Method for determining ship collision accident level and predicting traffic flow based on voxel structure

Abstract

The present invention discloses a method for determining the level of a ship collision accident and predicting traffic flow based on a voxel structure, comprising the following steps: S1, obtaining attribute parameters, collision parameters, and AIS parameters of the struck ship; S2, predicting the dynamic changes in water flow velocity using the AIS parameters, hydrological parameters, and a three-dimensional model of the channel bottom of the struck ship; S3, constructing a collision motion equilibrium equation, and using a numerical method to calculate the instantaneous impact force and impact torque at different impact points of the struck ship to determine the collision accident level; S4, coupling the data output by the three-dimensional channel model and the three-dimensional ship collision model to predict the trend and duration of the motion state change of the struck ship. By numerically simulating the struck ship and predicting the dynamic changes in water flow velocity, the trend and duration of the motion state change of the struck ship are predicted, reflecting the future trend of traffic flow changes in the channel, and providing a theoretical basis for the rational reclassification of channels or guidance of virtual channels in the future.

Description

Technical Field

[0001] The present invention relates to the field of ship traffic technology, and in particular to a method for determining the level of ship collision accidents and predicting traffic flow based on a voxel structure. Background Art

[0002] Ship accidents can cause serious economic losses, environmental pollution, and casualties. Therefore, ship safety has always been a focus of research and attention. The ship collision process is an extremely complex nonlinear dynamic response process, which is affected by the ship itself, its motion state, and the channel conditions.

[0003] Existing ship collision models lack the ability to account for ship motion in the Z direction and rotation around the X and Y axes. This lacks the necessary calculation of the added mass coefficients associated with a ship's motion in the water, resulting in inaccurate predictions of ship collisions. Furthermore, existing models are unable to analyze the changing motion trends of the impacted ship and make predictions about future traffic flows.

[0004] Therefore, it is necessary to improve the calculation model of ship collision in the existing technology to solve the above problems. Summary of the Invention

[0005] The present invention overcomes the deficiencies of the prior art and provides a method for determining the level of a ship collision accident and predicting traffic flow based on a voxel structure.

[0006] To achieve the above-mentioned object, the technical solution adopted by the present invention is: a method for determining the level of ship collision accidents and predicting traffic flow based on voxel structure, comprising the following steps:

[0007] S1. Divide the waterway into two sub-channels with the navigation separation line as the center, and divide each sub-channel into several virtual channels; obtain real-time traffic flow data within the channel within the radiation range after the ship collision accident; obtain the attribute parameters, collision parameters and AIS parameters of the struck ship, and obtain the waterway hydrological parameters;

[0008] S2. using the AIS parameters and hydrological parameters of the struck vessel, combined with a three-dimensional model of the channel bottom at the location of the struck vessel, to predict the dynamic changes in the water flow velocity in the hydrological parameters within a predetermined time;

[0009] S3. Establish a three-dimensional ship collision model based on the attribute parameters of the struck ship and the impact parameters, perform numerical simulation on the struck ship, construct the collision motion equilibrium equation, calculate the instantaneous impact force and impact torque at different impact points of the struck ship based on numerical methods, and determine the collision accident level;

[0010] S4. The data output from the three-dimensional channel model and the three-dimensional ship collision model are coupled, and the phase space reconstruction algorithm based on Takens' theorem and the SVR prediction model are used to predict the change trend and duration of the motion state of the struck ship, and further predict the traffic flow.

[0011] In a preferred embodiment of the present invention, the attribute parameters are parameters of the model, deadweight, load, normal speed and real-time draft line; the impact parameters are parameters of the impact angle, impact point and impact speed; the AIS parameters are parameters of the real-time latitude and longitude of the impacted ship; and the hydrological parameters are parameters of wind speed, wind direction, water flow velocity and water flow direction.

[0012] In a preferred embodiment of the present invention, during the numerical simulation of the struck ship, the collision motion equilibrium equation includes analysis of the X, Y and Z directions of the struck ship, as well as the rotation of the impact point of the struck ship around the X, Y and Z axes, to obtain simulated impact force, impact torque and motion state changes.

