KR102052849B1 - APPARATUS FOR DETECTING RAIL DEFECT BY USING MULTI-CHANNEL EDDY CURRENT SENSOR AND Sensor calibrating METHOD THEREOF AND RAIL DEFECT DETECTING METHOD - Google Patents

Abstract

The present specification discloses an apparatus and method for detecting a rail defect improved compared to the prior art. According to the present specification, the apparatus comprises: an encoder moving along an inspection surface of a rail to be inspected and outputting data for a moving distance; a communication module transmitting/receiving data with an external device; a plurality of eddy current sensors; a frequency generator outputting an alternating signal to the eddy current sensors; and a processor electrically connected to the encoder, communication module, frequency generator, and eddy current sensors. The processor may control the frequency generator to output an alternating current having a predetermined frequency, and control a plurality of signals outputted by the eddy current sensors and data outputted from the encoder to be transmitted to the outside through the communication module.

Description

Rail defect detection device, sensor calibration method and defect detection method using multi-channel eddy current sensor

The present invention relates to an apparatus capable of detecting rail defects, a sensor calibration method and a defect detection method, and more particularly, an apparatus capable of detecting rail defects using a multi-channel eddy current sensor, a sensor calibration method and a defect detection method. It is about.

The eddy current test is a technique widely used for cracking of metals, and is a non-destructive test technique for electrically detecting a change in conductivity (impedance change). The principle of the technology is that when an alternating current generated from eddy current equipment is applied to the sensor coil, a magnetic field is generated as the current flows through the coil. At this time, when a metal body is close to the sensor, a eddy current is generated in a direction perpendicular to the direction of the magnetic field in the metal subjected to the magnetic field. This is the eddy current, and the size and shape of the eddy current flowing when the crack is changed can be checked for cracks. The above technique can be applied to defect inspection of railway rails.

1 is an exemplary view of a rail defect inspection equipment according to the prior art.

Referring to Figure 1, the rail defect inspection equipment according to the prior art performs the inspection on the rail head (inspected 'inspection surface') using an eddy current sensor. In order to inspect the wide head of a rail with an eddy current sensor, the position of the sensor must be moved several times and the same rail must be repeatedly tested. Due to the rail defect inspection equipment according to the prior art, the crack depth and length of the rail to be inspected are possible, but the three-dimensional defect shape of the rail to be inspected, such as the width of the crack, cannot be analyzed and evaluated. In addition, since the rail defect inspection apparatus according to the prior art inspects the eddy current sensor after moving the position according to the inspection position, there is a problem in that the data inspected after the movement cannot be matched with each other on the same line of the rail.

2 is a structural diagram of an eddy current sensor according to the prior art.

Referring to FIG. 2, an absolute coil type sensor having one cylindrical coil structure and a differential coil type sensor adjacent to two cylindrical coils may be identified. The eddy current sensor according to the prior art has an advantage that it is easy to manufacture, but it is sensitive to the distance change (Lift Off) between the eddy current sensor and the test object (rail) and is vulnerable to axial defects.

In order to calibrate the output value according to the distance between the four eddy current sensors and the specimen, the conventional rail defect inspection equipment uses a sheet of 0.1 to 0.2 mm for three to five artificial defects and uses 0.5 to 1.0. After the distance change (Lift-off) between the eddy current sensor and the test surface of mm, the signal is repeatedly measured and a calibration transfer function is derived. However, if one of the calibration signal measurements is incorrectly measured, there is a difficulty in starting from the beginning. In addition, due to the deviation between the weld between the rail and the dissimilar material rail signal, it is difficult to collectively inspect.

Patent Application Publication No. 10-1713545

It is an object of the present disclosure to provide an apparatus and method for detecting rail defects that is improved over the prior art.

The present specification is not limited to the above-mentioned task, and other tasks not mentioned will be clearly understood by those skilled in the art from the following description.

