Anomaly monitoring system, anomaly monitoring method, computing device, and program

Abstract

An abnormality monitoring system (1) according to the present disclosure comprises: an optical fiber sensor (20) which is installed inside an attached pipe (P) provided on a bridge (B), and detects vibration at a plurality of positions in the longitudinal direction of the attached pipe (P); a communication device (30) that transmits the vibration detected by the optical fiber sensor (20) as vibration information; and a computation device (10) including a pattern determination unit (111) that determines in advance each of the initial shapes of vibration patterns at the natural frequencies of the bridge (B), the attached pipe (P), and a supporting beam (S) that supports the attached pipe (P) on the basis of the vibration information received from the communication device (30), and an abnormality detection unit (112) that detects abnormality in at least one of the bridge (B), the attached pipe (P), and the supporting beam (S) on the basis of a change from the initial shapes of vibration patterns based on the vibration information and / or the difference between the natural frequencies and the peak frequencies of vibration.

Description

Technical Field

[0001] The present disclosure relates to an abnormality monitoring system, an abnormality monitoring method, an arithmetic device, and a program.

Background Art

[0002] Conventionally, a damage monitoring technique for bridges by vibration monitoring has been known by utilizing the fact that the vibration characteristics change when damage occurs in a bridge (for example, Non-Patent Document 1). As indicators for damage detection, generally, natural vibration, attenuation, changes in natural vibration mode shapes, etc. are utilized. However, since the cost of installing an accelerometer for vibration monitoring is high, the use of damage monitoring techniques is limited to only a few bridges. Further, a technique (DAS: Distributed Acoustic Sensing) in which an optical fiber is used as a distributed vibration sensor has been established (for example, Non-Patent Document 2). It is known that if vibration is measured by DAS using an optical fiber sensor already laid in a bridge, it may be possible to reduce the sensor installation cost (for example, Non-Patent Document 3).

Prior Art Documents

Non-Patent Documents

[0004] However, the method of directly bonding optical fiber sensors to the bridge incurs installation costs. Furthermore, since bridges are built over rivers and other bodies of water, scaffolding is not available, requiring the use of special vehicles or temporary scaffolding for installation work. Thus, there was room for improvement in the technology of monitoring bridge abnormalities by detecting vibrations using optical fiber sensors.

[0005] In light of these circumstances, the purpose of this disclosure is to improve the technology for monitoring bridge abnormalities by detecting bridge vibrations using optical fiber sensors. [Means for solving the problem]

[0006] The abnormality monitoring system according to this disclosure comprises: an optical fiber sensor installed in an attached pipe of a bridge and detecting vibrations at multiple locations in the longitudinal direction of the attached pipe; a communication device that transmits the vibrations detected by the optical fiber sensor as vibration information; a pattern determination unit that determines the initial shape of the vibration pattern at the natural frequencies of the bridge, the attached pipe, and the support beam supporting the attached pipe in advance based on the vibration information received from the communication device; and an abnormality detection unit that detects at least one abnormality of the bridge, the attached pipe, and the support beam based on the change in the vibration pattern from the initial shape based on the vibration information, or at least one of the difference between the natural frequency and the peak frequency of the vibration.

[0007] Furthermore, the abnormality monitoring method according to this disclosure includes a detection step in which an optical fiber sensor provided in an attached pipe of a bridge detects vibrations at multiple locations in the longitudinal direction of the attached pipe; a transmission step in which a communication device transmits the vibrations detected by the optical fiber sensor as vibration information; a pattern determination step in which a computing device determines in advance the initial shape of the vibration pattern at the natural frequencies of the bridge, the attached pipe, and the support beam supporting the attached pipe, based on the vibration information received from the communication device; and an abnormality detection step in which at least one abnormality of the bridge, the attached pipe, and the support beam is detected based on the change in the vibration pattern from the initial shape based on the vibration information, or the difference between the natural frequency and the peak frequency of the vibration.

[0008] Furthermore, the computing device according to this disclosure includes a pattern determination unit that acquires vibration information indicating vibrations detected by optical fiber sensors installed in the attached pipes of a bridge, which detect vibrations at multiple positions in the longitudinal direction of the attached pipes, and determines in advance the initial shape of the vibration pattern at the natural frequencies of the bridge, the attached pipes, and the support beams that support the attached pipes, based on the vibration information, and an abnormality detection unit that detects at least one abnormality of the bridge, the attached pipes, and the support beams based on the change in the vibration pattern from the initial shape based on the vibration information, or at least one of the difference between the natural frequency and the peak frequency of the vibration.

[0009] Furthermore, the program relating to this disclosure causes a computer to function as a computing device relating to this disclosure. [Effects of the Invention]

[0010] According to this disclosure, it is possible to improve the technology for monitoring bridge abnormalities by detecting bridge vibrations using optical fiber sensors. [Brief explanation of the drawing]

[0011] [Figure 1] This figure shows an example of the configuration of an abnormality monitoring system according to one embodiment of the present disclosure. [Figure 2A] This diagram illustrates an example of how an accelerometer detects the natural frequencies of each component. [Figure 2B] This diagram illustrates an example of how an accelerometer detects the natural frequencies of each component. [Figure 3A] This is a diagram illustrating the natural vibration of a bridge. [Figure 3B] This is a diagram illustrating the natural vibration of the attached pipe. [Figure 3C] This is a diagram illustrating the natural vibration of a support beam. [Figure 4] This diagram illustrates multiple locations on the attached pipe where vibrations were detected by the optical fiber sensor. [Figure 5] This figure shows an example of the initial shape of a vibration pattern. [Figure 6] It is a diagram showing an example in which the output unit displays the abnormal occurrence position. [Figure 7A] It is a flowchart showing an example of the operation of an abnormality monitoring system according to an embodiment of the present disclosure. [Figure 7B] It is a flowchart showing an example of the operation of an abnormality monitoring system according to an embodiment of the present disclosure.