[0013] In a preferred embodiment of the present invention, the collision motion equilibrium equation is:

[0014]

[0015] Among them, i∈N+,M i is the mass of the i-th impact point on the outer contour of the ship; m xi 、m yi and m zi are the additional mass coefficients of motion in the X, Y and Z directions of the i-th impact point on the outer contour of the ship, respectively, xi is the impact acceleration of the i-th impact point, F x 、F y and F z are the impact forces in the X, Y and Z directions respectively; μ xi 、μ yi and μ zi are the friction coefficients in the X, Y and Z directions of the i-th impact point, ω xi 、ω yi and ω zi are the angular velocities of the i-th impact point in the X, Y and Z directions, R xi 、R yi and R zi are the rotation radii of the i-th impact point in the X, Y and Z directions, M x 、M y and M z are the external moments in the X, Y and Z directions respectively.

[0016] In a preferred embodiment of the present invention, the determination of the impact point and impact angle;

[0017] The impact point is a different part assigned to the outer contour of the ship. Specifically, the struck ship is classified, and the center of the struck ship is taken as point O. A two-dimensional coordinate is established, and several rays are drawn from point O. The connection points of the several rays and the outer contour of the struck ship are formed as the impact points.

[0018] The impact angle is the angle formed by the tangent of the contact surface of the outer contour of the impacting ship and the tangent of the impact point; the rotational angular velocity of the impacted point located in the first quadrant and the third quadrant is positive, and the rotational angular velocity of the impacted point located in the second quadrant and the fourth quadrant is negative.

[0019] In a preferred embodiment of the present invention, the maximum movement speed of the struck ship and the water flow after the collision is determined based on the normal speed of the struck ship and the change in the distance between the center of the ship and the center line of the virtual channel after the collision, and the collision speed is determined in combination with the collision point and collision angle.

[0020] In a preferred embodiment of the present invention, the standard draft line is obtained by the model, deadweight, load and real-time longitude and latitude of the struck ship, and the vertical distance from the lower edge of the flat keel to the standard draft line of the impact point of the struck ship is determined.

[0021] In a preferred embodiment of the present invention, a plurality of gyroscopes are provided on the bottom of the struck ship corresponding to the impact points in the first quadrant, the second quadrant, the third quadrant and the fourth quadrant, and at least two gyroscopes are provided in each quadrant.

[0022] In a preferred embodiment of the present invention, the wind speed, wind direction, water flow velocity, and water flow direction in the hydrological parameters cause the struck ship to generate dynamic self-flow or drift after losing its self-control ability, and the time used for this dynamic self-flow or drift process is the duration.

[0023] In a preferred embodiment of the present invention, the accident is divided into: head-on collision, cross-over collision and overtaking collision according to the collision situation of the struck ship.

[0024] The present invention solves the defects existing in the background technology and has the following beneficial effects:

[0025] (1) The present invention provides a method for determining the level of ship collision accidents and predicting traffic flow. By numerically simulating the impacted ship and predicting the dynamic changes in water flow velocity, the trend of changes in the motion state and the duration of the impacted ship can be predicted. The future trend of changes in traffic flow in the radial channel can be comprehensively and intuitively reflected, providing a theoretical basis for the reasonable reclassification of channels or guidance of virtual channels in the future.

[0026] (2) In the numerical simulation process of the struck ship in this embodiment of the present invention, the collision motion equilibrium equation includes analysis of the X, Y and Z directions of the struck ship, as well as the rotation of the impact point of the struck ship around the X, Y and Z axes, thereby obtaining simulated impact force, impact torque and motion state change, thereby solving the problems in the prior art of lacking the Z-direction motion of the ship and the rotation of the ship around the X and Y axes, and lacking the corresponding additional mass coefficient when the struck ship moves in water.

[0027] (3) The present invention utilizes the principle of voxel structure to simplify the motion state changes of a ship collision into a plurality of voxel structures. Voxels refer to the impact force, impact torque, hydrological parameters in the three-dimensional model of the channel bottom, impact angle, impact point, impact speed and AIS parameters. By accurately calculating or predicting each individual voxel or the voxels with connections, the motion state changes of the ship after the collision are predicted, and the traffic flow is further predicted.

[0028] (4) The present invention constructs a three-dimensional model of the channel bottom based on the water flow and sediment volume in the corresponding channel in the database. By detecting the sediment height and water flow velocity at the bottom of the channel, a three-dimensional model of the bottom corresponding to the channel position of the struck ship is constructed. By combining real-time hydrological parameters, the dynamic suspension state of sediment volume over a period of time is analyzed, and the dynamic changes in water flow velocity in the channel within the radiation range after the ship collision accident are predicted. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments described in the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive efforts.

[0030] Figure 1 It is a flow chart of a method for determining the level of a ship collision accident and predicting traffic flow according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0033] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the scope of protection of this application. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0034] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections; they can refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0035] The following describes a method for determining the level of a ship collision accident and predicting traffic flow based on a voxel structure provided by an embodiment of the present invention.