Rail defect detection apparatus according to the present specification for solving the above problems is an encoder for outputting data on the movement distance while moving along the inspection surface of the inspection target rail; Communication module for transmitting and receiving data with an external device; A plurality of eddy current sensors; A frequency generator for outputting an AC signal to the plurality of eddy current sensors; And a processor electrically connected to the encoder, the communication module, the frequency generator, and a plurality of eddy current sensors, wherein the processor controls the frequency generator to output an alternating current having a preset frequency. A plurality of signals output from the eddy current sensor and data output from the encoder can be controlled to be transmitted to the outside through the communication module.

According to one embodiment of the present specification, the number of the eddy current sensors may be sixteen.

According to one embodiment of the present specification, the eddy current sensor may have a form in which two coils cross at right angles.

The sensor calibration method according to the present specification for solving the above problems is a sensor calibration method of a rail defect detection device including a plurality of eddy current sensors, the data passing through the defect formed in the sample rails a plurality of eddy current sensors (hereinafter ' Receiving reference data '); A phase correction step of matching phases of a plurality of eddy current sensor signals included in the reference data; And an amplitude correction step of matching amplitudes of the plurality of eddy current sensor signals included in the reference data.

The sensor calibration method of the rail defect detecting apparatus according to the present specification comprises: (a) removing noise of the reference data after the step of receiving the reference data; And

(b) removing the tilting tendency of the reference signal from which the noise is removed.

According to one embodiment of the present specification, the phase correction step may be a step of correcting phases of a plurality of eddy current sensor signals with a preset reference phase value.

According to one embodiment of the present specification, the amplitude correction step includes setting a signal having the largest amplitude among a plurality of eddy current sensor signals as a reference amplitude value, and correcting the amplitudes of the remaining eddy current sensor signals to the reference amplitude value. Can be.

Rail defect detection method according to the present specification for solving the above problems is a method for detecting a defect of the rail by using a plurality of eddy current sensors, the plurality of eddy current sensors passed through the rail to be examined (hereinafter referred to as' test data Receiving inspection data receiving '); A defect length estimating step of estimating a length of a defect using an amplitude value of the inspection data; A defect depth estimating step of estimating a depth of a defect using a phase value of the inspection data; And a defect width estimation step of estimating the width of the defect using an eddy current sensor signal having an amplitude equal to or greater than a preset threshold value among the inspection data.

According to one embodiment of the present specification, the defect length estimating step may be a step of estimating a length of a defect through the following equation.

Length (mm) = Ticks (b-a) * ODOmeter (mm)

Length (mm): estimated length of defect

a, b: the point where the slope of the amplitude signal is '0'

Ticks (b-a): distance between points with slope '0'

-ODOmeter (mm): Travel distance of sensor calculated through encoder data

According to one embodiment of the present specification, the defect depth estimating step may be a step of estimating a length of a defect through the following equation.

Depth (mm) = a _One * PhaseAngle (deg) + a ₀

Depth (mm): estimated depth of defect

PhaseAngle (deg): Phase of eddy current sensor signal

a ₁ : slope value collected through standard defect test

a ₀ : intercept value collected through standard defect test

According to one embodiment of the present specification, the step of estimating the defect area may be a step of estimating the length of a defect through the following equation when there is one eddy current sensor signal having an amplitude greater than or equal to the threshold value.

Width (mm) = (S _One  * R _m ) / (aD ²  + bD + c)

Width (mm): estimated width of defect

S ₁ : Diameter of the sensor

R _m : Magnetic force of the defect signal

-D: expected depth of defect

a, b, c: coefficient values collected through standard defect tests

According to another embodiment of the present disclosure, the step of estimating the defect area may be a step of estimating the length of a defect through the following equation when two or more eddy current sensor signals having an amplitude greater than or equal to the threshold value are present.