Mode for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present disclosure will be described with appropriate reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals. In the description of this embodiment, the description of the same or corresponding parts will be omitted or simplified as appropriate. The embodiments described below are examples of the configuration of the present disclosure, and the present invention is not limited to the following embodiments.

[0013] As shown in FIG. 1, the abnormality monitoring system 1 according to this embodiment includes an arithmetic device 10, an optical fiber sensor 20, and a communication device 30. In FIG. 1, the bridge B is shown as seen from the side in the longitudinal direction. The arithmetic device 10, the optical fiber sensor 20, and the communication device 30 are communicably connected to a network 40 including, for example, the Internet and a mobile communication network, etc., by wire or wirelessly. The communication method for transmitting and receiving information between each device is not particularly limited. The arithmetic device 10 and the communication device 30 may be integrated.

[0014] The arithmetic device 10 is a computer such as a server belonging to a cloud computing system or other computing systems. The arithmetic device 10 acquires by receiving vibration information from the communication device 30.

[0015] The optical fiber sensor 20 is laid in an attached pipe P provided beneath the bridge B. The optical fiber sensor 20 according to this embodiment includes those not used for communication. The optical fiber sensor 20 is capable of detecting vibrations in the time domain. The method for detecting vibrations using the optical fiber sensor 20 is well known and is described, for example, in Non-Patent Documents 2 and 3 mentioned above, so a detailed explanation is omitted.

[0016] The communication device 30 is capable of transmitting vibrations detected by the optical fiber sensor 20 as vibration information. The communication device 30 is installed, for example, connected to the end of the optical fiber sensor 20. The communication device 30 may be installed on the bridge B, or in a manhole located near the bridge B.

[0017] Network 40 includes the Internet, at least one Wide Area Network (WAN), at least one Metropolitan Area Network (MAN), or any combination thereof. Network 40 may also include at least one wireless network, at least one optical network, or any combination thereof. The wireless network is, for example, an ad hoc network, a cellular network, a local area network (Wi-Fi), a satellite communications network, or a terrestrial microwave network.

[0018] The bridge according to this embodiment consists of three members: bridge B, attached pipe P, and support beam S. When a vehicle passes over the bridge, bridge B, attached pipe P, and support beam S vibrate. It is known that the frequency at which each member vibrates most strongly, i.e., the natural frequency, differs. Figures 2A and 2B illustrate a method for detecting vibration by measuring the acceleration when a vehicle passes over the bridge. Figure 2A is a longitudinal cross-section of the bridge, and Figure 2B is a cross-section of line α in Figure 2A. In Figures 2A and 2B, acceleration is detected by accelerometers A through J, indicated by black-filled triangles.

[0019] Figure 3A shows time-domain data of bridge B vibration measured by accelerometers A through C, Figure 3B shows time-domain data of attached pipe P vibration measured by accelerometers D through F, and Figure 3C shows time-domain data of support beam S vibration measured by accelerometers G through J. Each of these data points was converted into frequency-domain data using a Fast Fourier Transform (FFT), and the data was then grouped and displayed for each component: bridge B, attached pipe P, and support beam S. It can be seen that at low frequencies shown in Figure 3A, bridge B vibrates strongly due to its natural vibration; at intermediate frequencies shown in Figure 3B, attached pipe P vibrates strongly due to its natural vibration; and at high frequencies shown in Figure 3C, support beam S vibrates strongly due to its natural vibration.

[0020] By utilizing the characteristic behaviors of each component according to its natural frequency, this embodiment makes it possible to distinguish the vibration of each component from the vibrations of the attached pipe P and support beam S detected by the optical fiber sensor 20, as described below, and to detect abnormalities. According to this embodiment, the cost of newly installing sensors such as accelerometers is eliminated. Furthermore, it becomes possible to monitor not only the bridge B but also the attached pipe P and support beam S, making maintenance more efficient or of higher quality. Thus, it is possible to improve the technology for monitoring bridge abnormalities by detecting bridge vibrations using optical fiber sensors.

[0021] <Configuration of the arithmetic unit 10> Referring again to Figure 1, an example of the configuration of the arithmetic unit 10 according to this embodiment will be described. As shown in Figure 1, the arithmetic unit 10 comprises a control unit 11, a storage unit 12, a communication unit 13, an input unit 14, and an output unit 15.

[0022] The storage unit 12 includes one or more memories, which may include, for example, semiconductor memory, magnetic memory, optical memory, etc. Each memory included in the storage unit 12 may function as, for example, main memory, auxiliary memory, or cache memory. The storage unit 12 stores any information used in the operation of the arithmetic unit 10. The storage unit 12 does not necessarily have to be located inside the arithmetic unit 10, and may be configured to be located outside the arithmetic unit 10.

