JP2015064348A - Sensor attaching base, and structure degradation analysis system using sensor attaching base - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide replacement easiness of a sensor that is used for abnormality determination of a state of a monitoring object, and to provide stability in abnormality determination performance (monitoring performance) at the time of sensor replacement.SOLUTION: A sensor attaching base (30) is used for a structure degradation analysis system which includes a controller that is attached to a fixing surface and monitors whether or not the state of a monitoring object is normal on the basis of acceleration information of the monitoring object that is outputted from a sensor installed at the monitoring object, and extracts at least one of inclination information of the monitoring object and intrinsic vibration number information as a feature value based on the acceleration information obtained from the sensor, and calculates a reference probability density distribution in normal state and monitoring probability density distribution at monitoring for the extracted feature value, and then based on comparison between the reference probability density distribution and the monitoring probability density distribution, monitors abnormality of the state of the monitoring object. Two sensors (20) are formed as a single plate that can be installed on the same plane.

Description

  The present invention can monitor deterioration of the mounting state of a structure such as a suspended structure in a tunnel or an overhang structure over a long period of time, and has a calibration function when replacing a sensor. The present invention relates to a sensor mounting base used in an object deterioration diagnosis system, and a structure deterioration diagnosis system using the sensor mounting base.

  As a method for detecting the deterioration state of the structure, it has been the mainstream that the inspection is carried out by visual inspection or some kind of instrument by a regular inspection by an inspector. In addition, a conventional technique is disclosed in which a quantitative inspection is easily and quickly performed on a crack that occurs over time in a structure such as a tunnel that is a degradation diagnosis target (see, for example, Patent Document 1).

  In Patent Document 1, a fluorescent dye that emits light by excitation light such as ultraviolet light or blue-based visible light is mixed in advance with a structure that is an object of deterioration diagnosis. Then, the structure is irradiated with a light source that emits ultraviolet light, blue-based visible light, or the like, and the occurrence of cracks is quantitatively determined by visual analysis or analysis processing of a captured image by a CCD camera or the like.

JP 2013-83493 A

  However, the prior art has the following problems.

  Although Patent Document 1 enables quantitative deterioration diagnosis, it is based on periodic inspection by an inspector to the last. Furthermore, it is necessary to mix a fluorescent dye in advance with respect to the structure to be deteriorated.

  On the other hand, in recent years, there has been a demand for a deterioration diagnosis system that can perform deterioration diagnosis of a structure with a shorter cycle than a periodic inspection and without an inspector. In addition, in tunnels, in addition to the deterioration of the walls and ceiling of the tunnel itself, it is necessary to quantitatively diagnose the deterioration of the mounting state of a suspended structure in the tunnel or a structure such as an overhang structure. There is sex. Furthermore, it is desired that not only a new structure but also an existing structure can be easily handled.

  In addition, when performing deterioration diagnosis by attaching a sensor to a structure, it is easy to replace the sensor when it is necessary to replace the sensor according to the life or failure of the sensor. It is desirable to prevent changes.

  The present invention has been made to solve the above-described problems, and obtains the ease of replacement of a sensor used for deterioration diagnosis of a mounting state of a structure and the stability of deterioration diagnosis performance at the time of sensor replacement. An object of the present invention is to obtain a sensor head mounting base used in a structure deterioration diagnosis system capable of performing the above and a structure deterioration diagnosis system using the sensor mounting base.

  The sensor head mounting base according to the present invention is attached to a fixed surface, and whether the mounting state of the structure is normal based on the acceleration information of the structure output from the sensor head installed in the structure to be subjected to deterioration diagnosis. A sensor controller for diagnosing whether or not, and extracting at least one of the tilt information and the natural frequency information of the structure as the feature quantity based on the acceleration information acquired from the sensor head, and regarding the extracted feature quantity, the normal state Calculating the probability density distribution for reference in diagnosis and the probability density distribution for diagnosis at the time of deterioration diagnosis, and diagnosing the deterioration of the mounting state of the structure based on the comparison between the probability density distribution for reference and the probability density distribution for diagnosis A sensor head mounting base used in a deterioration diagnosis system, which is formed as a single plate on which two sensor heads can be installed on the same plane. Is shall.

  In addition, the structure deterioration diagnosis system using the sensor mounting base according to the present invention is based on the acceleration information of the structure attached to the fixed surface and output from the sensor head installed in the structure that is the object of deterioration diagnosis. A structure deterioration diagnosis system comprising a sensor controller for diagnosing whether or not a structure is in a normal state, wherein the structure deterioration diagnosis system is executed by the sensor controller and is based on acceleration information acquired from a sensor head Feature amount extraction means for extracting at least one of structure inclination information and natural frequency information as feature amounts, and reference data obtained in a normal state based on the feature amounts extracted by the feature amount extraction means; If the diagnosis data obtained at the time of deterioration diagnosis has a significant difference of more than a predetermined amount, there is an abnormality in the mounting state of the structure. A determination means that determines that it is born, adopts the mounting base of the present invention as a fixed surface, and replaces an existing sensor and a new sensor installed together with the existing sensor in order to replace the existing sensor, Installed on the mounting base as two sensors, the feature quantity extraction means uses the existing sensor head and tilt information or natural vibration for each of the new sensor heads installed together with the existing sensor head to replace the existing sensor head. In order to extract the number information individually and correct the deviation between the mounting direction of the existing sensor head and the mounting direction of the new sensor head to match the coordinate axes, the tilt information extracted for the new sensor head Match the extracted tilt information or extract the natural frequency information extracted for the new sensor head from the existing sensor. Error correction means for calculating a transformation matrix for matching the natural frequency information extracted for the head, and the feature amount extraction means uses the transformation matrix to obtain acceleration information acquired from the new sensor head, Acceleration information corresponding to the case where an existing sensor head is used can be converted, and the determination means uses the inverse matrix of the conversion matrix, so that the reference data obtained based on the feature quantity extracted by the existing sensor head can be converted into a new sensor. It can be converted into reference data corresponding to the case where the head is used, and after removing the existing sensor head, the reference data accumulated based on the existing sensor head and a significant difference of more than a predetermined amount used for deterioration determination are continued. It is to be made available.