Width (mm) = (N _Valid  * S _i ) + (N _Valid -1) * W _int  -(S _i  -W _BL )-(S _i  -W _BR )

W _BL  = (S _i  * R _BL ) / R _MAX

W _BR  = (S _i  * R _BR ) / R _MAX

Width (mm): estimated width of defect

-N _Valid : Number of eddy current sensors with amplitude above threshold

S _i : Diameter of the i th sensor

W _int : The distance between two eddy current sensors with an amplitude above the threshold

-R _MAX : Maximum value of magnetic peak

-R _BL : The peak value of magnetic force above the threshold among the sensors located on the left based on the maximum peak value of magnetic force

-R _BR : Magnetic force peak value over threshold among sensors located on the right side based on the maximum magnetic field peak value

Other specific details of the invention are included in the detailed description and drawings.

According to an aspect of the present disclosure, unlike the prior art, it is possible to inspect the side and the upper surface of the rail at once without changing the position of the eddy current sensor.

According to another aspect of the present specification, the position and depth of the rail defect may be inspected in real time, and the shape of the defect may be analyzed in three dimensions.

According to another aspect of the present specification, by adjusting the phase and amplitude values output by the eddy current sensor by using a sample rail having one artificial defect, without using a separate calibration sheet for the calibration of the sensor before measuring the defect The procedure is significantly simpler than the prior art.

Effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the following description.

1 is an exemplary view of a rail defect inspection equipment according to the prior art.
2 is a structural diagram of an eddy current sensor according to the prior art.
3 is a block diagram schematically illustrating a configuration of an apparatus for detecting a rail defect according to an exemplary embodiment of the present specification.
4 is an exemplary diagram of a frequency generator according to the present specification.
5 is an exemplary view of an eddy current sensor according to the present specification.
6 is an exemplary view in which 16 eddy current sensors according to an embodiment of the present disclosure are arranged on a rail to be inspected.
7 is an exemplary view in which the eddy current sensor according to the exemplary embodiment of the present specification is in the form of '+'.
8 is a flowchart illustrating a sensor calibration method according to an embodiment of the present specification.
9 is an illustration of a sample rail that may be used for sensor calibration.
10 is an exemplary diagram of reference data.
11 is an exemplary diagram of a process of removing noise of reference data.
12 is an exemplary diagram of a process of removing a tilt tendency of reference data.
13 is a reference diagram of phase and amplitude correction.
14 illustrates an example of matching data sensed with color patterns after phase and amplitude correction.
15 is a flowchart illustrating a rail defect detection method according to an embodiment of the present specification.
16 is a reference diagram of a defect length estimation step according to the present specification.
17 is a reference diagram of a defect depth estimation step according to the present specification.
18 is a reference diagram of a defect area estimation step when there is one eddy current sensor signal having an amplitude greater than or equal to a threshold according to an embodiment of the present specification.
19 is a reference diagram of a defect area estimation step when two or more eddy current sensor signals having an amplitude or more according to another embodiment of the present specification have an amplitude.

Advantages and features of the invention disclosed herein, and methods of achieving them will be apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below, but may be implemented in various forms, and the present embodiments are merely provided to make the disclosure of the present disclosure complete, and those of ordinary skill in the art to which the present disclosure belongs. It is provided to fully inform the skilled person (hereinafter, "the person in charge") the scope of the present specification, the scope of the present specification is defined only by the scope of the claims.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the scope of the present disclosure. In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, "comprises" and / or "comprising" does not exclude the presence or addition of one or more other components in addition to the mentioned components. Like reference numerals refer to like elements throughout, and "and / or" includes each and all combinations of one or more of the mentioned components. Although "first", "second", etc. are used to describe various components, these components are of course not limited by these terms. These terms are only used to distinguish one component from another. Therefore, of course, the first component mentioned below may be a second component within the technical spirit of the present invention.

Unless otherwise defined, all terms used in the present specification (including technical and scientific terms) may be used in a sense that can be commonly understood by those skilled in the art to which this specification belongs. In addition, terms that are defined in a commonly used dictionary are not ideally or excessively interpreted unless they are specifically defined clearly.

