A method for precise gas monitoring and analysis in a coal mine goaf

Abstract

The present invention relates to the field of intelligent control technology, and specifically relates to a method for accurately monitoring and analyzing the gas in the goaf of a coal mine, including: obtaining the sequence of harmful gas concentration data at the monitoring points, determining the target monitoring points according to the fluctuation degree of the monitoring data at each monitoring point, drawing a directed graph of the coal mine goaf, determining the final optimal path passing through each target monitoring point, determining the reference monitoring points of each target monitoring point according to the final optimal path, and determining the updated monitoring data of each target monitoring point according to the monitoring data of the reference monitoring points of each target monitoring point and the distance from the affiliated reference monitoring point to the air inlet. The present invention updates the data of the monitoring points, reduces the monitoring data error caused by sensor distortion, and improves the monitoring accuracy of the sensor.

Description

Technical Field

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

[0002] In a coal mine gob area, 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 their concentrations are 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 at key areas in the coal mine to continuously and real-time monitor the concentrations of dangerous gases in the surrounding environment, promptly detect abnormal changes in gas concentrations, and quickly notify miners and management personnel through an advanced warning system. Once potential hazards are detected, relevant personnel can immediately take necessary emergency measures, such as evacuating personnel, starting the ventilation system, or using inhibitors, thus effectively avoiding the occurrence of dangerous accidents and ensuring the safe operation of the mine.

[0003] Currently, the monitoring of dangerous gases in coal mines mainly relies on various types of sensors. However, the performance of sensors may be affected by various factors, such as environmental temperature, humidity, dust, etc., which may all cause the sensor readings to be distorted. The distorted monitoring data will not only reduce the accuracy of monitoring, but also may delay the response to changes in the concentrations of dangerous gases, increasing the risk of accidents and affecting the control of coal mine safety. Summary of the Invention

[0004] The present invention provides a method for accurately monitoring and analyzing gases in a coal mine gob area to solve the existing problems.

[0005] The method for accurately monitoring and analyzing gases in a coal mine gob area of the present invention adopts the following technical solutions:

[0006] Obtain the sequence of harmful gas concentration data at the monitoring points, obtain the degree of fluctuation of the harmful gas concentration data at each monitoring point, and determine the target monitoring point according to the degree of fluctuation of the harmful gas concentration data at each monitoring point; the sequence of harmful gas concentration data includes the harmful gas concentration data at the current moment.

[0007] Draw a directed graph of the coal mine gob area, 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 points in the coal mine gob area, and the direction from the air inlet to the air outlet in the directed graph is used as the positive direction; according to the weights between the nodes, determine 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.

[0008] Determine the final optimal path passing through the target monitoring point according to the included 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;

[0009] Determine 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.

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

[0011] Use mean filtering to smooth all the data in the harmful gas concentration data sequence of the i-th detection point to obtain a smoothed sequence;

[0012] Use the norm normalization function to normalize the variance of all the data in each smoothed sequence, and use the normalized result as the fluctuation degree of the harmful gas concentration data of the i-th monitoring point.

[0013] Further, the specific method for determining the target monitoring point according to the fluctuation degree of the harmful gas concentration data of each monitoring point includes:

[0014] If the fluctuation degree of the harmful gas concentration data of the i-th monitoring point is greater than a preset first threshold, then take the i-th monitoring point as the target monitoring point.

[0015] Further, the specific method for determining the weight between nodes includes:

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

[0017] Further, the specific method for 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 between the j-th target monitoring point and the starting node in the directed graph, obtain the updated distance of each path according to the weight between nodes on each path, and take the path corresponding to the minimum value among the updated distances of all paths as the optimal path from any air inlet to the j-th target monitoring point;

[0019] According to the obtaining method of the optimal path from each air inlet to each target monitoring point, obtain the optimal path from each target monitoring point to each air outlet.

