Digital twin dynamic coal seam model and construction method thereof

Abstract

The application discloses a kind of digital twin dynamic coal seam model and its construction method, first, according to the initial coal seam data received to generate corresponding initial geological coal seam, complete fully mechanized mining equipment in unity 3d under the action of physical engine and prior floor model coupling collaborative operation and the autonomous cutting of coal winning machine.Based on the pose data of coal winning machine, the position of the rear drum cutting point of coal winning machine is obtained, and the coal seam floor is dynamically updated with the cutting of coal winning machine.Considering the influence of the advance of scraper conveyor, the moving of hydraulic support and the falling of coal when the coal seam floor is in goaf, the coal seam floor is corrected multiple times, and finally the lightweight, fast and efficient reconstruction of coal seam floor is realized.

Description

TECHNICAL FIELD

[0001] The application relates to a coal seam floor dynamic reconstruction and checking method, in particular to a digital twin-oriented dynamic coal seam model and a construction method thereof. BACKGROUND

[0002] Autonomous cutting of a coal winning machine and autonomous propulsion of fully mechanized mining equipment are key technical problems of intelligent coal mining. Due to the influence of the undulating coal seam floor on the pose of the fully mechanized mining equipment, the cutting of the coal winning machine and the propulsion of the fully mechanized mining equipment affect the change of the coal seam floor. Therefore, accurate acquisition of coal seam floor information and dynamic reconstruction at any time with the propulsion of the fully mechanized mining equipment are key to realizing intelligent coal mining.

[0003] For the construction of the coal seam floor, an invention patent with the publication number CN106296817A discloses a working face coal seam three-dimensional modeling method based on geological data. First, after the working face haulage roadway, working face return airway and cut of the coal seam to be mined are all excavated and constructed, the measured geological data of the coal seam to be mined is obtained. The measured geological data of the coal seam to be mined includes a coal seam three-dimensional modeling method, geological data of a recovery roadway and geological data of a cut. Then, the coal seam model is constructed.

[0004] An invention patent with the publication number CN114329687A discloses a virtual coal seam construction method for a mining area based on small sample data. The edge coal seam elevation data of the mining area is obtained and saved from the roadway and cut around the coal seam of the mining area. The digital elevation matrix of the coal seam model of the mining area is preliminarily filled based on the obtained coal seam elevation data based on the double-track sweeping principle. Then, the precision of the digital elevation matrix is improved by using the coal seam elevation information obtained by a small amount of drilling sampling in the middle of the coal seam. Finally, a virtual coal seam capable of changing in real time with virtual cutting is constructed.

[0005] An invention patent with the publication number CN116702445A discloses a virtual coal seam model reconstruction and verification method based on space-time data of fully mechanized mining equipment. Based on the known hydraulic support and scraper conveyor pose information, the key points and coal seam cutting point positions required for drawing the coal seam floor are obtained. The construction of the virtual coal seam floor model is performed by using the determined key points and coal seam cutting point positions.

[0006] In some of the above technologies, the construction of the coal seam model is mainly based on the coal seam geological data. The obtained coal seam model is only a static geological model and cannot reflect the dynamic change characteristics of the coal seam. In some other technologies, the coal seam model is constructed by using the pose data of the fully mechanized mining equipment. However, these technologies often ignore the geological characteristics of the coal seam and are difficult to accurately describe the interaction between the coal seam and the fully mechanized mining equipment. Therefore, the existing technologies fail to effectively combine the coal seam geological data and the pose data of the fully mechanized mining equipment, and cannot accurately express the dynamic coal seam model of the fully mechanized working face.

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

[0008] (1) At present, the construction of the coal seam floor three-dimensional model is mostly based on geological data, but the use of various detection devices to obtain coal seam geological data has high cost and low precision, which cannot meet the intelligent demand of coal mining.

[0009] (2) In the process of coal seam construction, although the coal seam is continuously updated with the acquisition of coal seam geological data, the precision is still insufficient.

[0010] (3) Although the pose data of the fully mechanized mining equipment is used in the above coal seam construction method, the influence of the coal seam roof falling and the advance of the fully mechanized mining equipment on the coal seam floor is not considered, the mutual influence relationship between the coal seam and the equipment is ignored, and the dynamic reconstruction of the coal seam floor cannot be realized.

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

[0012] The purpose of the present application is to provide a digital twin dynamic coal seam model and a construction method thereof, which realizes lightweight, efficient and rapid construction of the coal seam floor based on the spatiotemporal operation data of the fully mechanized mining equipment.

