produce actual crushed ice. Finally, the ice material parameters are single: the characteristics of polar ice materials are not single in the sea area, so data such as ice thickness, density, and strength need to be changed in real time.

[0009] In order to overcome all the deficiencies in the prior art, the present invention proposes the following technical solutions:

[0010] Solution 1: A polar ship navigation simulation system, comprising a comprehensive management and evaluation subsystem, a ship driving control simulation subsystem, a polar environment simulation subsystem, a polar ship real-time motion simulation subsystem and a polar ship navigation vision simulation subsystem;

[0011] The comprehensive management and evaluation subsystem includes trainer software and electronic chart software. The trainer software is used to provide polar environment and ice distribution input conditions for the polar environment simulation subsystem; the electronic chart software is used to provide the polar ship motion simulation subsystem with the initial position of the ship and the route planning in real time, and control the simulation process of the simulation system at the same time;

[0012] The ship real-time motion simulation subsystem includes a propeller operation module, a steering gear operation module, and a driving and navigation control module; it is used to provide propeller speed, rudder angle and propeller fault control instructions for the polar ship real-time motion simulation subsystem, so as to simulate ship navigation control;

[0013] The polar environment simulation subsystem includes a wind speed module, a wave field module, a flow velocity module, and an ice field module; and establishes a ship-flat ice collision model and a ship-crushed ice collision model to calculate polar environment loads, ice loads, ice crushing and motion data;

[0014] The polar ship real-time motion simulation subsystem includes a propeller module, a rudder module, and a hull module. By establishing a six-degree-of-freedom motion simulation model of the ship, the ship motion considering the influence of wind, waves, currents, and ice loads is calculated;

[0015] The polar ship navigation visual simulation subsystem receives ice crushing and motion data calculated by the polar environment simulation subsystem and ship motion data calculated by the polar ship real-time motion simulation subsystem, and is used to display and update polar navigation, atmosphere, ocean, and ice field scenes in real time.

[0016] Further, a preferred embodiment is provided, wherein the polar ship navigation visual simulation subsystem includes a polar ship motion simulation drive module, a sea ice motion simulation drive module, a polar environment simulation module and a polar navigation auxiliary information display module;

[0017] The polar ship motion simulation driving module is used to receive and update the motion posture of the polar ship during navigation in real time;

[0018] The sea ice motion simulation driving module is used to receive and update the distribution of floating ice in the ship's navigation area in real time;

[0019] The polar environment simulation module is used to synchronously update the polar environment according to the instructor's instructions;

[0020] The polar navigation auxiliary information display module is used to dynamically display the ice thickness and interference distance in the visual scene.

[0021] Solution 2: A polar ship navigation simulation modeling method, the polar ship navigation simulation modeling method is implemented by the system described in any one of Solution 1, and the polar ship navigation simulation modeling method comprises the following steps:

[0022] Step 1: Set environmental conditions, sea ice conditions, initial position of the ship and expected navigation track through the trainer software and electronic chart software of the integrated management and evaluation subsystem, and issue simulation tasks;

[0023] Step 2: According to the simulation task released in step 1, the polar environment simulation subsystem calculates the wind, wave and current loads through the wind speed module, wave field module and current velocity module according to the set environmental conditions, and uses a multi-threaded parallel programming method to traverse the boundary points of the ship's waterline surface and the nearby flat ice and broken ice boundary points to detect the ship-ice contact situation;

[0024] Step 3: Based on the detection of ship-ice contact in step 2, when the ship-ice contact is detected, the ice field module calculates the crushing of smooth ice, the movement of broken ice, and the total load of smooth ice and broken ice according to the ship-smooth ice collision model and the ship-broken ice collision model according to the distribution of sea ice, ice thickness, and material properties;

[0025] Step 4: The polar ship real-time motion simulation subsystem uses the wind load, wave load, relative speed between the ship and the current, total load of smooth ice, and total load of crushed ice calculated by the polar environment simulation subsystem as environmental load inputs, and uses the rotation speed and rudder angle provided by the polar ship driving control simulation subsystem as control command inputs to respectively establish a propeller model, a rudder model, and a polar ship six-degree-of-freedom motion simulation model;

[0026] Step 5. The polar ship navigation visual simulation subsystem generates a three-dimensional scene according to the navigation sea area and wind, wave and current environmental conditions released by the trainer software, updates the distribution of flat ice and broken ice according to the flat ice crushing characteristic data and broken ice movement data calculated by the polar environment simulation subsystem, and updates the polar ship navigation simulation three-dimensional scene according to the ship navigation motion data calculated by the polar ship real-time motion simulation subsystem.

[0027] Furthermore, a preferred embodiment is provided, wherein step three also includes calculating the ship-ice contact area, the extrusion pressure and friction force between the ship and the ice, and the bending failure load of the flat ice, determining the crushing of the flat ice, and representing the shape characteristics of the crushed ice after the flat ice breaks by the radius of the crushed ice and the opening angle of the ice wedge.

[0028] Further, a preferred embodiment is provided, wherein in step 3, the ship-ice contact area, the extrusion force and friction force between the ship and the ice, and the bending failure load of the flat ice are calculated, the flat ice crushing situation is judged, and the shape characteristics of the broken ice after the flat ice is broken are expressed by the radius of the broken ice and the opening angle of the ice wedge, which specifically includes the following steps:

[0029] S31, first through the ice thickness h i , the angle between the normal direction outside the hull and the downward vertical axis at the point where the ship contacts the ice And extrusion depth L d , determine the shape of the ship-ice contact point, and calculate the contact area A between the ship and the flat ice c , the ship-flat ice collision model is:

[0030]

[0031] Among them, L h L is the length of the ship edge in contact with the ice edge on the horizontal ice surface; d is the depth to which the ship is squeezed into the ice boundary on a horizontal ice surface; h is the angle between the normal direction outside the hull and the downward vertical axis at the point where the ship contacts the ice; i is the thickness of the ice layer;

[0032] S32, secondly, the contact area A between the ship and the flat ice c Calculate the squeeze force F between the ship and ice c and friction F f , the ship-flat ice collision model is:

[0033] F c =n c ·σ c A c

[0034] F fz =-τ c ·μ fF c v z / V

[0035] F fl =-τ c ·μ f F c v l / V

[0036] Among them, n c is the unit normal of the ship-ice contact surface; σ c is the compressive strength of ice; τ c is the unit tangent of the ship-ice contact surface; μ f F is the ship-ice friction coefficient; fz is the upward friction along the ship-ice contact surface; v z F is the relative speed of the ship-ice upward along the ship-ice contact surface; fl is the friction force in the horizontal direction along the ship-ice contact surface; v l is the relative speed of the ship to the ice in the horizontal direction of the ship-ice contact surface; V is the total speed of the ship sliding relative to the ice;

[0037] S33, the total load of the flat ice on the mother ship in the coordinate system is τ pice :

[0038]

[0039] in, is the transformation matrix between the local coordinates of the ship-ice contact surface and the hull coordinates;

