A method, system and storage medium for locating earthquake source

Abstract

The present invention relates to the technical field of train safety monitoring, and discloses a method, system and storage medium for locating a source of earthquake, wherein the method determines the optimal path of each grid point in M ​​grid points from N sensors; takes the optimal path as the transmission path, calculates the theoretical arrival time difference of the signal reaching the N sensors at different wave speeds; then separates the target frequency signal from the actual impact signal, and calculates the actual arrival time difference of the target frequency signal reaching the N sensors; finally, determines the location of the source of earthquake according to the theoretical arrival time difference and the actual arrival time difference. Accurate positioning can be performed for various complex structures; path optimization based on grid points can reduce the influence of obstacles; calculating the actual arrival time difference based on the target frequency signal can overcome the dispersion problem of the impact signal in the actual arrival time difference extraction, thereby extracting an accurate actual arrival time difference, so as to further achieve accurate positioning of the source of earthquake for various complex structures of high-speed railways.

Description

Technical Field

[0001] The present invention relates to the technical field of train safety monitoring, and in particular to a source locating method, system and storage medium. Background Art

[0002] With the rapid development of high-speed rail technology, the issue of high-speed rail driving safety has also received great attention. Since high-speed rail runs in complex environments for a long time, the various structures of high-speed rail are often hit by foreign objects such as gravel, ice and snow. For alloy materials, there is a great possibility of microscopic damage after being hit by foreign objects. For composite materials, it is easy to cause serious damage such as internal delamination after being hit by foreign objects. Once the structure is damaged, the damage will expand rapidly under the strong load of the high-speed rail, and eventually cause serious safety accidents. Therefore, impact damage monitoring of various high-speed rail structures has become the research focus of high-speed rail safety monitoring.

[0003] At present, the commonly used monitoring methods are implemented through non-destructive testing or Lamb wave impact damage positioning methods. Conventional non-destructive testing methods mostly require shutdown testing, and the testing equipment is complex and time-consuming, which is not suitable for real-time monitoring of various high-speed rail structures. Most of the existing Lamb wave impact damage positioning methods require the pre-measurement of the Lamb wave velocity in the structure and use the wave velocity as an important parameter for positioning. For example, wavelet transform is used to extract the accurate time difference of impact signal, and the measured wave velocity and dispersion curve are used to locate multiple impact points in the composite material structure through the time reversal method. However, this method requires pre-testing the speed of Lamb waves of different frequencies in the structure, and the preparation work is complicated; alternatively, a plum blossom-shaped dense sensor array is used for impact positioning, and the wave velocity is automatically calculated by the signal time difference inside the dense sensor array, and then the wave velocity is used as a parameter for impact positioning. However, since the sensors for measuring the wave velocity are densely distributed, there may be large errors in the wave velocity measurement, making it difficult to ensure the accuracy of impact positioning; alternatively, a special sensor array is used for signal monitoring, and it is believed that the impact signal propagates in a circle after being excited from the impact point. The impact point can be located by locating the center of the circle through a special sensor array and an algorithm. This method does not require pre-measurement of the wave velocity, but is only suitable for structures with simple shapes and no obstacles inside. Since the shapes of high-speed rail structures are complex and most of them have hollow parts such as holes, and Lamb waves can only bypass these parts after encountering them, most of the existing impact damage location methods are not suitable for the various complex structures of high-speed rail, and cannot achieve accurate positioning of the earthquake source for the various complex structures of high-speed rail. Summary of the invention

[0004] The present invention provides a method, system and storage medium for locating a seismic source, so as to solve the problem that most existing methods for locating impact damage are not suitable for various complex structures of high-speed railways and cannot accurately locate the seismic source for various complex structures of high-speed railways.

[0005] In order to achieve the above object, the present invention is implemented by the following technical solutions:

[0006] In a first aspect, the present invention provides a method for locating a seismic source, which is applied to a seismic source locating system, wherein the seismic source locating system comprises N sensors arranged at a target structure of a train, where N is a positive integer, and comprises:

[0007] Dividing the target structure into M grid points according to a preset grid size, and determining an optimal path from each of the M grid points to the N sensors;

[0008] Taking the optimal path as the transmission path, calculating the theoretical time difference of the signal reaching the N sensors at different wave speeds;

[0009] Separating the target frequency signal from the actual impact signal, and calculating the actual arrival time difference of the target frequency signal at the N sensors;

[0010] The earthquake source position is determined according to the theoretical arrival time difference and the actual arrival time difference.