The spatially relative terms " below ", " beneath ", " lower ", " above ", " upper " It can be used to easily describe a component's correlation with other components. Spatially relative terms are to be understood as including terms in different directions of components in use or operation in addition to the directions shown in the figures. For example, when flipping a component shown in the drawing, a component described as "below" or "beneath" of another component may be placed "above" the other component. Can be. Thus, the exemplary term "below" can encompass both an orientation of above and below. Components may be oriented in other directions as well, so spatially relative terms may be interpreted according to orientation.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Although embodiments of the present disclosure have been described with reference to the accompanying drawings, those skilled in the art will understand that the present disclosure can be implemented in other specific forms without changing the technical spirit or essential features. Could be. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

First, the rail defect detection apparatus according to the present specification will be described.

3 is a block diagram schematically illustrating a configuration of an apparatus for detecting a rail defect according to an exemplary embodiment of the present specification.

Referring to FIG. 3, the rail defect detecting apparatus 100 according to an exemplary embodiment of the present specification includes an encoder 110, a processor 120, a communication module 130, a frequency generator 140, and a plurality of eddy current sensors 150. ) May be included.

The encoder 110 may output data on a moving distance while moving along the inspection surface of the inspection target rail. An encoder is a device used to measure the rotational speed (angular velocity, etc.) of a rotating object. When the rail defect detecting apparatus 100 according to the present specification moves along the inspection target rail, the rotation shaft of the encoder 110 may be connected to rotate together according to the moving distance. By using the information output from the encoder 110, it is possible to know the location of the defect, the length of the defect, etc. on the inspection target rail.

The processor 120 may be electrically connected to the encoder 110, the communication module 130, the frequency generator 140, and the plurality of eddy current sensors 150. The processor 120 may control the frequency generator 140 to output an alternating current having a preset frequency. The processor 120 may receive signals output from the encoder 110 and the plurality of eddy current sensors 150. The processor 120 may control to transmit a plurality of signals output from the eddy current sensors 150 and signals output from the encoder 110 to the outside through the communication module 130.

The external device that receives data from the communication module 130 refers to a host device that controls the operation of the rail defect detection device according to the present specification or stores and analyzes the received data. The external device may be a device capable of executing a sensor calibration method or a rail defect detection method of the rail defect detection apparatus according to the present specification.

The frequency generator 140 may output an AC signal to the plurality of eddy current sensors 150.

4 is an exemplary diagram of a frequency generator according to the present specification.

Referring to FIG. 4, a table value of frequencies to be generated may be stored in the memory Mem. A phase may be generated in a phase accumulator according to a default value of a phase calculation set in an adder. Thereafter, the output data of the memory may be converted into an analog signal by a converter (D / A) to generate a frequency. The frequency of the signal generated by the frequency generator 140 according to the embodiment shown in FIG. 4 is very stable in phase and amplitude characteristics according to temperature.

The plurality of eddy current sensors 150 may include a coil. As the current flows through the coil by the AC signal output from the frequency generator, a magnetic field is generated. The magnetic field may affect the rail to be inspected. In the inspection target rail, a eddy current may be generated in a direction perpendicular to the direction of the magnetic field. The eddy current flowing in the rail generates a magnetic field, and the magnetic field generated by the eddy current again affects the current flowing in the eddy current sensor. If the rail to be inspected is defective, the size and shape of the eddy currents flowing through the rail may change. Therefore, when there is no defect in the inspection target rail, the current flowing through the eddy current sensor and the current flowing through the eddy current sensor when the inspection target rail is defective may be determined to determine whether the rail is defective.

5 is an exemplary view of an eddy current sensor according to the present specification.

Referring to FIG. 5, the eddy current sensor 150 may include a circuit protection device. The circuit protection device includes an over-voltage protection circuit and a high-frequency high voltage protection circuit such as EMI due to the potential difference between the sensor coils directly contacting the rail surface and the heterogeneous voltage flowing on the rail surface. ) May be included.

According to one embodiment of the present specification, the number of the eddy current sensors may be sixteen.