[0040] S34. In order to determine the fracture condition and shape characteristics of the flat ice that collides with the hull, calculate the flat ice bending failure load P f , the calculation model of ship-ice collision is:

[0041]

[0042] Among them, C f is an empirical parameter; σ f is the ice bending strength; θ is the opening angle of the ice wedge at the ship-ice contact point, h i is the thickness of the ice layer;

[0043] When the combined force of the ship's ice extrusion force and the friction force in the vertical direction Greater than the bending failure limit load P f When the flat ice breaks, the broken ice falls off;

[0044] S35. The shape of the broken ice is fan-shaped. The annular crack method is used to express the shape characteristics of the broken ice using the crushing radius and the opening angle of the ice wedge at the ship-ice contact point. The calculation model of the crushing radius R is:

[0045]

[0046] Among them, C l , C v is the empirical coefficient, ν is Poisson's ratio, E is the elastic modulus of ice; ρ w is the density of seawater; v n is the relative normal velocity between the discrete point of the waterline and the discrete point of the flat ice boundary;

[0047] S36. After determining the characteristic crushing radius of the detached ice shape and the opening angle of the ice wedge at the ship-ice contact point, break off the detached ice according to the sea ice distribution published by the instructor software, update the smooth ice boundary, indicate the smooth distribution, and generate a boundary for the ice detached from the smooth ice.

[0048] Further, a preferred embodiment is provided, in step 3, when the contact between the ship and the ice is detected, the ice field module calculates the crushing of the smooth ice, the movement of the broken ice, and the total load of the smooth ice and the broken ice according to the ship-smooth ice collision model and the ship-crushed ice collision model according to the distribution of sea ice, the thickness of the ice layer, and the material properties.

[0049] S311. First, a dynamic model of each piece of ice in the ship's navigation area is established:

[0050]

[0051] Among them, F s T is the combined external force generated by the wind, wave and current forces acting on the broken ice and the contact forces with the flat ice, broken ice and the hull. s is the total external torque; m s is the total mass of crushed ice currently calculated; J s is the total inertia tensor;

[0052] Enter F s 、T s 、m s and J s The value of the crushed ice motion velocity vector v s ; Angular velocity vector ω s , the integral obtains the displacement and rotational motion data of each piece of crushed ice, indicating the distribution of crushed ice;

[0053] S322. The contact between the solid surfaces of crushed ice is calculated using a linear spring damping system. The contact force calculation models of ship-crushed ice, crushed ice-crushed ice, and crushed ice-smooth ice near the hull are:

[0054] F n =-kd n -ηv n

[0055]

[0056] Where k is the elastic coefficient of ice material; η is the damping coefficient of ice material; d n is the normal overlap distance between ice and other objects, v n is the normal overlap velocity, d t is the tangential overlap distance, v t is the tangential overlap velocity, μ is the friction coefficient; n t is the unit direction tangent to the ice-crushing boundary; F n is the normal contact force inward from the ice boundary and F t is the tangential contact force along the ice boundary;

[0057] S333, the total load of the mother ship on the broken ice in the coordinate system is τ sice :

[0058]

[0059] is the transformation matrix between the local coordinates of the ship-ice contact surface and the hull coordinates.

[0060] Further, a preferred embodiment is provided, in which the propeller thrust affected by ice is calculated by taking the rotation speed and rudder angle provided by the polar ship driving control simulation subsystem as control instructions in step 4; that is, the propeller thrust affected by crushed ice T P The calculation method is:

[0061]

[0062] Where: t p is the thrust reduction of the propeller; ρ w is the density of seawater; n p is the propeller speed; D p is the propeller diameter; K T is the thrust coefficient; W p is the wake velocity; u is the relative speed between the ship and the broken ice; T P is the propeller thrust.

[0063] Further, a preferred implementation is provided, in which the method for establishing a six-degree-of-freedom motion simulation model of a ship in step 4 is:

[0064]

[0065] Where: M0 is the sum of the mother ship mass and the additional mass; C RB0 is the centripetal force of the rigid body and the fluid, C A0 is the Coriolis force matrix; v r0is the relative speed of the mother ship and the ocean current in the body coordinate system; D0 is the damping matrix; K0(t-γ) is the time delay function, where t is the simulation time and γ is the integral variable; U is the longitudinal speed of the mother ship; e1 is the longitudinal unit vector; G0 is the stiffness matrix of the mother ship; τ wind0 is the wind load; τ wave0 is the wave load; τ P is the propeller thrust; τ R is the ship's rudder force; τ ice is the total ice load, including the leveling ice load τ pice and crushed ice load τ sice ;

[0066] Solve to obtain the acceleration of polar ship navigation and velocity v0, and the ship's motion posture is obtained through the fourth-order Runge-Kutta integration.

[0067] Furthermore, a preferred implementation manner is provided, in which the method by which the polar ship navigation vision simulation subsystem generates a three-dimensional scene according to the navigation area and wind, wave and current environmental conditions published by the trainer software in step five is as follows: the polar ship navigation vision simulation subsystem performs three-dimensional scene simulation based on a three-dimensional engine, and the simulation process uses the navigation area and wind, wave and current environmental conditions published by the trainer software to load the initial position of the ship, the initial distribution of flat ice and crushed ice, and drives the three-dimensional engine to render the three-dimensional models of the ocean environment, atmospheric environment, ice area and ship to generate a three-dimensional scene.

[0068] The present invention is beneficial in that:

[0069] The present invention constructs a six-degree-of-freedom motion model of a ship in view of the ice load problem when the ship sails in ice areas. Compared with the prior art, the six-degree-of-freedom motion model of the ship constructed by the present invention is suitable for use in polar environments.

[0070] The present invention constructs a thrust calculation model to address the problem of the influence of crushed ice on propeller propulsion. The crushed ice motion is solved by treating the crushed ice as an independent moving object and the relative motion speed of the ship and the crushed ice is obtained. In the propeller modeling process, the influence of the crushed ice on the propeller performance is considered by taking into account the relative speed between the ship and the crushed ice, and the effect is applied to the ship's six-degree-of-freedom motion response model.

[0071] The ice load calculation of the present invention includes the loads of flat ice and crushed ice, and adopts the annular crack method to determine the crushed shape of flat ice. The calculation speed is fast and the simulation result is more accurate, and the generated crushed ice is close to the actual situation.

[0072] The ship-smooth ice contact point detection part of the present invention adopts a multi-process parallel method to traverse the intersection test of the ship waterline boundary point line segment and the smooth ice boundary point line segment, thereby improving the calculation efficiency of the simulation system.

[0073] The present invention displays and updates the ice cracks and broken ice after the icebreaker acts on the ice layer in real time. The crack shape, size, broken ice shape, movement and distribution are all calculated by the ship-leveling / broken ice collision simulation model, which conforms to the ice dynamics law after the ship acts on ice and has a high sense of behavior and environmental reality.

