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

Abstract

The application discloses a UUV docking control method and device based on a direct numerical simulation algorithm and a medium, relates to the underwater vehicle control technical field, and comprises the following steps: acquiring tail flow field information corresponding to a mother ship at a current moment; performing area integral calculation on the tail flow field information based on a UUV surface grid to obtain hydrodynamic parameters of the UUV; obtaining the motion speed of the UUV at the next moment based on the hydrodynamic parameters; determining a docking mode of the UUV docking the mother ship at the current moment; controlling the speed of a to-be-controlled component corresponding to the docking mode to be reduced, calculating the motion displacement at the next moment based on the controlled motion speed, and returning to the step of acquiring the tail flow field information of the mother ship at the current moment until the UUV and the mother ship are docked. The application is used to solve the problems of low precision and low efficiency in the UUV docking process control in the prior art, and realizes fast and accurate docking control of the UUV and the mother ship.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of underwater vehicle control, and particularly relates to a UUV docking control method and device based on a direct numerical simulation algorithm and a medium. BACKGROUND

[0002] At present, underwater vehicles (UUVs) have wide applications in many fields such as military ocean technology, ocean scientific and technological investigation, seabed exploration, pipeline maintenance, and seabed salvage. In the operation of the UUV, the UUV generally uses self-contained energy for operation, and the working time and navigation distance are limited, so the UUV needs to be recovered and docked for energy replenishment.

[0003] The UUV docking process is difficult and costly to test, and at present, the simulation technology is used to evaluate the UUV docking process. The simulation analysis of the UUV docking process mainly includes two types: mathematical model simulation and direct numerical simulation. The former mainly uses linear theory assumption to simulate the motion process by means of mathematical model. Although the calculation amount of this method is small, the fluid viscosity is ignored, which leads to 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 the UUV and the mother ship. Although the calculation accuracy of this method is high, because the body-fitted grid is used, the number of grids is large, so a huge computing resource needs to be configured, the overall computing resource consumption is large, the calculation efficiency is low, and the grid must be deformed to realize the motion of the UUV in the docking process, but the grid deformation to a certain extent will lead to calculation divergence and cannot continue to calculate. SUMMARY

[0004] To solve the problems of low accuracy and low efficiency in the UUV docking process control in the prior art, the present application provides a UUV docking control method and device based on a direct numerical simulation algorithm to realize fast and accurate docking control of the UUV and the mother ship.

[0005] The present application provides a UUV docking control method based on a direct numerical simulation algorithm, which comprises the following steps:

[0006] obtaining tail flow field information corresponding to the mother ship at the current time, wherein the UUV is in the tail flow 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;

[0007] performing area integral calculation on the tail flow 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, roll moment, yaw moment, and pitch moment;

[0008] obtaining a motion velocity of the UUV at a next time based on the hydrodynamic parameter, wherein the motion velocity comprises six component velocities, and the six component velocities comprise a longitudinal linear velocity, a lateral linear velocity, a vertical linear velocity, a roll angular velocity, a yaw angular velocity and a pitch angular velocity;

[0009] determining a relative position relationship between the UUV and the mother ship, and determining a docking mode of the UUV docking the mother ship at the current time based on the relative position relationship;

[0010] controlling a to-be-controlled component velocity corresponding to the docking mode, and calculating a motion displacement at the next time based on the controlled motion velocity, and returning to the step of obtaining the wake field information of the mother ship at the current time until the UUV and the mother ship complete docking, wherein the motion displacement comprises six component displacements, and the six component displacements comprise a longitudinal linear displacement, a lateral linear displacement, a vertical linear displacement, a roll angular displacement, a yaw angular displacement and a pitch angular displacement, a relative position relationship at the next time is obtained based on the motion displacement, and the docking mode and the to-be-controlled component velocity have a preset mapping relationship.

[0011] According to the UUV docking control method based on the direct numerical simulation algorithm provided in the embodiments of the present application, the docking mode comprises any one or more of a longitudinal docking mode, a vertical docking mode and a transverse docking mode.

