JPS5823895B2 - Vibration source position detection method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vibration source position detection method and apparatus for accurately detecting the position of a vibration source generated in a detected object.

In recent years, various devices using advanced technology, such as nuclear power generation devices, have been developed.

However, safety measures are the most important issue for such devices, and current emphasis is placed on early detection of failures.

For example, in a nuclear power plant, if a crack occurs in the cooling piping, radioactive materials inside the reactor will leak out of the reactor through this crack, which is extremely dangerous.

Therefore, if the position of a crack can be accurately detected at the same time as it occurs, prompt measures can be taken, thereby preventing accidents.

In this case, it is known that when cracks, cracks, etc. occur in an object, ultrasonic vibrations are generated using that part as a vibration source.

Therefore, in order to detect the occurrence point and position of the above-mentioned cracks, cracks, etc., it is necessary to detect this vibration and at least
It is obtained by detecting and calculating the vibration propagation time difference at a point.

However, as mentioned above, the vibration detection sensor is simply
In the conventional method of detecting the vibration source from the detection difference of the vibrations by arranging the vibration sources separately, it was not possible to perform reliable detection over a wide range of areas.

In other words, if three vibration detection sensors are arranged to surround a wide area, the distance between each vibration detection sensor will become extremely long, and the vibration attenuation will increase accordingly, making it impossible to perform reliable vibration detection. .

However, when the vibration attenuation increases in this way, it becomes impossible to separate external noise signals from other parts outside the detection range and signals within the detection range, resulting in malfunctions. are doing.

Furthermore, in the above-mentioned detection method, since three detection positions are specified, it is extremely difficult to increase or decrease the detection range, and in particular, when expanding the detection range, detection accuracy must be sacrificed to some extent. It has its drawbacks.

Therefore, an object of the present invention is to provide a vibration source position detection method and apparatus that can perform highly accurate detection over a wide range.

Another object of the present invention is to provide a method and apparatus for detecting a vibration source position in which the detection range can be easily increased or decreased.

Still another object of the present invention is to provide a vibration source position detection method and apparatus that prevent malfunctions due to external noise vibrations.

In order to achieve such an object, the vibration source position detection method and device according to the present invention include four or more vibration detection sensors distributed in a mesh-like manner in a detection range, and the first vibration Based on the output of the detected vibration detection sensor, the vibration detection sensors located around this vibration detection sensor are selected as a first vibration detection sensor group, and then the vibration detection sensors in the first vibration detection sensor group are selected. The vibration detection sensors located around the vibration detection sensor and included in the first vibration detection sensor group are selected as a second vibration detection sensor group, and the vibration detection sensors in the second vibration detection sensor group are selected. A vibration detection sensor located around this vibration detection sensor and a second vibration detection sensor at the output.
Three vibration detection sensors are selected by selecting vibration detection sensors included in a group of vibration detection sensors, and these three vibration detection sensors are selected.
The vibration detection time difference of the three vibration detection sensors is calculated to detect the vibration source position within the triangular range connecting the three vibration detection sensors.

Still, the vibration source position detection device according to the present invention includes a first memory that stores only the signal that arrives first and sends out the corresponding output, and a vibration source that sends out the first signal in response to the output of the first memory. a first decoder that specifies a vibration detection sensor located around the detection sensor; a first gate that allows only the output of the vibration detection sensor corresponding to the output of the first decoder to pass; and a vibration detection sensor that has passed through the first gate. Specify a second memory that stores only the earliest output signal among the outputs and sends out the corresponding output, and a vibration detection sensor located around the vibration detection sensor corresponding to the output of the second memory. A second decoder, a second gate that allows only the output of the vibration detection sensor corresponding to the output of the second decoder to pass through, and a signal that is outputted earliest among the outputs of the vibration detection sensor that has passed through the second gate. The device includes a third memory that stores and holds a corresponding output and sends out a corresponding output, and a calculation unit that calculates the position of the vibration source based on the difference in output generation time of the first to third memories.

EMBODIMENT OF THE INVENTION Hereinafter, the vibration source position detection method and its apparatus according to the present invention will be explained in detail using the drawings.

FIG. 1 explains the basic principle of the vibration source position detection method and device according to the present invention. In the following explanation, in order to make the explanation easier, each vibration detection sensor is an equilateral triangle with the same dimensions. It is assumed that they are distributed and arranged so that they are located at each vertex of.