[0023] The communication unit 13 includes at least one communication interface, which is, for example, a LAN interface. The communication unit 13 receives information used in the operation of the arithmetic unit 10 and transmits information obtained through the operation of the arithmetic unit 10. The communication unit 13 enables the arithmetic unit 10 to send and receive information with other devices via the network 40.

[0024] The input unit 14 includes at least one input interface. The input interface may be, for example, a physical key, a capacitive key, a pointing device, a touchscreen integrated with a display, or a microphone. The input unit 14 accepts operations to input information used for the operation of the arithmetic unit 10. Instead of being provided in the arithmetic unit 10, the input unit 14 may be connected to the arithmetic unit 10 as an external input device. Any connection method can be used, for example, USB (Universal Serial Bus), HDMI (High-Definition Multimedia Interface) (registered trademark), or Bluetooth (registered trademark).

[0025] The output unit 15 includes at least one output interface. The output interface is, for example, a display or a speaker. The display is, for example, an LCD (Liquid Crystal Display) or an organic EL (Electro Luminescence) display. The output unit 15 may include a user-wearable device such as VR goggles. The output unit 15 outputs information obtained by the operation of the computing unit 10. Instead of being provided in the computing unit 10, the output unit 15 may be connected to the computing unit 10 as an external output device. Any connection method can be used, for example, USB, HDMI (registered trademark), or Bluetooth (registered trademark).

[0026] The control unit 11 is implemented by a control arithmetic circuit (controller). This control arithmetic circuit may be composed of dedicated hardware such as an ASIC (Application Specific Integrated Circuit) or FPGA (Field-Programmable Gate Array), or it may be composed of a processor, or it may include both. The control unit 11 controls each part of the arithmetic unit 10 and executes processing related to the operation of the arithmetic unit 10. The control unit 11 can send and receive information with external devices via the communication unit 13 and the network 40.

[0027] The control unit 11 includes a pattern determination unit 111 and an abnormality detection unit 112.

[0028] The pattern determination unit 111 acquires vibration information indicating vibrations at multiple locations on the attached pipe P. Any method may be used to acquire the vibration information. In this embodiment, the pattern determination unit 111 acquires the information by receiving vibration information indicating vibrations detected by the optical fiber sensor 20 via the communication device 30. In some cases, the pattern determination unit 111 may also acquire the information by receiving vibration information indicating vibrations detected by the accelerometer.

[0029] Figure 4 is a diagram illustrating multiple locations of the attached pipe P where vibrations are detected by the optical fiber sensor 20 according to this embodiment. Figure 4 is a lateral view of the longitudinal direction of the bridge B. The multiple locations include a first location Sx where the attached pipe P is supported by the support beam S, and a second location Px between adjacent first locations Sx. In Figure 4, the first locations Sx are indicated by white circles from S1 to S C The second position Px is from P1 to P, indicated by the black circle. C As shown in Figure 4, from the first position S1 to S C And, from the second position P1 to P C This means that from S1 and P1 located at the ends of bridge B, to S at the central position C and P CThe numbers are numbered in increasing order. The number of the first position Sx and the second position Px is not limited to the example shown in Figure 4. As shown in Figure 4, the first position Sx and the second position Px where vibration is detected may extend up to the center of bridge B. However, it is not limited to this, and vibration may be detected from one end to the other end of bridge B.

[0030] The first position Sx is a measurement point for the vibration of the attached pipe P at each position supported by the support beam S. The second position Px is a measurement point for the vibration of the attached pipe P at the central position between the support beams S. The vibrations at the first position Sx and the second position Px detected by the optical fiber sensor 20 are transmitted as vibration information to the computing device 10 via the communication device 30.

[0031] The pattern determination unit 111 determines the initial shapes of the vibration patterns at the natural frequencies of the bridge B, the attached pipe P, and the support beam S that supports the attached pipe P, based on the vibration information. The shape of the vibration pattern, also called the mode shape, represents the distribution of displacement when the attached pipe P vibrates.

[0032] Specifically, the pattern determination unit 111 first identifies the natural frequencies of the bridge B, the attached pipe P, and the support beam S that supports the attached pipe P. If the natural frequencies are known using an accelerometer or the like, as described above, the information indicating the natural frequencies may be stored in the memory unit 12 beforehand. The pattern determination unit 111 can then read this information to identify the natural frequencies.

[0033] For example, the pattern determination unit 111 converts the time-domain signal indicated by the vibration information into a frequency-domain signal using a Fourier transform or the like, and identifies the frequency at which the amplitude of the signal peaks in that frequency domain (peak frequency) as the natural frequency. The natural frequencies, in ascending order, are bridge B, attached pipe P, and support beam S. The threshold values ​​for the natural frequencies of each member may be set in advance. For example, the pattern determination unit 111 may identify a high peak frequency of threshold X or higher as the natural frequency of support beam S, a medium peak frequency of threshold Y or higher but less than X as the natural frequency of attached pipe P, and a low peak frequency less than threshold Y as the natural frequency of bridge B. These threshold values ​​may be stored in the memory unit 12 in advance. As will be explained below with reference to Figure 5, since the attached pipe P and support beam S vibrate in accordance with the vibration of bridge B, the natural frequency of bridge B can also be identified from the vibration of the optical fiber sensor 20.

