An Optimization Method for the Detection AUV Model of a Water Conveyance Tunnel

Abstract

The present invention proposes an optimization method for the inspection AUV model of a water conveyance tunnel. An applicable coordinate system is established according to the working environment, and then the six-degree-of-freedom motion equation of the AUV is established from the perspectives of rigid body and fluid force, and decomposed into horizontal and vertical plane motions to establish kinematic and dynamic models. The tunnel inspection AUV model is simplified. Finally, from the perspective of a new type of wing plate, computational fluid dynamics analysis is carried out according to the working conditions of the water conveyance tunnel, laying a foundation for energy consumption modeling, energy-saving operation planning, and energy-saving control.

Description

Technical Field

[0001] The present invention belongs to the technical field of water conveyance tunnel detection, and specifically relates to an optimization method for an AUV model for water conveyance tunnel detection. Background Art

[0002] China has a rich total amount of water resources. However, from the perspectives of time and space, the distribution of water resources is very uneven. Therefore, in order to achieve the optimal allocation of water resources, China has widely built water conveyance tunnels such as irrigation tunnels, water supply tunnels, flood discharge tunnels, and water diversion tunnels. In order to ensure the safe operation of the tunnels, it is necessary to conduct regular inspection, maintenance, and safety evaluation of the tunnels. At present, manual general inspection and inspection require emptying the tunnel to stop water conveyance, consuming a large amount of manpower, material resources, and financial resources; using an ROV (Remotely Operated Vehicle) for detection cannot achieve long-distance detection. With the development of science and technology, using an unmanned and cableless AUV for water conveyance tunnel detection has become one of the research hotspots.

[0003] Compared with the traditional manual detection method, using an AUV for water conveyance tunnel detection has the advantages of low cost, convenient use, high detection accuracy, not affecting the operation of the tunnel, and being able to conduct long-time and large-scale detection. However, from the working environment and its own motion characteristics of the AUV for tunnel detection, it is very difficult to establish its accurate mathematical model. Even if some researchers can design a sufficiently accurate mathematical model, this model is often too complex and not suitable for control system design. Summary of the Invention

[0004] In view of the many problems of the AUV model for water conveyance tunnel detection, the present invention proposes an optimization method for the AUV model for water conveyance tunnel detection, establishes the kinematic model and dynamic model of the AUV for tunnel detection, simplifies the mathematical model of the AUV for tunnel detection, and conducts a force analysis of the AUV for tunnel detection.

[0005] The present invention is realized through the following technical solutions:

[0006] An optimization method for an AUV model for water conveyance tunnel detection, the method specifically includes the following steps:

[0007] Step 1, define the motion coordinate system and the geodetic coordinate system of the AUV for tunnel detection according to the working environment, and obtain the conversion relationship between the coordinate systems according to the motion parameters of the AUV for tunnel detection;

[0008] Step 2, establish the kinematic model and dynamic model of the AUV for tunnel detection according to the data in Step 1;

[0009] Step 3, simplify the mathematical model of the AUV for tunnel detection according to the kinematic model and dynamic model in Step 2, and conduct a force analysis of the AUV for tunnel detection;

[0010] Step 4: Use SOLIDWORKS 3D modeling software to establish the tunnel inspection AUV model, check the validity of the model, and repair it if there are any problems to complete the optimization of the tunnel inspection AUV model.

[0011] Furthermore, in Step 1, the tunnel inspection AUV is regarded as a rigid body, and its motion is decomposed into a set of spatial motions of its center of buoyancy and a set of rotations about its center of buoyancy.

[0012] Two coordinate systems determined by the right-hand rule system: the moving coordinate system is B-xyz, which is fixedly connected to the tunnel inspection AUV and moves with the tunnel inspection AUV; the earth coordinate system is E-ξηζ, which is fixedly connected to the earth.

[0013] Earth coordinate system E-ξηζ: The origin E is selected as a fixed point on the earth. The Eξ axis is located in the horizontal plane, and the main heading of the tunnel inspection AUV is the positive direction; the Eζ axis is perpendicular to the ξEη coordinate plane, and the positive direction points to the center of the earth. The Eη axis is located in the horizontal plane where the Eξ axis is located, and the Eξ axis is rotated 90° clockwise according to the right-hand rule.

[0014] The moving coordinate system is B-xyz: Set the center of buoyancy of the tunnel inspection AUV as the origin B. Then the Bx axis is located on the intersection line of the waterline plane passing through point B and the longitudinal middle section, and points in the forward movement direction of the tunnel inspection AUV. The By axis is located on the intersection line of the cross-section passing through point B and the waterline plane. The By axis is perpendicular to the Bx axis and points from the left wing direction to the right wing direction. The Bz axis is located on the intersection line of the cross-section passing through point B and the longitudinal middle section, and points downward of the tunnel inspection AUV. The positive direction is specified according to the right-hand system.

[0015] Since the moving coordinate system is fixedly connected to the AUV body of the tunnel inspection, the motion performed by the tunnel inspection AUV can be transformed into the motion relationship of the moving coordinate system relative to the earth coordinate system.

[0016] The position of the tunnel inspection AUV is represented by the coordinates (ξ B , η B , ζ B ) of the origin of the moving coordinate system in the earth coordinate system; the attitude of the tunnel inspection AUV can be represented by three angles for the conversion between the moving coordinate system and the earth coordinate system: roll angle , pitch angle θ, and yaw angle ψ. The representation method is as follows:

[0017] Roll angle : The projection of the angle formed by the Eη axis and the By axis in the ηEζ plane, and the positive direction is the clockwise rotation of the Eη axis to the By axis.

[0018] Pitch angle θ: The projection of the angle formed by the Eξ axis and the Bx axis in the vertical plane, and the positive direction is the counterclockwise rotation of the Eξ axis to the Bx axis.

[0019] Yaw angle ψ: The projection of the angle formed by the Eξ axis and the Bx axis on the horizontal plane, with the positive direction being the clockwise rotation of the Eξ axis to the Bx axis;

[0020] According to the roll angle Pitch angle θ, yaw angle ψ, the two coordinate systems are transformed by three rotations;

[0021] First, rotate by ψ around the Eζ axis, Eξ → Bx1, Eη → By1, then:

[0022]

[0023] Then rotate by θ around the By1 axis, Bx1 → Bx, Eζ → Bz1, then:

[0024]

[0025] Finally, rotate around the Bx axis By1 → By, Bz1 → Bz, then:

[0026]

[0027] Combining and superimposing equations (1) to (3), it can be obtained that

[0028]

[0029] Furthermore, in step 2,

[0030] The method for establishing the kinematic model is as follows: The coordinates of the tunnel detection AUV in the geodetic coordinate system are (ξ B , η B , ζ B ), and its speed is set as The speeds of the tunnel detection AUV in the three directions in the moving coordinate system are (u, v, w). Then the conversion relationship between the speeds of the two coordinate systems can be expressed as:

[0031]

[0032] The attitude of the tunnel detection AUV in the geodetic coordinate system is represented by the roll angle Pitch angle θ, yaw angle ψ. p, q, r are the rotational angular velocities of the tunnel detection AUV. Then the conversion relationship between the rotational angular velocities of the two coordinate systems can be expressed as:

[0033]

[0034] Combining equations (5) and (6), it can be obtained that:

[0035]

[0036] Among them,

[0037] R = [r T , Λ T T , r = [ξ, η, ζ] T ,

[0038] V = [U T , Ω T T , U = [u, v, w] T , Ω = [p, q, r] T .

