Method for accurately monitoring and analyzing gas in coal mine goaf

Abstract

The invention relates to the technical field of intelligent control, in particular to a coal mine goaf gas accurate monitoring analysis method, which comprises the following steps: acquiring a harmful gas concentration data sequence of monitoring points, determining a target monitoring point according to the fluctuation degree of monitoring data of each monitoring point, and drawing a coal mine goaf digraph, and determining a final optimal path passing through each target monitoring point, determining a reference monitoring point of each target monitoring point according to the final optimal path, and determining updated monitoring data of each target monitoring point according to the monitoring data of the reference monitoring point of each target monitoring point and the distance from the reference monitoring point to the air inlet. According to the invention, the monitoring point data is updated, the monitoring data error caused by sensor distortion is reduced, and the monitoring precision of the sensor is improved.

Description

Technical Field

[0001] The present invention relates to the field of intelligent control technology, and in particular to a method for accurately monitoring and analyzing gas in a coal mine goaf. Background Art

[0002] In the goaf of coal mines, the presence of highly dangerous gases is a safety hazard that cannot be ignored. For example, methane and carbon monoxide can easily cause fires and explosions when the concentration is too high, posing a serious threat to the lives of miners. Therefore, in order to effectively prevent and control such hazards, multiple monitoring points must be set up in key areas of coal mines to conduct continuous and real-time monitoring of the concentration of dangerous gases in the surrounding environment, promptly detect abnormal changes in gas concentrations, and quickly notify miners and managers through advanced early warning systems. Once potential dangers are detected, relevant personnel can immediately take necessary emergency measures, such as evacuating personnel, starting ventilation systems or using inhibitors, thereby effectively avoiding the occurrence of dangerous accidents and ensuring the safe operation of mines.

[0003] At present, the monitoring of hazardous gases in coal mines mainly relies on various types of sensors. However, the performance of sensors may be affected by many factors, such as ambient temperature, humidity, dust, etc., which may cause distortion of sensor readings. Distorted monitoring data will not only reduce the accuracy of monitoring, but also delay the response to changes in hazardous gas concentrations, increase the risk of accidents, and affect the safety management and control of coal mines. Summary of the invention

[0004] The invention provides a method for accurately monitoring and analyzing gas in a coal mine goaf to solve the existing problems.

[0005] The method for accurate gas monitoring and analysis in a coal mine goaf of the present invention adopts the following technical scheme:

[0006] Acquire a harmful gas concentration data sequence of a monitoring point, acquire the fluctuation degree of the harmful gas concentration data of each monitoring point, and determine a target monitoring point according to the fluctuation degree of the harmful gas concentration data of each monitoring point; the harmful gas concentration data sequence includes the harmful gas concentration data at the current moment;

[0007] Draw a directed graph of the coal mine goaf, and determine the weights between the nodes according to the distances and out-degrees between the nodes in the directed graph; the nodes include the air inlet, air outlet, intersection and monitoring point of the coal mine goaf, and the direction from the air inlet to the air outlet is taken as the positive direction in the directed graph; determine the optimal path from the air inlet to the target monitoring point and the optimal path from the target monitoring point to the air outlet according to the weights between the nodes;

[0008] Determine the final best path passing through the target monitoring point according to the angle between the best path from the air inlet to the target monitoring point and the best path from the target monitoring point to the air outlet, and determine the reference monitoring point of the target monitoring point according to the final best path passing through the target monitoring point;

[0009] According to the harmful gas concentration data of the reference monitoring point of the target monitoring point and the distance to the air inlet, the updated harmful gas concentration data of the target monitoring point is determined.

[0010] Furthermore, the specific method of obtaining the fluctuation degree of the harmful gas concentration data at each monitoring point includes:

[0011] All data in the harmful gas concentration data sequence of the i-th detection point are smoothed using mean filtering to obtain a smoothed sequence;

[0012] The norm normalization function is used to normalize the variance of all data in each smooth sequence, and the normalization result is used as the fluctuation degree of the harmful gas concentration data at the i-th monitoring point.

[0013] Furthermore, the target monitoring point is determined according to the fluctuation degree of the harmful gas concentration data at each monitoring point, and the specific method includes:

[0014] If the fluctuation degree of the harmful gas concentration data at the ith monitoring point is greater than a preset first threshold, the ith monitoring point is used as a target monitoring point.

[0015] Furthermore, the specific method of determining the weights between nodes includes:

[0016] The distance between nodes and the out-degree of each node in the positive direction of the directed graph of the coal mine goaf is obtained, and the product of the distance between any node and the next node in the positive direction and the out-degree of any node in the positive direction is used as the weight between the any node and the next node.

