JP2008122323A - Wire breakage detection method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a disconnection detection method of a wire or a cable and a device therefor capable of detecting surely a disconnection of the bent and stretched wire or cable. <P>SOLUTION: This disconnection detection method is described as follows: a high-frequency pulse is injected into the wire or the cable of a moving apparatus 2; a response signal is detected and recorded; disconnection characteristic quantities which are characteristic to a disconnection of the wire or the cable are extracted from the response signal waveform; and a disconnection of the wire or the cable is estimated from the disconnection characteristic quantities of the plurality of response signal waveforms recorded during bending and stretching movement of the wire or the cable. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electric wire / cable disconnection detection method and apparatus capable of reliably detecting the disconnection of an electric wire / cable to be bent and stretched.

  As a method for detecting the disconnection of an electric wire / cable (disconnection of an element wire, partial disconnection), there is a method of injecting a high-frequency pulse signal into the electric wire / cable and utilizing a reflected signal waveform appearing on the electric wire / cable.

  As a method of targeting electric wires / cables that are in operation in mobile equipment, high-frequency pulse signals having a frequency higher than the commercial frequency are injected into the electric wires / cables via capacitors, and electric wires are connected by CT (non-contact current detector). • Detect response signals generated on the cable. The response signal is recorded, and the disconnection is detected by examining the change over time of the response signal.

  Conventionally, measurement (injection of a high-frequency pulse signal and recording of a response signal waveform) is performed at regular intervals, and a differential waveform is obtained by comparing the initial waveform recorded first with the change waveform after the lapse of time. Based on the above, disconnection is determined. Furthermore, the disconnection location is estimated from the time difference between the high-frequency pulse signal and the difference waveform (reflection from the disconnection location) in the response signal waveform.

  As shown in FIG. 8, a differential waveform 201 between a response signal waveform (initial waveform; thick line) from a healthy wire / cable and a response signal waveform (change waveform; thin line) from a broken wire / cable is obtained. Appears during the wire / cable round-trip propagation time Ta (the time from when the high-frequency pulse signal passes through the detector until the signal reflected by the connecting part of the mobile device or the device-side high-frequency blocking inductor propagates to the detector) Yes. Note that the initial waveform and the change waveform have substantially the same shape, and the differential waveform 201 appears slightly. This differential waveform 101 is caused by an impedance change at the disconnection location. That is, the change waveform has a portion that was not in the initial waveform due to a partial reflection of the injected high-frequency pulse signal at the disconnection location, so that a differential waveform 201 as shown is obtained.

JP 2006-23105 A JP 2006-220460 A

  The wires / cables are bent and stretched (bend motion) as the mobile equipment moves, causing multiple wires that make up the conductor to fatigue and break. Since they are in contact with each other and sometimes separated from each other, the response signal waveform from the broken wire or cable may not be different from the response signal waveform from a healthy wire or cable. In such a case, it cannot be reliably detected that a disconnection has occurred.

  Accordingly, an object of the present invention is to solve the above-described problems and to provide a wire / cable break detection method and apparatus capable of reliably detecting a break in a bent wire / cable.

  In order to achieve the above object, the method of the present invention injects a high-frequency pulse into an electric wire / cable that is connected to a mobile device and performs a bending motion along with the movement of the mobile device, detects a response signal generated in the electric wire / cable, A waveform of the response signal is recorded, a characteristic feature of disconnection characteristic of the wire / cable disconnection is extracted from the response signal waveform, and a plurality of response signal waveform disconnections recorded during the bending motion of the wire / cable are recorded. The wire / cable disconnection is estimated from the feature amount.

  Even if the mobile device is stopped at a plurality of stop positions, a response signal waveform is recorded at the stop positions, and the wire / cable disconnection is estimated from the disconnection feature amount of the plurality of response signal waveforms. Good.

  A plurality of response signal waveforms may be recorded while the mobile device moves in a predetermined movement section, and the wire / cable disconnection may be estimated from the disconnection feature amount of the plurality of response signal waveforms.

