A system and method for synchronously measuring vehicle axle load spectrum and road surface response

Abstract

The present invention discloses a system and method for synchronously measuring a vehicle axle load spectrum and road surface response, comprising: a detection module including sensing units located at the entrance and exit of a detection area, and an axle load measurement unit and a response measurement unit located within the detection area; a data acquisition module for collecting axle load measurement signals, response measurement signals, and high and low level signals of the sensing units, and storing them in a dynamic array; a data analysis module configured to extract the measurement signals of each unit from the dynamic array, and obtain the changes in the axle load and driving trajectory of a certain vehicle model in response to the road surface based on the data of each unit. The system realizes the collection of the vehicle speed, vehicle model, axle load, and vehicle driving trajectory, obtains the position of the tire acting on the road surface through the vehicle driving trajectory, and combines the road surface response data to more deeply analyze the influence of axle load and driving trajectory on road surface response, providing effective data for road surface damage mechanism analysis.

Description

Technical Field

[0001] The present invention relates to the technical field of road design, and in particular to a system and method for synchronously measuring a vehicle axle load spectrum and a road surface response. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Vehicle axle load is a crucial factor in road design. Rapid and accurate axle load measurement is a crucial basis for pavement structure design and traffic load analysis. Furthermore, pavement response, which reflects the road's response to varying vehicle axle loads, serves as primary reference data for studying pavement damage mechanisms. The combination of vehicle axle load spectra and pavement response data can further reveal the relationship between vehicle axle load and pavement response, playing a crucial role in road design, construction, and management.

[0004] At present, the main problems in the measurement of vehicle axle load spectrum and road surface response are as follows:

[0005] 1) Existing equipment for measuring vehicle axle load spectra and road surface response is separate and designed by different manufacturers. Field testers need to purchase both sets of equipment to obtain axle load spectrum data for the current road and its impact on road surface response. During data collection, the two devices operate independently, measuring axle load spectrum data and road surface response data respectively. This discrepancy in sampling frequency and data storage formats makes fusion analysis of the two data difficult, hindering the extraction of useful information from both sets and hindering the in-depth exploration and application of axle load spectrum and road surface response data.

[0006] 2) For pavement response measurements, the sensor output is related to the vehicle's trajectory within the lane. However, current pavement response testing equipment generally does not consider the impact of vehicle trajectory and is not equipped with corresponding sensors. Therefore, the integrity of the tested pavement response data needs to be further improved.

[0007] 3) When simultaneously collecting vehicle axle load spectra and road surface response, due to the large number of installed sensors and the long lane length covered by the detection area, the following difficult-to-solve problems are inevitable during the actual detection process: the previous vehicle has not yet left the detection area, but the next vehicle has entered the detection area. Multiple vehicles are detected at the same time, which makes data testing and analysis difficult, and it is impossible to perform individual testing and analysis of the axle load spectrum and road surface response of each vehicle. Summary of the Invention

[0008] To address the above-mentioned issues, the present invention proposes a system and method for synchronously measuring vehicle axle load spectrum and road surface response, which enables the collection of vehicle speed, vehicle type, axle load, and vehicle driving trajectory. The position of the tire acting on the road surface is obtained through the vehicle driving trajectory. Combined with the road surface response data, a more in-depth analysis of the impact of axle load and driving trajectory on road surface response can be conducted, providing effective data for the analysis of road surface damage mechanisms.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a system for synchronously measuring vehicle axle load spectrum and road surface response, comprising:

[0011] The detection module includes sensing units located at the entrance and exit of the detection area, and an axle load measurement unit and a response measurement unit located within the detection area; the axle load measurement unit includes a first sensor and a second sensor disposed in parallel, and a third sensor disposed between the two sensors and inclined at a certain angle;

[0012] The data acquisition module is used to collect the axle load measurement signal, the response measurement signal and the high and low level signals of the sensing unit and store them in a dynamic array;

[0013] The data analysis module is configured to extract the measurement signal of each unit from the dynamic array and obtain the changes in the axle load and driving trajectory of a certain vehicle model in response to the road surface based on the data of each unit; it includes:

[0014] Distinguish adjacent vehicles based on the high and low level signals at the entrance, and determine the axle load measurement signal and response measurement signal of each vehicle based on the high and low level signals at the entrance and exit;

