Truss type net cage control method and device
By establishing a three-dimensional model of the truss-type cage and adjusting the liquid damper using numerical simulation, the problem of poor sway reduction effect of the truss-type cage under severe sea conditions was solved, achieving efficient sway reduction and improved structural stability under different sea conditions.
Patent Information
- Application Number
- CN202511816053.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-04
- Publication Date
- 2026-03-06
AI Technical Summary
Existing truss-type cages have limited sway reduction effect in severe sea conditions, and existing tuned liquid damping systems are costly and their effectiveness depends on a fixed period, making them unable to adapt to changes in wave cycle.
By acquiring the geometric parameters of the truss-type cage, a three-dimensional model is established and numerical simulation is performed. Combining the force field, flow field, and six-degree-of-freedom motion equations, the liquid filling height and damping adjustment coefficient of the liquid damper are adjusted in real time to achieve matching between the damper and the motion state of the cage, thereby dissipating vibration energy.
It improves the sway reduction effect of truss-type cages under different sea conditions, enhances the stability and safety of the structure, and reduces costs.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of marine engineering and aquaculture equipment technology, and in particular to a control method and device for a truss-type net cage. Background Technology
[0002] With limited space available for nearshore aquaculture, marine aquaculture is gradually moving towards the deep sea. As equipment for deep-sea aquaculture, the structural safety and stability of truss-type net cages under complex environmental loads such as wind, waves, and currents are crucial. In severe sea conditions, waves can cause the net cages to sway violently, threatening structural safety. To suppress swaying, tuned liquid damper technology is introduced, utilizing the sloshing of liquid filling the truss-type net cage's floats to dissipate energy and achieve sway reduction.
[0003] In related technologies, passive tuned fluid damping is typically tuned to only a fixed natural period, while the wave period in actual sea conditions is constantly changing. Existing sway reduction techniques (such as adding weight or changing the shape) are costly and have limited effectiveness. The sway reduction effect of a tuned fluid damping system is highly dependent on internal fluid sloshing, energy dissipation, and coupling with the structure.
[0004] Based on this, the present invention proposes a control method and device for truss-type cages to solve the above-mentioned technical problems. Summary of the Invention
[0005] This invention describes a control method and device for truss-type cages, which can improve the sway reduction effect of truss-type cages.
[0006] According to a first aspect, the present invention provides a control method for a truss-type cage, the method comprising: Obtain the geometric parameters of the truss-type cage; Based on the aforementioned geometric parameters, a three-dimensional model of the truss-type cage is determined; The computational domain is established using the three-dimensional model and meshed to obtain a numerical model of the truss-type cage after meshing. The truss-type cage numerical model and simulation equations after meshing are used to perform simulation to determine the motion response of the truss-type cage; wherein, the motion response includes motion direction and motion time; the simulation equations include force field simulation equations, flow field simulation equations, six-degree-of-freedom motion simulation equations of the floating body, and mooring force simulation equations; Based on the motion response, the liquid damper within the truss-type cage structure is controlled.
[0007] According to a second aspect, the present invention provides a control device for a truss-type cage, comprising: The acquisition unit is configured to acquire the geometric parameters of the truss cage; The first data processing unit is configured to determine a three-dimensional model of the truss-type cage based on the geometric parameters. The second data processing unit is configured to use the three-dimensional model to establish a computational domain and perform mesh division to obtain a truss cage numerical model after mesh division. The third data processing unit is configured to perform simulation using the numerical model and simulation equations of the truss-type cage after meshing, and to determine the motion response of the truss-type cage; wherein, the motion response includes the motion direction and motion time; the simulation equations include force field simulation equations, internal flow field simulation equations, external flow field simulation equations, six-degree-of-freedom motion simulation equations of the floating body, and mooring force simulation equations. The fourth data processing unit is configured to control the liquid damper within the truss-type cage structure based on the motion response.
[0008] Thirdly, embodiments of this specification also provide an electronic device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, it implements the method described in any embodiment of this specification.