  A peak value of a differential waveform obtained by subtracting the initial response signal waveform from the response signal waveform may be used as the disconnection feature amount.

  You may obtain | require the statistic of said several disconnection feature-value, and may estimate a disconnection from this statistic.

  The apparatus of the present invention also includes a high-frequency pulse generator that injects a high-frequency pulse into an electric wire / cable that is connected to the mobile device and performs a bending motion as the mobile device moves, and a detection that detects a response signal generated in the electric wire / cable , A waveform recorder for recording the waveform of the response signal, a disconnection feature amount extraction means for extracting a disconnection feature amount characteristic for disconnection of the wire / cable from the response signal waveform, and bending of the wire / cable A disconnection estimation means for estimating the disconnection of the electric wire / cable from the disconnection feature amount of a plurality of response signal waveforms recorded during the exercise is provided.

  The mobile device is stopped at a plurality of stop positions, the waveform recorder records a response signal waveform while stopping at the plurality of stop positions, and the disconnection estimation means determines the disconnection feature amount from the plurality of response signal waveforms. You may estimate the disconnection of an electric wire and a cable.

  The waveform recorder records a plurality of response signal waveforms while the mobile device moves in a predetermined movement section, and the disconnection estimating means determines whether the wire / cable is disconnected from the plurality of response signal waveform disconnection feature quantities. May be estimated.

  The disconnection estimation means may use a peak value of a differential waveform obtained by subtracting an initial response signal waveform from a response signal waveform as the disconnection feature amount.

  The disconnection estimation means may obtain a statistic of the plurality of disconnection feature quantities and estimate the disconnection from the statistics.

  The present invention exhibits the following excellent effects.

  (1) The disconnection of the bent electric wire / cable can be reliably detected.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  As shown in FIG. 1, the disconnection detecting device 1 of the present invention includes a high-frequency pulse generator 4 that injects a high-frequency pulse into an electric wire / cable 3 that is connected to a mobile device 2 and performs a bending motion as the mobile device 2 moves. A detector 5 for detecting a response signal generated in the electric wire / cable 3, a waveform recorder 6 for recording the waveform of the response signal, and a disconnection characteristic characteristic of disconnection of the electric wire / cable 3 from the response signal waveform Disconnection feature amount extraction means 7 for extracting the amount, and disconnection estimation means 8 for estimating the disconnection of the wire / cable 3 from the disconnection feature amounts of a plurality of response signal waveforms recorded during the bending motion of the wire / cable 3; It is equipped with.

  A capacitor 10 for injecting the high frequency pulse signal into the conductor 9 of the electric wire / cable 3 is provided between the high frequency pulse signal generator 4 for generating the high frequency pulse signal and the electric wire / cable 3. The detector 5 is provided in a signal injection line between the high-frequency pulse signal generator 4 and the capacitor 10, and from the injected high-frequency pulse signal to the far-end reflected wave reflected at the far end of the wire / cable 3. This is a high-frequency CT that can detect the response signal in a non-contact manner.

  Further, in this disconnection detecting device, the high frequency blocking inductor 12 is attached to the commercial frequency power source side of the electric wire / cable 3 so that the high frequency pulse signal does not flow into the commercial frequency power source 11. When the noise cut function of the mobile device 2 is weak, the high frequency blocking inductor 12 may be attached to the device side of the wire / cable 3 as well.

  In the electric wire / cable 3 to be detected, the mobile device 2 is supplied with power from the commercial frequency power supply 11 by the electric wire / cable 3. Since the mobile device 2 moves and the electric wire / cable 3 is frequently bent and stretched, disconnection occurs. In order to detect this, a high frequency pulse signal is injected from the high frequency pulse signal generator 4 into the electric wire / cable 3 via the capacitor 10. The high-frequency pulse signal passes through the detector 5, propagates through the conductor 9 of the electric wire / cable 3, is reflected by the connection portion of the mobile device 2 or the high-frequency blocking inductor 12, and propagates to the detector 5. The injected high frequency pulse signal and its response signal are detected by the detector 5 installed on the signal injection line and recorded as a response signal waveform in the high frequency waveform recording / measuring instrument 6.

