JPH1020017A - Displacement measuring system and displacement measuring device using ultrasonic wave - Google Patents

Abstract

(57) [Summary] (Modified) [Problem] To prevent minute disasters such as falling rocks and landslides, use ultrasonic technology to measure minute displacements of rocks and other monitored objects. It always keeps high-precision observations without being affected by weather conditions such as humidity, atmospheric pressure, wind, rainfall, snowfall, and fog. SOLUTION: Two or more small ultrasonic receivers 3 and 4 are installed on an object to be monitored, for example, a rock 1, and ultrasonic waves are transmitted from an ultrasonic transmitter 2 placed at a point separated by a certain distance. . At this time, the phase difference between the transmission signal and the reception signal is detected, and the phase difference between the respective ultrasonic receivers is compared based on the detected phase difference between the transmission signal and the reception signal, and the minute difference of the monitored object is determined. The influence of the weather condition is canceled by detecting the inclination and the displacement amount, and comparing the phase difference between the ultrasonic receivers based on the phase difference with the detected transmission signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a displacement measuring device for measuring a structure such as a rock, a bedrock or a pier by using ultrasonic waves.

[0002]

2. Description of the Related Art As a technique for measuring a minute movement of an object to be monitored such as a falling rock or a protective wall for predicting a disaster and giving an advance warning, there is a distance measuring apparatus using a laser technique. In this technology, a reflector that reflects the laser is installed on the object to be monitored, the laser is emitted from the measurement point toward this reflector, the reflected laser light is received, and the distance is measured by the time difference from the emitted laser. This enables extremely high-precision measurement. However, this device has disadvantages such as high price and susceptibility to weather such as rainfall and fog.

Aerial ultrasonic technology is used as another measuring device. This measurement method transmits ultrasonic waves toward the object, receives the reflected sound from the monitored object,
The time difference between transmission and reception is measured, and the distance is measured therefrom. Ultrasonic waves are easily affected by weather conditions in the air, and require a means of sound velocity correction by measuring weather conditions. Further, when the surface of the monitored object is not flat, the measurement accuracy is deteriorated due to the scattering of the reflected sound.

As described above, in general, a time difference and a phase difference in transmission and reception are measured, and a distance measurement, a minute displacement measurement, and the like are performed. However, the conventional technology is easily affected by weather conditions. Observation of three-dimensional displacement is difficult to realize.

[0005]

SUMMARY OF THE INVENTION Utilizing ultrasonic technology,
When measuring minute displacement of the monitored object, temperature, humidity,
Weather conditions such as air pressure, wind, rainfall, snowfall, and fog affect the propagation of ultrasonic waves. In order to maintain high-precision observation at all times without being affected by these conditions, it is necessary to provide a means for correcting a sound speed or the like by measuring weather conditions. Further, since the actual displacement of the monitored object is three-dimensional and very small, it is necessary to constantly detect these movements with high accuracy.

The present invention relates to a technique for solving these problems, and provides an all-weather type measurement which is hardly affected by weather conditions and a means for measuring a three-dimensional minute displacement of an object to be monitored. It is an object.

[0007]

[MEANS FOR SOLVING THE PROBLEMS] To achieve the object,
In the present invention, as described in the previous invention (Japanese Patent Application No. 8-49172),
Instead of detecting the phase difference between the transmitted signal and the received signal and measuring the displacement of the monitored object from the relationship between the phase difference and the sound speed, the monitored object is obtained by taking the difference between the phase differences of a plurality of received signals. A displacement measurement method for observing three-dimensional minute displacement of an object is proposed. According to this method, since the difference in sound speed in the sound wave propagation path until the ultrasonic wave transmitted from the ultrasonic transmitter is received by the plurality of ultrasonic receivers can be canceled, the system is less affected by weather conditions.

According to the first and second aspects, two or more ultrasonic receivers installed on an object to be monitored and one ultrasonic transmitter installed at a stable place separated by a predetermined distance, The phase difference between the transmission signal of the ultrasonic transmitter and the reception signal of the ultrasonic receiver is detected, the difference between the phase differences between the ultrasonic receivers is obtained, and the displacement and the inclination are detected. Or, one ultrasonic transmitter installed on the monitored object,
In two ultrasonic receivers installed at a stable place separated by a certain distance, the difference between the phase differences between the respective ultrasonic receivers is obtained by the same principle, and the displacement and the inclination are detected.

