Digital twinborn dynamic coal seam-oriented model and construction method thereof

Abstract

The invention discloses a digital twinborn dynamic coal seam-oriented model and a construction method thereof, and the method comprises the steps: generating a corresponding initial geological coal seam according to received initial coal seam data, and completing the coupled cooperative operation of fully-mechanized coal mining equipment and a prior floor model under the action of a physical engine and the autonomous cutting of a coal mining machine in unity 3d; based on the pose data of the coal mining machine, the position of a cutting point of a rear roller of the coal mining machine is obtained, and the coal seam floor is dynamically updated along with cutting of the coal mining machine. The coal seam floor is corrected for multiple times by considering the influence of propelling of the scraper conveyor, moving of the hydraulic support and coal falling when the coal seam floor is located in the goaf, and finally the light-weight, rapid and efficient reconstruction of the coal seam floor is achieved.

Description

Technical Field

[0001] The present invention relates to a method for dynamic reconstruction and verification of a coal seam floor, and in particular to a digital twin-oriented dynamic coal seam model and a construction method thereof. Background Art

[0002] The autonomous cutting of coal mining machines and the autonomous advancement of fully mechanized mining equipment are key technical issues in intelligent coal mining. Since the ups and downs of the coal seam floor affect the posture of the fully mechanized mining equipment, and the cutting of coal mining machines and the advancement of fully mechanized mining equipment affect the changes of the coal seam floor, therefore, accurately obtaining coal seam floor information and dynamically reconstructing it in real time as the fully mechanized mining equipment advances is the key to realizing intelligent coal mining.

[0003] Regarding the construction of the coal seam floor, the invention patent with publication number CN106296817A discloses a three-dimensional modeling method for a working face coal seam based on geological data. First, after the working face transport tunnel, working face return air tunnel and cutting eye of the coal seam to be mined are excavated and constructed, the measured geological data of the coal seam to be mined are measured; the measured geological data of the coal seam to be mined includes the three-dimensional modeling method of the coal seam, the geological data of the mining tunnel and the geological data of the cutting eye; then the coal seam model is constructed.

[0004] The invention patent with publication number CN114329687A discloses a method for constructing a virtual coal seam in an area to be mined based on small sample data. The elevation data of the coal seam at the edge of the area to be mined is obtained and saved from the tunnels and cutting eyes around the coal seam in the area to be mined. The digital elevation matrix of the coal seam model in the area to be mined is preliminarily filled with the obtained coal seam elevation data based on the double-track sweeping principle. Then, the coal seam elevation information obtained by sampling a small number of boreholes in the middle of the coal seam is used to improve the accuracy of the digital elevation matrix. Finally, a virtual coal seam that can change in real time with virtual cutting is constructed.

[0005] The invention patent with publication number CN116702445A discloses a method for reconstructing and verifying a virtual coal seam model based on the spatiotemporal data of fully mechanized mining equipment. Based on the known position information of hydraulic supports and scraper conveyors, the key points and coal seam cutting point positions required for drawing the coal seam floor are obtained, and the virtual coal seam floor model is constructed using the determined key points and coal seam cutting point positions.

[0006] In some of the above technologies, the construction of coal seam models is mainly based on coal seam geological data, and the obtained coal seam models are only static geological models that cannot reflect the dynamic change characteristics of coal seams. In other technologies, coal seam models are constructed through the posture data of fully-mechanized mining equipment, but these technologies often ignore the geological characteristics of coal seams and it is difficult to accurately describe the interaction between coal seams and fully-mechanized mining equipment. Therefore, the existing technology fails to effectively combine coal seam geological data with the posture data of fully-mechanized mining equipment, and cannot achieve accurate expression of the dynamic coal seam model of the fully-mechanized mining working face.

[0007] In addition, after analysis and comparison, the above prior art still has the following problems:

[0008] (1) Currently, the construction of three-dimensional models of coal seam floors is mostly based on geological data. However, the cost of obtaining coal seam geological data using various detection equipment is high and the accuracy is low, which cannot meet the needs of intelligent coal mining.

[0009] (2) During the coal seam construction process, although the coal seam geological data is continuously acquired and updated, the accuracy is still insufficient.

[0010] (3) Although the above coal seam construction method utilizes the position data of the comprehensive mining equipment, it does not take into account the impact of coal falling from the coal seam roof and the advancement of the comprehensive mining equipment on the coal seam floor. It ignores the mutual influence between the coal seam and the equipment, and cannot achieve dynamic reconstruction of the coal seam floor.

[0011] (4) The dynamic reconstruction of the coal seam floor is realized by using the key points of the coal seam. The calculation is large, the data processing and transmission are difficult, and the dynamic reconstruction process of the coal seam floor is not smooth enough. Summary of the invention

[0012] The purpose of the present invention is to provide a digital twin dynamic coal seam model and a construction method thereof, so as to realize lightweight, efficient and rapid construction of the coal seam floor based on the spatiotemporal operation data of comprehensive mining equipment.

