A simulation method and system for simulating the hoisting and lowering of a load by a crane vessel into waves

Abstract

The present invention belongs to the field of the simulation of the entry of a crane vessel into water, and provides a simulation method and system for simulating the lowering of a load by a crane vessel into waves, including determining a simulation area and constructing a numerical tank; discretizing the calculation area by grids and generating a crane vessel and load models; initializing a simulation environment, setting free surface data, simulation initial boundary conditions and wave parameters; in the simulation environment, performing a simulation using a multi-body motion coupled hydrodynamic model, and using the simulated cable length and cable tension as well as the displacement information of the heave and roll of the crane vessel, a heave compensation system controls the release speed of the cable by a winch in the multi-body motion coupled hydrodynamic model to complete the simulation of the lowering of the load by the crane vessel into waves; updating the motion data of the crane vessel and the load according to the simulation results, and updating the calculation area.

Description

Technical Field

[0001] The present invention belongs to the technical field of the simulation of the entry of a crane vessel into water, and particularly relates to a simulation method and system for simulating the lowering of a load by a crane vessel into waves. Background Art

[0002] The statements in this section merely provide background technical information related to the present invention and do not necessarily constitute prior art.

[0003] Using an offshore crane to lower a payload into waves is a key process in the transportation and installation of subsea structures. Due to the six-degree-of-freedom motion (surge, sway, heave, pitch, roll, yaw) of a ship in the marine environment, it is more difficult to hoist with an offshore crane than with an onshore crane, and the payload is lower. Especially during the entry into water, the intense hydrodynamic forces acting on the payload cause large changes in the cable tension, which may result in cable breakage and accidents. Therefore, a numerical model for simulating crane hoisting is required before the start of offshore engineering to evaluate and analyze the operation process of the crane vessel. And for a newly designed crane controller, a near-real offshore engineering environment is also needed for verification.

[0004] Some existing ship-hoisting simulation software estimates the hydrodynamic forces of the load and the crane vessel through simplified formulas, without considering the hydrodynamic influence between the crane vessel and the load. Currently, most of the simulation analysis methods for an offshore crane to lower a load into waves mainly fall into two categories. The first is the method based on empirical formulas to solve the hydrodynamic forces acting on the hull and the load. The hydrodynamic force results obtained by this method are inaccurate and do not consider the interaction between the load and the waves. The second is the method based on computational fluid dynamics. The hydrodynamic force results obtained by this method are accurate, but it does not model the complete crane system and can only simulate the motion of a single load or the hull in waves. Summary of the Invention

[0005] To solve the above problems, the present invention proposes a simulation method and system for simulating the lowering of a load by a crane vessel into waves. The present invention proposes a calculation method for elastic cables, which effectively reduces the energy error of the cable system. In a laboratory environment, a crane model was used to lower an aluminum block into water, and the cable force and motor speed changes were recorded to verify the effectiveness of each module integrated in the numerical model.

[0006] According to some embodiments, the first aspect of the present invention provides a simulation method for simulating the lowering of a load by a crane vessel into waves, adopting the following technical solution:

[0007] A simulation method for simulating the lowering of a load by a crane vessel into waves, comprising:

[0008] Determine the simulation area and construct a numerical water tank;

[0009] Discretize the computational domain by a grid and generate a model of the crane vessel and the load;

[0010] Initialize the simulation environment, set the free surface data, the initial boundary conditions of the simulation, and the wave parameters;

[0011] In the simulation environment, use the multi-body motion coupled hydrodynamic model for simulation. Utilize the simulated cable length, cable tension, and the displacement information of the heave and roll of the crane vessel. The heave compensation system controls the release speed of the cable by the winch in the multi-body motion coupled hydrodynamic model to complete the simulation of the crane vessel lowering the load into the waves;

[0012] Update the motion data of the crane vessel and the load according to the simulation results, and update the computational domain.

[0013] Further, if the simulation time has not reached the set time, enter the next time period and continue the simulation until the simulation time reaches the set time.

[0014] Further, the multi-body motion coupled hydrodynamic model includes a cable module, a winch module, a control system, and a neural network module;

[0015] The cable module is used to provide tension to the load and realizes the lowering and hoisting operations by extending or shortening the length of the cable; the winch module simulates the electric motor winch system in the project and is used to drive the drum to retract and release the cable; the control system integrates the discrete form of the control first-order and second-order inertia links of the linear system and realizes the controller of the linear control system in the model; the neural network module is used to process the model trained based on the Pytorch neural network framework.