According to a third aspect of the present invention, there are provided two or more ultrasonic receivers installed on an object to be monitored and one or more ultrasonic transmitters installed on a stable place separated by a predetermined distance. Find the difference of the phase difference between each ultrasonic receiver of
Detect the displacement and tilt. Alternatively, in one or more ultrasonic transmitters installed on the monitored object and two ultrasonic receivers installed in a stable place separated by a fixed distance, each ultrasonic wave is transmitted according to the same principle. The difference between the phase differences between the receivers is obtained, and the displacement and the inclination are detected.

According to a fourth aspect of the present invention, the ultrasonic waves are caused to interfere by two or more ultrasonic transmitters installed on the monitored object, and the interference waves are installed at a stable place separated by a predetermined distance.
More than one ultrasonic receiver detects the displacement direction or displacement amount of the monitored object.

According to the fifth aspect, one or more ultrasonic receivers installed on the monitored object and two or more ultrasonic transmitters installed on a stable place separated by a certain distance,
The interference wave is detected based on the same principle as in claim 4, and the displacement direction or the displacement amount of the monitored object is detected.

According to a sixth aspect of the present invention, in the means for interfering with the ultrasonic wave, means for arbitrarily changing the phase of the transmission signal of one or more ultrasonic transmitters is provided, and a predetermined detection threshold value or sometimes a detection threshold value is set. The recording signal recorded in the moment is compared with the amplitude value or the arbitrarily changed phase value of the detected interference wave of the ultrasonic wave, and the displacement direction or the displacement amount of the monitored object is detected.

According to a seventh aspect of the present invention, the displacement amount and the inclination of the monitored object are detected from the phase difference, the amplitude value or the arbitrarily changed phase value obtained by the above means.

According to an eighth aspect of the present invention, the arrangement of the plurality of ultrasonic receivers or ultrasonic transmitters with respect to the object to be monitored is changed to measure the minute displacement of the object to be monitored in three dimensions with high accuracy.

According to the ninth aspect, the displacement and the inclination are detected, output, recorded, or displayed based on the phase difference between the ultrasonic receivers obtained by the above-described means.

According to a tenth aspect of the present invention, the displacement and inclination of the object to be monitored are detected or output from the amplitude value of the ultrasonic interference wave obtained by the above means or the phase value arbitrarily changed. Or record or display.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a concrete example of a falling rock monitoring system as a specific embodiment. This system includes, for example, ultrasonic receivers 3 and 4 on a rock 1 to be monitored.
Is fixedly installed, and the ultrasonic transmitter 2 is installed on a stable ground separated by a certain distance. The ultrasonic signal transmitted from the ultrasonic transmitter 2 is received by the ultrasonic receivers 3 and 4.

As shown in FIG. 2, when the transmission signal 13 from the ultrasonic transmitter 2 is used as a reference, the phase difference between the reception signals 14, 15 and the transmission signal 13 in the ultrasonic receivers 3, 4 is θ1,
θ2. Since the phase differences θ1 and θ2 change when the distance between the ultrasonic transmitter 2 and the ultrasonic receivers 3 and 4 changes, it is conventional to detect a minute displacement of the rock 1 by measuring the change. This is the method. In the present invention, θ
1. The method is characterized in that a method of detecting a small inclination and displacement of the rock 1 is obtained from the change of the difference between θ1 and θ2 and the distance between the ultrasonic receiver 3 and the ultrasonic receiver 4, etc., not from θ2 itself. is there.

Here, at an arbitrary measurement time, the distance between the ultrasonic transmitter 2 and the ultrasonic receiver 3 is L1, and the distance between the ultrasonic transmitter 2 and the ultrasonic receiver 4 is L2. The sound speed at this time is assumed to be c0. Next, when the rock 1 fluctuated from the original position at the time of measurement after an arbitrary time,
The distance between the ultrasonic transmitter 2 and the ultrasonic receiver 3 is changed from L1 to L1 + △ L1, and the ultrasonic transmitter 2 and the ultrasonic receiver 4
Is changed from L2 to L2 + △ L2, and assuming that the sound speed at that time has changed by the sound speed variation Δc from the previous measurement, the sound speed becomes c1 = c0 + △ c. Assuming that the frequency to be used is f, the temporal change amount of the phase difference θ1, θ2 between the transmission signal 13 and the reception signals 14, 15 is θ
When expressed as 1, θ2, the following equation is obtained.