  According to the present invention, by configuring the two sensors as a single plate so that the surfaces to which the two sensors are attached have the same plane, it is easy to replace the sensor used for the deterioration diagnosis of the mounting state of the structure, and deterioration at the time of sensor replacement. It is possible to obtain a sensor head mounting base used in a structure deterioration diagnosis system capable of obtaining stability of diagnostic performance and a structure deterioration diagnosis system using the sensor head mounting base.

It is a block diagram of the structure deterioration diagnostic system in Embodiment 1 of this invention. It is a flowchart which shows the flow of the degradation diagnosis process by the 1st degradation diagnostic part in Embodiment 1 of this invention. It is the figure which showed the specific example regarding collection of the inclination information for 3 axes in Embodiment 1 of this invention. It is the figure which showed the specific example of probability density distribution regarding the inclination information for 3 axes in Embodiment 1 of this invention. It is the figure which showed the probability density distribution, probability density ratio, and evaluation value regarding a certain one-axis inclination information in Embodiment 1 of this invention. It is a flowchart which shows the flow of the degradation diagnostic process by the 2nd degradation diagnostic part in Embodiment 1 of this invention. It is the figure which showed the specific example regarding collection of the frequency information for 3 axes | shafts in Embodiment 1 of this invention. It is the figure which showed the calculation result of the power spectrum for 3 axes in Embodiment 1 of this invention. In Embodiment 1 of the present invention, the two-dimensional probability density distribution at the time of learning, the two-dimensional probability density distribution at the time of deterioration diagnosis, and the two-dimensional probability density ratio that is the ratio between the two calculated It is the figure which showed the specific example. It is explanatory drawing which showed the attachment base which makes it possible to install the acceleration sensor used with the structure deterioration diagnostic system in Embodiment 2 of this invention on the same plane.

  Hereinafter, a preferred embodiment of a structure deterioration diagnosis system of the present invention will be described with reference to the drawings.

  The present invention obtains a probability density distribution of a feature amount related to the inclination or natural frequency of a structure based on acceleration information obtained from a sensor attached to the structure to be diagnosed for deterioration, If there is a significant difference from the probability density distribution at the time of deterioration diagnosis, it is judged that some deterioration has occurred in the mounting state, and it has a calibration function at the time of sensor replacement as a technical feature Yes.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram of a structure deterioration diagnosis system according to Embodiment 1 of the present invention. The structure deterioration diagnosis system according to the first embodiment includes a sensor controller 10 and N (N is an integer of 2 or more) sensor heads 20 (1) to 20 (N).

  In the structure deterioration diagnosis system according to the first embodiment, it is possible to perform the deterioration diagnosis if at least one sensor head 20 is provided. In addition, the functions of the N sensor heads when a plurality of sensor heads are used are all common. Therefore, in the following description, when it is not necessary to distinguish each sensor head, the sensor head 20 is simply described without using the subscripts (1) to (N).

  Each of the N sensor heads 20 includes a sensor unit 21 and an acceleration information output unit 22, and is installed at different positions of the structure that is the object of the deterioration diagnosis. Here, specific examples of the structure include a suspended structure in a tunnel or an overhang structure, and the structure deterioration diagnosis system according to the present invention performs deterioration diagnosis of the mounting state of the structure over a long period of time. It will be.

  Examples of such a structure include jet fans, information boards, signs, and the like installed in the tunnel, and heavy objects that are suspended or overhang from the concrete of the casing forming the tunnel. Then, preferably two sensor heads 20 are installed on the structure, and each of them is installed at a portion which becomes both ends with respect to the structure, so that one of the displacements of the structure is largely captured.

  Therefore, the N sensor heads 20 are installed at positions away from each other with respect to the direction of the installation surface in order to capture the displacement of the structure greatly. Furthermore, the sensor head 20 may be replaced with two or more in order to facilitate replacement, and the monitoring state can be continued by replacing each pair.

  The sensor unit 21 is, for example, a three-axis acceleration sensor that has excellent responsiveness and can measure acceleration with a measurement range of about DC to several tens of Hz. Of the acceleration, the DC component represents the direction of gravity acceleration, that is, the inclination, and the AC component represents vibration. Thus, by using a triaxial sensor as the acceleration sensor, leveling is not required, and sensor output can be performed regardless of the direction of inclination or vibration. Therefore, if the direction of inclination can be specified such as leveling, two or one axis may be used.

  The acceleration information output unit 22 converts an analog signal related to the triaxial acceleration of the structure at the installation location of the sensor head into a digital signal at a predetermined sampling rate (for example, a sampling rate of 50 Hz), and the sensor is used as acceleration information. Transmit to the controller 10. In addition, the acceleration information output part 22 can transmit the acceleration information which is a digital signal to the sensor controller 10 via communication I / F, such as CAN and RS232C, as an example.