[0012] controlling the to-be-controlled component velocity corresponding to the docking mode, comprises:

[0013] in a case where the docking mode is determined as the longitudinal docking mode, controlling the lateral linear velocity and the vertical linear velocity to be reduced;

[0014] in a case where the docking mode is determined as the vertical docking mode, controlling the longitudinal linear velocity and the lateral linear velocity to be reduced;

[0015] in a case where the docking mode is determined as the transverse docking mode, controlling the longitudinal linear velocity and the vertical linear velocity to be reduced.

[0016] According to the UUV docking control method based on the direct numerical simulation algorithm provided in the embodiments of the present application, obtaining a motion velocity of the UUV at a next time based on the hydrodynamic parameter, comprises:

[0017] obtaining an acceleration corresponding to the UUV at the current time based on the hydrodynamic parameter and a pre-created UUV motion equation, wherein the UUV motion equation is obtained based on Newton's second law;

[0018] Based on the acceleration and the current velocity, the velocity of the UUV at the next moment is obtained. According to the UUV docking control method based on direct numerical simulation algorithm provided in this application embodiment, before obtaining the wake field information corresponding to the mother vessel at the current moment, the method further includes:

[0019] Obtain the UUV geometric model and the corresponding mothership geometric model;

[0020] Extract the dimensional features of the mothership geometric model to obtain the computational domain corresponding to the UUV geometric model and the mothership geometric model;

[0021] The computational domain is meshed using a Cartesian mesh generation method to obtain the Cartesian mesh, and the UUV geometric model and the mothership geometric model are meshed using a surface mesh generation method to obtain surface meshes, wherein the surface meshes include the UUV surface mesh and the mothership surface mesh.

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

[0023] During the UUV docking process, interpolation calculations are performed on the mother ship surface mesh, the UUV surface mesh, and the Cartesian mesh;

[0024] The formulas used for interpolation calculations include:

[0025]

[0026] Where, f(x) k ) represents x k The force corresponding to the first grid point in the mothership surface mesh and / or UUV surface mesh, x k Let (i,j) represent the first grid point in the mothership surface grid and / or UUV surface grid, (i,j) represent any second grid point in the Cartesian grid, F(i,j) represent the force corresponding to the second grid point, ds represent 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 embodiments of this application, when the mother vessel is stationary, f(x) k ) represents the force corresponding to the first grid point in the UUV surface mesh;

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

[0029] Integrate and calculate the force corresponding to the first grid point in the UUV surface grid based on the wake field information, to obtain the hydrodynamic parameters of the UUV.

[0030] The UUV docking control method based on the direct numerical simulation algorithm provided in the embodiments of the present application further includes the following before interpolation calculation is performed on the mother ship surface grid and the UUV surface grid and the Cartesian grid:

[0031] Extract a target grid point from the Cartesian network, and determine the target grid point as the second grid point.

[0032] The target grid point is extracted from the Cartesian network, including:

[0033] The following extraction operation is performed on each first grid point:

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

[0035] Determine a boundary outer normal vector corresponding to the target vector;

[0036] Calculate the product of the target vector and the boundary outer normal vector, to obtain a decision value;

[0037] The second grid point with a decision value greater than zero is taken as the target grid point.

[0038] The embodiments of the present application further provide an electronic device including a memory, a processor, and a computer program stored on the memory and executable on the processor, and the processor implements the steps of the UUV docking control method based on the direct numerical simulation algorithm according to any one of the above when executing the program.

[0039] The embodiments of the present application further provide a non-transitory computer readable storage medium having a computer program stored thereon, and the computer program is executable on a processor to implement the steps of the UUV docking control method based on the direct numerical simulation algorithm according to any one of the above.

[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 the 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, which guarantees the calculation precision, reduces the calculation resource consumption, and improves the calculation speed.

[0041] And, the wake field information is calculated based on the UUV surface grid by area integration to obtain the hydrodynamic parameters of the UUV; the movement 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 the mother ship at the current moment is determined; the to-be-controlled component speed corresponding to the docking mode is controlled to reduce, and the movement displacement at the next moment is calculated based on the controlled movement 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 and the mother ship complete docking, and through the movement parameters (movement speed and movement displacement) of the UUV and the relative position relationship between the UUV and the mother ship, the UUV is controlled in real time to realize the safe docking of the UUV and the mother ship. BRIEF DESCRIPTION OF DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0043] Figure 1 is a flowchart of the UUV docking control method based on the direct numerical simulation algorithm provided by the embodiments of the present application;