[0016] Further, the cable module determines the cable elongation, specifically:

[0017] Δx cable =(x payload +v payload Δt / 2)-(x cable +v cable Δt / 2)+(x vessel +v vessel Δt / 2)

[0018] where v payload 、v cable and v vessel are the velocities of the load, the cable, and the crane vessel respectively, the elongation of the spring is Δx cable , the displacement of the crane vessel is x vessel , the displacement of the load is x payload and the natural length of the cable is x cable .

[0019] Furthermore, in the winch module simulation, the electric motor winch system in the project is simulated, specifically as follows:

[0020] Obtain the mathematical model of the electric motor;

[0021] Perform Laplace transform according to the mathematical model of the electric motor and convert it into the block diagram of the electric motor system;

[0022] The block diagram of the electric motor system is formed by two inertia links connected in series.

[0023] Furthermore, the control system also integrates a discrete tracking differentiator, which is used to obtain a smooth differential signal from a noisy signal and input it to the controller.

[0024] Furthermore, determine the simulation area and construct a numerical water tank, specifically as follows:

[0025] According to the dimensions of the hull and the load, and different wave environment parameters for simulation research, define the dimensions of the simulation area, construct a rectangular numerical water tank, define different boundary conditions on each surface of the numerical water tank, set wave-making boundary conditions at the wave-making boundary, and set the wave height, period, wave type, and wave dissipation method parameters of the wave through a wave configuration file;

[0026] Set the free surface height in the numerical water tank, and lift and sink the structures of the heavy lift vessel and the load;

[0027] Design a grid to discretize the calculation area, discretize the continuous solution domain into several finite sub-regions, solve the variables of each sub-region respectively, and make the adjacent sub-regions continuous and coordinated, so as to achieve the coordination and continuity of the entire variable field.

[0028] According to some embodiments, the second solution of the present invention provides a simulation system for simulating a heavy lift vessel lowering a load into waves, adopting the following technical solution:

[0029] A simulation system for simulating a heavy lift vessel lowering a load into waves, comprising:

[0030] A simulation area determination module, configured to determine the simulation area and construct a numerical water tank;

[0031] A grid discretization module, configured to discretize the calculation area through a grid and generate a heavy lift vessel and load model;

[0032] A simulation environment initialization module, configured to initialize the simulation environment, set free surface data, simulation initial boundary conditions, and wave parameters;

[0033] The simulation module is configured to perform simulations in a simulation environment using a multi-body motion coupled hydrodynamic model. Using the simulated cable length, cable tension, and the displacement information of the heave and roll of the crane vessel, the heave compensation system controls the release speed of the cable by the winch in the multi-body motion coupled hydrodynamic model to complete the simulation of the crane vessel lowering the load into the waves.

[0034] The simulation update module is configured to update the motion data of the crane vessel and the load according to the simulation results and update the calculation area.

[0035] According to some embodiments, a third aspect of the present invention provides a computer-readable storage medium.

[0036] A computer-readable storage medium stores a computer program thereon, and when the program is executed by a processor, it implements the steps in a simulation method for simulating a crane vessel lowering a load into the waves as described in the first aspect above.

[0037] According to some embodiments, a fourth aspect of the present invention provides a computer device.

[0038] A computer device includes a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, it implements the steps in a simulation method for simulating a crane vessel lowering a load into the waves as described in the first aspect above.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0040] Based on OpenFOAM, the present invention proposes a numerical model for simulating a crane lowering a load into water. This model is used to simulate the process of a crane lowering a load into water through a cable in a wave environment. Different from other offshore engineering simulation software, this model is based on fluid mechanics methods and can accurately calculate the hydrodynamic forces on the crane vessel and the load, and can analyze some non-linear phenomena of the crane vessel and the load in water. At the same time, this model combines fluid mechanics with a control system and can simulate the process of the crane vessel's lowering operation under the control of an automatic control system to evaluate the construction risks of crane vessel engineering and verify the effectiveness of the designed crane control system.

