JPWO2020075296A1 - Condition monitoring device - Google Patents

Abstract

The first vibration measuring instrument (100-1) measures the vibration of the structure (2, 3) at the first position and generates the first vibration signal in the time domain. The second vibration measuring instrument (100-2) measures the vibration of the structure (2, 3) at a second position different from the first position and generates a second vibration signal in the time domain. The first signal processor (200-1) converts the first vibration signal from the time domain to the frequency domain to generate the first spectral signal. The second signal processor (200-2) converts the second vibration signal from the time domain to the frequency domain to generate a second spectral signal. The third signal processor (300) calculates the ratio of the first and second spectral signals to generate a spectral ratio signal. The damage detector (400) detects damage to the structure (2, 3) based on the spectral ratio signal.

Description

The present invention relates to a condition monitoring device that monitors the condition of a structure such as damage to the structure by measuring the vibration generated in the structure.

Patent Document 1 discloses a condition monitoring system that evaluates the soundness of piers over time with high accuracy. The system of Patent Document 1 measures the constant tremor of the bridge pedestal, calculates the power spectrum of the constant tremor signal, and has the area of the power spectrum in the range from frequency f ₀ to frequency f ₁ and vibration from frequency f _0. The spectrum score, which is the ratio to the area of the power spectrum in the range up to the frequency f ₂ larger than the number f ₁ , is calculated.

JP-A-2015-230206

In the system of Patent Document 1, when the frequency characteristic of the force applied to the structure to be monitored (that is, the pier) fluctuates, the response frequency of the structure fluctuates, so that the spectrum score also fluctuates, and the structure becomes abnormal. There is a possibility of erroneous determination that it has occurred. Therefore, the system of Patent Document 1 has a problem that the frequency characteristic of the force applied to the structure must be kept constant at all times.

Further, the area of the power spectrum in the range of frequencies f _{0 to} f _{1 and} the area of the power spectrum in the range of frequencies f _{0 to} f ₂ may change at the same ratio. Further, the power spectrum may fluctuate uniformly with the same tendency over the frequency range f _{0 to} f ₂ . In this way, if the area of the power spectrum of a plurality of frequency ranges changes at the same ratio, or if the power spectrum of the entire frequency band fluctuates uniformly with the same tendency, the structure to be monitored is damaged. However, there is a problem that the system of Patent Document 1 cannot detect damage to the structure.

An object of the present invention is that it is not necessary to keep the frequency characteristic of the force applied to the structure constant at all times, and no matter how the spectrum of the signal representing the vibration of the structure changes, the state of the structure It is an object of the present invention to provide a condition monitoring device capable of reliably detecting a change in the frequency.

The condition monitoring device according to one aspect of the present invention is
A first vibration measuring instrument that measures the vibration of the structure in the first position and generates a first vibration signal in the time domain.
A second vibration measuring instrument that measures the vibration of the structure at a second position different from the first position and generates a second vibration signal in the time domain.
A first signal processor that converts the first vibration signal from the time domain to the frequency domain to generate a first spectral signal, and
A second signal processor that converts the second vibration signal from the time domain to the frequency domain to generate a second spectral signal, and
A third signal processor that calculates the ratio of the first and second spectral signals to generate a spectral ratio signal, and
Includes a damage detector that detects damage to the structure based on the spectral ratio signal.

The condition monitoring device according to one aspect of the present disclosure does not need to keep the frequency characteristics of the force applied to the structure constant at all times, and how the spectrum of the signal representing the vibration of the structure changes. However, changes in the state of the structure can be reliably detected.