[0013] To achieve the above object, according to one aspect of the present invention, a digital twin-oriented dynamic coal seam model is provided, comprising:

[0014] ——The initial coal seam module receives the initial coal seam data, forms multiple cuts and each cut sequence coal seam block with changing advancement direction according to the coal seam length, average coal seam inclination and coal seam undulation angle, and obtains the initial geological coal seam;

[0015] ——The coal mining machine cutting module imports the initial geological coal seam in Unity 3D, builds a coupled simulation scene between mining and transportation equipment and the coal seam floor, realizes the coupled collaborative simulation operation between the fully mechanized mining equipment and the floor, and the autonomous cutting of the coal mining machine. The virtual coal seam floor is dynamically reconstructed as the coal mining machine cuts, and the coal seam block data after the coal mining machine cuts is stored in the database module;

[0016] ——The scraper conveyor advancement destruction module compares the position of the scraper conveyor with the position of the coal seam block formed by the coal mining machine, clarifies the coal seam block affected by the scraper conveyor advancement, changes the posture of the affected coal seam block to show the impact of the scraper conveyor advancement, and stores the coal seam block posture after the first correction in the database module;

[0017] ——Hydraulic support frame moving and destruction module, which compares the position of the hydraulic support with the position of the coal seam block formed by the coal mining machine, clarifies the coal seam block affected by the hydraulic support frame moving, changes the posture of the affected coal seam block to show the impact of the hydraulic support frame moving, and stores the coal seam block posture after the second correction in the database module;

[0018] ——The coal falling module in the goaf area finds the coal seam blocks in the goaf area after the hydraulic support is moved, changes the posture of the coal seam blocks in the goaf area to show the impact of coal falling on the coal seam floor, and stores the coal seam block posture after the third correction in the database module;

[0019] ——Database module, used to store the coal seam block posture after cutting by the coal mining machine, the coal seam block posture after being damaged by the scraper conveyor, the coal seam block posture after being damaged by the hydraulic support frame, and the coal seam block posture after being affected by falling coal when the coal seam bottom plate is located in the goaf.

[0020] According to another aspect of the present invention, a method for constructing a digital twin dynamic coal seam model as described above is provided, comprising:

[0021] Step 1: In the initial coal seam module, the coal seam length and the coal seam undulation angle are determined according to the received initial coal seam parameters to generate the corresponding initial geological coal seam. The initial geological coal seam is generated in the form of a small coal seam block. The coal seam block has the position of the attributes X, Y, and Z and the angle of the coal seam in the three directions of X, Y, and Z, and has various physical properties.

[0022] Step 2: In the coal mining machine cutting module, the initial geological coal seam constructed in step 1 is placed at the corresponding position in Unity 3D, and a coupled simulation scene of mining and transportation equipment and coal seam floor is constructed to realize the coupled coordinated operation of fully mechanized mining equipment and coal seam floor and the autonomous cutting of the rear drum of the coal mining machine. Based on the coal mining machine's posture, rocker arm inclination angle, and coal mining machine drum radius, the position of the cutting point of the rear drum of the coal mining machine is solved; according to the position of the coal seam cutting point and the attitude angle of the coal mining machine, the virtual coal seam floor is dynamically reconstructed in Unity 3D;

[0023] Step 3: In the scraper conveyor advancement destruction module, the position size and push distance of the middle groove of the scraper conveyor are compared with the position of the coal seam block formed by the coal mining machine, and the influence range of the scraper conveyor advancement is obtained, and then the coal seam block affected by the scraper conveyor advancement is obtained; the posture of the affected coal seam block is changed to show the influence of the scraper conveyor advancement on the coal seam bottom plate, and the corrected coal seam block posture is stored in the database module;

[0024] Step 4: In the hydraulic support frame moving and destruction module, the position size and moving distance of the hydraulic support are compared with the position of the coal seam block formed by the coal mining machine, and the influence range of the scraper conveyor is obtained, and then the coal seam block affected by the scraper conveyor is obtained, and the posture of the affected coal seam block is changed to show the influence of the scraper conveyor on the coal seam bottom plate, and the corrected coal seam block posture is stored in the database module;

[0025] Step 5: In the goaf coal falling module, the newly exposed goaf is determined according to the position and size of the hydraulic support and the displacement distance of the hydraulic support, and then the coal seam blocks affected by the coal falling are determined, the posture of the affected coal seam blocks is changed to show the impact of the coal falling on the coal seam floor, and the corrected coal seam block posture is stored in the database module;

[0026] Step six, check the reconstructed coal seam floor, obtain the posture of the comprehensive mining equipment through the reconstructed and corrected coal seam floor, and compare and analyze it with the posture when the comprehensive mining equipment and the initial geological coal seam are coupled, and judge whether the dynamically generated coal seam floor meets the standard; if it does not meet the standard, correct the coal seam floor, and correct the coal seam blocks with large errors in the reconstructed coal seam floor, so as to provide a coal seam floor foundation for studying the relationship between the equipment and the subsequent movement of the equipment.

[0027] Furthermore, in the coal mining machine cutting module described in step 2, a coupling simulation scene of the mining and transportation equipment and the coal seam floor is constructed, a three-dimensional model of the coal mining machine and the scraper conveyor is established according to the actual coal mining machine and the scraper conveyor, and a physical engine is added to the coal mining machine and the scraper conveyor model, which includes the overall gravity of the model, collision bodies, and the connection joints of the middle groove of each section of the scraper conveyor, to complete the coupling simulation operation of the mining and transportation equipment with the floor model under the action of the physical engine.

[0028] Furthermore, the solution of the cutting point position of the rear drum of the coal mining machine described in step 2 is based on the posture of the coal mining machine, the inclination angle of the rocker arm and the radius of the coal mining machine drum. The position of the coal seam cutting point is solved and the position of the cutting point of the rear drum of the coal mining machine is recorded every time the coal mining machine travels one-fifth of the distance of the middle groove.