[0041] Based on fluid mechanics methods, on the basis of ensuring the accuracy of the hydrodynamic results, the present invention details the modeling of the entire crane vessel system and adds a control module and a neural network module. It can simulate the complete process of a crane vessel lowering a load into water under the control of a heave compensation control system. Description of the Drawings

[0042] The accompanying drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0043] Figure 1 It is a flowchart of a simulation method for simulating the hoisting of a load by a crane ship into waves in an embodiment of the present invention;

[0044] Figure 2 It is a schematic diagram of a numerical wave tank in an embodiment of the present invention;

[0045] Figure 3 It is the verification result of the cable tension optimization algorithm in an embodiment of the present invention;

[0046] Figure 4 It is a block diagram of a motor system in an embodiment of the present invention;

[0047] Figure 5 It is a schematic diagram of numerical simulation and physical experiment in an embodiment of the present invention;

[0048] Figure 6 It is the verification result of the numerical model in an embodiment of the present invention;

[0049] Figure 7 It is a computational domain and grid distribution diagram of the load hoisted by a crane ship into water in an embodiment of the present invention;

[0050] Figure 8 It is the change of the load speed and cable tension during the process of the load being hoisted by a crane ship into water in an embodiment of the present invention;

[0051] Figure 9 It is to consider adding a PID controller during the process of the load being hoisted by a crane ship into waves in an embodiment of the present invention;

[0052] Figure 10 It is the free surface change and velocity distribution during the process of the load being hoisted by a crane ship into water in an embodiment of the present invention;

[0053] Figure 11 It is a schematic diagram of the hull movement of the simulated load in an embodiment of the present invention. Detailed implementation manners

[0054] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0055] It should be noted that the following detailed descriptions are all illustrative and are intended to provide a further description of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0056] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0057] In the case of no conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0058] Embodiment 1

[0059] As Figure 1 shown, this embodiment provides a simulation method for simulating a lifting vessel lowering a load into waves. In this embodiment, the method includes the following steps:

[0060] Determine the simulation area and construct a numerical water tank;

[0061] Discretize the computational domain by grids and generate the models of the lifting vessel and the load;

[0062] Initialize the simulation environment and set the free surface data, the initial simulation boundary conditions, and the wave parameters;

[0063] In the simulation environment, use the multi-body motion coupled hydrodynamic model for simulation. Using the simulated cable length, cable tension, and the displacement information of the heave and roll of the lifting vessel, the heave compensation system controls the release speed of the cable by the winch in the multi-body motion coupled hydrodynamic model to complete the simulation of the lifting vessel lowering the load into waves;

[0064] Update the motion data of the lifting vessel and the load according to the simulation results and update the computational domain.

[0065] Furthermore, if the simulation time has not reached the set time, enter the next time period and continue the simulation until the simulation time reaches the set time.

[0066] Furthermore, the multi-body motion coupled hydrodynamic model includes a cable module, a winch module, a control system, and a neural network module;

[0067] The cable module is used to provide tension to the load and realizes the lowering and lifting operations by extending or shortening the length of the cable; the winch module simulates the electric motor winch system in the project and is used to drive the drum to take in and release the cable; the control system integrates the discrete forms of the control first-order and second-order inertia links of the linear system and realizes the controller of the linear control system in the model; the neural network module is used to process the model trained based on the Pytorch neural network framework.

[0068] Furthermore, the cable module determines the cable elongation amount, specifically as follows:

[0069] Δx cable =(x payload +v payload Δt / 2)-(x cable +v cable Δt / 2)+(x vessel +v vessel Δt / 2)

[0070] wherein, v payload , v cable and v vessel are the speeds of the load, the cable, and the crane vessel respectively, the elongation amount of the spring is Δx cable , the displacement of the crane vessel is x vessel , the displacement of the load is x payload , and the natural length of the cable is x cable .

[0071] Furthermore, the winch module simulates the motor winch system in the project, specifically as follows:

[0072] Obtain the mathematical model of the motor;

[0073] Perform Laplace transform according to the mathematical model of the motor and convert it into a motor system block diagram;

[0074] The motor system block diagram is formed by two inertia links connected in series.

[0075] Furthermore, the control system also integrates a discrete tracking differentiator, which is used to obtain a smooth differential signal from a noisy signal and input it to the controller.