[0009] Fourthly, embodiments of this specification also provide a computer-readable storage medium having a computer program stored thereon, which, when executed in a computer, causes the computer to perform the methods described in any embodiment of this specification.
[0010] According to the control method and apparatus for the truss-type cage provided by the present invention, the geometric parameters of the truss-type cage are obtained, including the diameter, length, and wall thickness of the pontoons, the cross-sectional dimensions, spacing, and connection method of the truss members, and data such as the anchoring point positions and cable spacing of the mooring system. Based on the above geometric parameters, a full-size three-dimensional solid model of the truss-type cage is constructed using three-dimensional modeling software (such as ANSYS or ABAQUS). Using this three-dimensional model, a computational domain including the cage structure domain and the surrounding fluid domain is divided in the fluid simulation module. The structure domain is divided using a solid mesh, while the fluid domain is divided using an unstructured mesh according to the flow field characteristics. The numerical model was substituted into a multi-field coupled simulation system, combining force field simulation equations, flow field simulation equations (describing the interaction between fluid motion and structure), six-degree-of-freedom motion simulation equations of the floating body (calculating the roll, pitch, and other motion states of the cage), and mooring force simulation equations (simulating changes in cable tension) for simulation. Real-time motion responses of the truss-type cage under different sea conditions were obtained, including motion direction (e.g., horizontal and vertical) and motion time (e.g., vibration period and peak response duration). Finally, based on the obtained motion response data, the real-time matching of the damper and the cage's motion state was achieved by controlling and adjusting the liquid filling height and damping adjustment coefficient of the liquid damper within the truss-type cage structure. This effectively dissipates the cage's vibration energy and improves the sway reduction effect of the truss-type cage. Attached Figure Description
[0011] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0012] Figure 1 A flowchart illustrating a control method for a truss-type cage according to one embodiment is shown; Figure 2 A schematic block diagram of a control device for a truss-type cage is shown according to one embodiment; Figure 3 A structural schematic diagram of a truss-type wire mesh cage according to one embodiment is shown; Figure 4 A schematic diagram of the structure of the pontoon of a truss-type cage according to one embodiment is shown. Detailed Implementation
[0013] The solution provided by the present invention will now be described with reference to the accompanying drawings.
[0014] Figure 1A flowchart illustrating a control method for a truss-type cage according to one embodiment is shown. It is understood that this method can be executed by any device, equipment, platform, or cluster of devices with computing and processing capabilities. Figure 1 As shown, the method includes: Step 100: Obtain the geometric parameters of the truss-type cage; Step 102: Determine the three-dimensional model of the truss-type cage based on geometric parameters; Step 104: Establish the computational domain using the 3D model and perform mesh generation to obtain the numerical model of the truss-type wire mesh cage after mesh generation; Step 106: Perform simulation using the numerical model and simulation equations of the truss-type cage after meshing to determine the motion response of the truss-type cage; the motion response includes the motion direction and motion time; the simulation equations include the force field simulation equation, the flow field simulation equation, the six-degree-of-freedom motion simulation equation of the floating body, and the mooring force simulation equation. Step 108: Based on the motion response, control the liquid damper in the truss-type cage structure.
[0015] In this embodiment, the geometric parameters of the truss-type cage are obtained, including the diameter, length, and wall thickness of the buoys, the cross-sectional dimensions, spacing, and connection methods of the truss members, as well as the anchoring point locations and cable spacing of the mooring system. Based on the above geometric parameters, a full-size three-dimensional solid model of the truss-type cage is constructed using three-dimensional modeling software (such as ANSYS or ABAQUS). Using this three-dimensional model, a computational domain containing the cage's structural domain and the surrounding fluid domain is divided in the fluid simulation module. The structural domain is divided using a solid mesh, while the fluid domain is divided using an unstructured mesh based on the flow field characteristics. This numerical model is then substituted into a multi-field coupled simulation system, combining force field simulation equations, flow field simulation equations (describing the interaction between fluid motion and structure), six-degree-of-freedom motion simulation equations of the floating body (calculating the cage's roll, pitch, and other motion states), and mooring force simulation equations (simulating cable tension changes) for simulation. The motion response of the truss-type cage under different sea conditions is obtained in real time, where the motion response includes the motion direction (e.g., horizontal transverse, vertical longitudinal) and motion time (e.g., vibration period, peak response duration). Finally, based on the acquired motion response data, the real-time matching between the damper and the motion state of the gabion is achieved by controlling and adjusting the liquid filling height and damping adjustment coefficient of the liquid damper in the truss gabion structure, effectively dissipating the vibration energy of the gabion and improving the sway reduction effect of the truss gabion.
