JP2006010520A - Seismoscope and seismometer system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide high-reliability seismoscope and seismometer capable of surely detecting a failure of an acceleration sensor. <P>SOLUTION: The seismoscope 2 is provided with acceleration sensors 21 to 24. The measuring axis direction vectors 21a to 24a of the acceleration sensors 21 to 24 are set to be nearly the same angle with each other. If an acceleration is added to the seismoscope 2, each acceleration sensor 21 to 24 detects acceleration component in accordance with the measuring axis directions 21a to 24a. By arranging the acceleration sensors 21 to 24 in this manner, vector sum of each acceleration component always becomes below a constant value for omnidirectional acceleration. In the case that any of the acceleration sensors fails, this law is not formed and the vector sum of each acceleration component exceeds a constant value. Therefore, a failure of the acceleration sensors 21 to 24 can be surely detected. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a seismic device including an acceleration sensor for measuring three-dimensional acceleration, and a seismometer system including the seismic device.

  Conventionally, a three-dimensional acceleration sensor is arranged in accordance with a coordinate axis of a three-dimensional orthogonal coordinate system, for example, in a seismic instrument for measuring three-dimensional acceleration. Based on the acceleration signals from the three acceleration sensors, the acceleration vector due to the earthquake is calculated, and the seismic intensity, maximum acceleration, various response values, SI value, and the like are calculated.

In addition, as a prior art relevant to this invention, there exists the patent document shown below.
Japanese Patent No. 3376476

  In recent years, systems have been developed for emergency stop of public transportation or plant facilities depending on the intensity of earthquakes observed. In such a system, the seismic device is required to have extremely high reliability because erroneous earthquake information due to the failure of the seismic device causes great economic damage.

  In the conventional seismoscope as described above, even if one of the three acceleration sensors fails, the operation continues without being recognized. For this reason, there is a possibility that the seismic intensity and the like may be calculated using erroneous data resulting from the failure of the acceleration sensor. On the other hand, for example, a test signal is sent to each acceleration sensor and a response is checked to detect a failure, or an acceleration sensor different from the three acceleration sensors is provided. A method of detecting a failure by comparing the output from the acceleration sensor can be considered. However, in these methods in which a device for detecting a failure is provided separately from the acceleration sensor, the failure detection device itself may break down. Therefore, extremely high reliability for emergency stop of public transportation It is difficult to satisfy.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a highly reliable seismometer and seismometer system capable of reliably detecting a failure of an acceleration sensor.

  In order to solve the above-described problem, a first seismoscope according to the present invention is a seismoscope for measuring acceleration due to an earthquake, and includes four acceleration sensors for measuring acceleration components in different measurement axis directions. And a support that supports the four acceleration sensors, and the support holds the measurement axis directions of the four acceleration sensors so that the acceleration component vectors in the measurement axis directions of the four acceleration sensors cancel each other. It is characterized by that. A second seismoscope according to the present invention is a seismoscope for measuring acceleration due to an earthquake, and includes four acceleration sensors for measuring acceleration components in different measurement axis directions, and four acceleration sensors. And supporting the four acceleration sensors so that the measurement axes of the four acceleration sensors are substantially equiangular with each other.

  When acceleration is applied to the first or second seismic device, each acceleration sensor detects an acceleration component along the respective measurement axis direction. In the first and second seismographs according to the present invention, the respective acceleration sensors are supported so that the acceleration component vectors cancel each other out or the measurement axis directions are substantially equiangular. Therefore, the vector sum of the acceleration component vectors measured in each acceleration sensor is theoretically a zero vector for accelerations in all directions. Even if the acceleration component vector includes an acceleration sensor mounting error, a measurement error, or the like, the absolute value of the vector sum of the acceleration component vectors is equal to or less than a predetermined threshold. If any of the acceleration sensors fails, this law is not satisfied, and the vector sum of each acceleration component exceeds a predetermined threshold value. Therefore, according to the first or second seismic sensor, a failure of the acceleration sensor can be reliably detected by obtaining the sum of the acceleration component vectors. Even if one acceleration sensor breaks down, it is possible to continue measuring three-dimensional acceleration with the remaining three acceleration sensors. From the above, according to the first or second seismic sensor, it is possible to reliably detect a failure of the acceleration sensor without providing a failure detection device separate from the acceleration sensor, and an extremely reliable seismic sensor. Can be provided.

  Further, the seismometer system according to the present invention includes any one of the above-described seismometers and a calculation unit that detects a failure of the acceleration sensor based on a vector sum of acceleration components measured by each of the four acceleration sensors. It is characterized by providing. Thereby, it is possible to realize a highly reliable seismometer system that can reliably and automatically detect a failure of the acceleration sensor.

  In the present invention, the “vector sum” is not limited to a simple sum of acceleration component vectors in each acceleration sensor. For example, after inverting an acceleration component vector in at least one speed sensor, the vector of each acceleration component It is a concept that includes the case of seeking the sum.

  The seismometer system may be characterized in that the calculation unit detects a failure of the acceleration sensor based on a magnitude relationship between a vector sum of acceleration components and a predetermined threshold value. As described above, according to the seismometer provided in this seismometer system, the absolute value of the vector sum of each acceleration component is always less than or equal to a certain value with respect to the acceleration in any direction. Therefore, according to this seismometer system, the failure of the acceleration sensor can be reliably detected based on the vector sum of the acceleration components.

  The seismometer system may be characterized in that the calculation unit calculates an acceleration component in the failed acceleration sensor based on an acceleration component in another normal acceleration sensor. Thereby, even when the acceleration sensor fails, earthquake-related information such as seismic intensity can be obtained, so that reliability can be further improved.

  The seismometer system may be characterized in that the arithmetic unit detects a failure of the acceleration sensor by monitoring a gravitational acceleration component measured by each of the four acceleration sensors. Since a constant gravitational acceleration is always applied to each acceleration sensor, the failure of each acceleration sensor can be detected even during an earthquake by constantly monitoring the component of this acceleration in each acceleration sensor. Therefore, the reliability of the seismometer system can be further increased. Also, with this configuration, it is possible to easily know whether the seismic device is installed horizontally.

  In the seismometer system, the calculation unit switches the connection state / non-connection state of the wiring for the acceleration sensor to output an acceleration signal indicating the magnitude of the acceleration component based on the detection result of the failure of the acceleration sensor. This may be a feature. As a result, the failed acceleration sensor can be repaired and replaced while the seismometer system is in operation.

  The seismometer system according to the present invention includes any one of the above-described seismic instruments and a storage unit that stores acceleration signals from four acceleration sensors. According to this seismometer system, the acceleration signal stored in the storage unit can be verified afterwards, so that an erroneous acceleration signal due to a failure of the acceleration sensor can be reliably identified without the above-described calculation unit. it can. Moreover, according to this seismometer system, it is possible to calculate the earthquake related information by excluding the acceleration signal of the failed acceleration sensor. As a result, an extremely reliable seismometer system can be provided. Examples of the earthquake-related information include seismic intensity, maximum acceleration, speed, and displacement, acceleration response of an object having a natural period, speed response, displacement response, and SI value.