[0076] Determine the simulation area and construct a numerical water tank, specifically as follows:

[0077] According to the dimensions of the hull and the load, and different wave environment parameters for simulation research, define the dimensions of the simulation area, construct a rectangular numerical water tank, define different boundary conditions on each surface of the numerical water tank, set the wave-making boundary conditions at the wave-making boundary, and set the wave height, period, wave type, and wave dissipation method parameters of the wave through the wave profile file;

[0078] Set the free surface height in the numerical water tank, and heave the structures of the crane vessel and the load;

[0079] Design a grid to discretize the calculation area, discretize the continuous solution domain into several finite sub-regions, solve the variables of each sub-region respectively, and make each sub-region adjacent, continuous, and coordinated, so as to achieve the coordination and continuity of the entire variable field.

[0080] Numerical model for simulating a crane dropping a load into water

[0081] Numerical calculation area

[0082] Use the blockMesh toolbox in OpenFOAM to create the calculation area, such as Figure 1 As shown in the figure. The boundary condition on the left is the wave-making boundary condition, which generates different types of waves such as solitary waves, Stokes regular waves, irregular waves, etc. by setting the speed and pressure. The numerical water tank eliminates the reflection of waves by actively eliminating the waves, so as to prevent the reflected waves from colliding with the surrounding walls and affecting the hydrodynamic calculation of the crane and the load.

[0083] like Figure 2 As shown in the figure, a crane ship and a suspended load are generated in the numerical pool. In order to save computing resources, the hull and the load are replaced by squares. In the simulation of the real project, the crane ship and the load can be accurately modeled by modeling software, and then generated into the numerical model using the snappyHexMesh tool provided by OpenFOAM.

[0084] Implementation of the crane module

[0085] In order to simulate the process of crane lifting load through cables, cable module, winch module, control system module and neural network module are established in the numerical model. This section shows the specific implementation details of each module.

[0086] Cable Module

[0087] Since the crane cable is very long, the elasticity of the cable needs to be considered. We simplify the cable as a spring with a natural length that can be extended, and the stiffness k of the lifting spring remains unchanged. Calculate the spring tension F cable The formula is:

[0088] F cable = kΔx cable +C damp Δx cable (1)

[0089] Where Δx cable is the elongation of the spring, C damp is the damping coefficient. During the calculation process, the elongation of the spring Δx cable The displacement of the crane vessel x vessel , displacement of the load x payload and the natural length of the cable x cable Decide:

[0090] Δx cable =x payload -x cable -x vessel(2)

[0091] The displacement x of the crane ship at the initial moment vessel and x payload are 0, and the displacement of the load xpayload is equal to the natural length of the cable.

[0092] Elastic cable tension optimization algorithm:

[0093] At the beginning of each time step, the tension of the cable is calculated to calculate the resultant force on the load. However, in each time step, the tension of the cable remains unchanged, while in reality, the deformation and tension of the cable change at any time. This leads to an error between the energy of the elastic cable system in the discrete model and the actual situation, and the error becomes more obvious as the time step increases. Therefore, for the cable calculation method in formula (2), a new calculation formula for the cable elongation is proposed:

[0094] Δx cable =(x payload +v payload Δt / 2)-(x cable +v cable Δt / 2)+(x vessel +v vessel Δt / 2)(3)

[0095] where v payload 、v cable and v vessel are the velocities of the load, the cable, and the crane ship respectively. We calculate the cable elongation Δx cable as the intermediate quantity between this time step and the next time step. Using this intermediate elongation to calculate the cable tension can effectively reduce the energy error of the cable and the load. As Figure 3 shown, a free oscillation motion of a spring is simulated using the model, and it can be seen that as the time step increases, the amplitudes of the velocity of the load and the tension of the spring become larger and larger. It can be seen that the optimization algorithm can significantly reduce the increase in the amplitudes of the velocity and the tension, and reduce the energy error of the system.

[0096] Electric winch system

[0097] To simulate the process of the crane releasing and retracting the cable in the actual situation, an electric winch system is integrated into the model. The mathematical model of the motor is as follows:

[0098]

[0099]

[0100] where, L a and R a are the inductance and resistance of the motor respectively. Ua is the motor control voltage, I a is the armature current. K T and K e are the motor gain coefficient and the motor back electromotive force coefficient. T L represents torque, J is the moment of inertia, B a is the damping coefficient. θ is the rotation angle of the motor, and the release speed v of the cable can be obtained cable = θR, where R is the radius of the winch drum.