[0017] Furthermore, the specific method of determining the optimal path from the air inlet to the target monitoring point and the optimal path from the target monitoring point to the air outlet includes:

[0018] Take any air inlet as the starting node, count all different paths from the jth target monitoring point to the starting node in the directed graph, obtain the updated distance of each path according to the weights between the nodes on each path, and take the path corresponding to the minimum updated distance of all paths as the optimal path from any air inlet to the jth target monitoring point;

[0019] According to the method for obtaining the best path from each air inlet to each target monitoring point, the best path from each target monitoring point to each air outlet is obtained.

[0020] Furthermore, the specific method for obtaining the updated distances of all paths is:

[0021] The sum of the weights between all adjacent nodes on each path is recorded as the updated distance of each path.

[0022] Furthermore, the specific method of determining the final optimal path passing through the target monitoring point includes:

[0023] The best path from the air inlet to the jth target monitoring point is recorded as the P path, and the best path from the jth target monitoring point to the air outlet is recorded as the Q path. In the directed graph, straight line fitting is performed on all nodes on the pth P path and all nodes on the qth Q path, respectively, to obtain the fitting straight line corresponding to the pth P path and the fitting straight line corresponding to the qth Q path, and the maximum angle θ formed by the fitting straight line corresponding to the pth P path and the fitting straight line corresponding to the qth Q path is calculated. p,q The path formed by the P path and the Q path corresponding to the maximum value of the maximum angle formed by the fitting straight lines corresponding to all P paths and the fitting straight lines corresponding to all Q paths is recorded as the final optimal path passing through the jth target monitoring point.

[0024] Furthermore, the specific method of determining the reference monitoring point of the target monitoring point according to the final optimal path passing through the target monitoring point includes:

[0025] All monitoring points on the final optimal path passing through the j-th target monitoring point are obtained, and all monitoring points except the j-th target monitoring point are recorded as reference detection points.

[0026] Furthermore, the determination of updated harmful gas concentration data of the target monitoring point includes the following specific methods:

[0027] Get the distance x from the jth target monitoring point to the air outlet w , find the horizontal coordinate x on the distance-concentration change curve of the reference monitoring point w The corresponding ordinate y w , then we get y w , recorded as the updated monitoring data of the jth target monitoring point at the current moment.

[0028] Furthermore, the specific method for obtaining the distance-concentration variation curve of the reference monitoring point is:

[0029] In the final optimal path passing through the jth target monitoring point, obtain the distance x from the vth reference monitoring point to the air inlet. v And the harmful gas concentration data y of the vth reference monitoring point at the current moment v , get the coordinates of the vth reference monitoring point (x v ,yv ), the coordinates of all reference monitoring points are mapped to the rectangular coordinate system, and the least squares method is used to perform curve fitting on all data points on the rectangular coordinate system to obtain the distance-concentration change curve of the reference monitoring point.

[0030] An embodiment of the present invention provides a method for accurately monitoring and analyzing gas in a coal mine goaf, the method comprising the following steps:

[0031] The beneficial effects of the technical solution of the present invention are: obtaining a data sequence of harmful gas concentrations at monitoring points, obtaining the degree of fluctuation of harmful gas concentration data at each monitoring point, and determining a target monitoring point according to the degree of fluctuation of harmful gas concentration data at each monitoring point, which is helpful to determine the analysis target, narrow the scope of analysis, draw a directed graph of a coal mine goaf, and determine the weights between nodes according to the distances and out-degrees between nodes in the directed graph, wherein the nodes include air inlets, air outlets, intersections and monitoring points in the coal mine goaf, and the direction from the air inlet to the air outlet is used as the positive direction in the directed graph; according to the weights between the nodes, determine the optimal path from the air inlet to the target monitoring point and the optimal path from the target monitoring point to the air outlet , which helps to determine the best path through the target monitoring point, and determines the final best path through the target monitoring point according to the angle between the best path from the air inlet to the target monitoring point and the best path from the target monitoring point to the air outlet. The reference monitoring point of the target monitoring point is determined according to the final best path through the target monitoring point, which helps to analyze and determine the updated harmful gas concentration data of the target monitoring point, and determines the updated harmful gas concentration data of the target monitoring point according to the harmful gas concentration data of the reference monitoring point of the target monitoring point and the distance to the air inlet, so as to accurately monitor the harmful gases in the goaf of the coal mine, reduce the sensor distortion caused by other factors, and improve the monitoring accuracy of the sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 A flow chart of the steps of a method for accurately monitoring and analyzing gas in a coal mine goaf according to the present invention;

