Roadbed cavity detection method and device based on vehicle vibration signals and storage medium

Abstract

The invention provides a roadbed cavity detection method and device based on vehicle vibration signals and a storage medium, and the method comprises the steps: installing at least three acceleration sensors on a vehicle, and collecting vibration signals in a vertical direction and a horizontal direction when the vehicle runs on a to-be-detected road section in real time; the vibration signals are analyzed, wave velocity and reflection intensity characteristics are extracted, and a normal roadbed and a roadbed with a cavity are distinguished; for the roadbed with the cavity, vibration signals are received through a plurality of acceleration sensors, and the position of the cavity is determined. Special detection vehicles and equipment are not needed, and only a sensor needs to be installed on an existing vehicle, so that the detection cost is greatly reduced; the method is not only suitable for roadbed cavity detection of various types of roads such as expressways and urban roads, but also can be applied to monitoring of other traffic infrastructures such as railways and bridges, and has wide applicability.

Description

Technical Field

[0001] The present invention relates to the technical field of road detection, and particularly to a method, device and storage medium for detecting subgrade cavities based on vehicle vibration signals. Background Art

[0002] Subgrade cavities are an important threat to the safety of road structures, which are mainly formed due to the physical or chemical loss of internal materials of the subgrade, uneven settlement of the foundation, and defects in the compaction process during the construction stage. Specifically, under the action of groundwater level changes, rainwater infiltration or chemical erosion, the subgrade filler will gradually be lost, resulting in the formation of voids inside; at the same time, if the compaction is insufficient during construction or the bearing capacity distribution of the foundation is uneven, local settlement is likely to occur under the long-term action of vehicle loads, further exacerbating the expansion of the cavities. Such cavities will not only weaken the overall bearing capacity of the subgrade, but also may cause disasters such as road surface cracking and collapse. Especially under heavy rain or heavy traffic conditions, the risk of structural instability in the cavity area increases significantly, seriously threatening driving safety and shortening the service life of the road.

[0003] Currently, the detection technologies for subgrade cavities mainly rely on the core sampling method and ground penetrating radar (GPR) detection. The core sampling method extracts subgrade samples through drilling to directly observe the internal state, but the drilling process will damage the road surface structure, and it can only reflect the local point information, making it difficult to achieve large-scale continuous detection; although ground penetrating radar can indirectly identify underground anomalies through electromagnetic wave reflection images, its equipment purchase and maintenance costs are high, and the detection accuracy is easily affected by environmental factors such as soil moisture and metal interference. The interpretation of cavity boundaries depends on the operator's experience, with a large subjective error. In addition, the above methods all require special vehicles or personnel to be on-site for operation, with low detection efficiency and difficulty in meeting the needs of routine road monitoring.

[0004] Generally speaking, due to defects such as destructiveness, high cost, low efficiency and result uncertainty, traditional detection technologies limit their wide application in road maintenance. Therefore, there is an urgent need to develop a non-invasive, low-cost and real-time monitoring method for detecting subgrade cavities. Summary of the Invention

[0005] The present invention provides a method, device and storage medium for detecting subgrade cavities based on vehicle vibration signals to solve the technical problems that the existing detection methods will cause secondary damage to the road surface structure or have too high implementation costs.

[0006] To solve the above technical problems, the present invention provides a method for detecting subgrade cavities based on vehicle vibration signals, including the following steps:

[0007] Step S1: Install at least three acceleration sensors on the vehicle to collect the vibration signals in the vertical and horizontal directions in real time when the vehicle is driving on the road section to be measured;

[0008] Step S2: Analyze the vibration signal, extract the wave velocity and reflection intensity characteristics, and distinguish between a normal roadbed and a roadbed with voids;

[0009] Step S3: For a roadbed with a cavity, a plurality of acceleration sensors are used to receive vibration signals and determine the location of the cavity.

[0010] Preferably, the vibration signals in the vertical and horizontal directions collected in step S1 are preprocessed to remove noise by setting a bandpass filter.

[0011] Preferably, the passband range of the bandpass filter is set to be consistent with the frequency range of the vibration signal caused by the roadbed cavity.

[0012] Preferably, step S2 includes: analyzing the received vibration signal, and when the wave velocity is less than a set threshold and the intensity of the reflected wave peak is greater than the set threshold, it is determined that there is a hollow roadbed.