[0013] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a digital twin dynamic coal seam model is provided, comprising:

[0014] An initial coal seam module receives initial coal seam data, forms each knife and each sequence coal seam block with varying advance direction according to the coal seam length, the coal seam average inclination and the coal seam fluctuation angle, and obtains an initial geological coal seam;

[0015] A coal cutter cutting module imports the initial geological coal seam in unity 3D, constructs a mining and transportation equipment and coal seam floor coupling simulation scene, realizes the coupling and collaborative simulation operation of the fully mechanized mining equipment and the floor, and the autonomous cutting of the coal cutter, and dynamically reconstructs the virtual coal seam floor with the cutting of the coal cutter, and stores the coal seam block data after cutting of the coal cutter in the database module;

[0016] A scraper conveyor advance and damage module compares the position of the scraper conveyor with the position of the coal seam block formed by the coal cutter cutting, determines the coal seam block affected by the advance of the scraper conveyor, changes the pose of the affected coal seam block to show the influence of the advance of the scraper conveyor, and stores the first corrected coal seam block pose in the database module;

[0017] The hydraulic support moving damage module compares the position of the hydraulic support with the position of the coal block formed by the coal winning machine cutting, determines the coal block affected by the hydraulic support moving, changes the pose of the affected coal block to show the influence of the hydraulic support moving, and stores the thirdly corrected coal block pose in the database module;

[0018] The goaf coal falling module finds the coal block located in the goaf after the hydraulic support moving, changes the pose of the coal block located in the goaf to show the influence of the coal falling on the coal seam floor, and stores the thirdly corrected coal block pose in the database module;

[0019] The database module is used for storing the coal block pose after the coal winning machine cutting, the coal block pose after the scraper conveyor advancing damage, the coal block pose after the hydraulic support moving damage, and the coal block pose affected by the coal falling when the coal seam floor is located in the goaf.

[0020] According to another aspect of the present application, there is provided the above-mentioned construction method for the digital twin dynamic coal seam model, comprising:

[0021] Step one, in the initial coal seam module, the initial coal seam length and the initial coal seam relief 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 small coal blocks, the coal blocks have the positions of attributes X, Y and Z and the angles of the coal seam in X, Y and Z directions, and have various physical properties;

[0022] Step two, in the coal winning machine cutting module, the initial geological coal seam constructed in step one is placed in the corresponding position in unity 3d, a mining and transportation equipment and coal seam floor coupling simulation scene is constructed, the fully mechanized mining equipment and the coal seam floor coupling collaborative operation and the autonomous cutting of the coal winning machine rear drum are realized, the position of the coal winning machine rear drum cutting point is solved based on the pose of the coal winning machine and the boom inclination angle and the coal winning machine drum radius, and the dynamic reconstruction of the virtual coal seam floor is performed in unity 3d according to the position of the coal seam cutting point and the attitude angle of the coal winning machine;

[0023] Step three, in the scraper conveyor advancing damage module, the position and size of the middle trough of the scraper conveyor and the pushing distance are compared with the position of the coal block formed by the coal winning machine cutting, the influence range of the scraper conveyor advancing is obtained, and then the coal block affected by the scraper conveyor advancing is obtained; the pose of the affected coal block is changed to show the influence of the scraper conveyor advancing on the coal seam floor, and the corrected coal block pose is stored in the database module;

[0024] Step four, in the hydraulic support moving support damage module, the position and size of the hydraulic support and the moving support distance are compared with the position of the coal block formed by the shearer cutting, the influence range of the pusher conveyor is obtained, and then the coal block affected by the pusher conveyor is obtained, the pose of the affected coal block is changed to show the influence of the pusher conveyor on the coal seam floor, and the corrected coal block pose is stored in the database module.

[0025] Step five, in the goaf coal falling module, the newly exposed goaf is determined according to the position and size of the hydraulic support and the moving distance of the hydraulic support, and then the coal block affected by the falling coal is determined, the pose of the affected coal block is changed to show the influence of the falling coal on the coal seam floor, and the corrected coal block pose is stored in the database module.

[0026] Step six, check the reconstructed coal seam floor, get the pose of the fully mechanized mining equipment through the reconstructed and corrected coal seam floor, and compare and analyze it with the pose when the fully mechanized mining equipment and the initial geological coal seam are coupled, and judge whether the dynamically generated coal seam floor meets the standard; if not, the coal seam floor is corrected, the coal block with large error in the reconstructed coal seam floor is corrected, and the coal seam floor basis is provided for the relationship between the equipment and the subsequent movement of the equipment.

[0027] Further, in the shearer cutting module of step two, a simulation scene of coupling of the mining and transportation equipment and the coal seam floor is constructed, a three-dimensional model of the shearer and the pusher conveyor is established according to the actual shearer and the pusher conveyor, a physical engine is added to the shearer and the pusher conveyor model, including the overall gravity of the model, the collision body, and the connection joint of the middle trough of each section of the pusher conveyor, and the coupling simulation running of the mining and transportation equipment with the floor model under the action of the physical engine is completed.