[0020]

(Equation 1)

By measuring the phase differences θ1 and θ2 between the signal received by the ultrasonic receiver 3 and the signal transmitted by the ultrasonic transmitter 2, the minute displacement of the rock 1 can be obtained.
As shown in the second term on the right side, 1, θ2 is a variation of sound velocity Δc
Is the distance L1 between the ultrasonic transmitter 2 and the ultrasonic receiver 3 or the distance L between the ultrasonic transmitter 2 and the ultrasonic receiver 4
It changes greatly in the order of 2.

Here, from the phase differences θ1 and θ2 between the transmission signal 13 and the reception signals 14 and 15 obtained above, the difference θ1
When −θ2 is obtained, the following expression is obtained.

[0023]

(Equation 2)

First, assuming that the ultrasonic receivers 3 and 4 are equidistant from the ultrasonic transmitter 2, that is, L1 = L2,
The second term on the right side is cancelled. Alternatively, the change due to the sound speed fluctuation represented by the second term on the right-hand side changes in the order of L1−L2, and thus becomes negligibly small.
In addition, the use of θ1−θ2 makes it less likely to be affected by external noise having a frequency lower than the vicinity of the used frequency.

From the value of θ1−θ2, a minute displacement amount and inclination of the rock 1 can be obtained.
ψ is represented by the following equation.

[0026]

(Equation 3)

Here, d is the distance between the ultrasonic receivers 3 and 4. The effect of the sound speed c0 + △ c on the right side of the expression is canceled by the effect of the sound speed c0 + △ c included in θ1−θ2 obtained by measurement from the above expression.
There is no need to correct weather conditions such as sound speed.

FIG. 3 shows a combination of the first and second embodiments wherein the ultrasonic receiver is mounted on the rock 1 and the ultrasonic transmitter is mounted on a stable place at a certain distance from the ultrasonic receiver. Are shown.

The ultrasonic transmitter 2 comprises an ultrasonic transmitter 201 and an ultrasonic transmission circuit 202. Also, the ultrasonic receivers 3, 4, 5 are ultrasonic receivers 301, 401, 501.
And ultrasonic receiving circuits 302, 402, and 502. According to the first aspect, the transmission signal 13 of the ultrasonic wave emitted from the ultrasonic wave transmitter 201 is received as the reception signals 14 and 15 by the ultrasonic wave receivers 301 and 401. The reception signals 14 and 15 obtained by the ultrasonic receivers 3 and 4 are transmitted to the signal processing device 7 via the reception signal cables 303 and 403. In claim 2 (when three ultrasonic receivers are used), in addition to the above, the reception signal 16 obtained by the ultrasonic receiver 5 is added.
Is sent to the signal processing device 7 via the reception signal cable 503.

The transmission signal 13 is transmitted from the ultrasonic transmitter 2.
Is transmitted to the displacement measuring device 7 through the synchronous cable 203. In the above, the transmission of the signal to the displacement measuring device 7 is performed by the reception signal cable 30.
Although a wired cable such as 3, 403, 503 or the synchronization cable 203 is used, a wireless technology, which is a known technology, can be used instead.

Each signal transmitted to the displacement measuring device 7 is input to a signal processing circuit 9 in the displacement measuring device 7 to detect a phase difference between the transmission synchronization signal 17 and the reception signals 14, 15, and 16;
Comparison of phase difference between each of the ultrasonic receivers 3, 4, 5 and rock 1
After the detection of the minute inclination and the displacement of the object, the respective data are stored in the temporary storage device 11 and, for example, the temporal change of the phase difference and the displacement of the monitored object or the inclination and the interference fringe. Are displayed on the data display device 12. At this time, comparison with the previously measured data in the temporary storage device 11 is performed. The obtained data is transmitted to the storage device 8 via the data transmission cable 10 and stored.