  The sensor controller 10 is installed at a position where the wiring reaches the N sensor heads 20 in the vicinity of the structure, and the mounting state of the structure is normal based on the acceleration information acquired from each of the N sensor heads 20. Determine whether or not. Specifically, the sensor controller 10 extracts the inclination information as the first feature amount based on the acceleration information, and performs the deterioration diagnosis of the attachment state of the structure, and the acceleration information. Based on this, it has the second deterioration diagnosis unit 12 that extracts the natural frequency information as the second feature quantity and performs the deterioration diagnosis of the attachment state of the structure.

  In addition, the sensor controller 10 includes a large-capacity communication I / F such as Ethernet (registered trademark), for example, so that the diagnosis result or data used for the diagnosis can be transmitted to a control device (not shown). Can do.

  In the case of a tunnel facility provided with a jet fan or the like as a structure, information in the tunnel is collected in a control device installed in the vicinity of the tunnel, which is provided in the vicinity of the tunnel, and is not shown in detail. The information is transferred to the remote monitoring and control device where there is, and the information is shared by both parties. In accordance with the deterioration diagnosis process described later, the result of determining that the deterioration has occurred is notified to each of the control devices with a display, an alarm sound, or the like. Such a determination result may be sent separately to a center apparatus of an equipment contractor or an inspection contractor of the deterioration diagnosis system, and can promptly respond when an abnormality occurs.

Further, the level for determining deterioration may be subdivided as follows, and the correspondence may be changed according to the level. For example, the deterioration judgment level is
Level 1: “Necessary to conduct detailed inspections at regular inspections (confirmation level)”
Level 2: “Need to check the site and consider future improvement plans (plan level)”
Level 3: “There is a need for immediate improvement, and there is a need to urgently go to the site (improvement level)”
Level 4: Emergency situation including collapse (emergency level) ”
Levels 1 and 2 can be simply displayed on the panel of each control device, and at levels 3 and 4, detailed alarm display and alarm sounding may be performed. .

  Furthermore, data used for continuous determination at the center device of the supplier may be collected and analyzed separately from multiple aspects, for example, to predict the time until reaching level 3. Tunnels are often monitored by a remote monitoring and control device at all times. However, in some cases, and in cases where daily management facilities are not sufficient, the primary emergency in the event of an emergency through the contractor's center device. It is also possible to make a staff member of the dealer take a response to confirm the situation and report the situation as a response.

The first deterioration diagnosis unit 11 and the second deterioration diagnosis unit 12 both compare the probability density distribution at the normal time of the structure to be monitored with the probability density distribution at the time of deterioration diagnosis, and are significant. This is common in that the deterioration of the structure is detected due to the difference. However, a specific signal processing method is used in the first deterioration diagnosis unit 11 that performs the deterioration diagnosis using the inclination information as the feature amount and the second deterioration diagnosis unit 12 that performs the deterioration diagnosis using the natural frequency information as the feature amount. These are different and will be described in detail below.
(1) Flow of deterioration diagnosis processing based on inclination information by first deterioration diagnosis unit 11 FIG. 2 is a flowchart showing a flow of deterioration diagnosis processing by the first deterioration diagnosis unit 11 according to Embodiment 1 of the present invention. It is. A specific deterioration diagnosis process by the first deterioration diagnosis unit 11 based on the inclination information will be described based on the flowchart of FIG.

  First, in step S <b> 201, the first deterioration diagnosis unit 11 extracts inclination information based on the acceleration information acquired from the acceleration information output unit 22 in the sensor head 20. Specifically, the first deterioration diagnosis unit 11 acquires X, Y, and Z-axis acceleration information at a sampling rate of 50 Hz, for example. And the 1st degradation diagnostic part 11 performs the low-pass filter process by a digital filter for every axis | shaft using this acceleration information. The cut-off frequency of the low-pass filter is, for example, about 0.1 Hz.

  Here, the low-frequency component of the triaxial acceleration including the DC component is equivalent to the tilt information. Then, the low-pass filtered slope information does not include a rapidly changing high frequency component. For this reason, information is not lost even if the sampling rate of the inclination data for detecting the deterioration is slowed. Specifically, if there is a sampling rate that exceeds twice the cutoff frequency, the sampling theorem can be satisfied, and for cutoff frequencies below 0.1 Hz, a sampling frequency of 0.2 Hz, ie, Sampling at intervals of 5 seconds is sufficient.

  FIG. 3 is a diagram showing a specific example relating to collection of inclination information for three axes in the first embodiment of the present invention. As shown in FIG. 3, the first deterioration diagnosis unit 11 collects inclination information for three axes at each sampling interval ΔT. The “tilt information” in the present invention means a tilt in a range from 180 degrees to −180 degrees when a certain reference direction is defined as 0 degrees, and is shown on the vertical axis in FIG. “Inclination information” is obtained by normalizing the inclination from 180 degrees to −180 degrees with respect to the reference direction from 1 to −1.

  Next, the first deterioration diagnosis unit 11 corrects the mounting direction of the sensor head 20 in step S202. Specifically, the first deterioration diagnosis unit 11 performs a matrix operation on the calibration data (affine transformation matrix elements) in the mounting direction of the sensor head 20 and the sampling data obtained in the previous step S201. The error in the mounting direction is corrected so that the coordinate axes of the respective sensor heads 20 coincide.

  The purpose of this step S202 is to align the coordinate axes regardless of the mounting direction of the sensor head 20, and since the sensor head 20 can detect tilt and vibration regardless of the direction with three axes, the sensor output is used as it is. Is not necessary.