[0028] Further, in step two, the position of the rear drum cutting point of the shearer is solved based on the pose of the shearer and the tilt angle of the rocker arm and the radius of the shearer drum, the position of the coal cutting point is solved, and the distance of the shearer every five sections of the middle trough is recorded once the position of the rear drum cutting point of the shearer is recorded.

[0029] Further, in step two, the autonomous cutting of the rear drum of the shearer is realized by comparing the height of the rear drum cutting point of the shearer with the height of the coal block in the initial geological model being cut by the shearer at this time in unity3d to adjust the lifting of the rear rocker arm of the shearer.

[0030] Further, in step two, the dynamic reconstruction of the virtual coal seam floor, whenever the shearer travels a distance of one fifth of the middle trough, a coal seam block is generated at the middle position between the current recorded cutting point position and the last recorded cutting point position, the size of the coal seam block is determined by the cutting depth of the shearer and the width of the middle trough, the position and attitude of the coal seam block are determined according to the recorded position of the shearer cutting point and the attitude angle of the shearer, the dynamic reconstruction of the coal seam floor is completed, and the position and attitude of the coal seam block formed by the shearer cutting are recorded in the database module for comparison and analysis with the subsequent corrected coal seam block position and attitude.

[0031] Further, in step three, by comparing the roll angle 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, and the influence of the scraper conveyor propulsion on the coal seam floor is shown by adjusting the position and attitude of the coal seam block.

[0032] Further, in step four, the position of the coal seam block is adjusted to represent the subsidence of the floor, and by comparing the position and attitude of the hydraulic support with the position and attitude of the coal seam block affected by the movement of the hydraulic support, if the difference is too large, the position and attitude of the coal seam block are changed to show the influence of the movement of the hydraulic support on the coal seam floor.

[0033] Further, in step five, the attitude angles of the coal seam block and the left and right coal seam blocks are compared to obtain the distribution of the coal seam inclination angle, if the pitch angles of the three coal seam blocks increase from left to right and are all negative, the coal seam inclination angle 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 angle 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 angle changes from positive to negative, the coal seam inclination angle changes from positive to negative and is concave, and the influence of the falling coal on the coal seam floor is shown by adjusting the position or attitude angle of the concave coal seam block.

[0034] Further, in step six, the reconstructed coal seam floor is checked, and the difference between the position and attitude of the fully mechanized mining equipment obtained by reconstructing the coal seam floor and the position and attitude of the fully mechanized mining equipment obtained by coupling the initial geological coal seam with the mining and transportation equipment is calculated, which involves the position deviation of the middle trough of the scraper conveyor: Attitude angle deviation: Position deviation of the hydraulic support: Attitude angle deviation: Each middle trough and hydraulic support is analyzed as a basic unit, the position deviation and attitude angle deviation are used as evaluation indexes to evaluate the reliability of the floor, and the deviation is compared with the upper limit value of the floor model to determine whether it meets the standard. The non-compliant middle trough and hydraulic support are extracted and positioned to the corresponding coal seam block, and the attitude angle of the coal seam block is corrected according to the deviation.

[0035] The application provides a digital twin dynamic coal seam model and a construction method thereof.

[0036] (1) The initial coal seam data can be received to determine the basic parameters of the coal seam, and a prior bottom plate model is generated according to the coal seam parameters, wherein the prior bottom plate model is composed of coal seam blocks, the coal seam blocks have various physical properties, which lay a foundation for coupling with the fully-mechanized mining equipment, and the initial coal seam is constructed in a light weight.

[0037] (2) The self-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 and realize the dynamic reconstruction of the coal seam floor.

[0038] (3) After the coal mining machine cuts, the influence of the coal falling on the coal seam floor when the coal seam floor is located in the goaf is considered, the coal seam floor after the cutting of the coal mining machine is corrected to obtain a coal seam floor with higher precision.

[0039] (4) Through the method for checking the coal seam floor, the pose data of the fully-mechanized mining equipment obtained by reconstructing the coal seam floor is compared and analyzed with the pose data of the fully-mechanized mining equipment obtained by coupling the initial geological coal seam with the mining and transportation equipment, the coal seam floor is corrected for multiple times according to the precision requirement of the coal seam, and finally a high-precision coal seam is constructed.

[0040] (5) The database module can store the coal seam block pose after the cutting of the coal mining machine, the coal seam block pose after the damage of the advancing of the scraper conveyor, the coal seam block pose after the damage of the advancing of the hydraulic support, and the coal seam block pose after the influence of the coal falling when the coal seam floor is located in the goaf, and the coal seam block poses at different stages can be compared and analyzed, thereby laying a foundation for intelligent coal mining.