[0074] That is, the present invention is also applicable to the field of providing specific simulated navigation training for crew members sailing in polar regions. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 This is a schematic diagram of the composition of a polar ship navigation simulation system described in Implementation Method 1.

[0076] Figure 2 This is a flow chart of a polar ship navigation simulation modeling method described in Implementation Method 3. DETAILED DESCRIPTION

[0077] In order to make the purpose, technical solutions and advantages of the implementation methods of the present application clearer, the technical solutions in the implementation methods of the present application will be clearly and completely described below in conjunction with the drawings in the implementation methods of the present application. Obviously, the described implementation methods are only part of the implementation methods of the present application, not all of the implementation methods.

[0078] Embodiment 1. This embodiment provides a polar ship navigation simulation system, which includes a comprehensive management and evaluation subsystem, a ship driving control simulation subsystem, a polar environment simulation subsystem, a polar ship real-time motion simulation subsystem and a polar ship real-time motion simulation subsystem;

[0079] The comprehensive management and evaluation subsystem includes trainer software and electronic chart software. The trainer software is used to provide polar environment and ice distribution input conditions for the polar environment simulation subsystem; the electronic chart software is used to provide the polar ship motion simulation subsystem with the initial position of the ship and the route planning in real time, and control the simulation process of the simulation system at the same time;

[0080] The ship real-time motion simulation subsystem includes a propeller operation module, a steering gear operation module, and a driving and navigation control module; it is used to provide propeller speed, rudder angle and propeller fault control instructions for the polar ship real-time motion simulation subsystem, so as to simulate ship navigation control;

[0081] The polar environment simulation subsystem includes a wind speed module, a wave field module, a flow velocity module, and an ice field module; and establishes a ship-flat ice collision model and a ship-crushed ice collision model to calculate polar environment loads, ice loads, ice crushing and motion data;

[0082] The polar ship real-time motion simulation subsystem includes a propeller module, a rudder module, and a hull module. By establishing a six-degree-of-freedom motion simulation model of the ship, the ship motion considering the influence of wind, waves, currents, and ice loads is calculated;

[0083] The polar ship navigation visual simulation subsystem receives ice crushing and motion data calculated by the polar environment simulation subsystem and ship motion data calculated by the polar ship real-time motion simulation subsystem, and is used to display and update polar navigation, atmosphere, ocean, and ice field scenes in real time.

[0084] See also Figure 1 To illustrate this embodiment, a polar ship navigation simulation system includes: a comprehensive management and evaluation subsystem, a polar ship driving control simulation subsystem, a polar environment simulation subsystem, a polar ship real-time motion simulation subsystem, and a polar ship navigation vision simulation subsystem. Each system is based on a TCP / UDP network and uses publish / subscribe, client / server and other models to achieve data transmission of multiple communication mechanisms.

[0085] The comprehensive management and evaluation subsystem and polar ship driving control simulation subsystem provide the navigation sea reference altitude, wind speed, frequency, significant wave height, period, water depth, tidal flow velocity, flow direction environmental conditions, sea ice distribution, ice thickness, material properties and other sea ice conditions, the ship's initial position and expected navigation trajectory and other simulation working condition settings, as well as the propeller speed, rudder angle and thruster fault control command input functions;

[0086] The polar environment simulation subsystem and polar ship real-time motion simulation subsystem provide wind, wave, current, ice load, flat ice crushing, ice breaking motion, propeller thrust and rudder force considering the influence of ice breaking, and polar ship navigation motion calculation functions considering the influence of wind, wave, current and ice load;

[0087] Implementation method 2: This implementation method further limits the polar ship navigation simulation system described in implementation method 1. The polar ship navigation visual simulation subsystem includes a polar ship motion simulation drive module, a sea ice motion simulation drive module, a polar environment simulation module and a polar navigation auxiliary information display module.

[0088] The polar ship motion simulation driving module is used to receive and update the motion posture of the polar ship during navigation in real time;

[0089] The sea ice motion simulation driving module is used to receive and update the distribution of floating ice in the ship's navigation area in real time;

[0090] The polar environment simulation module is used to synchronously update the polar environment according to the instructor's instructions;

[0091] The polar navigation auxiliary information display module is used to dynamically display the ice thickness and interference distance in the visual scene.

[0092] The polar ship navigation visual simulation subsystem described in this embodiment updates the polar ship navigation simulation scene in real time according to the ship position and posture calculated by the polar ship real-time motion simulation subsystem, assists the driver to judge the navigation status of the ship in the ice area, and divides the polar three-dimensional scene into two sea ice driving modes: icebreaking navigation in the flat ice area and navigation in the crushed ice area. When simulating icebreaking navigation in the flat ice area, the distribution of flat ice and crushed ice in the navigation area is updated according to the ice surface cracks and crushed ice movement calculated by the ship-ice collision simulation model. When simulating navigation in the crushed ice area, the geometric shape of floating ice in the channel is randomly generated, the position of floating ice is updated according to the crushed ice movement data, and the lighting, ice and snow and wave effects are simulated according to the navigation sea area environmental conditions released by the comprehensive management and evaluation subsystem.

[0093] Implementation method 3: This implementation method proposes a polar ship navigation simulation modeling method, which is implemented by the system described in any one of implementation methods 1 to 2, and the polar ship navigation simulation modeling method includes the following steps:

[0094] Step 1: Set environmental conditions, sea ice conditions, initial position of the ship and expected navigation track through the trainer software and electronic chart software of the integrated management and evaluation subsystem, and issue simulation tasks;

[0095] Step 2: According to the simulation task released in step 1, the polar environment simulation subsystem calculates the wind, wave and current loads through the wind speed module, wave field module and current velocity module according to the set environmental conditions, and uses a multi-threaded parallel programming method to traverse the boundary points of the ship's waterline surface and the nearby flat ice and broken ice boundary points to detect the ship-ice contact situation;

[0096] Step 3: Based on the detection of ship-ice contact in step 2, when the ship-ice contact is detected, the ice field module calculates the crushing of smooth ice, the movement of broken ice, and the total load of smooth ice and broken ice according to the ship-smooth ice collision model and the ship-broken ice collision model according to the distribution of sea ice, ice thickness, and material properties;

[0097] Step 4: The polar ship real-time motion simulation subsystem uses the wind load, wave load, relative speed between the ship and the current, total load of smooth ice, and total load of crushed ice calculated by the polar environment simulation subsystem as environmental load inputs, and uses the rotation speed and rudder angle provided by the polar ship driving control simulation subsystem as control command inputs to respectively establish a propeller model, a rudder model, and a polar ship six-degree-of-freedom motion simulation model;

[0098] Step 5. The polar ship navigation visual simulation subsystem generates a three-dimensional scene according to the navigation sea area and wind, wave and current environmental conditions released by the trainer software, updates the distribution of flat ice and broken ice according to the flat ice crushing characteristic data and broken ice movement data calculated by the polar environment simulation subsystem, and updates the polar ship navigation simulation three-dimensional scene according to the ship navigation motion data calculated by the polar ship real-time motion simulation subsystem.