  Next, in step S203, the first deterioration diagnosis unit 11 performs logarithmic processing (decibelization) on the inclination information after correcting the error in the mounting direction of the sensor head 20. For measurement of minute inclination information, for example, if an attempt is made to obtain a probability density distribution, which will be described later, based on a resolution of 1/1 million [G] units, the storage area required for this is enormous. Become. Therefore, the first deterioration diagnosis unit 11 of the first embodiment performs efficient quantization by logarithmizing the acceleration (decibelization) and obtaining the probability density distribution by classification based on the decibel data. Yes.

  Next, in step S <b> 204, the first deterioration diagnosis unit 11 performs a probability density distribution generation process in order to perform deterioration diagnosis based on inclination information. For example, the first deterioration diagnosis unit 11 creates a cumulative frequency distribution in units of 0.5 decibels using the slope information decibeled in the previous step S203, and performs a local smoothing process on the cumulative frequency distribution. Generate a probability density distribution. As the smoothing process, for example, a Gaussian function can be applied.

  The probability density distribution as the initial learning data at the time of installation is generated using, for example, data for about one month. On the other hand, the number of data of the probability density distribution created as current data at the time of deterioration diagnosis is generated based on data of the past 3 hours to 24 hours, for example.

  Further, it is not always necessary to continuously use the data acquired at the time of installation as the learning data at the normal time serving as the reference data. Since deterioration diagnosis is performed over a long period of time, it is possible to continuously update learning data in the process of performing deterioration diagnosis. And the probability density distribution adopted as continuous learning data at the time of deterioration diagnosis is generated based on, for example, data for the past several hours to several weeks.

  FIG. 4 is a diagram showing a specific example of the probability density distribution regarding the inclination information for three axes in the first embodiment of the present invention. The one-dimensional probability density distribution of each axis is expressed as a distribution that spreads from the midpoint to both sides as the positive slope and the negative slope increase with respect to the midpoint without slope.

  Next, in step S205, the first deterioration diagnosis unit 11 calculates the probability density distribution of each axis obtained during learning (corresponding to the reference data) from the probability density distribution of each axis obtained during deterioration diagnosis (corresponding to the data during diagnosis). And the probability density ratio data of the probability distribution for each axis is generated. As reference data, learning data updated by continuous learning data can be adopted in addition to the data at the time of initial setting.

  FIG. 5 is a diagram showing a specific example of probability density distribution, probability density ratio, and evaluation value related to certain one-axis inclination information in the first embodiment of the present invention. As shown in FIGS. 5A and 5B, when the peak of the probability density distribution is shifted, a distribution with a probability density ratio larger than 1 is generated around the shifted peak position. .

  Further, the first deterioration diagnosis unit 11 calculates the vector length by regarding the probability density ratio related to the slope calculated for each axis as a vector. Specifically, as shown in FIG. 5C, the first deterioration diagnosis unit 11 obtains a vector length as the Euclidean distance of the triaxial probability density ratio, and uses it as an evaluation value for deterioration diagnosis.

  Finally, in step S206, the first deterioration diagnosis unit 11 determines that the distribution data exceeds the reference value if the vector length of the probability density ratio is less than a predetermined deterioration determination reference value. Is present, it is determined that deterioration has occurred.

When the above contents are arranged, the following processing is performed when the deterioration diagnosis of the attachment state of the structure is performed using the probability density distribution regarding the inclination information.
[Feature 1] The inclination information is acquired by extracting the low frequency component of the acceleration information.
[Characteristic 2] The sampling rate of the inclination information can be slowed so that the information is not lost. For example, data can be collected at intervals of 5 seconds.
[Characteristic 3] The tilt data whose attachment direction has been corrected is converted to decibels to reduce the storage capacity and perform efficient quantization.
[Feature 4] Based on a predetermined decibel unit, the probability density distribution at the time of learning and deterioration diagnosis is calculated, and the vector length as the Euclidean distance of the probability density ratio at the time of three-axis learning and deterioration diagnosis is obtained, This is an evaluation value for deterioration diagnosis.
[Feature 5] If there is an evaluation value exceeding a predetermined reference value set in advance, it is determined that the inclination of the structure has reached an unacceptable level at the portion where the sensor head 20 is installed, and the deterioration state is determined. Judge quantitatively.

(2) Flow of deterioration diagnosis processing based on natural frequency information by the second deterioration diagnosis unit 12 Next, specific processing contents by the second deterioration diagnosis unit 12 will be described.

  FIG. 6 is a flowchart showing a flow of the deterioration diagnosis process by the second deterioration diagnosis unit 12 in the first embodiment of the present invention. A specific deterioration diagnosis process by the second deterioration diagnosis unit 12 based on the natural frequency information will be described based on the flowchart of FIG.

  First, in step S <b> 601, the second deterioration diagnosis unit 12 extracts frequency information based on acceleration information acquired from the acceleration information output unit 22 in the sensor head 20. Any structure has a natural frequency depending on the material, weight, shape, and support structure. For example, X, Y, and Z axis acceleration information is output from the sensor head 20 at a sampling rate of 50 Hz. However, large vibrations are not always generated. On the other hand, when performing frequency analysis, a high sampling rate is required, and a huge storage area is required to obtain data at all times.

  Therefore, the second deterioration diagnosis unit 12 according to the first embodiment, when acceleration exceeding a predetermined reference level set in advance is obtained in at least one of the acquired three-axis acceleration information. , A constant of 2n (for example, 512) is acquired from the past to the future.