[0041] (6) The cube block is used instead of the coal seam block to construct the initial coal seam, and the pose of the coal seam block is dynamically reconstructed and continuously corrected to reflect the influence of the advancing of the scraper conveyor, the advancing of the hydraulic support and the coal falling when located in the goaf, and the coal seam floor is reconstructed in a light weight, fast and efficient manner. BRIEF DESCRIPTION OF DRAWINGS

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

[0043] Figure 2 is the advancing damage flowchart of the scraper conveyor of the application;

[0044] Figure 3 is the advancing damage flowchart of the hydraulic support of the application;

[0045] Figure 4 is a goaf coal falling damage flowchart of the present application;

[0046] Figure 5 is a coal seam floor checking and reconstruction flowchart of the present application. DETAILED DESCRIPTION

[0047] The overall concept of the present application 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 as the scraper conveyor advances, the hydraulic support moves, and the coal falling in the goaf affects the coal seam floor, so as to achieve lightweight and efficient and rapid construction of the coal seam floor.

[0048] Based on the above concept, a typical embodiment of the present application provides a digital twin dynamic coal seam model, as shown in Figure 1 , which includes an initial coal seam module, a coal mining machine cutting module, a scraper conveyor advancing and damaging module, a hydraulic support moving and damaging module, a goaf coal falling module, and a database module.

[0049] The initial coal seam module receives initial coal seam data, forms each knife and each sequence of coal seam blocks with multiple knives and changing advancing directions according to the coal seam length, the coal seam average inclination angle and the coal seam fluctuation angle, and obtains an initial geological coal seam.

[0050] The coal mining machine cutting module imports the initial geological coal seam in unity 3d, constructs a simulation scene of coupling between mining and transportation equipment and the coal seam floor, realizes the coupled and collaborative simulation operation of the fully mechanized mining equipment and the floor, and the autonomous cutting of the 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 cutting by the coal mining machine in the database module.

[0051] The scraper conveyor advancing and damaging module compares the position of the scraper conveyor with the position of the coal seam block formed by the coal mining machine cutting, determines the coal seam block affected by the advancing of the scraper conveyor, changes the pose of the affected coal seam block to show the influence of the advancing of the scraper conveyor, and stores the first corrected coal seam block pose in the database module.

[0052] The hydraulic support moving and damaging module compares the position of the hydraulic support with the position of the coal seam block formed by the coal mining machine cutting, determines the coal seam block affected by the moving of the hydraulic support, changes the pose of the affected coal seam block to show the influence of the moving of the hydraulic support, and stores the second corrected coal seam block pose in the database module.

[0053] The goaf coal falling module finds the coal seam block located in the goaf after the hydraulic support moves, changes the pose of the coal seam block located in the goaf to show the influence of coal falling on the coal seam floor, and stores the third corrected coal seam block pose in the database module.

[0054] The database module is used for storing the above-mentioned coal block pose after the coal winning machine cutting, the coal block pose after the scraper conveyor pushing and destroying, the coal block pose after the hydraulic support moving and destroying, and the coal block pose affected by the falling coal when the coal seam floor is located in the goaf.

[0055] According to the above embodiment, first, the coal seam length and the coal seam relief angle are determined according to the received coal seam geological data, and the corresponding initial geological coal seam is generated, the fully mechanized mining equipment is coupled and cooperatively operated with the prior floor model under the action of the physical engine in unity 3d, and the autonomous cutting of the coal winning machine is completed. Based on the pose data of the coal winning machine, the position of the rear drum cutting point of the coal winning machine is obtained, and the coal seam floor is dynamically updated with the cutting of the coal winning machine. Considering the pushing of the scraper conveyor, the coal seam floor after the cutting of the coal winning machine is corrected for the first time, and considering the influence of the hydraulic support moving on the coal seam floor, the coal seam floor is corrected for the second time. 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 application provides a construction method for a digital twin dynamic coal seam model, comprising the following steps one to step six.

[0057] Step one: in the initial coal seam module, the coal seam length, the number of knives, the average inclination of the coal seam and the relief angle of the coal seam are determined according to the received coal seam geological data, and the corresponding initial geological coal seam is generated.

[0058] 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 block has the attributes of X, Y, Z position and the angles of the coal seam in X, Y, Z three directions and various physical properties, and these physical properties include hardness, density and collision properties.

[0059] Each coal seam block is represented by (m, n), wherein 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, the cube blocks constituting the initial geological model are added with materials, maps and modified material reflectivity, metallic property, smoothness, density, hardness related parameters, so that the initial geological model is more consistent with the actual situation and more realistic, and the cube blocks constituting the initial geological model are added with Mesh Renderer and Box Collider components to have the physical properties of collision, which supports the mining and transportation equipment and lays a foundation for realizing the coupling of the mining and transportation equipment and the coal seam floor.

[0061] Step two: in the cutting module of the coal mining machine, including three parts, one is the virtual scene construction; two is the autonomous cutting of the coal mining machine; three is the dynamic reconstruction of the coal seam floor.