[0016] In one embodiment of the present invention, the six-degree-of-freedom motion simulation equations of the floating body are constructed by the following formula:
[0017] In the formula, For rigid body mass, For the acceleration of the center of mass, The total hydrodynamic force exerted on the structure by the fluid. Additional external forces such as gravity, mooring force, and external driving force. For a wet surface that changes over time, It is the normal unit vector pointing towards the fluid side. For viscous stress tensor, Let be the inertia matrix of the rigid body in the current configuration. It is the angular velocity vector. Angular acceleration, For hydrodynamic torque, Let be the position vector from the center of mass to the force-bearing surface element. For other external torques, The excitation torque generated by the external flow field, Pressure calculated for the external wave field. Shear stress calculated for the external wave field. This refers to the wet surface of the truss-type cage that comes into contact with external waves. Let the lever arm be the force pointing from the center of gravity to the point on the surface. The torque exerted by the liquid on the inside of the float. The pressure generated by the liquid damping. This refers to the shear force generated by liquid damping.
[0018] In this embodiment, the excitation torque generated by the external flow field is produced by the impact of waves outside the object. It is obtained by integrating the pressure and shear stress calculated using waves onto the wetted surface of the object. The torque applied by the liquid to the inside of the pontoon: This torque takes into account the damping effect caused by the sloshing of liquid (such as ballast water) that may be present inside the pontoon during its movement. It is obtained by integrating the pressure and shear stress generated by liquid damping onto the surface inside the pontoon that is in contact with the liquid.
[0019] In one embodiment of the present invention, the flow field simulation equation is constructed using the following formula:
[0020] In the formula, This represents the volume fraction of water. The velocity vector of the fluid. It is a divergence operator.
[0021] In one embodiment of the present invention, the flow field simulation equation is optimized using the following formula:
[0022] In the formula, For the second standardized face value, As the first standardized face value, To standardize the grid cell values, The first preset threshold, The second preset threshold, These are the parameters of the dependent variable.
[0023] In this embodiment, the present invention employs a high-resolution interface capture (HRIC) format to simulate the convective transport of immiscible fluid components, thereby generating a format suitable for tracking sharp interfaces, the second normalized surface value. The calculation is as follows:
[0024] Further calculations based on local Courant numbers value:
[0025] in, Indicates fluid on the mesh cell surface The velocity vector at that point, Represents the mesh cell surface The area vector, Indicates the time step. This represents the cell volume. This correction takes into account the availability condition. This condition states that, during a given time step, the amount of one type of fluid convecting across the entire grid cell face is always less than or equal to the amount available in the donor grid cell. This correction is made based on the following expression:
[0026] and The default values are 0.5 and 1, respectively. They are introduced to control the mixing of HRIC and the first-order upwind scheme based on the Courant number. When HRIC will be used when At that time, a mixture of HRIC and first-order upwind patterns will be used. In this case, a first-order upwind scheme will be used. Hybridization will be introduced when the free surface shape exhibits significant temporal variations and its details cannot be solved due to excessively large time steps. This provides stability and reliability to the scheme.
[0027] In one embodiment of the present invention, the mooring force simulation equation is constructed by the following formula:
[0028] In the formula, For mooring pull, For the first The force vector exerted by the catenary at the cable guide hole. For mooring torque, No. The position vector of the cable guide hole of the catenary in the global coordinate system. Let be the position vector of the center of gravity of the rigid body. This refers to the horizontal span between the cable guide hole and the anchor point. The horizontal tension of the catenary. The weight per unit length of the catenary in water. This is the vertical distance between the cable guide hole and the anchor point. This is the length of the catenary after stretching. It is the length of the catenary in the suspended section.