  FIG. 7 is a diagram showing a specific example related to collection of frequency information for three axes in the first embodiment of the present invention. In FIG. 7, when acceleration data measured on the X-axis exceeds a reference level, a certain number of data consisting of past data and future data is stored for each of the three axes, using that time as an event trigger. Is illustrated.

  Next, the second degradation diagnosis unit 12 corrects the mounting direction of the sensor head 20 in step S602. Specifically, the second deterioration diagnosis unit 12 performs a matrix of calibration data (affine transformation matrix elements) in the mounting direction of the sensor head 20 and a certain number of data obtained in the previous step S601. By calculating, the error in the mounting direction is corrected so that the coordinate axes of the respective sensor heads 20 coincide with each other.

Next, in step S603, the second deterioration diagnosis unit 12 calculates a power spectrum by FFT processing for the error-corrected three-axis data, and obtains a natural frequency. FIG. 8 is a diagram showing calculation results of power spectra for three axes in the first embodiment of the present invention. The acceleration data includes a direct current component (slope component). Therefore, the second deterioration diagnosis unit 12 removes the low-frequency component from the power spectrum, the maximum maximum value (corresponding to f _1x , f _1y , and f _1z in FIG. 8) from the remaining spectrum, and the second (Corresponding to f _2x , f _2y , and f _2z in FIG. 8) are obtained, and these are set as the first natural frequency and the second natural frequency of each axis, respectively.

  Next, in step S604, the second deterioration diagnosis unit 12 creates a cumulative frequency distribution for each of the first natural frequency and the second natural frequency, and performs a local smoothing process on the cumulative frequency distribution. Individual probability density distributions for the first natural frequency and the second natural frequency are generated. Specifically, the second deterioration diagnosis unit 12 is defined by, for example, the first natural frequency and the second natural frequency obtained in the previous step S603 for each event trigger in the previous step S601. Each cumulative frequency distribution is created, and a local smoothing process is performed on each of the cumulative frequency distributions, thereby generating individual probability density distributions related to the first natural frequency and the second natural frequency. As the smoothing process, for example, a Gaussian function can be applied.

  The probability density distribution as the initial learning data at the time of installation is generated using, for example, data for about one month. On the other hand, the number of data of the probability density distribution created as current data at the time of deterioration diagnosis is generated based on data of the past 3 hours to 24 hours, for example.

  Further, it is not always necessary to continuously use the data acquired at the time of installation as the learning data at the normal time serving as the reference data. Since deterioration diagnosis is performed over a long period of time, it is possible to continuously update learning data in the process of performing deterioration diagnosis. The probability density distribution adopted as continuous learning data at the time of deterioration diagnosis is generated based on data of the past several hours to several weeks, for example.

  Next, in step S605, the second deterioration diagnosis unit 12 uses the two-dimensional probability density distribution of each axis (corresponding to the data at the time of diagnosis) obtained at the time of diagnosis as the two-dimensional probability density distribution of each axis obtained at the time of learning. By dividing by (equivalent to the reference data), the ratio between the two is calculated, and two-dimensional distribution data of the probability density ratio is generated for each axis. As reference data, learning data updated by continuous learning data can be adopted in addition to the data at the time of initial setting.

  FIG. 9 shows a two-dimensional probability density distribution at learning, a two-dimensional probability density distribution at the time of deterioration diagnosis, and a ratio of the two dimensions, calculated for the X axis as a certain axis in the first embodiment of the present invention. It is the figure which showed the specific example of the probability density ratio. As shown in FIG. 9, the probability density distribution related to the natural frequency is generated as two-dimensional data defined by the first natural frequency and the second natural frequency. This is the same as the idea of the one-dimensional probability density ratio regarding the inclination data by one deterioration diagnosis unit 11. The second deterioration diagnosis unit 12 uses a two-dimensional probability density ratio regarding two natural frequencies calculated for each axis as an evaluation value for deterioration diagnosis.

  Finally, in step S606, the second deterioration diagnosis unit 12 sets the normality if both of the three-axis probability density ratios are less than a predetermined reference value for deterioration determination, and any one of them is determined. If there is a two-dimensional distribution with a probability density ratio exceeding the reference value, it is determined that degradation has occurred.

When the above contents are arranged, the following processing is performed when the deterioration diagnosis of the mounting state of the structure is performed using the probability density distribution regarding the natural frequency information.
[Feature 1] With respect to acceleration information, natural frequency information is acquired by extracting a certain number of acceleration data including the point in time when acceleration data exceeding a reference level is obtained on any axis.
[Feature 2] Since the natural frequency information is used for subsequent frequency analysis, it is not appropriate to downsample the output rate from the sensor head 20. Therefore, when the acceleration data that exceeds the reference level in any axis is obtained as an event trigger, a certain number of acceleration data consisting of past data and future data is extracted and the natural frequency information is stored. The storage capacity is reduced.
[Characteristic 3] The power spectrum is calculated by performing frequency analysis on the natural frequency information in which the mounting direction is corrected, and the maximum maximum value and the second value are calculated from the remaining spectrum obtained by removing the low frequency component from the power spectrum. Is obtained, the first natural frequency and the second natural frequency of each axis are calculated.
[Feature 4] From the cumulative frequency distribution of each axis created for each of the first natural frequency and the second natural frequency calculated for each event trigger, the first natural frequency and the second natural frequency at the time of learning and deterioration diagnosis are calculated. An individual probability density distribution related to the natural frequency is calculated, and a probability density ratio at the time of learning and deterioration diagnosis for each of the three axes is obtained, respectively, and used as an evaluation value for deterioration diagnosis.
[Feature 5] If there is an evaluation value exceeding a predetermined reference value set in advance, it is determined that the vibration of the structure has reached an unacceptable level at the portion where the sensor head 20 is installed, and the deterioration state is determined. Judge quantitatively.