[0062] In unity 3d, the initial geological coal seam built in step one is placed in the corresponding position, and the 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. The physical engine is added to the model of the coal mining machine and the scraper conveyor, including the overall gravity of the model, the collision body, and the connecting joint of the middle trough of the scraper conveyor. Before coupling with the floor model, the guide shoe and the support shoe of the coal mining machine are connected with the middle trough of the scraper conveyor. Then, the initial position of the equipment in the system is determined according to the pose of the initial equipment. In order to ensure the coupling of the equipment model and the floor model, the y coordinate of the initial equipment position needs to be changed. Under the action of gravity, the coupling of the equipment model and the floor model is realized.

[0063] The autonomous cutting of the coal mining machine is realized 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 in unity 3d. If the height of the cutting point is greater than the height of the coal seam block, the left swing 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 swing 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 cutting is determined by the pose of the coal mining machine and the angle of the lower swing arm. Therefore, according to the pose of the coal mining machine and the angle of the lower swing arm, combined with the width and radius of the drum, the cutting point can be calculated. The data of the coal mining machine can reflect the shape of the newly formed coal seam floor. Therefore, in order to better update the dynamic coal seam floor, the pose of the coal mining machine needs to be recorded at all times. Therefore, whenever the coal mining machine travels a distance of one fifth of the middle trough, the position of the cutting point of the coal mining machine and the attitude angle of the coal mining machine at that time are recorded.

[0065] The dynamic update of the coal seam floor is realized by recording the cutting point and the attitude of the coal mining machine at a distance of one fifth of the middle trough every time the coal mining machine travels. According to the cutting point and the attitude of the coal mining machine at that time and the cutting point and the attitude of the coal mining machine recorded last time, a new coal seam floor is generated. The new 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 new coal seam block (cube block) is located at the midpoint between the cutting point of the coal mining machine at that 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 trough. The size along the horizontal advancing direction is one fifth of the width of the middle trough, the size along the vertical advancing 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 a of the coal seam block is:

[0066]

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

[0068] The roll angle of the coal block is the average value 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 block is 0.

[0069] Step three: In the scraper conveyor advancing damage module, the position and size of the middle trough of the scraper conveyor and the advancing distance are compared with the position of the coal block formed by the cutting of the coal mining machine, to obtain the influence range of the advancing of the scraper conveyor, and then obtain the coal block affected by the advancing of the scraper conveyor.

[0070] Considering that the scraper conveyor will exert pressure on the coal seam floor when advancing, which may cause local deformation or subsidence of the coal seam floor. According to the geological conditions and other conditions of the coal seam being mined, the subsidence distance of the coal seam floor is determined, for example: hard floor (such as sandstone), which may only have a few millimeters to a few centimeters of subsidence; soft floor (such as mudstone), which may have tens of centimeters of subsidence. The deformation of the coal seam floor mainly occurs in the advancing direction of the scraper conveyor, which makes the coal seam floor along the advancing direction tend to be flat. By comparing the roll angles of the (m, n) and (m+1, n) coal blocks, if the difference is too large, the roll angle of the coal block is adjusted, the pose of the coal block is adjusted to reflect the influence of the advancing of the scraper conveyor on the coal seam floor. And the adjusted pose of the coal block is stored in the database module for subsequent analysis and comparison.

[0071] Step four: In the hydraulic support moving damage module, the position and size of the hydraulic support and the moving distance are compared with the position of the coal block formed by the cutting of the coal mining machine, to obtain the influence range of the moving of the hydraulic support, and to determine the coal block affected by the moving of the hydraulic support.

[0072] During the moving of the hydraulic support, the base will exert pressure on the floor. Although the main purpose is to support the roof, the pressure distribution and action area of the base are larger than those of the scraper conveyor, so the influence on the floor is usually uniform pressure distribution, which is not easy to cause local damage. According to the geological conditions and other conditions of the coal seam being mined, the degree of influence of the coal block is determined, especially when the floor is a weak rock stratum, the floor may sink, break, and be locally damaged. The subsidence of the floor is represented by adjusting the position of the coal block. By comparing the pose of the hydraulic support and the pose of the coal block affected by the moving of the hydraulic support, if the difference is too large, the pose of the coal block is changed to reflect the influence of the moving of the hydraulic support on the coal seam floor.

[0073] Step five, in the goaf coal falling module, according to the position and size of the hydraulic support and the moving distance of the hydraulic support, the newly exposed goaf is determined, and then the coal seam block affected by the falling coal is determined, and the pose of the affected coal seam block is changed to show the influence of the falling coal on the coal seam floor.

