UUV docking control method and device based on direct numerical simulation algorithm, and medium

Abstract

The invention discloses a UUV docking control method and device based on a direct numerical simulation algorithm and a medium, and relates to the technical field of underwater vehicle control, and the method comprises the steps: obtaining wake flow field information corresponding to a mother boat at the current moment; carrying out area score calculation on the wake flow field information based on a UUV surface grid to obtain a hydrodynamic parameter of the UUV; the motion speed of the UUV at the next moment is obtained based on the hydrodynamic parameters; the docking mode of the UUV docking mother boat at the current moment is determined; and controlling to reduce the to-be-controlled component velocity corresponding to the docking mode, calculating the motion displacement at the next moment based on the controlled motion velocity, and returning to execute the step of acquiring the wake flow field information of the mother boat at the current moment until the UUV and the mother boat are docked. The method and the device are used for solving the problems of low precision and low efficiency during UUV docking process control in the prior art, and realizing quick and accurate docking control of the UUV and the mother boat.

Description

Technical Field

[0001] The present application relates to the field of underwater vehicle control technology, and in particular to a UUV docking control method, device and medium based on a direct numerical simulation algorithm. Background Art

[0002] At present, underwater vehicles (UUVs) are widely used in military marine technology, marine science and technology surveys, seabed exploration, pipeline maintenance, seabed salvage, etc. Among them, UUVs generally use their own energy when operating, and their working time and navigation distance are limited. They need to be recovered and docked for energy replenishment.

[0003] The UUV docking process test is difficult and costly. Currently, the UUV docking process is evaluated through simulation technology. There are two main types of simulation analysis of the UUV docking process: mathematical model simulation and direct numerical simulation. The former mainly uses linear theoretical assumptions to simulate its motion process with the help of mathematical models. Although this method has a small amount of calculation, it ignores the influence of fluid viscosity, resulting in low prediction accuracy and poor prediction accuracy. The latter is based on dynamic grid technology and overlapping grid technology to perform direct numerical simulation of the docking of UUV and mothership. Although this method has high calculation accuracy, due to the use of body-fitting grids, the number of grids is large, so huge computing resources need to be configured. The overall computing resource consumption is large and the computing efficiency is low. In addition, the grid must be deformed during the docking process to realize the movement of the UUV, but the deformation of the grid to a certain extent will cause the calculation to diverge and the calculation cannot continue. Summary of the invention

[0004] In response to the above-mentioned problems and technical needs, the applicant has proposed a UUV docking control method, equipment and medium based on a direct numerical simulation algorithm to solve the problems of low accuracy and low efficiency in the prior art when controlling the UUV docking process, and to achieve fast and accurate docking control between the UUV and the mother ship.

[0005] The embodiment of the present application provides a UUV docking control method based on a direct numerical simulation algorithm, the method comprising:

[0006] Obtain the wake field information corresponding to the mother ship at the current moment, wherein the UUV is in the wake field of the mother ship, and the mother ship surface grid corresponding to the mother ship and the UUV surface grid corresponding to the UUV are within the Cartesian grid corresponding to the calculation domain, and the calculation domain is obtained based on the size characteristics of the mother ship;

[0007] Performing surface integral calculation on the wake field information based on the UUV surface grid to obtain the hydrodynamic parameters of the UUV, wherein the hydrodynamic parameters include: longitudinal force, lateral force, vertical force, rolling moment, yaw moment and pitch moment;

[0008] The motion speed of the UUV at the next moment is obtained based on the hydrodynamic parameters, wherein the motion speed includes six component speeds, and the six component speeds include: longitudinal linear speed, lateral linear speed, vertical linear speed, roll angular speed, yaw angular speed and pitch angular speed;

[0009] Determine the relative position relationship between the UUV and the mothership, and determine the docking mode of the UUV to dock with the mothership at the current moment based on the phase position relationship;

[0010] The speed of the component to be controlled corresponding to the docking mode is controlled to be reduced, and the motion displacement at the next moment is calculated based on the controlled motion speed, and the step of obtaining the wake field information of the mother ship at the current moment is returned to execute until the UUV completes the docking with the mother ship, wherein the motion displacement includes six component displacements, and the six component displacements include: longitudinal line displacement, lateral line displacement, vertical line displacement, roll angle displacement, yaw angle displacement and pitch angle displacement, and the relative position relationship at the next moment is obtained based on the motion displacement, and there is a preset mapping relationship between the docking mode and the component speed to be controlled.