[0036] The change in motion state after a ship collision is an extremely complex nonlinear dynamic response process. It is affected by the ship itself, its motion state, and the channel conditions. There are a large number of geometric nonlinearity, material nonlinearity, motion nonlinearity, and contact nonlinearity problems, as well as the collision of the attached water around the ship. In the embodiment of the present invention, the voxel structure refers to the complex object being constructed by a number of simple entities through orderly Boolean operations, and these simple entities are voxels. In this embodiment, the complex object refers to the change in motion state after the impact of the ship, and the voxels refer to the impact force, impact torque, hydrological parameters in the three-dimensional model of the channel bottom, impact angle, impact point, impact speed, and AIS parameters. By accurately calculating or predicting each individual voxel or the connections between voxels, the change in motion state after the impact of the ship is predicted, and the traffic flow is further predicted.

[0037] According to the collision situation of the struck ship, the accident is divided into: ship head-on collision, ship crossing collision and ship overtaking collision.

[0038] In this embodiment, the struck ship is set as a ship that needs to determine the accident level to perform the various steps in this embodiment. Before performing this embodiment, those skilled in the art have the ability to know the location of the waterway where the accident occurred through AIS parameters.

[0039] Please refer to Figure 1 The method for determining the ship collision accident level and predicting traffic flow in an embodiment of the present invention includes the following steps:

[0040] S1. Channel construction and data collection: With the navigation separation line as the center, the channel is divided into two sub-channels in two directions, and each sub-channel is divided into several virtual channels; real-time traffic flow data within the channel within the radiation range after the ship collision accident occurs is obtained; attribute parameters of the struck ship, collision parameters and AIS parameters are obtained, and the channel hydrological parameters are obtained;

[0041] The waterway in this embodiment specifically refers to a river, lake or ocean that can allow the ship to withstand the draft depth under the maximum load. In this embodiment, the entire waterway is divided into two traffic flow directions, and each virtual waterway is not limited in number.

[0042] This embodiment collects traffic flow in a waterway within a certain radiation range where a ship traffic accident occurs. The collection method is satellite positioning or sensor collection, so as to determine the traffic flow position, traffic flow density and traffic flow speed before and after the ship traffic accident.

[0043] This embodiment obtains attribute parameters, impact parameters, and AIS parameters of the struck ship, wherein the attribute parameters include model, deadweight, load, normal speed, and real-time draft line parameters.

[0044] The impact parameters are the parameters of the impact angle, impact point and impact speed, and the AIS parameters are the parameters of the real-time latitude and longitude of the impacted ship.

[0045] Among them, the impact point is the different parts assigned to the outer contour of the ship. Specifically: the struck ship is classified, the center of the struck ship is taken as point O, a two-dimensional coordinate is established, and several rays are drawn from point O. The connection points of several rays and the outer contour of the struck ship form the impact points.

[0046] The impact angle is the angle formed by the tangent to the contact surface of the striking vessel's outer contour and the tangent to the point of impact. The angular velocity of the impacted point in the first and third quadrants is positive, while the angular velocity of the impacted point in the second and fourth quadrants is negative.

[0047] A plurality of gyroscopes are arranged on the bottom of the struck ship corresponding to the impact points in the first quadrant, the second quadrant, the third quadrant and the fourth quadrant, and at least two gyroscopes are arranged in each quadrant.

[0048] According to the normal speed of the struck ship and the change in the distance between the center of the ship and the center line of the virtual channel after the collision, the maximum movement speed of the struck ship and the water flow after the collision is determined, and the impact speed is determined in combination with the impact point and impact angle.

[0049] After a collision, a struck vessel's speed increases briefly before gradually stabilizing. During this stabilization process, as the impact energy dissipates and the water flow acts, it generates dynamic self-flow or drift, which impacts traffic flow. The impact velocity is determined by combining the displacement of the struck vessel within a short period of time with the impact point and angle.

[0050] Hydrological parameters include wind speed, wind direction, current velocity, and current direction. These parameters can be collected by sensors installed on the top deck of the struck vessel, or by relevant departments based on AIS data positioning and information released. This embodiment does not limit the method for obtaining real-time hydrological parameters.

