KR20240043003A - Method and apparatus for estimating generation position of signal using plurality of sensors - Google Patents

Abstract

The present invention relates to an apparatus and method for estimating a signal generation location using a plurality of sensors. The device is placed on different locations of the structure and includes a plurality of sensors that detect the signal; And it may include a processor connected to the plurality of sensors. The processor randomly sets an estimated position, calculates the distance between the set estimated position and each sensor, and based on the calculated distance and the speed of the signal, the time it takes for the signal to reach each sensor from the estimated position. Calculate the estimated arrival time, calculate the actual arrival time it took for the signal to reach each sensor, calculate the error between the estimated arrival time and the actual arrival time, and if the error is less than a specified value, determine the estimated location. The location of the signal is determined, and if the error exceeds the specified value, the estimated position is updated based on the error, and the position estimation procedure can be repeated based on the updated estimated position. The present invention can accurately estimate the location where a signal occurs (e.g., defect location) using multiple sensors. This invention was funded by the Ministry of Science and ICT, and is part of the 2022 5G-based Digital Twin Public Leading Project of the Korea Intelligence and Information Society Promotion Agency (Project name: Ulsan Digital Twin-based Industrial Complex Integrated Management Platform Construction Project, Project Period: April 15, 2022) ~ December 31, carried out with support from Agreement No.: 2022-Convergence-Wei05).

Description

Apparatus and method for estimating the location of signal generation using multiple sensors {METHOD AND APPARATUS FOR ESTIMATING GENERATION POSITION OF SIGNAL USING PLURALITY OF SENSORS}

The present invention relates to an apparatus and method for estimating the location of a signal using a plurality of sensors.

Recently, as society has become urbanized, industrialized, and specialized, the construction of various industrial facilities (e.g., water pipes, gas pipes, boilers, generators, etc.) continues. However, concerns about the safety of industrial facilities are also increasing. In particular, if a defect occurs in the internal structure of an industrial facility that is hidden rather than exposed to the outside, it cannot be easily observed, raising concerns about safety.

Therefore, there is a need for a method that can detect defects (e.g. deformation, cracks, etc.) in the internal structures of industrial facilities at an early stage and respond appropriately. Recently, non-destructive inspection, which allows inspection of defects without damaging the object, has been attracting attention. In particular, it has the advantage of not only providing high sensitivity and continuous inspection, but also being applicable even when access is restricted as it is not limited by the structure of the object or the size or direction of the defect, making it possible to perform non-destructive testing using Acoustic Emission (AE) signals. Testing methods are attracting attention. The non-destructive testing method using the acoustic emission signal determines whether a defect exists by using an elastic wave that is generated on its own and propagates along the inside of the object when a defect (e.g., deformation or crack) occurs in the object to be inspected.

However, the acoustic emission signal is difficult to interpret accurately because it is mixed with various noises ranging from low-frequency bands to high-frequency bands, and there are problems with low reliability and repeatability, such as results varying depending on the sensitivity of the sensor. Therefore, a non-destructive testing system using acoustic emission signals is required to accurately estimate the location of defects (e.g. cracks, deformation, etc.) in various structures.

The purpose of the present invention is to solve the above-described problems and to provide an apparatus and method that can accurately estimate the location where a signal occurs (e.g., the location where a defect occurs) using a plurality of sensors.

To achieve this purpose, an apparatus for estimating the location of a signal using a plurality of sensors according to an embodiment of the present invention includes a plurality of sensors disposed at different positions of a structure and detecting the signal; And it may include a processor connected to the plurality of sensors. The processor randomly sets an estimated position, calculates the distance between the set estimated position and each sensor, and based on the calculated distance and the speed of the signal, the time it takes for the signal to reach each sensor from the estimated position. Calculate the estimated arrival time, calculate the actual arrival time it took for the signal to reach each sensor, calculate the error between the estimated arrival time and the actual arrival time, and if the error is less than a specified value, determine the estimated location. The location of the signal is determined, and if the error exceeds the specified value, the estimated position is updated based on the error, and the position estimation procedure can be repeated based on the updated estimated position.