[0011] According to the UUV docking control method based on the direct numerical simulation algorithm provided in the embodiment of the present application, the docking mode includes: any one or more of the longitudinal docking mode, the vertical docking mode and the lateral docking mode;

[0012] Controlling and reducing the speed of the component to be controlled corresponding to the docking mode includes:

[0013] When it is determined that the docking mode is the longitudinal docking mode, controlling to reduce the lateral linear speed and the vertical linear speed;

[0014] When it is determined that the docking mode is the vertical docking mode, controlling to reduce the longitudinal line speed and the lateral line speed;

[0015] When it is determined that the docking mode is the transverse docking mode, the longitudinal line speed and the vertical line speed are controlled to be reduced.

[0016] According to the UUV docking control method based on the direct numerical simulation algorithm provided in the embodiment of the present application, the movement speed of the UUV at the next moment is obtained based on the hydrodynamic parameters, including:

[0017] Based on the hydrodynamic parameters and the pre-created UUV motion equation, the acceleration corresponding to the UUV at the current moment is obtained, wherein the UUV motion equation is obtained based on Newton's second law;

[0018] Based on the acceleration and the current speed, the speed of the UUV at the next moment is obtained. According to the UUV docking control method based on the direct numerical simulation algorithm provided by the embodiment of the present application, before obtaining the wake field information corresponding to the mother ship at the current moment, it also includes:

[0019] Obtaining a UUV geometric model of the UUV and a mothership geometric model of a mothership corresponding to the UUV;

[0020] Extracting the size characteristics of the mother ship geometric model to obtain a calculation domain corresponding to the UUV geometric model and the mother ship geometric model;

[0021] The computational domain is meshed based on a Cartesian mesh generation method to obtain the Cartesian mesh, and the UUV geometric model and the mother ship geometric model are meshed based on a surface mesh generation method to obtain a surface mesh, wherein the surface mesh includes: the UUV surface mesh and the mother ship surface mesh.

[0022] According to the UUV docking control method based on the direct numerical simulation algorithm provided in the embodiment of the present application, the method further includes:

[0023] During the UUV docking process, interpolation calculation is performed on the mother ship surface grid, the UUV surface grid and the Cartesian grid;

[0024] The formulas used for interpolation calculation include:

[0025]

[0026] Among them, f(x k ) represents x k Force corresponding to the first grid point in the mothership surface grid and / or UUV surface grid, x k represents the first grid point in the mother ship surface grid and / or the UUV surface grid, (i, j) represents any second grid point in the Cartesian grid, F(i, j) represents the corresponding force on the second grid point, ds represents the distance between the first grid point and the nearest second grid point, and h represents the preset size, which is a constant.

[0027] According to the UUV docking control method based on direct numerical simulation algorithm provided in the embodiment of the present application, when the mother ship is in a stationary state, f(x k ) represents the force corresponding to the first grid point in the UUV surface grid;

[0028] The wake field information is surface-integrated based on the UUV surface grid to obtain the hydrodynamic parameters of the UUV, including:

[0029] Based on the wake field information, the force corresponding to the first grid point in the UUV surface grid is integrated and calculated to obtain the hydrodynamic parameters of the UUV.

[0030] According to the UUV docking control method based on the direct numerical simulation algorithm provided by the embodiment of the present application, before the interpolation calculation of the mother ship surface grid and the UUV surface grid and the Cartesian grid is performed, the method further includes:

[0031] A target grid point is extracted from the Cartesian network, and the target grid point is determined as the second grid point.

[0032] Extracting target grid points from the Cartesian network includes:

[0033] For each first grid point, perform the following extraction operation:

[0034] Acquire the first grid point and a plurality of second grid points adjacent to the first grid point to obtain a target vector;

[0035] Determining an out-of-bounds normal vector corresponding to the target vector;

[0036] Calculate the product of the target vector and the normal vector outside the boundary to obtain a determination value;

[0037] The second grid point whose determination value is greater than zero is used as the target grid point.

