Vehicle speed detection method and system based on pavement response and storage medium

Abstract

The invention provides a vehicle speed detection method and system based on road surface response and a storage medium, and belongs to the technical field of road engineering.The method comprises the following steps that at least one strain sensor is buried in an asphalt layer of a road surface, and under the effect of vehicle loads, strain response waveforms of the strain sensors are collected; based on the strain response waveform, standard strain slopes corresponding to two adjacent strain data points are calculated, a curve of the standard strain slopes and detection time is drawn, a standard strain slope waveform is established, and loading time corresponding to the standard strain slope waveform is calculated; and collecting the temperature of the pavement asphalt layer, and calculating the moving speed of the vehicle according to the loading time and the temperature of the pavement asphalt layer. The detection method is not influenced by the detection distance and severe weather, the vehicle speed can be determined only through the detection result of at least one strain sensor, cooperative work of results of multiple strain sensors is not needed, and the detection stability and reliability are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of road engineering, and in particular relates to a vehicle speed detection method, system and storage medium based on road surface response. Background Art

[0002] Road vehicle speed detection is an important means of monitoring and controlling traffic flow, especially in bad weather such as rain, snow, and fog, it is necessary to monitor the road speed in real time to avoid traffic accidents caused by speeding. Speed ​​detection can also reflect the real-time congestion of the road in real time, which is conducive to the traffic management department to find the low speed position (congestion position) in time, so as to divert traffic and improve the traffic operation efficiency of the road.

[0003] The current vehicle speed detection methods mainly include two types: roadside vehicle speedometer detection method and road surface internal ground sensing coil detection method. The detection distance and applicable weather conditions of the roadside vehicle speedometer detection method are limited. At long distances or in bad weather, the ultrasonic and other signals received by the speedometer are severely attenuated, resulting in a significant decrease in detection accuracy. At the same time, for multi-lane roads, due to the obstruction of vehicles in the outer lanes, the vehicle speedometer is also difficult to detect the speed of vehicles in the middle lane, which has great limitations. The road surface internal ground sensing coil detection method calculates the moving speed of the vehicle based on the time difference between the vehicle passing through at least two ground sensing coils continuously. Therefore, the ground sensing coil detection method requires the burial of multiple sets of coil strain sensors, relying on the detection results of multiple coils to collaboratively determine the speed of the vehicle. If one of the coils fails, the entire detection system cannot work. This feature significantly affects the detection stability of the ground sensing coil detection method, resulting in insufficient reliability of the road surface internal ground sensing coil detection method. Summary of the invention

[0004] In order to overcome the above-mentioned shortcomings of the prior art, the present invention provides a vehicle speed detection method based on road surface response, comprising the following steps: At least one strain sensor is buried inside the asphalt layer of the road surface, and under the action of vehicle load, a strain response waveform of the strain sensor is collected; Based on the strain response waveform, the standardized strain slope corresponding to two adjacent strain data points is calculated, a curve of the standardized strain slope and the detection time is drawn, a standardized strain slope waveform is established, and the loading time corresponding to the standardized strain slope waveform is calculated; The temperature of the asphalt layer of the road surface is collected, and the moving speed of the vehicle is calculated according to the loading time and the temperature of the asphalt layer of the road surface.

[0005] Preferably, the calculation of the normalized strain slope corresponding to two adjacent strain data points is performed by the following formula: ; in, Dis the normalized strain slope, yes j +1 time point strain response data, yes j Strain response data at time points, is the time difference between two points in time. is the maximum strain value of the strain response waveform, abs is the absolute value function.

[0006] Preferably, the calculation of the loading time corresponding to the standardized strain slope waveform comprises the following steps: Taking 1 as the threshold, determine the starting point in the standardized strain slope waveform, and take the valley point in the middle of the standardized strain slope waveform as the halfway point; The half-wave waveform time between the starting point and the half-wave point was calculated, and twice the half-wave waveform time was taken as the loading time of the strain slope waveform.

[0007] Preferably, the moving speed of the vehicle is calculated by the following formula: ; in, V is the vehicle moving speed, in km / h; n is the number of strain sensors used, n ≥1; i Number the strain sensor; t i According to i The loading time determined by the strain response waveform of each strain sensor, in seconds; T i is the temperature of the asphalt layer of the road surface, in °C.

[0008] Preferably, the embedding direction of the strain sensor is perpendicular to the driving direction or parallel to the driving direction.

[0009] Preferably, the plane position where the strain sensor is buried is 1.0m-1.2m away from the center line of the lane, and the buried depth of the strain sensor is not less than 4cm and does not exceed the bottom of the asphalt layer.

[0010] Preferably, the distance between two adjacent strain sensors is greater than 50 cm.