[0034] Figure 2 A schematic diagram of a directed graph of a coal mine goaf provided by the present invention;

[0035] Figure 3 A schematic diagram of the distances between nodes in a directed graph of a coal mine goaf provided by the present invention;

[0036] Figure 4 A schematic diagram of the out-degree of the directed graph nodes of the coal mine goaf provided by the present invention;

[0037] Figure 5 A schematic diagram of weights between nodes of a directed graph of a coal mine goaf provided by the present invention. DETAILED DESCRIPTION

[0038] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of the specific implementation method, structure, characteristics and effects of a method for accurate gas monitoring and analysis in a coal mine goaf area proposed by the present invention in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0039] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0040] The specific scheme of the method for accurate gas monitoring and analysis in coal mine goaf provided by the present invention is described in detail below with reference to the accompanying drawings.

[0041] See also Figure 1 , which shows a flow chart of the steps of a method for accurate gas monitoring and analysis in a coal mine goaf provided by an embodiment of the present invention, the method comprising the following steps:

[0042] Step S001: Obtain a harmful gas concentration data sequence of a monitoring point, obtain the degree of fluctuation of the harmful gas concentration data of each monitoring point, and determine a target monitoring point according to the degree of fluctuation of the harmful gas concentration data of each monitoring point; the harmful gas concentration data sequence includes the harmful gas concentration data at the current moment.

[0043] It should be noted that the distortion of the sensor is manifested as random fluctuations in the output value due to interference from external factors, resulting in large fluctuations in the data monitored at each monitoring point. Therefore, the monitoring points with sensor distortion can be determined based on the degree of fluctuation of the harmful gas concentration data at each monitoring point over a period of time.

[0044] Specifically, in order to implement the method for accurate gas monitoring and analysis in coal mine goafs proposed in this embodiment, it is first necessary to determine the target monitoring point. The specific process is as follows:

[0045] First, the harmful gas concentration data monitored every hour at the current moment and within 24 hours before the current moment of any monitoring point are obtained, and the set of the data is used as the monitoring data sequence of the monitoring point. A window with a length of A is set, and any data in the data sequence of any monitoring point is taken as the center. The mean of all data in the window where the arbitrary data is located is taken as the value of the data after smoothing. Thus, all data in the harmful gas concentration data sequence of the i-th detection point are smoothed using mean filtering, and the monitoring data sequence after smoothing is recorded as a smoothed sequence. This is a well-known technology.

[0046] Then, the norm normalization function is used to normalize the variance of all data in each smooth sequence, and the normalized result is used as the fluctuation degree of the harmful gas concentration data at the i-th monitoring point, recorded as Tp i , calculate the fluctuation degree of harmful gas concentration data at all monitoring points, preset the first threshold, if Tp i If the value is greater than a preset first threshold, the i-th monitoring point is regarded as a monitoring point with sensor distortion, that is, a target monitoring point.

[0047] It should be noted that the fluctuation degree Tp of the harmful gas concentration data at the i-th monitoring point i The larger the value, the greater the fluctuation of the harmful gas concentration data at the i-th monitoring point, the greater the possibility of data distortion of the sensor at the monitoring point, and the less real the monitored gas concentration data. i The smaller the value, the smaller the fluctuation of the harmful gas concentration data at the monitoring point, and the smaller the possibility of distortion of the sensor at the monitoring point.

[0048] It should be noted that the preset value of A is 7, and the preset value of the first threshold is 0.8, which can be adjusted according to actual conditions. This embodiment does not make specific limitations. In this embodiment, harmful gases include methane and carbon monoxide.

[0049] So far, several target monitoring points have been obtained through the above method.

[0050] Step S002: Draw a directed graph of the coal mine goaf, and determine the weights between the nodes according to the distances and out-degrees between the nodes in the directed graph; the nodes include the air inlet, air outlet, intersection and monitoring point of the coal mine goaf, and the direction from the air inlet to the air outlet is taken as the positive direction in the directed graph; according to the weights between the nodes, determine the optimal path from the air inlet to the target monitoring point and the optimal path from the target monitoring point to the air outlet.

