Dynamic performance display method of boom based on model reduction and digital twin

Abstract

The present invention provides a boom dynamic performance display method based on model reduction and digital twinning, comprising: constructing a finite element mesh model according to the three-dimensional model of the boom, extracting characteristic information of the finite element mesh model and reconstructing the finite element mesh model; constructing a proxy model of dynamic parameters and reduced low-dimensional data features, and calculating the predicted stress values ​​of all nodes of the finite element mesh model through the proxy model; obtaining the motion base points of different components in the finite element mesh model, and establishing a spatial motion function module of the finite element mesh model in the VTK module; assigning the stress value to the node color rendering value based on the VTK module and updating it to the finite element mesh model in real time; and publishing the processed finite element mesh model through the system. The boom dynamic performance display method provided by the present invention can intuitively display the maximum stress and stress concentration parts of the boom, thereby realizing dynamic, fast and efficient boom structure design.

Description

Technical Field

[0001] The present invention relates to the field of digital twin technology, and in particular to a method for displaying the dynamic performance of an arm based on model order reduction and digital twin. Background Art

[0002] A drilling rig is a type of rock drilling equipment that uses the drill-and-blast method for tunnel and underground engineering construction. It can move and support multiple rock drills to perform drilling operations simultaneously. The rock drills are fixed to the outer end of the trolley boom and rely on the boom to complete rotation, translation and other movements during operation. In the development of digital twin technology for drilling rigs, the "virtual-real synchronization" technology of actual trolley equipment operation and virtual trolley equipment has attracted widespread attention, among which real-time simulation technology is the most critical link in achieving virtual-real synchronization. At present, the design of trolley equipment mostly relies on empirical design, and the strength verification in the design process is often completed using large-scale finite element simulation software, and the results are displayed through post-processing finite element software. Although a complete design and simulation process has been formed in the engineering machinery industry, the traditional design and simulation process has the following problems under the requirements of the "virtual-real synchronization" technology of digital twins:

[0003] First, the working conditions of a drilling rig are constantly changing during operation. When drilling, different drilling positions require the boom to have different postures, so the stress conditions of the boom structure should change in real time with the change in posture. Traditional simulation processes require setting boundary conditions for the model, and the boundary conditions set for different postures of the rig should also be different. However, for complex underground engineering equipment such as drilling rigs, the number of grids in their finite element models is often over one million, and the time required to iterate the differential equations of the finite element model is long. When the boom's posture changes, the boundary conditions of the finite element model need to be reset. Coupled with the subsequent long solution process, the manpower, time and other costs required for the process increase dramatically.

[0004] Secondly, the existing software's corresponding analysis results (arm force and impact force) under different working conditions (boundary conditions) are independent, and it is impossible to display the overall force and deformation result cloud map of the finite element model under different working conditions, that is, within the boundary condition parameter range. It cannot meet the array twin "virtual and real synchronization" technology requirement that the virtual body be displayed synchronously with the physical body.

[0005] In addition, the result files of the finite element model are mainly large data files (ODB) files, which contain a large amount of data information and rely on the iterative solution of differential equations, which requires a long solution time.

[0006] Finally, even if the data scale problem of the model result file is solved, the existing technology cannot present the stress state of the boom in different postures and different force conditions as a whole. Therefore, it is necessary to establish a virtual body of the physical boom structure to synchronously and coordinately display and obtain an intuitive and visual three-dimensional model of the boom in different working conditions.

[0007] The above are all difficulties in applying digital twin technology to drilling rigs. Existing technical solutions and means are difficult to truly achieve the synchronous mapping between the actual physical prototype status of the drilling rig equipment and the virtual model prototype status.

[0008] In summary, there is an urgent need for a boom dynamic performance display method based on model reduction and digital twin to solve the problems existing in the existing technology. Summary of the Invention

[0009] The purpose of this invention is to provide a boom dynamic performance display method based on model reduction and digital twinning. The specific technical solution is as follows:

[0010] A boom dynamic performance display method based on model order reduction and digital twinning is characterized by comprising:

[0011] S1: Construct a finite element mesh model based on the three-dimensional model of the boom, extract the characteristic information of the finite element mesh model and reconstruct the finite element mesh model;

[0012] S2: Construct a proxy model of dynamic parameters and reduced low-dimensional data features, and calculate the predicted stress values ​​of all nodes of the finite element mesh model through the proxy model;

[0013] S3: Obtain the motion base points of different components in the finite element mesh model and establish the spatial motion function module of the finite element mesh model in the VTK module;

[0014] S4: Based on the VTK module, the stress value is assigned to the node color rendering value and updated to the finite element mesh model in real time; the processed finite element mesh model is published through the system to realize the dynamic performance display of the boom.