[0011] The present invention also provides a vehicle speed detection system based on road surface response, comprising: A data acquisition module is used to bury at least one strain sensor inside the asphalt layer of the road surface, and collect the strain response waveform of the strain sensor under the action of vehicle load; A loading time acquisition module is used to calculate the normalized strain slope corresponding to two adjacent strain data points based on the strain response waveform, draw a curve of the normalized strain slope and the detection time, establish a normalized strain slope waveform, and calculate the loading time corresponding to the normalized strain slope waveform; The speed calculation module is used to collect the temperature of the asphalt layer of the road surface and calculate the moving speed of the vehicle according to the loading time and the temperature of the asphalt layer of the road surface.

[0012] The present invention also provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and the computer program is suitable for being loaded by a processor to execute the vehicle speed detection method.

[0013] The vehicle speed detection method provided by the present invention has the following beneficial effects: The present invention can calculate the normalized strain slope corresponding to two adjacent strain data points by burying at least one strain sensor inside the asphalt layer of the road surface and collecting the strain response waveform of the strain sensor; can establish a normalized strain slope waveform by drawing a curve of the normalized strain slope and the detection time, and the process is not affected by the detection distance and bad weather; can calculate the loading time corresponding to the normalized strain slope waveform through the normalized strain slope waveform, and can accurately calculate the speed of the vehicle through the loading time and the collected temperature data of the asphalt layer of the road surface. In addition, the solution of the present invention can determine the vehicle speed through the detection result of at least one strain sensor, without the need for the coordinated work of the results of multiple strain sensors, thereby improving the stability and reliability of the detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiment of the present invention and its design scheme, the following briefly introduces the drawings required for this embodiment. The drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0015] Figure 1 is a flow chart of the method of the present invention; Figure 2 A schematic diagram of the embedding direction of the strain sensor of the present invention; Figure 3 It is a schematic diagram of the plane embedding position of the strain sensor of the present invention; Figure 4 It is a schematic diagram of the vertical buried position of the strain sensor of the present invention; Figure 5 It is a schematic diagram of calculating the strain response waveform loading time of the present invention; Figure 6 The vertical and planar buried positions of the strain sensors in the embodiment of the present invention are schematic diagrams; wherein: Figure 6 (a) is the vertical position diagram of the strain sensor. Figure 6 (b) is a schematic diagram of the lateral position of the strain sensor.

[0016] Figure 7 This is a schematic diagram of the calculation of the loading time of the strain response waveform under the action of the first vehicle in an embodiment of the present invention; wherein, Figure 7 (a) is the lateral strain response waveform, Figure 7 (b) is the longitudinal strain response waveform.

[0017] Figure 8 This is a schematic diagram of the calculation of the loading time of the strain response waveform under the action of the second vehicle in an embodiment of the present invention; wherein, Figure 8 (a) is the lateral strain response waveform, Figure 8 (b) is the longitudinal strain response waveform. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to better understand the technical solution of the present invention and implement it, the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the scope of protection of the present invention.

[0019] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the technical solutions of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0020] In addition, the terms "first", "second", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance. In the description of the present invention, it should be noted that, unless otherwise clearly specified or limited, the terms "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. In the description of the present invention, unless otherwise specified, "plurality" means two or more, which will not be described in detail here.

[0021] Example The present invention provides a vehicle speed detection method based on road surface response, specifically as follows Figure 1 As shown, the following steps are included: Step 1: at least one strain sensor is buried inside the asphalt layer of the road surface, and the strain response waveform of the strain sensor is collected under the action of vehicle load.

[0022] The strain sensor is buried and compacted when the asphalt layer is paved on the newly built road. For the built road, the asphalt layer can be grooved and then the strain sensor is buried. After burial, the hot mix asphalt mixture is used for backfilling and compaction.

[0023] The buried direction of the strain sensor should be horizontal (perpendicular to the driving direction) or vertical (parallel to the driving direction). For the sake of simplicity, they are called horizontal sensors or vertical sensors, respectively. Figure 2 As shown in the figure, the distance between adjacent lateral sensors and longitudinal sensors is greater than 50 cm; the plane position of the buried strain sensor should be within 1.0m~1.2m from the center line of the lane, such as Figure 3 As shown; the vertical buried depth of the strain sensor is not less than 4cm and does not exceed the bottom of the asphalt layer. The asphalt layer is located above the base layer, and the base layer is located above the soil foundation. Figure 4 shown.

[0024] After the strain sensor is buried, a data recorder is used to collect the strain response waveform of the asphalt layer under the action of a moving vehicle, and the data frequency is not less than 100 Hz.

[0025] Step 2: Based on the strain response waveform, calculate the normalized strain slope corresponding to two adjacent strain data points, draw a curve of normalized strain slope and detection time, establish a normalized strain slope waveform, and calculate the loading time corresponding to the normalized strain slope waveform.