[0034] The pattern determination unit 111 may determine the natural frequency from the vibration at any one position among the vibrations at multiple positions of the attached pipe P indicated by the vibration information, or it may determine the natural frequency from the vibrations at multiple positions of the attached pipe P. The pattern determination unit 111 stores the information indicating the determined natural frequency in the storage unit 12. In this specification, the initial value of the peak frequency is referred to as the natural frequency.

[0035] Next, the pattern determination unit 111 determines the initial shapes of the vibration patterns of the bridge B, the attached pipe P, and the support beam S, which correspond to the natural frequencies.

[0036] The pattern determination unit 111 determines the initial shapes of the attached pipe P and the support beam S based on the vibrations of multiple first and second positions of the attached pipe P, using the acquired vibration information. In this case, the pattern determination unit 111 may determine the initial shape using the vibration of the support beam S as the first position Sx, which is the position where the attached pipe P is supported by the support beam S. Any method for analyzing modal shapes may be used to determine the initial shape.

[0037] The pattern determination unit 111 may determine the initial shape of bridge B as a shape that has been set in advance according to the vibrations indicated by the vibration information. The information indicating the pre-set shape of bridge B may be stored in the memory unit 12.

[0038] Referring to Figure 5, an example of the initial shape of the vibration pattern in this embodiment, determined by the pattern determination unit 111, will be explained. The first row of Figure 5 shows three frequency bands: "low," "medium," and "high." The "low" frequency band represents the natural frequency of bridge B, the "medium" frequency band represents the natural frequency of attached pipe P, and the "high" frequency band represents the natural frequency of support beam S. The second row of Figure 5 shows examples of the initial shape of the vibration pattern at each frequency. In each of the second row of Figure 5, the dashed lines connect the measurement points by the optical fiber sensor 20 before deformation due to vibration, and the solid lines connect the measurement points after deformation due to vibration. The initial shape of the vibration pattern in this embodiment includes the changes shown by these dashed and solid lines. In Figure 5, as in Figure 4, the first position Sx is shown as a white circle, and the second position Px is shown as a black circle. The fixed point at the end of bridge B is shown as a white square, and the vibration point of bridge B is shown as a black star. Note that the vibration points of bridge B are not measured by the optical fiber sensor 20 according to this embodiment.

[0039] The pattern determination unit 111 first reads the natural frequency values ​​for the bridge B, support beam S, and attached pipe P from the storage unit 12, and determines the initial shape of the vibration pattern for the members corresponding to those natural frequencies.

[0040] The second column of the first row in Figure 5 shows the initial shape of the vibration pattern at the natural frequency BF of bridge B, where the frequency band is "low". In this initial shape, bridge B is vibrating, and the support beam S and attached pipe P are displaced in accordance with the vibration of bridge B. The amplitude at the first position Sx follows the relationship Sc>Sx>S3>S2>S1, and the second position P X The amplitudes also follow the relationship Pc > Px > P3 > P2 > P1. That is, for both the first position Sx and the second position Px, the amplitude of the vibration increases from the end with the fixed point towards the center.

[0041] The second column of the second row in Figure 5 shows the initial shape of the vibration pattern at the natural frequency PF of the attached pipe P, where the frequency band is "medium". The amplitude at the second position Px is Pc≈Px≈P3≈P2≈P1, indicating that the amplitude of the attached pipe P is approximately the same regardless of the position. Furthermore, the amplitude at the first position Sx related to the support beam S is significantly smaller than that at Px. Thus, in the initial shape of this vibration pattern, only the attached pipe P vibrates, while the support beam S and bridge B do not vibrate.

[0042] The second column of the third row in Figure 5 shows the initial shape of the vibration pattern at the natural frequency SF of the support beam S, where the frequency band is "high". In this initial shape, irregular amplitudes are detected with respect to the longitudinal position of the attached pipe P at any first position Sx and any second position Px. The amplitudes of the attached pipe P and support beam S include not only the random case shown in Figure 5, but also the regular case where they are all of similar magnitude. Furthermore, in this initial shape of vibration pattern, the bridge B does not vibrate. Thus, in this initial shape of vibration pattern, the attached pipe P and support beam S are vibrating.

[0043] In this way, the pattern determination unit 111 determines the initial shape of the vibration pattern for each natural frequency of the bridge B, the attached pipe P, and the support beam S. The pattern determination unit 111 stores the information indicating the determined initial shape in the storage unit 12. The pattern determination unit 111 may also output the information indicating the determined initial shape via the output unit 15.

[0044] The anomaly detection unit 112 detects at least one anomaly in the bridge B, the attached pipe P, and the support beam S based on the change from the initial shape of the vibration pattern based on vibration information, or at least one of the difference between the natural frequency and the peak frequency of the vibration.

[0045] In this embodiment, the abnormality detection unit 112 first acquires vibration information indicating vibrations detected by the optical fiber sensor 20 installed inside the attached pipe P of the target bridge, by receiving it from the communication device 30, similar to the pattern determination unit 111 described above.