[0101] Then, the mathematical model of the motor is transformed into the form of a system block diagram by Laplace transform, as Figure 4 shown. It can be seen that the motors are connected in series through two inertia links.

[0102] To integrate the motor system into the numerical model, we convert the first-order inertia link in the block diagram into a discrete form:

[0103]

[0104] Through this discrete form, the block diagram of the motor is compiled into the model through C++, and the simulation of different types of motor systems is achieved by adjusting various coefficients.

[0105] Control system

[0106] Most controllers can be implemented in the model. The mathematical equations of the controllers can be discretized and then input into the model. Taking the heave compensation system as an example, a PID controller is integrated in the model to make the speed of the load track the desired speed v desired :

[0107]

[0108] where e(k) is the tracking error of the system. k p , k i , and k d are the proportional, integral, and differential coefficients used to adjust the controller. u c is the obtained control signal used to control the winch system. v desired is the desired speed of the load. If the load is to move at a constant speed during the falling process, then v desired is set to a constant. v payload is the actual speed of the load, which can be measured by the device.

[0109] Generally, the information measured in actual engineering or the data calculated in simulation will have some noise or oscillations. If such noisy data is used, it will cause the control voltage output by the PID controller to be unstable. Therefore, a discrete tracking differentiator is integrated into the numerical model to obtain smooth differential data from the noisy data:

[0110]

[0111] where \(x\) 1 is the tracking data, and \(x\) 2 is the differential data obtained by tracking. Among them, the functions Sat(·,δ) and g(·) are respectively:

[0112]

[0113]

[0114] where \(r\) is the acceleration coefficient, \(h\) 1 and δ are filtering coefficients. \(e(k)=x\) 1 (k) - x payload (k) is the tracking error.

[0115] Neural network module

[0116] The model integrates the Pytorch C++ library and can load neural network models based on the Pytorch framework. This model has written a neural network interface, and the trained model can be placed in the case folder to use the neural network by setting the input information and output information of the network.

[0117] Model verification

[0118] Through the process of the crane physical platform lifting and lowering the load into the water, the correctness of each module proposed above is verified. First, use the crane platform to lower an aluminum block into the pool and record the changes in the cable tension and motor speed during the lifting and lowering process. Then use the proposed numerical model for simulation, as Figure 5 shown.

[0119] Then, by comparing the changes in cable tension and motor speed between the numerical simulation and the physical experiment, the correctness of the proposed numerical model is verified. As Figure 6 shown, it can be seen that the results obtained from the simulation experiment are basically consistent with the experimental results, and the accuracy of each module in the numerical model is verified.

[0120] Research on the problem of a crane ship lifting and lowering a load into the water

[0121] The process of a crane ship lowering a load into waves was studied using a numerical model. By calculating the changes in cable tension and the load movement speed, the influence of the heave motion of the crane ship on the hoisting process was analyzed. The computational domain and grid distribution for the numerical simulation are as shown in Figure 7 Figure [1]. The length of the numerical wave tank for the simulation is 6.5 m, the width is 1 m, and the water depth is 0.6 m. The crane ship is placed in the middle of the tank with a length of 0.8 m, a width of 0.3 m, and a draft of 0.2 m. The load has a length, width, and height of 0.2 m each, and is suspended 0.25 m in front of the crane ship and 0.2 m away from the free surface. The computational domain is discretized using hexahedral meshes, and the meshes are refined in the wave generation area, the crane ship - load area, and near the free liquid surface to improve the calculation accuracy.

[0122] As shown in Figure 8 Figure [2], the numerical model proposed in this paper was used to simulate the process of a crane ship lowering a load into waves, and data on the cable tension and load movement varying with time were obtained. The cases with and without the influence of the heave motion of the crane ship were discussed separately. The load entering the water was divided into three stages: the air stage, the water - entry stage, and the submerged stage. It can be seen that when considering the influence of the crane ship on the load, the movement amplitude of the load increases significantly due to the heave motion of the crane ship, and the amplitude of the cable tension also becomes larger. This indicates that the motion of the crane ship will increase the water - entry speed of the load, leading to a greater hydrodynamic impact, and the increase in the dynamic tension of the cable will also pose a risk of cable breakage. It can be seen that the maximum tension of the cable appears at the initial stage of water entry. During the water - entry stage, due to the compensation effect of the waves, both the water - entry speed of the load and the dynamic tension of the cable decrease. However, during the submerged stage, the load speed and the dynamic tension of the cable increase again.