[0015] The vehicle speed is obtained based on the time it takes for the vehicle to pass the first sensor and the second sensor, the wheelbase is obtained based on the vehicle speed and the time difference between adjacent axles of the vehicle passing the same sensor, and the vehicle model is determined based on the wheelbase;

[0016] Obtaining the vehicle axle load according to the vehicle speed and the axle load measurement signals measured when the vehicle passes the first sensor and the second sensor respectively;

[0017] Determine the driving trajectory based on the installation angle of the third sensor, the parallel distance between the first sensor and the second sensor, the time it takes to pass the second sensor and the third sensor, and the vehicle speed;

[0018] The position where the vehicle tire acts on the road surface is determined according to the driving trajectory, and the road surface response distribution is obtained according to the response measurement signal at the corresponding position.

[0019] As an optional implementation, the induction unit includes a ground sensing coil and a ground sensing coil processing circuit. When a vehicle passes by the ground sensing coil, the output frequency of the ground sensing coil processing circuit changes. Specifically, a sinusoidal signal is generated by a resonant circuit, and the sinusoidal signal is converted into a rectangular wave signal. When a vehicle passes by the ground sensing coil, the frequency of the rectangular wave signal changes, and the change in the rectangular wave frequency is converted into a high / low level signal for indicating whether a vehicle passes by the ground sensing coil.

[0020] As an optional implementation, the axle load measurement unit amplifies the output signals of the three sensors and converts them into voltage signals for collection by the data collection module;

[0021] In the response measurement unit, a resistance signal that changes as the road surface strain changes is output, the resistance signal is converted into a voltage signal using a Wheatstone bridge, and the voltage signal is amplified by a differential operational amplifier circuit and then collected.

[0022] As an optional implementation, the data acquisition module and the data analysis module are operated synchronously; wherein, the data acquisition module continuously samples each unit data at a set sampling frequency and stores it in a dynamic array, and the data analysis module simultaneously extracts each unit data from the dynamic array and analyzes the data.

[0023] As an optional implementation, when the upper capacity limit of the dynamic array is reached, the storage is continued to be overwritten from the starting position of the dynamic array.

[0024] As an optional implementation, the time difference is obtained based on the time when each axle passes the first sensor and the second sensor, and the vehicle speed under each axle is obtained based on the time difference and the parallel distance between the first sensor and the second sensor. The vehicle speed is obtained by averaging the various speeds.

[0025] As an optional implementation manner, the wheelbase is obtained according to the product of the vehicle speed and the time difference between adjacent axles of the vehicle passing the same sensor.

[0026] As an optional embodiment, the sum of all axle load measurement signals measured when one axle of the vehicle passes through the second sensor is calculated, and the sums of all axles are added together to obtain the axle load measurement signal of the second sensor;

[0027] Calculating the sum of all axle load measurement signals measured when one axle of the vehicle passes through the first sensor, and adding the sums of all axles to obtain the axle load measurement signal of the first sensor;

[0028] The axle load measurement signal of the second sensor and the axle load measurement signal of the first sensor are averaged to obtain the axle load of the vehicle.

[0029] As an optional implementation, the distance y between the driving trajectory of a single-side axle of the vehicle and the lane line is represented as the driving trajectory of the vehicle. According to the installation angle α between the third sensor and the lane line, the parallel distance D between the first sensor and the second sensor, the time t2 passing the second sensor and the time t1 of the third sensor, and the vehicle speed v, the driving trajectory y is determined as: y = x·tanα, x = DV·(t2-t1).

[0030] In a second aspect, the present invention provides a method for synchronously measuring a vehicle axle load spectrum and a road surface response, comprising:

[0031] Acquire high and low level signals from sensing units located at the entrance and exit of the detection area, an axle load measurement signal from an axle load measurement unit located within the detection area, and a response measurement signal from a response measurement unit; wherein the axle load measurement unit includes a first sensor and a second sensor disposed in parallel, and a third sensor disposed between the two sensors and inclined at a certain angle;

[0032] Determine whether a vehicle enters or leaves the detection area based on the high and low level signals of the sensing unit, distinguish adjacent vehicles based on the high and low level signals at the entrance, and determine the axle load measurement signal and response measurement signal of each vehicle based on the high and low level signals at the entrance and exit;