[0026] The normalized strain slope is calculated as follows: ; in, D is the normalized strain slope, yes j +1 time point strain response data, yes j Strain response data at time points, is the time difference between two points in time. is the maximum strain value of the strain response waveform, abs is the absolute value function.

[0027] A curve between the normalized strain slope and the detection time is drawn according to the calculated normalized strain slope, and a normalized strain slope waveform is established.

[0028] Calculating the loading time corresponding to the normalized strain slope waveform includes the following steps: Taking 1 as the threshold, the starting point in the standardized strain slope waveform is determined, and the valley point in the middle of the standardized strain slope waveform is taken as the half-way point.

[0029] Calculate the half-wave waveform time between the starting point and the half-wave point, and take twice the half-wave waveform time as the loading time of the strain slope waveform, such as Figure 5 shown.

[0030] Step 3: Collect the temperature of the asphalt layer of the road surface, and calculate the moving speed of the vehicle according to the loading time and the temperature of the asphalt layer of the road surface. The specific calculation is based on the following formula: ; in, V is the vehicle moving speed, in km / h; n is the number of strain sensors used, n ≥1; i Number the strain sensor; t i According to i The loading time determined by the strain response waveform of each strain sensor, in seconds; T i is the temperature of the asphalt layer of the road surface, in °C.

[0031] The method of the present invention is further described below in conjunction with a specific embodiment and the accompanying drawings.

[0032] In this embodiment, a lane of a certain asphalt pavement is selected for speed detection. During the paving period of the asphalt layer, a strain sensor is buried inside it. In this embodiment, the thickness of the asphalt layer of the asphalt pavement is 30 cm, and the buried depth is selected to be 13 cm. The schematic diagram of the buried position of the strain sensor near the middle of the asphalt layer is as shown in the figure. Figure 6 As shown, Figure 6 (a) is a schematic diagram of the vertical position (along the ground depth direction) of the strain sensor; the plane position of the buried strain sensor is as follows Figure 6 As shown in (b), lateral sensors and longitudinal sensors are buried along the driving direction, 1.1 m away from the center line of the lane. Theoretically, one strain sensor can be buried to complete the detection of vehicle speed, but in order to increase the reliability of detection, strain sensors are buried in the lateral and longitudinal directions respectively in this embodiment, and the spacing between adjacent lateral sensors and longitudinal sensors is 80 cm.

[0033] The DH3820 data acquisition instrument is connected to the strain sensor to collect the strain response waveform of the road surface under the action of vehicle load. The sampling frequency of DH3820 is 100Hz, that is, 100 strain response data points are collected every second. While the strain is being detected, a temperature gun is used to detect the temperature condition of the road surface in real time.

[0034] In this embodiment, the road surface strain response waveforms detected under the action of two vehicles driving are taken as an example to introduce the process of obtaining the vehicle speed. The road surface temperature under the two working conditions is 23°C.

[0035] Under the action of the first vehicle, the strain response waveforms of the lateral and longitudinal sensors collected by the DH3820 data acquisition instrument are as follows: Figure 7 As shown, Figure 7 (a) is the lateral strain response waveform (the strain response waveform collected by the lateral sensor), Figure 7 (b) is a longitudinal strain response waveform (strain response waveform collected by the longitudinal sensor). According to the method provided by the present invention, the collected lateral strain response waveform and longitudinal strain response waveform are converted into standardized strain slope waveforms, and the loading times corresponding to the two types of waveforms are determined, which are 0.52s and 0.60s respectively.

[0036] Based on the determined loading time, the vehicle moving speed is calculated using the formula provided by the present invention, and the calculation process is as follows: ; Therefore, the vehicle speed corresponding to the strain response waveform is 12.62 km / h, and the speed detection of the first vehicle is completed.

[0037] Under the action of the second vehicle, the strain response waveforms of the lateral and longitudinal sensors collected by the DH3820 data acquisition instrument are as follows: Figure 8 As shown, Figure 8 (a) is the lateral strain response waveform, Figure 8 (b) is the longitudinal strain response waveform. Similarly, the collected transverse strain response waveform and longitudinal strain response waveform are converted into standardized strain slope waveforms, and the loading times corresponding to the two types of waveforms are determined to be 0.38s and 0.36s, respectively.

[0038] Based on the determined loading time, the vehicle moving speed is calculated using the formula, and the calculation process is as follows: ; Therefore, the vehicle speed corresponding to the strain response waveform is 19.02 km / h, and the speed detection of the second vehicle is completed.