[0044] Figure 2 is a calculation domain schematic diagram provided by the embodiments of the present application;

[0045] Figure 3 is a surface grid schematic diagram provided by the embodiments of the present application;

[0046] Figure 4 is a relative position schematic diagram provided by the embodiments of the present application;

[0047] Figure 5 is a mother ship geometric model provided by the embodiments of the present application;

[0048] Figure 6 is a UUV geometric model provided by the embodiments of the present application;

[0049] Figure 7 is a two-grid interpolation schematic diagram provided by the embodiments of the present application;

[0050] Figure 8 is a structural schematic diagram of an electronic device provided by the embodiments of the present application. DETAILED DESCRIPTION

[0051] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0052] The embodiments of the present application provide a UUV docking control method based on a direct numerical simulation algorithm. The method can be applied to an intelligent terminal, can also be applied to a server, and can also be applied to a controller of an underwater vehicle. The present application takes the case that the method is applied to the controller of the underwater vehicle as an example for description, and some other descriptions in the embodiments are for example description and do not limit the protection scope of the present application. The specific implementation of the method is as shown in Figure 1

[0053] Step 101, tail flow field information corresponding to a mother ship at a current time is obtained.

[0054] The tail flow field information includes tail flow field velocity and tail flow field pressure.

[0055] The UUV is in the tail flow field of the mother ship, the mother ship face grid corresponding to the mother ship and the UUV face 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] The Cartesian grid corresponding to the calculation domain is as shown in the following figure: Figure 2 The Cartesian grid corresponding to the calculation domain is as shown in the following figure: Figure 3 The face grid is as shown in the following figure:

[0057] Step 102, the tail flow field information is subjected to area integral calculation based on the UUV face grid, to obtain a hydrodynamic parameter of the UUV.

[0058] The hydrodynamic parameter includes longitudinal force, lateral force, vertical force, roll moment, yaw moment and pitch moment.

[0059] Step 103, a motion speed of the UUV at a next time is obtained based on the hydrodynamic parameter.

[0060] 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.

[0061] Step 104, a relative position relationship between the UUV and the mother ship is determined, and a docking mode of the UUV docking the mother ship at the current time is determined based on the relative position relationship. ​

[0062] In step 105, the speed of the to-be-controlled component corresponding to the docking mode is controlled to be reduced, the motion displacement at the next moment is calculated based on the controlled motion speed, and the step of acquiring the wake field information of the mother ship at the current moment is executed again until the UUV and the mother ship complete docking.

[0063] The motion displacement includes six component displacements, and the six component displacements include a longitudinal linear displacement, a lateral linear displacement, a vertical linear displacement, a roll angle displacement, a yaw angle displacement, and a pitch angle displacement. The relative position relationship at the next moment is obtained based on the motion displacement, and the docking mode and the to-be-controlled component speed have a preset mapping relationship.

[0064] The UUV docking control method based on the direct numerical simulation algorithm provided in the embodiments of the present application performs information interaction through interpolation between two sets of networks (a mother ship surface grid corresponding to the mother ship and a UUV surface grid corresponding to the UUV in a corresponding Cartesian grid in the calculation domain), and there is no problem of grid deformation and distortion, which ensures the calculation accuracy, reduces the amount of consumed calculation resources, and improves the calculation speed.

[0065] The wake field information is calculated based on 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, the docking mode of the UUV docking the mother ship at the current moment is determined based on the relative position relationship, the speed of the to-be-controlled component corresponding to the docking mode is controlled to be reduced, the motion displacement at the next moment is calculated based on the controlled motion speed, and the step of acquiring the wake field information of the mother ship at the current moment is executed again until the UUV and the mother ship complete docking. The motion parameters (motion speed and motion displacement) of the UUV and the relative position relationship between the UUV and the mother ship are used to control the UUV in real time to realize safe docking of the UUV and the mother ship.

[0066] The relative position relationship between the UUV and the mother ship is determined based on the relative position relationship. Figure 4 Taking longitudinal docking as an example, the relative position relationship is shown in the figure, in which S represents the distance between the UUV and the mother ship.