[0033] The vehicle speed is obtained based on the time it takes for the vehicle to pass the first sensor and the second sensor, the wheelbase is obtained based on the vehicle speed and the time difference between adjacent axles of the vehicle passing the same sensor, and the vehicle model is determined based on the wheelbase;

[0034] Obtaining the vehicle axle load according to the vehicle speed and the axle load measurement signals measured when the vehicle passes the first sensor and the second sensor respectively;

[0035] Determine the driving trajectory based on the installation angle of the third sensor, the parallel distance between the first sensor and the second sensor, the time it takes to pass the second sensor and the third sensor, and the vehicle speed;

[0036] The position where the vehicle tire acts on the road surface is determined according to the driving trajectory, and the road surface response distribution is obtained according to the response measurement signal at the corresponding position.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The present invention proposes a system and method for synchronously measuring vehicle axle load spectrum and road surface response. By comprehensively analyzing the two data types of vehicle axle load and road surface response, it provides effective analytical data for road damage mechanism analysis and offers theoretical guidance for road design, construction, and management. It has broad application prospects and promotion value in the field of transportation.

[0039] The present invention proposes a system and method for synchronously measuring vehicle axle load spectrum and road surface response, which realizes the collection of vehicle speed, vehicle type, axle load and vehicle driving trajectory. The position of the vehicle tire acting on the road surface is obtained through the vehicle driving trajectory data. Combined with the road surface response data, a more in-depth analysis of the impact of vehicle axle load and vehicle driving trajectory on road surface response can be achieved, facilitating a more in-depth analysis of the relationship between vehicle axle load and road surface response, and providing more detailed information for road design, construction and management.

[0040] The present invention distinguishes the test data of adjacent vehicles based on the signals of the ground sensing coils at the entrance and exit of the detection area, effectively eliminating the problem of multiple vehicles entering the detection area at the same time. Even if multiple vehicles enter the detection area at the same time, data from different vehicles can be extracted.

[0041] The present invention proposes to simultaneously perform data collection and storage and data analysis and processing in a dual-threaded manner, thereby avoiding vehicle data loss and improving processing efficiency.

[0042] Advantages of additional aspects of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0044] Figure 1 Schematic diagram of the overall structure of the vehicle axle load spectrum and road surface response synchronous measurement system provided in Example 1 of the present invention;

[0045] Figure 2(a)-Figure 2(d) A diagram showing the ground sensing coil processing circuit, the piezoelectric film sensor processing circuit, and the strain sensor processing circuit provided in Example 1 of the present invention;

[0046] Figure 3 This is a flowchart of data collection, storage, analysis and processing provided in Example 1 of the present invention;

[0047] Figure 4 Schematic diagram of data collection, storage, analysis and processing provided by Example 1 of the present invention;

[0048] Figure 5(a)-Figure 5(c) A schematic diagram illustrating the distinction between adjacent vehicle data provided in Example 1 of the present invention;

[0049] Figure 6 This is a schematic diagram of the arrangement of the piezoelectric film sensor and the strain sensor provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0050] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0051] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0052] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0053] In the absence of conflict, the embodiments of the present invention and the features thereof may be combined with each other.

[0054] Example 1

[0055] This embodiment provides a system for synchronously measuring vehicle axle load spectrum and road surface response, including:

[0056] The detection module includes sensing units located at the entrance and exit of the detection area, and an axle load measurement unit and a response measurement unit located within the detection area; the axle load measurement unit includes a first sensor and a second sensor disposed in parallel, and a third sensor disposed between the two sensors and inclined at a certain angle;

[0057] The data acquisition module is used to collect the axle load measurement signal, the response measurement signal and the high and low level signals of the sensing unit and store them in a dynamic array;

[0058] The data analysis module is configured to extract the measurement signal of each unit from the dynamic array and obtain the changes in the axle load and driving trajectory of a certain vehicle model in response to the road surface based on the data of each unit; it includes:

[0059] Determine whether a vehicle enters or leaves the detection area based on the high and low level signals of the sensing unit, distinguish adjacent vehicles based on the high and low level signals at the entrance, and determine the axle load measurement signal and response measurement signal of each vehicle based on the high and low level signals at the entrance and exit;

[0060] The vehicle speed is obtained based on the time it takes for the vehicle to pass the first sensor and the second sensor, the wheelbase is obtained based on the vehicle speed and the time difference between adjacent axles of the vehicle passing the same sensor, and the vehicle model is determined based on the wheelbase;

[0061] Obtaining the vehicle axle load according to the vehicle speed and the axle load measurement signals measured when the vehicle passes the first sensor and the second sensor respectively;

[0062] Determine the driving trajectory based on the installation angle of the third sensor, the parallel distance between the first sensor and the second sensor, the time it takes to pass the second sensor and the third sensor, and the vehicle speed;

[0063] The position where the vehicle tire acts on the road surface is determined according to the driving trajectory, and the road surface response distribution is obtained according to the response measurement signal at the corresponding position.