[0099] Implementation method 4. This implementation method is a further limitation of the polar ship navigation simulation modeling method described in implementation method 3. Step 3 also includes calculating the ship-ice contact area, the extrusion pressure and friction force between the ship and the ice, and the bending failure load of the flat ice, judging the crushing of the flat ice, and representing the shape characteristics of the crushed ice after the flat ice breaks through the radius of the crushed ice and the opening angle of the ice wedge.

[0100] Implementation mode 5: This implementation mode is a further limitation of the polar ship navigation simulation modeling method described in Implementation mode 4. In step 3, the ship-ice contact area, the extrusion force and friction force between the ship and the ice, and the bending failure load of the flat ice are calculated, the flat ice crushing situation is judged, and the shape characteristics of the broken ice after the flat ice is broken are expressed by the radius of the broken ice and the opening angle of the ice wedge. Specifically, the following steps are included:

[0101] S31, first through the ice thickness h i , the angle between the normal direction outside the hull and the downward vertical axis at the point where the ship contacts the ice And extrusion depth L d , determine the shape of the ship-ice contact point, and calculate the contact area A between the ship and the flat ice c , the ship-flat ice collision model is:

[0102]

[0103] Among them, L h L is the length of the ship edge in contact with the ice edge on the horizontal ice surface; d is the depth to which the ship is squeezed into the ice boundary on a horizontal ice surface; h is the angle between the normal direction outside the hull and the downward vertical axis at the point where the ship contacts the ice; i is the thickness of the ice layer;

[0104] S32, secondly, the contact area A between the ship and the flat ice c Calculate the squeeze force F between the ship and ice c and friction F f , the ship-flat ice collision model is:

[0105] F c =n c ·σ c A c

[0106] F fz =-τ c ·μ f F c v z / V

[0107] F fl =-τ c ·μ f F c v l / V

[0108] Among them, n c is the unit normal of the ship-ice contact surface; σ c is the compressive strength of ice; τ c is the unit tangent of the ship-ice contact surface; μ f F is the ship-ice friction coefficient; fz is the upward friction along the ship-ice contact surface; v z F is the relative speed of the ship-ice upward along the ship-ice contact surface; fl is the friction force in the horizontal direction along the ship-ice contact surface; v l is the relative speed of the ship to the ice in the horizontal direction of the ship-ice contact surface; V is the total speed of the ship sliding relative to the ice;

[0109] S33, the total load of the flat ice on the mother ship in the coordinate system is τ pice :

[0110]

[0111] in, is the transformation matrix between the local coordinates of the ship-ice contact surface and the hull coordinates;

[0112] S34. In order to determine the fracture condition and shape characteristics of the flat ice that collides with the hull, calculate the flat ice bending failure load P f , the calculation model of ship-ice collision is:

[0113]

[0114] Among them, C f is an empirical parameter; σ f is the ice bending strength; θ is the opening angle of the ice wedge at the ship-ice contact point, h i is the thickness of the ice layer;

[0115] When the combined force of the ship's ice extrusion force and the friction force in the vertical direction Greater than the bending failure limit load P f When the flat ice breaks, the broken ice falls off;

[0116] S35. The shape of the broken ice is fan-shaped. The annular crack method is used to express the shape characteristics of the broken ice using the crushing radius and the opening angle of the ice wedge at the ship-ice contact point. The calculation model of the crushing radius R is:

[0117]

[0118] Among them, C l , C v is the empirical coefficient, ν is Poisson's ratio, E is the elastic modulus of ice; ρ w is the density of seawater; v n is the relative normal velocity between the discrete point of the waterline and the discrete point of the flat ice boundary;

[0119] S36. After determining the characteristic crushing radius of the detached ice shape and the opening angle of the ice wedge at the ship-ice contact point, break off the detached ice according to the sea ice distribution published by the instructor software, update the smooth ice boundary, indicate the smooth distribution, and generate a boundary for the ice detached from the smooth ice.

[0120] Implementation method 6: This implementation method is a further limitation of the polar ship navigation simulation modeling method described in implementation method 3. In step 3, when the ship-ice contact is detected, the ice field module calculates the crushing of flat ice, the movement of broken ice, and the total load of flat ice and broken ice according to the ship-flat ice collision model and the ship-broken ice collision model according to the distribution of sea ice, ice thickness, and material properties. The method is:

[0121] S311. First, a dynamic model of each piece of ice in the ship's navigation area is established:

[0122]

[0123] Among them, F s T is the combined external force generated by the wind, wave and current forces acting on the broken ice and the contact forces with the flat ice, broken ice and the hull. s is the total external torque; m s is the total mass of crushed ice currently calculated; J s is the total inertia tensor;

[0124] Enter F s 、T s 、m s and J s The value of the crushed ice motion velocity vector v s ; Angular velocity vector ω s , the integral obtains the displacement and rotational motion data of each piece of crushed ice, indicating the distribution of crushed ice;

[0125] S322. The contact between the solid surfaces of crushed ice is calculated using a linear spring damping system. The contact force calculation models of ship-crushed ice, crushed ice-crushed ice, and crushed ice-smooth ice near the hull are:

[0126] F n =-kd n -ηv n

[0127]

[0128] Where k is the elastic coefficient of ice material; η is the damping coefficient of ice material; d n is the normal overlap distance between ice and other objects, v n is the normal overlap velocity, d t is the tangential overlap distance, v t is the tangential overlap velocity, μ is the friction coefficient; n t is the unit direction tangent to the ice-crushing boundary; F n is the normal contact force inward from the ice boundary and F t is the tangential contact force along the ice boundary;

[0129] S333, the total load of the mother ship on the broken ice in the coordinate system is τ sice :

[0130]

[0131] is the transformation matrix between the local coordinates of the ship-ice contact surface and the hull coordinates.

[0132] Embodiment 7. This embodiment further limits the polar ship navigation simulation modeling method described in Embodiment 3. In step 4, the propeller thrust affected by ice is calculated by using the rotation speed and rudder angle provided by the polar ship driving control simulation subsystem as control instructions; that is, the propeller thrust affected by crushed ice T P The calculation method is:

[0133]

[0134] Where: t p is the thrust reduction of the propeller; ρ w is the density of seawater; n p is the propeller speed; D p is the propeller diameter; K T is the thrust coefficient; W p is the wake velocity; u is the relative speed between the ship and the broken ice; T P is the propeller thrust.

[0135] Embodiment 8: This embodiment further limits the polar ship navigation simulation modeling method described in embodiment 3. The method for establishing the ship six-degree-of-freedom motion simulation model in step 4 is:

[0136]

[0137] Where: M0 is the sum of the mother ship mass and the additional mass; C RB0 is the centripetal force of the rigid body and the fluid, C A0 is the Coriolis force matrix; v r0 is the relative speed of the mother ship and the ocean current in the body coordinate system; D0 is the damping matrix; K0(t-γ) is the time delay function, where t is the simulation time and γ is the integral variable; U is the longitudinal speed of the mother ship; e1 is the longitudinal unit vector; G0 is the stiffness matrix of the mother ship; τ wind0 is the wind load; τ wave0 is the wave load; τ P is the propeller thrust; τ R is the ship's rudder force; τ ice is the total ice load, including the leveling ice load τ pice and crushed ice load τ sice ;

[0138] Solve to obtain the acceleration of polar ship navigation and velocity v0, and the ship's motion posture is obtained through the fourth-order Runge-Kutta integration.