FIG. 4 shows an embodiment of the displacement measuring apparatus according to the ninth aspect. 4 shows a processing flow of measuring the displacement amount of the rock 1 in the displacement measuring device 7. The processing flow in the displacement measuring device 7 is as follows. First, as shown in FIG.
7, and the phase differences θ1, θ2,
Step 1 for detecting θ3, then each ultrasonic receiver 3,
Step 2, Step 2 for comparing the phase difference between 4 and 5
From the value obtained in and the distance between the ultrasonic receivers 3, 4, and 5, etc.,
The method comprises: a step 3 for detecting a slight inclination and fluctuation of the rock 1; a step 4 for displaying the result on the data display device 12; and a step 5 for transmitting the result to the temporary storage device 11 and the storage device 8. At this time, if the minute inclination and displacement of the rock 1 are obtained from the phase differences θ1, θ2, and θ3 without performing the operation of Step 2, means for correcting weather conditions and the like are required. Therefore, by performing the operation in step 2, the error due to the weather conditions included in the phase differences θ1, θ2, and θ3 can be canceled.
The slight inclination and displacement of, without correcting the weather conditions,
That is, it is possible to always measure without being influenced by the weather condition. In step 2, θ1 and θ2,
By comparing the phase differences like θ1 and θ3, the three-dimensional displacement amount of the rock 1 can be obtained in step 3.

In FIG. 5, contrary to FIG. 3, the ultrasonic transmitter is mounted on the rock 1 according to claims 1 and 2, and the ultrasonic receiver is placed in a stable place at a certain distance from the ultrasonic transmitter. 1 shows a combination of the embodiments when the device is attached. At this time, the configuration of the apparatus, the processing flow, and the like are the same as those shown in FIGS. 3 and 4 except for the arrangement of the ultrasonic transmitter and the ultrasonic receiver.

FIG. 6 shows a case in which a plurality of ultrasonic receivers are mounted on the rock 1 and a plurality of ultrasonic transmitters are mounted at a stable place at a fixed distance therefrom. The following shows an example. Conversely, when a plurality of ultrasonic receivers are mounted on the rock 1 and a plurality of ultrasonic transmitters are mounted at a stable location separated by a certain distance therefrom, the ultrasonic transmitter and the ultrasonic It is the same except that the arrangement of the receiver is different. This is the embodiment of claims 1 and 2, FIG.
Although the principle is the same as that shown in FIG. 5, since a plurality of ultrasonic transmitters are used, if ultrasonic transmitters having different transmission frequencies are used, the displacement amount of the monitored object in various orders Can be measured.

Next, when using an ultrasonic interference wave, since two or more ultrasonic transmitters or receivers are used, the influence of weather on the sound wave propagation path equally affects the transmission signal or the reception signal. Therefore, it is less affected by weather conditions. For example, if the transmission signals of the two ultrasonic transmitters 2 and 6 are p1 and p2, the amplitude is E, and the delay amount between the transmission signals p1 and p2 is τ1, the transmission signals p1 and p2 are represented by the following equations.

[0036]

(Equation 4)

At an arbitrary measurement time, the ultrasonic transmitter 2
The distance between the ultrasonic transmitter 3 and the ultrasonic receiver 3 is L1, and the ultrasonic transmitter 6
And the distance between the ultrasonic receiver 3 and L2,
Assuming that the sound speed and the propagation loss in the adjacent sound wave propagation paths are equal and the sound speed is c0, the reception signal s1 at the ultrasonic receiver 3 is a superposition of the transmission signals p1 and p2, and is expressed by the following equation. You.

[0038]

(Equation 5)

When the envelope detection of the received signal s1 is performed and the carrier component is removed, the envelope detection signal a1 is expressed by the following equation.

[0040]

(Equation 6)

Detecting the delay amount τ1 of the transmission signals p1 and p2 in the expression such that the envelope detection signal s2 becomes 0, the following expression is obtained.

[0042]

(Equation 7)

Next, at the time of measurement after an arbitrary time,
Assuming that the rock 1 has fluctuated from the original position, the distance between the ultrasonic transmitter 2 and the ultrasonic receiver 3 is from L1 to L1 +
To ΔL1, the distance between the ultrasonic transmitter 2 and the ultrasonic receiver 4 changes from L2 to L2 + △ L2, and the sound speed at that time changes by the sound speed fluctuation Δc from the previous measurement. Then, the sound speed c1 = c0 + △ c, the amplitude of the transmission signals p3 and p4 of the ultrasonic transmitters 2 and 6 is E, and the delay amount is τ2.
Then, the transmission signals p3 and p4 and the reception signal s2 at the ultrasonic receiver 3 are expressed by the following equation.