The processor may set the centers of the plurality of sensors as the estimated positions.

The processor may calculate the actual arrival time based on the difference in arrival times when the signal reached each of the plurality of sensors.

The processor may calculate the partial derivative of the error and update the estimated position by subtracting the partial derivative of the calculated error from the estimated position.

The processor may multiply the partial derivative of the error by a specified weight before subtracting the partial derivative of the calculated error from the estimated position.

A method of estimating the location of a signal using a plurality of sensors according to an embodiment of the present invention includes the steps of arbitrarily setting the estimated location; calculating the distance between the set estimated position and each sensor; calculating an estimated arrival time for the signal to reach each sensor from the estimated location, based on the calculated distance and the speed of the signal; calculating the actual arrival time it took for the signal to reach each sensor from the generation location; calculating an error between the estimated arrival time and the actual arrival time; If the error is less than or equal to a specified value, determining the estimated position as the generation position of the signal; and when the error exceeds the specified value, updating the estimated position based on the error and repeating the position estimation procedure based on the updated estimated position.

The step of arbitrarily setting the estimated position may include setting the centers of the plurality of sensors as the estimated position.

Calculating the actual arrival time may include relatively calculating the signal based on a difference in arrival times at each of the plurality of sensors.

Updating the estimated position may include calculating a partial derivative of the error; and subtracting the partial derivative of the calculated error from the estimated position.

Updating the estimated position may include multiplying the partial derivative of the error by a specified weight before subtracting the partial derivative of the calculated error from the estimated position.

Various embodiments of the present invention can accurately estimate (or express) the location where a signal occurs (e.g., the location where a defect occurs) using a plurality of sensors (e.g., three or more). Because of this, the present invention can initially prevent problems caused by defects in structures (e.g., pressure vessels, oil tanks, pipes, nuclear reactors, aircraft, concrete piers, etc.).

Figure 1 is a diagram for explaining the principle of estimating the location of a signal using a plurality of sensors according to an embodiment of the present invention.
Figure 2 is a flowchart illustrating a method of estimating the location of a signal using a plurality of sensors according to an embodiment of the present invention.
Figures 3A to 8B are exemplary diagrams to explain a method of estimating the location of a signal using a plurality of sensors according to an embodiment of the present invention.
Figure 9 is a block diagram of a device for estimating the location of signal generation using a plurality of sensors according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. The advantages and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and will be implemented in various different forms. The present embodiments only serve to ensure that the disclosure of the present invention is complete and that common knowledge in the technical field to which the present invention pertains is not limited. It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims. Hereinafter, like reference numerals refer to like components.

Although first, second, etc. are used to describe various elements, elements and/or sections, it is understood that these elements, elements and/or sections are not limited by these terms. These terms are merely used to distinguish one element, element, or section from other elements, elements, or sections. Therefore, it goes without saying that the first element, first element, or first section mentioned below may also be a second element, second element, or second section within the technical spirit of the present invention.

The terminology used herein is for describing embodiments and is not intended to limit the invention. As used herein, singular forms also include plural forms, unless specifically stated otherwise in the context. As used in the specification, “comprises” and/or “made of” refers to a referenced component, step, operation and/or element of one or more other components, steps, operations and/or elements. Does not exclude presence or addition.

Unless otherwise defined, all terms (including technical and scientific terms) used in this specification may be used with meanings that can be commonly understood by those skilled in the art to which the present invention pertains. Additionally, terms defined in commonly used dictionaries are not interpreted ideally or excessively unless clearly specifically defined.

Figure 1 is a diagram for explaining the principle of estimating the location of a signal using a plurality of sensors according to an embodiment of the present invention.