[0011] Optionally, determining an optimal path from each grid in the M grids to the N sensors includes:

[0012] Determine the obstacle position, and record the non-obstruction area grid points among the M grid points as the first marking grid points according to the obstacle position, and record the obstacle area grid points as the second marking grid points, to obtain a grid marking matrix;

[0013] Traverse and visit the first marked grid point, set the target grid point to be directly connected to the grid points of the surrounding three layers, take the sensor position as the starting point, take the starting point and the target grid point as a set S, and take the remaining grid points in the first marked grid point except the set S as a set T; the target grid point is any grid point of the first marked grid point;

[0014] Move the grid point Vi adjacent to the target grid point into the set S, and calculate the distance Di+1 from the grid point Vi+1 directly connected to Vi to the starting point. If a grid point has multiple distances to the starting point in one update, take the shortest distance.

[0015] Move the grid point Vi+1 from the set T to the set S, calculate the distance Di+2 from the grid point Vi+2 directly connected to Vi+1 to the starting point, and so on, until all grid points have been moved from the set T to the set S, so as to obtain the optimal path from each grid point in the first marked grid point to the N sensors.

[0016] Optionally, separating the target frequency signal from the actual impact signal includes:

[0017] The target frequency signal in the actual impulse signal is separated by short-time Fourier transform, wherein the following formula is satisfied when the short-time Fourier transform is used for separation:

[0018]

[0019] In the formula, STFT x (t,f) represents the target frequency signal, g(τ-t) represents the time window function, x(τ) is the received signal, f represents the frequency, t represents the time, j represents the imaginary number, and τ is the intermediate parameter.

[0020] Optionally, calculating the actual arrival time difference of the target frequency signal at the N sensors includes:

[0021] The time waveform of each sensor receiving the target frequency signal is extracted, and the arrival time of the first peak point in the waveform is calculated as the actual arrival time difference of the impulse signal at different sensors.

[0022] Optionally, determining the earthquake source location according to the theoretical arrival time difference and the actual arrival time difference comprises:

[0023] Calculate the degree of deviation between the theoretical arrival time difference and the actual arrival time difference;

[0024] The grid point with the smallest deviation is taken as the earthquake source location.

[0025] Optionally, the calculation of the deviation between the theoretical arrival time difference and the actual arrival time difference satisfies the following formula:

[0026] D xyc =∑(Δt xyc -ΔT0) 2 ;

[0027] Where D xyc Indicates the degree of deviation between the grid point and the impact point, Δt xyc It represents the theoretical arrival time difference under different wave speeds, and ΔT0 represents the actual arrival time difference.

[0028] Optionally, the preset grid size is 1 mm.

[0029] In a second aspect, the present application provides a seismic source locating system, comprising N sensors disposed at a target structure of a train and a processing center, where N is a positive integer, the processing center is connected to the N sensors, and the processing center is used to:

[0030] Dividing the target structure into M grid points according to a preset grid size, and determining an optimal path from each of the M grid points to the N sensors;

[0031] Taking the optimal path as the transmission path, calculating the theoretical time difference of the signal reaching the N sensors at different wave speeds;

[0032] Separating the target frequency signal from the actual impact signal, and calculating the actual arrival time difference of the target frequency signal at the N sensors;

[0033] The earthquake source position is determined according to the theoretical arrival time difference and the actual arrival time difference.

[0034] In a third aspect, the present application provides a source locating system, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method described in the first aspect when executing the computer program.

[0035] In a fourth aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method steps described in the first aspect.