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

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

[0022] Further, the specific method for determining the final optimal path passing through the target monitoring point includes the following:

[0023] Denote the optimal path from the air inlet to the j-th target monitoring point as the P path, and the optimal path from the j-th target monitoring point to the air outlet as the Q path. In the directed graph, perform linear fitting on all the nodes on the p-th P path and all the nodes on the q-th Q path respectively, to obtain the fitting line corresponding to the p-th P path and the fitting line corresponding to the q-th Q path, and calculate the maximum included angle θ formed by the fitting line corresponding to the p-th P path and the fitting line corresponding to the q-th Q path p,q , and denote the path formed by the P path and the Q path corresponding to the maximum value among the maximum included angles formed by the fitting lines corresponding to all the P paths and the fitting lines corresponding to all the Q paths as the final optimal path passing through the j-th target monitoring point.

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

[0025] Obtain all the monitoring points on the final optimal path passing through the j-th target monitoring point, and denote the monitoring points other than the j-th target monitoring point as the reference detection points.

[0026] Further, the specific method for determining the updated harmful gas concentration data of the target monitoring point includes the following:

[0027] Obtain the distance x from the j-th target monitoring point to the air outlet w , and find the ordinate y corresponding to the abscissa x on the distance-concentration change curve of the reference monitoring point w at this time w , and the obtained y w , which is denoted as the updated monitoring data of the j-th target monitoring point at the current moment.

[0028] Further, the specific method for obtaining the distance-concentration change curve of the reference monitoring point is as follows:

[0029] In the final optimal path passing through the j-th target monitoring point, obtain the distance x from the v-th reference monitoring point to the air inlet v and the harmful gas concentration data y of the v-th reference monitoring point at the current moment v , to obtain the coordinates (x v , yv ) Map the coordinates of all reference monitoring points into a rectangular coordinate system, and use the least squares method to perform curve fitting on all data points in the rectangular coordinate system to obtain the distance-concentration change curve of the reference monitoring points.

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

[0031] The beneficial effects of the technical solution of the present invention are as follows: Obtain the sequence of harmful gas concentration data at the monitoring points, obtain the fluctuation degree of the harmful gas concentration data at each monitoring point, determine the target monitoring point according to the fluctuation degree of the harmful gas concentration data at each monitoring point, which helps to determine the analysis target and narrow the analysis scope. 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 points in the coal mine goaf. The direction from the air inlet to the air outlet in the directed graph is used as the positive direction; According to the weights between the nodes, determine 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, which helps to determine the best path passing through the target monitoring point. According to the included 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, determine the final best path passing through the target monitoring point. According to the final best path passing through the target monitoring point, determine the reference monitoring point of the target monitoring point, which helps to analyze and determine 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, determine the updated harmful gas concentration data of the target monitoring point to accurately monitor the harmful gas in the coal mine goaf, reduce the distortion of the sensor caused by other factors, and improve the monitoring accuracy of the sensor. Description of the Drawings

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0033] Figure 1 It is a flowchart of the steps of a method for precise gas monitoring and analysis in a coal mine goaf according to the present invention;

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

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

[0036] Figure 4 Schematic diagram of the out-degree of nodes in the directed graph of the goaf in coal mines provided by the present invention;

[0037] Figure 5 Schematic diagram of the weights between nodes in the directed graph of the goaf in coal mines provided by the present invention. Specific embodiments

[0038] In order to further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following combines the drawings and preferred embodiments to detail the specific embodiments, structures, features and effects of a method for accurately monitoring and analyzing gas in the goaf of coal mines proposed according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs.

[0040] The following specifically describes the specific solution of a method for accurately monitoring and analyzing gas in the goaf of coal mines provided by the present invention with reference to the drawings.