[0013] Preferably, in step S1, when installing the acceleration sensor, vibration interference sources and electromagnetic interference sources are avoided.

[0014] Preferably, the method for positioning in step S3 includes:

[0015] Step S31: using one of the acceleration sensors as the main sensing point and the other acceleration sensors as auxiliary sensing points to set the coordinates of the roadbed cavity;

[0016] Step S32: Calculate the distance from the main observation point to the roadbed cavity, the distance from the auxiliary observation point to the roadbed cavity, and calculate the distance difference between the two;

[0017] Step S33: determining the two-dimensional plane coordinates of the roadbed cavity by using a time difference positioning method according to the distance difference;

[0018] Step S34: Solving the distance difference and the two-dimensional plane coordinate simultaneous matrix equation to obtain the three-dimensional position coordinates of the roadbed cavity.

[0019] Preferably, in step S2, when distinguishing between a normal roadbed and a roadbed with cavities, historical vibration signal data is matched by a machine learning algorithm to optimize the determination result.

[0020] Preferably, based on the hole position obtained in step S3, the hole position is bound to the real-time position information through GPS positioning and output to a visual map.

[0021] The present invention also provides an electronic device, comprising: a memory, a processor and a computer program, wherein the computer program is stored in the memory and is configured to be executed by the processor to implement the above method.

[0022] The present invention also provides a computer-readable storage medium, characterized in that: a computer program is stored in the computer-readable storage medium, and the computer program is executed by a processor to implement the above method.

[0023] The beneficial effects of the present invention at least include:

[0024] 1) The method based on vehicle vibration signals does not require special vehicles and equipment for detection. It only needs to install sensors on existing vehicles, which greatly reduces the detection cost;

[0025] 2) Data can be collected during the daily operation of the vehicle without additional detection trips, thus realizing continuous monitoring of the subgrade state and improving the detection efficiency;

[0026] 3) The present invention is not only applicable to the detection of subgrade cavities of various types of roads such as highways and urban roads, but also can be applied to the monitoring of other transportation infrastructures such as railways and bridges, and has wide applicability. Description of the Drawings

[0027] Figure 1 It is a schematic flowchart of the method of the embodiment of the present invention;

[0028] Figure 2 It is a schematic installation diagram of vibration signal acquisition of the embodiment of the present invention;

[0029] Figure 3 It is a schematic diagram of the wave transmission principle of the embodiment of the present invention;

[0030] Figure 4 It is a schematic diagram of the positioning principle by time difference of the embodiment of the present invention;

[0031] Figure 5 It is a schematic diagram of the positioning principle by example difference of the embodiment of the present invention. Detailed Embodiments

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0033] Embodiment 1

[0034] As Figure 1 shown, the embodiment of the present invention provides a method for detecting subgrade cavities based on vehicle vibration signals, including the following steps:

[0035] Step S1: Install at least three acceleration sensors on the vehicle to collect the vibration signals in the vertical and horizontal directions in real time when the vehicle is driving on the road section to be measured.

[0036] Specifically, install multiple acceleration sensors on the vehicle chassis to collect the vibration signals generated during the vehicle's driving. The installation positions of the acceleration sensors can be reasonably arranged according to the road surface conditions, the bottom conditions of the vehicle, etc., to ensure that the vibration responses when the vehicle contacts the road surface can be effectively captured.

[0037] In the embodiment of the present invention, since the original vibration signal data collected may be interfered by noise, preprocessing is required. Unnecessary high-frequency noise is removed through a filtering algorithm, and the effective signals related to the roadbed cavities are retained. At the same time, the signals are normalized to ensure that the signal characteristics under different sampling environments can be effectively compared.

[0038] In addition, since the vehicle will be interfered by non-cavity sound waves during driving, a filter needs to be adopted to remove the clutter to retain the vibration signals related to the roadbed cavities. In the acceleration sensor, a band-pass filter can be used to extract the required vibration frequency components. Band-pass filtering is a signal processing technology that allows signals within a specific frequency range to pass through while suppressing signals below and above this frequency range. A band-pass filter is usually composed of a high-pass filter and a low-pass filter. By adjusting the cut-off frequencies of these two filters, the passband range of the band-pass filter can be set. In digital signal processing, a band-pass filter can be implemented through programming, such as using algorithms like FIR filters or IIR filters.

[0039] Step S2: Analyze the vibration signals, extract the wave velocity and reflection intensity characteristics, and distinguish between normal roadbeds and roadbeds with cavities.