Therefore, this state is illustrated in FIG. 1.

In FIG. 1, reference numerals 1a to 1e indicate vibration detection sensors arranged at each vertex of the equilateral triangle that divides the detection range.

In the vibration detection range in which the plurality of vibration detection sensors 1a to 1e are distributed in this way, a crack occurs, for example, at point 2 within the range surrounded by the vibration detection sensors 1a, 1b, and lc. As described above, ultrasonic vibrations are generated from this part, and these ultrasonic vibrations propagate concentrically with point 2 as the center.

In this case, since the vibration detection sensor 1a is located closest to point 2, which is the vibration source, the detection signal is first sent out from the vibration detection sensor 1a.

Next, using the output of this vibration detection sensor 1a, the vibration detection sensors 1b to 1g located around it are selected and selected as a first vibration detection sensor group, and signals from other vibration detection sensors are blocked.

Therefore, by reducing the detection range in this way, the first
Malfunctions due to external noise from outside the range surrounded by the group of vibration detection sensors are reduced.

Next, a vibration detection sensor IC located second closest to point 2, which is the vibration source, detects the vibration propagated from point 2 and generates an output.

In this way, when the vibration detection sensor 1c in the first group of vibration detection sensors generates an output, this output signal is used to locate the surrounding area and the above.

Vibration detection sensor 1 included in the first vibration detection sensor group
Select b and 1d to block signals from other vibration detection sensors.

Therefore, it goes without saying that by further reducing the vibration detection range in this manner, malfunctions due to external noise are further reduced.

Next, the vibration detection sensor 1c located at the third nearest point with respect to point 2, which is the vibration source, generates an output, and this output signal causes the vibration detection sensor 1c located around it and included in the second group of vibration detection sensors to generate an output. Vibration detection sensor 1b is selected.

In this way, by sequentially determining the AND conditions for that sensor and the sensors located around it based on the output of each vibration detection sensor that detected the first to third vibrations, the selection of the corresponding sensor is reduced. , 3 by 3 operations
vibration detection sensors 1a, 1b, and 1c.

Therefore, the vibration source is located within the triangular range connecting the remaining three vibration detection sensors 1a, 1b, and 1c.

Therefore, the output time difference of the vibration detection sensors 1a, lb, and lc that detected the vibrations from the first to third vibrations, that is, the vibration detection/output sensors 1a, lb, and lc left by the third selection operation, is calculated, and this time difference and each vibration detection sensor are calculated. Sensor 1 a, Ib, I
By calculating using the distance between the points c, it is possible to accurately determine the point 2 as a vibration source included in the range connecting the vibration detection sensors 1a, 1b, and 1c.

Therefore, if such a detection method is used, even if a large number of vibration detection sensors are installed in order to perform detection while gradually reducing the detection range, external noise will increase in proportion to the number of vibration detection sensors. This prevents the vibration detection sensor from malfunctioning, allowing stable measurements.

Furthermore, since the vibration detection sensors can be arranged relatively densely, the vibrations can be detected in a state where the vibrations are less attenuated, and thus the noise signal and the vibration detection signal can be reliably separated.

Further, the detection range can be easily increased or decreased by placing or removing the vibration detection sensor at the vertex of the triangular minute detection range, and the operation is extremely easy.

FIG. 2 is a block diagram showing an embodiment of the vibration source position detection method according to the present invention, in which vibration detection sensors 1a to 1■ are arranged as shown in FIG.
3a to 31 are preamplifiers that amplify the outputs of the vibration detection sensors 1a to 11 in the vicinity of the vibration detection sensors 1a to 11, and 3a to 31 input the output signals of the preamplifiers 2a to 21 to form envelope waveforms, and only for periods exceeding a predetermined threshold value. A waveform shaping circuit 3 inputs the output signals of the respective waveform shaping circuits 3a to 31 through input terminals 4a to 41 and detects the first to third arrival order of the signals and the sensor number thereof. This is the arrival order determination unit.

The arrival order determining unit 3 is configured as follows.