[0036] Beneficial effects:

[0037] The earthquake source positioning method provided by the present invention first determines the optimal path of each grid point in M ​​grid points from N sensors; takes the optimal path as the transmission path, and calculates the theoretical arrival time difference of the signal reaching N sensors at different wave speeds; then separates the target frequency signal from the actual impact signal, and calculates the actual arrival time difference of the target frequency signal reaching N sensors; finally, determines the earthquake source position according to the theoretical arrival time difference and the actual arrival time difference. In this way, the target structure is divided into M grid points, and accurate positioning can be performed for various complex structures; path optimization based on grid points can reduce the influence of obstacles; calculating the actual arrival time difference based on the target frequency signal can overcome the dispersion problem of the impact signal in the actual arrival time difference extraction, thereby extracting an accurate actual arrival time difference, so as to further achieve accurate positioning of the earthquake source for various complex structures of high-speed railways. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A flow chart of a method for locating a seismic source according to a preferred embodiment of the present invention;

[0039] Figure 2 A schematic diagram of an impact signal according to a preferred embodiment of the present invention;

[0040] Figure 3 1 is a time-frequency analysis diagram of an impulse signal according to a preferred embodiment of the present invention, wherein (a) is a schematic diagram of SFFT of an impulse signal, and (b) is a schematic diagram of a 50kHz frequency component of an impulse signal;

[0041] Figure 4 Schematic diagram of simulation experiment of a preferred embodiment of the present invention, wherein (a) is a schematic diagram of plane deployment of simulation structure, and (b) is a schematic diagram of simulation model;

[0042] Figure 5 It is a schematic diagram of each received signal when simulating impact at (250, 325) of a preferred embodiment of the present invention;

[0043] Figure 6 A schematic diagram of a simulation impact positioning result of a preferred embodiment of the present invention;

[0044] Figure 7 A schematic diagram of an aluminum alloy test piece and an impact hammer according to a preferred embodiment of the present invention;

[0045] Figure 8 Schematic diagram of receiving signals of each sensor when impact occurs at (285, 215) in a preferred embodiment of the present invention, wherein (a) is a schematic diagram of receiving signals of sensors 1, 3, 5, and 7, and (b) is a schematic diagram of receiving signals of sensors 2, 4, 6, and 8;

[0046] Fig. 9 The signal spectrum received by sensor 1 when impacted at (285, 215) in the preferred embodiment of the present invention;

[0047] Fig.10 50kHz components in the signals received by each sensor when impact occurs at (285, 215) in a preferred embodiment of the present invention, wherein (a) is a schematic diagram of the 50kHz components in the signals received by sensors 1, 3, 5, and 7, and (b) is a schematic diagram of the 50kHz components in the signals received by sensors 2, 4, 6, and 8;

[0048] Fig.11 Schematic diagrams of the degree of deviation of each grid of the preferred embodiment of the present invention, wherein (a) is a schematic diagram of the impact at (135, 190), (b) is a schematic diagram of the impact at (214, 272), (c) is a schematic diagram of the impact at (250, 250), (d) is a schematic diagram of the impact at (250, 325), and (e) is a schematic diagram of the impact at (285, 215). DETAILED DESCRIPTION

[0049] The technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the usual meanings understood by persons with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "one" do not indicate quantity restrictions, but indicate the existence of at least one. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship also changes accordingly.

[0051] It should be pointed out that due to the complex operating environment of high-speed rail, foreign objects often hit various structures. Such impact events can easily cause structural damage and threaten driving safety. Therefore, it is very necessary to monitor impact events in various structures of high-speed rail. In the traditional Lamb wave impact positioning method, it is often necessary to measure the wave velocity in advance, and assume that there are no obstacles such as holes and holes in the structure, and use the signal to time difference combined with the ellipse method, triangulation method and other methods for positioning. However, in actual situations, it is difficult to accurately measure the wave velocity of each structure of the high-speed rail, and the shapes of each structure of the high-speed rail are irregular. The use of traditional methods for positioning will inevitably lead to large errors. Based on this, the present application provides a source positioning method.

[0052] See also Figure 1 The embodiment of the present application provides a source positioning method, which is applied to a source positioning system. The source positioning system includes N sensors arranged at a target structure of a train, where N is a positive integer, including:

[0053] Divide the target structure into M grid points according to the preset grid size, and determine the optimal path from each grid point in the M grid points to the N sensors;

[0054] Taking the optimal path as the transmission path, calculate the theoretical time difference of the signal reaching N sensors at different wave speeds;

[0055] Separate the target frequency signal from the actual impact signal, and calculate the actual arrival time difference of the target frequency signal at N sensors;

[0056] The earthquake source location is determined based on the theoretical arrival time difference and the actual arrival time difference.

