KR102136576B1 - Road surface condition measuring device and road surface condition diagnosis system - Google Patents

Abstract

An objective of the present invention is to provide, in order to solve problems of the above-stated existing road surface condition measurement apparatus, a road surface condition diagnosis system capable of updating a road surface condition in real time by using a low-priced/miniaturized road surface measurement apparatus. According to one embodiment of the present invention, a road surface condition measurement apparatus provided on one side of a transportation means includes: an acceleration sensor combined with the front end of a suspension of the transportation means; a GPS sensing the current position of the transportation means; and a control part receiving x-axis, y-axis and z-axis direction acceleration values from the acceleration sensor, and receiving the current position of the transportation means from the GPS to store the same in a memory. Therefore, the road surface condition measurement apparatus is capable of providing an acceleration value of a position value stored in the memory such that the acceleration value is converted into a frequency area to be analyzed.

Description

Road surface condition measuring device and road surface condition diagnosis system

The present invention relates to a road surface condition measuring device and a road surface condition diagnosis system, and more specifically, an apparatus for measuring/diagnosing a road surface condition in a specific path by attaching an acceleration sensor and GPS to a vehicle or an electric kickboard, etc., and processing a sensing value. It's about the system.

Recently, the problem of road resurfacing has increased rapidly. Cracks and ruptures occur due to aging of roads, and there is no clear repackaging cycle for aging roads.

The cost of resurfacing is considerable, and the road surface condition has a great influence on not only the ride quality of the vehicle but also traffic safety, so it is necessary to establish a standard for diagnosis on the road surface condition for effective budget execution on road pavement. .

The conventional road surface condition diagnosis method was expensive, such as using a special vehicle or directly photographing and analyzing the road surface. In addition, the existing road surface conditioner was too slow to measure only a specific road surface.

Korean Patent No. 10-1883295 discloses a sensor that detects a road surface condition through an ultrasonic sensor, and Korean Patent Publication No. 2001-0072595 discloses a device that measures a road surface condition by irradiating a laser.

The above-described road surface condition measuring device can accurately measure the road surface condition, but is practically limited in measuring the road surface of a wide terrain. For example, in order to check the road surface condition of the entire Korean national highway, it is necessary to install the corresponding system on the entire national highway or to traverse the national national highway with vehicles with the corresponding equipment, which has a problem that it is unrealistic and time-consuming.

The problem to be solved by the present invention is to solve the problems of the conventional road surface condition measurement device as described above, a road surface condition measurement/diagnosis device that can update the road surface condition in real time using a low-cost/miniaturized road surface device measurement device/ It is to provide a system.

The present invention to solve the problem of the road surface condition measuring device, the road surface condition measuring device provided on one side of the vehicle, an acceleration sensor coupled to the front end of the suspension of the vehicle; GPS detecting the current position of the vehicle; It includes a control unit for receiving the acceleration values in the x-axis, y-axis and z-axis direction from the acceleration sensor, and receives the current position of the vehicle from the GPS and stores it in a memory; Provided is a road surface condition measuring device that provides an analysis by converting an acceleration value for a location value stored in the memory into a frequency domain.

내지 0.02

에서 형성되는 T1과, 20 Hz 내지 100 Hz 영역에서 0.009

내지 0.004

에서 형성되는 T2를 기준으로; 상기 PSD 데이터의 어퍼 인벨롭(Upper envelope)을 피팅한 값이 T1 이상인 경우 노면 상태 불량, 상기 PSD 데이터의 어퍼 인벨롭(Upper envelope)을 피팅한 값이 T1 미만 T2 초과인 경우 노면 상태 보통, 상기 PSD 데이터의 어퍼 인벨롭(Upper envelope)을 피팅한 값이 T2 이하인 경우 노면 상태 양호로 판단하는, 노면 상태 진단 시스템을 제공한다.In addition, in the road surface condition diagnosis system equipped with the road surface condition measuring apparatus as described above, the acceleration value for the position value stored in the memory is received, and the FFT and PSD convert the measured value in the time domain into the frequency domain; 0.05 in the range of 20 Hz to 100 Hz

To 0.02

T1 formed in and 0.009 in the range of 20 Hz to 100 Hz

To 0.004

Based on T2 formed in; If the value of fitting the upper envelope of the PSD data is T1 or more, the road surface condition is poor, and when the value of fitting the upper envelope of the PSD data is less than T1 and is greater than T2, the road surface condition is normal, the Provided is a road surface diagnosis system for determining that the road surface is good when the value of fitting the upper envelope of the PSD data is T2 or less.