[0046] The anomaly detection unit 112 determines the shape of the vibration pattern based on the acquired vibration information. Specifically, the anomaly detection unit 112 first identifies the peak vibration frequency based on the vibration information. The anomaly detection unit 112 may identify the peak vibration frequency from the vibration at any one position among the vibrations at multiple positions of the attached pipe P indicated by the vibration information, or it may identify the peak vibration frequency from the vibrations at multiple positions of the attached pipe P. The anomaly detection unit 112 may identify the peak vibration frequency of the support beam S from the vibration information indicating the vibration at the first position Sx, and identify the peak vibration frequency of the attached pipe P from the vibration information indicating the vibration at the second position Px. The anomaly detection unit 112 stores the information indicating the identified peak vibration frequency in the storage unit 12.

[0047] The anomaly detection unit 112 may determine the shape of the vibration pattern after identifying members whose natural frequencies are less than a predetermined value from the identified peak frequency. For example, the anomaly detection unit 112 may determine the shape of the vibration pattern of bridge B if the identified peak frequency is less than a predetermined value from the natural frequency BF of bridge B, determine the shape of the vibration pattern of the attached pipe P if the identified peak frequency is less than a predetermined value from the natural frequency PF of attached pipe P, and determine the shape of the vibration pattern of the support beam S if the identified peak frequency is less than a predetermined value from the natural frequency SF of support beam S. The predetermined value may be set in advance and stored in the memory unit 12. Any method for analyzing mode shapes may be used to determine the shape of the vibration pattern.

[0048] The anomaly detection unit 112 compares the initial shape of the vibration pattern stored in the memory unit 12 with the shape of the determined vibration pattern to determine whether or not there has been a change from the initial shape. Any method may be used to determine whether or not there has been a change. For example, the anomaly detection unit 112 compares the shape of the vibration pattern of the identified attached pipe P with the initial shape of the vibration pattern of the attached pipe P determined by the pattern determination unit 111, which is stored in the memory unit 12, and determines that there has been a change if there is a difference of a predetermined value or more in the displacement at the first position Sx or the second position Px. This predetermined value may be stored in the memory unit 12 in advance. The anomaly detection unit 112 may output the first position Sx or the second position Px where it has been determined that a change has occurred to the output unit 15 as the anomaly occurrence position.

[0049] For example, the anomaly detection unit 112 determines that there has been a change in position S3 from the initial shape if there is a difference in displacement of a predetermined value or more between position S3 in the initial shape and position S3 in the shape of the determined vibration pattern. The anomaly detection unit 112 outputs the position S3 as the anomaly occurrence position to the output unit 15.

[0050] The anomaly detection unit 112 may detect a member that experiences natural vibration at a given natural frequency as an anomaly location if the difference between the peak frequency based on the acquired vibration information and the corresponding natural frequency is greater than or equal to a predetermined value. This predetermined value may be stored in the memory unit 12 in advance. For example, suppose the difference between the peak frequency of the support beam S based on the vibration information and the corresponding natural frequency SF of the support beam S is greater than or equal to a predetermined value. In this case, the anomaly detection unit 112 may detect the support beam S as an anomaly location.

[0051] The above is not limited to the above; for example, the anomaly detection unit 112 may first identify the peak vibration frequencies related to the bridge B, the attached pipe P, and the support beam S, and then identify the location where the anomaly occurred.

[0052] For example, suppose the difference between the natural frequency BF of bridge B and its peak frequency, and the difference between the natural frequency PF of attached pipe P and its peak frequency are less than a predetermined value, and the difference between the natural frequency SF of support beam S and its peak frequency is greater than or equal to a predetermined value. In this case, the abnormality detection unit 112 may detect support beam S as the location where the abnormality occurred.

[0053] For example, suppose the difference between the natural frequency BF of bridge B and its peak frequency, and the difference between the natural frequency SF of support beam S and its peak frequency are less than a predetermined value, and the difference between the natural frequency PF of attached pipe P and its peak frequency is greater than or equal to a predetermined value. In this case, the abnormality detection unit 112 may detect attached pipe P as the location of the abnormality.

[0054] For example, suppose the difference between the natural frequency PF of the attached pipe P and the corresponding peak frequency, and the difference between the natural frequency SF of the support beam S and the corresponding peak frequency are less than a predetermined value, and the difference between the natural frequency BF of the bridge B and the corresponding peak frequency is greater than or equal to a predetermined value. In this case, the anomaly detection unit 112 may detect bridge B as the location where the anomaly occurred.

[0055] The anomaly detection unit 112 outputs information indicating the location of the anomaly to the output unit 15.

[0056] The abnormality detection unit 112 may determine whether or not an abnormality has occurred for all of the bridge B, attached pipe P, and support beam S. If the abnormality detection unit 112 determines that an abnormality has occurred for all of the components, it may terminate the process. If there are still components for which an abnormality has not been determined, it may continue monitoring the target bridge by repeating the abnormality detection process described above.

[0057] Any method may be used to determine whether or not an abnormality has occurred for all components. For example, each time the abnormality detection unit 112 acquires vibration information, it stores information in the storage unit 12 indicating the components corresponding to natural frequencies whose difference from the peak frequency is within a predetermined value. The abnormality detection unit 112 may then refer to this information to determine whether or not an abnormality has occurred for all components.

[0058] The output unit 15 outputs information indicating the location of the anomaly detected by the anomaly detection unit 112. For example, the output unit 15 acquires information showing an image of the entire or a part of the target bridge, and overlays the area corresponding to the anomaly detected by the anomaly detection unit 112 onto the image. The image of the target bridge may be a photograph or a graphic. The information showing the image of the target bridge may be stored in the storage unit 12 in advance.