  As described above, according to the first embodiment, the first feature value related to the inclination and the second feature value related to the natural frequency are extracted based on the acceleration information obtained from the structure to be diagnosed for deterioration. Yes. For each feature amount, the probability density ratio between the probability density distribution at the time of learning corresponding to the reference data at normal time and the probability density distribution based on the measurement result at the time of deterioration diagnosis is obtained, and this probability density ratio is not acceptable. When the level is reached, it is determined that deterioration has occurred. As a result, the deterioration diagnosis of the mounting state of the structure can be performed quantitatively over a long period of time.

  In the above-described first embodiment, the deterioration diagnosis based on the first feature value related to the inclination and the deterioration diagnosis based on the second feature value related to the natural frequency have been described. It is possible to carry out the deterioration diagnosis quantitatively over a long period of time by performing only one.

  The deterioration diagnosis according to the first embodiment described above can be performed even when one sensor head is used as a minimum configuration. However, even if no deterioration has occurred at the location where the sensor head is installed, there is a possibility that the deterioration has occurred at other locations. Therefore, it is possible to expect improvement in detection accuracy by installing sensor heads at a plurality of locations and determining that the attachment deterioration of the structure has occurred when a deterioration state is detected by any of the sensor heads.

  Further, when the data of the two sensor heads can be used, in addition to the individual diagnosis results, the inclination is the difference between the inclinations of the two sensor heads, and the vibration frequency is the phase difference between the vibrations of the two sensor heads. As described above, deterioration diagnosis based on the probability density distribution can be performed, and further improvement in detection accuracy can be expected. In addition, regarding the vibration frequency, not only the phase difference but also the deterioration diagnosis can be performed similarly as the amplitude difference.

  Moreover, in Embodiment 1 mentioned above, the suspended structure in a tunnel or the overhang | projection structure was mentioned as an example of a degradation diagnosis object, However, This invention is not limited to this. If the structure is attached to the fixed surface and the attachment state may change over time, the deterioration diagnosis can be performed quantitatively over a long period of time. Further, by attaching a sensor head to an existing structure, it is possible to quantitatively diagnose a secular change in the mounting state of the structure after the installation of the sensor head.

  In the above-described first embodiment, the case of learning at the initial stage and the case of updating by learning at the time of deterioration diagnosis have been described as normal reference data. However, the present invention is not limited to this. Probability density distribution for judging normality does not need to be unique. For example, individual reference data is provided for each time zone, or separate reference data is provided for each event occurring in a structure. You can also. Furthermore, considering the secular change, it is also possible to use the probability density distribution at the initial stage and a new probability density distribution obtained by learning at the time of deterioration diagnosis.

In the method of the first embodiment, the first deterioration diagnosis unit 11 performs logarithmic processing (decibelization) on the inclination information after correcting the error in the mounting direction of the sensor head 20 in step S203. However, it is not always necessary to logarithmize.
In addition, the natural frequency information is obtained by extracting a certain number of acceleration data including the point in time when acceleration data exceeding the reference level is obtained on any axis. May be extracted to obtain the natural frequency information.

Embodiment 2
The first embodiment described above is an apparatus for diagnosing long-term deterioration of a structure using the sensor unit 21 that is a three-axis acceleration sensor, and measures the inclination from the static acceleration and calculates the natural frequency from the dynamic acceleration. The deterioration of the structure is diagnosed by measuring and detecting the time change. An advantage of using a three-axis acceleration sensor is that a change in inclination can be detected regardless of the posture at the time of installation. The direction of gravity can be known by measuring the static acceleration (DC component) applied to the acceleration sensor. The acceleration information obtained from the triaxial acceleration sensor has three components of three axes, and by appropriately setting α of the so-called affine transformation matrix, the sensor output with the gravitational direction as the Z axis is always set regardless of the posture. Can be obtained.

  If long-term deterioration diagnosis is continued using such a three-axis acceleration sensor, the life of the device will eventually reach its end, but if the life of the three-axis acceleration sensor is shorter than the life of the structure, the old 3 It is necessary to match the measurement data of the axial acceleration sensor (old sensor) with the measurement data of the three-axis acceleration sensor (new sensor) newly installed by replacement.

  Therefore, in the second embodiment, when the sensor head 20 is replaced due to a failure or a lifespan, the detection by the new sensor head is used so that the learning data collected by the old sensor head can be used to continue the monitoring state. A method for calibrating data will be described. In order to simplify the description, an explanation will be given below by taking as an example a calibration when replacing the old sensor head 20old installed at a certain place with a new sensor head 20new installed in the vicinity thereof.

  In the second embodiment, calibration is performed as follows by providing a period in which the new sensor head 20new is provided near the old sensor head 20old. When replacing the old sensor head 20old with the new sensor head 20new, the X, Y, and Z axis tilts axold, ayold, and azold detected by the old sensor head 20old, and X detected by the new sensor head 20new, The monitoring state can be continued by aligning the tilts axnew, aynew, and aznew of Y and Z (that is, by matching the coordinate axes of the old sensor head 20old and the new sensor head 20new). .

  At this time, when the old sensor and the new sensor are mounted adjacent to each other in a random posture, even if the Z-axis direction can be matched only by applying gravitational acceleration, the other axis directions can be matched. Therefore, it is necessary to apply acceleration from other directions. That is, when the conditions for measuring the application of gravitational acceleration and the application of periodic vibration are satisfied, the two sensors can be accurately positioned.