In addition, the road surface condition diagnosis system equipped with the road surface condition measuring apparatus, the beacon is installed at a predetermined distance to the road network to receive an acceleration value for the location value stored in the memory; It provides a road condition diagnosis system, including a control server for collecting and analyzing data by receiving data from the beacon.

According to an embodiment of the present invention, it is possible to measure and analyze the road surface state by attaching to an existing transportation means, which can drastically reduce the introduction cost and introduction procedure/time of the public system (road analysis and road management). have.

In addition, it is possible to update the road surface in real time as the transportation means moves, so the accuracy of information is high compared to the existing method and apparatus for measuring the road surface.

And, by checking the level of the road surface step by step, it can guide what kind of management is needed for the road surface at a specific location.

In addition, by measuring the altitude and the rate of altitude change of the road, it is possible to provide the driver with difficulty and risk information of the operation.

1 is a graph analyzing data values of a road surface condition measuring apparatus according to an embodiment of the present invention.
2 is a schematic diagram showing components of a road surface condition measuring apparatus according to an embodiment of the present invention.
3 is a graph showing a criterion for diagnosing a road surface condition in a road surface condition measurement system according to an embodiment of the present invention.
4 is a graph showing PSD for data measured by varying the speed on the road surface in the road surface condition measurement system according to an embodiment of the present invention.
5 is a graph fitted to wrap the guide of the PSD measured in the road surface condition measurement system according to an embodiment of the present invention (Upper envelope).
6 is a graph showing PSDs of different roads at the same speed in a road surface condition measurement system according to an embodiment of the present invention.
7 is a graph fitting the upper portion of the guide in the graph of FIG. 6.

Hereinafter, various embodiments of this document will be described with reference to the accompanying drawings. However, this is not intended to limit the techniques described in this document to specific embodiments, and should be understood to include various modifications, equivalents, and/or alternatives of embodiments of the document. . In connection with the description of the drawings, similar reference numerals may be used for similar elements.

In this document, expressions such as "have," "can have," "includes," or "can contain," the existence of a corresponding feature (eg, a component such as a numerical value, function, operation, or part) And does not exclude the presence of additional features.

In this document, expressions such as “A or B,” “at least one of A or/and B,” or “one or more of A or/and B”, etc. may include all possible combinations of the items listed together. . For example, “A or B,” “at least one of A and B,” or “at least one of A or B,” (1) includes at least one A, (2) includes at least one B, Or (3) all cases including both at least one A and at least one B.

Expressions such as "first," "second," "first," or "second," as used herein may modify various components, regardless of order and/or importance, and denote one component. It is used to distinguish from other components, but does not limit the components. For example, the first user device and the second user device may indicate different user devices regardless of order or importance. For example, the first component may be referred to as a second component without departing from the scope of rights described in this document, and similarly, the second component may be referred to as a first component.

Some component (eg, first component) is “operatively or communicatively coupled with/to” another component (eg, second component) or “accessed When referred to as "connected to", it should be understood that any component may be directly connected to the other component, or may be connected through another component (eg, a third component). On the other hand, when it is mentioned that a component (eg, the first component) is “directly connected” or “directly connected” to another component (eg, the second component), the component and the component It can be understood that no other component (eg, third component) exists between the other components.

As used herein, the expression "configured to" is, depending on the situation, for example, "having the capacity to" ," "designed to," "adapted to," "made to," or "capable of" can be used interchangeably. The term "configured (or set) to" may not necessarily mean only "specifically designed to" in hardware. Instead, in some situations, the expression "device configured to" may mean that the device "can" with other devices or parts. For example, the phrase “processors configured (or set) to perform A, B, and C” means by executing a dedicated processor (eg, an embedded processor) to perform the operation, or one or more software programs stored in the memory device. , It may mean a general-purpose processor (for example, a CPU or an application processor) capable of performing the corresponding operations.