[0040] This embodiment first explains the transmission and reflection principle of waves, as Figure 3 shown.

[0041] Transmission and reflection principle: When a wave propagates from one medium to another medium, if it encounters the interface of the medium, a part of the wave will be reflected back along the path opposite to the incident wave but in the same direction. The characteristics of the reflected wave, such as intensity, direction, and phase, depend on the characteristics of the incident wave, such as frequency, wavelength, amplitude, etc., and the properties of the two media, such as density, refractive index, etc. Another part of the wave will pass through the interface and enter another medium and continue to propagate. The characteristics of the transmitted wave, such as intensity, velocity, and direction, also depend on the incident wave and the properties of the two media.

[0042] According to the principles of wave transmission, reflection, and refraction, analyze the propagation characteristics of the vibration signals. There are differences in the waveform characteristics between the vibration signals of the normal roadbed and the roadbed with cavities, especially in terms of the wave transmission speed and reflection intensity.

[0043] Specifically: The vibration wave under a normal roadbed has a relatively fast propagation speed and less signal reflection due to the uniform material. The vibration wave under a cavity area has a slower wave transmission speed due to the discontinuous material and will exhibit obvious reflected wave peaks.

[0044] In the embodiments of the present invention, in order to improve the accuracy of judgment, machine learning algorithms or pattern recognition technologies can also be introduced to train a large amount of historical data for automatically identifying cavity signals.

[0045] Step S3: For a roadbed with cavities, receive vibration signals through multiple acceleration sensors to determine the cavity positions.

[0046] Specifically, the following embodiments are provided in this embodiment for calculating the cavity positions.

[0047] By comparing the vibration signals collected by acceleration sensors at different positions, time difference analysis is performed. When a vehicle passes through the same section of the roadbed, differential calculation is carried out using the arrival times of vibration waves of multiple sensors, so as to accurately locate the cavity positions. Specifically, due to the different installation positions of the sensors, there is a time difference between the signals received by different sensors. Select the moment when a reference sensor receives the signal as the reference, and subtract this reference from the moments when other sensors receive the signals to obtain the arrival time differences of the positioning signals. According to the time differences between the cavity and the reference sensor and other sensors, a hyperbolic equation is established to obtain the position estimate of the unknown point.

[0048] Taking the positioning by a triangular array composed of three sensors as an example, as Figure 4 shown, A, B, and C are the arranged sensors; t1, t2, and t3 are the arrival time differences of the vibration signals respectively; Q is the unknown point, that is, the cavity position; l is the angular reference line; R1, R2, and R3 are the distances from the unknown point to the three reference points respectively; L1, L2, and L3 are the distances between the three reference points respectively. According to the geometric relationship therein, the following equations can be obtained:

[0049]

[0050] By solving the equations, the two-dimensional coordinate positions of the cavities can be determined.

[0051] By comparing the vibration signals collected by acceleration sensors at different positions, time difference analysis is performed. Using the difference in the arrival times of vibration signals in the normal roadbed and cavity areas when a vehicle passes through the same section of the roadbed, the possible cavity areas are determined. Differential calculation can be carried out using the arrival times of vibration waves of multiple sensors, so as to accurately locate the cavity positions.

[0052] After that, through as Figure 5Perform three-dimensional positioning using the method shown. Specifically, take the acceleration sensor arranged at point A as the main observation point, other points as auxiliary observation points, and point Q as the cavity. Among them, r1 is the distance from the main observation point to the emission source, and r i is the distance from the i-th auxiliary observation point to the emission source, all of which are unknowns. Let the coordinates of the main observation point be [x1 y1 z1] T , and the coordinates of the auxiliary observation points [x i y i z i T are all known, and the required emission source position is denoted as [x y z] T .

[0053] Then:

[0054]

[0055] Let S i = [x1 y1 z1] T , and denote u = [x y z] T . According to the geometric relationship, there is:

[0056] (r1 + △r i1 ) 2 = r i 2 (3)

[0057] Substitute equations (1) and (2) into equation (3), where △r i1 = r i - r1, to obtain:

[0058] x1 2 + y1 2 + z1 2 - 2xx1 - 2yy1 - 2zz1 + 2r1Δr i1 + Δr i1 2 = x i 2 + y i 2 + z i 2 - 2xx i - 2yy i - 2zz i ;

[0059] After rearrangement:

[0060] S i T S i - S1 T S1 - 2r1Δr i1 - Δr​i1 2 = 2(S i - S1) T u△r i1 -△r i1 2 = 2(S i - S1) T u;

[0061] Simultaneously solve the matrix equations:

[0062]

[0063] Au = Cr1 + D;

[0064] Find the solution a of Au = C i and the solution b of Au = D i and the solution of r1 and the final solution is γ = a i r1 + b i , that is The value of r1 can also be obtained.