[0051] S2. using the AIS parameters and hydrological parameters of the struck vessel, combined with a three-dimensional model of the channel bottom at the location of the struck vessel, to predict the dynamic changes in the water flow velocity in the hydrological parameters within a predetermined time;

[0052] The 3D model of the channel bottom is constructed based on the water flow and sediment load in the corresponding channel in the database. By detecting the sediment height and water velocity at the channel bottom, a 3D model of the channel bottom corresponding to the location of the struck ship is constructed. By combining real-time hydrological parameters, the dynamic state of sediment suspension over time is analyzed, and the dynamic changes in water velocity within the channel radius after the ship collision are predicted.

[0053] S3. Establish a three-dimensional ship collision model based on the attribute parameters of the struck ship and the impact parameters, perform numerical simulation on the struck ship, construct the collision motion equilibrium equation, calculate the instantaneous impact force and impact torque at different impact points of the struck ship based on the numerical method, and determine the collision accident level.

[0054] This example uses MSC.DYTRAN software to model the impacted ship based on parameters such as the ship's deadweight, load, normal speed, and impact angle external linearity. The impact process and dynamic changes are numerically simulated. The impact force and motion state changes are analyzed and compared with theoretical calculation results.

[0055] In the numerical simulation process of the struck ship in this embodiment, the collision motion equilibrium equation includes analysis of the X, Y, and Z directions of the struck ship, as well as the rotation of the impact point of the struck ship around the X, Y, and Z axes, to obtain simulated impact force, impact torque, and motion state changes.

[0056] Among them, the external mechanism of ship collision is studied. Based on the analytical method of three-dimensional motion, a system of relationships between the energy dissipation and collision force of the ship after the collision is obtained. The equilibrium equation of the collision motion is:

[0057]

[0058] Among them, i∈N+,M i is the mass of the i-th impact point on the outer contour of the ship; m xi 、m yi and m zi are the additional mass coefficients of motion in the X, Y and Z directions of the i-th impact point on the outer contour of the ship, respectively, xi is the impact acceleration of the i-th impact point, F x 、F y and F z are the impact forces in the X, Y and Z directions respectively; μ xi 、μ yi and μ zi are the friction coefficients in the X, Y and Z directions of the i-th impact point, ω xi 、ω yi and ω zi are the angular velocities of the i-th impact point in the X, Y and Z directions, R xi 、R yi and R zi are the rotation radii of the i-th impact point in the X, Y and Z directions, M x 、M y and M z are the external moments in the X, Y and Z directions respectively.

[0059] This embodiment further deduces the ship mechanism analysis formula by considering possible sliding situations caused by factors such as collision angle and collision position; the numerical method based on the time-step integration of the transient motion equation takes into account the changes in the ship collision force and energy absorption with the impact angle, impact speed, impact position, etc., and can thus perform a detailed simulation of the entire process of ship collision.

[0060] In this embodiment, the motion additional mass coefficient is determined as follows: considering the impact point and the direction of the water flow, the motion additional mass coefficient m is calculated using the following formula: Where ρ is the fluid density, s is the area of the impact point, γ is the fluid reduction factor, ranging from 0.3 to 0.8, h1 is the draft, and h2 is the distance between the impact point and the water surface. The standard draft line is obtained using the cross-section, deadweight, load, and real-time longitude and latitude of the impacted vessel model. The vertical distance h2 from the lower edge of the flat keel to the standard draft line in the middle of the impacted vessel is determined.

[0061] S4. The data output from the three-dimensional channel model and the three-dimensional ship collision model are coupled, and the phase space reconstruction algorithm based on Takens' theorem and the SVR prediction model are used to predict the change trend and duration of the motion state of the struck ship, and further predict the traffic flow.

[0062] During data coupling, considering that the dimensions of the parameter time series of the struck ship are inconsistent, the parameter time series need to be normalized to the same range.

[0063] The wind speed, wind direction, water flow velocity and water flow direction in the hydrological parameters cause the struck ship to produce dynamic self-flow or drift after losing its self-control ability. The time used for this dynamic self-flow or drift process is the duration.

[0064] By predicting the changing trend and duration of the motion state of the struck ship, the future changing trend of the traffic flow in the radial channel can be comprehensively and intuitively reflected, providing a theoretical basis for the reasonable reclassification of channels or guidance of virtual channels in the future.

[0065] The above description is based on the ideal embodiment of the present invention. Based on the above description, relevant personnel can make various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the content of the specification and must be determined according to the scope of the claims.