[0029] Furthermore, the autonomous cutting of the rear drum of the coal mining machine described in step 2 is regulated in Unity3D by comparing the height of the cutting point of the rear drum of the coal mining machine with the height of the coal seam block in the initial geological model that the coal mining machine is cutting at this time to adjust the lifting of the rear rocker arm of the coal mining machine.

[0030] Furthermore, the dynamic reconstruction of the virtual coal seam floor described in step 2 is that every time the coal mining machine travels one-fifth of the distance of the middle slot, a coal seam block is generated at the middle position between the cutting point position recorded this time and the cutting point position recorded last time. The size of the coal seam block is determined by the cutting depth of the coal mining machine and the width of the middle slot. The position and posture of the generated coal seam block are determined according to the recorded position of the cutting point of the coal mining machine and the posture angle of the coal mining machine to complete the dynamic reconstruction of the coal seam floor, and the posture of the coal seam block formed by the coal mining machine cutting is recorded in the database module for comparative analysis with the subsequently corrected coal seam block posture.

[0031] Furthermore, in step three, by comparing the roll angles of the (m,n)th and (m+1,n)th coal seam blocks, if the difference is too large, the roll angle of the coal seam block is adjusted, and the effect of the scraper conveyor propulsion on the coal seam floor is visualized by adjusting the posture of the coal seam block.

[0032] Furthermore, in step four, the position of the coal seam block is adjusted to characterize the sinking of the bottom plate. By comparing the posture of the hydraulic support and the posture of the coal seam block affected by the hydraulic support shifting frame, if the difference is too large, the posture of the coal seam block is changed to show the impact of the hydraulic support shifting frame on the coal seam bottom plate.

[0033] Furthermore, in step five, the coal seam block is compared with the attitude angles of the two coal seam blocks on the left and right to obtain the change in the coal seam inclination distribution. If the pitch angles of the three coal seam blocks increase from left to right and are all negative, the coal seam inclination is negative and concave; if the pitch angles of the three coal seam blocks decrease from left to right and are all positive, the coal seam inclination is positive and concave; if the pitch angles of the three coal seam blocks first decrease and then increase from left to right and the inclination changes from positive to negative, the coal seam inclination changes from positive to negative and is concave; the influence of falling coal on the coal seam floor is shown by adjusting the position or attitude angle of the coal seam blocks located on the concave surface.

[0034] Furthermore, in step six, the verification and reconstruction of the coal seam floor is to take the difference between the posture of the comprehensive mining equipment obtained by reconstructing the coal seam floor and the posture of the comprehensive mining equipment obtained by coupling the mining and transportation equipment and the initial geological coal seam, which involves the position deviation of the middle slot of the scraper conveyor: Attitude angle deviation: Position deviation of hydraulic support: Attitude angle deviation: Each section of the middle slot and hydraulic support is analyzed as a basic unit; the reliability of the floor is evaluated using position deviation and attitude angle deviation as evaluation indicators, and the deviation is compared with the upper limit of the deviation for judging whether the floor model meets the standard to determine whether it meets the standard. The middle slot and hydraulic support that do not meet the standard are extracted, located at the corresponding coal seam block, and the attitude angle of the coal seam block is corrected according to the deviation.

[0035] The digital twin dynamic coal seam model and construction method provided by the present invention dynamically reconstruct and verify the coal seam floor based on the spatiotemporal operation data of fully mechanized mining equipment. Compared with the prior art, the present invention has the following beneficial effects:

[0036] (1) The initial coal seam data can be received to determine the basic parameters of the coal seam, and a priori floor model can be generated according to the coal seam parameters, wherein the priori floor model is composed of coal seam blocks. The coal seam blocks have various physical properties, which lay the foundation for coupling with the fully mechanized mining equipment and realize lightweight construction of the initial coal seam.

[0037] (2) The autonomous cutting of the coal mining machine is realized, and the coal seam blocks are dynamically generated according to the position of the cutting point of the rear rocker arm of the coal mining machine, the attitude angle of the coal mining machine, and various parameters of the coal mining machine to dynamically update the coal seam floor, thereby realizing the dynamic reconstruction of the coal seam floor.

[0038] (3) After the coal mining machine cuts, the impact of the scraper conveyor advance, the hydraulic support shifting, and the falling coal on the coal seam floor when the coal seam floor is located in the goaf are taken into consideration. The coal seam floor after the coal mining machine cuts is corrected to obtain a coal seam floor with higher accuracy.

[0039] (4) By calibrating the coal seam floor, the position data of the comprehensive mining equipment is obtained by reconstructing the coal seam floor, and the position data of the comprehensive mining equipment obtained by coupling the mining and transportation equipment and the initial geological coal seam are compared and analyzed. According to the accuracy requirements of the coal seam, the coal seam floor is corrected multiple times, and finally a high-precision coal seam is constructed.

[0040] (5) The established database module can store the coal seam block posture after cutting by the coal mining machine, the coal seam block posture after being damaged by the scraper conveyor, the coal seam block posture after being damaged by the hydraulic support frame, and the coal seam block posture after being affected by falling coal when the coal seam floor is located in the goaf. It can make comparative analysis on the coal seam block posture at different stages, laying the foundation for intelligent coal mining.