[0044]

(Equation 8)

[0045]

(Equation 9)

When the envelope detection of the received signal s2 is performed to remove the carrier component, the envelope detection signal a2 is expressed by the following equation.

[0047]

(Equation 10)

When the delay amount τ2 of the transmission signals p3 and p4 in the equation where the envelope detection signal a2 becomes 0 is detected, the following equation is obtained.

[0049]

[Equation 11]

Here, the difference between the delay amounts τ1 and τ2 is given by the following equation.

[0051]

(Equation 12)

The above equation has the same form as the equation shown in (Equation 2), and the second term on the right-hand side becomes sufficiently small to be less affected by weather conditions.

FIG. 7 shows an embodiment in which claims 4 and 10 are combined as an example. In this embodiment, the rock 1 is 2
The ultrasonic transmitters 2 and 6 are attached and fixed. The ultrasonic receiver 3 is installed at an arbitrary position on a line of a bisector perpendicular to a straight line connecting the two ultrasonic transmitters.

As shown in FIG. 8, the transmission waveforms of the ultrasonic transmitters 2 and 6 initially transmit discontinuous signals 18 and 19 having the same phase and the same amplitude and at certain intervals. From the relationship of the installation position, the reception waveform reaching the ultrasonic receiver 2 in FIG.
20 is obtained. The reception signal obtains the amplitude value of at1 of the reception waveform 20 at a time t1 after a predetermined time from the distance between the ultrasonic transmitters 3 and 4 and the ultrasonic receiver 2.

Here, as shown in FIG. 9, when the rock 1 moves from the original position A to the position B, as an example, the ultrasonic wave receivers 2 and 6 can receive the ultrasonic wave without changing the transmission waveforms. 2
Are apparently received at 21 and 2 in FIG.
The waveform 23 becomes the synthesized waveform 23. The received signal is obtained from the distance after the ultrasonic transmitters 2 and 6 and the ultrasonic receiver 3 have moved.
After a certain time t2, the amplitude value at2 of the received waveform 23 is obtained.

The displacement measuring device 7 shown in FIGS. 7 and 9 detects the amplitude values at1 and at2 that reach the beginning of the discontinuous signal received by the ultrasonic receiver 3, and temporarily stores the amplitude values at1 and at2.
1 or the data storage device 8 and the temporary storage device 11
Alternatively, the signal processing circuit 9 compares and compares the relationship between the amplitude value and the displacement direction or the displacement amount based on the interference pattern stored in the data storage device 8 and compares the obtained displacement direction or displacement amount with the data storage device 8 or Data display device 1
Output to 2.

FIG. 11 shows an embodiment in which the fifth and sixth aspects are combined. In this embodiment, one ultrasonic receiver 3 is attached to a rock, and a vertical line 2 connecting the ultrasonic transmitters 2 and 6 is formed.
The only difference is that the ultrasonic receiver 3 is installed on the line of equal lines, and the rest is exactly the same as the above-described embodiment.

FIG. 12 shows an embodiment in which claim 6 is added to an embodiment in which claims 4 and 10 are combined. In the present embodiment, the displacement measurement device 7 compares and detects the amplitude values at1 and at2 that reach the beginning of the discontinuous signal detected and stored by the signal processing circuit 9, and the signal processing circuit 9 determines the difference between the amplitude values. Is detected, a command is issued to the transmission waveform controller 24 to change the phase of the transmission waveform. The transmission waveform controller 24 changes the phase of the transmission waveform of one of the ultrasonic transmitters 2 or 6, or both of the ultrasonic transmitters 2 and 6, with time. At stored in the temporary storage device 11
The signal processing circuit 9 compares the amplitude value of at1 with the amplitude value of at2 that has been continuously detected and stored, and when at1 and at2 have the same amplitude again, the signal processing circuit 9 notifies the transmission waveform control device 24 of the change in the phase of the transmission waveform. Command to stop. At this time, the transmission waveform controller 24 outputs the phase information of the transmission waveform to the signal processing circuit 9 automatically or at the request of the signal processing circuit 9.
The signal processing circuit 9 detects a displacement direction or a displacement amount from the phase information input from the transmission waveform control device 24, the amplitude value at1 stored in the temporary storage device 11 or the data storage device 8, and the past value of at2. Then, the obtained displacement direction or displacement amount is output to the data storage device 8 or the data display device 12.