[0065] For the positioning result, this embodiment also provides a visualization method to present the detection result in a graphical manner, obtain the real-time position information of the vehicle through the GPS module, and locate the area where there may be voids on the map. The user can view the results of the subgrade detection in real time, including information such as the specific location of the void, the size of the void, and the reliability of the detection. If major safety hazards are found, an alarm signal can also be sent to remind the relevant maintenance department to take measures.

[0066] Embodiment 2

[0067] This embodiment provides a method for installing an acceleration sensor. As shown in (b) of Figure 2 , by installing a trailer at the rear of the vehicle, the following beneficial effects can be achieved by installing through the trailer.

[0068] 1) Use the trailer as a physical carrier to fix at least three acceleration sensors to ensure stable sensor positions and reasonable distributions, such as arranged in a triangular array, to capture multi-dimensional vibration signals during vehicle driving. At the same time, the applicability design is extensive. Through the trailer, different vehicle models can be adapted without modifying the original vehicle structure, improving the universality of the solution, facilitating the rapid installation and disassembly of sensors, large-scale deployment, and regular monitoring, suitable for detection requirements in different scenarios, avoiding the use of high-cost special detection vehicles, and realizing "vehicle-mounted detection" using the existing traffic flow, greatly reducing the deployment cost.

[0069] 2) The trailer is detachably installed from the main vehicle, which can reduce mechanical coupling interference, improve the signal-to-noise ratio (SNR) of vibration signals, and provide cleaner raw data for feature extraction. The trailer can also be designed with shock-absorbing devices such as springs or rubber pads to further isolate clutter other than random road vibrations.

[0070] 3) The trailer allows the sensors to be close to the road surface, such as at the chassis position, enhancing the sensitivity to roadbed vibration responses. At the same time, the sensor array layout on the trailer supports the time difference positioning algorithm, providing the necessary data for subsequent cavity position calculation and reducing single-point errors.

[0071] Since the trailer is an independent operating unit, through the trailer installation method of this embodiment, without modifying the vehicle, the following improvements can be made: integrating an analog band-pass filter or an anti-aliasing filter inside the vehicle to perform preliminary filtering on the raw signal and reduce the complexity of subsequent signal processing; the trailer can be equipped with a wireless transmission module such as 5G or LoRa to transmit vibration signals to the cloud or local processing unit in real time, and at the same time, edge computing capabilities can be introduced to reduce data processing latency; an automatic calibration mechanism for the trailer, such as GPS-based positioning compensation or sensor zero calibration, to reduce errors caused by installation position deviation or environmental changes; enhancing the waterproof, dustproof, and corrosion-resistant functions of the trailer to ensure that the sensors can still work stably in humid, dusty, and extreme temperature environments.

[0072] Specifically, in this embodiment, the sensors and the trailer are installed in a non-integrated manner. The sensors are fixed on the mounting surface by means of bolt connection, magnetic base connection, adhesive T-bolt connection, etc., and interference signals are filtered through a filter. During installation, it is also necessary to ensure that there is no interference from substances such as vibrations, electromagnetic interference, and corrosive liquids at the installation position that may have a significant impact on the accuracy of the sensors.

[0073] The present invention also provides an electronic device, including: a memory, a processor, and a computer program. The computer program is stored in the memory and is configured to be executed by the processor to implement the above method.

[0074] The present invention also provides a computer-readable storage medium, characterized in that: a computer program is stored in the computer-readable storage medium, and the computer program is executed by the processor to implement the above method.

[0075] A method for detecting roadbed cavities based on vehicle vibration signals provided by the present invention is an efficient road detection technology. First, this method can collect and analyze vibration signals in real time when a vehicle passes by, without the need for additional detection equipment or manual intervention, thus achieving real-time monitoring of roadbed cavities. Secondly, compared with traditional detection methods, such as ground-penetrating radar, geological perspective instruments, etc., the method based on vehicle vibration signals does not require road-breaking construction, reducing the detection cost. In addition, by analyzing the changes in vibration signals when a vehicle passes by, the location and size of roadbed cavities can be accurately identified, improving the detection sensitivity. Finally, this method does not require complex equipment and professional knowledge, and only needs to install sensors on existing roads, which is easy to implement and promote.