[0067] In one specific embodiment, before acquiring the wake field information of the mother ship corresponding to 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 acquired; the size features of the mother ship geometric model are extracted to obtain a calculation domain corresponding to the UUV geometric model and the mother ship geometric model; the calculation domain is meshed based on a Cartesian grid generation method to obtain a Cartesian grid, and the UUV geometric model and the mother ship geometric model are meshed based on a surface grid generation method to obtain a surface grid.

[0068] The surface grid includes a UUV surface grid and a mother ship surface grid.

[0069] Specifically, the lines or the value table of the UUV and the mother ship are used to make physical modeling to obtain the UUV geometric model and the mother ship geometric model. The UUV geometric model includes the main body, the control surface and the propeller of the UUV, and the mother ship geometric model includes the main body and the control surface of the mother ship. The modeling software can be used to realize the above.

[0070] The mother ship geometric model is shown in Figure 5 , and the UUV geometric model is shown in Figure 6 .

[0071] In Figure 5 , 1 is the main body of the mother ship, 2 is the mother ship shell, 3-1 is one rudder of the mother ship shell, 3-2 is another rudder of the mother ship shell, 4-1 is the upper vertical rudder of the mother ship, 4-2 is the lower vertical rudder of the mother ship, 4-3 is the left horizontal rudder of the mother ship, and 4-4 is the right horizontal rudder of the mother ship.

[0072] In Figure 6 , 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 a size feature. For example, the three-dimensional geometric size of the calculation domain is set as (x, y, z) = (6L, 4L, 4L). If the basic size is set as 0.04L, the total number of grids of the calculation domain is N = (6L / 0.04L)*(4L / 0.04L)*(4L / 0.04L) = 1.5 million. Herein, the example is only used to illustrate and does not limit the protection scope of the present application.

[0074] Further, the grid generation is performed on the calculation domain and the geometric model. The orthogonal Cartesian network (Euler network) generation method is used for the grid generation of the calculation domain, and the surface grid (Lagrangian grid) generation method is used for the grid generation of the mother ship and the UUV.

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

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

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

[0078]

[0079] Wherein, f(x k ) represents x kThe force corresponding to the first grid point in the mothership surface mesh and / or UUV surface mesh, x k Let (i,j) represent the first grid point in the mothership surface grid and / or UUV surface grid, (i,j) represent any second grid point in the Cartesian grid, F(i,j) represent the force corresponding to the second grid point, ds represent 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 one specific embodiment, when the mothership is stationary, f(x) k ) represents the force corresponding to the first grid point in the UUV surface mesh.

[0081] The following example illustrates the process of the UUV docking with the mother vessel while the mother vessel is stationary, through movement.

[0082] The specific implementation of obtaining the hydrodynamic parameters of the UUV by performing area integral calculation based on the wake field information using the UUV surface mesh includes:

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

[0084] In one specific embodiment, before performing interpolation calculations between the mothership surface mesh and the UUV surface mesh and the Cartesian mesh, target mesh points are extracted from the Cartesian network and the target mesh points are determined as second mesh points.

[0085] The specific implementation of extracting target grid points from a Cartesian network includes:

[0086] For each first grid point, perform the following extraction operations: obtain the first grid point and multiple second grid points adjacent to the first grid point to obtain the target vector; determine the boundary out-of-bounds normal vector corresponding to the target vector; calculate the product of the target vector and the boundary out-of-bounds normal vector to obtain the judgment value; and take the second grid points with a judgment value greater than zero as the target grid points.

[0087] In one 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 employs two sets of meshes to characterize the underwater vehicle and its corresponding computational domain, respectively. Through... Figure 7 This diagram illustrates two sets of grid interpolation methods. Figure 7 In the diagram, the red lines represent the boundaries of the computational model (the mothership geometry model and / or the UUV geometry model).

[0089] First, it's necessary to determine which Cartesian meshes require interpolation. Since the two mesh sets are generated independently, some Cartesian meshes reside within the computational model (in...). Figure 7(Illustrated by hollow cubes), this part of the mesh is meaningless for calculation. Since the hydrodynamics of the computational model are obtained from the integral of the surface forces, no interpolation calculation is needed for this part of the mesh. The specific judgment process is as follows:

[0090] Obtain a certain first grid point x k The vector between this point and its adjacent second grid point is λ, x k The boundary outward normal vector at point X is k Multiplying the two yields a scalar δ. If δ > 0, the Cartesian grid lies outside the computational model; otherwise, it lies inside.