[0015] Preferably, the characteristic information of the finite element mesh model includes node coordinate information, unit number information and included node number information.

[0016] Preferably, reconstructing the finite element mesh model includes: through the patch function in the VTK module, based on the corresponding node number information and node coordinate information of the finite element model units in the extracted finite element mesh model, realizing the reconstruction of the finite element model units from points to surfaces to bodies, and sequentially reconstructing the extracted single finite element model units according to the extracted unit number information.

[0017] Preferably, the proxy model construction step includes: obtaining multiple groups of simulation sample data, selecting sample data points within the dynamic parameter value range as input dynamic parameters, calculating the stress values ​​corresponding to the sample points of the finite element mesh model through finite element analysis software, and reducing the stress values ​​to obtain the sample low-dimensional data features output by the proxy model, and constructing a proxy model of the dynamic parameters and the reduced low-dimensional data features through interpolation method.

[0018] Preferably, the stress value reduction process is to reduce the stress value by an intrinsic orthogonal decomposition method.

[0019] Preferably, the construction of the spatial motion function module specifically includes: selecting a set of simulation sample data as the initial working condition of the finite element mesh model and setting its initial posture state; obtaining the motion base points of different components in the finite element mesh model; establishing a motion relationship between dynamic parameters and component nodes, and writing a script program based on the motion units and node spatial coordinate changes of the finite element mesh model components to obtain the spatial motion function module.

[0020] Preferably, the motion base point includes a finite element mesh model component and its coordinate position.

[0021] Preferably, the step S4 is specifically as follows: based on the color rendering mapping mechanism of the VTK module, the stress value is equivalently converted into RBG color mode data, and the node color representing the stress value of the finite element mesh model node is assigned. The interpolation method of the VTK module completes the stress color rendering mapping from point to line and line to surface and updates it to the finite element mesh model in real time; the processed finite element mesh model is published through the system to realize the dynamic performance display of the boom.

[0022] The application of the technical solution of the present invention has the following beneficial effects:

[0023] The present invention provides a boom dynamic performance display method based on model reduction and digital twinning. By establishing and reconstructing a finite element mesh model, the proxy model of the node stress value obtained in step S2 can realize the update of the node stress value based on dynamic parameters in the finite element mesh model, and step S3 completes the dynamic update of the spatial posture of the finite element mesh model based on dynamic parameters. Finally, through the VTK module rendering, when the posture of the finite element mesh model changes, the node coordinate information is updated and the change of the node stress value is displayed. The maximum stress and stress concentration parts of the boom are intuitively displayed. The weak parts of the structure are analyzed and reconstructed in the design stage, so that the designed boom structure can meet the structural strength requirements corresponding to all postures during work, and realize dynamic, fast and efficient boom structure design.

[0024] In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0026] Figure 1 Schematic diagram of the process of the boom dynamic performance display method in the preferred embodiment 1 of the present invention;

[0027] Figure 2 Schematic diagram of the structure of the finite element mesh model of the two-section boom in the preferred embodiment 1 of the present invention;

[0028] Figure 3 yes Figure 2 Simplified geometric diagram of the middle oil cylinder;

[0029] Figure 4 Schematic diagram of the dynamic model of the two-section boom in the VTK module of the present invention;

[0030] Among them, 1-arm one, 2-rotating shaft one, 3-arm two, 4-rotating shaft two, 5-cylinder body, 6-cylinder piston rod, 7-rotating shaft three. DETAILED DESCRIPTION

[0031] To facilitate understanding of the present invention, the present invention will be described more fully below, along with preferred embodiments thereof. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the disclosure of the present invention.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0033] Example 1:

[0034] See also Figure 1 , a boom dynamic performance display method based on model reduction and digital twin. The three-dimensional model of the second boom of the drilling rig boom is selected as an example, see Figure 2 ,include:

[0035] S1: Construct a finite element mesh model based on the three-dimensional model of the boom, extract the feature information of the finite element mesh model and reconstruct the finite element mesh model. The details are as follows:

[0036] Obtain a three-dimensional model of the two-section boom, select the boom working condition fixed parameters, dynamic parameters and dynamic parameter ranges according to the actual operation of the boom, and convert the three-dimensional model into a finite element mesh model through finite element simulation software (HyperWorks2021 software produced by Altair). Select the angle θ of rotation between boom 1 and connecting shaft 2 as the dynamic parameter. When boom 1 and boom 2 are orthogonal, the angle is the initial value θ=0, and is set to the initial working condition, with the clockwise direction as the positive direction of the angle change. The working condition of the finite element mesh model is set as the rotation range of the boom 1 rotation angle θ to [-40°, 40°]. The axial thrust of boom 1 is fixed to 10KN as a static parameter, and the stress of the boom is selected as the performance display parameter. Write a Python script to extract model information to extract the node coordinate information, unit number information and the node number information contained in the finite element mesh model INP file. The finite element mesh model is reconstructed using the point, line, and surface model building mechanism of the VTK (visualization toolkit) module package in the Python programming language.

[0037] S2: Construct a proxy model of dynamic parameters and reduced low-dimensional data features, and calculate the predicted stress values ​​of all nodes of the finite element mesh model through the proxy model. The specific operations are:

[0038] The reconstructed finite element mesh model was sampled for working conditions. The thrust was fixed and the interval Δ was used as a set of sampling data. The angle θ was changed and sampled 10 times in the positive and negative directions, resulting in a total of 21 sets of simulation sample data. Static finite element simulation was performed using Abaqus to obtain a total of 21 sets of sample working conditions with different boom angles θ. 21 sets of node stress value files under different working conditions were generated. Assuming that the boom finite element model contains n nodes, a 21×n dimensional node stress value result matrix X file was obtained. The POD method (proper orthogonal decomposition method) was used to map the node stress value matrix of the sample working condition to the principal component space. The mapping process can be expressed as:

[0039] Y = X × Z;

[0040] Among them, Z is the transformation matrix with dimension n×n′, and the principal component space matrix with dimension n′ is obtained. The dimension of the reduced-order model matrix Y is 21×n′ (the principal component space dimension n′ is much smaller than the number of nodal stress values ​​n).

[0041] The interpolation method is used to establish a proxy model of the arm's arbitrary rotation angle θ and the principal component matrix Y. The expression is as follows:

[0042] Y=F(θ), F(θ)=(f(θ1),f(θ2),…f(θ n′ ))

[0043] By giving 21 simulation sample conditions, the coefficients of the interpolation proxy model F(θ) component are obtained. For any angle θ, the reduced-order model matrix Y in the principal component space at that angle is obtained. θ The dimension is 1×n′, and the node stress value vector X is obtained by inverse deduction based on the above POD method. θ :

[0044] X θ =Y θ ×Z -1

[0045] Corresponding to any rotation angle θ, the node stress value vector X of the finite element mesh model is θ The dimension is 1×n, and the stress value of each node of the finite element mesh model corresponds to the vector X θ Each component of . The POD method and interpolation method used are both numerical calculation methods. The POD inverse process of nodal stress value is matrix multiplication. The interpolation method does not involve differential equation iteration or integration process when constructing the proxy model. Because the time cost required for calculation is extremely low, it can achieve fast and efficient nodal stress value calculation and prediction.

[0046] S3: Obtain the motion base points of different components in the finite element mesh model and establish the spatial motion function module of the finite element mesh model in the VTK module. The details are as follows:

[0047] The VTK platform in Python is used to complete the reconstruction of the finite element mesh model. The reconstruction method is component by component, such as Figure 2 and Figure 3 As shown (where Figure 3The center line segment AC1 represents the boom 1 before clockwise rotation, the line segment AC2 represents the boom 1 after clockwise rotation, point A represents the rotation axis 2, point B represents the rotation axis 2 4, the line segment BC1 represents the oil cylinder before clockwise rotation, the line segment BC2 represents the oil cylinder after clockwise rotation, and the line segment AB is the connecting line between the rotation axis 2 and the rotation axis 2 4. Angle α is the angle changed after the cylinder rotates clockwise; angle β1 is the angle between the cylinder and boom 1 before clockwise rotation, β2 is the angle between the cylinder and boom 1 after clockwise rotation; θ is the angle changed after boom 1 rotates clockwise). The finite element mesh model includes 7 components, specifically including boom 1, rotation shaft 1 2, boom 2 3, rotation shaft 2 4, cylinder and rotation shaft 3 7. The boom 1 is connected to the boom 2 3 through the rotation shaft 1 2; the cylinder body 5 in the cylinder is connected to the boom 2 through the rotation shaft 2 4, and the cylinder piston rod 6 in the cylinder is connected to the boom 1 through the rotation shaft 3 7. Boom 1, cylinder piston rod 6, and rotation axis 3 7 have a motion relationship of rotation angle θ relative to boom 2 3 around rotation axis 1 2. Cylinder piston rod 6 has a motion relationship relative to boom 1 around rotation axis 3 7. Cylinder body 5 has a motion relationship relative to boom 2 3 around rotation axis 2 4. These motion relationships are not about motion around the origin of the coordinate system. Therefore, it is necessary to develop a script to establish a spatial motion function module of the finite element mesh model based on the VTK module.