  In addition, a seismometer system according to the present invention includes any one of the above-described seismometers and an output terminal for providing acceleration signals from four acceleration sensors to a host system. According to this seismometer system, reliable failure information of the acceleration sensor can be recognized by the host system, so that an erroneous acceleration signal due to the failure of the acceleration sensor can be surely eliminated by the host system. As a result, an extremely reliable seismometer system can be provided. Examples of the host system include an earthquake observation system installed at a local weather station or a local government office.

  The seismometer system may further include a related information calculation unit that calculates earthquake related information based on acceleration signals from at least three of the four acceleration sensors. Thereby, highly reliable earthquake-related information can be easily obtained.

  Further, the seismometer system is a three-dimensional orthogonal coordinate system for specifying earthquake-related information, and the measurement axis directions of two acceleration sensors out of four acceleration sensors are in a plane composed of two axes of the three-dimensional orthogonal coordinate system. And the seismic device is arranged so that the measurement axis direction of one of the two acceleration sensors is along one of the two axes of the three-dimensional orthogonal coordinate system. It may be a feature. By arranging the seismic instruments in this way, the installation conditions of the seismic instruments can be unified throughout the seismometer system, and the calculation conditions for earthquake-related information provided from this seismometer system can be unified. . In addition, by arranging the seismic sensor in this way, when calculating earthquake-related information based on a three-dimensional orthogonal coordinate system using each acceleration component, the earthquake-related information is obtained by a relatively simple arithmetic expression. Can do.

  ADVANTAGE OF THE INVENTION According to this invention, the highly reliable seismometer and seismometer system which can detect the failure of an acceleration sensor reliably can be provided.

  Embodiments of a seismic instrument and a seismometer system according to the present invention will be described below in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a block diagram showing the configuration of the seismometer system 1 according to the first embodiment of the present invention. Referring to FIG. 1, the seismometer system 1 includes a seismic instrument 2, a calculation unit 3, a related information calculation unit 5, a storage unit 7, and a sensor test unit 8. The calculation unit 3 includes a failure detection unit 30, a monitoring unit 35, a switching unit 40, and an addition inversion unit (described later). The calculation unit 3, the related information calculation unit 5, and the sensor test unit 8 may be realized by an electronic circuit, or may be realized by a computer that operates according to a program stored in advance.

  The seismoscope 2 has four acceleration sensors 21 to 24. For example, servo type acceleration sensors may be used as the acceleration sensors 21 to 24. Specifically, the acceleration sensors 21 to 24 first detect the displacement of the mass-spring weight due to the acceleration, and act on the weight by a drive system composed of a magnet and a coil through the servo system, thereby restoring the weight displacement. The acceleration can be obtained based on the current value required to return to the position.

  Here, Fig.2 (a) is a top view of the seismic device 2 of this embodiment. Moreover, FIG.2 (b) is a side view of the seismic device 2, and FIG.2 (c) is sectional drawing which shows the II cross section of the seismic device 2 shown to Fig.2 (a). Referring to FIGS. 2A to 2C, the seismic sensor 2 includes four acceleration sensors 21 to 24 and a support body 25 that supports the acceleration sensors 21 to 24.

  The support body 25 includes a bottom plate 25a, side plates 25b to 25d, and a top plate 25e. The bottom plate 25a has a substantially equilateral triangular shape, and the acceleration sensor 21 is placed in the center portion on the bottom plate 25a. The measurement axis direction vector 21a of the acceleration sensor 21 is perpendicular to the surface of the bottom plate 25a. When the seismoscope 2 is installed at the measurement location, the bottom plate 25a is horizontally arranged so as to intersect perpendicularly to the vertical direction. Therefore, the acceleration sensor 21 is arranged so that the measurement axis 21a of the acceleration sensor 21 is along the vertical direction. With such an arrangement, the acceleration sensor 21 measures the acceleration component along the vertical direction of the acceleration vector applied to the seismic sensor 2.

  The side plates 25b to 25d are fixed to the bottom plate 25a so that the lower side is along the corresponding side of the bottom plate 25a. In addition, the side plates 25b to 25d are fixed to be inclined with respect to the bottom plate 25a, and respectively constitute a part of a side surface of a regular tetrahedron assumed with the bottom plate 25a as a bottom surface. Further, acceleration sensors 22 to 24 are mounted on the side plates 25b to 25d, respectively. Accordingly, the measurement axis direction vectors 21a to 24a of the acceleration sensors 21 to 24 are substantially equiangular (109.28 °). The top plate 25e fixes the upper sides of the side plates 25b to 25d to each other in order to maintain the mechanical strength of the side plates 25b to 25d. Further, from each of the acceleration sensors 21 to 24, wirings 26 a to 26 d for providing an acceleration signal indicating the magnitude of the measured acceleration component to the calculation unit 3 and the storage unit 7 extend to the outside of the seismic instrument 2. .

  FIG. 3A and FIG. 3B are diagrams for explaining in detail the directions of the measurement axis direction vectors 21a to 24a of the acceleration sensors 21 to 24. FIG. Fig.3 (a) is a perspective view which shows the relative relationship of the measurement-axis direction vectors 21a-24a. FIG. 3B is a plan view of the relative relationship between the measurement axis direction vectors 21a to 24a as viewed from above. 3A and 3B, the directions of the measurement axis direction vectors 21a to 24a indicate the positive direction of the acceleration component. 3A and 3B, the ud axis indicates the vertical direction, the ew axis indicates the east-west direction, and the ns axis indicates the north-south direction. Generally, the axes of a three-dimensional orthogonal coordinate system for specifying earthquake-related information are set to coincide with the ud axis, the ew axis, and the ns axis.