[0091] After selecting the Cartesian grid points that require interpolation, interpolation calculations are performed using formula (1). Furthermore, before determining which Cartesian grid points require interpolation, there is a process of selecting the fluid grid points (second grid points) around the solid boundary, and determining which surface grid points the forces on the Cartesian grid points will be interpolated to. For fluid grid points around the computational domain boundary, if the distance between it and the nearest surface grid point is less than one grid scale, it is identified as a fluid grid point requiring interpolation.

[0092] In addition, F(i,j) can be obtained through the conventional Navier-Stokes equations.

[0093] In one specific embodiment, the specific implementation of obtaining the UUV's velocity at the next moment based on hydrodynamic parameters includes:

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

[0095] The equations of motion for UUVs are derived from Newton's second law.

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

[0097] The specific implementation of controlling the reduction of the velocity of the component to be controlled corresponding to the docking method includes:

[0098] When the docking method is determined to be longitudinal docking, control and reduce the lateral and vertical linear velocities; when the docking method is determined to be vertical docking, control and reduce the longitudinal and lateral linear velocities; when the docking method is determined to be transverse docking, control and reduce the longitudinal and vertical linear velocities.

[0099] Specifically, the equations of motion for the UUV are established based on Newton's second law, see formula (2):

[0100] F = ma … … (2)

[0101] where F and a are matrices, and m is the mass of the UUV,

[0102] where F1 is the longitudinal force, F2 is the lateral force, F3 is the vertical force, F4 is the roll moment, F5 is the yaw moment, F6 is the pitch moment, a1 is the longitudinal acceleration, a2 is the lateral acceleration, a3 is the vertical acceleration, a4 is the roll acceleration, a5 is the yaw acceleration, and a6 is the pitch acceleration.

[0103] After obtaining the acceleration, the motion velocity at the next time is obtained according to formula (3):

[0104]

[0105] where t is the time stamp of the current time, Δt is the time step, V t is the motion velocity at the current time, V t+Δt is the motion velocity at the next time.

[0106] Next, taking the UUV longitudinal docking as an example, i.e., the UUV moves from the rear of the mother ship to the docking place of the mother ship, which is only used for illustration and does not limit the protection scope of the present application.

[0107] According to the motion velocity at the next time, the lateral linear velocity and the vertical linear velocity of the UUV are judged. If the lateral linear velocity and the vertical linear velocity are not 0, the rudder starts to rotate to offset the part of the velocity. Specifically, the rudder rotation can offset the lateral linear acceleration, and the vertical rudder rotates a certain angle to offset the vertical linear velocity. When the lateral linear velocity and the vertical linear velocity are 0 (it can be close to 0), it is determined that the vertical motion 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] where S t+Δt is the motion displacement of the UUV at the first time.

[0110] where the calculation of the other two docking modes is the same as above, and will not be described.

[0111] Among them, there are actually three directions of displacement (or distance) between the UUV and the mother ship, namely longitudinal distance, transverse distance and vertical distance. When actually docking, distributed docking is adopted, that is, longitudinal docking is carried out first, then transverse docking, and finally vertical docking. The order of three-direction docking has no requirement. Generally, spatial docking is not adopted, and the reason is that the risk is high and the docking success rate is low.

[0112] The application solves the problems of large number of grids, low solving precision and slow calculation speed of the traditional direct numerical simulation method.

[0113] In terms of calculation efficiency:

[0114] 1. In terms of grid generation efficiency, two sets of grid information are pre-written in txt text form and pasted into the calculation program to generate the grid. Since the geometric model and the calculation domain grid are generated independently, the grid generation efficiency is greatly improved.

[0115] 2. In terms of the number of grids, the traditional direct numerical simulation requires a grid of the order of 10 7 , which is mainly due to local encryption (UUV operation surface, UUV movement area needs to be encrypted). In comparison, since the local encryption strategy is not used in the application, the number of grids of the order of 10 6 can meet the calculation requirements.