FIG. 6 is an exemplary view in which sixteen eddy current sensors are arranged on a rail to be inspected according to an exemplary embodiment of the present specification.

Referring to FIG. 6, in the sixteen eddy current sensors 150, the centers of the respective eddy current sensors may be disposed on different longitudinal axes of the rail to be inspected. In addition, the sixteen eddy current sensors 150 has four eddy current sensors in one group to form a total of four groups, and the centers of the four eddy current sensors included in each group are on the same axis in the width direction of the inspection target rail. The centers of the four groups may be arranged on different width directions of the rail to be inspected.

According to one embodiment of the present specification, the eddy current sensor 150 may have a form in which two coils cross at right angles.

7 is an exemplary view in which the eddy current sensor according to the exemplary embodiment of the present specification is in the form of '+'.

Referring to Figure 7, it can be seen that the coil and the eddy current pattern of the '+' shape is shown. The coil of the '+' type may operate differentially. The differential operation reduces the effect of the distance between the rail and the eddy current sensor (Lift-Off effect), the defect detection characteristics in the width direction, the length direction and the diagonal direction are good, and the material characteristics in the rail welded part and manganese rail Since the signal change is not large, constant detection characteristics can be obtained.

Hereinafter, a sensor calibration method (hereinafter, referred to as a sensor calibration method) of the above-described rail defect detection apparatus will be described. Since each eddy current sensor may have a different sensitivity, the direction and magnitude of the detected signal are different. For accurate inspection, it is necessary to match the amplitude and phase of each eddy current sensor used. This is called calibration. In describing the sensor calibration method according to the present specification, since the above-described rail defect detection apparatus is used, repeated description of each configuration will be omitted.

8 is a flowchart illustrating a sensor calibration method according to an embodiment of the present specification.

Referring to FIG. 8, the sensor calibration method according to the exemplary embodiment of the present specification may largely include a reference data receiving step S10, a phase correction step S20, and an amplitude correction step S30.

First, in step S10, the plurality of eddy current sensors 150 may receive data (hereinafter referred to as 'reference data') passing through a defect formed in the sample rail.

9 is an illustration of a sample rail that may be used for sensor calibration.

9, a defect may be formed in the sample rail. Ideally, multiple eddy current sensors should output the same value when sensing the same fault.

10 is an exemplary diagram of reference data.

Referring to FIG. 10, 16 eddy current sensors analyze data obtained by inspecting a sample rail in a horizontal direction (X data) and a vertical direction (Y data). Ideally, 16 eddy current sensors would pass the same defects and output the same amplitude at the same location. However, since there may be a difference in sensitivity for each eddy current sensor, a process of correcting this is necessary.

The sensor calibration method according to the present disclosure further includes the step of removing noise of the reference data at all times after the receiving of the reference data (S10) (S11) and removing the tilt tendency of the reference signal from which the noise is removed (S12). can do.

11 is an exemplary diagram of a process of removing noise of reference data.

Referring to (a) of FIG. 11, it can be seen that noise (noise) is included in a signal output from any one eddy current sensor. FIG. 11B is a signal outputted by the Discrete Cosine Transform (DCT) method. The high frequency component is removed to obtain a signal from which noise is removed as shown in FIG.

12 is an exemplary diagram of a process of removing a tilt tendency of reference data.

Referring to FIG. 12A, a signal from which noise is removed may be confirmed in FIG. 11. As can be seen from (a) of FIG. 12, as the value of the X-axis (Sampling Number) increases, it can be seen that the signal tends toward the '-' direction. 12B is a result obtained by using the Bisquar & Gibens method of the polynominal fitting of the signal of FIG. In Figure 12 (b) it can be seen the trend toward the '-' direction of the signal and its magnitude. FIG. 12C is a result of removing a tendency toward the '-' direction of the signal.

Referring back to FIG. 8, in step S20, the phases of the plurality of eddy current sensor signals included in the reference data may be matched.