It is a block diagram which shows the structure of the state monitoring apparatus 1 which concerns on Embodiment 1 of this invention. It is a block diagram which shows the exemplary structure of each vibration measuring instrument 100-1 and 100-2 of FIG. It is a schematic diagram which shows the exemplary arrangement of the vibration sensor 110 of FIG. It is a schematic diagram which shows the other exemplary arrangement of the vibration sensor 110 of FIG. It is a block diagram which shows the exemplary configuration of each signal processor 200-1 and 200-2 of FIG. It is a block diagram which shows the exemplary configuration of the signal processor 300 of FIG. It is a schematic diagram for demonstrating the calculation of the exemplary spectrum ratio by the signal processor 300 of FIG. It is a block diagram which shows the exemplary structure of the damage detector 400 of FIG. It is a block diagram which shows the exemplary implementation example of each component of the state monitoring apparatus 1 of FIG. It is a block diagram which shows the structure of the damage detector 400A which concerns on 1st modification of Embodiment 1 of this invention. It is a block diagram which shows the structure of the damage detector 400B which concerns on the 2nd modification of Embodiment 1 of this invention. It is a block diagram which shows the structure of the condition monitoring apparatus 1A which concerns on Embodiment 2 of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing, the same reference numerals indicate similar components.

Embodiment 1.
FIG. 1 is a block diagram showing a configuration of a condition monitoring device 1 according to a first embodiment of the present invention. The condition monitoring device 1 of FIG. 1 monitors the condition of the structure such as damage to the structure by measuring the vibration generated in the structure to be monitored. Monitoring targets include any structure configured as a continuum, including, for example, long structures such as railroad rails, complex pipes, and pipes, and three-dimensional structures such as bridges, piers, and tunnels.

The condition monitoring device 1 of FIG. 1 includes vibration measuring devices 100-1 and 100-2, signal processors 200-1 and 200-2, a signal processor 300, a damage detector 400, and a display device 500. The vibration measuring device 100-1 measures the vibration of the structure in the first position and generates the first vibration signal in the time domain. The vibration measuring device 100-2 measures the vibration of the structure at a second position different from the first position and generates a second vibration signal in the time domain. The signal processor 200-1 converts the first vibration signal from the time domain to the frequency domain to generate the first spectral signal. The signal processor 200-2 converts the second vibration signal from the time domain to the frequency domain to generate a second spectral signal. The signal processor 300 calculates the ratio of the first and second spectral signals to generate a spectral ratio signal. The damage detector 400 detects damage to the structure based on the spectral ratio signal. The display device 500 displays the detection result of the damage detector 400.

In the present specification, the vibration measuring instruments 100-1 and 100-2 are also referred to as "first vibration measuring instrument" and "second vibration measuring instrument", respectively. Further, in the present specification, the signal processors 200-1 and 200-2 are also referred to as "first signal processor" and "second signal processor", respectively. Further, in the present specification, the signal processor 300 is also referred to as a "third signal processor".

Hereinafter, each component of the condition monitoring device 1 of FIG. 1 will be described in more detail.

First, the vibration measuring instruments 100-1 and 100-2 will be described.

FIG. 2 is a block diagram showing an exemplary configuration of each vibration measuring instrument 100-1 and 100-2 of FIG. The vibration measuring instruments 100-1 and 100-2 have similar configurations to each other. Each vibration measuring instrument 100-1 and 100-2 includes a vibration sensor 110, a low-pass filter 120, and an A / D converter 130.

The vibration sensor 110 is provided at a predetermined position in the structure to be monitored. The vibration sensor 110 generates an analog signal having a magnitude proportional to the physical quantity representing the vibration of the structure, and sends the generated signal to the low-pass filter 120. Physical quantities that represent the vibration of a structure include, for example, displacement, velocity, or acceleration of an object. The vibration sensor 110 may be any sensor that generates a signal indicating a physical quantity representing vibration, and includes, for example, a piezoelectric type acceleration sensor or a servo type acceleration sensor. The vibration of the structure may be a constant fine movement of the structure, or may be a vibration generated in response to an external force applied to the structure by an impulse hammer or the like.

The low-pass filter 120 cuts frequency components exceeding a predetermined frequency from the input signal, and sends a signal including the remaining frequency components to the A / D converter 130.

The A / D converter 130 converts the input signal from an analog signal to a digital signal at a predetermined sampling rate to generate a vibration signal. The A / D converter 130 does not necessarily have to constantly sample the input signal, and when it becomes necessary to detect damage to the structure (for example, at predetermined time periods or in user control). The signal may be sampled (depending on). For example, if the structure to be monitored is a rail of a railroad, the A / D converter 130 signals, for example, at a time period prior to a predetermined time period before the train passes a predetermined position on the rail. May be sampled.