[0038] An embodiment of the present application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the steps of the UUV docking control method based on the direct numerical simulation algorithm as described above are implemented.

[0039] An embodiment of the present application also provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of the UUV docking control method based on a direct numerical simulation algorithm as described above are implemented.

[0040] The UUV docking control method, device and medium based on the direct numerical simulation algorithm provided in the embodiments of the present application interact with each other through interpolation between two sets of networks (the mother ship surface grid corresponding to the mother ship and the UUV surface grid corresponding to the UUV in the Cartesian grid corresponding to the calculation domain), and there is no problem of grid deformation and distortion. On the basis of ensuring the calculation accuracy, the consumption of computing resources is reduced and the calculation speed is improved.

[0041] In addition, the wake field information is calculated based on the surface integral of the UUV surface grid to obtain the hydrodynamic parameters of the UUV; the motion speed of the UUV at the next moment is obtained based on the hydrodynamic parameters; the relative position relationship between the UUV and the mother ship is determined, and based on the phase position relationship, the docking mode of the UUV docking with the mother ship at the current moment is determined; the speed of the component to be controlled corresponding to the docking mode is controlled to reduce, and the motion displacement at the next moment is calculated based on the controlled motion speed, and the step of obtaining the wake field information of the mother ship at the current moment is returned to execute until the UUV completes the docking with the mother ship, and the UUV is controlled in real time through the motion parameters (motion speed and motion displacement) of the UUV and the mother ship and the relative position relationship between the UUV and the mother ship to achieve safe docking of the UUV and the mother ship. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0043] Figure 1 It is a flow chart of a UUV docking control method based on a direct numerical simulation algorithm provided in an embodiment of the present application;

[0044] Figure 2 It is a schematic diagram of the calculation domain provided in the embodiment of the present application;

[0045] Figure 3 is a schematic diagram of a surface mesh provided in an embodiment of the present application;

[0046] Figure 4 It is a relative position schematic diagram provided in the embodiment of the present application;

[0047] Figure 5 It is the mother ship geometric model provided in the embodiment of the present application;

[0048] Figure 6 is the UUV geometric model provided in the embodiment of the present application;

[0049] Figure 7 are two sets of grid interpolation schematic diagrams provided in the embodiments of the present application;

[0050] Figure 8 It is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] The embodiment of the present application provides a UUV docking control method based on a direct numerical simulation algorithm. The method can be applied to a smart terminal, a server, or a controller of an underwater vehicle. The present application uses the method applied to the controller of an underwater vehicle as an example for explanation, and some other descriptions in the embodiment are for illustrative purposes only and are not used to limit the scope of protection of the present application, and will not be described one by one later. The specific implementation of the method is as follows Figure 1 As shown:

[0053] Step 101, obtaining the wake field information corresponding to the mother ship at the current moment.

[0054] The wake field information includes wake field velocity and wake field pressure.

[0055] Among them, the UUV is in the wake field of the mother ship, the mother ship surface grid corresponding to the mother ship and the UUV surface grid corresponding to the UUV are in the Cartesian grid corresponding to the calculation domain, and the calculation domain is obtained based on the size characteristics of the mother ship.

[0056] Among them, through Figure 2 Schematic diagram showing the computational domain, including a Cartesian grid diagram. Figure 3 Schematic diagram illustrating a surface mesh.

[0057] Step 102 , performing surface integral calculation on the wake field information based on the UUV surface grid to obtain the hydrodynamic parameters of the UUV.

[0058] Among them, the hydrodynamic parameters include: longitudinal force, lateral force, vertical force, rolling moment, yaw moment and pitch moment.

[0059] Step 103, obtaining the movement speed of the UUV at the next moment based on the hydrodynamic parameters.

[0060] The motion speed includes six component speeds, including longitudinal linear speed, lateral linear speed, vertical linear speed, roll angular speed, yaw angular speed and pitch angular speed.

[0061] Step 104, determining the relative position relationship between the UUV and the mother ship, and determining the docking mode of the UUV to the mother ship at the current moment based on the phase position relationship.