In other words, the signals from input terminals 4a to 41 are input in parallel, only the signal that arrives first is stored, and the signal continues to be sent to the corresponding output terminal, while all signals subsequently supplied to other input terminals are blocked. A first memory 5a that converts the output of the first memory 5a into a binary code, a first code converter 6a that converts the output of the first memory 5a into a binary code, and a vibration detection sensor located around the vibration detection sensor corresponding to the output of the first code converter 6a. The first decoder to do? a, only the signals of the input terminals 4a to 41 specified by the first decoder 7a are sent to the second memo IJ.
5b, the first gate circuit 8a and the second memory IJ
a second code converter 6b for converting the output of the second code converter 6b into a binary code; a second decoder 7b for specifying a vibration detection sensor located around the vibration detection sensor corresponding to the output of the second code converter 6b; A second circuit supplies only the signals of input terminals 4a to 41 designated by the second decoder 7b from among the outputs of the gate circuit 8a to the third memory 5c.
It is comprised of a gate circuit 8b and a third code converter 6c that converts the output of the 37th memory 5C into a binary code.

The first to third memories 5a to 5c are configured to each send a storage completion signal after storing the arrival order.

FIG. 3 shows a specific embodiment of the first to third memories 5a to 5c, in which D-type flip-flop circuits 9 are set corresponding to the input terminals 4a to 41, respectively.
a to 91, and inverters 11a to invert the outputs of the flip-flops 9a to 910 and supply them to the output terminal 101.
111, and an inverter 13a that inverts the set outputs of the flip-flops 9a to 91 and supplies it to the AND gate 12.
~131, and flip-flops 9a-9 from each input terminal 4a-41 with the output of AND gate 12 as one input.
Ant-game that cuts off the signal supplied to the set input of 1.
N4a to 141, and when any of the seven lip-flops 9a to 91 is set by the earliest supplied signal, the set output is supplied to the corresponding output terminal, and each The flip-flops 9a to 91 determine the order of arrival by cutting off all subsequent input signals.

In this case, a storage completion signal is obtained by taking out the set output of each flip-flop 9a to 91 as a wired OR to the terminal 15, and by supplying a signal to the terminal 16 when the data continuation of the computer is completed, which will be described later. The memories 5a to 5c are being reset.

Further, in FIG. 2, reference numeral 17 denotes a first counter, which starts counting the clock pulses supplied to the terminal 18 by the storage completion signal from the first memory 5a, and by the storage completion signal from the second memory 5b. A first counter 19 stops counting, and a second counter 19 starts counting when the storage completion signal from the first memory 5a is received and stops counting when the storage completion signal from the third memory 5c is received. 1γ and 19 measure the time difference between the first signal and the second and third signals.

20 is a computer, and includes first to third code converters 6a to 6a.
The data supplied from the first to third vibration detection sensors 1a to 11 are inputted by inputting the data supplied from the first to third vibration detection sensors 1a to 11, and the time difference signals supplied from the first and second counters 17 and 19 are used. The position of the vibration source is calculated and the result is supplied to a terminal such as a cathode ray tube display device, an X-Y decoder, and a printer (not shown).

In the device configured in this way, if a crack occurs at point 2 as explained in FIG.
The ultrasonic vibrations generated from the center propagate concentrically.

First, the vibration detection sensor provided closest to point 2 is activated; in this case, vibration detection sensor 1a is activated and generates a signal.

This signal is amplified to a predetermined level via the preamplifier 2a and then supplied to the waveform shaping circuit 3a, where the waveform is shaped as described above and a pulse-like output is sent to the input of the arrival ranking judgment screen/path 3. Supplied to terminal 4a.

The signal supplied to the input terminal 4a is supplied only to the memory 5a because the first and second gate circuits 8a are all in a cut-off state, and only the first signal is recorded as explained in FIG. A signal is sent out only to the output terminal 1 corresponding to the input terminal 4a.

When the storage operation of the first memo 'J5a is completed, a storage completion signal is supplied to the start terminals of the first and second counters 17 and 19, thereby causing the first and second counters 1γ, 1
9 starts counting the clock signal supplied to terminal 18.

On the other hand, when a signal is sent from the first memo 'J5a, the code converter 6a is activated to send out a binary code signal corresponding to the number of the corresponding vibration detection sensor, in this case the vibration detection sensor 1a.

In other words, the vibration detection sensors 1a to 11 are a. If numbers 1 to 12 are assigned in the order of b and c, in this case a 4-bit signal tOspaOspa0pen1n will be sent out.