[0059] Figure 6 shows an example where the output unit 15 displays the location of an anomaly. In Figure 6, the location S3 where the anomaly of the target bridge was detected is displayed enclosed by a frame line Q. The output unit 15 may display the frame line in a different color depending on the date and time the anomaly was detected, the location of the anomaly, etc. The example shown in Figure 6 is not limited to this, and the location of the anomaly may also be indicated by symbols such as arrows. If the location of the anomaly is a bridge B, a support beam S, or an attached pipe P, the entire respective member may be enclosed by a frame line, or it may be indicated by symbols such as arrows.

[0060] The output unit 15 may output information indicating the location of the anomaly by voice, text, or other means. Furthermore, the anomaly detection unit 112 may transmit information indicating the location of the anomaly to the user's terminal device via the communication unit 13. This allows the bridge manager or inspection worker, as a user, to easily determine the location of the anomaly.

[0061] <Configuration of communication device 30> Referring again to Figure 1, an example of the configuration of the communication device 30 according to this embodiment will be described. As shown in Figure 1, the communication device 30 comprises a control unit 31, a storage unit 32, and a communication unit 33.

[0062] The storage unit 32 includes one or more memories, which may include, for example, semiconductor memory, magnetic memory, optical memory, etc. Each memory included in the storage unit 32 may function as, for example, a main memory, an auxiliary memory, or a cache memory. The storage unit 32 stores any information used for the operation of the communication device 30. The storage unit 32 does not necessarily have to be located inside the communication device 30, and may be configured to be located outside the communication device 30. The storage unit 32 stores information related to vibrations detected by the optical fiber sensor 20.

[0063] The communication unit 33 includes at least one communication interface. The communication interface is, for example, a LAN interface. The communication unit 33 receives information used for the operation of the communication device 30 and transmits information obtained through the operation of the communication device 30.

[0064] The control unit 31 is implemented by a control arithmetic circuit (controller). This control arithmetic circuit may be composed of dedicated hardware such as an ASIC or FPGA, a processor, or a combination of both. The control unit 31 controls each part of the communication device 30 and performs processing related to the operation of the communication device 30. The control unit 31 can send and receive information with external devices via the communication unit 33 and the network 40.

[0065] <Program> To enable the above-mentioned arithmetic unit 10, communication device 30, or abnormality monitoring system 1 to function, a computer capable of executing program instructions may be used. Here, the computer may be a general-purpose computer, a dedicated computer, a workstation, a PC (Personal Computer), an electronic notepad, etc. The program instructions may be program code, code segments, etc., for executing the required tasks.

[0066] A computer comprises a processor, a memory unit, an input unit, an output unit, and a communication interface. The processor may be a CPU (Central Processing Unit), MPU (Micro Processing Unit), GPU (Graphics Processing Unit), DSP (Digital Signal Processor), SoC (System on a Chip), etc., and may be composed of multiple processors of the same or different types. The processor controls each of the above components and performs various calculations by reading and executing programs from the memory unit. At least a part of these processes may be implemented in hardware. The input unit is an input interface that receives user input operations and acquires information based on user operations, such as a pointing device, keyboard, or mouse. The output unit is an output interface that outputs information, such as a display or speaker. The communication interface is an interface for communicating with external devices.

[0067] The program may be recorded on a computer-readable recording medium. Using such a medium, the program can be installed on a computer. The recording medium on which the program is recorded may be a non-transitory recording medium. Non-transitory recording media are not particularly limited, but may include, for example, CD-ROMs, DVD-ROMs, or USB memory sticks. Furthermore, the program may be downloaded from an external device via a network.

[0068] <Operation of Anomaly Monitoring System 1> Next, the operation of the abnormality monitoring system 1 according to this embodiment will be described with reference to Figures 7A and 7B. The operation of the abnormality monitoring system 1 corresponds to the abnormality monitoring method according to this embodiment. Of the operations of the abnormality monitoring system 1, the operation of the arithmetic unit 10 corresponds to the arithmetic method according to this embodiment.

[0069] In step S1 of Figure 7A, the optical fiber sensor 20 detects vibrations at multiple locations on the mounting pipe P and outputs the result to the communication device 30.

[0070] In step S2, the communication device 30 transmits vibration information indicating vibrations at multiple locations of the attached pipe P detected by the optical fiber sensor 20 to the computing device 10.

[0071] In step S3, the pattern determination unit 111 of the control unit 11 of the arithmetic unit 10 acquires vibration information indicating vibrations at multiple locations of the attached pipe P by receiving it.

[0072] In step S4, the pattern determination unit 111 identifies the natural frequencies of the bridge B, the attached pipe P, and the support beam S that supports the attached pipe P, based on the vibration information, and determines the initial shape of the vibration pattern at each natural frequency. The pattern determination unit 111 stores the determined initial shapes in the storage unit 12.

[0073] The initial shape of each component is determined by steps S1 to S4 described above, according to its natural frequency.

[0074] In step S5, the optical fiber sensor 20 detects vibrations at multiple locations on the attached pipe P installed on the target bridge and outputs the results to the communication device 30.

[0075] In step S6, the communication device 30 transmits vibration information indicating vibrations at multiple locations of the attached pipe P detected by the optical fiber sensor 20 to the computing device 10.