[0039] Furthermore, the method for establishing the kinetic model is as follows: During the underwater movement of the tunnel detection AUV, it is subject to both hydrodynamic forces and rigid body forces. When modeling the dynamics of the tunnel detection AUV, it will be divided into rigid body dynamics modeling and hydrodynamic dynamics modeling;

[0040] The rigid body dynamics modeling of the tunnel detection AUV is specifically as follows:

[0041] Ignoring the effect of water on the tunnel detection AUV, the mechanical analysis of the tunnel detection AUV is carried out in the moving coordinate system through Newton's law and Euler's law of motion; the coordinate positions of the center of buoyancy and the center of gravity of the tunnel detection AUV are expressed by the following formula:

[0042]

[0043] The general expression of the 6-degree-of-freedom rigid body dynamics of the tunnel detection AUV is as follows:

[0044]

[0045] where τ RB is the external force and moment acting on the tunnel detection AUV, and τ RB is expressed by Equation (10):

[0046] τ RB = [X Y Z K M N] T (10)

[0047] M RB is the rigid body mass inertia matrix of the AUV:

[0048]

[0049] C RB (V) is the rigid body Coriolis centripetal force matrix of the AUV:

[0050]

[0051] ​​Among them, the inertia tensor matrix:

[0052]

[0053] For the convenience of calculation, define the operator S:

[0054]

[0055] For the tunnel detection AUV, the center of buoyancy coincides with the origin of the moving coordinate system, and the inertia tensor matrix I0 can be simplified to the following form:

[0056]

[0057] The hydrodynamic modeling of the tunnel detection AUV is specifically as follows: The tunnel detection AUV is subjected to the response of hydrodynamics. The external forces and moments acting on the tunnel detection AUV include the fluid force τ H , the environmental disturbance force τ E and the active control force τ:

[0058] The fluid force τ H includes the added mass, the restoring force, the fluid damping force, and the flap force;

[0059] The environmental disturbance force τ E is the action of the water flow on the tunnel detection AUV during the operation of the tunnel detection AUV in the tunnel;

[0060] The active control force τ is the force and moment generated by the actuator of the tunnel detection AUV;

[0061] Based on the above analysis, the resultant external force (moment) acting on the tunnel detection AUV can be expressed by the following equation:

[0062] τ RB = τ H + τ E + τ (16)

[0063] Among them, the fluid force τ H can be expressed as:

[0064]

[0065] The added mass inertia matrix M A is the hydrodynamic force generated by the acceleration of the tunnel detection AUV and is expressed as:

[0066]

[0067] C A (V) is the Coriolis centripetal force matrix caused by the added mass of the tunnel detection AUV:

[0068]

[0069] Among them,

[0070]

[0071] D(V) is the water damping matrix and can be expressed as:

[0072]

[0073] g(R) is the heavy buoyancy (moment) matrix and can be expressed as:

[0074]

[0075] Among them, W is the gravity of the tunnel inspection AUV, and B is the buoyancy force received by the tunnel inspection AUV.

[0076] Furthermore, in step 3, the movement of the tunnel inspection AUV is simplified into horizontal plane movement and vertical plane movement;

[0077] To complete the depth control of the AUV, first establish the AUV vertical plane kinematic model; ignore the influence of the tunnel inspection AUV's yaw, lateral translation, and roll on its movement; the depth d and heave velocity w are the variables of the movement state of the tunnel inspection AUV in the vertical plane; the vertical kinematic equation of the AUV can be simplified as:

[0078]

[0079] The dynamic equation can be expressed as:

[0080]

[0081] The hydrodynamic coefficient is the value of the partial derivative of the hydrodynamic component with respect to the AUV movement parameter at this point; for example, is the angular acceleration of rotation about the y-axis The influence coefficient of, which causes the force Z on the z-axis; I y is the moment of inertia about the y-axis, f is the disturbance in the subscript direction; τ is the force or moment generated by the actuator in the subscript direction;

[0082] After separating the vertical plane of the depth control, establish the horizontal plane dynamic model of the AUV considering the longitudinal surge, lateral surge, and yaw movement in the horizontal plane; ignore the influence of the tunnel inspection AUV's pitch, heave, and roll on its movement;

[0083] The horizontal plane kinematic equation and dynamic equation of the tunnel inspection AUV can be expressed as:

[0084]

[0085]

[0086] When the tunnel detection AUV is in steady motion, F B = 0; when the tunnel detection AUV is in other unsteady motions, F B satisfies the following equation:

[0087]

[0088] where R0 is the position vector of the tunnel detection AUV in the geodetic coordinate system, and the angular velocity vector in the moving coordinate system is represented by Ω = pe x + qe y + re z The position vector of the fluid particle is represented by r1, and the linear acceleration in the body coordinate system is represented by

[0089]

[0090] where U represents the velocity vector of the tunnel detection AUV, then represents the acceleration vector of the tunnel detection AUV;

[0091] Next, simplify the equation, adopt the K-Epsilon turbulence model, and then use the two-equation turbulence model of k-ε, where k and ε are as follows:

[0092]

[0093] where ε represents the turbulent dissipation rate, k represents the turbulent kinetic energy, and G k represents the generation term of the turbulent kinetic energy k,

[0094] C 1ε = 1.44, C 2ε = 1.92, C μ = 0.09, σ k = 1.0, σ ε = 1.3.

[0095] Furthermore, select a suitable computational domain so that the computational fluid dynamics numerical simulation can obtain sufficiently accurate numerical values, and model the computational domain for typical tunnel shapes to verify the water flow force on the tunnel detection AUV in the tunnel;

[0096] Select the cuboid and cylinder computational domains. The length of the computational domain is determined to be more than 7 times the main scale of the tunnel detection AUV, 3.78 times in front of the mid-cross section of the AUV, 3.78 times behind, and the width and height are set to the numerical values of the water conveyance tunnel section:

[0097] After setting the computational domain, perform a subtraction operation on the tunnel detection AUV and the computational domain to obtain the computational space, and then generate the mesh. Select the automatic mesh and generate a mesh that includes surface reconstruction, cutting body mesh cell generator, polyhedral mesh generator, and prism layer mesh generator;

[0098] Debug and set the boundary layer thickness, basic dimensions, and surface maximum size parameters. Create a new computational domain near the surface of the tunnel detection AUV in the two wing plates and thruster areas, and use the volume control method to perform volume encryption processing in this area. Set anisotropy to carefully monitor complex areas of the flow field and obtain higher-precision numerical values;