FIG. 13 shows an eighth embodiment. An arrangement C of the ultrasonic transmitter and the ultrasonic receiver in the front direction and an arrangement D of the ultrasonic transmitter and the ultrasonic receiver orthogonal to the ultrasonic transmitter and the ultrasonic receiver are provided for the monitored object. With the arrangement C of the ultrasonic transmitter and the ultrasonic receiver in the front direction, it is difficult to measure the displacement in the front-rear direction due to the displacement of the monitored object, but the arrangement C of the ultrasonic transmitter and the ultrasonic receiver is difficult. By performing the measurement using the arrangement D of the ultrasonic transmitter and the ultrasonic receiver that are orthogonal,
It is possible to measure the above-mentioned longitudinal displacement. The same can be said for other directions by changing the arrangement of the ultrasonic transmitter and the ultrasonic receiver.

[0060]

According to the technology provided by the present invention, the temperature, humidity, pressure, wind, rainfall, snowfall,
Because it is hardly affected by fog weather conditions, all-weather observations can be performed. Further, since the three-dimensional minute displacement measurement of the monitored object can be realized with a simple configuration, a low-cost system can be realized.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a rockfall monitoring system according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a relationship between a transmission ultrasonic signal and a reception ultrasonic signal shown in FIG.

FIG. 3 is an embodiment of the present invention.

FIG. 4 is a processing flow in a displacement measuring device having a signal processing circuit according to the present invention.

FIG. 5 is an embodiment in which the arrangement of the ultrasonic transmitter and the ultrasonic receiver shown in FIG. 3 is changed.

FIG. 6 relates to FIG. 3 and shows an embodiment in which a plurality of ultrasonic transmitters and ultrasonic receivers are used.

FIG. 7 is an embodiment of the present invention in which an ultrasonic interference wave is used.

FIG. 8 is an explanatory diagram showing a relationship between a transmission ultrasonic signal and a reception ultrasonic signal in FIG. 7;

FIG. 9 is an embodiment of the present invention where an ultrasonic interference wave is used.

FIG. 10 is an explanatory diagram showing a relationship between a transmission ultrasonic signal and a reception ultrasonic signal in FIG. 9;

FIG. 11 is an embodiment of the present invention in which an ultrasonic interference wave is used.

FIG. 12 is an embodiment of the present invention where an ultrasonic interference wave is used.

FIG. 13 shows an embodiment in which the arrangement of the ultrasonic transmitter and the ultrasonic receiver with respect to the monitored object is changed in the present invention.

[Explanation of symbols]

1: Object to be monitored 2: Ultrasonic transmitter 201: Ultrasonic transmitter 202: Ultrasonic transmission circuit 203: Synchronous cable 3, 4, 5: Ultrasonic receiver 301, 401, 501: Ultrasonic receiver 302, 402, 502: Ultrasonic receiving circuit 303, 403, 503: Received signal cable 6: Ultrasonic transmitter 601: Ultrasonic transmitter 602: Ultrasonic transmitting circuit 603: Synchronous cable 7: Displacement measuring device 8: Data Storage device 9: signal processing circuit 10: data transmission cable 11: temporary storage device 12: data display device 13, 18, 19, 21, 22: transmission signal 14, 15, 16, 20, 23: reception signal 17: synchronization signal 24: Transmission waveform controller θ1, θ2: Phase difference between transmission signal and reception signal at1, at2; Amplitude value of reception signal A, B: Position of rock 1 C, D: Ultrasonic transmitter and supersonic Position of wave receiver with respect to monitored object t, t1, t2: time c0, c1: sound speed, Δc: sound speed fluctuation L1: distance between ultrasonic transmitter 2 and ultrasonic receiver 3 △ L1: ultrasonic wave L2: distance between the ultrasonic transmitter 2 and the ultrasonic receiver 4 ΔL2: change in the distance between the ultrasonic transmitter 2 and the ultrasonic receiver 4 Minute f: frequency, E: amplitude value, d: distance between the ultrasonic receivers 3, 4 p1, p2, p3, p4: transmission signal s1, s2: reception signal, a1, a2: envelope detection signal τ1, τ2 : Delay amount of transmission signals p1 and p2