  In the present embodiment, as shown in FIGS. 2A to 2C, the mobile device 21 moves horizontally, so that the farthest position 24 from the nearest position 23 is parallel to the straight line passing through the fixed portion 22. Move back and forth in the straight section. Further, the electric wire / cable 25 is laid and extended from the fixed portion 22 to the outside of the farthest position 24 along the straight line, and is then folded back into a U shape and connected to the mobile device 21. Therefore, as the mobile device 21 moves, the folding position of the electric wire / cable 25 moves, and the electric wire / cable 25 is greatly bent and stretched at the place where the folding position passes.

  3 to 5 are diagrams showing the operation of the mobile device 21 and sampling timing at which a high frequency pulse signal is injected and a response signal is recorded.

  In the embodiment shown in FIG. 3, the mobile device 21 moves at a constant speed from the nearest position 23 until it reaches the farthest position 24, reverses at the farthest position 24, and moves at a constant speed until it reaches the nearest position 23. It has an operation pattern of moving and waiting there for a while. Sampling timings s1, s2,... For performing injection of a high frequency pulse signal and recording of a response signal in one operation pattern are arbitrary. When the mobile device 21 repeats this operation pattern, sampling timings s1, s2, ... are also repeated.

  In the embodiment shown in FIG. 4, every time the mobile device 21 returns to the fixed part side, the mobile device 21 stops at a slightly different stop position and stands by, and the disconnection detection device 1 is in a state where the mobile device 21 is stopped at the stop position. At some point, high frequency test signals are injected and response signal waveforms are recorded.

  As illustrated, the mobile device 21 has an operation pattern in which it moves at a constant speed from the fixed part side to the farthest position 24, reverses at the farthest position 24, returns to the fixed part side at a constant speed, and waits for a while. . However, every time it returns to the fixed part side, it stops at a slightly different stop position 41, 42, 43 and waits. Sampling timings t1, t2, and t3 once in one operation pattern are performed while the mobile device 21 is stopped.

  In the embodiment shown in FIG. 5, the response signal waveform recording means 2 injects the high frequency test signal and generates the response signal waveform when the mobile device 21 is moving in a predetermined movement section (may be a return path or a reciprocation). Make a record.

  As illustrated, the mobile device 21 has an operation pattern in which it moves at a constant speed from the fixed part side to the farthest position 24, reverses at the farthest position 24, returns to the fixed part side at a constant speed, and waits for a while. . Sampling timings u1 to u4 are performed four times within one operation pattern, and are performed at regular time intervals during forward movement. In this way, sampling is performed while the mobile device 21 is moving in a predetermined movement section, so that a sample can be obtained when the mobile device 21 repeatedly passes through substantially the same position, which is advantageous in viewing statistical behavior. is there.

  Hereinafter, the operation of the disconnection detection device 1 of the present invention will be described.

As shown in FIG. 6, the response signal waveform (dashed line) 61 when the electric wire / cable is healthy and the response signal waveform (solid line) 62 when the electric wire / cable is disconnected are largely the same. , Partially different. The broken line is drawn so as not to overlap the solid line. The length of the wire / cable is 15 m, the pulse propagation speed is 2 × 10 ⁸ m / s, and the far end of the cable is open.

  In the healthy response signal waveform 61 and the disconnected response signal waveform 62, the peak 63 located on the time axis 0 ns corresponds to the incident pulse, and the peak 64 located on the time axis 150 ns corresponds to the far end reflection of the cable. In the disconnection response signal waveform 62, a small peak 65 located on the time axis 100 ns corresponds to reflection from the disconnection point. The peak 65 is drawn larger than actual.