[0123] Then, a controller was added to the model simulation. A PID controller was used to adjust the speed of the winch releasing the cable to achieve a uniform water entry of the load. As shown in Figure 9 Figure [3], by adjusting the speed of the winch releasing the cable, the load speed is basically stabilized at 0.1 m / s. Moreover, the dynamic tension of the cable also decreases.

[0124] Since the numerical model of the present invention is proposed based on the CFD framework, the calculated hydrodynamic data are very accurate, and the distribution data of the free liquid surface can also be obtained. As shown in Figure 10 Figure [4], the shape change of the free liquid surface and its velocity distribution can be seen.

[0125] The present invention can simulate hulls and loads of any shape. Through the snappyHexMesh tool, any three - dimensional model can be generated into the model proposed in the present invention, as shown in Figure 11 Figure [5].

[0126] Embodiment 2

[0127] This embodiment provides a simulation system for simulating a lifting vessel lowering a load into waves, including:

[0128] A simulation area determination module, configured to determine a simulation area and construct a numerical tank;

[0129] A grid discretization module, configured to discretize the calculation area through a grid and generate a lifting vessel and load model;

[0130] A simulation environment initialization module, configured to initialize the simulation environment, set free surface data, simulation initial boundary conditions, and wave parameters;

[0131] A simulation module, configured to perform simulation in the simulation environment using a multi-body motion coupled hydrodynamic model, and use the simulated cable length, cable tension, and the displacement information of the heave and roll of the lifting vessel. The heave compensation system controls the release speed of the cable by the winch in the multi-body motion coupled hydrodynamic model to complete the simulation of the lifting vessel lowering the load into waves;

[0132] A simulation update module, configured to update the motion data of the lifting vessel and the load according to the simulation results and update the calculation area.

[0133] The examples and application scenarios implemented by the above modules and the corresponding steps are the same, but are not limited to the content disclosed in the first embodiment above. It should be noted that the above modules, as part of the system, can be executed in a computer system such as a set of computer executable instructions.

[0134] In the above embodiments, the descriptions of each embodiment have their own emphases. For parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0135] The proposed system can be implemented in other ways. For example, the system embodiments described above are only illustrative. For example, the division of the above modules is only a logical function division. In actual implementation, there can be other division methods. For example, multiple modules can be combined or integrated into another system, or some features can be ignored or not executed.

[0136] Embodiment Three

[0137] This embodiment provides a computer-readable storage medium, on which a computer program is stored. When the program is executed by a processor, it implements the steps in a simulation method for simulating a lifting vessel lowering a load into waves as described in the first embodiment above.

[0138] Embodiment Four

[0139] This embodiment provides a computer device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, it implements the steps in a simulation method for simulating a crane ship hoisting a load into waves as described in Embodiment 1 above.

[0140] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of a hardware embodiment, a software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memories and optical memories, etc.) containing computer-usable program code.

[0141] The present invention is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to the embodiments of the present invention. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, as well as the combination of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0142] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory generate a manufactured article including instruction means, and the instruction means implements the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0143] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process. Thus, the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0144] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above methods. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM), etc.

[0145] Although the specific implementation manners of the present invention have been described above in conjunction with the accompanying drawings, it is not a limitation on the protection scope of the present invention. Those skilled in the art should understand that based on the technical solutions of the present invention, various modifications or deformations that can be made by those skilled in the art without creative efforts are still within the protection scope of the present invention.