[0029] In one embodiment of the present invention, the force field simulation equations are constructed using the following formula:
[0030] In the formula, Wave height is a wave parameter. For a period of time, The density of seawater, It is the acceleration due to gravity. It is wave force.
[0031] In one embodiment of the present invention, the liquid damping mass in the geometric parameters is determined by the following formula:
[0032] In the formula, Let be the relative acceleration of the liquid surface in fluid damping. Let be the relative velocity of the liquid surface. The damping coefficient is... The effective length for shaking the liquid. The vertical height of the liquid column. Let be the horizontal cross-sectional area of the liquid. The area of the porous medium plate inside the float. The natural frequency of liquid sloshing. This represents the relative displacement of the liquid surface. For externally stimulated acceleration, It is the acceleration due to gravity. For liquid damping mass, The density is the liquid density.
[0033] In this embodiment, the relative acceleration of the liquid surface in the liquid damping is used to control the rate of change of the liquid surface sloshing. Damping term: This is the part that consumes energy and suppresses sloshing. The acceleration of the external excitation is the acceleration generated by the buoy itself due to the wave action; it is this external force that pushes the liquid to start sloshing.
[0034] like Figure 3 As shown, in this embodiment, the entire cage body 1 and four mooring cables 2 are connected to anchor points on the seabed, forming a catenary mooring system to secure it in the designated aquaculture area. It also includes a data acquisition unit 4 and a signal processing module 3. The signal processing module is connected to a motor and can control the water pumps in real time. The truss-type cage body 1 mainly consists of upper horizontal connecting rods 5, middle horizontal connecting rods 7, outer columns 8, upper central column 6, middle central column 9, and bottom floats 11, connected by welding or flanges to form a stable frame structure. Four water pumps are installed inside the middle central column 9, and the pump motors are controlled by the signal processing module 3. A central ballast tank 10 is located at the center of the structure. The ballast tank is filled with water, which is circulated between the water pumps and the outer columns to ensure that the overall mass and draft of the structure remain constant.
[0035] like Figure 4 As shown, in this embodiment, the pontoon is configured as a hollow space, and multiple flexible nets 12 and flexible nets 13 are arranged inside the bottom horizontal pontoon and the outer column.
[0036] The foregoing has described specific embodiments of the invention. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps described in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired results. Furthermore, the processes depicted in the drawings do not necessarily require the specific or sequential order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.
[0037] According to another embodiment, the present invention provides a control device for a truss-type cage. Figure 2 A schematic block diagram of a control device for a truss-type cage is shown according to one embodiment. It will be understood that this device can be implemented by any device, apparatus, platform, or cluster of devices with computing and processing capabilities. Figure 2 As shown, the device includes: an acquisition unit 200, a first data processing unit 202, a second data processing unit 204, a third data processing unit 206, and a fourth data processing unit 208. The main functions of each component are as follows: Acquisition unit 200 is configured to acquire the geometric parameters of the truss cage; The first data processing unit 202 is configured to determine a three-dimensional model of the truss cage based on the geometric parameters. The second data processing unit 204 is configured to use the three-dimensional model to establish a computational domain and perform mesh division to obtain a truss cage numerical model after mesh division. The third data processing unit 206 is configured to perform simulation using the numerical model and simulation equations of the truss-type cage after meshing, and to determine the motion response of the truss-type cage; wherein, the motion response includes the motion direction and motion time; the simulation equations include force field simulation equations, internal flow field simulation equations, external flow field simulation equations, six-degree-of-freedom motion simulation equations of the floating body, and mooring force simulation equations. The fourth data processing unit 208 is configured to control the liquid damper within the truss-type cage structure based on the motion response.