[0076] In step S7, the abnormality detection unit 112 of the control unit 11 of the computing device 10 acquires vibration information indicating vibrations at multiple locations of the attached pipe P by receiving it.

[0077] In step S8, the anomaly detection unit 112 identifies the peak frequency based on the acquired vibration information and determines the shape of the vibration pattern.

[0078] In step S9 of Figure 7B, the anomaly detection unit 112 detects at least one anomaly in the bridge B, the attached pipe P, and the support beam S based on the change in the shape of the vibration pattern determined in step S8 from the initial shape stored in the memory unit 12, or at least one of the difference between the natural frequency and the peak frequency of the vibration. The anomaly detection unit 112 outputs information indicating the location of the anomaly to the output unit 15.

[0079] In step S10, the output unit 15 outputs information indicating the location of the abnormality that was output from the abnormality detection unit 112. The abnormality detection unit 112 may also transmit the information indicating the location of the abnormality to the user's terminal device via the communication unit 13.

[0080] Steps S5 to S10 described above detect anomalies in the target bridge and output the location where the anomaly occurred.

[0081] In step S11, the abnormality detection unit 112 determines whether an abnormality has occurred for all members of the bridge B, attached pipe P, and support beam S. If it determines that an abnormality has occurred for all members (step S11: YES), the processing of the calculation unit 10 ends. If there are still members for which an abnormality has not been determined (step S11: NO), the processing of the calculation unit 10 returns to step S5, and monitoring of the target bridge may continue.

[0082] As described above, the abnormality monitoring system 1 according to this embodiment includes an optical fiber sensor 20 installed inside the attached pipe P of the bridge B and detecting vibrations at multiple locations in the longitudinal direction of the attached pipe P; a communication device 30 that transmits the vibrations detected by the optical fiber sensor 20 as vibration information; a pattern determination unit 111 that determines the initial shape of the vibration pattern at the natural frequencies of the bridge B, attached pipe P, and support beam S that supports the attached pipe P in advance based on the vibration information received from the communication device 30; and an abnormality detection unit 112 that detects at least one abnormality of the bridge B, attached pipe P, and support beam S based on the change from the initial shape of the vibration pattern based on the vibration information, or at least one of the difference between the natural frequency and the peak frequency of the vibration.

[0083] According to this embodiment, it is possible to monitor the vibrations of bridge B, the attached pipe P, and the support beam S by capturing the vibrations of the attached pipe P using the already installed optical fiber sensor 20, without the need to install new accelerometers or the like on bridge B. By comparing the initial shape of the vibration pattern or the natural frequency with a predetermined value, it is possible to easily detect abnormalities in each component. Therefore, it is possible to improve the technology for monitoring bridge abnormalities by detecting bridge vibrations using optical fiber sensors.

[0084] As described above, in the abnormality monitoring system 1 according to this embodiment, the multiple locations include a first location Sx where the attached pipe P is supported by a support beam S, and a second location Px between adjacent first locations Sx. The abnormality detection unit 112 detects the location where an abnormality occurred from among the multiple locations based on the changes from the initial shape at the first and second locations.

[0085] According to this embodiment, the vibration patterns of the attached pipes P and support beams S at multiple locations can be captured using the optical fiber sensor 20, making it possible to more accurately detect the location of abnormalities. Therefore, it is possible to improve the technology for monitoring bridge abnormalities by detecting bridge vibrations using an optical fiber sensor.

[0086] As described above, in the abnormality monitoring system 1 according to this embodiment, the computing device 10 further includes an output unit 15, and the output unit 15 outputs information indicating the location where the abnormality occurred.

[0087] According to this embodiment, a user who is a bridge inspector or manager can directly find out the location of the abnormality via the output unit 15, leading to a reduction in the time and cost required for inspection work. Therefore, it is possible to improve the technology for monitoring bridge abnormalities by detecting bridge vibrations using optical fiber sensors.

[0088] While this disclosure has been described based on the drawings and embodiments, it should be noted that those skilled in the art will find it easy to make various modifications or alterations based on this disclosure. Therefore, it should be noted that these modifications or alterations are within the scope of this disclosure. For example, the functions included in each block can be rearranged in a logically consistent manner, and multiple blocks can be combined into one or divided.

[0089] The following additional information is disclosed regarding the embodiments described above.