[0041] (6) Cube blocks are used instead of coal seam blocks to construct the initial coal seam and then dynamically reconstruct the coal seam floor. The position of the coal seam blocks is continuously corrected to show the impact of scraper conveyor advancement, hydraulic support shifting, and coal falling when located in the goaf, thereby achieving lightweight, fast and efficient reconstruction of the coal seam floor. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is the overall framework diagram of the dynamic coal seam model construction of the present invention;

[0043] Figure 2 It is a flow chart of the advancement and destruction of the scraper conveyor of the present invention;

[0044] Figure 3 This is a flow chart of hydraulic support displacement and destruction of the present invention;

[0045] Figure 4 It is a flow chart of coal falling destruction in goaf area of ​​the present invention;

[0046] Figure 5 This is the flow chart of checking and reconstructing the coal seam floor of the present invention. DETAILED DESCRIPTION

[0047] The overall concept of the present invention is to dynamically update the coal seam floor according to the cutting trajectory of the coal mining machine, and continuously correct the coal seam floor with the advancement of the scraper conveyor, the movement of the hydraulic support and the impact of falling coal when the coal seam floor is located in the goaf, thereby realizing lightweight, efficient and rapid construction of the coal seam floor.

[0048] Based on the above concept, a typical implementation of the present invention provides a dynamic coal seam model for digital twins, such as Figure 1 As shown, it includes an initial coal seam module, a coal mining machine cutting module, a scraper conveyor pushing and destroying module, a hydraulic support moving and destroying module, a goaf coal falling module and a database module.

[0049] The initial coal seam module receives the initial coal seam data, forms multiple cuts and each cut sequence coal seam block with different advancing directions according to the coal seam length, the average inclination angle of the coal seam and the coal seam undulation angle, and obtains the initial geological coal seam;

[0050] Among them, the coal mining machine cutting module imports the initial geological coal seam in Unity 3D, builds the coupled simulation scene of mining and transportation equipment and coal seam floor, realizes the coupled collaborative simulation operation of comprehensive mining equipment and floor and the autonomous cutting of coal mining machine, and dynamically reconstructs the virtual coal seam floor as the coal mining machine cuts, and stores the coal seam block data after the coal mining machine cuts in the database module;

[0051] Among them, the scraper conveyor advancement destruction module compares the position of the scraper conveyor with the position of the coal seam block formed by the coal mining machine, clarifies the coal seam block affected by the scraper conveyor advancement, changes the posture of the affected coal seam block to show the impact of the scraper conveyor advancement, and stores the coal seam block posture after the first correction in the database module;

[0052] Among them, the hydraulic support frame moving and destruction module compares the position of the hydraulic support with the position of the coal seam block formed by the coal mining machine, clarifies the coal seam block affected by the hydraulic support frame moving, changes the posture of the affected coal seam block to show the impact of the hydraulic support frame moving, and stores the coal seam block posture after the second correction in the database module;

[0053] Among them, the coal falling module in the goaf finds the coal seam blocks in the goaf after the hydraulic support is moved, changes the posture of the coal seam blocks in the goaf to show the impact of the coal falling on the coal seam floor, and stores the coal seam block posture after the third correction in the database module;

[0054] Among them, the database module is used to store the coal seam block posture after cutting by the coal mining machine, the coal seam block posture after being damaged by the scraper conveyor, the coal seam block posture after being damaged by the hydraulic support frame, and the coal seam block posture after being affected by falling coal when the coal seam bottom plate is located in the goaf.

[0055] According to the above implementation method, firstly, the length of the coal seam and the undulation angle of the coal seam are determined according to the received coal seam geological data and the corresponding initial geological coal seam is generated. Then, the fully mechanized mining equipment is coupled with the prior floor model and the autonomous cutting of the coal mining machine is completed in Unity 3D under the action of the physical engine. Based on the position data of the coal mining machine, the position of the cutting point of the rear drum of the coal mining machine is obtained to realize the dynamic update of the coal seam floor as the coal mining machine cuts. Taking into account the advancement of the scraper conveyor, the coal seam floor is corrected for the first time after the coal mining machine cuts, and then the coal seam floor is corrected for the second time considering the influence of the hydraulic support frame shifting on the coal seam floor. When the coal seam floor is located in the goaf, it will be affected by the falling coal, and the coal seam floor is corrected for the third time.

[0056] Another typical embodiment of the present invention provides a method for constructing a digital twin dynamic coal seam model, including the following steps one to six.

[0057] Step 1: In the initial coal seam module, the coal seam length, number of cuts, average inclination angle of the coal seam and coal seam undulation angle are determined according to the received coal seam geological data and the corresponding initial geological coal seam is generated.

[0058] Among them, the initial geological coal seam is generated in unity3d. The coal seam is generated in the form of small coal seam blocks. The coal seam blocks have the attributes of X, Y, Z position and the angle of the coal seam in the three directions of X, Y, Z and various physical properties. These physical properties include hardness, density and collision properties.

[0059] Each coal seam block is represented by (m, n), where m represents the mth knife and n represents the nth coal seam block. Each coal seam block has a corresponding position (x, y, z) and attitude angle.

[0060] In Unity3d, by adding materials and maps to the cube blocks that constitute the initial geological model and modifying the material reflectivity, metallicity, smoothness, density, hardness and other related parameters, the initial geological model is made more realistic and more realistic. By adding Mesh Renderer and Box Collider components, the cube blocks that constitute the initial geological model have the physical properties of collision, which supports the mining and transportation equipment and lays the foundation for the coupling between the mining and transportation equipment and the coal seam floor.

[0061] Step 2: In the coal mining machine cutting module, it includes three parts: one is the construction of virtual scene; the second is the autonomous cutting of the coal mining machine; and the third is the dynamic reconstruction of the coal seam floor.