[0038] In one embodiment of the present invention, the six-degree-of-freedom motion simulation equations of the floating body are constructed by the following formula:
[0039] In the formula, For rigid body mass, For the acceleration of the center of mass, The total hydrodynamic force exerted on the structure by the fluid. Additional external forces such as gravity, mooring force, and external driving force. For a wet surface that changes over time, It is the normal unit vector pointing towards the fluid side. For viscous stress tensor, Let be the inertia matrix of the rigid body in the current configuration. It is the angular velocity vector. Angular acceleration, For hydrodynamic torque, Let be the position vector from the center of mass to the force-bearing surface element. For other external torques, The excitation torque generated by the external flow field, Pressure calculated for the external wave field. Shear stress calculated for the external wave field. This refers to the wet surface of the truss-type cage that comes into contact with external waves. Let the lever arm be the force pointing from the center of gravity to the point on the surface. The torque exerted by the liquid on the inside of the float. The pressure generated by the liquid damping. This refers to the shear force generated by liquid damping.
[0040] In one embodiment of the present invention, the flow field simulation equation is constructed using the following formula:
[0041] In the formula, This represents the volume fraction of water. The velocity vector of the fluid. It is a divergence operator.
[0042] In one embodiment of the present invention, the flow field simulation equation is optimized using the following formula:
[0043] In the formula, For the second standardized face value, As the first standardized face value, To standardize the grid cell values, The first preset threshold, The second preset threshold, These are the parameters of the dependent variable.
[0044] In one embodiment of the present invention, the mooring force simulation equation is constructed by the following formula:
[0045] In the formula, For mooring pull, For the first The force vector exerted by the catenary at the cable guide hole. For mooring torque, No. The position vector of the cable guide hole of the catenary in the global coordinate system. Let be the position vector of the center of gravity of the rigid body. This refers to the horizontal span between the cable guide hole and the anchor point. The horizontal tension of the catenary. The weight per unit length of the catenary in water. This is the vertical distance between the cable guide hole and the anchor point. This is the length of the catenary after stretching. It is the length of the catenary in the suspended section.
[0046] In one embodiment of the present invention, the force field simulation equation is constructed using the following formula:
[0047] In the formula, Wave height is a wave parameter. For a period of time, The density of seawater, It is the acceleration due to gravity. It is wave force.
[0048] In one embodiment of the present invention, the liquid damping mass in the geometric parameters is determined by the following formula:
[0049] In the formula, Let be the relative acceleration of the liquid surface in fluid damping. Let be the relative velocity of the liquid surface. The damping coefficient is... The effective length for shaking the liquid. The vertical height of the liquid column. Let be the horizontal cross-sectional area of the liquid. The area of the porous medium plate inside the float. The natural frequency of liquid sloshing. This represents the relative displacement of the liquid surface. For externally stimulated acceleration, It is the acceleration due to gravity. For liquid damping mass, The density is the liquid density.
[0050] According to another embodiment, a computer-readable storage medium is also provided, on which a computer program is stored, which, when executed in a computer, causes the computer to perform a combination Figure 1 The method described.
[0051] According to another embodiment, an electronic device is also provided, including a memory and a processor, wherein the memory stores executable code, and when the processor executes the executable code, it implements a combination... Figure 1 The method described.
[0052] The various embodiments in this invention are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the apparatus embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.
[0053] Those skilled in the art will recognize that, in one or more of the examples above, the functions described in this invention can be implemented using hardware, software, firmware, or any combination thereof. When implemented in software, these functions can be stored in a computer-readable medium or transmitted as one or more instructions or code on a computer-readable medium.
[0054] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made on the basis of the technical solution of the present invention should be included within the scope of protection of the present invention.
Claims
1. A method of controlling a cage of the truss type, characterized in that, The method comprises: acquiring geometric parameters of the truss cage; determining a three-dimensional model of the truss cage based on the geometric parameters; establishing a calculation domain and performing meshing using the three-dimensional model to obtain a numerical model of the truss cage after meshing; performing simulation using the numerical model of the truss cage after meshing and simulation equations to determine the motion response of the truss cage; wherein the motion response comprises a motion direction and a motion time; the simulation equations comprise force field simulation equations, flow field simulation equations, six-degree-of-freedom motion simulation equations of the floating body, and mooring force simulation equations; controlling the liquid damper in the truss cage structure based on the motion response.