Claims

1. A simulation method for simulating a lifting vessel lowering a load into waves, characterized in that, it includes: Determine the simulation area and construct a numerical tank; Discretize the computational domain through meshing and generate models of the lifting vessel and the load; Initialize the simulation environment, set free surface data, simulation initial boundary conditions, and wave parameters; In the simulation environment, use a multi-body motion coupled hydrodynamic model for simulation. Utilize the simulated cable length, cable tension, and the displacement information of the heave and roll of the lifting vessel. The heave compensation system controls the release speed of the cable by the winch in the multi-body motion coupled hydrodynamic model to complete the simulation of the lifting vessel lowering the load into waves; The multi-body motion coupled hydrodynamic model includes a cable module, a winch module, a control system, and a neural network module; The cable module is used to provide tension to the load and realizes lowering and lifting operations by elongating or shortening the length of the cable; the winch module simulates the electric motor winch system in engineering and is used to drive the drum to retract and release the cable; the control system integrates the discrete forms of the control first-order and second-order inertia links of the linear system and realizes the controller of the linear control system in the model; the neural network module is used to process the model trained based on the Pytorch neural network framework; Update the motion data of the lifting vessel and the load according to the simulation results and update the computational domain.

2. A simulation method for simulating a lifting vessel lowering a load into waves according to claim 1, characterized in that, If the simulation time has not reached the set time, enter the next time period and continue the simulation until the simulation time reaches the set time.

3. A simulation method for simulating a lifting vessel lowering a load into waves according to claim 1, characterized in that, The cable module determines the cable elongation amount, specifically: ； Among them, , and are the speeds of the load, the cable, and the crane ship respectively, the elongation of the spring , the displacement of the crane ship , the displacement of the load and the natural length of the cable .

4. A simulation method for simulating a lifting vessel lowering a load into waves according to claim 1, characterized in that, The winch module simulates the electric motor winch system in engineering, specifically: Obtain the mathematical model of the electric motor; Perform Laplace transform according to the mathematical model of the electric motor and convert it into the block diagram of the electric motor system; The block diagram of the electric motor system is formed by two inertia links connected in series.

5. A simulation method for simulating a lifting vessel lowering a load into waves according to claim 1, characterized in that, The control system also integrates a discrete tracking differentiator, and the tracking differentiator is used to obtain a smooth differential signal from the noisy signal and input it to the controller.

6. A simulation method for simulating a lifting vessel lowering a load into waves according to claim 1, characterized in that, Determine the simulation area and construct a numerical tank, specifically: According to the dimensions of the hull and the load and different wave environment parameters for simulation research, define the dimensions of the simulation area, construct a rectangular numerical tank, define different boundary conditions on each surface of the numerical tank, set the wave-making boundary condition at the wave-making boundary, and set the wave height, period, wave type, and wave dissipation method parameters of the wave through the wave configuration file; Set the free surface height in the numerical tank and heave the structures of the lifting vessel and the load; The design grid discretizes the computational domain, divides the continuous solution domain into several finite sub-regions, solves the variables of each sub-region separately, and makes the adjacent sub-regions continuous and coordinated, so as to achieve the coordination and continuity of the entire variable field.

7. A simulation system for simulating a crane vessel lowering a load into waves, characterized in that, it includes: A simulation area determination module, configured to determine a simulation area and construct a numerical water tank; A grid discretization module, configured to discretize the computational area through a grid and generate a crane vessel and load model; A simulation environment initialization module, configured to initialize the simulation environment, set free surface data, simulation initial boundary conditions, and wave parameters; A simulation module, configured to perform a simulation in the simulation environment using a multi-body motion coupled hydrodynamic model, and use the simulated cable length and cable tension, as well as the displacement information of the heave and roll of the crane vessel, and the heave compensation system controls the release speed of the cable by the winch in the multi-body motion coupled hydrodynamic model to complete the simulation of the crane vessel lowering a load into waves; The multi-body motion coupled hydrodynamic model includes a cable module, a winch module, a control system, and a neural network module; The cable module is used to provide tension to the load and realizes lowering and lifting operations by extending or shortening the length of the cable; the winch module simulates the motor winch system in the project and is used to drive the drum to retract and release the cable; the control system integrates the discrete form of the control first-order and second-order inertia links of the linear system and realizes the controller of the linear control system in the model; the neural network module is used to process the model trained based on the Pytorch neural network framework; A simulation update module, configured to update the motion data of the crane vessel and the load according to the simulation results, and update the computational area.

8. A computer-readable storage medium, on which a computer program is stored, characterized in that, when the program is executed by a processor, it implements the steps in a simulation method for simulating a crane vessel lowering a load into waves according to any one of claims 1-6.

9. A computer device, including a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, when the processor executes the program, it implements the steps in a simulation method for simulating a crane vessel lowering a load into waves according to any one of claims 1-6.

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