[0116] 3. In terms of flow field calculation and solving, the traditional solving method adopts body-fitted grid, and the time step must be very small to ensure the stability of the solving, generally the time step must be less than 10 -3 s, while in the application, since two sets of orthogonal grids are used for solving, there is no worry about the grid distortion or even tearing caused by too large time step, the stability of the solving is greatly increased, and the time step can be increased to 0.01s-0.05s. Taking the total calculation time of 50s as an example, the traditional calculation method needs 50s / 10 -3 s=5x10 4 steps, while the application only needs 50s / 10 -2 s=5x10 3 steps or 50s / 0.05s=1x10 3 steps. Greatly saving the calculation time and improving the calculation efficiency.

[0117] In terms of calculation precision:

[0118] As described above, the traditional calculation method adopts the body-fitted grid to solve, and the grid must be deformed to realize the real-time movement of the UUV during the movement. The grid deformation directly reduces the calculation accuracy, and even the grid deformation to a certain extent will lead to the calculation divergence, and the calculation cannot continue. The calculation method provided in the application adopts two independent grids, and the calculation information is exchanged through the interpolation between the two grids, and there is no problem of grid deformation, distortion and the like, and the calculation accuracy can be improved from the traditional second-order accuracy to third-order accuracy.

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

[0120] Figure 8 An example of a schematic diagram of a physical structure of an electronic device is shown in Figure 8 As shown, the electronic device can include a processor 801, a communications interface 802, a memory 803 and a communications bus 804, wherein the processor 801, the communications interface 802 and the memory 803 complete mutual communication through the communications bus 804. The processor 801 can call the logical instructions in the memory 803 to execute the UUV docking control method based on the direct numerical simulation algorithm.

[0121] In addition, the logical instructions in the memory 803 described above can be realized in the form of a software function unit and sold or used as an independent product, and can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the application essentially or the part that contributes to the prior art or part of the technical solutions can be embodied in the form of a software product, and the computer software product stored in a storage medium includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in the embodiments of the application. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk and various program code storage media.

[0122] On the other hand, the application 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-mentioned methods.

[0123] In yet another aspect, the present application also provides a non-transitory computer readable storage medium having stored thereon a computer program, which, when executed by a processor, implements the UUV docking control method based on the direct numerical simulation algorithm provided by each of the above embodiments.

[0124] The apparatus embodiments described above are merely illustrative, wherein the units described as separate components can or can not be physically separate, and the components displayed as units can or can not be physical units, i.e., can be located in one place, or can be distributed to multiple network units. Part or all of the modules can be selected to achieve the purpose of the embodiment scheme according to actual needs. Those skilled in the art can understand and implement without creative labor.

[0125] From the above description of the embodiments, those skilled in the art can clearly understand that the embodiments can be realized by means of software plus the necessary general hardware platform, and of course can also be realized by hardware. Based on such understanding, the above technical solutions can be embodied in the form of a software product, which can be stored in a computer readable storage medium, such as a ROM / RAM, a magnetic disk, an optical disk, etc., and includes a plurality of instructions to make a computer device (which can be a personal computer, a server, or a network device, etc.) execute the methods described in each embodiment or some parts of the embodiments.

[0126] Finally, it should be noted that: the above description is only the preferred embodiment of the present application, and the present application is not limited to the above embodiments. It can be understood that other improvements and changes directly derived or thought 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 protection scope of the present application.