[0057] In this embodiment, the target structure refers to a structure of a part of the high-speed railway that is impacted.

[0058] The target structure is gridded. The grid size determines the positioning accuracy to a certain extent. However, if the grid size is too small, the computational cost will be too high and no obvious positioning accuracy benefit will be brought. Therefore, the grid size needs to be determined by comprehensively considering the positioning accuracy and computational cost. In this embodiment, the preset grid size can be 1 mm. This is only an example and is not limited here. In other feasible embodiments, the preset grid size can also be adjusted to a certain extent.

[0059] The target frequency signal may be 50 kHz.

[0060] The above-mentioned earthquake source location method first determines the optimal path from each grid point in M ​​grid points to N sensors; takes the optimal path as the transmission path, and calculates the theoretical arrival time difference of the signal reaching N sensors at different wave speeds; then separates the target frequency signal from the actual impact signal, and calculates the actual arrival time difference of the target frequency signal reaching N sensors; finally, determines the earthquake source position based on the theoretical arrival time difference and the actual arrival time difference. In this way, the target structure is divided into M grid points, and accurate positioning can be performed for various complex structures; path optimization based on grid points can reduce the impact of obstacles; calculating the actual arrival time difference based on the target frequency signal can overcome the dispersion problem of the impact signal in the actual arrival time difference extraction, thereby extracting accurate actual arrival time difference, so as to further achieve accurate positioning of the earthquake source for various complex structures of high-speed rail.

[0061] Optionally, determining an optimal path from each of the M grids to the N sensors includes:

[0062] Determine the obstacle position, and record the non-obstruction area grid points among the M grid points as the first marking grid points according to the obstacle position, and record the obstacle area grid points as the second marking grid points, to obtain a grid marking matrix;

[0063] Traverse and visit the first marked grid point, set the target grid point to be directly connected to the grid points of the surrounding three layers, take the sensor position as the starting point, take the starting point and the target grid point as set S, and take the remaining grid points in the first marked grid point except set S as set T; the target grid point is any grid point of the first marked grid point;

[0064] Move the grid point Vi adjacent to the target grid point into the set S, and calculate the distance Di+1 from the grid point Vi+1 directly connected to Vi to the starting point. If a grid point has multiple distances to the starting point in one update, take the shortest distance.

[0065] Move the grid point Vi+1 from set T to set S, calculate the distance Di+2 from the grid point Vi+2 directly connected to Vi+1 to the starting point, and so on, until all grid points have been moved from set T to set S, to obtain the optimal path from each grid point in the first marked grid point to the N sensors.

[0066] In this optional implementation, Di+1=Di+di,i+1, wherein Di is the distance from Vi to V0, and di,i+1 represents the distance between Vi and Vi+1.

[0067] By setting each grid point to be directly connected to the grid points of the surrounding three layers, that is, directly connected to the surrounding 48 grid points, the number of non-repeated search directions is 32, and the search directions are increased, which can improve the path optimization accuracy.

[0068] In this embodiment, only the grid points marked as the first mark are visited during path optimization, so that obstacles can be avoided and impact positioning can be achieved in a structure containing obstacles without the need to measure the wave velocity in advance.

[0069] Optionally, separating the target frequency signal from the actual impact signal includes:

[0070] The target frequency signal in the actual impulse signal is separated by short-time Fourier transform, wherein the following formula is satisfied when the short-time Fourier transform is used for separation:

[0071]

[0072] Where, STFT x (t,f) represents the target frequency signal, g(τ-t) represents the time window function, x(τ) is the received signal, f represents the frequency, t represents the time, j represents the imaginary number, and τ is the intermediate parameter.

[0073] It should be noted that the impact of foreign objects will generate a broadband impact signal in the structure. This impact signal will propagate in the structure in the form of Lamb waves. The group velocity and phase velocity of different frequency components of Lamb waves are quite different, which will cause serious dispersion. In addition, there are multiple mode aliasing phenomena, which makes it difficult to directly obtain the accurate arrival time difference based on the timing signal received by the sensor. The impact signal is Figure 2 shown.