[0064] In this embodiment, if Figure 1 As shown, the sensing unit uses a ground sensing coil and a ground sensing coil processing circuit. Ground sensing coils are arranged at the entrance and exit of the detection area to detect whether a vehicle enters or leaves the detection area;

[0065] The first sensor, the second sensor and the third sensor are all piezoelectric film sensors, and the axle load measurement unit is installed near the entrance of the detection area;

[0066] The response measurement unit uses a strain sensor and a strain sensor processing circuit. The strain sensor is installed at different positions and depths on the road surface between the exit of the detection area and the axle load measurement unit.

[0067] In this embodiment, the ground sensing coil is used to identify whether a vehicle enters or leaves the detection area. When a vehicle passes through the ground sensing coil, the output frequency of the ground sensing coil processing circuit changes, and then the frequency change is converted into a high-level signal, that is, a high-level signal is output when the vehicle passes through the ground sensing coil, otherwise a low-level signal is output. In this way, it can be determined whether the vehicle passes through the ground sensing coil. A ground sensing coil is set at the entrance and exit of the detection area respectively to determine whether a vehicle enters or leaves the detection area.

[0068] The ground sensing coil processing circuit is shown in Figure 2(a). A sinusoidal signal is generated by the LC resonant circuit in the ground sensing coil oscillation circuit, and the sinusoidal signal is converted into a rectangular wave signal by a transistor. When a vehicle passes over the ground sensing coil, the frequency of the rectangular wave signal in the oscillation circuit changes. The rectangular wave signal is converted into a TTL level signal by a shaping circuit and sent to the input capture pin of the microcontroller to capture the frequency of the TTL level signal. Since the frequency of the TTL level signal is different when there is no vehicle passing over the ground sensing coil and when there is a vehicle passing over the ground sensing coil, a high / low level signal is sent through another pin according to the frequency of the TTL level signal, which is used to indicate whether the vehicle is above the ground sensing coil.

[0069] In this embodiment, the vehicle axle load, vehicle speed and vehicle type are detected by parallel piezoelectric film sensors, and the vehicle driving trajectory is detected by three piezoelectric film sensors. As shown in Figure 2(b), the piezoelectric film sensor processing circuit is shown. Since the piezoelectric film sensor outputs a weak charge signal, the piezoelectric film sensor processing circuit is required to have a high input impedance. A charge amplifier circuit is designed, and the output signal of the piezoelectric film sensor is amplified and converted into a voltage signal by using the feedback capacitor C1. The feedback resistor R7 is connected in parallel at both ends of the feedback capacitor C1 to improve the stability of the amplifier circuit. The amplification factor of the amplifier circuit is adjusted by the resistors R1, R4, R5 and R6, and the output is a voltage signal with a higher amplitude, thereby realizing the amplification of the output signal for data acquisition.

[0070] In this embodiment, the strain sensor is installed inside the road surface, and in order to obtain response data at different locations and different sections of the road surface, multiple sets of strain sensors are installed at different locations to fully reflect the response characteristics of the road surface; the strain sensor processing circuit is as follows: Figure 2(c)-Figure 2(d) As shown in Figure 2(c), the resistance signal output changes with the change of road strain, that is, the resistance signal output increases with the increase of strain. The Wheatstone bridge in Figure 2(c) is used to convert the resistance signal into a voltage signal. The voltage signal is amplified and collected by the differential operational amplifier circuit in Figure 2(d). In order to improve the signal-to-noise ratio of the signal, RC filtering circuits are used at the input and output of the differential operational amplifier circuit to reduce the influence of high-frequency interference components.