FIG. 3 is a schematic view showing an exemplary arrangement of the vibration sensor 110 of FIG. FIG. 4 is a schematic view showing another exemplary arrangement of the vibration sensor 110 of FIG. In FIGS. 3 and 4, reference numeral 110-1 indicates a vibration sensor 110 of the vibration measuring device 100-1, and reference numeral 110-2 indicates a vibration sensor 110 of the vibration measuring device 100-2. FIG. 3 shows an example in which the vibration sensors 110-1 and 110-2 are arranged at both ends (that is, near the joint with the adjacent rail) of a long structure 2 such as a rail of a railway. Further, FIG. 4 shows an example in which the vibration sensors 110-1 and 110-2 are arranged in the three-dimensional structure 3 having a certain width, height, and depth, respectively. In the three-dimensional structure 3, it is desirable that the vibration sensors 110-1 and 110-2 are arranged as far apart from each other as possible. In the example of FIG. 4, the vibration sensors 110-1 and 110-2 are arranged in the vicinity of the vertices farthest from each other in the three-dimensional structure having a rectangular parallelepiped shape.

The vibration sensors 110-1 and 110-2 are arranged at different positions in the structure as shown in FIG. 3 or 4. The vibration measuring device 100-1 measures the vibration of the structure in the first position and generates the first vibration signal in the time domain. The vibration measuring device 100-2 measures the vibration of the structure at a second position different from the first position and generates a second vibration signal in the time domain. By arranging the vibration sensors 110-1 and 110-2 in this way, the vibration measuring instruments 100-1 and 100-2 can generate first and second vibration signals that are significantly different from each other. .. The vibration measuring device 100-1 sends the first vibration signal to the signal processor 200-1, and the vibration measuring device 100-2 sends the second vibration signal to the signal processor 200-2.

Next, each signal processor 200-1 and 200-2 will be described.

FIG. 5 is a block diagram showing an exemplary configuration of each of the signal processors 200-1 and 200-2 of FIG. The signal processors 200-1 and 200-2 have similar configurations to each other. Each signal processor 200-1 and 200-2 includes a frequency analyzer 210 and a communication interface 220.

The frequency analyzer 210 converts the input vibration signal from the time domain to the frequency domain to generate a spectral signal, and sends the generated spectral signal to the communication interface 220. The frequency analyzer 210 generates a spectral signal, for example, by performing a Fourier transform on an interval of a predetermined time length of the input vibration signal.

The communication interface 220 is communicably connected to the signal processor 300 by wire or wirelessly, and transmits a spectral signal to the signal processor 300.

The signal processor 200-1 converts the first vibration signal from the time domain to the frequency domain to generate the first spectral signal. The signal processor 200-2 converts the second vibration signal from the time domain to the frequency domain to generate a second spectral signal. The signal processors 200-1 and 200-2 synchronize with each other based on a synchronization signal (not shown), for example, by communicating with each other via the communication interface 220. As a result, the signal processors 200-1 and 200-2 process the first and second vibration signals generated at the same time by the vibration measuring instruments 100-1 and 100-2, and the first and second vibration signals are processed. Generates 2 spectral signals. The signal processor 200-1 sends the first spectral signal to the signal processor 300, and the signal processor 200-2 sends the second spectral signal to the signal processor 300.

Next, the signal processor 300 will be described.

FIG. 6 is a block diagram showing an exemplary configuration of the signal processor 300 of FIG. The signal processor 300 includes a communication interface 310 and a designated ratio calculator 320.

The communication interface 310 is connected to the signal processors 200-1 and 200-2 so as to be able to communicate by wire or wirelessly. The communication interface 310 receives the first spectral signal from the signal processor 200-1 and sends the received first spectral signal to the spectral ratio calculator 320. The communication interface 310 receives the second spectral signal from the signal processor 200-2 and sends the received second spectral signal to the spectral ratio calculator 320.