Claims

1. A UUV docking control method based on a direct numerical simulation algorithm, characterized in that, The method comprises: obtaining wake field information corresponding to the mother ship at the current time, wherein the UUV is in the wake field of the mother ship, the mother ship face grid corresponding to the mother ship and the UUV face 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; performing area integral calculation on the wake field information based on the UUV face grid to obtain the hydrodynamic parameters of the UUV, wherein the hydrodynamic parameters include longitudinal force, lateral force, vertical force, roll moment, yaw moment and pitch moment; obtaining the motion speed of the UUV at the next time 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; determining the relative position relationship between the UUV and the mother ship, and determining the docking mode of the UUV docking the mother ship at the current time based on the relative position relationship; controlling to reduce the to-be-controlled component speed corresponding to the docking mode, and calculating the motion displacement at the next time based on the controlled motion speed, and returning to perform the step of obtaining the wake field information of the mother ship at the current time until the UUV and the mother ship complete docking, wherein the motion displacement includes six component displacements, and the six component displacements include longitudinal linear displacement, lateral linear displacement, vertical linear displacement, roll angular displacement, yaw angular displacement and pitch angular displacement, the relative position relationship at the next time is obtained based on the motion displacement, and the docking mode and the to-be-controlled component speed have a preset mapping relationship; wherein, during the docking process of the UUV, interpolation calculation is performed on the mother ship face grid and the UUV face grid and the Cartesian grid; wherein, the formula for interpolation calculation comprises: ； wherein, represents represents the force corresponding to the first grid point in the mother vessel surface grid and / or the UUV surface grid, represents the first grid point in the mother vessel surface grid and / or the UUV surface grid, represents any second grid point in the Cartesian grid, represents the force corresponding to the second grid point, represents the distance between the first grid point and the nearest second grid point, represents the preset size, which is a constant; wherein, before the interpolation calculation is performed on the mother ship face grid and the UUV face grid and the Cartesian grid, it further comprises: extracting a target grid point from the Cartesian network, and determining the target grid point as the second grid point; the target grid point is extracted from the Cartesian network, comprising: performing the following extraction operation on each first grid point: obtaining the first grid point and a plurality of second grid points adjacent to the first grid point to obtain a target vector; determining a boundary outer normal vector corresponding to the target vector; calculating the product of the target vector and the boundary outer normal vector to obtain a judgment value; the second grid point with a judgment value greater than zero is taken as the target grid point.

2. The UUV docking control method based on a direct numerical simulation algorithm of claim 1, wherein, The docking mode includes any one or more of the longitudinal docking mode, the vertical docking mode and the transverse docking mode; controlling to reduce the to-be-controlled component speed corresponding to the docking mode comprises: in a case where it is determined that the docking mode is the longitudinal docking mode, controlling to reduce the lateral linear speed and the vertical linear speed; in a case where it is determined that the docking mode is the vertical docking mode, controlling to reduce the longitudinal linear speed and the lateral linear speed; in a case where it is determined that the docking mode is the transverse docking mode, controlling to reduce the longitudinal linear speed and the vertical linear speed.

3. The UUV docking control method based on a direct numerical simulation algorithm of claim 1, wherein, obtaining a motion velocity of the UUV at a next time based on the hydrodynamic parameter, comprising: obtaining an acceleration of the UUV at the current time based on the hydrodynamic parameter and a pre-created UUV motion equation, wherein the UUV motion equation is obtained based on Newton's second law; obtaining the motion velocity of the UUV at the next time based on the acceleration and the motion velocity at the current time.

4. The UUV docking control method based on a direct numerical simulation algorithm according to any one of claims 1-3, characterized in that, Before obtaining the wake field information of the mother ship at the current time, further comprising: obtaining a UUV geometric model of the UUV and a mother ship geometric model of the mother ship corresponding to the UUV; extracting a size feature of the mother ship geometric model to obtain a calculation domain corresponding to the UUV geometric model and the mother ship geometric model; generating a Cartesian grid based on a Cartesian grid generation method for the calculation domain to obtain the Cartesian grid, and generating a surface grid based on a surface grid generation method for the UUV geometric model and the mother ship geometric model to obtain the surface grid, wherein the surface grid comprises the UUV surface grid and the mother ship surface grid.

5. The UUV docking control method based on a direct numerical simulation algorithm of claim 1, wherein, In the case where the mother ship is in a stationary state, represents the force corresponding to the first grid point in the UUV surface grid; performing an area integral calculation on the wake field information based on the UUV surface grid to obtain the hydrodynamic parameter of the UUV, comprising: performing an integral calculation on a force corresponding to a first grid point in the UUV surface grid based on the wake field information to obtain the hydrodynamic parameter of the UUV.

6. The UUV docking control method based on a direct numerical simulation algorithm of claim 1, wherein, The distance between the first grid point and the nearest second grid point is less than a grid scale.

7. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor executes the program to implement the steps of the UUV docking control method based on the direct numerical simulation algorithm according to any one of claims 1 to 6.

8. A non-transitory computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to implement the steps of the UUV docking control method based on the direct numerical simulation algorithm according to any one of claims 1 to 6.

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