[0062] Step 105, control to reduce the speed of the component to be controlled corresponding to the docking mode, calculate the motion displacement at the next moment based on the controlled motion speed, and return to execute the step of obtaining the wake field information of the mother ship at the current moment until the UUV completes the docking with the mother ship.

[0063] Among them, the motion displacement includes six component displacements, which include: longitudinal line displacement, lateral line displacement, vertical line displacement, roll angle displacement, yaw angle displacement and pitch angle displacement. The relative position relationship at the next moment is obtained based on the motion displacement. There is a preset mapping relationship between the docking method and the speed of the component to be controlled.

[0064] The UUV docking control method based on the direct numerical simulation algorithm provided in the embodiment of the present application performs the interaction of calculation information through interpolation between two sets of networks (the mother ship surface grid corresponding to the mother ship and the UUV surface grid corresponding to the UUV in the Cartesian grid corresponding to the calculation domain), and there is no problem of grid deformation and distortion. On the basis of ensuring the calculation accuracy, the consumption of computing resources is reduced and the calculation speed is improved.

[0065] In addition, the wake field information is calculated based on the surface integral of the UUV surface grid to obtain the hydrodynamic parameters of the UUV; the motion speed of the UUV at the next moment is obtained based on the hydrodynamic parameters; the relative position relationship between the UUV and the mother ship is determined, and based on the phase position relationship, the docking mode of the UUV docking with the mother ship at the current moment is determined; the speed of the component to be controlled corresponding to the docking mode is controlled to reduce, and the motion displacement at the next moment is calculated based on the controlled motion speed, and the step of obtaining the wake field information of the mother ship at the current moment is returned to execute until the UUV completes the docking with the mother ship, and the UUV is controlled in real time through the motion parameters (motion speed and motion displacement) of the UUV and the mother ship and the relative position relationship between the UUV and the mother ship to achieve safe docking of the UUV and the mother ship.

[0066] Among them, through Figure 4 , taking longitudinal docking as an example, the relative position relationship is illustrated, where S represents the distance between the UUV and the mother ship.

[0067] In a specific embodiment, before obtaining the wake field information corresponding to the mother ship at the current moment, the UUV geometric model of the UUV and the mother ship geometric model of the mother ship corresponding to the UUV are obtained; the size characteristics of the mother ship geometric model are extracted to obtain the calculation domain corresponding to the UUV geometric model and the mother ship geometric model; the calculation domain is meshed based on the Cartesian mesh generation method to obtain a Cartesian mesh, and the UUV geometric model and the mother ship geometric model are meshed based on the surface mesh generation method to obtain a surface mesh.

[0068] Among them, the surface mesh includes: UUV surface mesh and mother ship surface mesh.

[0069] Specifically, the UUV and the mother ship's line drawings or value tables are physically modeled to obtain the UUV geometric model and the mother ship geometric model. The UUV geometric model includes: the UUV's main body, control surfaces and thrusters, etc., and the mother ship geometric model includes: the mother ship's main body and control surfaces, etc. This can be achieved specifically through modeling software.

[0070] The geometric model of the mother ship can be found in Figure 5 , UUV geometry model see Figure 6 .

[0071] exist Figure 5 In the figure, 1 is the main body of the mother boat, 2 is the hull of the mother boat, 3-1 is a rudder of the hull of the mother boat, 3-2 is another rudder of the hull of the mother boat, 4-1 is the upper vertical rudder of the mother boat, 4-2 is the lower vertical rudder of the mother boat, 4-3 is the left horizontal rudder of the mother boat, and 4-4 is the right horizontal rudder of the mother boat.

[0072] exist Figure 6 In the figure, 5 is the main body of the UUV, 6-1 is the upper vertical rudder of the UUV, 6-2 is the lower vertical rudder of the UUV, 6-3 is the left horizontal rudder of the UUV, and 6-4 is the right horizontal rudder of the UUV.