[0074] In this optional implementation, in order to avoid interference of the above-mentioned various factors on the extraction of the arrival time difference, it is necessary to perform time-frequency analysis on the impulse signal, separate the specific frequency signal, and calculate the accurate arrival time difference.

[0075] Optionally, calculating the actual arrival time difference of the target frequency signal at the N sensors includes:

[0076] The time waveform of each sensor receiving the target frequency signal is extracted, and the arrival time of the first peak point in the waveform is calculated as the actual arrival time difference of the impulse signal at different sensors.

[0077] Specifically, this embodiment uses short-time Fourier transform (SFFT) to perform time-frequency analysis. The arrival time of different frequencies can be obtained through SFFT, such as Figure 3 (a) shows Figure 2 SFFT of the impulse signal. Select the 50kHz frequency distribution in time as follows Figure 3 (b) is shown as 50kHz. By extracting the time waveform of the frequency component of different sensor signals and calculating the arrival time of the first peak point, the arrival time difference of the impact signal at different sensors can be accurately obtained.

[0078] Optionally, determining the earthquake source location according to the theoretical arrival time difference and the actual arrival time difference includes:

[0079] Calculate the degree of deviation between the theoretical arrival time difference and the actual arrival time difference;

[0080] The grid point with the smallest deviation is taken as the earthquake source location.

[0081] In one example, the following formula is satisfied when calculating the degree of deviation between the theoretical arrival time difference and the actual arrival time difference:

[0082] D xyc =∑(Δt xyc -ΔT0) 2 ;

[0083] Where D xyc Indicates the degree of deviation between the grid point and the impact point, Δt xyc It represents the theoretical arrival time difference under different wave speeds, and ΔT0 represents the actual arrival time difference.

[0084] It should be noted that the formula mentioned in this application is only a mathematical relationship or expression that it satisfies, and different transformations may be made in different examples.

[0085] In this embodiment, the shortest distance from each grid point to the starting point can be used to calculate the distance difference L from each sensor at a known position to a certain grid point, and the theoretical arrival time difference Δt under different wave speeds can be calculated using different wave speeds C. xyc , combined with the actual arrival time difference ΔT0, the deviation between the theoretical arrival time difference and the actual arrival time difference of each grid point can be calculated. The summation represents the comprehensive consideration of the deviation between the arrival time differences of different sensor combinations. xyc The smallest grid point is used as the impact damage diagnosis point to achieve accurate positioning of the earthquake source.

[0086] Furthermore, finite element simulation and physical tests can be used to verify the feasibility of this method. When the positioning error of this method is within the threshold, it is confirmed to be feasible. When the positioning error of this method exceeds the threshold, each calculation step is adjusted and optimized to further improve the accuracy of the above-mentioned source positioning.

[0087] Among them, the impact positioning verification method based on finite element simulation is as follows:

[0088] Finite element simulation is used to verify the impact location method proposed in this paper. Abaqus CAE is used as the simulation software. The simulation model size is 500mm*500mm*2mm, the material density is 2780kg / m3, the elastic modulus is 27GPa, and the Poisson's ratio is 0.33. Seven holes with a diameter of 20mm are set on the model as obstacles, and 8 signal receiving points are set as follows: Figure 4 As shown in (a), the simulation model is Figure 4 (b) Figure 4 In (a), the coordinate origin is the lower left corner, and the coordinates of the obstacle and the signal receiving point are shown in Table 1.

[0089] Table 1 Simulated obstacles and sensor locations

[0090]

[0091] The simulation material parameters use concentrated stress perpendicular to the plate surface to simulate the impact signal. The selected concentrated stress signal is a 3.5-cycle sine signal with a 160kHz Hanning window. In order to accurately simulate the propagation process of Lamb waves, the simulation time increment and grid length need to meet certain conditions. First, the grid size must be less than 1 / 10 of the shear wave wavelength in the structure. Secondly, it is required that there are at least 20 time increments in one cycle corresponding to the highest frequency of the simulation signal. Finally, it is required that the distance of the shear wave propagation in one time increment cannot exceed one grid unit. Combined with the above requirements, the simulation grid size is finally determined to be 0.5mm and the time increment is 0.01μs.