[0099] After three sets of mesh experiments with 500,000, 1,000,000, and 2,000,000 meshes, the number of volume meshes converges at 1,000,000; Use 1,000,000 meshes; Assign parts to regions, create regions for each part, create boundaries for each part, and generate volume meshes after setting the corresponding parameters,

[0100] During the detection process, the tunnel detection AUV maintains its plane section within the longitudinal middle section of the tunnel and sails, and opens its wing plates. When hovering at the detection point, the wing plates are closed, and the width of the tunnel detection AUV decreases. At the same time, to ensure safety and the effect of fixed-point observation, the tunnel detection AUV is generally about 0.5 m away from the wall surface during fixed-point operation. According to the flow field boundary layer thickness calculation formula:

[0101]

[0102] Among them, δ is the boundary layer thickness, K is the coefficient, U0 is the fluid velocity, x is the characteristic length, and μ is the kinematic viscosity;

[0103] The coefficient K is usually taken as 3.464. The distance of the tunnel detection AUV from the wall surface of 0.5 m is greater than the boundary layer thickness, so the flow field change range in the operation area of the tunnel detection AUV is not large;

[0104] After generating the volume mesh, it is necessary to select the physical model, including an adaptive mesh with gravity, laminar flow, constant density, etc., and use an interpolation calculation scheme to determine the boundary conditions;

[0105] The boundary conditions are set as follows: The rear side is set as a velocity inlet, and according to the tunnel conditions, a 1 m / s flow field in the tunnel; The front side is set as an outlet and is set as a pressure outlet; The tunnel detection AUV is set as a wall boundary condition; The four surrounding boundary conditions of the computational domain are set as walls.

[0106] Furthermore, in step 4, it also includes the analysis of the force effect on the wing plates and the numerical simulation of the straight-line navigation force,

[0107] The force effect analysis of the wing plate is to simulate and analyze the forces before and after adding the wing plate. Since the tunnel inspection AUV uses the wing plate to utilize the water flow, the water flow is set to flow from the tail of the AUV to the bow, and the oncoming flow field is 1 m / s, and the force situation is calculated.

[0108] The straight-line navigation force numerical simulation is that when conducting tunnel inspection, the AUV model does not move, and the change of the rear flow velocity is set, so as to obtain the force situation of the tunnel inspection AUV at different flow velocities.

[0109] When the velocity difference between the tunnel inspection AUV and the water flow is large, it can receive a large thrust as power. Based on this, it is necessary to fit the power received by the tunnel inspection AUV, and the method used is the least squares method.

[0110] An optimization system for a water conveyance tunnel inspection AUV model:

[0111] The system includes a conversion module, an AUV model simplification module, and an optimization module;

[0112] The conversion module defines the motion coordinate system and the geodetic coordinate system of the tunnel inspection AUV according to the operation environment, and obtains the conversion relationship of the coordinate system according to the motion parameters of the tunnel inspection AUV.

[0113] The AUV model simplification module establishes the kinematic model and dynamic model of the tunnel inspection AUV according to the data of the conversion module; simplifies the mathematical model of the tunnel inspection AUV, and conducts a force analysis of the tunnel inspection AUV.

[0114] The optimization module uses SOLIDWORKS 3D modeling software to establish a tunnel inspection AUV model, checks its effectiveness, and repairs it if there are problems, completing the optimization of the tunnel inspection AUV model.

[0115] An electronic device includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, the steps of the above method are implemented.

[0116] A computer-readable storage medium is used to store computer instructions, and when the computer instructions are executed by a processor, the steps of the above method are implemented.

[0117] Advantages of the present invention

[0118] The present invention first selects a coordinate system suitable for tunnel inspection AUV, explains the physical quantities involved in the modeling and motion of the tunnel inspection AUV, introduces the conversion formula between the geodetic coordinate system and the motion coordinate system, then establishes the kinematic and dynamic models of the tunnel inspection AUV, and simplifies them into vertical plane and horizontal plane models; establishes a simulation model of the tunnel inspection AUV and the water conveyance tunnel, conducts straight navigation force tests on two typical cross-sections of the water conveyance tunnel under the condition that the tunnel inspection AUV spreads its wing plates, and finally fits the functional relationship between force and relative flow velocity by the least square method to obtain the functional relationship of the water flow acting force on the tunnel inspection AUV under the condition that the tunnel inspection AUV spreads its wing plates.

[0119] When drifting, the tunnel inspection AUV spreading its wing plates can reach a stable drifting state more quickly, reduce the operation time of the thruster and other load devices, and save energy consumption; when conducting fixed-point observation, the tunnel inspection AUV closing its wing plates can reduce the water flow resistance, reduce the propulsion power of the thruster, and save the energy consumption of the thruster. Brief Description of the Drawings

[0120] Figure 1 Schematic diagram of the tunnel inspection AUV of the present invention;

[0121] Figure 2 The tunnel inspection AUV of the present invention and its coordinate system;

[0122] Figure 3 Mesh division diagram of the tunnel inspection AUV body;

[0123] Figure 4 Schematic diagram of the cross-sectional shape of a typical tunnel;

[0124] Figure 5 Cylindrical calculation domain;

[0125] Figure 6 Cube calculation domain;

[0126] Figure 7 Force diagrams of different meshes;

[0127] Figure 8 Flow field diagram 2m in front of the central axis of the AUV;

[0128] Figure 9 Flow field diagram at the propeller shaft of the AUV;

[0129] Figure 10 Force fitting diagram. Detailed Implementation Modes

[0130] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0131] Combined with Figures 1 to 10 , in the embodiment, as Figure 1 shown, the tunnel inspection AUV has a total length of 2.91 meters, a maximum body diameter of 0.60 meters, a width of 1.10 meters including the wing plates on both sides, and the wing plates have an opening angle of 15°. The whole hull is designed in a spindle shape and is equipped with twelve thrusters. Among them, four main thrusters are arranged at the head and the tail respectively for forward and backward movement, and one vertical thruster and one lateral thruster are equipped at the head and the tail respectively. The two vertical thrusters are responsible for the diving and floating movement, and the two lateral thrusters are responsible for the lateral movement. A pair of wing plates are equipped in the middle, and the wing plates are designed in a conformal shape. After the wing plates are closed, the whole hull is streamlined.

[0132] The tunnel environment is complex, there is a foreseeable flow field, and the motion model of the tunnel inspection AUV with drifting wing plates has problems of nonlinearity and high coupling. Computational fluid dynamics simulation is carried out using STAR-CCM+ to obtain the kinematic and dynamic models of the tunnel inspection AUV.

[0133] An optimization method for the model of a water conveyance tunnel inspection AUV: The method specifically includes the following steps:

[0134] Step 1, define the moving coordinate system and the earth coordinate system of the tunnel inspection AUV according to the working environment, and obtain the conversion relationship between the coordinate systems according to the motion parameters of the tunnel inspection AUV.

[0135] In step 1, the tunnel inspection AUV is regarded as a rigid body, and its motion is decomposed into a set of spatial motions of its center of buoyancy and a set of rotations around its center of buoyancy; for the tunnel inspection AUV, the coordinate systems recommended by the International Towing Tank Conference (ITTC) and the terminology bulletin of the Society of Naval Architects and Marine Engineers (SNAME) are selected.