[0074] When the coal seam block is located in the goaf, the attitude angle of the coal seam block and the left and right two coal seam blocks is compared to obtain the change of the coal seam dip angle distribution. If the size (absolute value) of the pitch angle of the three coal seam blocks increases from left to right and is negative, the coal seam dip angle is negative and is a concave surface. If the size (absolute value) of the pitch angle of the three coal seam blocks decreases from left to right and is positive, the coal seam dip angle is positive and is a concave surface. If the size (absolute value) of the pitch angle of the three coal seam blocks decreases from left to right and then increases, and the dip angle changes from positive to negative, the coal seam dip angle changes from positive to negative and is a concave surface. Since the falling coal will make the concave surface become gentle, the position or attitude angle of the concave coal seam block is adjusted to show the influence of the falling coal on the coal seam floor, such as changing the y coordinate of the middle coal seam block to represent the influence of the falling coal.

[0075] Step six: checking the reconstructed coal seam floor, obtaining the pose of the fully mechanized mining equipment through the reconstructed and corrected coal seam floor, comparing and analyzing the pose when the fully mechanized mining equipment and the initial geological coal seam are coupled, and judging whether the dynamically generated coal seam floor meets the standard; if not, the coal seam floor is corrected, and the coal seam block with large error in the reconstructed coal seam floor is corrected.

[0076] There are two methods to obtain the pose of the fully mechanized mining equipment through the reconstructed coal seam floor. One is to inversely deduce the pose of the scraper conveyor and the hydraulic support through the reconstructed coal seam floor, and the other is to make the mining and transportation equipment and the reconstructed coal seam floor mutually coupled by using the powerful physical engine function of unity3d to obtain the pose of the scraper conveyor and the hydraulic support.

[0077] Method one, inversely deducing the pose of the scraper conveyor and the hydraulic support through the reconstructed coal seam floor, obtaining the latest pose of the coal seam block recorded in the database module, and selecting corresponding points on the coal seam block corresponding to each section of the middle trough of the scraper conveyor and the hydraulic support, and inversely deducing the attitude angle of each section of the middle trough of the scraper conveyor and the hydraulic support according to three points not on a straight line, including a key point selection system and an inverse pose system.

[0078] The key point selection system determines the coal seam block where each section of the middle trough of the scraper conveyor and the hydraulic support is located according to the position and size of the fully mechanized mining equipment. The position coordinates of the mining and transportation equipment can be obtained by calculating the coordinates of the middle point from the known position coordinates of these coal seam blocks. The attitude angle of the fully mechanized mining equipment is inversely deduced by selecting the position coordinates of the three highest coal seam blocks according to the principle that three points determine a plane.

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

[0080]

[0081] Where 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 angles of an object in the Inspector interface, the local coordinate system of the object is used. This means that the rotation angles modified in the Inspector are relative to the object's own coordinate system. Specifically: the rotation angles in the Inspector are displayed in the form of Euler angles, that is, the rotation angles of the X, Y, Z three axes. These Euler angles are relative to the local coordinate system of the object, not the world coordinate system. Modifying the rotation angle of the X axis will rotate around the local X axis of the object. Modifying the rotation angle of the Y axis will rotate around the local Y axis of the object. Modifying the rotation angle of the Z axis will rotate around the local Z axis of the object. Unity uses "Tait-Bryan angles" (or YXZ order) to handle Euler angles, which means the rotation order is first around the Y axis, then around the X axis, and finally around the Z axis. The homogeneous transformation matrix for rotation around the three axes is as follows:

[0085]

[0086]

[0087]

[0088] In unity, the ideal state of the scraper conveyor is that its floor plane coincides with the xoz plane, and its normal vector is In the ideal state, the local coordinate system of the middle slot of the scraper conveyor coincides with the world coordinate system, so the bottom surface of the middle slot first rotates α around the y axis, then rotates β around the x axis, and finally rotates γ around the z axis, and the normal vector In the coordinate system after rotation, it is still (0, 1, 0), because it is a relative coordinate system, so the representation of this vector in the world coordinate system is:

[0089] Then

[0090] The values of α, β and γ are solved, and the attitude angle of the equipment is obtained.

[0091] In the second method, the unity3d powerful physical engine function is used to make the fully mechanized mining equipment and the reconstructed coal seam floor coupled with each other, so that the positions and postures of the scraper conveyors and the hydraulic supports are obtained.

[0092] The reconstructed coal seam is verified by adding the physical engine to the equipment and the coal seam. Since the virtual scene is constructed in the second step, and the corresponding physical components are added to the reconstructed coal seam floor, and the mining equipment is also modeled and the physical engine is added. In order to ensure that the fully mechanized mining equipment can be coupled with the coal seam blocks to be verified, the initial equipment position needs to be changed. Under the action of gravity, the coupling between the equipment model and the reconstructed coal seam floor model is realized. After the coupling between the equipment model and the floor model is completed, data extraction is performed, and the position and posture information of the coupled scraper conveyors and hydraulic supports are extracted.