[0071] In this embodiment, after passing through the processing circuit, the above-mentioned sensor signals are all connected to the data acquisition module, and the two-way high / low level signals, three-way axle load measurement signals and multiple-way response measurement signals are collected by using the set sampling frequency, and stored in the dynamic array at the same time; all the above-mentioned data are obtained through the same data acquisition module, with the same sampling frequency and storage format, and in order to ensure the integrity of data collection, a data collection and storage thread is specially set up for real-time collection and storage of each sensor data.

[0072] This embodiment uses an industrial computer with high operating reliability to perform data analysis. A data acquisition module (taking a high-speed data acquisition card as an example) is also installed in the industrial computer, and the collected data is stored in the hard disk of the industrial computer. In order to solve the problem of multiple vehicles entering the detection area at the same time, in addition to the data acquisition and storage threads, a dedicated data analysis and processing thread is also set up to extract and analyze the stored sensor data, separate the vehicle data that is simultaneously in the detection area, and obtain the axle load and road response data of each vehicle.

[0073] Therefore, this embodiment collects and saves the data of each sensor through the data acquisition and storage thread, extracts the stored data through the data analysis and processing thread, and analyzes the data to obtain the vehicle speed, vehicle model, axle load, driving trajectory and road response data. Finally, the analyzed data is sent to the cloud platform through a wireless transmission module connected to the serial port of the industrial computer. Since the device is generally fixed next to the road and power supply is inconvenient, this embodiment uses solar panels and batteries for independent power supply to facilitate the use of the system.

[0074] The wireless data transmission module is connected to the serial port of the industrial computer and is used to send the analyzed vehicle speed, vehicle model, axle load, driving trajectory and road response data to the cloud platform wirelessly. The module has the function of delayed data transmission in the event of network anomalies. When the network is interrupted, the data can be stored in the memory of the wireless data transmission module. When the network returns to normal, the temporarily saved data will be sent to the cloud platform.

[0075] Taking into account the serious degradation of the charging and discharging performance of lithium batteries in low-temperature environments, lead-acid batteries are used as energy sources to power various power modules; solar charging includes photovoltaic panels and a charging management system. The charging management system monitors the status of the lead-acid battery. When the power is reduced, the lead-acid battery is charged at any time through the solar charging system to maintain the battery capacity to meet the usage requirements.

[0076] In this embodiment, if Figure 3 As shown, initialize the dynamic array capacity, sampling frequency, number of sampling channels and range of each channel;

[0077] After initialization, open up data collection and storage threads and data analysis and processing threads;

[0078] The data acquisition and storage thread continuously samples the data of each channel according to the set sampling frequency and stores the collected data in a dynamic array. When a stop acquisition command is received, the data acquisition is stopped;

[0079] The data analysis and processing thread extracts the data of each channel from the dynamic array, analyzes the data, and transmits the analyzed data to the cloud platform through the industrial computer serial port and the wireless data transmission module connected to the serial port. When the stop processing command is received, the data processing is stopped.

[0080] If a single thread is used, two tasks cannot be performed simultaneously. For example, when a single thread is used, data is collected and stored first, and then processed. During the data processing process, if a new vehicle enters the detection area, the vehicle data will be lost because data collection is not performed at this time.

[0081] To this end, this embodiment adopts dual threads. The data acquisition and storage thread is always in the data acquisition stage and puts the collected data into a dynamic array in sequence; the data analysis and processing thread always performs data analysis and processing, extracts data from the dynamic array, and performs corresponding analysis on the data. Through the control of the two threads, a balance is achieved between data acquisition and storage and data analysis and processing.

[0082] When the data storage reaches the upper limit of the dynamic array capacity, the data in front of the dynamic array has been processed, and storage can continue from the starting position of the dynamic array. Therefore, by coordinating the rhythm of data acquisition, storage, and analysis and processing, the dynamic array can be used to achieve temporary storage of data.

[0083] In this embodiment, if Figure 4 As shown in the figure, the data acquisition and storage thread and the data analysis and processing thread share the same dynamic array. When storing, the variable uiSaveCount is used to represent the current stored array number. When the stored array number exceeds the maximum value of the dynamic array, the storage continues to be overwritten from the starting address of the dynamic array. When extracting, the variable uiAnalysisCount is used to represent the current extracted array number. The data before the array number has been processed, and this part of the space can be used to store data again.

[0084] To ensure that all extracted data are valid, data is collected and stored first, and then extracted and analyzed. Since data extraction and analysis are performed in real time, effective data management can achieve synchronization of data collection, storage, and analysis processing. When the stored array number exceeds the capacity of the dynamic array, the data in the previous dynamic array has been analyzed and can be overwritten and stored without losing data.