  As shown in FIG. 7, the difference waveform 71 between the healthy response signal waveform 61 and the disconnection response signal waveform 62 in FIG. 6 has only a small peak 72 located on the time axis 100 ns. This peak 72 is derived from the peak 65 in FIG. The peak value of the peak 72 is referred to as a disconnection feature amount.

  In the prior art, when the peak value of the peak 72 exceeds a preset threshold value, it is detected that a disconnection has occurred and a disconnection location is detected. However, as described as a problem, even if a disconnection occurs, if the disconnected strands are in contact with each other, the peak 72 becomes small and cannot be detected. Therefore, in the present invention, the injection of the high frequency test signal and the recording of the response signal waveform are repeated while the electric wire / cable 25 is bent and stretched as the mobile device 21 moves.

  Now, as shown in FIG. 2A to FIG. 2C, it is assumed that the wire / cable 25 is broken at the break point 26. As already explained, as the mobile device 21 moves, the folding position of the electric wire / cable 25 moves, and the electric wire / cable 25 is greatly bent and stretched at the place where the folding position passes. For this reason, in FIG. 2 (a) and FIG.2 (c), the disconnection location 26 is linear, but in FIG.2 (b), the disconnection location 26 becomes U-shaped.

  2 (a) and FIG. 2 (c), when the broken portion 26 is linear, the broken strands may come into contact with each other. When they are in contact, the impedance of the broken portion 26 is small. Become. Therefore, when a high-frequency pulse is injected into the electric wire / cable 25 in this state, a differential waveform as shown in FIGS. 2D and 2F that does not include a reflected waveform from the broken portion 26 may be obtained. On the other hand, when the broken portion 26 becomes U-shaped as shown in FIG. 2B, the disconnected strands tend to be separated from each other, and when they are separated, the impedance of the broken portion 26 increases. Therefore, if a high frequency pulse is injected into the electric wire / cable 25 in this state, a differential waveform as shown in FIG. 2 (e) including the reflected waveform from the broken portion 26 is easily obtained.

  In the present invention, while the electric wire / cable 25 is bent and stretched as the mobile device 21 moves, the injection of the high frequency test signal and the recording of the response signal waveform are repeated, and the disconnection feature amount that appears due to the disconnection from these response signal waveforms. Therefore, even if the wire / cable 25 is disconnected, the disconnection feature amount is small when the differential waveform is as shown in FIGS. 2D and 2F, but as shown in FIG. When a differential waveform is obtained, the disconnection feature amount is larger than the threshold value, so that the disconnection is estimated.

  It is also possible to obtain a statistic of the disconnection feature quantity and estimate the disconnection rate from this statistic. For example, when the injection of the high-frequency test signal and the recording of the response signal waveform are repeated three times, the three differential waveforms of FIG. 2D to FIG. 2F are obtained, and the peak value that is the disconnection feature amount is 0, Suppose that it was 1,0. The variance of the disconnection feature amount is 0.33. From this, it is possible to estimate the disconnection rate to be 60% by substituting the variance into a calibration curve (Table 1 is the calibration curve map) prepared by examining the relationship between the variance of the disconnection feature amount and the disconnection rate in advance.

  Means and standard deviations can also be used as statistics. For example, when the injection of the high-frequency test signal and the recording of the response signal waveform are repeated three times, the three differential waveforms of FIG. 2D to FIG. 2F are obtained, and the peak value that is the disconnection feature amount is 0, Suppose that it was 1,0. The average of the disconnection feature amount is 0.33. From Table 1, the disconnection rate can be estimated to be 60%.