[0139] Implementation method nine, this implementation method is a further limitation of the polar ship navigation simulation modeling method described in implementation method three. In step five, the method for the polar ship navigation visual simulation subsystem to generate a three-dimensional scene according to the navigation sea area and wind, wave and current environmental conditions published by the trainer software is as follows: the polar ship navigation visual simulation subsystem performs three-dimensional scene simulation based on a three-dimensional engine. During the simulation process, the initial position of the ship, the initial distribution of flat ice and crushed ice are loaded through the navigation sea area and wind, wave and current environmental conditions published by the trainer software, and the three-dimensional engine is driven to render the three-dimensional models of the ocean environment, atmospheric environment, ice area and ship to generate a three-dimensional scene.

[0140] Implementation Method 10: See Figure 2 To illustrate this embodiment, this embodiment provides the following examples, which are used to explain the above-mentioned embodiments 3 to 9, and the specific implementation process is as follows:

[0141] In order to verify the effectiveness and effect of the method described in this embodiment, taking the initial navigation simulation sea area of ​​a ship containing only flat ice as an example, an example of a polar ship navigation simulation system and modeling method includes the following steps:

[0142] Step 1: Start the comprehensive management and evaluation subsystem, set the reference altitude, wind speed, frequency, significant wave height, period, water depth, tidal velocity, flow direction and other environmental conditions of the navigation area through the coach software, and set the sea ice conditions such as flat ice distribution, ice thickness, ice elastic modulus, seawater density, etc. through the electronic chart software, set the initial position of the ship and the expected navigation track, and issue the simulation task;

[0143] Step 2: The polar environment simulation subsystem performs the following steps according to the current environmental conditions and sea ice conditions:

[0144] S21, the wind speed module generates a wind spectrum based on the navigation sea area reference altitude, the one-hour average wind speed at the reference altitude, and the frequency published by the trainer software, calculates the wind speed distribution time history, and calculates the wind load using the wind load coefficient according to the altitude above the water surface;

[0145] S22, the wave field module generates wave spectrum and directional spectrum according to the significant wave height, characteristic period, and directional spread function published by the coach software, calculates the wave height time history, and calculates the wave load using the response amplitude operator;

[0146] S23, the velocity module calculates the wind-induced velocity component according to the wind speed and sea conditions, calculates the velocity distribution history according to the water depth and tidal velocity published by the coach software, and obtains the relative speed between the ship and the current;

[0147] S24, discretizing the hull waterplane into boundary points, and traversing the ship waterplane boundary points and nearby flat ice boundary points by using a multi-threaded parallel programming method. If there is an ice boundary point inside the ship waterplane boundary, it means that the ship is in contact with ice;

[0148] Step 3: When a ship-ice collision is detected, the ice field module of the polar environment simulation subsystem calculates the flat ice crushing, the movement of the detached ice, and the total load of the flat ice and the detached ice according to the ship-flat ice collision, based on the sea ice distribution, ice thickness, ice elastic modulus, seawater density and other sea ice conditions released by the coach software:

[0149] The ship-flat ice collision simulation model is established through the ice field module. The ship-ice contact area, the extrusion force and friction force between the ship and the ice, and the flat ice bending failure load are calculated in steps to determine the flat ice breakage. The shape characteristics of the broken ice after the flat ice breaks are expressed by the radius of the broken ice and the opening angle of the ice wedge. The specific steps include the following:

[0150] S31, first through the ice thickness h i , the angle between the normal direction outside the hull and the downward vertical axis at the point where the ship contacts the ice And extrusion depth L d , determine the shape of the ship-ice contact point, and calculate the contact area A between the ship and the flat ice c , the calculation model is:

[0151]

[0152] The model input conditions include: L h L is the length of the ship edge in contact with the ice edge on the horizontal ice surface; d is the depth to which the ship is squeezed into the ice boundary on a horizontal ice surface; h is the angle between the normal direction outside the hull and the downward vertical axis at the point where the ship contacts the ice; i is the thickness of the ice layer;

[0153] S32, then through the contact area A c Calculate the squeeze force F between the ship and ice c and friction F f , the calculation model is:

[0154] F c =n c ·σ c A c

[0155] F fz =-τ c ·μ f F c v z / V

[0156] F fl =-τ c ·μ f F c v l / V

[0157] Input conditions include: c is the unit normal of the ship-ice contact surface; σ c is the compressive strength of ice; τ c is the unit tangent of the ship-ice contact surface; μ f F is the ship-ice friction coefficient; fz is the upward friction along the ship-ice contact surface; v z F is the relative speed of the ship-ice upward along the ship-ice contact surface; fl is the friction force in the horizontal direction along the ship-ice contact surface; v l is the relative speed of the ship to the ice in the horizontal direction of the ship-ice contact surface; V is the total speed of the ship sliding relative to the ice;

[0158] S33, the total load of the flat ice on the mother ship in the coordinate system is τ pice :

[0159]

[0160] Input conditions include: F c is the extrusion pressure; F fz and F fl is the friction force; is the transformation matrix between the local coordinates of the ship-ice contact surface and the hull coordinates;

[0161] S34. In order to determine the fracture condition and shape characteristics of the flat ice that collides with the hull, calculate the flat ice bending failure load Pf , the calculation model is:

[0162]

[0163] Input conditions include: C f is an empirical parameter; σ f is the ice bending strength; θ is the opening angle of the ice wedge at the ship-ice contact point, h i is the thickness of the ice layer;

[0164] When the combined force of the ship's ice extrusion force and the friction force in the vertical direction Greater than the bending failure limit load P f When the flat ice breaks, the broken ice falls off;

[0165] S35. The shape of the broken ice is fan-shaped. The annular crack method is used to express the shape characteristics of the broken ice using the crushing radius and the opening angle of the ice wedge at the ship-ice contact point. The calculation model of the crushing radius R is:

[0166]

[0167] The model input conditions include: C l , C v is the empirical coefficient, ν is Poisson's ratio, E is the elastic modulus of ice; ρ w is the density of seawater; v n is the relative normal velocity between the discrete point of the waterline and the discrete point of the flat ice boundary;

[0168] S36. After determining the shape characteristics of the detached ice (the crushing radius and the opening angle of the ice wedge at the ship-ice contact point), break off the detached ice according to the sea ice distribution released by the instructor software, update the flat ice boundary, indicate the flat distribution, and generate a boundary for the ice detached from the flat ice; in the process of calculating the opening angle of the ice wedge at the ship-ice contact point, first traverse the contact points at both ends of the flat ice boundary between the waterline of the current position of the ship and the obtained waterline; if the distance between the contact point and the i-th flat ice boundary point after discretization is less than the crushing radius, and the distance between the contact point and the continuous i+1-th flat ice boundary point is greater than the crushing radius, then the breaking point is located between these continuous flat ice boundary points, and the distance between the breaking point and the contact point is equal to the crushing radius, and the breaking points at both ends of the flat ice annular crack can be determined by linear interpolation; then the vertex of the ice wedge at the ship-ice contact point is determined by the intersection of the perpendicular bisectors of the two end breaking points and the layer ice boundary, and the angle between the vertex of the ice wedge and the two end breaking points solved by the inverse trigonometric function is the opening angle of the ice wedge.