[0136] Two coordinate systems determined by the right-hand rule system: the moving coordinate system is B-xyz, which is fixedly connected to the tunnel inspection AUV and moves with the tunnel inspection AUV; the earth coordinate system is E-ξηζ, which is fixedly connected to the earth; the coordinate system is shown as Figure 2 shown;

[0137] The earth coordinate system E-ξηζ: The origin E is selected as a fixed point on the earth, generally the starting position of the AUV. The Eξ axis is located in the horizontal plane, and the main course of the tunnel inspection AUV is taken as the positive direction; the Eζ axis is perpendicular to the ξEη coordinate plane, and the direction pointing to the center of the earth is positive. The Eη axis is located in the horizontal plane where the Eξ axis is located, and the Eξ axis is rotated clockwise by 90° according to the right-hand rule.

[0138] The moving coordinate system is B-xyz: Set the center of buoyancy of the tunnel inspection AUV as the origin B. Then, the Bx-axis lies on the intersection line of the waterplane passing through point B and the longitudinal midsection, pointing in the forward movement direction of the tunnel inspection AUV. The By-axis lies on the intersection line of the cross-section passing through point B and the waterplane. The By-axis is perpendicular to the Bx-axis and points from the left wing direction to the right wing direction. The Bz-axis lies on the intersection line of the cross-section passing through point B and the longitudinal midsection, pointing downward of the tunnel inspection AUV, and the positive direction follows the right-hand rule.

[0139] Since the moving coordinate system is fixedly connected to the body of the tunnel inspection AUV, the movement of the tunnel inspection AUV can be transformed into the movement relationship of the moving coordinate system relative to the earth coordinate system (inertial coordinate system).

[0140] The position of the tunnel inspection AUV is represented by the coordinates (ξ B , η B , ζ B ) of the origin of the moving coordinate system in the earth coordinate system. The attitude of the tunnel inspection AUV can be represented by three angles for the transformation between the moving coordinate system and the earth coordinate system: roll angle , pitch angle θ, and yaw angle ψ. The representation methods are as follows:

[0141] Roll angle The projection of the angle formed by the Eη-axis and the By-axis in the ηEζ plane, and the positive direction is that the Eη-axis rotates clockwise to the By-axis.

[0142] Pitch angle θ: The projection of the angle formed by the Eξ-axis and the Bx-axis in the vertical plane, and the positive direction is that the Eξ-axis rotates counterclockwise to the Bx-axis.

[0143] Yaw angle ψ: The projection of the angle formed by the Eξ-axis and the Bx-axis in the horizontal plane, and the positive direction is that the Eξ-axis rotates clockwise to the Bx-axis.

[0144] The movement of the tunnel inspection AUV is a six-degree-of-freedom spatial movement. The vector representation methods for the six-degree-of-freedom movement with respect to each coordinate are as follows:

[0145] Table 1 Six-degree-of-freedom movement variable table of the tunnel inspection AUV

[0146]

[0147] According to the roll angle , pitch angle θ, and yaw angle ψ, the two coordinate systems are transformed by three rotations.

[0148] First, rotate by ψ around the Eζ-axis, Eξ → Bx1, Eη → By1, then:

[0149]

[0150] Then rotate by θ around the By1 axis, Bx1 → Bx, Eζ → Bz1, then:

[0151]

[0152] Finally, rotate around the Bx axis By1 → By, Bz1 → Bz, then:

[0153]

[0154] Combining and superimposing equations (1) to (3), we can obtain

[0155]

[0156] Step 2: Establish the kinematic model and dynamic model of the tunnel detection AUV according to the data in Step 1;

[0157] The method for establishing the kinematic model is as follows: The coordinates of the tunnel detection AUV in the geodetic coordinate system are (ξ B , η B , ζ B ), and its speed is set as The speeds of the tunnel detection AUV in the three directions in the moving coordinate system are (u, v, w). Then the conversion relationship between the speeds of the two coordinate systems can be expressed as:

[0158]

[0159] The attitude of the tunnel detection AUV in the geodetic coordinate system is represented by the roll angle , pitch angle θ, and yaw angle ψ. p, q, r are the rotational angular velocities of the tunnel detection AUV. Then the conversion relationship between the rotational angular velocities of the two coordinate systems can be expressed as:

[0160]

[0161] Combining equations (5) and (6), we can obtain:

[0162]

[0163] Among them,

[0164] R = [r T , Λ T T , r = [ξ, η, ζ] T ,

[0165] V = [U T , Ω T T , U = [u, v, w] T ​​, Ω = [p, q, r] T ;

[0166] The method for establishing the dynamic model is as follows: During the underwater movement of the tunnel detection AUV, it is affected by both hydrodynamic forces and rigid body forces. When performing dynamic modeling of the tunnel detection AUV, the effects of both need to be considered. When performing dynamic modeling of the tunnel detection AUV, it is divided into rigid body dynamics modeling and hydrodynamic dynamics modeling;

[0167] The specific rigid body dynamics modeling of the tunnel detection AUV is as follows:

[0168] In this part, the effect of water on the tunnel detection AUV is ignored, and the mechanical analysis of the tunnel detection AUV in the moving coordinate system is carried out through Newton's law and Euler's law of motion. The coordinate positions of the center of buoyancy and the center of gravity of the tunnel detection AUV are expressed by the following formula:

[0169]

[0170] The general expression of the 6-degree-of-freedom rigid body dynamics of the tunnel detection AUV is as follows:

[0171]

[0172] where τ RB is the external force and moment acting on the tunnel detection AUV, and τ RB is expressed by Equation (10):

[0173] τ RB = [X Y Z K M N] T (10)

[0174] M RB is the rigid body mass inertia matrix of the AUV:

[0175]

[0176] C RB (V) is the rigid body Coriolis centripetal force matrix of the AUV:

[0177]

[0178] Among them, the inertia tensor matrix:

[0179]

[0180] For the convenience of calculation, the operator S is defined:

[0181]

[0182] For the tunnel inspection AUV, the center of buoyancy coincides with the origin of the moving coordinate system, and the inertia tensor matrix I0 can be simplified into the following form:

[0183]

[0184] The hydrodynamic modeling of the tunnel inspection AUV is specifically as follows: mainly, the response of the tunnel inspection AUV to hydrodynamics is considered. The external forces and torques acting on the tunnel inspection AUV include the fluid force τ H , the environmental disturbance force τ E and the active control force τ:

[0185] The fluid force τ H includes added mass, restoring force (the action of buoyancy and gravity), fluid damping force and flap force.

[0186] The environmental disturbance force τ E is the influence of the environment such as current, wave and wind. For the tunnel inspection AUV studied in the present invention, the action of the water flow on the tunnel inspection AUV during its operation in the tunnel is considered.

[0187] The active control force τ is the force and torque generated by the actuator of the tunnel inspection AUV.