[0085] In this embodiment, to address the issue of multiple vehicles entering the detection area simultaneously, the vehicle's location is determined based on the high and low level signals at the entrance and exit, and adjacent vehicles are distinguished accordingly. As shown in Figure 5(a), a schematic diagram shows a vehicle just entering the detection area. At this point, the ground sensor coil processing circuit outputs a high level. As the vehicle continues to move forward, it leaves the entrance ground sensor coil, at which point the ground sensor coil processing circuit outputs a low level. As shown in Figure 5(b), when the second vehicle behind it reaches the entrance ground sensor coil, the ground sensor coil output circuit again outputs a high level. Based on the signal characteristics shown in Figure 5(c), adjacent vehicles can be distinguished based on the high and low level signals output by the entrance ground sensor coil. Because the data acquisition and storage threads continuously collect and store data, and the data analysis and processing threads continuously extract, analyze, and process data, and then combine the output signals of the ground sensor coil to distinguish adjacent vehicles, this mechanism effectively extracts data from all vehicles.

[0086] In this embodiment, if Figure 6As shown, three piezoelectric film sensors are installed in the axle load measurement area, of which the first piezoelectric film sensor 1 and the second piezoelectric film sensor 2 are arranged in parallel, and the third piezoelectric film sensor 3 is arranged at an angle; in order to fully reflect the strain at different positions of the road surface, multiple strain sensors 4 are arranged in the response measurement area; the data analysis module distinguishes the axle load measurement signal and response measurement signal of each vehicle according to the high and low level signals, and calculates the vehicle axle load spectrum, vehicle driving trajectory and road response data of the vehicle speed, vehicle model and axle load based on this.

[0087] Specifically:

[0088] The vehicle speed is obtained based on the time it takes for a tire on a certain axle of the vehicle to pass the first piezoelectric film sensor 1 and the second piezoelectric film sensor 2. Assuming that the time it takes for a certain axle on the left side of the vehicle to pass the three piezoelectric film sensors is t1, t2, and t3 respectively, and the distance between the two parallel piezoelectric film sensors is D, the current vehicle speed V is: Thus, a vehicle speed is obtained according to the time taken for each axle to pass through the first piezoelectric film sensor 1 and the second piezoelectric film sensor 2 , and the average of the speeds is used as the vehicle speed.

[0089] The wheelbase is obtained based on the vehicle speed and the time difference between adjacent axles passing the same piezoelectric film sensor, and the vehicle model is determined based on the wheelbase. If the time difference between the 1st and 2nd axles of the vehicle passing the same piezoelectric film sensor is ΔT, then the wheelbase L between the 1st and 2nd axles is axis1 For L axis1 =V·ΔT; similarly, the wheelbases of other axles are obtained, and the vehicle model is determined based on the wheelbase data.

[0090] The vehicle axle load is obtained according to the vehicle speed and the axle load measurement signals measured when the vehicle passes through the first piezoelectric film sensor 1 and the second piezoelectric film sensor 2 respectively; specifically:

[0091] Get the axle load measurement signal x when the vehicle's axle 1 passes the second piezoelectric film sensor 2 2i , the axle measures n signals in total through the second piezoelectric film sensor 2, so the axle load of axle 1 is m axis1 for Among them, C coef is the axle load measurement adjustment factor;

[0092] Similarly, the axle load of each axle of the vehicle when it passes through the second piezoelectric film sensor 2 is obtained, and the axle load data of each axle is accumulated to obtain the axle load data of the current vehicle measured by the second piezoelectric film sensor 2;

[0093] Similarly, similar calculations are performed on the first piezoelectric film sensor 1 to obtain the axle load data measured by the first piezoelectric film sensor 1. Finally, the axle load data tested by the two sensors are averaged and the result is used as the axle load data of the vehicle.

[0094] by Figure 6 The distance y between the driving trajectory of a single axle of the vehicle and the lane line represents the driving trajectory of the vehicle. According to the installation angle α between the third piezoelectric film sensor and the lane line, the parallel distance D between the first piezoelectric film sensor and the second piezoelectric film sensor, the time of passing the second piezoelectric film sensor and the third piezoelectric film sensor, and the vehicle speed, the driving trajectory y is determined as: y=x·tanα, x=D-D1=DV·(t2-t1); finally, the position of the vehicle tire acting on the road surface is determined according to the driving trajectory, and the road surface response data is obtained by statistically analyzing the measurement results of each strain sensor installed at different positions and sections.