According to one embodiment of the present specification, the phase correction step S20 may be a step of correcting phases of a plurality of eddy current sensor signals with a predetermined reference phase value. The preset reference phase value may be variously set and preferably 45 degrees.

In operation S30, the amplitudes of the plurality of eddy current sensor signals included in the reference data may be matched.

According to one embodiment of the present specification, the amplitude correction step S30 sets a signal having the largest amplitude among a plurality of eddy current sensor signals as a reference amplitude value, and corrects the amplitudes of the remaining eddy current sensor signals to the reference amplitude value. It may be a step.

13 is a reference diagram of phase and amplitude correction.

FIG. 13A is an exemplary diagram of phase values to be corrected such that 16 eddy current sensors have a phase value of 45 degrees. FIG. 13B is an exemplary diagram of values to be set so that the signal having the largest amplitude among the 16 eddy current sensors is set as the reference amplitude value, and the remaining eddy current sensor signals have the same amplitude value. FIG. 13C shows data before phase and amplitude correction, and FIG. 13D shows data after phase and amplitude correction.

14 is an exemplary diagram in which the sensed data is matched with a color pattern after phase and amplitude correction.

Referring to FIG. 14, it corresponds to the defect of the sample rail illustrated in FIG. 9. This confirms that a plurality of sensor calibrations have been completed. The sensor calibration method according to the present specification is a method of calibrating using amplitude and phase by using a signal obtained by scanning one defect sample once, and has an advantage of shortening of time and easy operation compared to the conventional technology.

Hereinafter, a method of detecting a defect of a rail using a plurality of eddy current sensors (hereinafter, 'rail defect detection method') will be described. In describing the rail defect detection method according to the present specification, since the rail defect detection apparatus described above is used, repeated description of each configuration will be omitted.

Meanwhile, in order to perform the rail defect detection method according to the present disclosure, sample data derived from a standard defect test capable of estimating the size of a defect may be stored in advance. In the present specification, the 'standard defect test' means to test a sample rail in which defects having various preset lengths, widths, and depths are formed with a rail defect detecting apparatus according to the present specification. Data for defects of various lengths, widths, and depths measured through the standard defect test is 'sample data' herein. That is, the sample data is data that is compared or a reference in analyzing the size of the defect using the signal size of the defect measured by the eddy current sensor.

Analysis of defects can be divided into length, width and depth. The sensor calibration described above compensates for outputting the same value for the same defect between a plurality of eddy current sensors, and the magnitude of the defect cannot be estimated only by the output sensing value itself. Therefore, the measurement values for the defect samples having various lengths, widths, and depths are stored in advance, and the lengths, widths, and depths of the defects can be estimated by comparing the measured values of the defects detected in the actual inspection rail with the sample data. Can be.

15 is a flowchart illustrating a rail defect detection method according to an embodiment of the present specification.

Referring to FIG. 15, a rail defect detecting method according to an exemplary embodiment of the present specification may include receiving inspection data (S100), defect length estimation step (S110), defect depth estimation step (S120), and defect width estimation step (S130). It may include.

First, in step S100, the plurality of eddy current sensors may receive data passing through the inspection target rail (hereinafter referred to as inspection data).

Next, in step S110, the length of the defect may be estimated using the amplitude value of the inspection data.

According to one embodiment of the present specification, the defect length estimation step S110 may estimate the length of a defect through Equation 1 below.

<Equation 1>

Length (mm) = Ticks (b-a) * ODOmeter (mm)

Length (mm): estimated length of defect

a, b: the point where the slope of the amplitude signal is '0'

Ticks (b-a): distance between points with slope '0'

-ODOmeter (mm): Travel distance of sensor calculated through encoder data

16 is a reference diagram of a defect length estimation step according to the present specification.

Next, in step S120, the depth of the defect may be estimated using the phase value of the inspection data.

According to one embodiment of the present specification, the defect depth estimation step S120 may estimate the length of a defect through Equation 2 below.