[0051] It should be noted that the ventilation system of a coal mine is used to remove harmful gases such as methane accumulated in the goaf. It transports fresh air to the goaf from the air inlet and discharges exhaust gas and harmful gases out of the mine from the air outlet. Therefore, the data monitored by the monitoring points in the same direction have a certain correlation. Under ideal circumstances, the data monitored by the monitoring points on the straight line distance from the air inlet to the air outlet have the strongest correlation. However, the actual working face path structure of the goaf of a coal mine is complex and there are multiple forks, which affects the diffusion of harmful gases in the goaf. Therefore, the optimal path from the target monitoring point to the air outlet is determined based on the distance between the monitoring points in the goaf of the coal mine and the number of detection points.

[0052] Step (2.1), draw a directed graph of the coal mine goaf, and determine the weights between the nodes according to the distance and out-degree between the nodes in the directed graph. The nodes include the air inlet, air outlet, intersection and monitoring point of the coal mine goaf. In the directed graph, the direction from the air inlet to the air outlet is taken as the positive direction.

[0053] It should be noted that the path length between the air inlet and the monitoring point will affect the correlation of the data monitored by the monitoring point. The longer the path between the air inlet and the monitoring point, the worse the correlation between the data monitored by the monitoring points on the path. At the same time, the number of intersections on the path will also affect the correlation between the data monitored by the monitoring points at the intersections. The more intersections on the path, the wider the diffusion range of the gas passing through the path, and the worse the correlation between the data monitored by the monitoring points on the path. Therefore, the weights between nodes are determined based on the distance between two adjacent nodes in the directed graph and the number of intersections in the positive direction of the nodes.

[0054] First, the air inlet, air outlet, intersection and monitoring point of the coal mine goaf are taken as nodes, and the direction from the air inlet to the air outlet is taken as the positive direction. All nodes can form a directed graph, such as Figure 2 The figure shows an example of a directed graph, in which there are multiple air inlets and outlets.

[0055] Then, the distance between nodes in the positive direction of the directed graph of the coal mine goaf and the out-degree of each node are obtained. The out-degree of each node is the number of edges in the positive direction with each node as the starting point. The out-degree of each node in the positive direction is used to represent the number of forks in the positive direction of each intersection. The product of the distance between any node in the positive direction and the next node and the out-degree of any node in the positive direction is used as the weight between the arbitrary node and the next node.

[0056] It should be noted that the smaller the distance between any node and the next node in the positive direction of the directed graph, and the smaller the out-degree of the arbitrary node, the smaller the weight between the arbitrary node and the next node, and the stronger the correlation between the monitoring data of the monitoring points passing through the node, and vice versa. Figure 3 , Figure 4 as well as Figure 5 The figure shows all the paths from the air inlet A to the target monitoring point F. The values ​​on the edges between nodes A, B, C, D, E, and F represent the distance, out-degree, and weight, respectively.

[0057] Step (2.2), based on the weights between the nodes, determine the optimal path from the air inlet to the target monitoring point and the optimal path from the target monitoring point to the air outlet.

[0058] It should be noted that this embodiment adopts the idea of ​​greedy strategy and breadth-first traversal, and selects the node with the smallest weight in the current path for expansion each time, ensuring that the shortest path length of each node is the optimal solution, that is, the best choice in the current state is taken in each step of selection, so as to find the best path from the air inlet to the target monitoring point.

[0059] Specifically, first, any air inlet is taken as the starting node, and all different paths between the j-th target monitoring point and the starting node in the directed graph are counted. The sum of the weights between all adjacent nodes on each path is recorded as the updated distance of each path, and the path corresponding to the minimum updated distance of all paths is taken as the optimal path from the starting node to the j-th target monitoring point.

[0060] Thus, the optimal path from each air inlet to each target monitoring point is obtained.

[0061] Then, according to the method for obtaining the best path from each air inlet to each target monitoring point, the best path from each target monitoring point to each air outlet is obtained.

[0062] So far, the optimal path from the air inlet to the target monitoring point and the optimal path from the target monitoring point to the air outlet are obtained through the above method.

[0063] Step S003, determine the final optimal path passing through the target monitoring point according to the angle between the optimal path from the air inlet to the target monitoring point and the optimal path from the target monitoring point to the air outlet, and determine the reference monitoring point of the target monitoring point according to the final optimal path passing through the target monitoring point.

[0064] It should be noted that in the goaf of a coal mine, there will be multiple air inlets and outlets, so that there will be more than one optimal path passing through the target monitoring point obtained according to the above method. Under ideal conditions, the closer the path passing through the target monitoring point is to a straight line, that is, the more consistent the direction of the optimal path from the air inlet to the target monitoring point and the optimal path from the target monitoring point to the air outlet, the higher the correlation of the data monitored by the monitoring points on the path, so it is necessary to compare and analyze multiple optimal paths to determine the final optimal path.