[0062] Construct a virtual scene in Unity 3D, place the initial geological coal seam constructed in step 1 in the corresponding position, establish a three-dimensional model of the coal mining machine and scraper conveyor according to the actual coal mining machine and scraper conveyor, and add a physical engine to the coal mining machine and scraper conveyor model, including the overall gravity of the model, collision body, and the connection joints of each section of the middle slot of the scraper conveyor. Before coupling with the bottom plate model, connect the guide shoe and support shoe of the coal mining machine to the middle slot of the scraper conveyor. Then determine the initial position of the equipment in the system according to the posture of the initial equipment. In order to ensure the coupling of the equipment model and the bottom plate model, it is necessary to mainly change the y coordinate of the initial equipment position. Under the action of gravity, the coupling of the equipment model and the bottom plate model is realized.

[0063] The autonomous cutting of the coal mining machine is achieved in Unity3D by comparing the height of the cutting point of the rear drum of the coal mining machine with the height of the coal seam block in the initial geological model that the coal mining machine is cutting at this time. If the height of the cutting point is greater than the height of the coal seam block, the left rocker arm of the coal mining machine moves down; if the height of the cutting point is less than the height of the coal seam block, the left rocker arm of the coal mining machine moves up, thereby realizing the autonomous cutting of the rear drum of the coal mining machine.

[0064] When the coal mining machine cuts the coal seam, the data of the new coal seam floor generated by the cutting is determined by the coal mining machine posture and the angle of the lower rocker arm of the coal mining machine. Therefore, the cutting point can be calculated based on the coal mining machine posture and the lower rocker arm inclination, combined with the drum width and radius. The coal mining machine data can reflect the shape of the newly formed coal seam floor. Therefore, in order to better dynamically update the coal seam floor, it is necessary to record the coal mining machine posture from time to time. Therefore, every time the coal mining machine travels one-fifth of the distance of the middle slot, the position of the coal mining machine cutting point and the coal mining machine posture angle are recorded.

[0065] The dynamic update of the coal seam floor is that every time the coal mining machine travels one-fifth of the distance of the middle slot, a new coal seam floor is generated according to the cutting point and posture of the coal mining machine at this time and the cutting point and posture of the coal mining machine recorded last time. The coal seam floor is also composed of coal seam blocks, so as to realize the dynamic update of the coal seam floor. The position of the newly generated coal seam block (cube block) is located at the midpoint of the cutting point of the coal mining machine at this time and the cutting point of the coal mining machine recorded last time. The size of the newly generated coal seam block is determined by the cutting depth of the coal mining machine and the width of the middle slot. The size along the horizontal advancement direction is one-fifth of the width of the middle slot, the size along the longitudinal advancement direction is the cutting depth of the coal mining machine, and the size perpendicular to the floor direction is set to one-fifteenth of the cutting depth. The pitch angle α of the coal seam block is:

[0066]

[0067] Among them, y x+1 is the height of the coal mining machine cutting point at this time, y x The height of the last recorded coal mining machine cutting point.

[0068] The roll angle of the coal seam block is the average of the roll angle of the coal mining machine at this time and the roll angle of the coal mining machine recorded last time. Here it is assumed that the straightness of the scraper conveyor is ideal, so the yaw angle of the coal seam block is 0.

[0069] Step 3: In the scraper conveyor advancement destruction module, the position size and advancement distance of the scraper conveyor middle groove are compared with the position of the coal seam block formed by the coal mining machine cutting to obtain the influence range of the scraper conveyor advancement, and then the coal seam block affected by the scraper conveyor advancement is obtained.

[0070] Considering that the scraper conveyor will exert pressure on the coal seam floor when advancing, this may cause local deformation or sinking of the coal seam floor. The sinking distance of the coal seam floor is determined according to the geological conditions and other conditions of the mined coal seam. For example, a hard floor (such as sandstone) may sink only a few millimeters to a few centimeters; a soft floor (such as mudstone) may sink tens of centimeters. The deformation of the coal seam floor is mainly reflected in the advancing direction of the scraper, which will make the coal seam floor along the advancing direction become flat. By comparing the roll angles of the (m,n) and (m+1,n) coal seam blocks, if the difference is too large, the roll angle of the coal seam block is adjusted. By adjusting the posture of the coal seam block, the effect of the scraper conveyor on the coal seam floor is shown. The adjusted coal seam block posture is stored in the database module for subsequent analysis and comparison.

[0071] Step 4: In the hydraulic support frame moving and destruction module, the position size and moving distance of the hydraulic support are compared with the position of the coal seam block formed by the coal mining machine to obtain the influence range of the hydraulic support frame moving and clarify the coal seam block affected by the hydraulic support frame moving.

[0072] During the hydraulic support frame shifting process, its base will exert pressure on the bottom plate. Although the main purpose is to support the top plate, the pressure distribution and effective area of ​​the base are larger than those of the scraper conveyor. Therefore, the impact on the bottom plate is usually a relatively uniform pressure distribution, which is not easy to cause local damage. The degree of impact on the coal seam block is determined according to the geological conditions and other conditions of the mined coal seam. In particular, when the bottom plate is a weak rock layer, the bottom plate may sink, break, and be partially damaged. The sinking of the bottom plate is characterized by adjusting the position of the coal seam block. By comparing the posture of the hydraulic support and the posture of the coal seam block affected by the hydraulic support frame shifting, if the difference is too large, the posture of the coal seam block is changed to show the impact of the hydraulic support frame shifting on the coal seam bottom plate.