It is a lineblock diagram of a disconnection detecting device showing one embodiment of the present invention. (A)-(c) is a top view for demonstrating the movement of the moving apparatus in this invention, and the bending / stretching of an electric wire and a cable, (d)-(f) is a difference waveform corresponding to (a)-(c). FIG. It is a timing diagram which shows the movement pattern and sampling timing of the moving apparatus in this invention. It is a timing diagram which shows the movement pattern and sampling timing of the moving apparatus in this invention. It is a timing diagram which shows the movement pattern and sampling timing of the moving apparatus in this invention. It is a time waveform figure of a response signal waveform in the present invention. It is a time waveform figure of a difference waveform in the present invention. It is a time waveform figure of a response signal waveform for explaining the conventional disconnection detection method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Disconnection detection apparatus 2 Mobile equipment 3 Electric wire / cable stage 4 High frequency pulse generator 5 Detector 6 Waveform recorder 7 Disconnection feature extraction means 8 Disconnection estimation means 21 Mobile equipment 22 Fixed part 23 Nearest position 24 Farthest position 25 Electric wire / cable

Claims (10)

A high frequency pulse is injected into an electric wire or cable that is connected to a mobile device and performs a bending motion as the mobile device moves.
Detect response signals generated in the above wires and cables,
Record the waveform of the response signal;
From the response signal waveform, extract a characteristic disconnection characteristic amount of the wire / cable disconnection,
An electric wire / cable disconnection detection method, wherein the disconnection of the electric wire / cable is estimated from the disconnection feature quantities of a plurality of response signal waveforms recorded during the bending motion of the electric wire / cable. Stop the mobile device at multiple stop positions,
Record response signal waveforms while stopping at the plurality of stop positions,
The wire / cable disconnection detection method according to claim 1, wherein the disconnection of the wire / cable is estimated from a disconnection feature amount of the plurality of response signal waveforms. A plurality of response signal waveforms are recorded while the mobile device moves in a predetermined movement section,
The wire / cable disconnection detection method according to claim 1, wherein the disconnection of the wire / cable is estimated from a disconnection feature amount of the plurality of response signal waveforms.   The wire / cable disconnection detection method according to any one of claims 1 to 3, wherein a peak value of a differential waveform obtained by subtracting an initial response signal waveform from a response signal waveform is used as the disconnection feature amount.   5. The method for detecting a disconnection of an electric wire / cable according to any one of claims 1 to 4, wherein a statistic such as an average, variance, and standard deviation of the plurality of disconnection feature quantities is obtained and the disconnection is estimated from the statistics. A high-frequency pulse generator that injects a high-frequency pulse into an electric wire or cable that is connected to a mobile device and performs a bending motion along with the movement of the mobile device;
A detector for detecting a response signal generated in the electric wire / cable;
A waveform recorder for recording the waveform of the response signal;
Disconnection feature amount extraction means for extracting a disconnection feature amount characteristic of the wire / cable disconnection from the response signal waveform;
A breakage detection device for a wire / cable comprising a breakage estimation means for estimating a breakage of the wire / cable from a breakage feature amount of a plurality of response signal waveforms recorded during the bending motion of the wire / cable. . Stop the mobile device at multiple stop positions,
The waveform recorder records response signal waveforms while stopping at the plurality of stop positions,
7. The electric wire / cable disconnection detection apparatus according to claim 6, wherein the disconnection estimation means estimates the disconnection of the electric wire / cable from the disconnection feature amount of the plurality of response signal waveforms. The waveform recorder records a plurality of response signal waveforms while the mobile device moves in a predetermined movement section,
The wire / cable disconnection detection apparatus according to claim 6, wherein the disconnection estimation means estimates the disconnection of the wire / cable from the plurality of response signal waveform disconnection feature quantities.   9. The wire / cable disconnection detection according to claim 6, wherein the disconnection estimation means uses a peak value of a differential waveform obtained by subtracting an initial response signal waveform from a response signal waveform as the disconnection feature quantity. apparatus.   11. The electric wire according to claim 7, wherein the disconnection estimation means obtains statistics such as an average, a variance, and a standard deviation of the plurality of disconnection feature quantities, and estimates the disconnection from the statistics. Cable breakage detection device.

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