  However, when the three-axis acceleration sensor is installed on a monitoring object to which no clear periodic vibration is applied, the two sensor postures cannot be matched only with the acceleration information from the outside. Calibration of the postures of the two sensors in such an environment can be performed by providing a constraint that the old sensor and the new sensor are located on the same plane.

  Therefore, in the second embodiment, by using a base on which the old sensor and the new sensor can be installed on the same plane, the old sensor and the new sensor are attached to only one at the time of monitoring and both at the time of calibration. The gravitational acceleration direction can be measured and the error can be corrected.

  FIG. 10 is an explanatory view showing an attachment base that enables the acceleration sensor used in the structure deterioration diagnosis system according to the second embodiment of the present invention to be installed on the same plane. Specifically, the old sensor 20old and the new sensor 20new are installed on a mounting base 30 configured as a single plate so that the surfaces on which the two sensors are mounted have the same plane. It will be installed on the mounting surface. By using such a mounting base 30, it becomes possible to install the old sensor 20old and the new sensor 20new on the same plane, and it is possible to accurately calibrate the posture when the sensor is exchanged.

  Then, the controller 10 uses the three-axis inclinations axold, ayold, and azold detected by the old sensor 20old and the three-axis inclinations axnew, anew, and aznew detected by the new sensor 20new during the side-by-side period. An affine transformation matrix X that satisfies the relationship of Expression (1) is obtained.

  After the affine transformation matrix X has been calculated in this way, the controller 10 determines the three-axis inclinations a (xnew), a (ynew), a (znew) detected by the new sensor 20new, and the affine transformation matrix. By performing the calculation of the above expression (1) using X, it is possible to obtain data in which the coordinate axis coincides with the data obtained by the old sensor 20old by the new sensor 20new.

  In the above formula (1), the case where the transformation matrix is calculated based on the inclination information detected by each of the old sensor 20old and the new sensor 20new has been described. However, the present invention is not limited to this, and in calculating the transformation matrix, it is possible to use a detection result that changes according to the installation state of the sensor, and based on natural frequency information instead of inclination information. It is also possible to calculate a conversion matrix.

  The conversion by the affine transformation matrix may be applied to the data of the old sensor 20old without being applied to the detection result of the new sensor 20new, that is, the learning data collected by the old sensor 20old is converted in the reverse direction, You may process so that it may match a new sensor.

  Further, the calibration function described in step S202 of FIG. 2 in the first embodiment corrects so that the coordinate axis always coincides with a reference direction such as the direction of gravity without depending on the mounting position of the sensor 20. It is.

  Therefore, the calibration function according to the first embodiment is adapted to the reference coordinate axis instead of the coordinate function of the old sensor 20old.

  That is, in the second embodiment, for example, when reference information (corresponding to reference inclination information or reference natural frequency information) based on the direction of gravity is known, detection by the current sensor 20 is performed. A transformation matrix can be calculated by substituting information and this reference information into the above equation (1).

  Each time the sensor 20 is replaced, such a conversion matrix is obtained, and the controller 10 matches the reference gravity direction by converting the detection information from the sensor 20 using the conversion matrix. The normalized feature quantity based on the information can always be calculated without depending on the mounting direction of the sensor.

  In this way, by performing data conversion using the conversion matrix, after removing the old sensor 20old, based on the detection result by the old sensor 20old, the data at the time of learning that has been accumulated so far, It is possible to continue the monitoring state while maintaining the constant deterioration diagnosis performance by using the sensor data and the allowable level used for the deterioration determination as they are.

  As described above, according to the second embodiment, when exchanging sensors, a period is provided in which two new and old sensors are provided, and an affine transformation matrix is calculated from detection results of both sensors. Alternatively, when the sensor is replaced, an affine transformation matrix is calculated so that a detection result that coincides with a reference direction such as a gravity direction can be obtained. As a result, by applying the affine transformation, the data obtained with the sensor before replacement can be used effectively, and the influence on the deterioration diagnosis performance due to the difference in mounting direction due to sensor replacement is suppressed and kept constant. It is possible to maintain the deterioration diagnosis performance and continue the monitoring state.

  In addition, as described above, according to the second embodiment, two sensors are placed on the same plane by using the mounting base configured as a single plate so that the surfaces on which the two sensors are mounted have the same plane. It becomes possible to attach to. As a result, even when the sensor is replaced, posture calibration can be performed easily and accurately, and long-term stabilization of the performance of the structure deterioration diagnosis system can be realized.

  In the present invention, regarding a feature amount, when a significant difference is detected by comparing a probability density distribution during learning corresponding to normal reference data with a probability density distribution based on measurement results during monitoring. Therefore, it is determined that an abnormality has occurred in the state of the monitored object. In the above-described embodiment, the probability density ratio, which is the ratio of the respective probability density distributions at the time of learning and monitoring, is calculated, and whether or not there is a significant difference is detected. The case where abnormality determination of a state is performed is illustrated.

  However, the method for determining the abnormality of the state of the monitored object by detecting a significant difference by comparing the probability density distributions at the time of learning and at the time of monitoring is not limited to this. Laws 1 and 2 are also conceivable. When the probability density distribution obtained at the time of learning is used as a reference probability density distribution and the probability density distribution obtained at the time of monitoring is used as a diagnostic probability density distribution, as an alternative method 1 or 2, the following processing can be performed. Conceivable.