The spectral ratio calculator 320 calculates the ratio of the first and second spectral signals at predetermined time periods to generate a spectral ratio signal, and sends the generated spectral ratio signal to the damage detector 400. As mentioned above, the first and second spectral signals are represented in the frequency domain. The spectral ratio signal is generated, for example, by calculating the ratio of the intensities of the first and second spectral signals for each of a plurality of frequency components in a predetermined frequency band.

FIG. 7 is a schematic diagram for explaining the calculation of an exemplary spectral ratio by the signal processor 300 of FIG. The upper part of FIG. 7 shows the intensity of the exemplary first spectral signal generated by the signal processor 200-1. The middle part of FIG. 7 shows the intensity of an exemplary second spectral signal generated by the signal processor 200-2. The lower part of FIG. 7 shows an exemplary spectrum ratio signal generated by the signal processor 300. In the example of FIG. 7, the lower spectrum ratio signal is generated based on the upper and middle spectral signals. The spectral ratio signal, that is, the ratio of the first and second spectral signals, has a stable value regardless of the frequency characteristic of the force applied to the structure. Therefore, even when the vibration measuring instruments 100-1 and 100-2 constantly measure the fine movement of the structure, or when measuring the vibration generated in response to the external force applied to the structure by an impulse hammer or the like. Even if there is, almost the same spectrum ratio signal is generated as long as the state of the structure does not change.

Next, the damage detector 400 will be described.

FIG. 8 is a block diagram showing an exemplary configuration of the damage detector 400 of FIG. The damage detector 400 includes a storage device 410, a similarity calculator 420, and a comparator 430.

The current spectral ratio signal generated by the signal processor 300 is input to the storage device 410 and the similarity calculator 420.

The storage device 410 stores the current spectral ratio signal generated by the signal processor 300, and also continues to store the previously generated and stored past spectral ratio signal. The past spectral ratio signals represent the vibrations measured at a time period preceding the measured vibrations of the first and second vibration signals associated with the current spectral ratio signal by a predetermined time period. It is generated based on the second vibration signal. The storage device 410 is, for example, a non-volatile storage device.

The similarity calculator 420 calculates the similarity α by comparing the current spectrum ratio signal input from the signal processor 300 with the past spectrum ratio signal read from the storage device 410, and calculates the calculated similarity. Send to comparer 430.

The similarity α is calculated as follows, for example.

The similarity α of the spectral ratio signal may be defined as the Euclidean distance between the current spectral ratio signal Rnow and the past spectral ratio signal Rbefore as follows.

Here, A represents a frequency band used for calculating the similarity α, and f represents a plurality of frequency components included in the frequency band A. The current spectral ratio signal Rnow is represented as an element of a vector space composed of the ratio Rnow [f] of the first and second spectral signals in each frequency component f in the frequency band A. Similarly, the past spectral ratio signal Rbefore is represented as an element of a vector space composed of the ratio Rbefore [f] of the first and second spectral signals in each frequency component f in the frequency band A.

When the similarity α is calculated as the Euclidean distance, if the current spectral ratio signal Rnow is similar to the past spectral ratio signal Rbefore, the similarity α becomes smaller and the current spectral ratio signal Rnow and the past spectral ratio. When the similarity of the signal Rbefore is lost, the similarity α becomes large.

Further, the similarity α of the spectral ratio signal may be defined as the following equation as a mutual correlation coefficient between the current spectral ratio signal Rnow and the past spectral ratio signal Rbefore as another expression thereof. ..

Here, N represents the number of frequency components f belonging to the frequency band A.

When the similarity α is calculated as the mutual correlation coefficient, if the current spectral ratio signal Rnow is similar to the past spectral ratio signal Rbefore, the similarity α becomes large, and the current spectral ratio signal Rnow and the past When the similarity of the spectral ratio signal Rbefore is lost, the similarity α becomes smaller.