[0073] Step five, in the goaf coal falling module, determine the newly exposed goaf according to the position and size of the hydraulic support and the moving distance of the hydraulic support, and then determine the coal seam blocks affected by the coal falling, and change the posture of the affected coal seam blocks to show the impact of the coal falling on the coal seam floor.

[0074] When a coal seam block is located in the goaf, the coal seam block is compared with the attitude angles of the two coal seam blocks on the left and right to obtain the change in the distribution of the coal seam inclination angle. If the size (absolute value) of the pitch angles of the three coal seam blocks increases from left to right and are all negative, the coal seam inclination angle is negative and concave; if the size (absolute value) of the pitch angles of the three coal seam blocks decreases from left to right and are all positive, the coal seam inclination angle is positive and concave. If the size (absolute value) of the pitch angles of the three coal seam blocks decreases first and then increases from left to right and the inclination angle changes from positive to negative, the coal seam inclination angle changes from positive to negative and is concave. Since coal falling will make the concave surface flat, the influence of coal falling on the coal seam floor is shown by adjusting the position or attitude angle of the coal seam block located on the concave surface, such as changing the y coordinate of the middle coal seam block to characterize the influence of coal falling.

[0075] Step six: Check and reconstruct the coal seam floor. The position and posture of the fully-mechanized mining equipment is obtained through the reconstructed and corrected coal seam floor. It is compared and analyzed with the position and posture when the fully-mechanized mining equipment and the initial geological coal seam are coupled, and it is determined whether the dynamically generated coal seam floor meets the standard. If it does not meet the standard, the coal seam floor is corrected, and the coal seam blocks with large errors in the reconstructed coal seam floor are corrected.

[0076] There are two methods to obtain the position and posture of fully mechanized mining equipment by reconstructing the coal seam floor. One is to reversely infer the position and posture of scraper conveyor and hydraulic support by reconstructing the coal seam floor. The other is to use the powerful physics engine function of unity3d to couple the mining and transportation equipment and the reconstructed coal seam floor to obtain the position and posture of scraper conveyor and hydraulic support.

[0077] Method 1: Reconstruct the coal seam bottom plate to reverse the position and posture of the scraper conveyor and the hydraulic support. The latest coal seam block position and posture recorded in the database module are used, and the corresponding points are selected on the coal seam blocks corresponding to the middle trough and hydraulic support of each section of the scraper conveyor. A plane is determined based on three points that are not on a straight line to reverse the attitude angles of the middle trough and hydraulic support of each section of the scraper conveyor, including a key point selection system and a reverse position and posture system.

[0078] The key point selection system determines the coal seam block where the middle trough of each scraper conveyor and the hydraulic support are located according to the position and size of the fully-mechanized mining equipment. The position coordinates of these coal seam blocks are known, and the coordinates of the middle point are calculated to obtain the position coordinates of the support equipment; a plane is determined based on three points, and the attitude angle of the fully-mechanized mining equipment is inferred by selecting the position coordinates of the highest coal seam blocks at three positions:

[0079] Inverse system, given three coordinates (x1, y1, z1), (x2, y2, z2), (x3, y3, z3), then Then their normal vectors are:

[0080]

[0081] Among them, a=(y1-y2)(z2-z3)-(y2-y3)(z1-z2),

[0082] b=(z1-z2)(x2-x3)-(z2-z3)(x1-x2),

[0083] c=(x1-x2)(y2-y3)-(x2-x3)(y1-y2)

[0084] In Unity, when adjusting the rotation angle of an object in the Inspector interface, the object's local coordinate system is used. This means that the rotation angle modified in the Inspector is relative to the object's own coordinate system. Specifically: the rotation angle in the Inspector is displayed in the form of Euler angles, that is, the rotation angles of the X, Y, and Z axes. These Euler angles are relative to the object's local coordinate system, not the world coordinate system. Modifying the rotation angle of the X axis will rotate around the object's local X axis. Modifying the rotation angle of the Y axis will rotate around the object's local Y axis. Modifying the rotation angle of the Z axis will rotate around the object's local Z axis. Unity uses "Tait-Bryan angles" (or YXZ order) to process Euler angles, which means that the rotation order is to rotate around the Y axis first, then around the X axis, and finally around the Z axis. The homogeneous transformation matrix for rotating around the three axes is as follows:

[0085]

[0086]

[0087]

[0088] In Unity, the ideal state of the scraper conveyor is that the floor plane coincides with the xoz plane, and its normal vector is In an ideal state, the local coordinate system of the middle trough of the scraper conveyor coincides with the world coordinate system, so the bottom surface of the middle trough first rotates α around the y-axis, then β around the x-axis, and finally γ around the z-axis, and the normal vector The coordinate system after the rotation is still (0, 1, 0). Because it is a relative coordinate system, the vector is expressed in the world coordinate system as:

[0089] but

[0090] By solving the values ​​of α, β, and γ, we can get the attitude angle of the equipment.

[0091] Method 2: Using the powerful physics engine function of Unity3D, the fully mechanized mining equipment and the reconstructed coal seam floor are coupled with each other to obtain the position and posture of the scraper conveyor and hydraulic support.