[0169] After the flat ice breaks and produces broken ice, the broken ice moves as an independent object. When the ship collides with the broken ice, the ship-broken ice collision simulation model is established through the ice field module. The solid surface contact forces between ship-broken ice, broken ice-broken ice, and broken ice-flat ice are calculated in steps. The movement of each independent piece of broken ice in the ship's navigation area under the influence of wind, waves, currents and collisions is calculated. The specific steps include:

[0170] S311. First, a dynamic model of each piece of broken ice in the ship's navigation area is established:

[0171]

[0172] The model input conditions include: F s T is the combined external force generated by the wind, wave and current forces acting on the broken ice and the contact forces with the flat ice, broken ice and the hull. s is the total external torque; m s is the total mass of crushed ice currently calculated; J s is the total inertia tensor;

[0173] Enter F s 、T s 、m s and J s The value of the crushed ice motion velocity vector v s ; Angular velocity vector ω s , the integral obtains the displacement and rotational motion data of each piece of crushed ice, indicating the distribution of crushed ice;

[0174] S322. The contact between the solid surfaces of crushed ice is calculated using a linear spring damping system. The contact force calculation models of ship-crushed ice, crushed ice-crushed ice, and crushed ice-smooth ice near the hull are:

[0175] F n =-kd n -ηv n

[0176]

[0177] The model input conditions include: k is the elastic coefficient of ice material; η is the damping coefficient of ice material; d n is the normal overlap distance between ice and other objects, v n is the normal overlap velocity, d t is the tangential overlap distance, v t is the tangential overlap velocity, μ is the friction coefficient; n t is the unit direction tangent to the ice-crushing boundary; F n is the normal contact force inward from the ice boundary and F t is the tangential contact force along the ice boundary;

[0178] S333, the total load of the mother ship on the broken ice in the coordinate system is τ sice :

[0179]

[0180] is the transformation matrix between the local coordinates of the ship-ice contact surface and the hull coordinates.

[0181] Step 4: The polar ship driving control simulation subsystem configures the ship propeller fault conditions through the driving and navigation control module according to the navigation tasks issued by the trainer software, and provides speed and rudder angle control instructions to the propeller module and rudder module of the polar ship real-time motion simulation subsystem by operating the propeller simulation control handle and the steering gear simulation control handle, so that the ship can sail in different directions;

[0182] Step 5: The polar ship real-time motion simulation subsystem uses the wind load, wave load, relative speed between the ship and the current calculated by the polar environment simulation subsystem in S21 to S23, the total load of flat ice calculated by S313, and the total load of crushed ice calculated by S333 as environmental load inputs. The speed and rudder angle provided by the polar ship driving control simulation subsystem in step 4 are used as control command inputs. The propeller model, rudder model and polar ship six-degree-of-freedom motion simulation model are established in steps to calculate the polar ship navigation motion data considering the influence of wind, wave, current and ice loads. Specifically, the following steps are included:

[0183] S51, the propeller module establishes a ship propeller model, takes into account the relative speed between the ship and the crushed ice, considers the influence of crushed ice on the propeller performance, and calculates the propeller thrust considering the influence of ice according to the propeller speed command provided by the polar ship driving control simulation subsystem; propeller thrust calculation model affected by crushed ice:

[0184]

[0185] The model input conditions include: p is the thrust reduction of the propeller; ρ w is the density of seawater; n p is the propeller speed; D p is the propeller diameter; K T is the thrust coefficient; W p is the wake velocity; u is the relative speed between the ship and the broken ice; T P is the propeller thrust.

[0186] S52, the rudder module calculates the ship's rudder force according to the rudder angle control command provided by the polar ship driving control simulation subsystem by establishing a rudder model, taking into account the flow velocity at the rudder, considering the influence of the ocean current on the rudder effect, and controlling the ship's navigation direction; Rudder model:

[0187]

[0188] The model input conditions include: C L is the lift coefficient of the rudder; C D is the drag coefficient of the rudder; Λ is the aspect ratio of the rudder; δ is the rudder angle; R n is the Reynolds number of the rudder; C Q v is the prismatic coefficient, which is about 1 when the upper and lower edges of the rudder are sharp; f is the velocity at the rudder, which is 1.25 times the ship's speed; ρ w is the density of seawater; A r is the rudder area; x r is the distance from the rudder to the middle station surface, and the stern rudder takes a negative value;

[0189] The model calculation results are: the longitudinal, transverse and vertical rudder forces X in the coordinate system direction R ,N R ,Y R ;

[0190] S53, the hull module establishes a six-degree-of-freedom motion simulation model for polar ships, takes into account wind loads, wave loads, and the relative speed between the ship and the current, considers the influence of wind, wave, and current environmental conditions on the hull motion, takes into account the total load of flat ice and the total load of crushed ice, considers the influence of ice on the hull motion, takes into account propeller thrust and ship rudder force to control the navigation state of the ship, and obtains the six-degree-of-freedom motion data of the ship through integral calculation;

[0191] The hydrodynamic coefficient and time delay function of the mother ship are calculated according to the mother ship's line, and the six-degree-of-freedom motion simulation model of the ship is established according to the ice conditions and ocean conditions in the broken ice area:

[0192]

[0193] The model input conditions include: M0 is the sum of the mother ship mass and the additional mass; C RB0 is the centripetal force of the rigid body and the fluid, C A0 is the Coriolis force matrix; v r0 is the relative speed of the mother ship and the ocean current in the body coordinate system; D0 is the damping matrix; K0(t-γ) is the time delay function, where t is the simulation time and γ is the integral variable; U is the longitudinal speed of the mother ship; e1 is the longitudinal unit vector; G0 is the stiffness matrix of the mother ship; τ wind0 is the wind load; τ wave0 is the wave load; τ P is the propeller thrust; τ R is the ship's rudder force; τ ice is the total ice load, including the leveling ice load τ pice and crushed ice load τ sice ;

[0194] Solve to obtain the acceleration of polar ship navigation and velocity v0, and the ship's motion posture is obtained through the fourth-order Runge-Kutta integration.