[0048] Read the INP file and divide the finite element mesh model into 7 parts. Obtain the node number data and coordinate position data of the finite element mesh model corresponding to the 7 parts. Since the model unit topology structure between the parts is the same, it is only necessary to divide the different node coordinates occupied by the parts to establish the finite element mesh model of the 7 parts. The divided finite element mesh model of the boom parts can be expressed as:

[0049] C=[C1,C2,C3,C4,C5,C6,C7];

[0050] Where C represents the finite element mesh model of the boom, C1 is the vector expression of boom 1, C2 is the vector expression of rotation axis 1 2, C3 is the vector expression of boom 2 3, C4 is the vector expression of rotation axis 2 4, C5 is the vector expression of cylinder body 5, C6 is the vector expression of cylinder piston rod 6, and C7 is the vector expression of rotation axis 3 7.

[0051] Dynamic characteristics are established. The dynamic characteristics of the model are realized by the spatial changes of the node coordinates of the components. Based on Python, a rotation script R for the spatial coordinate data of the corresponding finite element mesh model components around any axis is developed. The logic of the component spatial coordinate change is as follows:

[0052] Keep the node coordinate data of the finite element mesh model components arm 2 3 and rotation axis 2 4 unchanged, arm 1 1, cylinder piston rod 6, and rotation axis 3 7 around the spatial coordinate axis 1 2, and rotate the angle θ based on the script R to obtain the new coordinate data R1 = R(C1,θ), R6 = R(C6,θ), and R7 = R(C7,θ) of arm 1 1, cylinder piston rod 6, and rotation axis 3 7. Replace the data imported into the VTK module with the new coordinate data while keeping the node number information (topology structure) unchanged to achieve the first step of model update. The updated finite element mesh model can be expressed as:

[0053] C′=[R1,C2,C3,C4,C5,R6,R7];

[0054] Then, the simplified cylinder geometry is shown in Figure 3 , the rotation angle Δα of the cylinder body 5 is:

[0055] Δα=α;

[0056] The rotation angle Δβ of the cylinder piston rod 6 is:

[0057] Δβ=β2-β1;

[0058] Using the sine and cosine formulas to solve the isosceles ΔAC1C2, we can get the relationship between Δα and Δβ with respect to the rotation angle θ: α 、U β , and get the cylinder rotation angle Δα:

[0059] Δα=U α (θ);

[0060] Cylinder rotation angle Δβ:

[0061] Δβ=U β (θ);

[0062] The new position coordinate information R6 of the cylinder piston rod 6 is rotated again around the cylinder rotation angle Δβ to obtain the final node coordinate information R′6 = R(R6, Δα). The cylinder body 5 is rotated around the cylinder rotation angle Δα to obtain the final node coordinate information R5 = R(C5, Δα). The second step of updating the finite element mesh model is completed. The finite element mesh model is fully updated based on the rotation angle θ. The reconstructed finite element mesh model can be expressed as:

[0063] C″=[R1,C2,C3,C4,R5,R′6,R7];

[0064] Where C′ represents the finite element mesh model of the boom after the rotation angle θ is changed once. The node coordinate information of the rotation axis 1 2, boom 2 3, and rotation axis 2 4 remains unchanged. The boom 1 and rotation axis 3 7 are updated once to obtain new node coordinates R1 and R7. The cylinder body 5 and cylinder piston rod 6 are updated twice to obtain new node coordinates R5 and R′6.