The measurement axis direction vectors 21a to 24a are set so that the acceleration component vectors in the measurement axis directions cancel each other. Specifically, each measurement axis direction vector 21a to 24a is set in a symmetric direction in space so as to substantially coincide with a vector from the center of gravity of the regular tetrahedron to each vertex. In the present embodiment, the angle θ ₁₂ formed by the measurement axis direction vector 21a and the measurement axis direction vector 22a, the angle θ ₁₃ formed by the measurement axis direction vector 21a and the measurement axis direction vector 23a, the measurement axis direction vector 21a and the measurement axis direction. An angle θ ₁₄ formed by the vector 24a, an angle θ ₂₃ formed by the measurement axis direction vector 22a and the measurement axis direction vector 23a, an angle θ ₃₄ formed by the measurement axis direction vector 23a and the measurement axis direction vector 24a, and a measurement axis direction vector 24a the angle theta ₂₄ of the measuring axis direction vector 22a is set to an angle approximately equal to each other. By setting the measurement axis direction vectors 21a to 24a of the acceleration sensors 21 to 24 in this way, the vector sum of the acceleration component vectors on the respective measurement axes of the acceleration sensors 21 to 24 is set regardless of whether or not earthquake motion occurs. In theory, it is always a zero vector. An acceleration sensor abnormality in a seismoscope occurs at various timings, such as when calm, at the beginning of an earthquake, or when a ground motion exceeds a certain intensity. In the seismoscope 2 according to the present invention, at any timing, if the vector sum of the acceleration component vectors deviates from the zero vector, it can be understood that at least the seismoscope 2 is abnormal. Actually, since there is an attachment error of the acceleration sensors 21 to 24 and an accuracy error of the support portion 25, strictly speaking, the vector sum is not a zero vector, but the absolute value of the vector sum is set to a certain fixed value or less. can do.

  In the three-dimensional orthogonal coordinate system (in this embodiment, the ud axis, ns axis, and ew axis) for specifying earthquake-related information, the measurement axes of two acceleration sensors out of the four acceleration sensors 21 to 24 are tertiary. Along the plane composed of two axes of the original Cartesian coordinate system, the measurement axis of one of the two acceleration sensors is set to one of the two axes of the three-dimensional Cartesian coordinate system. It is preferable that the seismic device 2 is arranged so as to be along. In the present embodiment, among the acceleration sensors 21 to 24, the measurement axis direction vectors 21a and 22a of the acceleration sensors 21 and 22 are along the plane composed of the ud axis and the ns axis of the three-dimensional orthogonal coordinate system, and the measurement of the acceleration sensor 21 is performed. The seismic sensor 2 is arranged so that the axial direction vector 21a is along the ud axis of the three-dimensional orthogonal coordinate system. The acceleration sensors 23 and 24 are arranged such that a difference vector between the measurement axis direction vector 23a and the measurement axis direction vector 24a is along the ew axis.

  FIG. 4 is a block diagram illustrating a configuration of the failure detection unit 30 included in the calculation unit 3. Referring to FIG. 4, the failure detection unit 30 includes an abnormality detection unit 31, a low-pass filter (LPF) abnormality detection unit 32, a high-pass filter (HPF) abnormality detection unit 33, and a band abnormality detection unit 34. . As described above, the abnormality of the acceleration sensor occurs at various timings such as when calm, at the beginning of an earthquake, or when an earthquake motion exceeds a certain intensity. The failure detection unit 30 can detect an abnormality in the acceleration sensor at any timing when at least the vector sum of the acceleration component vectors in each of the acceleration sensors 21 to 24 deviates from the zero vector. Each component of the failure detection unit 30 described below detects in detail the occurrence of abnormality in each of the acceleration sensors 21 to 24 and the form of the occurrence, and generates various signals for coping with the abnormality of the acceleration sensor.

The abnormality detection unit 31 is a means for detecting a failure of the acceleration sensor that is mainly accompanied by a system abnormality or a large failure. The abnormality detection unit 31 calculates the vector sum of the acceleration components indicated by the acceleration signals S _{1 to} S ₄ from the respective acceleration sensors 21 to 24, and determines the magnitude of the vector sum and a predetermined threshold value, thereby causing a failure of the acceleration sensor. Is detected. Specifically, the abnormality detection unit 31 includes a sensor abnormality determination unit 31a. Sensor abnormality determination unit 31a inputs an acceleration signal _S 1 to S ₄ from the acceleration sensors 21 to 24, calculates the vector sum of the acceleration component based on these acceleration signals _S 1 to S _4. When the absolute value of the vector sum is larger than the predetermined threshold, the sensor abnormality determination unit 31a determines that at least one acceleration sensor among the acceleration sensors 21 to 24 has failed, and determines that the system is abnormal. Alternatively, when the acceleration signal from one of the acceleration sensors 21 to 24 does not reach the acceleration sensor 21 to 24 in a calm state, the vector sum obtained is compared with the actually obtained vector sum to obtain a faulty acceleration sensor. Can also be specified. Sensor abnormality determination unit 31a, a fault signal S ₁₁ that a failure of the acceleration sensor to identify an acceleration sensor failed with indicating occurrence, to the host system via the output end 1b of the seismometer system 1 (see FIG. 1) Output. The sensor abnormality determination unit 31a outputs a fault signal S ₁₅ corresponding to the acceleration sensor fails to switch unit 40.

The LPF abnormality detection unit 32 is a means for mainly detecting an offset abnormality and identifying a faulty acceleration sensor. Here, the offset refers to a value that is constantly included in the acceleration component values indicated by the acceleration signals S _{1 to} S ₄ from the acceleration sensors 21 to 24. For example, the acceleration signal S when the actual acceleration component value is zero. a certain offset value is output as ₁ to S _4. The offset abnormality is a phenomenon in which the offset of each acceleration sensor 21 to 24 adjusted at the initial setting of the seismometer system 1 exceeds a predetermined value due to some abnormality. The LPF abnormality detection unit 32 removes a high frequency component included in the acceleration components indicated by the acceleration signals S _{1 to} S ₄ and mainly detects an offset abnormality of the acceleration sensors 21 to 24 based on the low frequency component. Further, the LPF abnormality detection unit 32 identifies a failed acceleration sensor based on the low frequency component.

Specifically, the LPF abnormality detection unit 32 includes a low-pass filter (LPF) 32a and an offset abnormality determination unit 32b. LPF32a performs filtering on the acceleration components indicated by the acceleration signal S ₁ to S ₄ from the acceleration sensors 21 to 24, a means for extracting a low frequency component of the lower-band than the predetermined frequency. The LPF 32a provides a low frequency component extracted from the acceleration component in each of the acceleration sensors 21 to 24 to the offset abnormality determination unit 32b.

The offset abnormality determination unit 32b is means for determining an offset abnormality of each acceleration sensor 21 to 24 based on the low frequency component received from the LPF 32a. That is, the offset abnormality determination unit 32b calculates the vector sum of each low frequency component extracted from the acceleration component in each of the acceleration sensors 21 to 24, and compares the absolute value of the vector sum with a predetermined threshold value. The offset abnormality determination unit 32b determines that at least one of the acceleration sensors 21 to 24 is an offset abnormality when the vector sum of the low frequency components is larger than a predetermined threshold, and identifies the abnormality sensor. Offset abnormality determination unit 32b, it outputs a failure signal S ₁₂ to identify the faulty sensor with indicating that offset error occurs in the acceleration sensor, the host system via the output end 1b of the seismometer system 1 (see FIG. 1) To do. Further, the offset abnormality determination unit 32b outputs a fault signal S ₁₆ corresponding to the acceleration sensor fails to switch unit 40.