[0195] Step 6: The polar ship navigation visual simulation subsystem performs 3D scene simulation based on the 3D engine Unreal Engine. During the simulation process, the initial position of the ship, the initial distribution of flat ice and broken ice are loaded through the navigation sea area and wind, wave and current environmental conditions released by the trainer software, and the 3D engine is driven to render the ocean environment, atmospheric environment, ice area and ship 3D models to generate a 3D scene; the flat ice boundary and shape in the 3D scene are updated according to the flat ice crushing characteristic data (crushing radius and the opening angle of the ice wedge at the contact point between the ship and ice) calculated in step 3; the distribution of broken ice in the 3D scene is updated according to the broken ice motion data (displacement and rotation of each independent piece of broken ice), and the ship navigation posture in the 3D scene is updated according to the ship motion posture data calculated in step 5.

[0196] Figure 1 and Figure 2Any process or method description in the flowchart described in or otherwise described herein can be understood as representing a module, fragment or portion of a code including one or more executable instructions for implementing the steps of a custom logic function or process, and the scope of the preferred embodiment of the present invention includes other implementations, in which the functions may be performed in a substantially simultaneous manner or in a reverse order according to the functions involved, which should be understood by a person skilled in the art of the present invention. The logic and / or steps represented in the flowchart or otherwise described herein illustrate the possible implementation architecture, functions and operations of the apparatus and methods according to various embodiments of the present disclosure. In this regard, each box in the flowchart or block diagram can represent a module, a program segment, or a part of a code, and the above-mentioned module, program segment, or a part of a code contains one or more executable instructions for implementing the specified logic function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in reverse order, depending on the functions involved. It is also noted that each block in the block diagram or flowchart, and combinations of blocks in the block diagram or flowchart, may be implemented by a dedicated hardware-based system that performs the specified functions or operations, or may be implemented by a combination of dedicated hardware and computer instructions. For example, what may be considered as an ordered list of executable instructions for implementing a logical function may be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other system that can fetch instructions from and execute instructions in an instruction execution system, apparatus, or device).

[0197] Those skilled in the art will appreciate that the above are only preferred embodiments of the present invention, and the various embodiments of the present disclosure and / or the features described in the claims may be combined or combined in various ways, even if such combinations or combinations are not explicitly described in the present disclosure. It is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art may still modify the technical solutions described in the aforementioned embodiments, or perform equivalent substitutions on some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

[0198] Although preferred embodiments of the present invention have been described, additional changes and modifications may be made to these embodiments by those skilled in the art once the basic inventive concepts are known. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A polar ship navigation simulation modeling method, characterized in that: The polar ship navigation simulation modeling method comprises the following steps: Step 1: Set environmental conditions, sea ice conditions, initial position of the ship and expected navigation track through the trainer software and electronic chart software of the integrated management and evaluation subsystem, and issue simulation tasks; Step 2: According to the simulation task released in step 1, the polar environment simulation subsystem calculates the wind, wave and current loads through the wind speed module, wave field module and current velocity module according to the set environmental conditions, and uses a multi-threaded parallel programming method to traverse the boundary points of the ship's waterline surface and the nearby flat ice and broken ice boundary points to detect the ship-ice contact situation; Step 3: Based on the detection of ship-ice contact in step 2, when the ship-ice contact is detected, the ice field module calculates the crushing of smooth ice, the movement of broken ice, and the total load of smooth ice and broken ice according to the ship-smooth ice collision model and the ship-broken ice collision model according to the distribution of sea ice, ice thickness, and material properties; Step 4: The polar ship real-time motion simulation subsystem uses the wind load, wave load, relative speed between the ship and the current, total load of smooth ice, and total load of crushed ice calculated by the polar environment simulation subsystem as environmental load inputs, and uses the rotation speed and rudder angle provided by the polar ship driving control simulation subsystem as control command inputs to respectively establish a propeller model, a rudder model, and a polar ship six-degree-of-freedom motion simulation model; Step 5: The polar ship navigation visual simulation subsystem generates a three-dimensional scene according to the navigation sea area and wind, wave and current environmental conditions released by the trainer software, updates the distribution of flat ice and broken ice according to the flat ice crushing characteristic data and broken ice motion data calculated by the polar environment simulation subsystem, and updates the polar ship navigation simulation three-dimensional scene according to the ship navigation motion data calculated by the polar ship real-time motion simulation subsystem; In step 4, the propeller thrust affected by ice is calculated by using the rotation speed and rudder angle provided by the polar ship driving control simulation subsystem as control instructions; that is, the propeller thrust affected by crushed ice T P The calculation method is: Where: t p is the thrust reduction of the propeller; ρ w is the density of seawater; n p is the propeller speed; D p is the propeller diameter; K T is the thrust coefficient; W p is the wake velocity; u is the relative speed between the ship and the broken ice; T P is the propeller thrust.

2. The polar ship navigation simulation modeling method according to claim 1, characterized in that: Step three also includes calculating the ship-ice contact area, the extrusion pressure and friction force between the ship and the ice, and the bending failure load of the flat ice, judging the breakage of the flat ice, and representing the shape characteristics of the broken ice after the flat ice breaks by the radius of the broken ice and the opening angle of the ice wedge.

3. The polar ship navigation simulation modeling method according to claim 1, characterized in that: In step 3, the ship-ice contact area, the extrusion force and friction force between the ship and the ice, and the bending failure load of the flat ice are calculated to determine the flat ice breakage situation, and the shape characteristics of the broken ice after the flat ice breaks are expressed by the radius of the broken ice and the opening angle of the ice wedge. The specific steps include: S31, first through the ice thickness h i , the angle between the normal direction outside the hull and the downward vertical axis at the point where the ship contacts the ice And extrusion depth L d , determine the shape of the ship-ice contact point, and calculate the contact area A between the ship and the flat ice c , the ship-flat ice collision model is: Among them, L h L is the length of the ship edge in contact with the ice edge on the horizontal ice surface; d is the depth to which the ship is squeezed into the ice boundary on a horizontal ice surface; h is the angle between the normal direction outside the hull and the downward vertical axis at the point where the ship contacts the ice; i is the thickness of the ice layer; S32, secondly, the contact area A between the ship and the flat ice c Calculate the squeeze force F between the ship and ice c and friction F f , the ship-flat ice collision model is: F c =n c ·s c A c F fz =-t c ·m f F c v z / V F fl =-t c ·m f F c v l / V Among them, n c is the unit normal of the ship-ice contact surface; σ c is the compressive strength of ice; τ c is the unit tangent of the ship-ice contact surface; μ f F is the ship-ice friction coefficient; fz is the upward friction along the ship-ice contact surface; v z F is the relative speed of the ship-ice upward along the ship-ice contact surface; fl is the friction force in the horizontal direction along the ship-ice contact surface; v l is the relative speed of the ship to the ice in the horizontal direction of the ship-ice contact surface; V is the total speed of the ship sliding relative to the ice; S33, the total load of the flat ice on the mother ship in the coordinate system is τ pice : in, is the transformation matrix between the local coordinates of the ship-ice contact surface and the hull coordinates; S34. In order to determine the fracture condition and shape characteristics of the flat ice that collides with the hull, calculate the flat ice bending failure load P f , the ship-ice collision model is calculated as: Among them, C f is an empirical parameter; σ f is the ice bending strength; θ is the opening angle of the ice wedge at the ship-ice contact point, h i is the thickness of the ice layer; When the combined force of the ship's ice extrusion force and the friction force in the vertical direction Greater than the bending failure limit load P f When the flat ice breaks, the broken ice falls off; S35. The shape of the broken ice is fan-shaped. The annular crack method is used to express the shape characteristics of the broken ice using the crushing radius and the opening angle of the ice wedge at the ship-ice contact point. The calculation model of the crushing radius R is: Among them, C l , C v is the empirical coefficient, ν is Poisson's ratio, E is the elastic modulus of ice; ρ w is the density of seawater; v n is the relative normal velocity between the discrete point of the waterline and the discrete point of the flat ice boundary; S36. After determining the characteristic crushing radius of the detached ice shape and the opening angle of the ice wedge at the ship-ice contact point, break off the detached ice according to the sea ice distribution published by the instructor software, update the smooth ice boundary, indicate the smooth distribution, and generate a boundary for the ice detached from the smooth ice.