[0093] The position and posture deviations of the scraper conveyors and the hydraulic supports obtained by the above two methods are respectively coupled with the fully mechanized mining equipment and the initial geological coal seam, and the position and posture deviations are compared to determine whether the floor model meets the standard. The position deviation of the middle trough of the scraper conveyor is involved: Attitude angle deviation: Position deviation of the hydraulic support: Attitude angle deviation: The position and posture deviations are used as evaluation indexes to evaluate the reliability of the floor, and the deviations are compared with the upper limit value of the floor model to determine whether it meets the standard, wherein the upper limit value is set by the user. If the deviation value is less than the upper limit deviation, it means that the coal seam floor model meets the standard; if the judgment result is not up to standard, the coal seam block corresponding to the fully mechanized mining equipment with large deviation is found, and the position and posture of the coal seam block are modified according to the deviation.

[0094] The modified coal seam floor is used to repeat step five until the virtual coal seam floor meets the requirements and the coal seam floor model is output.

[0095] The scope of protection claimed in the present application is not limited to the above specific embodiments, and the present application can have various modifications and alterations for those skilled in the art, and any modification, improvement and equivalent replacement within the concept and principles of the present application should be included in the protection scope of the present application.

Claims

1. A digital twin oriented dynamic coal seam model, characterized in that, Comprise: The initial coal seam module receives initial coal seam data, forms each knife each sequence coal seam block with multiple knives and changes in the direction of advancement according to the length of the coal seam, the average inclination of the coal seam and the relief angle of the coal seam, and obtains the initial geological coal seam; The coal winning machine cutting module imports the initial geological coal seam in unity 3d, constructs a simulation scene of coupling of mining and transportation equipment and the coal seam floor, realizes the coupled and collaborative simulation operation of the fully mechanized mining equipment and the floor and the autonomous cutting of the coal winning machine, and dynamically reconstructs the virtual coal seam floor along with the cutting of the coal winning machine, and stores the coal seam block data cut by the coal winning machine in the database module; The scraper conveyor advancing and damaging module compares the position of the scraper conveyor with the position of the coal seam block formed by the cutting of the coal winning machine, determines the coal seam block affected by the advancing of the scraper conveyor, changes the pose of the affected coal seam block to show the influence of the advancing of the scraper conveyor, and stores the first corrected coal seam block pose in the database module; The hydraulic support advancing and damaging module compares the position of the hydraulic support with the position of the coal seam block formed by the cutting of the coal winning machine, determines the coal seam block affected by the advancing of the hydraulic support, changes the pose of the affected coal seam block to show the influence of the advancing of the hydraulic support, and stores the second corrected coal seam block pose in the database module; The goaf coal falling module finds the coal seam block located in the goaf after the advancing of the hydraulic support, changes the pose of the coal seam block located in the goaf to show the influence of the coal falling on the coal seam floor, and stores the third corrected coal seam block pose in the database module; The database module is used for storing the coal seam block pose after the cutting of the coal winning machine, the coal seam block pose after the advancing and damaging of the scraper conveyor, the coal seam block pose after the advancing and damaging of the hydraulic support, and the coal seam block pose affected by the coal falling when the coal seam floor is located in the goaf.

2. The method for constructing a digital twin-oriented dynamic coal seam model according to claim 1, characterized in that, Comprise: Step one, in the initial coal seam module, determine the length of the coal seam and the relief angle of the coal seam 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 small coal seam blocks, the coal seam block has the position of attributes X, Y, Z and the angle of the coal seam in X, Y, Z three directions, and has various physical properties; Step two, in the coal winning machine cutting module, place the initial geological coal seam constructed in step one in the corresponding position in unity 3d, construct a simulation scene of coupling of mining and transportation equipment and the coal seam floor, realize the coupled and collaborative operation of the fully mechanized mining equipment and the coal seam floor and the autonomous cutting of the rear drum of the coal winning machine, solve the position of the cutting point of the rear drum of the coal winning machine based on the pose of the coal winning machine and the inclination of the rocker arm and the radius of the drum of the coal winning machine; according to the position of the coal seam cutting point and the attitude angle of the coal winning machine, dynamically reconstruct the virtual coal seam floor in unity3d; Step three, in the scraper conveyor advancing and damaging module, compare the position and size of the middle trough of the scraper conveyor with the position of the coal seam block formed by the cutting of the coal winning machine, obtain the influence range of the advancing of the scraper conveyor, and then obtain the coal seam block affected by the advancing of the scraper conveyor; change the pose of the affected coal seam block to show the influence of the advancing of the scraper conveyor on the coal seam floor, and store the corrected coal seam block pose in the database module; Step four, in the hydraulic support moving support destruction module, the position and size of the hydraulic support and the moving support distance are compared with the position of the coal block formed by the cutting of the coal winning machine, the influence range of the pusher conveyor is obtained, and then the coal block affected by the pusher conveyor is obtained, the pose of the affected coal block is changed to show the influence of the pusher conveyor on the coal seam floor, and the corrected coal block pose is stored in the database module; Step five, in the goaf coal falling module, the newly exposed goaf is determined according to the position and size of the hydraulic support and the moving support distance of the hydraulic support, and then the coal block affected by the falling coal is determined, the pose of the affected coal block is changed to show the influence of the falling coal on the coal seam floor, and the corrected coal block pose is stored in the database module; Step six, check the reconstructed coal seam floor, get the pose of the fully mechanized mining equipment through the reconstructed and corrected coal seam floor, and compare and analyze the pose when the fully mechanized mining equipment and the initial geological coal seam are coupled, and judge whether the dynamically generated coal seam floor meets the standard; If not, correct the coal seam floor, correct the coal block with large error in the reconstructed coal seam floor, and provide the coal seam floor basis for studying the relationship between the equipment and the subsequent movement of the equipment.