The comparator 430 detects damage to the structure by comparing the similarity α with a predetermined threshold value. When using a similarity α that increases when the similarity of the spectral ratio signal is lost, such as the Euclidean distance, the comparator 430 is used in the structure when the similarity α is greater than or equal to a predetermined threshold. Determine that damage has occurred. On the other hand, when a similarity α that becomes smaller when the similarity of the spectral ratio signals is lost, such as the mutual correlation coefficient, the comparator 430 uses the comparator 430 when the similarity α is equal to or less than a predetermined threshold value. , It is determined that the structure is damaged, and a result signal indicating the determination result is sent to the display device 500.

In the above example, when calculating the similarity, the values of the spectral ratio signals at a plurality of frequency components are taken into consideration. This causes damage to the structure, even if the area of the power spectrum in multiple frequency ranges changes at the same ratio, or the power spectrum of the entire frequency band fluctuates uniformly with the same tendency. The comparator 430 can correctly determine that the similarity between the current spectral ratio signal and the past spectral ratio signal has been lost and detect damage to the structure.

Next, a method for determining the frequency band used for calculating the similarity α will be described.

It is desirable that the frequency band used to calculate the similarity α represents only the characteristics of the structure. First, when not given external force to the structure, the frequency band A1 used to calculate the similarity α, the bandwidth f _a ~f _b and a low-pass filter 120 cut-off frequency f _c of the vibration sensor 110 When determined from the maximum frequency f _d which is defined by the mounting method of the vibration sensor 110 is defined by a physically effective bandwidth. In this case, the frequency band A1 _{is, A1 = [f a, min} (f b, f c, f d)] represented by. That is, the frequency band A1 is the frequency _{f a} and the lower limit is determined frequency _f b, _{f c,} and the minimum value of _{f d} as a band to a maximum.

Further, when an external force is applied to the structure, the frequency band B of the external force is measured in advance, and the frequency band B of the external force is removed from the frequency band A2 used for calculating the similarity α. But damage can be detected accurately. When an external force is applied to the structure, the frequency band A2 used to calculate the similarity α is represented by A2 = A1 \ B. The frequency band A determined in this way is not affected by an external force and reflects only the vibration characteristics of the structure itself. Therefore, when the frequency band A determined in this way is used, damage can be accurately detected even if the position where an external force is applied to the structure fluctuates due to vibration of the structure.

The similarity α may be calculated in the frequency band of free vibration of the structure. As a result, damage to the structure can be detected no matter how the vibration characteristics of the structure change.

Further, the similarity α is not limited to being calculated using one frequency band, and may be calculated using, for example, a plurality of partial bands obtained by dividing the frequency bands A1 or A2 determined as described above. Good. In this case, the similarity calculator 420 calculates the similarity between the current spectral ratio signal and the past spectral ratio signal in each of the plurality of subbands. When the comparator 430 uses a similarity that increases when the similarity of the spectral ratio signal is lost, the structure is damaged when the similarity corresponding to at least one subband is greater than or equal to the threshold. Judge that it has occurred. Similarly, when using a similarity that decreases when the similarity of the spectral ratio signal is lost, the comparator 430 is a structure when the similarity corresponding to at least one subband is below the threshold. Is determined to be damaged. As a result, damage to the structure can be detected with high sensitivity even when a specific frequency component of the vibration signal fluctuates.

Also, in order to determine that the structure is damaged, the similarity α is not limited to being compared with one threshold value, but is compared with a plurality of threshold values, for example, two threshold values. May be good. For example, different maintenance tasks may be performed to distinguish between severe and minor damage to a structure. For example, if the structure is a rail of a railroad, when the rail is completely broken, the train is immediately stopped and the broken rail is repaired, while when the rail is damaged but has not reached the break. , An operation mode such as repairing a damaged rail after the business is closed is conceivable. Therefore, it is necessary to distinguish between severe damage to the structure (eg complete breakage) and minor damage (eg damage that has not reached breakage). When the comparator 430 uses a similarity α that increases when the similarity of the spectrum ratio signal is lost, the comparator 430 sets two different thresholds k1 and k2 (k1 <k2) and sets the similarity α. The determination may be made as follows by comparing with the threshold values k1 and k2.