Terms used in this document are only used to describe specific embodiments, and may not be intended to limit the scope of other embodiments. Singular expressions may include plural expressions unless the context clearly indicates otherwise. Terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by a person skilled in the art described in this document. Among the terms used in the present document, terms defined in the general dictionary may be interpreted as having the same or similar meaning in the context of the related art, and have an ideal or excessively formal meaning, unless explicitly defined in this document. Is not interpreted as In some cases, even terms defined in this document cannot be interpreted to exclude embodiments of this document.

Various modifications can be made by those skilled in the art to which the present invention pertains without departing from the gist of the present invention as claimed in the claims of the present invention. It should not be understood individually from the perspective.

1. Fast Fourier Transform

The Fast Fourier Transform (FFT) is an efficient algorithm that quickly performs a Discrete Fourier Transform (DFT) and its inverse transform. FFT is used in many fields, from digital signal processing to algorithms for rooting partial differential equations.

이 복소수라고 가정할 때, DFT는 다음과 같이 정의한다.

Assuming that this is a complex number, DFT is defined as follows.

)의 연산이 필요하지만, FFT를 이용하면 O(

)의 연산만으로 가능하다.

이 합성수일 경우 그 소인수 분해를 이용하여 연산횟수를 줄일 수는 있지만, FFT를 사용하면

이 소수일 경우에도 O(

)번의 연산횟수를 보장한다.If you calculate this expression by definition, O(

), but using FFT, O(

).

In the case of this composite number, it is possible to reduce the number of operations by using the prime factorization, but if FFT is used,

O(

) Is guaranteed.

2. Energy spectral density

Energy Spectral Density (PSD) is a unit that measures the power content versus frequency of a signal. PSD is commonly used to characterize broadband random signals. The amplitude of the PSD is normalized by the spectral resolution used to digitize the signal. In other words, PSD represents the magnitude of energy for each frequency when energy represented by a time function is converted into a frequency function through a Fourier transform. When the energy of the time function transmitted through the seismic wave is converted into a frequency function, it means the energy distribution expressed as a frequency function. As the term density means, if energy values for each frequency are summed for all frequencies, the total energy transmitted through disturbance can be obtained. Energy spectral density is widely used in engineering fields dealing with the behavior of objects due to disturbances, such as electromagnetic, acoustic, and structural vibrations.

For PSD of vibration data, the amplitude unit of [g^2/Hz] is used. This unit may not seem intuitive at first, but it allows random data to be superimposed and compared independently of the spectral resolution used to measure this data.

3. Nyquist theorem

In the case of a function having a frequency of a limited band, it is a theory that taking an appropriate sampling interval can completely reproduce without losing any information in the sampling process. At this time, at least two samples must be present in order to properly represent a cycle of a specific frequency component. This is also called Shannon theorem, Nyquist theorem.

는 신호의 최대주파수 성분의 두 배 이상이 되어야 한다. 이는

/2 이상의 주파수 성분에서는 중첩(Folding) 현상이 발생하여 Aliasing 현상이 발생하기 때문이며, 이때

/2를 중첩(Folding) 주파수 또는 Nyquist 주파수라 부른다.Sampling frequency according to Nyquist Theorem

Should be more than twice the maximum frequency component of the signal. this is

This is because an aliasing phenomenon occurs because a folding phenomenon occurs in a frequency component of /2 or more.

The /2 is called the overlapping frequency or the Nyquist frequency.

In digital signal processing, when an input signal is digitized by an analog digital converter (ADC), it is recorded as N discrete values.

), Nyquist 주파수(

), 분해능 주파수(Frequency Resolution,

) 사이의 기본적인 관계식은 다음과 같다.Sampling frequency(

), Nyquist frequency (

), Frequency Resolution,

) Is as follows.

The experimentally measured acceleration data is analyzed in the frequency domain. Since the sampling time of the sensor shows a difference from the value shown in the actual specification sheet, the sampling time is reversed based on the experiment time to analyze the signal.

The data obtained in the experiment were analyzed with reference to the above theories, and the criteria used for classification of road surfaces in this process include ISO and IRI road roughness standards.

4. Matlab Translate

In the Matlab analysis, acceleration data over time obtained from the experiment was converted to FFT and then converted to PSD. In order to compare data on different road surfaces, signal data was classified together with a guide. PSD data was used for the classification of the road surface, and the ISO classification method was devised for closer classification, so that a more detailed condition diagnosis could be performed.