[0065] Based on the above steps, the update function of the node coordinate information of the finite element mesh model is realized, and the spatial motion function module of the finite element mesh model components is completed, so that the finite element mesh model has dynamic characteristics. At the same time, the spatial motion module is a numerical calculation of the data point coordinates, so it can achieve smooth model update display.

[0066] S4: Based on the VTK module, the stress values ​​are assigned to the node color rendering values ​​and updated to the finite element mesh model in real time; the processed finite element mesh model is published through the system to realize the dynamic performance display of the boom. The details are as follows:

[0067] The proxy model based on the node stress values ​​obtained in step S2 can realize the node stress value update based on the angle θ; step S3 completes the dynamic update of the spatial posture of the finite element mesh model based on the angle θ. When its posture changes, only the node coordinate information is changed, and the finite element mesh model does not show the change of the node stress value; therefore, the node stress value solved by the proxy model is mapped to the 0-255 range of the RBG color model through a normalization process, and the node color representing the node stress value of the finite element mesh model is assigned. Figure 4 On the basis of realizing the dynamic reconstruction of the model with the rotation angle θ, the dynamic update of the stress value with the rotation angle θ is realized. At this time, the spatial movement of the finite element mesh model is coordinated and synchronized with the rendering of the node stress value (the stress color rendering mapping from point to line and line to surface is completed and updated to the finite element mesh model in real time), fully realizing the dynamic mechanical performance display of the finite element mesh model.

[0068] When the finite element mesh model input angle θ changes dynamically, the changes in the model node coordinates and the calculation of the node stress values ​​only involve simple numerical operations of the data, and do not involve solving complex differential equations. Therefore, the model has an extremely fast dynamic reconstruction and stress update process, which not only achieves the requirements of smoothness in visual effects, but also meets the "virtual and real synchronization" performance requirements of virtual bodies in the application of digital twin technology.

[0069] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A boom dynamic performance display method based on model reduction and digital twinning, characterized in that: include: S1: Construct a finite element mesh model based on the three-dimensional model of the boom, extract the characteristic information of the finite element mesh model and reconstruct the finite element mesh model; S2: Construct a proxy model of dynamic parameters and reduced low-dimensional data features, and calculate the predicted stress values ​​of all nodes of the finite element mesh model through the proxy model; S3: Obtain the motion base points of different components in the finite element mesh model and establish the spatial motion function module of the finite element mesh model in the VTK module; S4: Based on the VTK module, the stress value is assigned to the node color rendering value and updated to the finite element mesh model in real time; the processed finite element mesh model is published through the system to realize the dynamic performance display of the boom; The characteristic information of the finite element mesh model includes node coordinate information, unit number information and included node number information; Reconstructing the finite element mesh model includes: using the patch function in the VTK module, based on the corresponding node number information and node coordinate information of the finite element model units in the extracted finite element mesh model, realizing the reconstruction of the finite element model units from points to surfaces to volumes, and sequentially reconstructing the extracted single finite element model units according to the extracted unit number information; The proxy model construction step includes: obtaining multiple sets of simulation sample data, selecting sample data points within the dynamic parameter value range as input dynamic parameters, calculating the stress values ​​corresponding to the sample points of the finite element mesh model using finite element analysis software, reducing the stress values ​​to obtain low-dimensional data features of the samples output by the proxy model, and constructing a proxy model of the dynamic parameters and the reduced low-dimensional data features using an interpolation method; The construction of the spatial motion function module specifically includes: selecting a set of simulation sample data as the initial working condition of the finite element mesh model and setting its initial posture state; obtaining the motion base points of different components in the finite element mesh model; establishing a motion relationship between dynamic parameters and component nodes, and writing a script program based on the motion-based unit and node spatial coordinate changes of the finite element mesh model components to obtain the spatial motion function module; The motion base points include finite element mesh model components and their coordinate positions; The step S4 is specifically as follows: based on the color rendering mapping mechanism of the VTK module, the stress value is equivalently converted into RBG color mode data, and the node color representing the stress value of the finite element mesh model node is assigned. The interpolation method of the VTK module completes the stress color rendering mapping from point to line and line to surface and updates it to the finite element mesh model in real time; the processed finite element mesh model is published through the system to realize the dynamic performance display of the boom.

2. The boom dynamic performance display method according to claim 1, characterized in that: The stress value reduction process specifically reduces the stress value by using an eigenorthogonal decomposition method.

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