The HPF abnormality detection unit 33 is a means for mainly detecting a transient operation abnormality and specifying a faulty acceleration sensor. Here, originally, the acceleration signals S _{1 to} S ₄ from the acceleration sensors 21 to 24 operate smoothly (transiently) according to the acceleration applied to the acceleration sensors 21 to 24. The transient operation abnormality refers to a phenomenon in which the acceleration signals S _{1 to} S ₄ from the acceleration sensors 21 to 24 do not operate smoothly according to the acceleration but perform a stepwise operation. The HPF abnormality detection unit 33 removes a low frequency component included in the acceleration components indicated by the acceleration signals S _{1 to} S ₄ and mainly detects a transient operation abnormality of the acceleration sensors 21 to 24 based on the high frequency component. Further, the HPF abnormality detection unit 33 identifies the failed acceleration sensor based on the high frequency component.

Specifically, the HPF abnormality detection unit 33 includes a high-pass filter (HPF) 33a and a transient operation abnormality determination unit 33b. HPF33a performs filtering on the acceleration components indicated by the acceleration signal S ₁ to S ₄ from the acceleration sensors 21 to 24, a means for extracting a high frequency component of the higher-band than the predetermined frequency. The HPF 33a provides the high-frequency component extracted from the acceleration component in each of the acceleration sensors 21 to 24 to the transient operation abnormality determining unit 33b.

The transient operation abnormality determination unit 33b is means for determining a transient operation abnormality of each of the acceleration sensors 21 to 24 based on the high frequency component received from the HPF 33a. That is, the transient operation abnormality determination unit 33b calculates the vector sum of each of the high frequency components extracted from the acceleration components in the respective acceleration sensors 21 to 24, and compares the absolute value of the vector sum with the predetermined threshold value. The transient operation abnormality determining unit 33b determines that at least one acceleration sensor among the acceleration sensors 21 to 24 is a transient operation abnormality when the vector sum of the high frequency components is larger than a predetermined threshold. Further, depending on the failure state of the acceleration sensors 21 to 24, when the filtering process is performed, the acceleration signal value may become excessive, and thus the abnormal sensor can be specified. Transient operation abnormality determination unit 33b, the host system via a fault signal S ₁₃ that the faulty sensors for identifying the output terminal 1b of the seismometer system 1 (see FIG. 1) with indicating that transient operation abnormality in the acceleration sensor occurs Output to. Furthermore, transient operational abnormality determination unit 33b outputs a fault signal S ₁₇ corresponding to the acceleration sensor fails to switch unit 40.

The band abnormality detection unit 34 is a means for detecting an abnormality of the acceleration component indicated by the acceleration signals S _{1 to} S ₄ for each frequency component. The band abnormality detection unit 34 detects the abnormality of each acceleration component for each predetermined frequency component after converting the acceleration signals S _{1 to} S ₄ into signals in the frequency domain. Further, the band abnormality detection unit 34 identifies a failed acceleration sensor based on the detected abnormal frequency component.

Specifically, the band abnormality detection unit 34 includes a fast Fourier transform unit (FFT) 34a, a band abnormality determination unit 34b, and an inverse Fourier transform unit (Reverse Fourier Transformer: RFT) 34c. FFT34a is a means for converting the acceleration signal _S 1 to S ₄ from the acceleration sensors 21 to 24 into a frequency domain signal. The FFT 34a provides a frequency domain signal converted from the acceleration component in each of the acceleration sensors 21 to 24 to the band abnormality determination unit 34b.

The band abnormality determination unit 34b is a means for determining the abnormality of the acceleration signals S _{1 to} S ₄ for each frequency band based on the frequency domain data received from the FFT 34a. That is, the band abnormality determination unit 34b is the vector sum of the converted frequency domain signals from the acceleration signal S ₁ to S ₄ of the acceleration sensors 21 to 24 is calculated for each predetermined frequency component, and the absolute value of the vector sum The magnitude is compared with a predetermined threshold value. At this time, the predetermined threshold value may be determined for each frequency component. The band abnormality determination unit 34b determines that an acceleration signal in the frequency band of at least one of the acceleration sensors 21 to 24 is abnormal when the vector sum of a certain frequency component is larger than a predetermined threshold value in the frequency component. Determine and identify the abnormal sensor. Band abnormality determination unit 34b is a fault signal S ₁₄ to identify the faulty sensor with indicating that abnormality in a certain frequency component of the acceleration signal is generated via the output end 1b of the seismometer system 1 (see FIG. 1) higher Output to the system. Further, the band abnormality determination unit 34b outputs a fault signal S ₁₈ corresponding to the acceleration sensor fails to switch unit 40. Further, the band abnormality determining unit 34b performs mask processing on a band including a frequency component having an abnormality in the frequency domain signal, and outputs the frequency domain signal to the RFT 34c.

The RFT 34c is means for performing an inverse Fourier transform on the frequency domain signal from the band abnormality determining unit 34b. The frequency domain signal input by the RFT 34c is subjected to mask processing in an abnormal frequency band by the band abnormality determination unit 34b described above. Therefore, when the frequency domain signal is subjected to inverse Fourier transform, time-series acceleration signals S _{21 to} S ₂₄ from which abnormal frequency components are removed are generated. The RFT 34 c outputs the generated acceleration signals S _{21 to} S ₂₄ to the switching unit 40.

  FIG. 5 is a block diagram illustrating the configuration of the addition inversion units 11 to 14 and the switching unit 40 included in the calculation unit 3. The addition inversion units 11 to 14 calculate and supplement the acceleration components in the failed acceleration sensor based on the acceleration components indicated by the three acceleration signals excluding the acceleration signals in the failed acceleration sensor among the acceleration sensors 21 to 24. It is means of. In this embodiment, since the measurement axes of the acceleration sensors 21 to 24 are set in the directions shown in FIGS. 3A and 3B, the three acceleration sensors other than the failed acceleration sensor are used. By adding and inverting the acceleration signal, it is possible to calculate the acceleration component in the failed acceleration sensor.

Specifically, the addition inversion unit 11 inputs acceleration signals S _{2 to} S ₄ from the acceleration sensors 22 to 24. If the acceleration component vectors indicated by the acceleration signals S _{2 to} S ₄ are a _{2 to} a ₄ , the addition inversion unit 11 calculates − (a ₂ + a ₃ + a ₄ ). Adding the inversion unit 11 outputs to the switching unit 40 the operation result as the complementary signal _{S 31.} Similarly, the addition inversion unit 12 inputs acceleration signals S ₁ , S ₃ , and S ₄ from the acceleration sensors 21, 23, and 24. Then, assuming that the acceleration component vector indicated by the acceleration signal S ₁ is a ₁ , the addition inversion unit 12 calculates − (a ₁ + a ₃ + a ₄ ), and outputs the calculation result to the switching unit 40 as a complementary signal S _32. . The addition reversing unit 13 inputs acceleration signals S ₁ , S ₂ , and S ₄ from the acceleration sensors 21, 22, and 24. Then, the addition inversion unit 13 calculates − (a ₁ + a ₂ + a ₄ ), and outputs the calculation result to the switching unit 40 as the complementary signal S ₃₃ . The addition reversing unit 14 inputs acceleration signals S _{1 to} S ₃ from the acceleration sensors 21 to 23. Then, the addition inversion unit 14 calculates − (a ₁ + a ₂ + a ₃ ), and outputs the calculation result to the switching unit 40 as the complementary signal S ₃₄ .