The FFT and PSD MATLAB codes used in the analysis are as follows.

%Compute FFT & PSD

Fs = fActual; % Actual sample rate of the data in Hertz

x = datalist(:,2); % z-axis accleration data

N = length(x); % total length of x

freq = 0:Fs/length(x):Fs/2; %frequency bins (nyquist rule)

xdft = fft(x); % Fast-Fourier-Transfrom

xdft = xdft(1:floor(N/2)+1);

psdx = (1/(Fs*N)) * abs(xdft).^2; % amplitude of FFT^2 divided by Hz (PSD)

psdx(2:end-1) = 2*psdx(2:end-1);

psdx = psdx';

xdft = 1/length(x).*xdft;

xdft(2:end-1) = 2*xdft(2:end-1);

xdft = xdft';

phase = unwrap(angle(xdft)); % phase

xdft = abs(xdft); % amplitude

5. According to vehicle speed PSD value compare

In an embodiment of the present invention, the acceleration sensor is attached to the electric kickboard to measure the acceleration value more accurately, and data is measured. The transport means to which the present invention can be applied may include land transport means moving in contact with the ground (road surface) such as an automobile, a tracked vehicle, a bicycle, a motorcycle, and an electric kickboard.

30

)에서 그 차이가 두드러지는 것을 확인할 수 있다. 고주파 영역의 경우, 그래프가 많이 겹쳐 보임을 확인할 수 있다.The graph of FIG. 4 is an experimental result of interpreting how the PSD value according to frequency changed when data was measured by varying the speed on each road surface (FIGS. 4A and 4B ). It was confirmed that the higher the speed, the larger the value, especially the low frequency (1

30

), you can see the difference is noticeable. In the high-frequency region, it can be seen that the graphs are superimposed.

For a more smooth comparison, as shown in FIG. 5, a guide surrounding the PSD was fitted and compared through this. Through this, it can be seen that as the speed increases, the PSD value of the acceleration data increases.

At this time, there were cases where the difference was not large depending on the measured data. However, also in this case, the PSD value tends to increase as the speed increases.

6. According to the road surface condition PSD value compare

100Hz에서의 그래프 도시하였다.Since we found that the speed affects the value of the PSD as a result of the above, we compare the PSD of the data measured at a speed of 15 km to compare data run at the same speed. 6, it can be seen that the PSD value is larger as the road surface is rougher, but it is difficult to confirm this because the graph overlaps. Therefore, drawing the graph again through the guide analysis is shown in FIG. 7. At this time, the frequency that best represents the characteristic of the graph, 20

The graph at 100 Hz is shown.

The graph shows that A is a very good road, B and E are normal roads, and finally C and D are bad roads.

Table 1 shows PSD values for each road surface.

Road surface

]PSD[

] A 0.002~0.001 B 0.02~0.011 C 0.06~0.035 D 0.09~0.05 E 0.011~0.006

7. Road classification criteria setting

By comparing actual road conditions and PSD values, the road classification criteria can be set as shown in Table 2 below. It can be regarded as poor when the road surface measurement/conversion value is above T1, normal when between T1 and T2, and good when below T2.

Threshold

]PSD[

] state T1 0.05~0.02 Poor-Good T2 0.009~0.004 Good-excellent

The reference value can be illustrated as in FIG. 3. The road A illustrated in FIG. 3 is located between T1 and T2, so it can be considered that the road condition is normal.

8. Example

According to an embodiment of the present invention, a road surface condition measuring device provided on one side of a transportation means, comprising: an acceleration sensor coupled to a front end of the suspension of the transportation means; GPS detecting the current position of the vehicle; It includes a control unit for receiving the acceleration values in the x-axis, y-axis and z-axis direction from the acceleration sensor, and receives the current position of the vehicle from the GPS and stores it in a memory; Provided is a road surface condition measuring device that provides an acceleration value for a position value stored in the memory to be converted into a frequency domain for analysis.

2 is a schematic diagram showing components of a road surface condition measuring apparatus according to an embodiment of the present invention. The device was manufactured using an Arduino Uno board (control unit), HC-06 (Bluetooth module, communication unit), MPU-6050 (acceleration sensor) and battery.

In order to analyze the stored data, a wired/wireless communication means may be provided to transmit data to an analysis computer or the like.