[0188] Based on the above analysis, the resultant external force (torque) acting on the tunnel inspection AUV can be expressed by the following equation:

[0189] τ RB =τ H +τ E +τ (16)

[0190] Among them, the fluid force τ H can be expressed as:

[0191]

[0192] The added mass inertia matrix M A is the hydrodynamic force generated by the accelerated motion of the tunnel inspection AUV, and is expressed as:

[0193]

[0194] C A (V) is the Coriolis centripetal force matrix caused by the added mass of the tunnel inspection AUV:

[0195]

[0196] Among them,

[0197]

[0198] D(V) is the water damping matrix and can be expressed as:

[0199]

[0200] g(R) is the heavy buoyancy (moment) matrix and can be expressed as:

[0201]

[0202] Where W is the gravity of the tunnel inspection AUV, and B is the buoyancy force received by the tunnel inspection AUV.

[0203] Some parameters of the tunnel inspection AUV are obtained after the design is completed, such as the mass m and the inertia I z , for the added mass of hydrodynamic force The viscous damping term X u , Y v , N r , are obtained from other research work. Since the influence of the viscous damping coefficient above the second order on the control system in tunnel inspection is very small, the viscous damping coefficient above the second order is ignored in the present invention.

[0204] Step 3, according to the kinematic model and dynamic model in Step 2, simplify the mathematical model of the tunnel inspection AUV and conduct a force analysis on the tunnel inspection AUV;

[0205] From the working environment and its own motion characteristics of the tunnel inspection AUV, it is difficult to establish its accurate mathematical model. Even if some researchers can design a sufficiently accurate mathematical model, this model is often too complex and not suitable for the design of the control system. Therefore, the model needs to be simplified. When the influence of the roll motion and the coupling between the two planar motions in the vertical plane and the horizontal plane is relatively small, the influence of these two aspects is ignored, and the AUV is simplified to the horizontal plane motion and the vertical plane motion.

[0206] The underwater environment is complex. It is impossible to study the tunnel inspection AUV under the ideal state without interference. There are many types of interferences, and the most important one is the influence of water flow. The sum of various interferences is fully considered. The following premise assumptions are given:

[0207] (1) The influence of the high-order hydrodynamic coefficients of the tunnel inspection AUV is very small and is ignored;

[0208] (2) The mass of each part of the tunnel inspection AUV is equal;

[0209] (3) The center of gravity and the center of buoyancy of the tunnel inspection AUV are on the same vertical line.

[0210] To complete the depth control of the AUV, first establish the kinematic model of the AUV in the vertical plane. Ignore the influence of the yaw, sway, and roll of the tunnel detection AUV on its motion. The depth d and heave velocity w are the variables of the motion state of the tunnel detection AUV in the vertical plane. The vertical kinematic equation of the AUV can be simplified as:

[0211]

[0212] The dynamic equation can be expressed as:

[0213]

[0214] The hydrodynamic coefficient is the value of the partial derivative of the hydrodynamic component with respect to the AUV motion parameter at this point. For example, is the angular acceleration of rotation about the y-axis The influence coefficient of, which causes the force Z on the z-axis. I y is the moment of inertia about the y-axis, f is the disturbance in the subscript direction. τ is the force or moment generated by the actuator in the subscript direction.

[0215] After separating the vertical plane of the depth control, establish the hydrodynamic model of the horizontal plane considering the surge, sway, and yaw motions of the AUV in the horizontal plane. Ignore the influence of the pitch, heave, and roll of the tunnel detection AUV on its motion.

[0216] The kinematic equation and dynamic equation of the tunnel detection AUV in the horizontal plane can be expressed as:

[0217]

[0218]

[0219] Considering multiple factors such as comprehensive cost, the force condition of the tunnel detection AUV is simulated numerically by computational fluid dynamics, using the STAR-CCM+ software.

[0220] The numerical simulation of computational fluid dynamics follows three conservation laws: the law of conservation of mass, the law of conservation of momentum, and the law of conservation of energy. These conservation laws in physics can be expressed through the control equations. The expressions of the control equations are as follows:

[0221]

[0222] where U represents the instantaneous velocity of the fluid, which can be decomposed into the pulsating velocity component u i ' and the mean velocity component U i , ρ represents the fluid density, μ represents the fluid viscosity coefficient, and P represents the instantaneous mean pressure of the fluid. The Reynolds stress is determined after being selected by the k-ω turbulence model

[0223] When the tunnel detection AUV is in steady motion, F B = 0. When the tunnel detection AUV is in other unsteady motions, F B satisfies the following equation:

[0224]

[0225] where R0 is the position vector of the tunnel detection AUV in the geodetic coordinate system, and the angular velocity vector in the moving coordinate system is represented by Ω = pe x + qe y + re z The position vector of the fluid particle is represented by r1, and the linear acceleration in the body coordinate system is represented by

[0226]

[0227] where U represents the velocity vector of the tunnel detection AUV, then represents the acceleration vector of the tunnel detection AUV.

[0228] Next, simplify the equation, adopt the K-Epsilon turbulence model, and then use the k-ε two-equation turbulence model, where k and ε are as follows:

[0229]

[0230] where ε represents the turbulent dissipation rate, k represents the turbulent kinetic energy, and G k represents the generation term of the turbulent kinetic energy k,

[0231] C 1ε = 1.44, C 2ε = 1.92, C μ = 0.09, σ k = 1.0, σ ε = 1.3.

[0232] Step 4: Use SOLIDWORKS 3D modeling software to establish the tunnel detection AUV model, establish parallelism on the local host in STAR-CCM+, import the established model into the software, check the validity of the model, repair it if there are problems, and simplify the structure at the same time;

[0233] Select a suitable computational domain so that the computational fluid dynamics numerical simulation can obtain sufficiently accurate numerical values. Selecting a smaller computational domain will affect the accuracy, but a too large computational domain will cause problems with slow simulation. Select a suitable computational domain according to the vehicle and the environment.

[0234] In the embodiment, the total length of the tunnel detection AUV is 2.91 m, the maximum diameter of the main body is 0.60 m, and the width including the wing plates is 1.10 m.

[0235] According to the reference materials and the actual situation of the water conveyance tunnel, there are two relatively typical tunnel shapes, as Figure 4 shown. The computational domains are modeled for the typical tunnel shapes respectively to verify the water flow forces acting on the tunnel detection AUV in the tunnel.

[0236] According to the tunnel conditions, cuboid and cylinder computational domains are selected. The length of the computational domain is determined to be more than 7 times the main scale of the tunnel detection AUV, 3.78 times in front of the cross-section in the middle of the AUV and 3.78 times behind it. The width and height are set to the values of the water conveyance tunnel cross-section. Then the generated computational domain parameters are shown in the following table:

[0237] Table 2 Dimensions of the cylindrical tunnel

[0238]

[0239] Table 3 Dimensions of the cuboid tunnel

[0240]

[0241]

[0242] After setting the computational domain, the tunnel detection AUV and the computational domain are subtracted to obtain the computational space, and then the grid is generated. The automatic grid is selected to generate a grid including a surface reconstruction, a cutting body mesh cell generator, a polyhedron mesh generator, and a prism layer mesh generator.