The switching unit 40 is means for switching the connection state / non-connection state of wiring for the acceleration sensors 21 to 24 to output the acceleration signals S _{1 to} S ₄ based on the failure detection result in the failure detection unit 30. . The switching unit 40 includes switch means SW1 to SW12. The switch means SW1 to SW12 are preferably switches that can be electrically insulated, such as mechanical switches, for example, but electrical switches such as transistors may be used.

One ends of the switch means SW1 to SW3 are electrically connected to each other and are connected to the related information calculation unit 5. The other end of the switch means SW1 is electrically connected to the acceleration sensor 21, receives an acceleration signal S _1. As shown in FIG. 5, an A / D converter 15 may be provided between the switch means SW <b> 1 and the acceleration sensor 21. This A / D converter 15 may provide acceleration signals S ₁ on which is converted from an analog signal to a digital signal, the acceleration signals S ₁ to the associated information calculating unit 5 through the switch means SW1. Further, the other end of the switch means SW2 is electrically connected to the addition inversion unit 11. The other end of the switch means SW2, the complementary signal S ₃₁ obtained by vectorially summing-inverting three acceleration signals except the acceleration signals S ₁ from the acceleration sensor 21 is input from the adder inverting unit 11. The other end of the switch means SW3 is electrically connected to the band abnormality detection unit 34 of the failure detection unit 30. The other end of the switch means SW3, acceleration signal S ₂₁ that is masked an abnormal frequency band is inputted from the band abnormality detection unit 34.

Switching unit 40, based on the failure signal _{S 53} inputted from the sensor test section 8 a fault signal _S 15 _{to S 18,} and will be described later input from the failure detecting unit 30, one of the switches of the switch means SW1~SW3 The means is connected and the other switch means is disconnected. That is, when none of the fault signal _S 15 _{to S 18} and _{S 53} are not input, the switching means SW1 and the connected state, the switch means SW2 and SW3 disconnected. When any one of the failure signals S _{15 to} S ₁₇ and S ₅₃ is input and this failure signal indicates a failure of the acceleration sensor 21, the switch means SW1 and SW3 are disconnected and the switch means SW2 Is connected. Furthermore, by entering the fault signal _{S 18,} when a failure signal _{S 18} indicates the abnormality of the acceleration signals _{S 1} from the acceleration sensor 21, the switch means SW1 and SW2 and disconnected, the connection state of the switch means SW3 To do.

The configuration and operation of the switch means SW4 to SW12 are the same as the switch means SW1 to SW3. That is, one end of the switch means SW4 to SW6, one end of the switch means SW7 to SW9, and one end of the switch means SW10 to SW12 are electrically connected to each other and connected to the related information calculation unit 5. The other end of the switch means SW4, SW7, and SW10 are respectively the acceleration sensor 22 to 24 are electrically connected, receiving the acceleration signal _S 2 to S _4. As shown in FIG. 5, an A / D converter 15 may be provided between the switch means SW4, SW7, and SW10 and the acceleration sensors 22-24. The other ends of the switch means SW5, SW8, and SW11 are electrically connected to the addition / inversion units 12 to 14, respectively. Complement signals S _{32 to} S ₃₄ are input from the addition / inversion units 12 to 14 to the other ends of the switch means SW 5, SW 8, and SW 11, respectively. The other ends of the switch means SW6, SW9, and SW12 are electrically connected to the band abnormality detection unit 34 of the failure detection unit 30. Acceleration signals S _{22 to} S ₂₄ are input from the band abnormality detection unit 34 to the other ends of the switch means SW6, SW9, and SW12.

Based on the failure signals S _{15 to} S ₁₈ input from the failure detection unit 30 and the failure signal S ₅₃ input from the sensor test unit 8 to be described later, the switching unit 40 combines the switch means SW4 to SW6 and switches SW7 to SW7. In each of the combination of SW9 and the combination of the switch means SW10 to SW12, any one switch means is set in a connected state, and the other switch means is set in a non-connected state. That is, when none of the fault signal _S 15 _{to S 18} and _{S 53} are not input, the switching means SW4, SW7, and SW10 to the connection state, the switch unit SW5, SW6, SW8, SW9, SW11, and SW12 non Connected. When any one of the failure signals S _{15 to} S ₁₇ and S ₅₃ is input and this failure signal indicates a failure of any one of the acceleration sensors 22 to 24, the switch means SW5 and SW8. , SW11 corresponding to the failed acceleration sensor is set to the connected state, and among the switch means SW4, SW7, SW10, the switch means corresponding to the failed acceleration sensor is set to the disconnected state. Furthermore, by entering the fault signal _{S 18,} when a failure signal _{S 18} indicates an abnormality in one of the acceleration signal of the acceleration sensor 22 to 24, corresponding to abnormal acceleration signal of the switching means SW6, SW9, SW12 The switch means to be connected is set to the connected state, and the switch means corresponding to the abnormal acceleration signal among the switch means SW4, SW7, SW10 is set to the disconnected state.

By the function of the switching unit 40, corresponding to each of the acceleration sensors 21 to 24, an acceleration signal _S 1 to S ₄ from the acceleration sensor 21 to 24, an acceleration signal _S 21 _{to S 24} from the band abnormality detection unit 34, Any one of the complementary signals S _{31 to} S ₃₄ from the addition / inversion units 11 to 14 is selected and output to the related information calculation unit 5 as acceleration signals S _{5 to} S ₈ . The switching of the switching means SW1~SW12 in the switching unit 40, in addition to the switching unit 4 is automatically performed, as described above, for example, the operator manually based on the fault signal _S 15 _{to S 18} and _{S 53} You may go.

Refer to FIG. 1 again. The monitoring unit 35 is a means for detecting a failure of the acceleration sensors 21 to 24 based on the gravitational acceleration component measured by the acceleration sensors 21 to 24. Gravitational acceleration is always applied to the acceleration sensors 21 to 24 other than during an earthquake, and gravitational acceleration components are always detected as the acceleration signals S _{1 to} S ₄ . The monitoring unit 35 inputs the acceleration signals S _{1 to} S ₄ from the acceleration sensors 21 to 24 except during an earthquake, and checks whether there is a significant change in the gravitational acceleration component in each of the acceleration signals S _{1 to} S ₄ . When the gravitational acceleration component in each of the acceleration signals S _{1 to} S ₄ is significantly changed, the monitoring unit 35 indicates a failure in the gravity value in the acceleration sensor and outputs a failure signal S ₁₉ that identifies the failure sensor. And output to the host system via the output terminal 1c.