<Equation 2>

Depth (mm) = a _One * PhaseAngle (deg) + a ₀

Depth (mm): estimated depth of defect

PhaseAngle (deg): Phase of eddy current sensor signal

a ₁ : slope value collected through standard defect test

a ₀ : intercept value collected through standard defect test

17 is a reference diagram of a defect depth estimation step according to the present specification.

Next, in operation S130, an area of a defect may be estimated using an eddy current sensor signal having an amplitude equal to or greater than a preset threshold value among the inspection data.

According to one embodiment of the present specification, the defect area estimating step (S130) may be a step of estimating the length of a defect through Equation 3 below when one eddy current sensor signal having an amplitude greater than or equal to the threshold is provided.

<Equation 3>

Width (mm) = (S _One  * R _m ) / (aD ²  + bD + c)

Width (mm): estimated width of defect

S ₁ : Diameter of the sensor

R _m : Magnetic force of the defect signal

-D: expected depth of defect

a, b, c: coefficient values collected through standard defect tests

18 is a reference diagram of a defect area estimation step when there is one eddy current sensor signal having an amplitude greater than or equal to a threshold according to an embodiment of the present specification.

According to another embodiment of the present disclosure, the defect area estimating step (S130) may be a step of estimating a length of a defect through Equation 4 below when two or more eddy current sensor signals having an amplitude greater than or equal to the threshold value are provided. .

<Equation 4>

Width (mm) = (N _Valid  * S _i ) + (N _Valid -1) * W _int  -(S _i  -W _BL )-(S _i  -W _BR )

W _BL  = (S _i  * R _BL ) / R _MAX

W _BR  = (S _i  * R _BR ) / R _MAX

Width (mm): estimated width of defect

-N _Valid : Number of eddy current sensors with amplitude above threshold

S _i : Diameter of the i th sensor

W _int : The distance between two eddy current sensors with an amplitude above the threshold

-R _MAX : Maximum value of magnetic peak

-R _BL : The peak value of magnetic force above the threshold among the sensors located on the left based on the maximum peak value of magnetic force

-R _BR : Magnetic force peak value over threshold among sensors located on the right side based on the maximum magnetic field peak value

19 is a reference diagram of a defect area estimating step when two or more eddy current sensor signals having an amplitude or more according to another embodiment of the present specification have an amplitude.

Meanwhile, the sensor calibration method and the rail defect detection method according to the present specification may be performed by a microprocessor. In this case, each step of the sensor calibration method and the rail defect detection method may be implemented by a program module operated by a microprocessor. The program module may be embodied in the form of program instructions that can be executed by computer means and recorded in a computer-readable medium.

The computer readable medium may include program instructions, data files, data structures, etc. alone or in combination. Program instructions recorded on the media may be those specially designed and constructed for the purposes of the present invention, or they may be of the kind well-known and available to those skilled in the computer program arts.

The computer readable recording medium includes a memory. Computer-readable recording media also include magnetic media such as hard disks, floppy disks, and magnetic tape, optical media such as CD-ROMs, DVDs, and magnetic disks, such as floppy disks. Hardware devices specially configured to store and execute program instructions such as magneto-optical media and ROM, RAM, flash memory and the like.

Examples of program instructions include not only machine code generated by a compiler, but also high-level language code that can be executed by a computer using an interpreter.

100: rail defect detection device
110: encoder
120: processor
130: communication module
140: frequency generator
150: Eddy current sensor

Claims (4)

A sensor calibration method of a rail defect detection device including a plurality of eddy current sensors,
A reference data receiving step of receiving, by the plurality of eddy current sensors, data passing through a defect formed in a sample rail (hereinafter referred to as 'reference data');
Removing noise of the reference data;
Removing the tilting tendency in the '-' direction of the noise-rejected reference signal;
A phase correction step of matching phases of a plurality of eddy current sensor signals included in the reference data; And
And an amplitude correction step of setting a signal having the largest amplitude among a plurality of eddy current sensor signals to a reference amplitude value and amplifying the amplitude of the remaining eddy current sensor signal to the reference amplitude value. delete delete delete

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