[0065] Specifically, first, the best path from the air inlet to the jth target monitoring point is recorded as the P path, and the best path from the jth target monitoring point to the air outlet is recorded as the Q path. In the directed graph, straight line fitting is performed on all nodes on the pth P path and all nodes on the qth Q path, respectively, to obtain the fitting straight line corresponding to the pth P path and the fitting straight line corresponding to the qth Q path, and the maximum angle θ formed by the fitting straight line corresponding to the pth P path and the fitting straight line corresponding to the qth Q path is calculated. p,q The path formed by the P path and the Q path corresponding to the maximum value of the maximum angle formed by the fitting straight lines corresponding to all P paths and the fitting straight lines corresponding to all Q paths is recorded as the final optimal path passing through the jth target monitoring point.

[0066] It should be noted that, if there are multiple maximum values ​​of the maximum angle, one is randomly selected as an example for analysis.

[0067] It should be noted that the angle θ between the pth P path and the qth Q path is p,q The larger it is, the closer the path formed by the corresponding P path and Q path is to a straight line, which means that the correlation of the data monitored by the monitoring points on the path is higher, otherwise, the smaller it is.

[0068] Then, all monitoring points on the final optimal path passing through the j-th target monitoring point are obtained, and all monitoring points except the j-th target monitoring point are recorded as reference detection points.

[0069] So far, the reference monitoring point of the target monitoring point is obtained through the above method.

[0070] Step S004, determining updated harmful gas concentration data of the target monitoring point according to the harmful gas concentration data of the reference monitoring point of the target monitoring point and the distance to the air inlet.

[0071] It should be noted that the concentration of harmful gases monitored by the reference monitoring point of the target monitoring point has a certain changing trend. Specifically, the closer the monitoring point is to the air inlet, the smaller the concentration of harmful gases monitored, and the farther away from the air inlet, that is, the closer to the air outlet, the greater the concentration of harmful gases. That is, from the air inlet to the air outlet, the concentration of harmful gases monitored by the monitoring point gradually increases. Therefore, the monitoring data of the target monitoring point can be corrected according to the changing trend of the monitoring data of the reference monitoring point.

[0072] Specifically, first, in the final optimal path passing through the jth target monitoring point, obtain the distance x from the vth reference monitoring point to the air inlet v And the harmful gas concentration data y of the vth reference monitoring point at the current moment v , get the coordinates of the vth reference monitoring point (x v ,y v ), the coordinates of all reference monitoring points are mapped to a rectangular coordinate system, and the least squares method is used to perform curve fitting on all data points on the rectangular coordinate system to obtain a distance-concentration change curve of the reference monitoring point, wherein the horizontal axis of the change curve is the distance from the reference monitoring point to the air inlet, and the vertical axis is the harmful gas concentration data of the reference monitoring point at the current moment.

[0073] Then, obtain the distance x from the jth target monitoring point to the air outlet w , find the horizontal coordinate x on the distance-concentration change curve of the reference monitoring point w The corresponding ordinate y w , then we get y w That is, the updated monitoring data of the jth target monitoring point at the current moment.

[0074] At this point, this embodiment is completed.

[0075] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for accurate gas monitoring and analysis in coal mine goaf, characterized in that: The method comprises the following steps: Acquire a harmful gas concentration data sequence of a monitoring point, acquire the fluctuation degree of the harmful gas concentration data of each monitoring point, and determine a target monitoring point according to the fluctuation degree of the harmful gas concentration data of each monitoring point; the harmful gas concentration data sequence includes the harmful gas concentration data at the current moment; Draw a directed graph of the coal mine goaf, and determine the weights between the nodes according to the distances and out-degrees between the nodes in the directed graph; the nodes include the air inlet, air outlet, intersection and monitoring point of the coal mine goaf, and the direction from the air inlet to the air outlet is taken as the positive direction in the directed graph; determine the optimal path from the air inlet to the target monitoring point and the optimal path from the target monitoring point to the air outlet according to the weights between the nodes; Determine the final best path passing through the target monitoring point according to the angle between the best path from the air inlet to the target monitoring point and the best path from the target monitoring point to the air outlet, and determine the reference monitoring point of the target monitoring point according to the final best path passing through the target monitoring point; According to the harmful gas concentration data of the reference monitoring point of the target monitoring point and the distance to the air inlet, the updated harmful gas concentration data of the target monitoring point is determined.