[0095] Example 2

[0096] This embodiment provides a method for synchronously measuring a vehicle axle load spectrum and road surface response, including:

[0097] Acquire high and low level signals from sensing units located at the entrance and exit of the detection area, an axle load measurement signal from an axle load measurement unit located within the detection area, and a response measurement signal from a response measurement unit; wherein the axle load measurement unit includes a first sensor and a second sensor disposed in parallel, and a third sensor disposed between the two sensors and inclined at a certain angle;

[0098] Determine whether a vehicle enters or leaves the detection area based on the high and low level signals of the sensing unit, distinguish adjacent vehicles based on the high and low level signals at the entrance, and determine the axle load measurement signal and response measurement signal of each vehicle based on the high and low level signals at the entrance and exit;

[0099] The vehicle speed is obtained based on the time it takes for the vehicle to pass the first sensor and the second sensor, the wheelbase is obtained based on the vehicle speed and the time difference between adjacent axles of the vehicle passing the same sensor, and the vehicle model is determined based on the wheelbase;

[0100] Obtaining the vehicle axle load according to the vehicle speed and the axle load measurement signals measured when the vehicle passes the first sensor and the second sensor respectively;

[0101] Determine the driving trajectory based on the installation angle of the third sensor, the parallel distance between the first sensor and the second sensor, the time it takes to pass the second sensor and the third sensor, and the vehicle speed;

[0102] The position where the vehicle tire acts on the road surface is determined according to the driving trajectory, and the road surface response distribution is obtained according to the response measurement signal at the corresponding position.

[0103] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without any creative work are still within the scope of protection of the present invention.

Claims

1. A vehicle axle load spectrum and road surface response synchronous measurement system, characterized in that: include: The detection module includes sensing units located at the entrance and exit of the detection area, and an axle load measurement unit and a response measurement unit located within the detection area; the axle load measurement unit includes a first sensor and a second sensor disposed in parallel, and a third sensor disposed between the two sensors and inclined at a certain angle; The sensing unit includes a ground sensing coil and a ground sensing coil processing circuit. When a vehicle passes by the ground sensing coil, the output frequency of the ground sensing coil processing circuit changes. Specifically, a resonant circuit generates a sinusoidal signal, which is converted into a rectangular wave signal. When a vehicle passes by the ground sensing coil, the frequency of the rectangular wave signal changes. The change in the rectangular wave frequency is converted into a high / low level signal to indicate whether a vehicle has passed by the ground sensing coil. The data acquisition module is used to collect the axle load measurement signal, the response measurement signal and the high and low level signals of the sensing unit and store them in a dynamic array; The data analysis module is configured to extract the measurement signal of each unit from the dynamic array and obtain the changes in the axle load and driving trajectory of a certain vehicle model in response to the road surface based on the data of each unit; it includes: Distinguish adjacent vehicles based on the high and low level signals at the entrance, and determine the axle load measurement signal and response measurement signal of each vehicle based on the high and low level signals at the entrance and exit; The vehicle speed is obtained based on the time it takes for the vehicle to pass the first sensor and the second sensor, the wheelbase is obtained based on the vehicle speed and the time difference between adjacent axles of the vehicle passing the same sensor, and the vehicle model is determined based on the wheelbase; Obtaining the vehicle axle load according to the vehicle speed and the axle load measurement signals measured when the vehicle passes the first sensor and the second sensor respectively; Determine the driving trajectory based on the installation angle of the third sensor, the parallel distance between the first sensor and the second sensor, the time it takes to pass the second sensor and the third sensor, and the vehicle speed; Determine the position where the vehicle tire acts on the road surface according to the driving trajectory, and obtain the road surface response distribution according to the response measurement signal at the corresponding position; The distance between the driving trajectory of a single axle of the vehicle and the lane line y Represented as the vehicle's driving trajectory, based on the installation angle between the third sensor and the lane line , the parallel distance between the first sensor and the second sensor D , the time t2 of the second sensor and the time t1 of the third sensor, and the vehicle speed v , determine the driving trajectory y for: , .