[0041] Please refer to Figure 1 , which shows a flowchart of the steps of a method for accurately monitoring and analyzing gas in the goaf of coal mines provided by an embodiment of the present invention. The method includes the following steps:

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

[0043] It should be noted that the distortion of the sensor is manifested as the output value fluctuating randomly due to external factor interference, resulting in large fluctuations in the data monitored at each monitoring point. Therefore, the monitoring points with sensor distortion can be determined according to 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 a method for accurately monitoring and analyzing gas in the goaf of coal mines proposed in this embodiment, it is first necessary to determine the target monitoring point. The specific process is as follows:

[0045] First, obtain the harmful gas concentration data monitored hourly at any monitoring point at the current moment and within the 24 hours before the current moment. Take the set of the said data as the monitoring data sequence of this monitoring point. Set a window with a length of A. Taking any data in the data sequence of any monitoring point as the center, take the mean value of all the data within the window where the data is located as the value after smoothing this data. Thus, use the mean filter to smooth all the data in the harmful gas concentration data sequence of the i-th detection point. Denote the smoothed monitoring data sequence as the smoothed sequence. This is a well-known technique.

[0046] Then, use the norm normalization function to normalize the variance of all the data in each smoothed sequence. Take the result of the said normalization as the fluctuation degree of the harmful gas concentration data of the i-th monitoring point, denoted as Tp i , calculate the fluctuation degree of the harmful gas concentration data of all the monitoring points. Preset a first threshold. If Tp i is greater than the preset first threshold, take the i-th monitoring point as the monitoring point with sensor distortion, that is, the target monitoring point.

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

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

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

[0050] Step S002: Draw a directed graph of the goaf of the coal mine. 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, road junction and monitoring point of the goaf of the coal mine. In the directed graph, the direction from the air inlet to the air outlet is taken as the positive direction; according to the weights between the nodes, determine 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.

[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 gob area. It transports fresh air from the air inlet to the gob area and discharges the waste gas and harmful gases out of the mine through the air outlet. Therefore, the data monitored at the monitoring points in the same direction has a certain correlation. Under ideal conditions, the correlation of the data monitored at the monitoring points on the straight-line distance from the air inlet to the air outlet is the strongest. However, the path structure of the gob working face in an actual coal mine is complex, with multiple branch points, which affects the diffusion of harmful gases in the gob area. Therefore, the optimal path from the target monitoring point to the air outlet is determined according to the distance between the monitoring points in the coal mine gob area and the number of detection points.

[0052] Step (2.1), draw a directed graph of the coal mine gob area, 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, intersections, and monitoring points in the coal mine gob area. The direction from the air inlet to the air outlet in the directed graph 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 at the monitoring point. The longer the path between the air inlet and the monitoring point, the worse the correlation of the data monitored at the monitoring points on this path. At the same time, the number of intersection branch points on the path will also affect the correlation of the data monitored at the monitoring points passing through this intersection. The more the number of intersection branch points on the path, the wider the diffusion range of the gas passing through this path, and the worse the correlation of the data monitored at the monitoring points on this path. Therefore, the weight size between the nodes is determined according to the distance between two adjacent nodes in the directed graph and the number of intersections on the positive direction of the node.

[0054] First, regard the air inlet, air outlet, intersections, and monitoring points in the coal mine gob area as nodes, and take the direction from the air inlet to the air outlet as the positive direction. All nodes can form a directed graph, as Figure 2 shown in the example diagram of the directed graph, where there are multiple air inlets and air outlets.

[0055] Then, obtain the distances between the nodes in the positive direction of the directed graph of the coal mine gob area and the out-degree of each node. The out-degree of each node is the number of edges starting from each node in the positive direction. Use the out-degree of each node in the positive direction to represent the number of branch points of each intersection in the positive direction. Multiply the distance between any node and the next node in the positive direction by the out-degree of any node in the positive direction as the weight between the any node and the next node.