First, as an alternative method 1, if there is a distance between probability density distributions of a predetermined amount or more between the reference probability density distribution and the diagnostic probability density distribution, it is determined that there is a significant difference, and the monitoring object It can be determined that an abnormality has occurred in the state. Here, in calculating the distance between the probability density distribution, it is possible to adopt Kullback Leibler distance, known techniques such as Pearson distance, L ² distance.

  As an alternative method 2, a normal determination region and an abnormality determination region are set from the reference probability density distribution. Then, if there is a distribution included in the abnormality determination area in the diagnostic probability density distribution obtained at the time of monitoring, it is determined that there is a significant difference, and an abnormality has occurred in the state of the monitoring target Can be determined.

  DESCRIPTION OF SYMBOLS 10 Sensor controller, 11 1st degradation diagnostic part, 12 2nd degradation diagnostic part, 20 Sensor head, 21 Sensor part, 22 Acceleration information output part, 30 Mounting base.

Claims (3)

A sensor controller for diagnosing whether or not the mounting state of the structure is normal based on acceleration information of the structure output from a sensor head installed on a structure that is attached to a fixed surface and is subject to deterioration diagnosis And at least one of the tilt information and the natural frequency information of the structure is extracted as a feature amount based on the acceleration information acquired from the sensor head, and the reference probability in a normal state with respect to the extracted feature amount A structure deterioration that calculates a density distribution and a probability density distribution for diagnosis at the time of deterioration diagnosis, and diagnoses deterioration of the mounting state of the structure based on a comparison between the probability density distribution for reference and the probability density distribution for diagnosis A sensor head mounting base used in a diagnostic system,
A sensor mounting base formed as a single plate on which two sensor heads can be installed on the same plane. A sensor controller for diagnosing whether or not the mounting state of the structure is normal based on acceleration information of the structure output from a sensor head installed on a structure that is attached to a fixed surface and is subject to deterioration diagnosis In the structure deterioration diagnosis system provided, the structure deterioration diagnosis system executed by the sensor controller,
Feature amount extraction means for extracting at least one of the tilt information and the natural frequency information of the structure as the feature amount based on the acceleration information acquired from the sensor head;
When the reference data obtained in the normal state and the diagnostic data obtained at the time of deterioration diagnosis have a significant difference of a predetermined amount or more based on the feature quantity extracted by the feature quantity extraction unit, the structure Determining means for determining that an abnormality has occurred in the mounting state of
Adopting the mounting base according to claim 1 as the fixed surface,
An existing sensor and a new sensor installed in parallel with the existing sensor to replace the existing sensor are installed on the mounting base as the two sensors,
The feature amount extraction unit individually obtains inclination information or natural frequency information for the existing sensor head and each of the new sensor heads installed together with the existing sensor head in order to replace the existing sensor head. Extract and
In order to correct the deviation between the mounting direction of the existing sensor head and the mounting direction of the new sensor head and make the coordinate axes coincide with each other, the tilt information extracted for the new sensor head is used as the tilt extracted for the existing sensor head. Further comprising error correction means for calculating a transformation matrix for matching the natural frequency information extracted for the new sensor head with the natural frequency information extracted for the existing sensor head.
The feature amount extraction unit can convert acceleration information acquired from the new sensor head into acceleration information corresponding to the case where the existing sensor head is used by using the conversion matrix,
The determination means converts the reference data obtained based on the feature value extracted by the existing sensor head into reference data corresponding to the case of using the new sensor head by using an inverse matrix of the conversion matrix. Can
The structure deterioration diagnosis system that can continue to use the reference data accumulated based on the existing sensor head and a significant difference of the predetermined amount or more used for deterioration determination even after the existing sensor head is removed. A sensor controller for diagnosing whether or not the mounting state of the structure is normal based on acceleration information of the structure output from a sensor head installed on a structure that is attached to a fixed surface and is subject to deterioration diagnosis In the structure deterioration diagnosis system provided, the structure deterioration diagnosis system executed by the sensor controller,
Feature amount extraction means for extracting at least one of the tilt information and the natural frequency information of the structure as the feature amount based on the acceleration information acquired from the sensor head;
When the reference data obtained in the normal state and the diagnostic data obtained at the time of deterioration diagnosis have a significant difference of a predetermined amount or more based on the feature quantity extracted by the feature quantity extraction unit, the structure Determining means for determining that an abnormality has occurred in the mounting state of
Adopting the mounting base according to claim 1 as the fixed surface,
The sensor before replacement and the current sensor are installed on the mounting base,
In order to make the coordinate axes coincide with each other by correcting a deviation between the current sensor head mounting direction and the reference mounting direction, the tilt information extracted for the current sensor head is matched with reference tilt information defined in advance. Or an error correction means for calculating a conversion matrix for matching the natural frequency information extracted for the current sensor head with a predetermined reference natural frequency information every time the sensor head is replaced. ,
The feature amount extraction unit converts the acceleration information acquired from the current sensor head into normalized acceleration information normalized so as to correspond to the reference mounting direction by using the conversion matrix, and Extract normalized features based on normalized acceleration information,
The determination means is based on the normalized feature amount extracted by the feature amount extraction means, and the attachment state of the structure is compared with reference data obtained in a normal state and diagnosis data obtained at the time of deterioration diagnosis. To determine whether an abnormality has occurred
A structure deterioration diagnosis system in which the reference data accumulated based on the sensor head before replacement and the significant difference of the predetermined amount or more used for deterioration determination can be continuously used even after the sensor head is replaced.

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