[0039] In summary, by using the vehicle speed detection method based on road surface response proposed by the present invention, the vehicle speed can be determined by the strain response waveform of the strain sensor inside the road surface. This method is flexible in lane detection and can effectively solve the drawbacks of the roadside vehicle speed meter detection method being interfered by bad weather and multiple lanes; at the same time, the method of the present invention can determine the vehicle speed by relying on the detection results of a single strain sensor, which effectively solves the problem of poor coordination stability of multiple groups of coils in the road surface internal ground sensing coil detection method. Of course, multiple strain sensors can also be used in the present invention to work together, which can further increase the reliability and stability of the detection.

[0040] The present invention also provides a vehicle speed detection system based on road surface response, comprising: A data acquisition module is used to bury at least one strain sensor inside the asphalt layer of the road surface, and collect the strain response waveform of the strain sensor under the action of vehicle load; A loading time acquisition module is used to calculate the normalized strain slope corresponding to two adjacent strain data points based on the strain response waveform, draw a curve of the normalized strain slope and the detection time, establish a normalized strain slope waveform, and calculate the loading time corresponding to the normalized strain slope waveform; The speed calculation module is used to collect the temperature of the asphalt layer of the road surface and calculate the moving speed of the vehicle according to the loading time and the temperature of the asphalt layer of the road surface.

[0041] The present invention also provides a computer-readable storage medium, which stores a computer program. The computer program is suitable for being loaded by a processor to execute the vehicle speed detection method.

[0042] The above embodiments are only preferred specific implementation methods of the present invention, and the protection scope of the present invention is not limited thereto. Any simple changes or equivalent replacements of the technical solutions that can be obviously obtained by any technician familiar with the field within the technical scope disclosed in the present invention belong to the protection scope of the present invention.

Claims

1. A vehicle speed detection method based on road surface response, characterized in that: The steps include: At least one strain sensor is buried inside the asphalt layer of the road surface, and under the action of vehicle load, a strain response waveform of the strain sensor is collected; Based on the strain response waveform, the standardized strain slope corresponding to two adjacent strain data points is calculated, a curve of the standardized strain slope and the detection time is drawn, a standardized strain slope waveform is established, and the loading time corresponding to the standardized strain slope waveform is calculated; The temperature of the asphalt layer of the road surface is collected, and the moving speed of the vehicle is calculated according to the loading time and the temperature of the asphalt layer of the road surface.

2. The vehicle speed detection method according to claim 1, characterized in that: The calculation of the normalized strain slope corresponding to two adjacent strain data points is performed by the following formula: ； in, D is the normalized strain slope, yes j +1 time point strain response data, yes j Strain response data at time points, is the time difference between two points in time. is the maximum strain value of the strain response waveform, abs is the absolute value function.

3. The vehicle speed detection method according to claim 1, characterized in that: The method of calculating the loading time corresponding to the normalized strain slope waveform comprises the following steps: Taking 1 as the threshold, determine the starting point in the standardized strain slope waveform, and take the valley point in the middle of the standardized strain slope waveform as the halfway point; The half-wave waveform time between the starting point and the half-wave point was calculated, and twice the half-wave waveform time was taken as the loading time of the strain slope waveform.

4. The vehicle speed detection method according to claim 1, characterized in that: The moving speed of the vehicle is calculated by the following formula: ； in, V is the vehicle moving speed, in km / h; n is the number of strain sensors used, n ≥1; i Number the strain sensor; t i According to i The loading time determined by the strain response waveform of each strain sensor, in seconds; T i is the temperature of the asphalt layer of the road surface, in °C.

5. The vehicle speed detection method according to claim 1, characterized in that: The embedding direction of the strain sensor is perpendicular to the driving direction or parallel to the driving direction.

6. The vehicle speed detection method according to claim 1, characterized in that: The plane position where the strain sensor is buried is 1.0m-1.2m away from the center line of the lane, and the buried depth of the strain sensor is not less than 4cm and does not exceed the bottom of the asphalt layer.

7. The vehicle speed detection method according to claim 1, characterized in that: The distance between two adjacent strain sensors is greater than 50 cm.

8. A vehicle speed detection system based on road surface response, characterized in that: include: A data acquisition module is used to bury at least one strain sensor inside the asphalt layer of the road surface, and collect the strain response waveform of the strain sensor under the action of vehicle load; A loading time acquisition module is used to calculate the normalized strain slope corresponding to two adjacent strain data points based on the strain response waveform, draw a curve of the normalized strain slope and the detection time, establish a normalized strain slope waveform, and calculate the loading time corresponding to the normalized strain slope waveform; The speed calculation module is used to collect the temperature of the asphalt layer of the road surface and calculate the moving speed of the vehicle according to the loading time and the temperature of the asphalt layer of the road surface.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and the computer program is suitable for being loaded by a processor to execute the vehicle speed detection method according to any one of claims 1 to 7.

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