[0243] The parameters such as the boundary layer thickness, basic dimensions, and maximum surface dimensions are debugged and set. New computational domains are created in the areas near the surface of the tunnel detection AUV, such as the two wing plates and the thrusters. The volume control method is used to perform volume encryption processing in this area, and anisotropy is set to monitor the complex areas of the flow field in detail and obtain higher-precision values.

[0244] After experiments with three sets of grids (500,000, 1,000,000, 2,000,000), the number of volume grids converges at 1,000,000. The 1,000,000-grid is adopted. The parts are assigned to regions, and regions are created for each part. Boundaries are created for each part. After setting the corresponding parameters, volume grids are generated. The two computational domains are as Figure 5 、 7 shown.

[0245] During the detection process, the tunnel detection AUV sails as much as possible within the longitudinal mid-section plane of the tunnel, with its wing plates extended. When hovering at the detection point, the wing plates are closed considering the ease of control and energy conservation, reducing the width of the tunnel detection AUV to 0.6 m. At the same time, to ensure safety and the effect of fixed-point observation, the tunnel detection AUV is generally about 0.5 m away from the wall surface during fixed-point operation. According to the formula for calculating the thickness of the flow field boundary layer:

[0246]

[0247] where δ is the boundary layer thickness, K is the coefficient, U0 is the fluid velocity, x is the characteristic length, and μ is the kinematic viscosity.

[0248] The coefficient K is usually taken as 3.464. The distance of the tunnel detection AUV from the wall surface of 0.5 m is greater than the boundary layer thickness, so the change range of the flow field in the operation area of the tunnel detection AUV is not large.

[0249] After generating the body grid, it is necessary to select the physical model, including the adaptive grid with gravity, laminar flow, constant density, etc., and adopt the interpolation calculation scheme. Then, determine the boundary conditions, which are set as follows:

[0250] (1) The rear side is set as the velocity inlet, and according to the tunnel conditions, a flow field of 1 m / s in the tunnel;

[0251] (2) The front side is set as the outlet and is set as the pressure outlet;

[0252] (3) The tunnel detection AUV is set as the wall boundary condition;

[0253] (4) The boundary conditions of the four sides of the computational domain are set as walls.

[0254] In step 4, it also includes the analysis of the force effect of the wing plates and the numerical simulation of the straight-line navigation force;

[0255] The analysis of the force effect of the wing plates is to simulate and analyze the forces before and after adding the wing plates. Since the tunnel detection AUV uses the wing plates to utilize the water flow, the water flow is set to flow from the tail of the AUV to the bow, and the oncoming flow is a flow field of 1 m / s, as Figure 8 、 10 , and calculate the force conditions.

[0256] In the case where the computational domain is a cuboid tunnel, the forces before and after adding the wing plates and at different positions are shown in the following table:

[0257] Table 4 Force table in the cuboid computational domain

[0258]

[0259] In the case where the computational domain is a cylindrical tunnel, the forces before and after adding the wing plates and at different positions are shown in the following table:

[0260] Table 5 Force Table in the Calculation Domain of the Cylinder

[0261]

[0262] As can be seen from the table, the tunnel inspection AUV with wing plates can make better use of the water flow force under two common tunnel shapes, and the force received is about 4 times that without wing plates.

[0263] Thus, it can be seen that when the tunnel inspection AUV is drifting, opening the wing plates can reach the stable drifting state more quickly, reduce the operation time of the thruster and other load devices, and save energy consumption; when performing fixed-point observation, closing the wing plates of the tunnel inspection AUV can reduce the water flow resistance, reduce the propulsion power of the thruster, and save the energy consumption of the thruster.

[0264] The above-mentioned straight-line navigation force numerical simulation is to keep the AUV model stationary during tunnel inspection, set the change of the rear flow velocity, and then obtain the force condition of the tunnel inspection AUV at different flow velocities. Considering the comprehensive requirements of safe obstacle avoidance and the normal operation of detection equipment such as sonar, the working speed of the AUV is limited to 0 - 1 m / s. In the actual water conveyance tunnel inspection scenario, by controlling the flow velocity through gates and other means, under the condition of meeting industrial and domestic water use, the flow velocity can be controlled at about 1 m / s to facilitate the inspection of the tunnel inspection AUV. The water flow simulation of the tunnel inspection AUV is carried out from the back to the front, with a graduation value of 0.1 m / s and a range of 0 - 1 m / s. The experimental data are as follows in the table:

[0265] Table 6 Straight-line Navigation Force Table of Tunnel Inspection AUV

[0266]

[0267] According to the obtained data, it can be seen that when the velocity difference between the tunnel inspection AUV and the water flow is large, it can receive a large thrust as power. Based on this, it is necessary to fit the power received by the tunnel inspection AUV, and the least squares method is used. The correlation coefficient R 2 is greater than 0.999, proving that the fitting effect is excellent.

[0268] Then the fitting function is:

[0269]

[0270] v c = v w - v AUV (33)

[0271] where F w is the straight-line navigation resistance received by the tunnel inspection AUV when the wing plates are opened, and v c is the velocity of the AUV relative to the water flow.

[0272] Table 7 Fitting Table of Forces Acting on the Tunnel Detection AUV

[0273]

[0274]

[0275] As can be seen from the above fitting graph, the trend of the fitting function is smooth, the square of the correlation coefficient R is close to 1, the error is all below 0.5%, the fitting effect is excellent, the thrust received by the tunnel detection AUV is proportional to the square of the flow velocity, which is the same as the empirical formula, and based on this formula as part of the tunnel detection AUV model, making it more accurate. The force acting on the cuboid-shaped tunnel is in the same form and not much different in magnitude from that on the cylindrical tunnel, and in the water conveyance tunnel, the cylindrical tunnel with a circular cross-section is more common.

[0276] An optimization system for the water conveyance tunnel detection AUV model:

[0277] The system includes a conversion module, an AUV model simplification module, and an optimization module;

[0278] The conversion module defines the moving coordinate system and the geodetic coordinate system of the tunnel detection AUV according to the operation environment, and obtains the conversion relationship of the coordinate system according to the motion parameters of the tunnel detection AUV;

[0279] The AUV model simplification module establishes the kinematic model and dynamic model of the tunnel detection AUV according to the data of the conversion module; simplifies the mathematical model of the tunnel detection AUV, and conducts a force analysis on the tunnel detection AUV;

[0280] The optimization module uses SOLIDWORKS 3D modeling software to establish the tunnel detection AUV model, checks its effectiveness, repairs it if there are problems, and completes the optimization of the tunnel detection AUV model.

[0281] An electronic device includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, the steps of the above method are implemented.

[0282] A computer-readable storage medium is used to store computer instructions, and when the computer instructions are executed by a processor, the steps of the above method are implemented.