[0073] The axial length L corresponding to the mother ship geometric model is extracted, and the axial length is determined as the size feature. For example, the three-dimensional geometric dimensions of the calculation domain are set to (x, y, z) = (6L, 4L, 4L). If the basic dimension is positioned as 0.04L, the total number of grids in the calculation domain is N = (6L / 0.04L)*(4L / 0.04L)*(4L / 0.04L) = 1.5 million. This is only an example and is not intended to limit the scope of protection of this application.

[0074] Then, the computational domain and geometric model are meshed. The computational domain is meshed by an orthogonalized Cartesian network (Eulerian network) method, while the mother ship and UUV are meshed by a surface mesh (Lagrangian mesh) method.

[0075] Finally, the initial conditions of the UUV are configured, including, for example, the initial motion speed, initial position, and initial rudder angle of the UUV.

[0076] In a specific embodiment, during the UUV docking process, interpolation calculation is performed on the mother ship surface grid, the UUV surface grid and the Cartesian grid.

[0077] The formula used for interpolation calculation is shown in formula (1):

[0078]

[0079] Among them, f(x k ) represents x kForce corresponding to the first grid point in the mothership surface grid and / or UUV surface grid, x k represents the first grid point in the mother ship surface grid and / or the UUV surface grid, (i, j) represents any second grid point in the Cartesian grid, F(i, j) represents the corresponding force on the second grid point, ds represents the distance between the first grid point and the nearest second grid point, and h represents the preset size, which is a constant.

[0080] In a specific embodiment, when the mother boat is in a stationary state, f(x k ) represents the force corresponding to the first grid point in the UUV surface grid.

[0081] The following is an example in which the mother ship is in a stationary state and the UUV docks with the mother ship through movement.

[0082] The specific implementation of calculating the surface integral of the wake field information based on the UUV surface grid to obtain the hydrodynamic parameters of the UUV includes:

[0083] Based on the wake field information, the force corresponding to the first grid point in the UUV surface grid is integrated and calculated to obtain the hydrodynamic parameters of the UUV.

[0084] In a specific embodiment, before performing interpolation calculation on the mother ship surface grid and the UUV surface grid and the Cartesian grid, a target grid point is extracted from the Cartesian network, and the target grid point is determined as the second grid point.

[0085] The specific implementation of extracting target grid points in the Cartesian network includes:

[0086] The following extraction operations are performed on each first grid point: the first grid point and multiple second grid points adjacent to the first grid point are obtained to obtain a target vector; an out-of-boundary normal vector corresponding to the target vector is determined; the product of the target vector and the out-of-boundary normal vector is calculated to obtain a judgment value; and the second grid point whose judgment value is greater than zero is used as the target grid point.

[0087] In a specific embodiment, the distance between the first grid point and the nearest second grid point is less than one grid scale.

[0088] Specifically, this application uses two sets of grids to represent the underwater vehicle and the corresponding calculation domain around it. Figure 7 Schematic diagram of two sets of grid interpolation. Figure 7 In the figure, the red line represents the boundary of the computational model (mother ship geometry model and / or UUV geometry model).

[0089] First, we need to determine which Cartesian grids need to be interpolated. Since the two sets of grids are generated independently, some Cartesian grids are located inside the calculation model (in Figure 7(shown by hollow squares in the figure), this part of the grid is meaningless for calculation. Since the hydrodynamic force of the calculation model is obtained by integrating the surface force, there is no need to perform interpolation calculation for this part of the grid. The specific judgment process is as follows:

[0090] Get a first grid point x k , the vector between this point and the adjacent second grid point is λ, x k The normal vector outside the boundary at is X k , and the two are multiplied to obtain the scalar δ. If δ>0, the Cartesian grid is located outside the computational model, otherwise it is located inside.

[0091] After the Cartesian grid points that need to be interpolated are screened, the interpolation calculation is performed using formula (1). In addition, before determining which Cartesian grids need to be interpolated, there is a process of screening the fluid grid points (second grid points) around the solid boundary and determining which surface grid points the force on the Cartesian grid points is interpolated to. For the fluid grid points around the boundary of the computational domain, if the distance between it and the nearest surface grid point is less than one grid scale, it is determined as a fluid grid point that needs to be interpolated.

[0092] In addition, F(i,j) can be obtained through the conventional NS equation.