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Keiyoshi Katakura 216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside the Information and Communications Division of Hitachi, Ltd. (72) Inventor Yoshinobu Kanda, 216 shares in Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture In-house Hitachi, Ltd. Hitachi, Ltd. Information and Communication Division

Claims (10)

[Claims] 1. Two ultrasonic receivers are mounted on the surface of an object (a structure such as a rock, a protective wall, a bedrock, a bridge, etc.) which needs to be monitored, and the ultrasonic receiver is placed in a stable place at a fixed distance from the ultrasonic receiver. Attach one ultrasonic transmitter. At this time, the phase difference between the reception signal and the transmission signal obtained by the two ultrasonic receivers is detected and compared to measure the minute tilt and displacement of the monitored object. Or, conversely, one ultrasonic transmitter is attached to the monitored object, and two ultrasonic receivers are installed at a stable place separated by a certain distance, and the minute tilt and displacement amount of the monitored object are set. , A displacement measurement system that uses ultrasonic waves. 2. A plurality of ultrasonic receivers are attached to an object to be monitored, and one ultrasonic transmitter is attached to a stable place separated by a predetermined distance therefrom. Or 1
Attach the ultrasonic transmitters to the object to be monitored, and install a plurality of ultrasonic receivers in a stable place at a fixed distance away from each other. The displacement measuring system using ultrasonic waves according to claim 1, wherein the displacement is measured. 3. A plurality of ultrasonic receivers are mounted on a monitored object, and a plurality of ultrasonic transmitters are mounted on a stable place at a fixed distance from the plurality of ultrasonic receivers. The displacement measuring system using ultrasonic waves according to claim 1, wherein the displacement measuring system measures minute inclination and displacement. 4. At least two ultrasonic transmitters are attached to the object to be monitored, and one or more ultrasonic receivers are attached to a stable place separated by a certain distance therefrom. At that time,
By detecting the amplitude value signal of the interference wave of the ultrasonic wave transmitted and synthesized from each ultrasonic transmitter, the minute displacement direction or displacement amount of the monitored object is measured, and the recorded ultrasonic wave is used. Displacement measurement system. 5. One or more ultrasonic receivers are attached to the object to be monitored, and two or more ultrasonic transmitters are attached to a stable place at a fixed distance therefrom. At that time,
The minute displacement direction or displacement amount of the monitored object is measured and recorded by detecting the amplitude value signal of the interference wave of the ultrasonic wave transmitted and synthesized from each ultrasonic transmitter. A displacement measurement system using ultrasonic waves. 6. The displacement measuring system according to claim 4, further comprising means for arbitrarily changing two or more transmission signal phases transmitted by the ultrasonic transmitter, and comprising: Has a means for comparing the amplitude value signal of the interference wave of the ultrasonic wave obtained in the above with a preset detection threshold, or a recording signal that is recorded moment by moment, the displacement direction or displacement amount of the monitored object A displacement measuring system characterized by measuring and recording. 7. The air temperature, humidity, pressure, wind,
The method according to claim 1, wherein the apparatus is hardly affected by weather such as rainfall, snowfall, and fog, and enables all-weather measurement.
A displacement measurement system using any of the ultrasonic waves of 3, 4, 5, and 6. 8. The three-dimensional displacement of the monitored object is observed by changing the arrangement of the ultrasonic transmitter and the ultrasonic receiver with respect to the monitored object. A displacement measurement system according to any one of 3, 4, 5, 6, and 7. 9. A weather condition is obtained by taking a received signal received by an ultrasonic receiver as an input signal, determining a phase difference between the transmitted signal and the received signal, and comparing the phase difference between the ultrasonic receivers. A displacement measuring device characterized by detecting, outputting, recording, and displaying a slight inclination and displacement amount of a monitored object without being affected by the object. 10. A means for receiving a received signal received by an ultrasonic receiver as an input signal and comparing the amplitude value signal with a predetermined detection threshold value or a recorded signal recorded every moment. The displacement measuring apparatus according to claim 9, wherein the displacement direction and the displacement amount of the monitored object are detected, output, recorded, and displayed.