[0283] The memory in the embodiments of the present application can be a volatile memory or a non-volatile memory, or can include both volatile and non-volatile memories. Among them, the non-volatile memory can be a read only memory (ROM), a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), or a flash memory. The volatile memory can be a random access memory (RAM), which is used as an external cache. By way of example but not limitation, many forms of RAM are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchlink DRAM (SLDRAM), and direct rambus RAM (DR RAM). It should be noted that the memory of the method described in the present invention is intended to include but not limited to these and any other suitable types of memories.

[0284] The above has introduced in detail an optimization method for an AUV model for detecting water conveyance tunnels proposed by the present invention, and has elaborated on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. An optimization method for the detection AUV model of a water conveyance tunnel, characterized in that: The method specifically includes the following steps: Step 1, define the moving coordinate system and the geodetic coordinate system of the tunnel detection AUV according to the working environment, and obtain the conversion relationship between the coordinate systems according to the motion parameters of the tunnel detection AUV; Step 2, establish the kinematic model and dynamic model of the tunnel detection AUV according to the data in Step 1; Step 3, simplify the mathematical model of the tunnel detection AUV according to the kinematic model and dynamic model in Step 2, and conduct a force analysis of the tunnel detection AUV; In Step 3, the motion of the tunnel detection AUV is simplified into horizontal plane motion and vertical plane motion; In order to complete the depth control of the AUV, first establish the AUV vertical plane kinematic model; ignore the influence of the yaw, sway and roll of the tunnel detection AUV on its motion; the depth d and heave velocity w are variables of the motion state in the vertical plane of the tunnel detection AUV; the vertical kinematic equation of the AUV can be simplified as: The dynamic equation can be expressed as: The hydrodynamic coefficient is the value of the partial derivative of the hydrodynamic component with respect to the AUV motion parameter at that point; is the angular acceleration about the y-axis influence coefficient, which causes a force Z on the z-axis; I y is the moment of inertia about the y-axis, f is the disturbance in the subscript direction; τ is the force or torque generated by the actuator in the subscript direction; After separating the vertical plane of the depth control, establish a horizontal plane dynamic model considering the surge, sway and yaw motions of the AUV in the horizontal plane; ignore the influence of the pitch, heave and roll of the tunnel detection AUV on its motion; The horizontal plane kinematic equation and dynamic equation of the tunnel detection AUV can be expressed as: When the tunnel detection AUV is in steady motion, F B = 0; when the tunnel detection AUV is in other unsteady motions, F B satisfies the following equation: where R0 is the position vector of the tunnel detection AUV in the geodetic coordinate system, and the angular velocity vector in the moving coordinate system is represented by Ω = pe x + qe y + re z The position vector of the fluid particle is represented by r1, and the linear acceleration in the body coordinate system is represented by where U represents the velocity vector of the tunnel inspection AUV, then represents the acceleration vector of the tunnel inspection AUV; Next, simplify the equation, adopt the K-Epsilon turbulence model, and then use the k-ε two-equation turbulence model, where k and ε are as follows: where ε represents the turbulent dissipation rate, k represents the turbulent kinetic energy, and G k represents the generation term of the turbulent kinetic energy k C 1ε = 1.44, C 2ε = 1.92, C μ = 0.09, σ k = 1.0, σ ε = 1.3; Step 4, use SOLIDWORKS 3D modeling software to establish the tunnel detection AUV model, check its effectiveness, and complete the optimization of the tunnel detection AUV model; In Step 4, it also includes the wing plate force effect analysis and the straight-ahead force numerical simulation, The wing plate force effect analysis is to simulate and analyze the forces before and after adding the wing plate. Since the tunnel detection AUV uses the wing plate to utilize the water flow, the water flow is set to flow from the tail of the AUV to the bow, and the incoming flow is a flow field of 1 m / s, and the force situation is calculated; The straight-ahead force numerical simulation is to keep the AUV model stationary during the tunnel detection, set the change of the rear flow velocity, and then obtain the force situation of the tunnel detection AUV at different flow velocities; Fit the power received by the tunnel detection AUV, and the method used is the least squares method.

2. According to the method described in Claim 1, characterized in that: In Step 1, regard the tunnel detection AUV as a rigid body, and decompose its motion into a set of spatial motions of its center of buoyancy and a set of rotations around its center of buoyancy; Two coordinate systems determined by the right-hand rule system: the moving coordinate system is B-xyz, which is fixedly connected to the tunnel detection AUV and moves with the tunnel detection AUV; the geodetic coordinate system is E-ξηζ, which is fixedly connected to the earth; The geodetic coordinate system E-ξηζ: The origin E is selected as a fixed point on the earth, the Eξ axis is located in the horizontal plane, and the main course of the tunnel detection AUV is the positive direction; the Eζ axis is perpendicular to the ξEη coordinate plane, and the direction pointing to the center of the earth is positive, and the Eη axis is located in the horizontal plane where the Eξ axis is located, and the Eξ axis is rotated clockwise by 90° according to the right-hand rule; The moving coordinate system is B-xyz: Set the center of buoyancy of the tunnel inspection AUV as the origin B. Then the Bx-axis lies on the intersection line of the waterplane passing through point B and the longitudinal midsection, pointing in the forward movement direction of the tunnel inspection AUV. The By-axis lies on the intersection line of the cross-section passing through point B and the waterplane. The By-axis is perpendicular to the Bx-axis and points from the left wing plate to the right wing plate. The Bz-axis lies on the intersection line of the cross-section passing through point B and the longitudinal midsection, pointing downward from the tunnel inspection AUV. The positive direction follows the right-hand rule. Since the moving coordinate system is fixedly connected to the body of the tunnel inspection AUV, the motion of the tunnel inspection AUV can be transformed into the motion relationship of the moving coordinate system relative to the earth coordinate system. The position of the tunnel inspection AUV is represented by the coordinates (ξ B , η B , ζ B ) of the origin of the moving coordinate system in the geodetic coordinate system; the attitude of the tunnel inspection AUV can be represented by three angles for the conversion between the moving coordinate system and the geodetic coordinate system: roll angle pitch angle θ, yaw angle ψ, and the representation method is as follows: Roll angle The projection of the angle formed by the Eη axis and the By axis in the ηEζ plane, with the positive direction being the clockwise rotation of the Eη axis to the By axis; Pitch angle θ: The projection of the angle formed by the Eξ-axis and the Bx-axis in the vertical plane. The positive direction is the counterclockwise rotation of the Eξ-axis to the Bx-axis. Yaw angle ψ: The projection of the angle formed by the Eξ-axis and the Bx-axis in the horizontal plane. The positive direction is the clockwise rotation of the Eξ-axis to the Bx-axis. According to the roll angle Pitch angle θ, yaw angle ψ, the two coordinate systems are transformed by three rotations; First, rotate by ψ around the Eζ-axis, Eξ→Bx1, Eη→By1, then: Then, rotate by θ around the By1-axis, Bx1→Bx, Eζ→Bz1, then: Finally, rotate around the Bx axis By1 → By, Bz1 → Bz, then: Combining and superimposing equations (1) to (3), we can obtain:

3. The method according to claim 2, wherein: In step 2, The method for establishing the kinematic model is as follows: The coordinates of the tunnel detection AUV in the geodetic coordinate system are (ξ B , η B , ζ B ), and its speed is set to The speeds of the tunnel detection AUV in three directions in the moving coordinate system are (u, v, w). Then, the conversion relationship between the speeds of the two coordinate systems can be expressed as: The attitude of the tunnel detection AUV in the geodetic coordinate system is represented by the roll angle pitch angle θ, and yaw angle ψ. Let p, q, and r be the rotational angular velocities of the tunnel detection AUV. Then the conversion relationship between the rotational angular velocities of the two coordinate systems can be expressed as: Combining equations (5) and (6), we can get: Where, R = [r T , Λ T T , r = [ξ, η, ζ] T , ​ V = [U T , Ω T T , U = [u, v, w] T , Ω = [p, q, r] T .​ 4. The method according to claim 3, characterized in that: The method for establishing the dynamic model is as follows: During the underwater movement of the tunnel inspection AUV, it is subject to both hydrodynamic forces and rigid body dynamic forces. When modeling the dynamics of the tunnel inspection AUV, it will be divided into rigid body dynamics modeling and hydrodynamic dynamics modeling. The specific rigid body dynamics modeling of the tunnel inspection AUV is as follows: Neglect the action of water on the tunnel inspection AUV, and conduct a mechanical analysis of the tunnel inspection AUV in the moving coordinate system through Newton's law and Euler's motion law. The coordinate positions of the center of buoyancy and the center of gravity of the tunnel inspection AUV are expressed by the following formula: The 6-degree-of-freedom rigid body dynamics expression of the tunnel inspection AUV is as follows: where τ RB is the external force and moment acting on the tunnel inspection AUV, and τ RB is expressed by Equation (10): τ RB = [X Y Z K M N] T (10) M RB is the rigid body mass inertia matrix of the AUV: C RB (V) is the rigid body Coriolis centripetal force matrix of the AUV: Where, the inertia tensor matrix: For the convenience of calculation, define the operator S: The center of buoyancy of the tunnel inspection AUV coincides with the origin of the moving coordinate system, and the inertia tensor matrix I0 can be simplified to the following form: The specific hydrodynamic modeling of the tunnel inspection AUV is as follows: The tunnel inspection AUV is subjected to the response of hydrodynamics. The external forces and torques acting on the tunnel inspection AUV include the fluid acting force τ H , the environmental interference force τ E and the active control force τ: The fluid acting force τ H , including added mass, restoring force, fluid damping force and vane acting force; The environmental interference force τ E , i.e., the effect of the water flow on the tunnel inspection AUV during the operation of the tunnel inspection AUV in the tunnel; The active control force τ is the force and moment generated by the actuator of the tunnel inspection AUV. Based on the above analysis, the resultant external force on the tunnel inspection AUV can be expressed by the following equation: τ RB = τ H + τ E + τ(16) Among them, the fluid force τ H can be expressed as: Added mass inertia matrix M A is the hydrodynamic force generated by the accelerated motion of the tunnel inspection AUV, expressed as: C A (V) is the Coriolis centripetal force matrix caused by the added mass of the tunnel detection AUV: Where, D(V) is the water damping matrix and can be expressed as: g(R) is the heavy buoyancy matrix and can be expressed as: Where W is the gravity of the tunnel inspection AUV and B is the buoyancy force received by the tunnel inspection AUV.

5. The method according to claim 4, characterized in that: Perform computational domain modeling on the tunnel shape. Select a cuboid and a cylinder computational domain. The length of the computational domain is determined to be more than 7 times the main scale of the tunnel inspection AUV, 3.78 times in front of the midsection of the AUV and 3.78 times behind it. The width and height are set to the values of the cross-section of the water conveyance tunnel. After setting up the computational domain, perform a subtraction operation on the tunnel detection AUV and the computational domain to obtain the computational space, and then generate the mesh. Select the automatic mesh and generate a mesh that includes a surface reconstruction, a cutting body mesh cell generator, a polyhedral mesh generator, and a prism layer mesh generator; Debug and set the boundary layer thickness, basic dimensions, and surface maximum dimension parameters. Create a new computational domain near the surface of the tunnel detection AUV in the two wing plates and thruster regions, and use the volume control method to perform volume encryption processing in this region. Set anisotropy to closely monitor complex areas of the flow field and obtain high-precision values; After three sets of mesh experiments with 500,000, 1,000,000, and 2,000,000 meshes, the number of volume meshes converges at 1,000,000; Use 1,000,000 meshes; Assign parts to regions, create regions for each part, create boundaries for each part, and generate volume meshes after setting the corresponding parameters; During the detection process, the tunnel detection AUV maintains its plane section within the longitudinal middle section of the tunnel and sails, and spreads its wing plates. When hovering at the detection point, the wing plates are closed, and the width of the tunnel detection AUV decreases. At the same time, to ensure safety and the effect of fixed-point observation, the tunnel detection AUV is about 0.5 m away from the wall surface during fixed-point operation. According to the flow field boundary layer thickness calculation formula: where δ is the boundary layer thickness, K is the coefficient, U0 is the fluid velocity, x is the characteristic length, and μ is the kinematic viscosity; The coefficient K is taken as 3.

464. The distance of the tunnel detection AUV from the wall surface of 0.5 m is greater than the boundary layer thickness, so the flow field change range in the operation area of the tunnel detection AUV is not large; After generating the volume mesh, it is necessary to select a physical model, including gravity, laminar flow, and adaptive mesh with constant density, and use an interpolation calculation scheme to determine the boundary conditions; The boundary conditions are set as follows: The rear surface is set as a velocity inlet, and according to the tunnel situation, the flow field of the tunnel is 1 m / s; The front surface is set as an outlet and is set as a pressure outlet; The tunnel detection AUV is set as a wall boundary condition; The boundary conditions of the four sides of the computational domain are set as walls.

6. An optimization system for an optimization method of a water conveyance tunnel detection AUV model according to any one of claims 1 to 5, characterized in that: The system includes a conversion module, an AUV model simplification module, and an optimization module; The conversion module defines the motion coordinate system and the geodetic coordinate system of the tunnel detection AUV according to the operating environment, and obtains the conversion relationship of the coordinate system according to the motion parameters of the tunnel detection AUV; The AUV model simplification module establishes the kinematic model and dynamic model of the tunnel detection AUV according to the data of the conversion module; Simplify the mathematical model of the tunnel detection AUV and perform a force analysis of the tunnel detection AUV; The optimization module uses SOLIDWORKS three-dimensional modeling software to establish a tunnel detection AUV model, check its effectiveness, and repair it if there are problems to complete the optimization of the tunnel detection AUV model.

7. An electronic device, comprising a memory and a processor, the memory storing a computer program, characterized in that, The processor implements the steps of the method according to any one of claims 1 to 5 when executing the computer program.

8. A computer-readable storage medium for storing computer instructions, characterized in that, The computer instructions implement the steps of the method according to any one of claims 1 to 5 when executed by the processor.

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