Note that when the monitoring unit 35 checks the gravitational acceleration component in the acceleration signal S ₁ to S ₄ is preferably high-frequency components of the acceleration signal S ₁ to S ₄ are removed. Therefore, the monitoring unit 35 receives the acceleration signal _S 1 to S ₄ of the high-frequency component is removed from LPF32a failure detection unit 30, the gravitational acceleration component based on the acceleration signal _S 1 to S ₄ from LPF32a Check for changes. Further, by monitoring unit 35 monitors the gravitational acceleration component in the acceleration signal S ₁ to S _4, it is also possible to know the quality of the horizontal installation state of seismic sensor 2.

  FIG. 6 is a block diagram showing an internal configuration of the related information calculation unit 5. Referring to FIG. 6, the related information calculation unit 5 includes a waveform recording unit 51, a seismic intensity calculation unit 52, and a response value / SI value processing unit 53.

Waveform recording unit 51 generates the earthquake related information by performing a predetermined filtering process and arithmetic processing on the acceleration signal S ₅ to S ₈ input via the operation unit 3 from the acceleration sensors 21 to 24 And means for recording and printing the earthquake-related information on a recording medium such as paper in a predetermined format. Specifically, the waveform recording unit 51 includes a pre-processing unit 51a for generating a seismic relevant information performs predetermined filter processing and arithmetic processing and the like based on the acceleration signal S ₅ to S _8, is generated in the pre-processing unit 51a And a recording unit 51b for recording earthquake related information. Examples of the earthquake-related information recorded in the waveform recording unit 51 include waveform information (trigger time, installation information, acceleration waveform of seismic wave, etc.), one earthquake information (trigger time with 60 seconds as one earthquake, seismic intensity, measured seismic intensity, Maximum acceleration, etc.), section information (such as seismic intensity for each section with 10 seconds as one section, measured seismic intensity, maximum acceleration, etc.).

The seismic intensity calculation unit 52 is a means for calculating the measured seismic intensity based on the acceleration signals S _{5 to} S ₈ input from the respective acceleration sensors 21 to 24 via the calculation unit 3. The seismic intensity calculation unit 52 includes an HPF 52a, an FFT 52b, a seismic intensity calculation filter 52c, an RFT 52d, and a processing unit 52e. HPF52a cuts low frequency components such as offset of the acceleration signal S ₅ to S _8, a filter that passes high-frequency components including a frequency band of the seismic waves. The seismic intensity calculation unit 52 may also use the HPF 33a in the HPF abnormality detection unit 33 of the failure detection unit 30 instead of the HPF 52a.

FFT52b, seismic intensity calculation filter 52c, and RFT52d is means for extracting an acceleration signal in the frequency band of the seismic wave from the acceleration signal _S 5 to S _8. FFT52b a low frequency component of the acceleration signal _S 5 to S _8, which is cut, to convert the signal in the time domain into signal in the frequency domain by HPF52a. Seismic intensity calculation filter 52c cuts the components other than the frequency band of the seismic wave in the acceleration signal S ₅ to S _8, which is converted into a frequency domain signal. RFT52d is an acceleration signal S ₅ to S ₈ in which components other than the frequency band of the seismic wave is cut back from the signal of the frequency domain to the signal in the time domain. Processing unit 52e, the components other than the frequency band of the seismic waves based on an acceleration signal S ₅ to S ₈ in the time domain which is cut, a means for calculating a seismic intensity by vector synthesis. Processing unit 52e stores the calculated seismic intensity, as seismic information S ₉₁ is part of the earthquake related information S _9, is output from the output terminal 1a of the seismometer system 1 (see FIG. 1) to the host system.

と表すことができる。なお、数式中のｋ及びｍは、幾何的に求まる定数である。また、加速度の大きさａは、次式（４）

によって容易に求めることができる。なお、加速度ベクトルａ_ｕｄ、ａ_ｎｓ、及びａ_ｅｗ、並びに加速度の大きさａは、加速度センサ２１〜２４のうち１つの加速度センサが故障しても、残りの正常な加速度センサからの加速度信号に基づいて求めることができる。 When the processing unit 52e requires acceleration components in the directions of the respective axes (the ud axis, the ns axis, and the ew axis in FIG. 3) of the three-dimensional orthogonal coordinate system, the following equations (1) to (3) Can be easily obtained. That is, the acceleration component vector acceleration sensor 21 to 24 is measured with _a 1 ~a ₄ respectively, ud axis, ns axis, and ew-axis direction _a ud acceleration component vector _{of, a ns,} and _{a ew} and Then

It can be expressed as. Note that k and m in the formula are geometrically determined constants. The acceleration magnitude a is expressed by the following equation (4).

Can be easily obtained. Note that the acceleration vectors a _ud , a _ns , and a _ew , and the magnitude of the acceleration a are the acceleration signals from the remaining normal acceleration sensors even if one of the acceleration sensors 21 to 24 fails. Can be based on.

The response value / SI value processing unit 53 receives response values (applies to structures having a certain natural period) based on the acceleration signals S _{5 to} S ₈ input from the acceleration sensors 21 to 24 via the calculation unit 3. This is a means for calculating an acceleration response, velocity response, displacement response, etc.) and SI value. The response value / SI value processing unit 53 includes a preprocessing unit 53a, a speeding calculation unit 53b, a displacement calculation unit 53c, and a processing unit 53d. The preprocessing unit 53a performs predetermined filter processing, arithmetic processing, and the like. Speed of operation unit 53b calculates the velocity of ground motion based on the acceleration signal _S 5 to S _8. The displacement calculation part 53c calculates | requires the displacement of the ground based on the speed of the earthquake motion calculated | required by the speed calculation calculation part 53b. Processing unit 53d, the acceleration signal S ₅ to S _8, the speed of the ground motion determined by the speed of operation unit 53b, and based on the displacement of the ground obtained by the displacement of calculating unit 53c, calculates the response value and SI values To do. Processing unit 53d has a respective calculated response value and SI values, as a response value information _{S 92} and SI value information _{S 93} is part of the earthquake related information _{S 9,} the output terminal 1a of the seismometer system 1 (Fig. 1 To the higher system.