[0092] The Lamb wave waveform at each signal receiving point during the simulation is as follows: Figure 5 As shown in Figure 2, the signal receiving point is used as the sensor position, the time difference of the signal arriving at each sensor is extracted, and substituted into the impact damage location method proposed in this paper. Finally, the impact location results are obtained as shown in Table 2 and Figure 6 shown.

[0093] Table 2 Simulation impact positioning coordinates

[0094]

[0095] From the positioning results based on finite element simulation, it can be seen that the impact positioning method in this paper is feasible and can ensure high positioning accuracy.

[0096] Among them, the physical test verification method is as follows:

[0097] A 2mm thick Al2024-T3 plate with a size of 500mm*500mm was used as the experimental piece. The specific structural design and sensor layout were the same as the simulation model mentioned above. Figure 4 (b) is the same, and the impact is simulated by using an impact hammer with an energy of 2J, such as Figure 7 shown.

[0098] Use an impact hammer to impact the test board, use 8 sensors to receive the impact signal, and use a Tektronix oscilloscope to record the data. Since the oscilloscope can only record four sets of waveforms at a time, the sensors are divided into two groups according to the sensor number and receive them separately. The impact signal waveform received by each sensor is recorded as follows: Figure 8 shown.

[0099] Perform Fourier transform analysis on the received signal. Fig. 9 As shown in the figure, it can be seen that the main frequency distribution of the impact signal is between 0 and 60 kHz. The 50 kHz signal component in the impact signal is separated by short-time Fourier transform as shown in Fig.10 As shown, the arrival time difference of the impact signal to each sensor is calculated and substituted into the impact location method of this paper to obtain the deviation degree D of different grid points. xyc like Fig.11 As shown, the cross represents the actual impact position and the minimum deviation degree D xyc The corresponding position is taken as the impact positioning result.

[0100] Search for the minimum deviation D xyc The positioning results of the impact point are shown in Table 3. It can be seen from Table 3 that the positioning results of the physical test are consistent with the actual impact point, and the error is kept within 10mm.

[0101] Table 3 Impact positioning coordinates

[0102]

[0103]

[0104] In summary, this application realizes the optimization of the path from each point inside the structure to the sensor, and uses different wave speeds to calculate the theoretical arrival time difference, and matches the actual arrival time difference with the theoretical arrival time difference to achieve impact positioning. In order to overcome the dispersion problem of the impact signal in the actual arrival time difference extraction, this study uses short-time Fourier transform to extract specific frequency components, thereby extracting accurate arrival time difference.

[0105] The embodiment of the present application further provides a seismic source positioning system, comprising N sensors disposed at a target structure of a train and a processing center, where N is a positive integer, and the processing center is connected to the N sensors, and the processing center is used to:

[0106] Dividing the target structure into M grid points according to a preset grid size, and determining an optimal path from each of the M grid points to the N sensors;

[0107] Taking the optimal path as the transmission path, calculating the theoretical time difference of the signal reaching the N sensors at different wave speeds;

[0108] Separating the target frequency signal from the actual impact signal, and calculating the actual arrival time difference of the target frequency signal at the N sensors;

[0109] The earthquake source position is determined according to the theoretical arrival time difference and the actual arrival time difference.

[0110] The above-mentioned earthquake source locating system can implement various embodiments of the above-mentioned earthquake source locating method and can achieve the same beneficial effects, which will not be described in detail here.

[0111] The embodiment of the present application also provides a source location system, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above method when executing the computer program. The above source location system can implement various embodiments of the above source location method and achieve the same beneficial effects, which will not be described in detail here.

[0112] The present application also provides a computer-readable storage medium on which a computer program is stored, and when the program is executed by a processor, the method steps described above are implemented. The computer-readable storage medium can implement various embodiments of the above-mentioned source location method and achieve the same beneficial effects, which will not be described in detail here.