Referring to FIG. 1, the present invention can estimate (or determine) the signal generation location 10 using a plurality of sensors 101, 102, 103, 104, and 105. The signal generation location 10 refers to the location where a defect (e.g., deformation, crack, or destruction) occurs in a structure (e.g., pressure vessel, oil tank, pipe, nuclear reactor, aircraft, concrete pier, etc.). The plurality of sensors 101, 102, 103, 104, and 105 may be acoustic emission (AE) sensors that detect signals generated by defects (eg, elastic waves). A plurality of sensors 101, 102, 103, 104, and 105 may be attached to a structure (not shown) to be inspected for defects.

In the present invention, after attaching a plurality of sensors (101, 102, 103, 104, 105) to a structure, a signal (e.g., elastic wave) generated at the defect location (10) reaches each sensor from the defect location (10). The defect location 10 can be estimated based on the error between the actual arrival time taken and the estimated arrival time taken to reach each sensor from a randomly set estimated position. In detail, the estimated position is randomly set, the estimated position is continuously updated by reflecting the error until the error becomes less than a specified value, and when the error becomes less than the specified value, the updated estimated position is changed to the defect location (10 ) can be determined. A detailed description of this will be provided later with reference to FIGS. 2 to 8B.

Meanwhile, although five sensors 101, 102, 103, 104, and 105 are shown in FIG. 1, this is only an example, and the present invention can estimate the defect location using three or more sensors.

FIG. 2 is a flowchart illustrating a method of estimating the location of a signal using a plurality of sensors according to an embodiment of the present invention, and FIGS. 3A to 8B illustrate a plurality of sensors according to an embodiment of the present invention. This is an example diagram to explain a method of estimating the location of signal occurrence.

Referring to FIGS. 2 to 8B, the method for estimating the location of a signal using a plurality of sensors according to an embodiment of the present invention (hereinafter referred to as the location estimation method) includes arbitrarily setting the estimated location (S210). It can be included. In step S210, the center of a plurality of sensors installed in the structure can be set as the estimated position. For example, the estimated position Ps may be set to the center of six sensors (P ₁ , P ₂ , P ₃ , P ₄ , P ₅ , and P ₆ ), as shown in FIG. 3A . Meanwhile, in FIG. 3A, “source” means the signal generation location (defect location). Alternatively, step S210 may compare the signal strengths of the sensors (P ₁ , P ₂ , P ₃ , P ₄ , P ₅ , and P ₆ ) and arbitrarily set an estimated position around the sensor with a high signal strength.

The location estimation method may include calculating the distance between the estimated location and each sensor (S220). The distance between the estimated location and each sensor can be calculated using <Equation 1> below.

… … … <Equation 1>

In the above <Equation 1>, “d _i ” means the distance between the ith sensor and the estimated position (P _S ), “P _i ” means the location of the ith sensor, and “x _i ” means the ith sensor. It means the x-coordinate of the sensor, “x _s ” means the x-coordinate of the estimated position, “y _i ” means the y-coordinate of the ith sensor, and “y _s ” means the y-coordinate of the estimated position. . Here, the location (coordinates) of each sensor can be known when installing the sensor in the structure.

The location estimation method may include calculating the estimated arrival time it takes for the signal to reach each sensor from the estimated location (S230). The estimated arrival time can be calculated using <Equation 2> below.

… … … … <Equation 2>

In <Equation 2> above, “ " means the estimated arrival time of the ith sensor, and "v" means the propagation speed of the signal. Here, the propagation speed of the signal can be known through measurement. At this time, referring to Figure 3b, the estimated position is As it is set at the center of the sensors (P ₁ , P ₂ , P ₃ , P ₄ , P ₅ , P ₆ ), the estimated arrival time may be equal to “0.01”.