When k1 <α <k2: Minor damage When k2 <α: Serious damage

Similarly, when the similarity α that becomes smaller when the similarity of the spectrum ratio signal is lost is used, the severe damage and the minor damage of the structure may be distinguished and determined.

FIG. 9 is a block diagram showing an exemplary implementation example of each component of the condition monitoring device 1 of FIG. As shown in FIG. 9, at least a part of the frequency analyzer 210, the spectral ratio calculator 320, the similarity calculator 420, and the comparator 430 includes a general-purpose processor 1000, a memory 1010, an input / output device 1020, and data. Bus 1030 may be provided. The general-purpose processor 1000 reads the program stored in the memory 1010 via the data bus 1030 and executes a predetermined operation, whereby the frequency analyzer 210, the spectral ratio calculator 320, the similarity calculator 420, and / or The function of the comparator 430 is realized. The data bus 1030 is connected to other components via the input / output device 1020.

The frequency analyzer 210 may include a digital signal processor in place of or in addition to the general-purpose processor 1000.

The vibration measuring device 100-1 and the signal processor 200-1 may be integrated with each other, or the vibration measuring device 100-2 and the signal processor 200-2 may be integrated with each other. Further, the signal processor 300 and the damage detector 400 may be integrated with each other. Further, the signal processor 300 and the damage detector 400 may be integrated into one of the signal processors 200-1 and 200-2. Further, the signal processors 200-1 and 200-2, the signal processor 300, and the damage detector 400 are integrated with each other, and the vibration measuring device 100-1 and the signal processor 200-1 are connected by wire or wireless communication. Then, the vibration measuring device 100-2 and the signal processor 200-2 may be connected so as to be communicable by wire or wirelessly.

The state monitoring device 1 according to the first embodiment calculates a spectrum ratio signal indicating the ratio of the first spectrum signal and the second spectrum signal, and uses the spectrum ratio signal as the frequency characteristic of the force applied to the structure. Can be used independently as a stable indicator to detect structural damage. Therefore, according to the condition monitoring device 1 according to the first embodiment, it is not necessary to keep the frequency characteristic of the force applied to the structure constant at all times.

Further, when the state monitoring device 1 according to the first embodiment calculates the similarity between the current spectrum ratio signal and the past spectrum ratio signal using the Euclidean distance or the mutual correlation coefficient, the spectra at a plurality of frequency components The value of the ratio signal is taken into consideration. Therefore, even if the structure is damaged and the area of the power spectrum of a plurality of frequency ranges changes at the same ratio, or the power spectrum of the entire frequency band fluctuates uniformly with the same tendency, the structure Damage to objects can be detected correctly.

Next, a modified example of the first embodiment will be described.

FIG. 10 is a block diagram showing the configuration of the damage detector 400A according to the first modification of the first embodiment of the present invention.

The damage detector 400A includes a storage device 410, a similarity calculator 420, a comparator 430A, a storage device 440, and a subtractor 450.

The storage device 410 and the similarity calculator 420 of FIG. 10 are configured in the same manner as the corresponding components of FIG.

The storage device 440 stores the current similarity calculated by the similarity calculator 420, and also continues to store the previously calculated and stored past similarity. The past similarity represents the first and second vibrations measured at a time period preceding the vibrations of the first and second vibration signals associated with the current similarity by a predetermined time period. It is generated based on the vibration signal of. The storage device 440 is, for example, a non-volatile storage device.

The subtractor 450 calculates the absolute value | α _now −α _before | of the difference between the current similarity α _now input from the similarity calculator 420 and the past similarity α _before read from the storage device 440. , The calculation result is sent to the comparator 430A.

The comparator 430A detects damage to the structure by comparing the difference in similarity | α _now −α _before | with a predetermined threshold value. When using a similarity α that increases when the similarity of the spectral ratio signal is lost, the comparator 430A has a structure when the difference in similarity | α _now −α _before | is greater than or equal to a predetermined threshold. Determine that the object is damaged. On the other hand, when the similarity α that becomes smaller when the similarity of the spectral ratio signals is lost is used, the comparator 430A uses the comparator 430A when the difference in similarity | α _now −α _before | is equal to or less than a predetermined threshold value. , It is determined that the structure is damaged, and a result signal indicating the determination result is sent to the display device 500. ..