[0093] In a specific embodiment, the specific implementation of obtaining the motion speed of the UUV at the next moment based on the hydrodynamic parameters includes:

[0094] Based on the hydrodynamic parameters and the pre-created UUV motion equation, the acceleration of the UUV at the current moment is obtained; based on the acceleration and the motion speed at the current moment, the motion speed of the UUV at the next moment is obtained.

[0095] Among them, the UUV motion equation is obtained based on Newton's second law.

[0096] In a specific embodiment, the docking method includes: any one or more of a longitudinal docking method, a vertical docking method and a transverse docking method.

[0097] The specific implementation of controlling and reducing the speed of the component to be controlled corresponding to the docking mode includes:

[0098] When the docking mode is determined to be the longitudinal docking mode, the lateral line speed and the vertical line speed are controlled to be reduced; when the docking mode is determined to be the vertical docking mode, the longitudinal line speed and the lateral line speed are controlled to be reduced; when the docking mode is determined to be the transverse docking mode, the longitudinal line speed and the vertical line speed are controlled to be reduced.

[0099] Specifically, the UUV motion equation is established according to Newton's second law, see formula (2):

[0100] F=ma…………………………(2)

[0101] Among them, F and a both represent matrices, m represents the mass of UUV,

[0102] Among them, F 1 Denotes the longitudinal force, F 2 Indicates the lateral force, F 3 Denotes the vertical force, F 4 Denotes the rolling moment, F 5 Denotes the yaw moment, F 6 is the pitching moment, a 1 is the longitudinal acceleration, a 2 is the lateral acceleration, a 3 is the vertical acceleration, a 4 is the rolling acceleration, a 5 is the yaw acceleration, a 6 Indicates the pitch acceleration.

[0103] After the acceleration is obtained, the speed of movement at the next moment is obtained according to formula (3):

[0104]

[0105] Among them, t represents the timestamp of the current moment, Δt represents the time step, V t Indicates the current speed, V t+Δt Indicates the movement speed at the next moment.

[0106] Below, the longitudinal docking of UUV is taken as an example, that is, the UUV moves forward from the rear of the mother boat to the docking point of the mother boat. This is only an example and is not used to limit the scope of protection of this application.

[0107] According to the movement speed at the next moment, the lateral linear velocity and vertical linear velocity of the UUV are judged. If the lateral linear velocity and vertical linear velocity are not 0, the rudder starts to rotate to offset this part of the speed. Specifically, the rudder rotation can offset the lateral linear acceleration, and the vertical rudder rotation of a certain angle can offset the vertical linear velocity. When the lateral linear velocity and vertical linear velocity are 0 (actually tending to 0), it is determined that the vertical movement of the UUV is suppressed, and the displacement can be calculated based on the displacement calculation formula. See formula (4):

[0108] S t+Δt =V t+Δt ·Δt……………………(4)

[0109] Among them, S t+Δt Represents the motion displacement of UUV at the first moment.

[0110] Among them, the calculations of the other two docking methods are the same as above and will not be elaborated on again.

[0111] Among them, there are actually three directions of displacement (or distance) between the UUV and the mother ship, namely the longitudinal distance, the transverse distance and the vertical distance. In actual docking, distributed docking is adopted, that is, longitudinal docking, transverse docking, and finally vertical docking. There is no requirement for the docking order of the three directions. Space docking is generally not used because of its high risk and low docking success rate.

[0112] The present application solves the problems of large number of grids, low solution accuracy and slow calculation speed in traditional direct numerical simulation methods.

[0113] In terms of computational efficiency:

[0114] 1. Mesh generation efficiency. Two sets of mesh information are pre-written in txt format and pasted into the calculation program to generate the mesh. Since the geometric model and the computational domain mesh are generated independently, the mesh generation efficiency is greatly improved.

[0115] 2. Grid quantity. The grid quantity required for traditional direct numerical simulation is basically 10 7 This is mainly due to local encryption (the UUV operation surface and the area where the UUV moves need to be encrypted). In contrast, since the present invention does not need to adopt a local encryption strategy, the number of grids is 10 6 The calculation requirements can be met.