[0056] It should be noted that the smaller the distance between any node on the positive direction of the directed graph and the next node, and the smaller the out-degree of the said any node, the smaller the weight between the said any node and the next node, and the stronger the correlation between the monitoring data of the monitoring points passing through this node. On the contrary, it is weaker. Among them, Figure 3 、 Figure 4 and Figure 5 reflect all the paths from the air inlet A to the target monitoring point F. The values on the edges between the nodes A, B, C, D, E, and F respectively represent the distance, out-degree, and weight.

[0057] Step (2.2), determine 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 according to the weights between the nodes.

[0058] It should be noted that in this embodiment, through the idea of the greedy strategy and breadth-first traversal, each time the node with the smallest weight in the current path is selected for expansion to ensure 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, take any air inlet as the starting node, count all different paths between the jth target monitoring point in the directed graph and the starting node, and record the sum value of the weights between all adjacent nodes on each path as the updated distance of each path. The path corresponding to the minimum value among the updated distances of all paths is used as the best path from the starting node to the jth target monitoring point.

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

[0061] Then, according to the obtaining method of 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 best path from the air inlet to the target monitoring point and the best path from the target monitoring point to the air outlet are obtained through the above method.

[0063] Step S003, determine the final best path passing through the target monitoring point according to the included 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.

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

[0065] Specifically, first, record the optimal path from the air inlet to the j-th target monitoring point as the P path, and record the optimal path from the j-th target monitoring point to the air outlet as the Q path. In the directed graph, perform linear fitting on all the nodes on the p-th P path and all the nodes on the q-th Q path respectively, obtain the fitting straight line corresponding to the p-th P path and the fitting straight line corresponding to the q-th Q path, and calculate the maximum included angle θ formed by the fitting straight line corresponding to the p-th P path and the fitting straight line corresponding to the q-th Q path. p,q The path composed of the P path and the Q path corresponding to the maximum value among the maximum included angles formed by all the fitting straight lines corresponding to the P paths and all the fitting straight lines corresponding to the Q paths is recorded as the final optimal path passing through the j-th target monitoring point.

[0066] It should be noted that if there are multiple maximum values among the maximum included angles, any one of them can be selected for analysis.

[0067] It should be noted that the included angle θ formed by the p-th P path and the q-th Q path. p,q The larger the included angle is, the more the path formed by the corresponding P path and Q path tends to be a straight line, indicating that the correlation of the data monitored by the monitoring points on the path is higher. On the contrary, the smaller the included angle is.

[0068] Then, obtain all the monitoring points on the final optimal path passing through the j-th target monitoring point, and record the monitoring points other than the j-th target monitoring point as reference detection points.

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

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

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

[0072] Specifically, first, in the final optimal path passing through the j-th target monitoring point, obtain the distance x from the v-th reference monitoring point to the air inlet v and the concentration data y of harmful gases at the v-th reference monitoring point at the current moment v , to obtain the coordinates (x v , y v ) of the v-th reference monitoring point. Map the coordinates of all reference monitoring points into a rectangular coordinate system, and use the least squares method to perform curve fitting on all data points in the rectangular coordinate system to obtain the distance-concentration change curve of the reference monitoring points. 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 concentration data of harmful gases at the reference monitoring point at the current moment.

[0073] Then, obtain the distance x from the j-th target monitoring point to the air outlet w , and find the corresponding ordinate y w when the abscissa is x w on the distance-concentration change curve of the reference monitoring points. At this time, the obtained y w is the updated monitoring data of the j-th target monitoring point at the current moment.

[0074] So far, this embodiment is completed.