As the battery, a battery of a transportation means can be used. As a result, it is possible to continuously measure the road surface in a situation in which the vehicle operates normally without a separate battery replacement.

In the above description, the "acceleration sensor coupled to the front end of the suspension of the transportation means" is difficult to measure a value reflecting the actual road surface due to the wheels and the suspension devices provided inside the vehicle in the case of a vehicle, etc. It means that the accelerometer is attached before the coupling part of. In the case of a vehicle having no suspension, such as an electric kickboard or a bicycle, or insignificant effect, it can be attached anywhere in a position that is not affected by the control unit (handle). For example, it can be attached to the bottom of the footboard of the electric kickboard.

The GPS and acceleration sensors can simultaneously store data values and store acceleration values at specific locations. Each time a predetermined distance is moved to enable data analysis for a specific section, the section may be cut to store data.

The present invention may be basically provided on a newly manufactured vehicle, but can be simply used by simply installing it on an existing vehicle. Components such as the acceleration sensor and the control unit have a significantly lower weight and smaller size than the vehicle body, and thus do not affect the driving performance of automobiles.

내지 0.02

에서 형성되는 T1과, 20 Hz 내지 100 Hz 영역에서 0.009

내지 0.004

에서 형성되는 T2를 기준으로; 상기 PSD 데이터의 어퍼 인벨롭(Upper envelope)을 피팅한 값이 T1 이상인 경우 노면 상태 불량, 상기 PSD 데이터의 어퍼 인벨롭(Upper envelope)을 피팅한 값이 T1 미만 T2 초과인 경우 노면 상태 보통, 상기 PSD 데이터의 어퍼 인벨롭(Upper envelope)을 피팅한 값이 T2 이하인 경우 노면 상태 양호로 판단하는, 노면 상태 진단 시스템을 제공한다.In addition, in the road surface condition diagnosis system equipped with the road surface condition measuring apparatus as described above, the acceleration value for the position value stored in the memory is received, and the FFT and PSD convert the measured value in the time domain into the frequency domain; 0.05 in the range of 20 Hz to 100 Hz

To 0.02

T1 formed in and 0.009 in the range of 20 Hz to 100 Hz

To 0.004

Based on T2 formed in; If the value of fitting the upper envelope of the PSD data is T1 or more, the road surface condition is poor, and when the value of fitting the upper envelope of the PSD data is less than T1 and is greater than T2, the road surface condition is normal, the Provided is a road surface diagnosis system for determining that the road surface is good when the value of fitting the upper envelope of the PSD data is T2 or less.

The ranges of T1 and T2 may be determined with reference to FIG. 3. As the frequency domain increases (from 20 Hz to 100 Hz), the amplitude value may be reduced to form within the above numerical range. In order to be easily carried out by a person skilled in the art, scales and examples, etc. are shown in detail in FIG. 3.

The road surface condition diagnosis system as described above can be used in road traffic construction or government offices.

In the related art, there have been many cases in which the road surface is repaired lately by complaints that the road condition is bad, and it is impossible to respond promptly and takes a long time to repair because it consists of the steps of filing a complaint-checking the road condition and repairing the road. Had its limits.

As described above, in the case of distinguishing the road surface grade in the road surface condition diagnosis system, if the road surface condition is bad, immediate repair is performed, and when the road surface condition is normal, it can be checked at a specific cycle.

On the road with a large amount of accumulated traffic, not only is there a lot of data accumulated, but the fact that the road damage is rapidly progressed in proportion to the amount of traffic, a realistic and effective road surface diagnosis is possible through the system according to the present invention.

In addition, the road surface condition diagnosis system equipped with the road surface condition measuring apparatus, the beacon is installed at a predetermined distance or point in the road network to receive an acceleration value for the location value stored in the memory; It provides a road condition diagnosis system, including a control server for collecting and analyzing data by receiving data from the beacon.

In the description of the "predetermined distance in the road network", "distance" is not a road, but a distance. Since the unit cost of the road surface condition measuring device itself is low, it can be installed in a large number of vehicles, so the distance can be minimized.

Beacons are preferably provided at gas stations, parking lots, roads, government offices, tunnel entry/exit, stop lines at intersections, and the like. After a vehicle or the like moves and accumulates data by a predetermined distance, the data stored in the vehicle during the main/stop is transmitted to a beacon, so that the control server can collect data values.