[0116] 3. Flow field calculation and solution. Traditional solution uses body-fitting grid, and the motion time step must be very small to ensure solution stability. Generally, the time step must be less than 10 -3 s, and in this invention, because two sets of orthogonal grids are used for solving, there is no need to worry about the grid deformation or even tearing caused by too large a time step. The stability of the solution is greatly improved, and the time step can be increased to 0.01s to 0.05s. Taking the total calculation time of 50s as an example, the traditional calculation method requires 50s / 10 -3 s = 5 × 10 4 step, while the present invention only needs 50s / 10 -2 s = 5 × 10 3 step or 50s / 0.05s=1×10 3 This greatly saves calculation time and improves calculation efficiency.

[0117] Calculation accuracy:

[0118] As mentioned above, the traditional calculation method uses body-fitting grids for solving, so the grid must be deformed during the movement process to achieve real-time movement of the UUV. Grid deformation will directly reduce the accuracy of the calculation, and even grid deformation to a certain extent will cause calculation divergence and the calculation cannot be carried out. The calculation method proposed in the present invention uses two sets of independent grids, and realizes the interaction of calculation information through interpolation between the two sets of grids. There is no problem of grid deformation, distortion, etc., and the calculation accuracy can be improved from the traditional second-order accuracy to third-order accuracy.

[0119] It can be seen that the present application realizes the control of safe docking of UUV and mother ship through high-precision and high-efficiency calculation.

[0120] Figure 8 An example of a physical structure diagram of an electronic device is shown in FIG. Figure 8 As shown, the electronic device may include: a processor 801, a communications interface 802, a memory 803 and a communication bus 804, wherein the processor 801, the communications interface 802 and the memory 803 communicate with each other through the communication bus 804. The processor 801 may call the logic instructions in the memory 803 to execute the UUV docking control method based on the direct numerical simulation algorithm.

[0121] In addition, the logic instructions in the above-mentioned memory 803 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0122] On the other hand, the present invention also provides a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium, and the computer program includes program instructions. When the program instructions are executed by a computer, the computer can execute the UUV docking control method based on the direct numerical simulation algorithm provided by the above methods.

[0123] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which is implemented when the computer program is executed by a processor to execute the UUV docking control method based on the direct numerical simulation algorithm provided in the above embodiments.

[0124] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0125] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0126] Finally, it should be noted that the above is only the preferred implementation of the present application, and the present application is not limited to the above embodiments. It is understood that other improvements and changes directly derived or associated by those skilled in the art without departing from the spirit and concept of the present application should be considered to be included in the scope of protection of the present application.

Claims

1. A UUV docking control method based on direct numerical simulation algorithm, characterized in that: The method comprises: Obtain the wake field information corresponding to the mother ship at the current moment, wherein the UUV is in the wake field of the mother ship, and the mother ship surface grid corresponding to the mother ship and the UUV surface grid corresponding to the UUV are within the Cartesian grid corresponding to the calculation domain, and the calculation domain is obtained based on the size characteristics of the mother ship; Performing surface integral calculation on the wake field information based on the UUV surface grid to obtain the hydrodynamic parameters of the UUV, wherein the hydrodynamic parameters include: longitudinal force, lateral force, vertical force, rolling moment, yaw moment and pitch moment; The motion speed of the UUV at the next moment is obtained based on the hydrodynamic parameters, wherein the motion speed includes six component speeds, and the six component speeds include: longitudinal linear speed, lateral linear speed, vertical linear speed, roll angular speed, yaw angular speed and pitch angular speed; Determine the relative position relationship between the UUV and the mothership, and determine the docking mode of the UUV to dock with the mothership at the current moment based on the phase position relationship; The speed of the component to be controlled corresponding to the docking mode is controlled to be reduced, and the motion displacement at the next moment is calculated based on the controlled motion speed, and the step of obtaining the wake field information of the mother ship at the current moment is returned to execute until the UUV completes the docking with the mother ship, wherein the motion displacement includes six component displacements, and the six component displacements include: longitudinal line displacement, lateral line displacement, vertical line displacement, roll angle displacement, yaw angle displacement and pitch angle displacement, and the relative position relationship at the next moment is obtained based on the motion displacement, and there is a preset mapping relationship between the docking mode and the component speed to be controlled.