[0076] Through the present invention, road safety can be improved, and roadbed cavities can be discovered and repaired in a timely manner. The service life of the road can be extended. By regularly detecting roadbed cavities and repairing them in a timely manner, the damage speed of the road can be delayed, and the service life of the road can be extended. The road maintenance plan can be optimized. The detection method based on vehicle vibration signals can provide accurate information about roadbed cavities, helping the road management department formulate targeted maintenance plans and improve maintenance efficiency. The maintenance cost can be reduced. Since it can monitor and warn of roadbed cavities in real time, the road management department can discover and handle potential problems in a timely manner, avoiding greater maintenance costs caused by the deterioration of problems.

[0077] In summary, the method for detecting roadbed cavities based on vehicle vibration signals has the advantages of real-time monitoring, low cost, high sensitivity, easy implementation, etc., and can significantly improve road safety, extend the service life of the road, optimize the road maintenance plan, reduce the maintenance cost, and promote technological progress. Therefore, this method has broad application prospects in the field of road detection and maintenance.

[0078] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. Only the preferred embodiments of the present invention are expressed. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the present invention. As long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0079] It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. A subgrade cavity detection method based on vehicle vibration signals, characterized in that: The following steps are involved: Step S1: installing at least three acceleration sensors on the vehicle to collect vertical and horizontal vibration signals of the vehicle in real time when the vehicle is traveling on the road section to be tested; Step S2: Analyze the vibration signal, extract the wave velocity and reflection intensity characteristics, and distinguish between a normal roadbed and a roadbed with voids; Step S3: For a roadbed with a cavity, a plurality of acceleration sensors are used to receive vibration signals and determine the location of the cavity.

2. The method for detecting roadbed cavities based on vehicle vibration signals according to claim 1, wherein: The vibration signals in the vertical and horizontal directions collected in step S1 are preprocessed to remove noise by setting a bandpass filter.

3. The subgrade cavity detection method based on vehicle vibration signals according to claim 2, wherein: The passband range of the bandpass filter is set to be consistent with the frequency range of the vibration signal caused by the roadbed cavity.

4. A method for detecting roadbed cavities based on vehicle vibration signals according to claim 1, characterized in that: Step S2 includes: analyzing the received vibration signal, and when the wave velocity is less than a set threshold and the intensity of the reflected wave peak is greater than the set threshold, it is determined that there is a hollow roadbed.

5. A subgrade cavity detection method based on vehicle vibration signals according to claim 1, characterized in that: Step S1: When installing the acceleration sensor, avoid vibration interference sources and electromagnetic interference sources.

6. The method for detecting subgrade cavities based on vehicle vibration signals according to claim 1, characterized in that: The method for positioning in step S3 includes: Step S31: using one of the acceleration sensors as the main sensing point and the other acceleration sensors as auxiliary sensing points to set the coordinates of the roadbed cavity; Step S32: Calculate the distance from the main observation point to the roadbed cavity, the distance from the auxiliary observation point to the roadbed cavity, and calculate the distance difference between the two; Step S33: determining the two-dimensional plane coordinates of the roadbed cavity by using a time difference positioning method according to the distance difference; Step S34: Solving the distance difference and the two-dimensional plane coordinate simultaneous matrix equation to obtain the three-dimensional position coordinates of the roadbed cavity.

7. A method for detecting roadbed cavities based on vehicle vibration signals according to claim 1, characterized in that: In step S2, when distinguishing between a normal roadbed and a roadbed with cavities, the historical vibration signal data is matched through a machine learning algorithm to optimize the determination result.

8. A method for detecting roadbed cavities based on vehicle vibration signals according to claim 1, characterized in that: Based on the hole position obtained in step S3, the hole position is bound to the real-time position information through GPS positioning and output to the visual map.

9. An electronic device, comprising: A memory, a processor and a computer program, characterized in that the computer program is stored in the memory and is configured to be executed by the processor to implement the method according to any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and the computer program is executed by a processor to implement the method according to any one of claims 1 to 8.

Images