4. The polar ship navigation simulation modeling method according to claim 1, characterized in that: In step 3, when the ship-ice contact is detected, the ice field module calculates the crushing of flat ice, the movement of broken ice, and the total load of flat ice and broken ice according to the ship-flat ice collision model and the ship-broken ice collision model based on the sea ice distribution, ice thickness, and material properties: S311. First, a dynamic model of each piece of ice in the ship's navigation area is established: Among them, F s T is the combined external force generated by the wind, wave and current forces acting on the broken ice and the contact forces with the flat ice, broken ice and the hull. s is the total external torque; m s is the total mass of crushed ice currently calculated; J s is the total inertia tensor; Enter F s , T s 、m s and J s The value of the crushed ice motion velocity vector v s ; Angular velocity vector ω s , the integral obtains the displacement and rotational motion data of each piece of crushed ice, indicating the distribution of crushed ice; S322. The contact between the solid surfaces of crushed ice is calculated using a linear spring damping system. The contact force calculation models of ship-crushed ice, crushed ice-crushed ice, and crushed ice-smooth ice near the hull are: Where k is the elastic coefficient of ice material; η is the damping coefficient of ice material; d n is the normal overlap distance between ice and other objects, v n is the normal overlap velocity, d t is the tangential overlap distance, v t is the tangential overlap velocity, μ is the friction coefficient; n t is the unit direction tangent to the ice-crushing boundary; F n is the normal contact force inward from the ice boundary, F t is the tangential contact force along the ice boundary; S333, the total load of the mother ship on the broken ice in the coordinate system is τ sice : in, is the transformation matrix between the local coordinates of the ship-ice contact surface and the hull coordinates.

5. The polar ship navigation simulation modeling method according to claim 1, characterized in that: The method for establishing the ship's six-degree-of-freedom motion simulation model in step 4 is: Where: M0 is the sum of the mother ship mass and the additional mass; C RB0 is the centripetal force of the rigid body and the fluid, C A0 is the Coriolis force matrix; v r0 is the relative speed of the mother ship and the ocean current in the body coordinate system; D0 is the damping matrix; K0(t-γ) is the time delay function, where t is the simulation time and γ is the integral variable; U is the longitudinal speed of the mother ship; e1 is the longitudinal unit vector; G0 is the stiffness matrix of the mother ship; τ wind0 is the wind load; τ wave0 is the wave load; τ P is the propeller thrust; τ R is the ship's rudder force; τ ice is the total ice load, including the leveling ice load τ pice and crushed ice load τ sice ; Solve to obtain the acceleration of polar ship navigation and velocity v0, and the ship's motion posture is obtained through the fourth-order Runge-Kutta integration.

6. The polar ship navigation simulation modeling method according to claim 1, characterized in that: In step five, the method for the polar ship navigation visual simulation subsystem to generate a three-dimensional scene according to the navigation area and wind, wave and current environmental conditions released by the trainer software is as follows: the polar ship navigation visual simulation subsystem performs three-dimensional scene simulation based on a three-dimensional engine. During the simulation process, the initial position of the ship, the initial distribution of flat ice and broken ice are loaded through the navigation area and wind, wave and current environmental conditions released by the trainer software, and the three-dimensional engine is driven to render the three-dimensional models of the ocean environment, atmospheric environment, ice area and ship to generate a three-dimensional scene.

7. A polar ship navigation simulation system, used to execute the method of claim 1, characterized in that: The polar ship navigation simulation system includes a comprehensive management and evaluation subsystem, a ship driving control simulation subsystem, a polar environment simulation subsystem, a polar ship real-time motion simulation subsystem and a polar ship navigation vision simulation subsystem; The comprehensive management and evaluation subsystem includes trainer software and electronic chart software. The trainer software is used to provide polar environment and ice distribution input conditions for the polar environment simulation subsystem; the electronic chart software is used to provide the polar ship motion simulation subsystem with the initial position of the ship and the route planning in real time, and control the simulation process of the simulation system at the same time; The ship driving control simulation subsystem includes a propeller operation module, a steering gear operation module, and a driving and navigation control module; Used to provide propeller speed, rudder angle and thruster fault control instructions for the polar ship real-time motion simulation subsystem to simulate ship navigation control; The polar environment simulation subsystem includes a wind speed module, a wave field module, a flow rate module, and an ice field module; the wind load, wave load, relative speed between the ship and the current, total load of smooth ice, and total load of crushed ice calculated by the polar environment simulation subsystem are input as environmental loads into the polar ship real-time motion simulation subsystem; the ice field module establishes a ship-smooth ice collision model and a ship-crushed ice collision model, and calculates the crushing of smooth ice, the movement of crushed ice, and the total load of smooth ice and crushed ice; The polar ship real-time motion simulation subsystem includes a propeller module, a rudder module, and a hull module. By establishing a six-degree-of-freedom motion simulation model of the ship, the ship motion considering the influence of wind, waves, currents, and ice loads is calculated; The polar ship navigation visual simulation subsystem receives ice crushing and motion data calculated by the polar environment simulation subsystem and ship motion data calculated by the polar ship real-time motion simulation subsystem, and is used to display and update polar navigation, atmosphere, ocean, and ice field scenes in real time.

8. The polar ship navigation simulation system according to claim 7, characterized in that: The polar ship navigation visual simulation subsystem includes a polar ship motion simulation drive module, a sea ice motion simulation drive module, a polar environment simulation module and a polar navigation auxiliary information display module; The polar ship motion simulation driving module is used to receive and update the motion posture of the polar ship during navigation in real time; The sea ice motion simulation driving module is used to receive and update the distribution of floating ice in the ship's navigation area in real time; The polar environment simulation module is used to synchronously update the polar environment according to the instructor's instructions; The polar navigation auxiliary information display module is used to dynamically display the ice thickness and interference distance in the visual scene.

Images