[0075] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for precise gas monitoring and analysis in a goaf of a coal mine, characterized in that, The method includes the following steps: Obtain the sequence of harmful gas concentration data at the monitoring points, obtain the fluctuation degree of the harmful gas concentration data at each monitoring point, and determine the target monitoring point according to the fluctuation degree of the harmful gas concentration data at each monitoring point; the sequence of harmful gas concentration data includes the harmful gas concentration data at the current moment; Draw a directed graph of the goaf in the coal mine, 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 points in the goaf of the coal mine, and the direction from the air inlet to the air outlet in the directed graph is taken as the positive direction; 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; Determine the final optimal path passing through the target monitoring point according to the included 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; Determine 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; The specific method included in determining the weights between the nodes is as follows: Obtain the distances between the nodes in the positive direction of the directed graph of the goaf in the coal mine and the out-degree of each node, and take 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 as the weight between the any node and the next node; The specific method included in 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 is as follows: Taking any air inlet as the starting node, count all different paths between the th target monitoring point and the starting node in the directed graph. According to the weights between nodes on each path, obtain the updated distance of each path. Take the path corresponding to the minimum value among the updated distances of all paths as the best path from any air inlet to the th target monitoring point; Obtain the optimal path from each target monitoring point to each air outlet according to the obtaining method of the optimal path from each air inlet to each target monitoring point; The specific obtaining method of the updated distance of the path is as follows: Record the sum of the weights between all adjacent nodes on each path as the updated distance of each path; The specific method included in determining the final optimal path passing through the target monitoring point is as follows: The best path from the air inlet to the th target monitoring point is denoted as Path, and the best path from the th target monitoring point to the air outlet is denoted as Path. In the directed graph, for all nodes on the th Path and all nodes on the th Path, perform linear fitting to obtain the fitting line corresponding to the th Path and the fitting line corresponding to the th Path. Calculate the maximum included angle th formed by the fitting line corresponding to the th Path and the fitting line corresponding to the Path. Among the maximum included angles formed by all fitting lines corresponding to all Paths and all fitting lines corresponding to all Paths, the Path and the Path that form the maximum value are denoted as the final best path passing through the th target monitoring point.

2. The gas precise monitoring and analysis method for a coal mine gob area according to claim 1, characterized in that The specific method included in obtaining the fluctuation degree of the harmful gas concentration data at each monitoring point is as follows: Use mean filtering to smooth all the data in the harmful gas concentration data sequence of the th detection point to obtain a smoothed sequence; Use the norm normalization function to normalize the variance of all data in each smoothed sequence, and take the normalized result as the degree of fluctuation of the harmful gas concentration data at the th monitoring point.

3. The method for precise monitoring and analysis of gas in a coal mine goaf according to claim 1, characterized in that, The specific method included in determining the target monitoring point according to the fluctuation degree of the harmful gas concentration data at each monitoring point is as follows: If the fluctuation degree of the harmful gas concentration data at the th monitoring point is greater than the preset first threshold, then the th monitoring point is taken as the target monitoring point.

4. The gas precise monitoring and analysis method for a coal mine gob area according to claim 1, characterized in that, The specific method included in determining the reference monitoring point of the target monitoring point according to the final optimal path passing through the target monitoring point is as follows: Obtain all the monitoring points on the final optimal path passing through the th target monitoring point, and mark all the monitoring points except the th target monitoring point as reference detection points.

5. The gas precise monitoring and analysis method for a coal mine goaf according to claim 1, characterized in that The specific method included in determining the updated harmful gas concentration data of the target monitoring point is as follows: Obtain the distance from the th target monitoring point to the air outlet , and find the ordinate corresponding to the abscissa of on the distance-concentration change curve of the reference monitoring point . At this time, the obtained is recorded as the updated monitoring data of the th target monitoring point at the current moment.

6. The gas precise monitoring and analysis method for a coal mine gob area according to claim 5, characterized in that The specific obtaining method of the distance-concentration change curve of the reference monitoring point is as follows: In the final optimal path passing through the th target monitoring point, obtain the distance from the th reference monitoring point to the air inlet and the concentration data of harmful gases at the th reference monitoring point at the current moment , and obtain the coordinates of the th reference monitoring point ( ). Map the coordinates of all reference monitoring points into a rectangular coordinate system, and use the least squares method to perform curve fitting on all data points in the rectangular coordinate system to obtain the distance-concentration change curve of the reference monitoring points.

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