2. The method of claim 1, wherein, The six-degree-of-freedom motion simulation equations of the floating body are constructed by the following formula: where, is the rigid body mass, is the center of mass acceleration, is the total hydrodynamic force acting on the structure by the fluid, is the additional external force such as gravity, mooring force, external driving force, etc. is the wet surface changing with time, is the normal unit vector pointing to the fluid side, is the viscous stress tensor, is the inertia matrix of the rigid body in the current configuration, is the angular velocity vector, is the angular acceleration, is the hydrodynamic moment, is the position vector from the center of mass to the force surface element, is the other external moment, is the excitation moment generated by the external flow field, is the pressure calculated from the external wave field, is the shear stress calculated from the external wave field, is the wet surface of the truss cage in contact with the external wave, is the force arm from the center of gravity to the surface point, is the moment applied by the liquid to the inside of the buoy, is the pressure generated by the liquid damping, is the shear force generated by the liquid damping.
3. The method of claim 1, wherein, The flow field simulation equations are constructed by the following formula: wherein is the volume fraction of water, is the velocity vector of the fluid, is the divergence operator.
4. The method of claim 3, wherein, The flow field simulation equations are optimized by the following formula: In the formula, is a second normalized face value, is a first normalized face value, is a normalized grid cell value, is a first preset threshold value, is a second preset threshold value, is a dependent variable parameter.
5. The method of claim 1, wherein, The mooring force simulation equations are constructed by the following formula: wherein is the mooring tension, is the is the force vector exerted by the root catenary at the fairlead, is the mooring moment, is the is the position vector of the fairlead of the root catenary in the global coordinate system, is the position vector of the center of gravity of the rigid body, is the horizontal span between the fairlead and the anchor point, is the horizontal tension of the catenary, is the weight per unit length of the catenary in water, is the vertical distance between the fairlead and the anchor point, is the length of the catenary after stretching, is the length of the catenary of the overhang.
6. The method of claim 1, wherein, The force field simulation equations are constructed by the following formula: wherein is the wave height, is the period, is the sea water density, is the gravity acceleration, is the wave force.
7. The method of claim 1, wherein, The liquid damping mass in the geometric parameters is determined by the following formula: wherein, is the relative acceleration of the liquid level in the liquid damper, is the relative velocity of the liquid level, is the damping coefficient, is the effective length of the sloshing liquid, is the vertical liquid column height, is the horizontal cross-sectional area of the liquid, is the area of the porous media plate inside the pontoon, is the natural frequency of the liquid sloshing, is the relative displacement of the liquid level, is the acceleration of the external excitation, is the gravitational acceleration, is the liquid damper mass, is the liquid density.
8. A control device for a net cage of the truss type, characterized in that comprises: an acquisition unit configured to acquire geometric parameters of the truss cage; a first data processing unit configured to determine a three-dimensional model of the truss cage based on the geometric parameters; a second data processing unit configured to establish a calculation domain and perform meshing using the three-dimensional model to obtain a numerical model of the truss cage after meshing; a third data processing unit configured to perform simulation using the numerical model of the truss cage after meshing and simulation equations to determine the motion response of the truss cage; wherein the motion response comprises a motion direction and a motion time; the simulation equations comprise force field simulation equations, internal flow field simulation equations, external flow field simulation equations, six-degree-of-freedom motion simulation equations of the floating body, and mooring force simulation equations; a fourth data processing unit configured to control the liquid damper in the truss cage structure based on the motion response.
9. An electronic device, comprising: comprises a memory and a processor, the memory stores a computer program, and the processor executes the computer program to implement the method of any one of claims 1-7.
10. A computer-readable storage medium, characterized in that, a computer program is stored thereon, and when the computer program is executed in a computer, the computer program causes the computer to execute the method of any one of claims 1-7.