Beacons are buried under the floor of a parking line in a gas station or parking lot, and data can be transmitted through wireless communication between the communication unit and the beacon provided in the control unit.

After transferring data to the beacon, data is deleted from the memory to secure capacity.

In the control server, road surface diagnosis information and road pavement/repair history are stored. In addition, data reception date information may be stored for each road section to measure data collection frequency for each road.

In another embodiment of the present invention, an altitude sensor may be further provided in addition to the acceleration sensor.

It is possible to grasp the topographic information of the road by matching the position values of the altitude sensor and GPS. For example, it is possible to determine the slope of a road by checking the rate of change in altitude of a specific road section. The altitude sensor is not related to the suspension of the vehicle, so it can be attached to any vehicle.

The control server can display a map showing the road network, and display the status for each road section on the display screen. Defective status is marked in red, normal status is indicated in yellow, and good status is indicated in blue, so that roads requiring inspection/repair can be checked at a glance

When a specific road section is selected on the map, it shows the altitude of the road, the rate of altitude change at a specific point, and the average rate of altitude change in the section, so that the shape of the road or the degree of slope can be grasped. Through this, it is possible to avoid the corresponding road in navigation attached to or embedded in the vehicle when the driver is immature, or when the output of the vehicle is insufficient to rise above a specific altitude.

In addition, in another embodiment of the present invention, the acceleration sensor coupled to the front end of the suspension of the vehicle; GPS detecting the current position of the vehicle; It includes a control unit for receiving the acceleration values in the x-axis, y-axis and z-axis direction from the acceleration sensor, and receives the current position of the vehicle from the GPS and stores it in a memory; In the road surface condition diagnosis method using a road surface condition diagnosis system equipped with a road surface condition measuring device for converting and analyzing the acceleration value for the position value stored in the memory to the frequency domain, the road surface condition diagnosis system, A beacon installed at a predetermined distance and receiving an acceleration value for a location value stored in the memory; And a control server for collecting and analyzing data by receiving data from the beacon; A data measurement step of measuring an acceleration value in the road surface condition measurement device; A data storage step of storing the acceleration value and the position value in a memory after the data measurement step; A data transmission step of transmitting data to a control server via a beacon after the data storage step; A data conversion step of converting acceleration values into FFT and PSD after the data transmission step; A road surface diagnosis step of classifying road grades through the converted data after the data conversion step; After the road surface condition diagnosis step, the road surface diagramming step of displaying the status of each road grade in different colors on the map shown on the control server display; After the road surface painting step, the inspection target notification step showing the inspection target notification for a road in bad condition or a drawing in which inspection/paving/repair history has passed a predetermined period or more; After the inspection target notification step, when the inspection / packaging / repair information for a specific road is input to update the information in the control server database, the pavement / repair input step shown on the display; including, providing a method for diagnosing road conditions .

Claims (3)

An acceleration sensor provided on one side of the vehicle and coupled to the front end of the suspension of the vehicle; GPS detecting the current position of the vehicle; It includes a control unit for receiving the acceleration values in the x-axis, y-axis and z-axis direction from the acceleration sensor, and receives the current position of the vehicle from the GPS and stores it in a memory; A road surface state measuring device is provided to convert and analyze an acceleration value for a location value stored in the memory into a frequency domain; In the road condition diagnosis system,
Receiving an acceleration value for a position value stored in the memory, and converting a measured value in the time domain into a frequency domain through FFT and PSD;
0.05 in the range of 20 Hz to 100 Hz

To 0.02

T1 formed in and 0.009 in the range of 20 Hz to 100 Hz

To 0.004

Based on T2 formed in;
If the value of fitting the upper envelope of the PSD data is T1 or more, the road surface is bad,
When the value fitting the upper envelope of the PSD data is less than T1 and exceeds T2, the road surface state is usually
When the value fitting the upper envelope of the PSD data is T2 or less, the road surface diagnosis system determines that the road surface is good delete The method according to claim 1,
A beacon installed at a predetermined distance in a road network and receiving an acceleration value for a location value stored in the memory;
A road surface condition diagnosis system including a control server for receiving data from the beacon and collecting and analyzing data.

Images