Therefore, the output signal of the first code converter 6a is the number of the vibration detection sensor that detected the vibration first, in the form of a binary code.

The output of the first code converter 6a is supplied to the computer 20 and also to the first decoder 7a, where the output is placed around the vibration detection sensor 1a specified by the first code converter 6a. Only the vibration detection sensors 1b to 1g that are detected are selected and designated by a diode matrix or the like in a bird-like manner.

This designation signal is supplied to the first gate circuit 8a, and the vibration detection sensors 1b to 1b designated by the first decoder 7a
Only the gate portion corresponding to 1g is opened, and all other portions remain blocked.

In this state, when the vibration detection sensor 1c located second closest to the vibration source point 2 detects vibration, this signal is supplied to the input terminal 4c via the preamplifier 2c1 and the waveform shaping circuit 3c.

In this case, the first gate 8a is activated by the vibration detection sensors 1a to 1g in accordance with the specified signal from the first decoder 7a, as described above.
Since only the portions corresponding to the input terminals 4a to 4g to which are connected are in an open state, the second detection signal supplied to the input terminal 4c passes through the first gate circuit 8a to the second memory I.
J 5 b.

Note that, as described above, the first memory 5a blocks all input signals after storing the first signal, and the second gate circuit 8b is all in a cut-off state.
The second detection signal is not supplied to any part other than the second memory 5b.

In this way, input terminal 4C to the second memo 'J 5 b
When the second detection signal supplied to the first counter 17 is supplied, this signal is stored as described above, and the signal is sent only to the corresponding output terminal, and the storage completion signal stops the count of the first counter 17. A terminal is supplied to stop the counting operation, and the time difference between the first detection signal and the second detection signal is determined.

On the other hand, the output of the memo IJ 5b is sent to the second code converter 6b.
The number of the vibration detection sensor 1c that sent out the second signal, that is, "3", is converted into a binary code signal ttOjJt.
It is supplied to the computer 20 as t Opp at 1pp tt 1pp.

Therefore, this second code converter 6b specifies the number of the vibration detection sensor that detected the vibration second.

On the other hand, the output of this second code converter 6b is supplied to a second decoder 7b, where the vibration detection sensors 1a, 1b located around the vibration detection sensor 1c designated by the second code converter 6b, 1j, 1, 11, 1
d is designated in a bird-like manner by a diode matrix or the like, and the designated output signal is supplied to the second gate circuit 8b.

The second gate circuit 8b opens only the input line portion designated by the second decoder 7b, and continues to cut off the other portions.

However, since the first gate circuit 8a is provided on the input side of the second gate circuit 8b, and only the input line portion specified by the first decoder 1a is in an open state, the third memory 5c is 1st. Second gate circuit 8a, s
A state is reached in which a signal can be input only to the ANDed portion of b.

Therefore, the third memory 5c is the vibration detection sensor 1b, 1d.
It is in a state where it can only accept signals.

Next, when the vibration detection sensor 1b located third closest to the vibration source point 1b detects vibration, this detection signal is supplied to the input terminal 4b via the preamplifier 2b and the waveform shaping circuit 3b. .

The signal supplied to the input terminal 4b is supplied to the third memory 5C via the first and second gate circuits 8a and 8b, in which only part of the human power line is open, as described above.

The third memo J5c stores the input signal and continues to send the signal only to the corresponding output terminal as in the case described above, and also supplies a storage completion signal to the count stop terminal of the second counter 19. , and supplies a time difference signal between the first detection signal and the third detection signal to the computer 20.

On the other hand, the output of the third memory 5c is supplied to the third code converter 6c, where the number of the vibration detection sensor 1b that detected the vibration third is converted into a binary code ttO
It is converted into pp tt Opp tt and pp tt On and supplied to the computer 20 .

When the series of operations is completed in this way, the computer 20 converts the output signals of the first to third code converters 6a to 6c and the first to third code converters 6a to 6c.
The count value of the second counter 17.19 is successively calculated, and thereby the three vibration detection sensors 1a, lb,
The position of point 2 as a vibration source included in the range connected by lc is calculated, and the result is displayed on a terminal (not shown).