[0092] By adding physical engines to the equipment and coal seams, the coal seams corrected in step five are verified. Since the construction of the virtual scene has been completed in step two, and the corresponding physical components have been added to the reconstructed coal seam floor, the mining and transportation equipment has also completed the modeling and the addition of the physical engine. In order to ensure that the comprehensive mining equipment can be coupled with the coal seam block to be verified, the initial equipment position needs to be changed. Under the action of gravity, the coupling of the equipment model and the reconstructed coal seam floor model is realized. After the coupling of the equipment model and the floor model is completed, data extraction is performed to extract the posture information of the coupled scraper conveyor and hydraulic support.

[0093] The positions of the scraper conveyor and hydraulic support obtained by the above two methods are respectively deviated from the positions when the fully mechanized mining equipment and the initial geological coal seam are coupled to determine whether the floor model meets the standards. This involves the position deviation of the middle slot of the scraper conveyor: Attitude angle deviation: Position deviation of hydraulic support: Attitude angle deviation: The middle trough and hydraulic support of each section of the scraper conveyor are analyzed separately, and the reliability of the floor is evaluated with position deviation and attitude angle deviation as evaluation indicators. The deviation is compared with the upper limit of the deviation to judge whether the floor model meets the standard, and whether it meets the standard is determined. The upper limit of the deviation is set by oneself. If the deviation values ​​are all less than the upper limit of the deviation, it means that the coal seam floor model meets the standard; if the judgment result is not up to standard, find the coal seam block corresponding to the fully mechanized mining equipment with excessive deviation, and modify the position and posture of the coal seam block according to the deviation.

[0094] Repeat step five using the corrected coal seam floor until the virtual coal seam floor meets the requirements and then output the coal seam floor model.

[0095] The scope of protection claimed by the present invention is not limited to the above specific embodiments. For those skilled in the art, the present invention may have various deformations and changes. Any modifications, improvements and equivalent substitutions made within the concept and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A digital twin-oriented dynamic coal seam model, characterized in that: include: ——The initial coal seam module receives the initial coal seam data, forms multiple cuts and each cut sequence coal seam block with changing advancement direction according to the coal seam length, average coal seam inclination and coal seam undulation angle, and obtains the initial geological coal seam; ——The coal mining machine cutting module imports the initial geological coal seam in Unity 3D, builds a coupled simulation scene between mining and transportation equipment and the coal seam floor, realizes the coupled collaborative simulation operation between the fully mechanized mining equipment and the floor, and the autonomous cutting of the coal mining machine. The virtual coal seam floor is dynamically reconstructed as the coal mining machine cuts, and the coal seam block data after the coal mining machine cuts is stored in the database module; ——The scraper conveyor advancement destruction module compares the position of the scraper conveyor with the position of the coal seam block formed by the coal mining machine, clarifies the coal seam block affected by the scraper conveyor advancement, changes the posture of the affected coal seam block to show the impact of the scraper conveyor advancement, and stores the coal seam block posture after the first correction in the database module; ——Hydraulic support frame moving and destruction module, which compares the position of the hydraulic support with the position of the coal seam block formed by the coal mining machine, clarifies the coal seam block affected by the hydraulic support frame moving, changes the posture of the affected coal seam block to show the impact of the hydraulic support frame moving, and stores the coal seam block posture after the second correction in the database module; ——The coal falling module in the goaf area finds the coal seam blocks in the goaf area after the hydraulic support is moved, changes the posture of the coal seam blocks in the goaf area to show the impact of coal falling on the coal seam floor, and stores the coal seam block posture after the third correction in the database module; ——Database module, used to store the coal seam block posture after cutting by the coal mining machine, the coal seam block posture after being damaged by the scraper conveyor, the coal seam block posture after being damaged by the hydraulic support frame, and the coal seam block posture after being affected by falling coal when the coal seam bottom plate is located in the goaf.

2. The method for constructing a digital twin dynamic coal seam model according to claim 1, characterized in that: include: Step 1: In the initial coal seam module, the coal seam length and the coal seam undulation angle are determined according to the received initial coal seam parameters to generate the corresponding initial geological coal seam. The initial geological coal seam is generated in the form of a small coal seam block. The coal seam block has the position of the attributes X, Y, and Z and the angle of the coal seam in the three directions of X, Y, and Z, and has various physical properties. Step 2: In the coal mining machine cutting module, the initial geological coal seam constructed in step 1 is placed at the corresponding position in Unity 3D, and a coupled simulation scene of mining and transportation equipment and coal seam floor is constructed to realize the coupled coordinated operation of fully mechanized mining equipment and coal seam floor and the autonomous cutting of the rear drum of the coal mining machine. Based on the coal mining machine's posture, rocker arm inclination angle, and coal mining machine drum radius, the position of the cutting point of the rear drum of the coal mining machine is solved; according to the position of the coal seam cutting point and the attitude angle of the coal mining machine, the virtual coal seam floor is dynamically reconstructed in Unity 3D; Step 3: In the scraper conveyor advancement destruction module, the position size and push distance of the middle groove of the scraper conveyor are compared with the position of the coal seam block formed by the coal mining machine, and the influence range of the scraper conveyor advancement is obtained, and then the coal seam block affected by the scraper conveyor advancement is obtained; the posture of the affected coal seam block is changed to show the influence of the scraper conveyor advancement on the coal seam bottom plate, and the corrected coal seam block posture is stored in the database module; Step 4: In the hydraulic support frame moving and destruction module, the position size and moving distance of the hydraulic support are compared with the position of the coal seam block formed by the coal mining machine, and the influence range of the scraper conveyor is obtained, and then the coal seam block affected by the scraper conveyor is obtained, and the posture of the affected coal seam block is changed to show the influence of the scraper conveyor on the coal seam bottom plate, and the corrected coal seam block posture is stored in the database module; Step 5: In the goaf coal falling module, the newly exposed goaf is determined according to the position and size of the hydraulic support and the displacement distance of the hydraulic support, and then the coal seam blocks affected by the coal falling are determined, the posture of the affected coal seam blocks is changed to show the impact of the coal falling on the coal seam floor, and the corrected coal seam block posture is stored in the database module; Step six, check the reconstructed coal seam floor, obtain the posture of the comprehensive mining equipment through the reconstructed and corrected coal seam floor, and compare and analyze it with the posture when the comprehensive mining equipment and the initial geological coal seam are coupled, and judge whether the dynamically generated coal seam floor meets the standard; if it does not meet the standard, correct the coal seam floor, and correct the coal seam blocks with large errors in the reconstructed coal seam floor, so as to provide a coal seam floor foundation for studying the relationship between the equipment and the subsequent movement of the equipment.