2. The UUV docking control method based on direct numerical simulation algorithm according to claim 1 is characterized in that: The docking method includes: any one or more of a longitudinal docking method, a vertical docking method and a transverse docking method; Controlling and reducing the speed of the component to be controlled corresponding to the docking mode includes: When it is determined that the docking mode is the longitudinal docking mode, controlling to reduce the lateral linear speed and the vertical linear speed; When it is determined that the docking mode is the vertical docking mode, controlling to reduce the longitudinal line speed and the lateral line speed; When it is determined that the docking mode is the transverse docking mode, the longitudinal line speed and the vertical line speed are controlled to be reduced.

3. The UUV docking control method based on direct numerical simulation algorithm according to claim 1 is characterized in that: The movement speed of the UUV at the next moment is obtained based on the hydrodynamic parameters, including: Based on the hydrodynamic parameters and the pre-created UUV motion equation, the acceleration corresponding to the UUV at the current moment is obtained, wherein the UUV motion equation is obtained based on Newton's second law; Based on the acceleration and the movement speed at the current moment, the movement speed of the UUV at the next moment is obtained.

4. The UUV docking control method based on direct numerical simulation algorithm according to any one of claims 1 to 3, characterized in that: Before obtaining the wake field information corresponding to the mother ship at the current moment, it also includes: Obtaining a UUV geometric model of the UUV and a mothership geometric model of a mothership corresponding to the UUV; Extracting the size characteristics of the mother ship geometric model to obtain a calculation domain corresponding to the UUV geometric model and the mother ship geometric model; The computational domain is meshed based on a Cartesian mesh generation method to obtain the Cartesian mesh, and the UUV geometric model and the mother ship geometric model are meshed based on a surface mesh generation method to obtain a surface mesh, wherein the surface mesh includes: the UUV surface mesh and the mother ship surface mesh.

5. The UUV docking control method based on direct numerical simulation algorithm according to any one of claims 1 to 3, characterized in that: The method further comprises: During the UUV docking process, interpolation calculation is performed on the mother ship surface grid, the UUV surface grid and the Cartesian grid; The formulas used for interpolation calculation include: Among them, f(x k ) represents x k Force corresponding to the first grid point in the mothership surface grid and / or UUV surface grid, x k represents the first grid point in the mother ship surface grid and / or the UUV surface grid, (i, j) represents any second grid point in the Cartesian grid, F(i, j) represents the corresponding force on the second grid point, ds represents the distance between the first grid point and the nearest second grid point, and h represents the preset size, which is a constant.

6. The UUV docking control method based on direct numerical simulation algorithm according to claim 5 is characterized in that: When the mother boat is at rest, f(x k ) represents the force corresponding to the first grid point in the UUV surface grid; The wake field information is surface-integrated based on the UUV surface grid to obtain the hydrodynamic parameters of the UUV, including: Based on the wake field information, the force corresponding to the first grid point in the UUV surface grid is integrated and calculated to obtain the hydrodynamic parameters of the UUV.

7. The UUV docking control method based on direct numerical simulation algorithm according to claim 5 is characterized in that: Before performing interpolation calculation on the mother ship surface grid, the UUV surface grid and the Cartesian grid, the method further includes: A target grid point is extracted from the Cartesian network, and the target grid point is determined as the second grid point. Extracting target grid points from the Cartesian network includes: For each first grid point, perform the following extraction operation: Acquire the first grid point and a plurality of second grid points adjacent to the first grid point to obtain a target vector; Determining an out-of-bounds normal vector corresponding to the target vector; Calculate the product of the target vector and the normal vector outside the boundary to obtain a determination value; The second grid point whose determination value is greater than zero is used as the target grid point.

8. The UUV docking control method based on direct numerical simulation algorithm according to claim 5 is characterized in that: The distance between the first grid point and the nearest second grid point is less than one grid scale.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the steps of the UUV docking control method based on the direct numerical simulation algorithm as described in any one of claims 1 to 8 are implemented.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the UUV docking control method based on the direct numerical simulation algorithm as described in any one of claims 1 to 8 are implemented.

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