The related information calculation unit 5 further includes validity check units 54a to 54i. Validation unit 54a~54i, in each processing inside relevant information calculating section 5, or a new abnormality in the acceleration signal S ₅ to S ₈ are not generated (i.e., each element constituting the relevant information calculating section 5 Is a means for checking whether or not there is a failure. Validation unit 54a~54i calculates the vector sum of the acceleration component vector represented by the acceleration signal S ₅ to S _8, or comparison between the vector sum with a predetermined threshold, or the vector sum is zero vectors not By checking this, it is possible to find a failure of an element provided immediately before each of the validity check units 54a to 54i. In the present embodiment, the validity check unit 54 a is provided between the calculation unit 3, the waveform recording unit 51, the seismic intensity calculation unit 52, and the response value / SI value processing unit 53. The validity check unit 54b is provided between the preprocessing unit 51a and the recording unit 51b of the waveform recording unit 51. The validity check unit 54 c is provided between the HPF 52 a and the FFT 52 b of the seismic intensity calculation unit 52. The validity check unit 54d is provided between the FFT 52b of the seismic intensity calculation unit 52 and the seismic intensity calculation filter 52c. The validity check unit 54e is provided between the seismic intensity calculation filter 52c of the seismic intensity calculation unit 52 and the RFT 52d. The validity check unit 54f is provided between the RFT 52d of the seismic intensity calculation unit 52 and the processing unit 52e. The validity check unit 54g is provided between the preprocessing unit 53a of the response value / SI value processing unit 53 and the speed calculation unit 53b. The validity check unit 54 h is provided between the speed calculation unit 53 b and the displacement calculation unit 53 c of the response value / SI value processing unit 53. The validity check unit 54 i is provided between the displacement calculation unit 53 c and the processing unit 53 d of the response value / SI value processing unit 53.

  The related information calculation unit 5 may be realized by an analog or digital electronic circuit, or may be realized by a computer that operates according to a program stored in advance. When the related information calculation unit 5 is realized by a digital circuit or a computer, an A / D conversion unit 15 (see FIG. 5) may be provided between the related information calculation unit 5 and each of the acceleration sensors 21 to 24.

Refer to FIG. 1 again. The storage unit 7 is a means for storing the acceleration signals S _{1 to} S ₄ from the acceleration sensors 21 to 24. The storage unit 7 is realized by a storage element such as a memory, a storage device such as a hard disk, or a storage medium such as an optical disk. Storage unit 7 is electrically connected to the acceleration sensors 21 to 24, and inputs an acceleration signal _S 1 to S _4. The storage unit 7 may store the acceleration signals S _{1 to} S ₄ as they are, or may store a signal obtained by performing a predetermined process on the acceleration signals S _{1 to} S ₄ . The storage unit 7, it is preferable to store those subjected to the same processing for each of the four acceleration sensors 21 to 24 acceleration signal _S 1 to S _4. Also, be determined as a failure or the acceleration sensor 21 to 24 is in the fault detection section 30, it is preferable to directly store the acceleration signal S ₁ to S _4. By doing so, a favorable acceleration signal or its frequency component can be extracted from the acceleration signals with low reliability and used for seismic intensity calculation or the like. Further, by storing the acceleration signals S _{1 to} S ₄ in the storage unit 7, the acceleration signals S _{1 to} S ₄ can be verified afterwards. The acceleration signals S _{1 to} S ₄ are the signals output from the acceleration sensors 21 to 24 as they are, and the absolute value of the vector sum of the acceleration component vectors indicated by the acceleration signals S _{1 to} S ₄ is determined by the acceleration sensor failure. Otherwise, it will always be below a certain value. In other words, the point in time when the absolute value of the vector sum of the acceleration component vectors deviates from a certain value or less is the point in time when the seismometer 2 is abnormal, and even if the seismometer system 1 cannot operate normally due to strong ground motion, the memory is stored. If the data stored in the unit 7 remains, it is possible to determine the presence or absence of an abnormality in the seismic device 2 later. For example, if the acquired acceleration signals S _{1 to} S ₄ and their acquisition times are stored in the storage unit 7, the abnormality occurrence time in the seismoscope 2 can be known. Therefore, it can be said that the acceleration signals S _{1 to} S ₄ obtained at least by the abnormality occurrence time are based on high reliability. The storage unit 7 may be provided as a part of the calculation unit 3 or the related information calculation unit 5 or may be attached to the seismic device 2.

The sensor test unit 8 is a means for individually inspecting the acceleration sensors 21 to 24. Sensor test unit 8, the constant-current-pulse signal _{S 51} is applied to the test terminals of the respective acceleration sensors 21 to 24 (e.g., one end of the coil), and inputs the response signal _{S 52} from the acceleration sensors 21 to 24. Sensor test unit 8, when the response signal S ₅₂ of one of the acceleration sensors 21 to 24 is abnormal, and outputs a fault signal S ₅₃ indicating the failure of the acceleration sensor to the switching unit 40 of the arithmetic unit 3.

Further, seismometer system 1 includes an output terminal 1d for outputting an acceleration signal _S 1 to S ₄ from the acceleration sensors 21 to 24 to the host system. Seismometer system 1 outputs an acceleration signal _S 1 to S ₄ to the host system via the output terminal 1d. At this time, it is preferable that the seismometer system 1 further includes an A / D conversion unit for converting the acceleration signals S _{1 to} S ₄ that are analog signals into digital signals.

The seismometer system 1 includes the acceleration signals S _{1 to} S ₄ output from the acceleration sensors 21 to 24, the earthquake related information S ₉ output from the related information calculation unit 5, and the failure detection unit in addition to the above-described units. It is preferable to further include an interface unit (not shown) for outputting the failure signals S _{11 to} S ₁₄ output from the 30 and the failure signal S ₁₉ output from the monitoring unit to the host system. This interface unit is realized by, for example, a communication interface circuit. By providing such an interface unit, the seismometer system 1 can reliably provide each signal to a host system that comprehensively processes earthquake-related information from a plurality of seismometers.

Operation | movement of the seismometer system 1 provided with the above structure is demonstrated. First, each of the acceleration sensors 21 to 24 generates acceleration signals S _{1 to} S ₄ according to the acceleration of the ground. The acceleration signals S _{1 to} S ₄ are given to the failure detection unit 30, the monitoring unit 35, the switching unit 40, and the storage unit 7. The storage unit 7, an acceleration signal _S 1 to S ₄ are stored. Also, when a fault in the fault detection unit 30 and monitoring unit 35 is not detected, the acceleration signal S ₁ to S ₄ in the switching portion 40 is provided in the related information calculating section 5 as an acceleration signal S ₅ to S _8, relevant information calculation earthquake-related information S ₉ of seismic intensity and the like are calculated in part 5. Earthquake-related information S ₉ is output to the host system.