3. The method according to claim 2, characterized in that: In the coal mining machine cutting module described in step 2, a coupling simulation scene of the mining and transportation equipment and the coal seam floor is constructed, and a three-dimensional model of the coal mining machine and the scraper conveyor is established according to the actual coal mining machine and the scraper conveyor. A physical engine is added to the coal mining machine and the scraper conveyor model, which includes the overall gravity of the model, collision bodies, and the connection joints of the middle groove of each section of the scraper conveyor, to complete the coupling simulation operation of the mining and transportation equipment with the floor model under the action of the physical engine.

4. The method according to claim 2 or 3, characterized in that: The solution of the cutting point position of the rear drum of the coal mining machine described in step 2 is based on the posture of the coal mining machine, the inclination angle of the rocker arm and the radius of the coal mining machine drum. The position of the coal seam cutting point is solved and the position of the cutting point of the rear drum of the coal mining machine is recorded every time the coal mining machine travels one-fifth of the distance of the middle slot.

5. The method according to claim 4, characterized in that: The autonomous cutting of the rear drum of the coal mining machine described in step 2 is regulated in Unity3D by comparing the height of the cutting point of the rear drum of the coal mining machine with the height of the coal seam block in the initial geological model that the coal mining machine is cutting at this time to adjust the lifting of the rear rocker arm of the coal mining machine.

6. The method according to claim 5, characterized in that: The dynamic reconstruction of the virtual coal seam floor described in step 2 is that every time the coal mining machine travels one-fifth of the distance of the middle slot, a coal seam block is generated at the middle position between the cutting point position recorded this time and the cutting point position recorded last time. The size of the coal seam block is determined by the cutting depth of the coal mining machine and the width of the middle slot. The position and posture of the generated coal seam block are determined according to the recorded position of the cutting point of the coal mining machine and the attitude angle of the coal mining machine to complete the dynamic reconstruction of the coal seam floor, and the posture of the coal seam block formed by the coal mining machine cutting is recorded in the database module for comparative analysis with the subsequently corrected coal seam block posture.

7. The method for constructing a digital twin dynamic coal seam model according to claim 1 or 6, characterized in that: In step three, by comparing the roll angles of the (m,n)th and (m+1,n)th coal seam blocks, if the difference is too large, the roll angle of the coal seam block is adjusted, and the effect of the scraper conveyor propulsion on the coal seam floor is revealed by adjusting the posture of the coal seam block.

8. The method for constructing a digital twin dynamic coal seam model according to claim 7, characterized in that: In step 4, the position of the coal seam block is adjusted to characterize the sinking of the bottom plate. By comparing the posture of the hydraulic support and the posture of the coal seam block affected by the hydraulic support shifting, if the difference is too large, the posture of the coal seam block is changed to show the impact of the hydraulic support shifting on the coal seam bottom plate.

9. The method for constructing a digital twin dynamic coal seam model according to claim 1 or 8, characterized in that: In step five, the coal seam block is compared with the attitude angles of the two coal seam blocks on the left and right to obtain the change in the coal seam inclination distribution. If the pitch angles of the three coal seam blocks increase from left to right and are all negative, the coal seam inclination is negative and concave; if the pitch angles of the three coal seam blocks decrease from left to right and are all positive, the coal seam inclination is positive and concave; if the pitch angles of the three coal seam blocks first decrease and then increase from left to right and the inclination changes from positive to negative, the coal seam inclination changes from positive to negative and is concave; the influence of falling coal on the coal seam floor is shown by adjusting the position or attitude angle of the coal seam blocks located on the concave surface.

10. The method for constructing a digital twin dynamic coal seam model according to claim 9, characterized in that: In step 6, the reconstructed coal seam floor is checked, and the position of the fully-mechanized mining equipment obtained by reconstructing the coal seam floor is taken as the difference between the position of the fully-mechanized mining equipment obtained by coupling the mining and transportation equipment and the initial geological coal seam, which involves the position deviation of the middle slot of the scraper conveyor: Attitude angle deviation: Position deviation of hydraulic support: Attitude angle deviation: Each section of the middle slot and hydraulic support is analyzed as a basic unit; the reliability of the floor is evaluated using position deviation and attitude angle deviation as evaluation indicators, and the deviation is compared with the upper limit of the deviation for judging whether the floor model meets the standard to determine whether it meets the standard. The middle slot and hydraulic support that do not meet the standard are extracted, located at the corresponding coal seam block, and the attitude angle of the coal seam block is corrected according to the deviation.

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