Claims

1. A method for determining the level of ship collision accidents and predicting traffic flow based on voxel structure, characterized in that: The following steps are involved: S1. Divide the waterway into two sub-channels with the navigation separation line as the center, and divide each sub-channel into several virtual channels; obtain real-time traffic flow data within the channel within the radiation range after the ship collision accident; obtain the attribute parameters, collision parameters and AIS parameters of the struck ship, and obtain the waterway hydrological parameters; S2. using the AIS parameters and hydrological parameters of the struck vessel, combined with a three-dimensional model of the channel bottom at the location of the struck vessel, to predict the dynamic changes in the water flow velocity in the hydrological parameters within a predetermined time; S3. Establish a three-dimensional ship collision model based on the attribute parameters of the struck ship and the impact parameters, perform numerical simulation on the struck ship, construct the collision motion equilibrium equation, calculate the instantaneous impact force and impact torque at different impact points of the struck ship based on numerical methods, and determine the collision accident level; During the numerical simulation of the struck ship, the collision motion equilibrium equation includes analysis of the X, Y and Z directions of the struck ship, as well as the rotation of the struck ship around the X, Y and Z axes, to obtain the simulated impact force, impact torque and motion state change; The collision motion equilibrium equation is: in, , is the mass of the i-th impact point on the outer contour of the ship; 、 and are the motion additional mass coefficients in the X, Y and Z directions of the i-th impact point on the outer contour of the ship, is the impact acceleration of the i-th impact point, 、 and are the friction coefficients in the X, Y and Z directions of the i-th impact point, 、 and The i-th impact point The angular velocity of rotation, 、 and are the rotation radii of the i-th impact point in the X, Y and Z directions, 、 and They are external torque; S4. The data output from the three-dimensional channel model and the three-dimensional ship collision model are coupled, and the phase space reconstruction algorithm based on Takens' theorem and the SVR prediction model are used to predict the change trend and duration of the motion state of the struck ship, and further predict the traffic flow.

2. The method for determining the ship collision accident level and predicting traffic flow based on voxel structure according to claim 1, characterized in that: The attribute parameters include the model, deadweight, load, normal speed and real-time draft line parameters; the impact parameters include the impact angle, impact point and impact speed parameters; the AIS parameters include the real-time latitude and longitude parameters of the impacted ship; and the hydrological parameters include the wind speed, wind direction, water flow velocity and water flow direction parameters.

3. The method for determining the ship collision accident level and predicting traffic flow based on voxel structure according to claim 1, characterized in that: Determination of the impact point and impact angle; The impact point is a different part assigned to the outer contour of the ship. Specifically, the struck ship is classified, and the center of the struck ship is taken as point O. A two-dimensional coordinate is established, and several rays are drawn from point O. The connection points of the several rays and the outer contour of the struck ship are formed as the impact points. The impact angle is the angle formed by the tangent of the contact surface of the outer contour of the impacting ship and the tangent of the impact point; the rotational angular velocity of the impacted point located in the first quadrant and the third quadrant is positive, and the rotational angular velocity of the impacted point located in the second quadrant and the fourth quadrant is negative.

4. The method for determining the ship collision accident level and predicting traffic flow based on voxel structure according to claim 2, characterized in that: According to the normal speed of the struck ship and the change in the distance between the center of the ship and the center line of the virtual channel after the collision, the maximum movement speed of the struck ship and the water flow after the collision is determined, and the impact speed is determined in combination with the impact point and impact angle.

5. The method for determining the ship collision accident level and predicting traffic flow based on voxel structure according to claim 2, characterized in that: The standard draft line is obtained through the model, deadweight, load and real-time longitude and latitude of the struck ship, and the vertical distance from the lower edge of the flat keel to the standard draft line of the impact point of the struck ship is determined.

6. The method for determining the ship collision accident level and predicting traffic flow based on voxel structure according to claim 3, characterized in that: A plurality of gyroscopes are arranged on the bottom of the struck ship corresponding to the impact points in the first quadrant, the second quadrant, the third quadrant and the fourth quadrant, and at least two gyroscopes are arranged in each quadrant.

7. The method for determining the ship collision accident level and predicting traffic flow based on voxel structure according to claim 2, characterized in that: The wind speed, wind direction, water flow velocity and water flow direction in the hydrological parameters cause the struck ship to produce dynamic self-flow or drift after losing its self-control ability. The time used for this dynamic self-flow or drift process is the duration.

8. The method for determining the ship collision accident level and predicting traffic flow based on voxel structure according to claim 1 is characterized by: According to the collision situation of the struck ship, the accident is divided into: ship head-on collision, ship crossing collision and ship overtaking collision.

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