3. The construction method of the digital twin dynamic coal seam model according to claim 2, characterized in that: In the coal winning machine cutting module of step two, a simulation scene of the mining and transportation equipment coupled with the coal seam floor is constructed, a three-dimensional model of the coal winning machine and the pusher conveyor is established according to the actual coal winning machine and the pusher conveyor, a physical engine is added to the coal winning machine and the pusher conveyor model, including the overall gravity of the model, the collision body, and the connection joint of the middle trough of each section of the pusher conveyor, and the mining and transportation equipment is coupled and simulated with the floor model under the action of the physical engine.

4. The construction method of the digital twin dynamic coal seam model according to claim 2 or 3, characterized in that: In step two, the position of the rear drum cutting point of the coal winning machine is solved based on the pose of the coal winning machine, the tilt angle of the rocker arm, and the radius of the drum of the coal winning machine, the position of the coal cutting point is solved, and the position of the rear drum cutting point of the coal winning machine is recorded once every five-sixth of the distance of the middle trough.

5. The construction method of the digital twin dynamic coal seam model according to claim 4, characterized in that: In step two, the autonomous cutting of the rear drum of the coal winning machine is realized by comparing the height of the rear drum cutting point of the coal winning machine with the height of the coal block in the initial geological model being cut by the coal winning machine at this time to adjust the lifting of the rear rocker arm of the coal winning machine.

6. The construction method of the digital twin dynamic coal seam model according to claim 5, characterized in that: The dynamic reconstruction of the virtual coal seam floor in step two generates a coal seam block at the middle position between the current recorded cutting point position and the last recorded cutting point position every time the shearer travels a distance of one-fifth of the middle trough, and the size of the coal seam block is determined by the cutting depth of the shearer and the width of the middle trough. The position and attitude of the coal seam block are determined according to the recorded position of the shearer cutting point and the attitude angle of the shearer. The dynamic reconstruction of the coal seam floor is completed, and the position and attitude of the coal seam block formed by the shearer cutting are recorded in the database module for comparison and analysis with the subsequent corrected coal seam block position and attitude.

7. The method of claim 2 or 6, wherein: In step three, the roll angle of the coal seam block is adjusted 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 to reflect the influence of the scraper conveyor pushing on the coal seam floor.

8. The method of claim 7, wherein: In step four, the position of the coal seam block is adjusted to represent the subsidence of the floor. By comparing the position of the hydraulic support and the position of the coal seam block affected by the movement of the hydraulic support, if the difference is too large, the position of the coal seam block is changed to reflect the influence of the movement of the hydraulic support on the coal seam floor.

9. The method of claim 2 or 8, wherein: In step five, the attitude angles of the coal seam block and the left and right coal seam blocks are compared to obtain the distribution of the coal seam inclination angle. If the pitch angles of the three coal seam blocks increase from left to right and are all negative, the coal seam inclination angle 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 angle 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 angle changes from positive to negative, the coal seam inclination angle changes from positive to negative and is concave. The position or attitude angle of the coal seam block in the concave coal seam is adjusted to reflect the influence of the falling coal on the coal seam floor.

10. The method of claim 9, wherein: In step six, the reformed coal seam floor is checked, and the pose of the fully mechanized mining equipment obtained by reformation of the coal seam floor is subtracted from the pose of the fully mechanized mining equipment obtained by coupling of the mining and transporting equipment and the initial geological coal seam, wherein the position deviation of the middle trough of the scraper conveyor is involved: , the attitude angle deviation: , the position deviation of the hydraulic support: , the attitude angle deviation: , the position deviation of the middle trough and the hydraulic support in each section are analyzed respectively; the reliability of the floor is evaluated by taking the position deviation and the attitude angle deviation as evaluation indexes, and the deviation is compared with the upper limit value of the floor model to determine whether the floor meets the standard; the middle trough and the hydraulic support that do not meet the standard are extracted and positioned to the corresponding coal seam block, and the attitude angle of the coal seam block is corrected according to the deviation.

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