2. A vehicle axle load spectrum and road surface response synchronous measurement system according to claim 1, characterized in that: The axle load measurement unit amplifies the output signals of the three sensors and converts them into voltage signals for collection by the data collection module; In the response measurement unit, a resistance signal that changes as the road surface strain changes is output, the resistance signal is converted into a voltage signal using a Wheatstone bridge, and the voltage signal is amplified by a differential operational amplifier circuit and then collected.

3. The vehicle axle load spectrum and road surface response synchronous measurement system according to claim 1, characterized in that: The data acquisition module and the data analysis module are operated synchronously; wherein, the data acquisition module continuously samples the data of each unit at a set sampling frequency and stores it in a dynamic array, and the data analysis module simultaneously extracts the data of each unit from the dynamic array and analyzes the data.

4. A vehicle axle load spectrum and road surface response synchronous measurement system according to claim 3, characterized in that: When the upper limit of the dynamic array capacity is reached, storage continues to be overwritten from the beginning of the dynamic array.

5. The vehicle axle load spectrum and road surface response synchronous measurement system according to claim 1, characterized in that: The time difference is obtained based on the time when each axle passes the first sensor and the second sensor. The vehicle speed under each axle is obtained based on the time difference and the parallel distance between the first sensor and the second sensor. The vehicle speed is obtained by averaging the speeds.

6. The vehicle axle load spectrum and road surface response synchronous measurement system according to claim 1, characterized in that: The wheelbase is obtained by multiplying the vehicle speed and the time difference between adjacent axles of the vehicle passing the same sensor.

7. The vehicle axle load spectrum and road surface response synchronous measurement system according to claim 1, characterized in that: Calculating the sum of all axle load measurement signals measured when one axle of the vehicle passes through the second sensor, and adding the sums of all axles to obtain the axle load measurement signal of the second sensor; Calculating the sum of all axle load measurement signals measured when one axle of the vehicle passes through the first sensor, and adding the sums of all axles to obtain the axle load measurement signal of the first sensor; The axle load measurement signal of the second sensor and the axle load measurement signal of the first sensor are averaged to obtain the axle load of the vehicle.

8. A method for synchronously measuring vehicle axle load spectrum and road surface response, characterized in that: include: Acquire high and low level signals from sensing units located at the entrance and exit of the detection area, an axle load measurement signal from an axle load measurement unit located within the detection area, and a response measurement signal from a response measurement unit; wherein the axle load measurement unit includes a first sensor and a second sensor disposed in parallel, and a third sensor disposed between the two sensors and inclined at a certain angle; The sensing unit includes a ground sensing coil and a ground sensing coil processing circuit. When a vehicle passes by the ground sensing coil, the output frequency of the ground sensing coil processing circuit changes. Specifically, a resonant circuit generates a sinusoidal signal, which is converted into a rectangular wave signal. When a vehicle passes by the ground sensing coil, the frequency of the rectangular wave signal changes. The change in the rectangular wave frequency is converted into a high / low level signal to indicate whether a vehicle has passed by the ground sensing coil. Determine whether a vehicle enters or leaves the detection area based on the high and low level signals of the sensing unit, distinguish adjacent vehicles based on the high and low level signals at the entrance, and determine the axle load measurement signal and response measurement signal of each vehicle based on the high and low level signals at the entrance and exit; The vehicle speed is obtained based on the time it takes for the vehicle to pass the first sensor and the second sensor, the wheelbase is obtained based on the vehicle speed and the time difference between adjacent axles of the vehicle passing the same sensor, and the vehicle model is determined based on the wheelbase; Obtaining the vehicle axle load according to the vehicle speed and the axle load measurement signals measured when the vehicle passes the first sensor and the second sensor respectively; Determine the driving trajectory based on the installation angle of the third sensor, the parallel distance between the first sensor and the second sensor, the time it takes to pass the second sensor and the third sensor, and the vehicle speed; Determine the position where the vehicle tire acts on the road surface according to the driving trajectory, and obtain the road surface response distribution according to the response measurement signal at the corresponding position; The distance between the driving trajectory of a single axle of the vehicle and the lane line y Represented as the vehicle's driving trajectory, based on the installation angle between the third sensor and the lane line , the parallel distance between the first sensor and the second sensor D , the time t2 of the second sensor and the time t1 of the third sensor, and the vehicle speed v , determine the driving trajectory y for: , .

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