The location estimation method may include calculating the actual arrival time it takes for the signal to reach each sensor (S240). The actual arrival time can be relatively calculated based on the difference between the times it takes for the signal (eg, elastic wave) to reach each sensor (hereinafter referred to as signal arrival time). For example, the actual arrival time of the ith sensor may be the difference between the signal arrival time of the ith sensor and the signal arrival time of the reference sensor (e.g., the sensor with the smallest signal arrival time). Here, the signal arrival time can be measured based on a specified time (that is, the time when the sensors started measuring) because the actual time when the signal occurred is unknown.

The location estimation method may include calculating an error between the estimated arrival time and the actual arrival time (S250). The error can be calculated by <Equation 3> below.

.......... <Equation 3>

In <Equation 3> above, “ " means the actual arrival time of the ith sensor, that is, the error may be the sum of the squares of the difference between the actual arrival time and the estimated arrival time of each sensor.

The position estimation method may include a step (S260) of checking whether the error is less than (or less than) a specified value. As a result of checking in step S260, if the error is not less than a specified value, the position estimation method may include a step of updating the estimated position based on the partial derivative of the error (S270). Here, the partial derivative of the error ( ) is calculated by <Equation 4> below, and the updated estimated location ( ) can be calculated by <Equation 5> below. That is, the updated estimated location ( ) is the estimated location ( ), the partial derivative of the error ( ) to speed( ) may be the value obtained by subtracting the multiplied value.

… … … <Equation 4>

… … … … … <Equation 5>

In <Equation 5> above, “ "is a partial derivative ( ), which means the degree to which the partial differential value of the error is reflected in the estimated position. in other words, " If " is less than 1, the partial differential value may be reduced and reflected in the estimated position, and if it is greater than 1, the partial differential value may be enlarged and reflected in the estimated position. Meanwhile, in <Equation 5> above, " " is omitted (i.e. " "= 1) can be.

After updating the estimated position, the position estimation method returns to step S220 and may repeatedly perform error-based estimated position updating until the error becomes less than a specified value. As the number of estimated location updates based on the error increases, the actual location can be accurately estimated. For example, as shown in FIGS. 4A to 7B, as the number of updates increases, the estimated position P _S gradually moves toward the source, and the interval between the estimated arrival time and the actual arrival time increases. A decrease can be seen.

On the other hand, when the error is less than a specified value, the position estimation method may include a step (S280) of determining the estimated position as the signal generation position (defect position). As shown in FIGS. 8A and 8B, if the estimated position is updated 100 times, the error may become less than a specified value. That is, as shown in Figure 8a, the estimated position (P _S ) is close to the source position (source), and as shown in Figure 8b, the sensors (P ₁ , P ₂ , P ₃ , P ₄ , P ₅ , P ₆ ), it can be seen that the estimated arrival time and actual arrival time are almost the same. Therefore, the present invention can determine the estimated position as the actual signal generation position.

Figure 9 is a block diagram of an apparatus for estimating the location of a signal using a plurality of sensors according to an embodiment of the present invention.

Referring to FIG. 9, a device 900 for estimating the location of a signal using a plurality of sensors according to an embodiment of the present invention (hereinafter referred to as a location estimation device) includes a memory 910, a display 920, and a processor. It may include (930), a sensor module (940), and a communication module (950).

The memory 910 may be electrically connected to the processor 930 and may store various programs for operating the position estimation device 900 and various commands and/or instructions for operating the processor 930. The memory 910 may include at least one of internal memory or external memory. Internal memory can be volatile memory (such as DRAM, SRAM, or SDRAM), non-volatile memory (such as one time programmable ROM (OTPROM), PROM, EPROM, EEPROM, mask ROM, flash ROM, flash memory, hard drive, or It may include at least one of a solid state drive (SSD). The external memory may be SD (secure digital), Micro-SD, Mini-SD, or USB (universal) that can be connected to the location estimation device 900 through various interfaces. serial bus) memory, etc. The memory 910 may store a position estimation module 911, which is a software program that performs the above-described position estimation method.