In the above-mentioned embodiment, only the case where each vibration detection □ sensor is arranged at the apex of an equilateral triangle has been described, but the present invention is not limited to this, and may be arranged in various shapes. It goes without saying that the same effect can be obtained by placing the sensors at the vertices of the triangle, but in short, it is sufficient if they are placed in a mesh-like pattern.

Furthermore, in the above-mentioned embodiments, only the occurrence of cracks and cracks was explained, but the present invention is not limited thereto, and can be applied to detecting the location of occurrence of vibrations such as shocks and earthquakes. be.

As explained above, according to the vibration source position detection method and device according to the present invention, the vibration detection sensors are arranged in a mesh pattern, and the output signal of the vibration detection sensor that detects the vibration in the first to third positions is used. Since three vibration detection sensors located around the vibration source are selected by sequentially limiting the surrounding vibration detection sensors while obtaining an AND condition, malfunctions may occur when the number of vibration detection sensors is increased. can significantly reduce the occurrence of

In addition, in order to prevent malfunctions and allow multiple vibration detection sensors to be placed, the distance between each vibration detection sensor can be shortened, and as a result, vibration can be detected with less attenuation. The detection signal becomes larger, and it becomes extremely easy to separate the detection signal from external noise.

Furthermore, in the present invention, since the vibration detection sensors are arranged so that the detection range is formed by combining triangular minute detection ranges, increasing or decreasing the detection range requires changing the number of sensors. It has various excellent effects, such as making the operation extremely easy.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the arrangement of vibration detection sensors used to explain the basic principle of the vibration source position detection method and device according to the present invention, and FIG. 2 is the vibration source position detection method and device according to the present invention. A block diagram showing an embodiment of
FIG. 3 is a circuit diagram showing an example of the first to third memories shown in FIG. 2. 1a-11... Vibration detection sensor, 2...
...Points, 2a-21...Preamplifier, 3...
... Arrival order detection section, 3a to 31... Waveform shaping circuit, 4a to 41... Input terminal, 5a, 5c...
...first to third memory, 6a; to 6c...first to third code converter, 7a, 7b...first,
Second decoder, 8a, 8b...--First, second gate, 9a-91...Song flip-flop, 10a-10
1-output terminal, 11a to 111y13a...131.
...Inverter, 12.14a to 141...
...and gate, 17, 19... 1st゜2nd
Counter, 20... Calculator.

Claims (1)

[Claims] 1. Four or more vibration detection sensors are distributed and arranged in a net shape in a detection range for detecting the position of a vibration source, and the output of the first vibration detection sensor that detects vibration first is used to select only the surrounding vibration detection sensors to form a first vibration detection sensor group, and the output of the second vibration detection sensor included in the first vibration detection sensor group and which detected vibration second. A vibration detection sensor included in the first vibration detection sensor group and around the first vibration detection sensor group is selected as a second vibration detection sensor group, and a third vibration detection sensor included in the second vibration detection sensor group is selected.
Using the output of the third vibration detection sensor that detected the vibration first, select the vibration detection sensors around the third vibration detection sensor that are included in the second vibration detection sensor group, and select the vibration detection sensor that detected the third vibration. A method for detecting a position of a vibration source, characterized in that the position of the vibration source is detected based on the difference in vibration detection time between first to third vibration detection sensors. 2. The vibration source position detection method according to claim 1, wherein each vibration detection sensor is arranged at each vertex of an equilateral triangle. 3. The vibration source position detection method according to claim 1, wherein each vibration detection sensor is arranged at each vertex of a triangle, and the triangles are congruent. 4. A first memory that stores only the output of the first vibration detection sensor among the many vibration detection sensors arranged in a mesh pattern and sends out the corresponding output; a first decoder that specifies a vibration detection sensor located around the vibration detection sensor that sent out the first signal; a first gate that allows only the output of the vibration detection sensor corresponding to the output of the first decoder to pass through; a second memory that stores only the earliest output signal among the outputs of the vibration detection sensor that has passed through the gate and sends out the corresponding output; A second decoder that specifies a vibration detection sensor included in a group of vibration detection sensors specified by the first decoder, a second gate that allows only the vibration detection sensor output corresponding to the output of the second decoder to pass through, and a second gate. Among the outputs of the vibration detection sensor, a third memory stores and holds only the earliest output signal and sends out the corresponding output, and the vibration source is detected based on the difference in output generation time between the first and third memories. A vibration source position detection device including a calculation unit that calculates a position.