Further, in order to determine that the structure is damaged, the difference in similarity | α _now −α _before | is not limited to being compared with one threshold value, and a plurality of threshold values, for example, 2 It may be compared with one threshold. When the comparator 430A uses a similarity α that increases when the similarity of the spectral ratio signal is lost, it sets two different thresholds k3 and k4 (k3 <k4), and the difference in similarity. By comparing | α _now −α _before | with the threshold values k3 and k4, the determination may be made as follows.

k3 << | α _now- α _before | <k4: minor damage k4 << | α _now- α _before |: serious damage

Similarly, when the similarity α that becomes smaller when the similarity of the spectrum ratio signal is lost is used, the severe damage and the minor damage of the structure may be distinguished and determined.

The damage detector 400A of FIG. 10 can detect a sudden change in the state of the structure by calculating the difference in similarity | α _now −α _before |.

FIG. 11 is a block diagram showing a configuration of a damage detector 400B according to a second modification of the first embodiment of the present invention.

The damage detector 400B includes a switch SW in addition to each component of the damage detector 400 of FIG. The switch SW is turned on only immediately after, for example, the maintenance work of the structure is completed. As a result, the storage device 410 was generated based on the first and second vibration signals representing the vibrations measured when the structure was in a healthy state (that is, immediately after the maintenance work of the structure was completed). Store the spectral ratio signal. The spectral ratio signal stored in the storage device 410 is preferably updated every time the maintenance work of the structure is completed and / or every time the structure of the structure is changed.

The similarity calculator 420 and the comparator 430 of FIG. 11 are configured similarly to the corresponding components of FIG.

According to the damage detector 400B, the current spectral ratio signal and the spectral ratio signal generated based on the first and second vibration signals representing the vibrations measured when the structure is in a healthy state. By calculating the similarity, damage can be reliably detected even if the damage to the structure progresses gradually.

Embodiment 2.
FIG. 12 is a block diagram showing the configuration of the condition monitoring device 1A according to the second embodiment of the present invention.

The condition monitoring device 1A includes a vibration measuring device 100-1 to 100-N, a selector 600, a signal processor 200-1, 200-2, a signal processor 300, a damage detector 400, and a display device 500.

The vibration measuring instruments 100-1 to 100-N measure the vibration of the structure at a plurality of positions and generate vibration signals in the time domain.

The selector 600 selects the first and second vibration signals from the plurality of vibration signals and inputs them to the signal processors 200-1 and 200-2.

The signal processors 200-1, 200-2, signal processor 300, damage detector 400, and display device 500 of FIG. 12 are configured in the same manner as the corresponding components of FIG.

According to the condition monitoring device 1A according to the second embodiment, by selectively using a plurality of vibration signals representing the vibration of the structure at a plurality of positions, the structure is more than the condition monitoring device 1 according to the first embodiment. You can accurately monitor the status of.

Further, the condition monitoring device 1A according to the second embodiment has the same effect as the condition monitoring device 1 according to the first embodiment.

The present invention is applicable to any structure constructed as a continuum, for example, long structures such as railroad rails, complex pipes, and pipes, and three-dimensional structures such as bridges, piers, and tunnels. Damage can be detected.

1,1A Condition monitoring device, 2 Long structure, 3 3D structure, 100-1 to 100-N vibration measuring instrument, 110, 110-1, 110-2 vibration sensor, 120 low frequency pass filter, 130 A / D converter, 200-1,200-2 signal processor, 210 frequency analyzer, 220 communication interface, 300 signal processor, 310 communication interface, 320 designated ratio calculator, 400, 400A, 400B damage detector, 410 storage Equipment, 420 similarity calculator, 430, 430A comparer, 440 storage, 450 subtractor, SW switch, 500 display, 600 selector, 1000 general purpose processor, 1010 memory, 1020 input / output device, 1030 data bus.