Display 920 may provide input functionality and/or output functionality. For example, the display 920 may include a touch panel and/or a display panel. Display 920 may display the estimated location.

The processor 930 may receive commands or instructions from the memory 910 and control each component according to the received commands or instructions to perform various functions. The processor 930 may be formed of a central processing unit (CPU), a micro control unit (MCU), a micro processor unit (MPU), or the like. The processor 930 according to an embodiment of the present invention can control a procedure for estimating the signal generation location using the position estimation module 911. A detailed description of this will be omitted as it has been described with reference to FIGS. 2 to 8B.

The sensor module 940 may include multiple sensors (eg, three or more). For example, the sensor module 940 may detect a signal (eg, elastic wave) generated at a defect location in the structure.

The communication module 950 may communicate with an external device (eg, a server that manages the structure). The communication module 950 may transmit the signal generation location determined by location estimation to an external device.

As described above, the present invention is described with reference to the illustrated embodiments, but these are merely illustrative examples, and those of ordinary skill in the art to which the present invention pertains can make various modifications without departing from the gist and scope of the present invention. It will be apparent that variations, modifications, and equivalent other embodiments are possible. Therefore, the true scope of technical protection of the present invention should be determined by the technical spirit of the attached claims.

900: Location estimation device
910: Memory 920: Display
930: Processor 940: Sensor module
950: Communication module

Claims (10)

In a device that estimates the location of a signal using a plurality of sensors,
A plurality of sensors placed on different locations of the structure and detecting the signals; and
Including a processor connected to the plurality of sensors,
The processor is
Set the estimated location randomly,
Calculate the distance between the set estimated position and each sensor,
Based on the calculated distance and the speed of the signal, calculate an estimated arrival time for the signal to reach each sensor from the estimated location,
Calculate the actual arrival time it took for the signal to reach each sensor,
Calculate the error between the estimated arrival time and the actual arrival time,
If the error is less than or equal to a specified value, determine the estimated position as the occurrence position of the signal, and
If the error exceeds the specified value, the device updates the estimated position based on the error and repeats the position estimation procedure based on the updated estimated position.
According to claim 1,
The processor is
A device characterized in that the centers of the plurality of sensors are set to the estimated positions.
According to claim 1,
The processor is
A device characterized in that the actual arrival time is calculated based on the difference in arrival times when the signal reaches each of the plurality of sensors.
According to claim 1,
The processor is
An apparatus for calculating the partial derivative of the error and updating the estimated position by subtracting the partial derivative of the calculated error from the estimated position.
According to claim 4,
The processor is
A device characterized in that the partial derivative of the error is multiplied by a specified weight before subtracting the partial derivative of the calculated error from the estimated position.
In a method of estimating the location of a signal using a plurality of sensors,
Randomly setting an estimated location;
calculating the distance between the set estimated position and each sensor;
calculating an estimated arrival time for the signal to reach each sensor from the estimated location, based on the calculated distance and the speed of the signal;
calculating the actual arrival time it took for the signal to reach each sensor from the generation location;
calculating an error between the estimated arrival time and the actual arrival time;
If the error is less than or equal to a specified value, determining the estimated position as the generation position of the signal; and
If the error exceeds the specified value, updating the estimated position based on the error and repeating the position estimation procedure based on the updated estimated position.
According to claim 6,
The step of arbitrarily setting the estimated position is
A method comprising setting the centers of the plurality of sensors to the estimated positions.
According to claim 6,
The step of calculating the actual arrival time is
A method comprising relatively calculating the signal based on the difference in arrival times at each of the plurality of sensors.
According to claim 6,
The step of updating the estimated location is
calculating the partial derivative of the error; and
and subtracting the partial derivative of the calculated error from the estimated position.
According to clause 9,
The step of updating the estimated location is
and multiplying the partial derivative of the error by a specified weight before subtracting the partial derivative of the calculated error from the estimated position.

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