2. According to claim 1, a method for accurate gas monitoring and analysis in coal mine goaf, characterized in that: The specific method for obtaining the fluctuation degree of the harmful gas concentration data at each monitoring point includes: All data in the harmful gas concentration data sequence of the i-th detection point are smoothed using mean filtering to obtain a smoothed sequence; The norm normalization function is used to normalize the variance of all data in each smooth sequence, and the normalization result is used as the fluctuation degree of the harmful gas concentration data at the i-th monitoring point.

3. According to claim 1, a method for accurate gas monitoring and analysis in coal mine goaf, characterized in that: The specific method of determining the target monitoring point according to the fluctuation degree of the harmful gas concentration data at each monitoring point includes: If the fluctuation degree of the harmful gas concentration data at the ith monitoring point is greater than a preset first threshold, the ith monitoring point is used as a target monitoring point.

4. The method for accurate gas monitoring and analysis in coal mine goaf according to claim 1, characterized in that: The specific method of determining the weights between nodes includes: The distance between nodes and the out-degree of each node in the positive direction of the directed graph of the coal mine goaf is obtained, and the product of the distance between any node and the next node in the positive direction and the out-degree of any node in the positive direction is used as the weight between the any node and the next node.

5. The method for accurate gas monitoring and analysis in coal mine goaf according to claim 1, characterized in that: The specific method of determining the optimal path from the air inlet to the target monitoring point and the optimal path from the target monitoring point to the air outlet includes: Take any air inlet as the starting node, count all different paths from the jth target monitoring point to the starting node in the directed graph, obtain the updated distance of each path according to the weights between the nodes on each path, and take the path corresponding to the minimum updated distance of all paths as the optimal path from any air inlet to the jth target monitoring point; According to the method for obtaining the best path from each air inlet to each target monitoring point, the best path from each target monitoring point to each air outlet is obtained.

6. A method for accurate gas monitoring and analysis in coal mine goaf according to claim 5, characterized in that: The specific method for obtaining the updated distance of the path is: The sum of the weights between all adjacent nodes on each path is recorded as the updated distance of each path.

7. The method for accurate gas monitoring and analysis in coal mine goaf according to claim 1, characterized in that: The specific method of determining the final optimal path passing through the target monitoring point includes: The best path from the air inlet to the jth target monitoring point is recorded as the P path, and the best path from the jth target monitoring point to the air outlet is recorded as the Q path. In the directed graph, straight line fitting is performed on all nodes on the pth P path and all nodes on the qth Q path, respectively, to obtain the fitting straight line corresponding to the pth P path and the fitting straight line corresponding to the qth Q path, and the maximum angle θ formed by the fitting straight line corresponding to the pth P path and the fitting straight line corresponding to the qth Q path is calculated. p,q The path formed by the P path and the Q path corresponding to the maximum value of the maximum angle formed by the fitting straight lines corresponding to all P paths and the fitting straight lines corresponding to all Q paths is recorded as the final optimal path passing through the jth target monitoring point.

8. The method for accurate gas monitoring and analysis in coal mine goaf according to claim 1, characterized in that: The specific method of determining the reference monitoring point of the target monitoring point according to the final optimal path passing through the target monitoring point includes: All monitoring points on the final optimal path passing through the j-th target monitoring point are obtained, and all monitoring points except the j-th target monitoring point are recorded as reference detection points.

9. The method for accurate gas monitoring and analysis in coal mine goaf according to claim 1, characterized in that: The specific method of determining the updated harmful gas concentration data of the target monitoring point includes: Get the distance x from the jth target monitoring point to the air outlet w , find the horizontal coordinate x on the distance-concentration change curve of the reference monitoring point w The corresponding ordinate y w , then we get y w , recorded as the updated monitoring data of the jth target monitoring point at the current moment.

10. A method for accurate gas monitoring and analysis in coal mine goaf according to claim 9, characterized in that: The specific method for obtaining the distance-concentration variation curve of the reference monitoring point is: In the final optimal path passing through the jth target monitoring point, obtain the distance x from the vth reference monitoring point to the air inlet. v And the harmful gas concentration data y of the vth reference monitoring point at the current moment v , get the coordinates of the vth reference monitoring point (x v ,y v ), the coordinates of all reference monitoring points are mapped to the rectangular coordinate system, and the least squares method is used to perform curve fitting on all data points on the rectangular coordinate system to obtain the distance-concentration change curve of the reference monitoring point.

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