The condition monitoring device according to one aspect of the present invention is
A first vibration measuring instrument that measures the vibration of the structure in the first position and generates a first vibration signal in the time domain.
A second vibration measuring instrument that measures the vibration of the structure at a second position different from the first position and generates a second vibration signal in the time domain.
A first signal processor that converts the first vibration signal from the time domain to the frequency domain to generate a first spectral signal, and
A second signal processor that converts the second vibration signal from the time domain to the frequency domain to generate a second spectral signal, and
A third signal processor that calculates the ratio of the first and second spectral signals for each frequency component included in a predetermined frequency band to generate a spectral ratio signal, and a third signal processor.
Look including damage detector for detecting damage to the structure on the basis of the spectral ratio signal,
The damage detector detects damage to the structure by calculating the similarity between the current spectral ratio signal and the past spectral ratio signal and comparing the similarity with a predetermined threshold value .

The condition monitoring device according to one aspect of the present invention is
A first vibration measuring instrument that measures the vibration of the structure in the first position and generates a first vibration signal in the time domain.
A second vibration measuring instrument that measures the vibration of the structure at a second position different from the first position and generates a second vibration signal in the time domain.
A first signal processor that converts the first vibration signal from the time domain to the frequency domain to generate a first spectral signal, and
A second signal processor that converts the second vibration signal from the time domain to the frequency domain to generate a second spectral signal, and
A third signal processor that calculates the ratio of the first and second spectral signals for each frequency component included in a predetermined frequency band to generate a spectral ratio signal, and a third signal processor.
Includes a damage detector that detects damage to the structure based on the spectral ratio signal.
The damage detector calculates the similarity between the current spectrum ratio signal and the past spectrum ratio signal in a frequency band excluding the frequency band of the external force applied to the structure, and sets the similarity as a predetermined threshold value. Damage to the structure is detected by comparison.

Claims (8)

A first vibration measuring instrument that measures the vibration of the structure in the first position and generates a first vibration signal in the time domain.
A second vibration measuring instrument that measures the vibration of the structure at a second position different from the first position and generates a second vibration signal in the time domain.
A first signal processor that converts the first vibration signal from the time domain to the frequency domain to generate a first spectral signal, and
A second signal processor that converts the second vibration signal from the time domain to the frequency domain to generate a second spectral signal, and
A third signal processor that calculates the ratio of the first and second spectral signals to generate a spectral ratio signal, and
Includes a damage detector that detects damage to the structure based on the spectral ratio signal.
Condition monitoring device. The damage detector detects damage to the structure by calculating the similarity between the current spectral ratio signal and the past spectral ratio signal and comparing the similarity with a predetermined threshold value.
The condition monitoring device according to claim 1. The past spectrum ratio signal represents a vibration measured at a time point that precedes the time point at which the vibration of the first and second vibration signals associated with the current spectrum ratio signal is measured by a predetermined time period. Generated based on the first and second vibration signals,
The condition monitoring device according to claim 2. The past spectral ratio signal is generated based on the first and second vibration signals representing the vibrations measured when the structure is in a healthy state.
The condition monitoring device according to claim 2. The spectral ratio signal is represented as an element of a vector space consisting of the ratio of the first and second spectral signals in a plurality of frequency components in a predetermined frequency band.
The similarity is calculated as the Euclidean distance between the current spectral ratio signal and the past spectral ratio signal.
The condition monitoring device according to any one of claims 2 to 4. The spectral ratio signal is represented as an element of a vector space consisting of the ratio of the first and second spectral signals in a plurality of frequency components in a predetermined frequency band.
The similarity is calculated as a mutual correlation coefficient between the current spectral ratio signal and the past spectral ratio signal.
The condition monitoring device according to any one of claims 2 to 4. The damage detector calculates the similarity in the free vibration frequency band of the structure.
The condition monitoring device according to any one of claims 2 to 6. Multiple vibration measuring instruments that measure the vibration of a structure at multiple positions and generate vibration signals in the time domain, respectively.
It further includes a selector that selects a first and second vibration signal from the plurality of vibration signals and inputs them to the first and second signal processors.
The condition monitoring device according to any one of claims 1 to 7.

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