[0113] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A method for locating a seismic source, applied to a seismic source locating system, wherein the seismic source locating system comprises N sensors arranged at a target structure of a train, where N is a positive integer, and is characterized in that: include: Dividing the target structure into M grid points according to a preset grid size, and determining an optimal path from each of the M grid points to the N sensors; Taking the optimal path as the transmission path, calculating the theoretical time difference of the signal reaching the N sensors at different wave speeds; Separating the target frequency signal from the actual impact signal, and calculating the actual arrival time difference of the target frequency signal at the N sensors; Determine the earthquake source location according to the theoretical arrival time difference and the actual arrival time difference; Determining the optimal path from each grid in the M grids to the N sensors includes: Determine the obstacle position, and record the non-obstruction area grid points among the M grid points as the first marking grid points according to the obstacle position, and record the obstacle area grid points as the second marking grid points, to obtain a grid marking matrix; Traverse and visit the first marked grid point, set the target grid point to be directly connected to the grid points of the surrounding three layers, take the sensor position as the starting point, take the starting point and the target grid point as a set S, and take the remaining grid points in the first marked grid point except the set S as a set T; the target grid point is any grid point of the first marked grid point; Move the grid point Vi adjacent to the target grid point into the set S, and calculate the distance Di+1 from the grid point Vi+1 directly connected to Vi to the starting point. If a grid point has multiple distances to the starting point in one update, take the shortest distance. Move the grid point Vi+1 from the set T to the set S, calculate the distance Di+2 from the grid point Vi+2 directly connected to Vi+1 to the starting point, and so on, until all the grid points have been moved from the set T to the set S, so as to obtain the optimal path from each grid point in the first marked grid point to the N sensors; Determining the earthquake source location according to the theoretical arrival time difference and the actual arrival time difference comprises: Calculate the degree of deviation between the theoretical arrival time difference and the actual arrival time difference; The grid point with the smallest deviation is taken as the earthquake source location; The calculation of the deviation between the theoretical arrival time difference and the actual arrival time difference satisfies the following formula: D xyc =∑(Δt xyc -ΔT0) 2 ; Where D xyc Indicates the degree of deviation between the grid point and the impact point, Δt xyc It represents the theoretical arrival time difference under different wave speeds, and ΔT0 represents the actual arrival time difference.

2. The earthquake source locating method according to claim 1, characterized in that: The step of separating the target frequency signal from the actual impact signal comprises: The target frequency signal in the actual impulse signal is separated by short-time Fourier transform, wherein the following formula is satisfied when the short-time Fourier transform is used for separation: In the formula, STFT x (t,f) represents the target frequency signal, g(τ-t) represents the time window function, x(τ) is the received signal, f represents the frequency, t represents the time, j represents the imaginary number, and τ is the intermediate parameter.

3. The earthquake source locating method according to claim 2, characterized in that: The calculating the actual arrival time difference of the target frequency signal at the N sensors includes: The time waveform of each sensor receiving the target frequency signal is extracted, and the arrival time of the first peak point in the waveform is calculated as the actual arrival time difference of the impulse signal at different sensors.

4. The earthquake source locating method according to claim 1, characterized in that: The preset grid size is 1 mm.

5. A seismic source locating system, characterized in that: The invention comprises N sensors and a processing center arranged at a target structure of a train, wherein N is a positive integer, the processing center is connected to the N sensors, and the processing center is used for: Dividing the target structure into M grid points according to a preset grid size, and determining an optimal path from each of the M grid points to the N sensors; Taking the optimal path as the transmission path, calculating the theoretical time difference of the signal reaching the N sensors at different wave speeds; Separating the target frequency signal from the actual impact signal, and calculating the actual arrival time difference of the target frequency signal at the N sensors; Determine the earthquake source location according to the theoretical arrival time difference and the actual arrival time difference; Determining the earthquake source location according to the theoretical arrival time difference and the actual arrival time difference comprises: Calculate the degree of deviation between the theoretical arrival time difference and the actual arrival time difference; The grid point with the smallest deviation is taken as the earthquake source location; The calculation of the deviation between the theoretical arrival time difference and the actual arrival time difference satisfies the following formula: D xyc =∑(Δt xyc -ΔT0) 2 ; Where D xyc Indicates the degree of deviation between the grid point and the impact point, Δt xyc It represents the theoretical arrival time difference under different wave speeds, and ΔT0 represents the actual arrival time difference.

6. A seismic source location system, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method described in any one of claims 1 to 4 are implemented.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method steps described in any one of claims 1 to 4 are implemented.

Images