[0090] (Additional note 1) An optical fiber sensor installed inside an attached pipe of a bridge, which detects vibrations at multiple locations in the longitudinal direction of the attached pipe, A communication device that transmits vibrations detected by the optical fiber sensor as vibration information, Based on the vibration information received from the communication device, the initial shapes of the vibration patterns at the natural frequencies of the bridge, the attached pipe, and the support beam supporting the attached pipe are determined in advance. A computing device comprising a control unit that detects at least one abnormality in the bridge, the attached pipe, and the support beam based on the change in the vibration pattern from the initial shape based on the vibration information, or at least one of the difference between the natural frequency and the peak frequency of the vibration, and An anomaly monitoring system equipped with the following features. (Additional note 2) The plurality of positions include a first position where the support beam supports the attached pipe, and a second position between adjacent first positions. The abnormality monitoring system according to Appendix 1, wherein the control unit detects an abnormality location from among the plurality of locations based on the change from the initial shape at the first and second locations. (Additional note 3) The abnormality monitoring system according to Appendix 2, wherein the calculation device further includes an output unit, the output unit outputs information indicating the location of the abnormality. (Additional note 4) A detection step in which an optical fiber sensor installed inside an attached pipe of a bridge detects vibrations at multiple locations in the longitudinal direction of the attached pipe, A transmission step in which the communication device transmits the vibration detected by the optical fiber sensor as vibration information, The computing unit, A pattern determination step in which, based on the vibration information received from the communication device, the initial shape of the vibration pattern at the natural frequency of the bridge, the attached pipe, and the support beam supporting the attached pipe is determined in advance; An anomaly detection step that detects at least one anomaly in the bridge, the attached pipe, and the support beam based on the change in the vibration pattern from the initial shape based on the vibration information, or at least one of the difference between the natural frequency and the peak frequency of the vibration. An anomaly monitoring method, including the above. (Additional note 5) The plurality of positions include a first position where the support beam supports the attached pipe, and a second position between adjacent first positions. The anomaly monitoring method according to Appendix 4, wherein the anomaly detection step includes detecting an anomaly location from among the plurality of locations based on changes from the initial shape at the first and second locations. (Additional note 6) The abnormality monitoring method according to Appendix 5, further comprising an output step in which the computing device outputs information indicating the location of the abnormality. (Additional note 7) The system acquires vibration information indicating vibrations detected by optical fiber sensors installed inside the attached pipe of the bridge, which detect vibrations at multiple locations along the longitudinal direction of the attached pipe. Based on the aforementioned vibration information, the initial shapes of the vibration patterns at the natural frequencies of the bridge, the attached pipe, and the support beam supporting the attached pipe are determined in advance. A computing device comprising a control unit that detects at least one abnormality in the bridge, the attached pipe, and the support beam based on the change in the vibration pattern from the initial shape based on the vibration information, or at least one of the difference between the natural frequency and the peak frequency of the vibration. (Additional note 8) A non-temporary computer-readable medium storing a program for causing a computer to function as the arithmetic unit described in Appendix 7. [Explanation of Symbols]

[0091] 1. Anomaly Monitoring System 10 Arithmetic unit 11 Control Unit 12 Storage section 13 Communications Department 14 Input section 15 Output section 111 Pattern determination unit 112 Anomaly detection unit 20 Fiber Optic Sensors 30 Communication equipment 31 Control Unit 32 Storage section 33 Communications Department 40 Networks

Claims

1. An optical fiber sensor installed inside an attached pipe of a bridge, which detects vibrations at multiple locations in the longitudinal direction of the attached pipe, A communication device that transmits vibrations detected by the optical fiber sensor as vibration information, A pattern determination unit that determines the initial shape of the vibration pattern at the natural frequencies of the bridge, the attached pipe, and the support beam supporting the attached pipe, based on the vibration information received from the communication device, A calculation device comprising an abnormality detection unit that detects at least one abnormality in the bridge, the attached pipe, and the support beam based on the change in the vibration pattern from the initial shape based on the vibration information, or at least one of the difference between the natural frequency and the peak frequency of the vibration, and An anomaly monitoring system equipped with the following features.

2. The plurality of positions include a first position where the support beam supports the attached pipe, and a second position between adjacent first positions. The abnormality monitoring system according to claim 1, wherein the abnormality detection unit detects the location of the abnormality from among the plurality of locations based on the change from the initial shape at the first and second locations.

3. The abnormality monitoring system according to claim 2, wherein the calculation device further includes an output unit, the output unit outputs information indicating the location of the abnormality.

4. A detection step in which an optical fiber sensor installed inside an attached pipe of a bridge detects vibrations at multiple locations in the longitudinal direction of the attached pipe, A transmission step in which the communication device transmits the vibration detected by the optical fiber sensor as vibration information, The computing unit, A pattern determination step in which, based on the vibration information received from the communication device, the initial shape of the vibration pattern at the natural frequency of the bridge, the attached pipe, and the support beam supporting the attached pipe is determined in advance; An anomaly detection step for detecting at least one anomaly in the bridge, the attached pipe, and the support beam, based on the change in the vibration pattern from the initial shape based on the vibration information, or at least one of the difference between the natural frequency and the peak frequency of the vibration. An anomaly monitoring method, including the above.

5. The plurality of positions include a first position where the support beam supports the attached pipe, and a second position between adjacent first positions. The abnormality monitoring method according to claim 4, wherein the abnormality detection step includes detecting an abnormality location from among the plurality of locations based on changes from the initial shape at the first and second locations.

6. The abnormality monitoring method according to claim 5, further comprising an output step in which the computing device outputs information indicating the location of the abnormality.

7. The system acquires vibration information indicating vibrations detected by optical fiber sensors installed inside the attached pipe of the bridge, which detect vibrations at multiple locations along the longitudinal direction of the attached pipe. A pattern determination unit determines, in advance, the initial shape of the vibration pattern at the natural frequencies of the bridge, the attached pipe, and the support beam supporting the attached pipe, based on the vibration information. An anomaly detection unit that detects at least one anomaly in the bridge, the attached pipe, and the support beam based on the change in the vibration pattern from the initial shape based on the vibration information, or at least one of the difference between the natural frequency and the peak frequency of the vibration. A computing device equipped with the following features.

8. A program for causing a computer to function as the arithmetic unit described in claim 7.

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