The acceleration signals S _{1 to} S ₄ are provided to the abnormality detection unit 31, the LPF abnormality detection unit 32, the HPF abnormality detection unit 33, and the band abnormality detection unit 34 in the failure detection unit 30. When at least one abnormality detection unit among these detects an abnormality in the acceleration signals S _{1 to} S ₄ , the failure detection unit 30 outputs the failure signals S _{11 to} S ₁₄ to the host system, and the failure signals S _{15 to} S _18. Is provided to the switching unit 40. The switching unit 40 generates a complementary signal from another normal acceleration sensor and provides the normal acceleration signal and the complementary signal to the related information calculation unit 5 when a failure other than a band abnormality is detected for the acceleration sensor in which the failure is detected. To do. In addition, even when a failure is detected in the sensor test unit 8, the switching unit 40 provides a normal acceleration signal and a complementary signal to the related information calculation unit 5. When at least one acceleration signal is abnormal in band, the switching unit 40 provides the related information calculation unit 5 with an acceleration signal obtained by masking the abnormal frequency band. Thus, seismometer system 1 can after a failure of the acceleration sensor is also calculated earthquake related information S _9.

The effect which the seismometer 2 and the seismometer system 1 demonstrated above have is demonstrated. The seismic device 2 of the present embodiment includes the four acceleration sensors 21 to 24 as described above so that the acceleration component vectors in the measurement axis directions 21a to 24a cancel each other or the measurement axis directions 21a to 24a. The acceleration sensors 21 to 24 are supported so that they are substantially equiangular. Therefore, the vector sum of the acceleration component vectors measured by the respective acceleration sensors 21 to 24 theoretically becomes a zero vector with respect to the acceleration in any direction. In reality, acceleration sensor mounting errors and measurement errors, electrical noise included in the acceleration signals S _{1 to} S _4, and the like are included in the acceleration component, but the absolute value of the vector sum of the acceleration components is always below a certain value. It becomes. If any of the acceleration sensors fails, this law is not satisfied, and the vector sum of each acceleration component exceeds a predetermined threshold value. Therefore, according to the seismic device 2 of the present embodiment, the failure of the acceleration sensors 21 to 24 can be reliably detected by obtaining the vector sum of the acceleration components. Even if one acceleration sensor breaks down, it is possible to continue measuring three-dimensional acceleration with the remaining three acceleration sensors. From the above, according to the seismic instrument 2 of the present embodiment, the reliability of the acceleration sensors 21 to 24 can be reliably detected without providing a failure detection device separate from the acceleration sensors 21 to 24. An extremely high seismic device can be provided.

  Further, in this way, in the seismic instrument 2, the absolute value of the vector sum of each acceleration component is always a certain value or less with respect to the acceleration in any direction. Therefore, it is preferable that the calculation unit 3 detects a failure of the acceleration sensors 21 to 24 based on the magnitude relationship between the vector sum of the acceleration components and the predetermined threshold in the failure detection unit 30 as in the present embodiment. Thereby, the highly reliable seismometer system 1 which can detect reliably and automatically the failure of the acceleration sensors 21-24 is realizable.

  Further, as in the present embodiment, the calculation unit 3 uses the addition inversion units 11 to 14 to convert the acceleration component of the acceleration sensor 21 to 24 out of the acceleration sensors to a failure based on the acceleration components of other normal acceleration sensors. It is preferable to calculate and complement. Thereby, even when any one of the acceleration sensors 21 to 24 fails, earthquake-related information such as seismic intensity can be obtained, so that the reliability can be further improved.

  Further, as in the present embodiment, the calculation unit 3 can detect a failure of the acceleration sensors 21 to 24 by monitoring the gravity acceleration components measured by the acceleration sensors 21 to 24 in the monitoring unit 35. preferable. Since a constant gravitational acceleration is constantly applied to each acceleration sensor 21 to 24, the failure of each acceleration sensor 21 to 24 can be detected during an earthquake by constantly monitoring the component of the gravitational acceleration in each acceleration sensor 21 to 24. It is possible to detect in other cases. Therefore, the reliability of the seismometer system 1 can be further improved. Further, as shown in FIG. 3A, the seismic device 2 is arranged so that the measurement axis direction 21a of the acceleration sensor 21 is along the ud axis (that is, the bottom plate 25a shown in FIG. 2 is horizontal). Since it is preferable to install, the quality of the horizontal installation state of the seismic device 2 can be easily known by monitoring the gravitational acceleration component measured by the acceleration sensors 21 to 24. When the acceleration sensor 21 to 24 monitors the gravitational acceleration component in this way, the gravitational acceleration component becomes zero when the measurement axis directions 21a to 24a of the acceleration sensors 21 to 24 are along the horizontal direction. The measurement axis directions 21a to 24a preferably form an angle larger than 0 ° with respect to the horizontal direction.

Further, as in the present embodiment, in the switching unit 40, the calculation unit 3 is connected to / disconnected from the wiring for the acceleration sensors 21 to 24 to output the acceleration signals S _{1 to} S ₄ to the related information calculation unit 5. state, it is preferable to switch on the basis of a fault signal _S 15 _{to S 18} and _{S 53.} As a result, the failed acceleration sensor can be repaired and replaced while the seismometer system 1 is in operation, leading to an improvement in the operating rate of the seismometer system 1.

Further, seismometer system 1 of this embodiment includes a storage unit 7 for storing the acceleration signal _S 1 to S ₄ from the acceleration sensor 21 to 24. As a result, the acceleration signals S _{1 to} S ₄ stored in the storage unit 7 can be verified afterwards, so even if the seismometer system 1 does not include the calculation unit 3, An erroneous acceleration signal can be reliably identified. Moreover, the earthquake-related information can be calculated by excluding the acceleration signal of the failed acceleration sensor. As a result, the extremely reliable seismometer system 1 can be provided.

Further, seismometer system 1 of this embodiment includes an output terminal 1d for providing an acceleration signal S ₁ to S ₄ of four acceleration sensors 21 to 24 to the host system. Thus, by checking the vector sum of the acceleration components in the host system, the reliable failure information of the acceleration sensors 21 to 24 can be recognized in the host system. Therefore, an erroneous acceleration signal due to a failure of the acceleration sensor can be reliably eliminated in the host system. As a result, the extremely reliable seismometer system 1 can be provided.

Also, as in the present embodiment, seismometer system 1 based on the acceleration signal from at least three acceleration sensors of the acceleration sensor 21 to 24, further relevant information calculation unit 5 for calculating a seismic related information S ₉ It is preferable to provide. This makes it possible to obtain a highly reliable earthquake related information S ₉ easily.

As in the present embodiment, in the seismometer system 1, the directions of the measurement axes 21 a and 22 a of the two acceleration sensors 21 and 22 among the acceleration sensors 21 to 24 are two axes (ud axis) of the three-dimensional orthogonal coordinate system. And the direction of the measurement axis 21a of one of the acceleration sensors 21 and 22 is set to one of the two axes (ud axis and ns axis) (ud axis). It is preferable that the seismic device 2 is arranged so as to be along. By arranging the seismic sensor 2 in this way, as shown in the mathematical expressions (1) to (3) described above, the amount of calculation for obtaining the acceleration vectors a _ud , a _ns , and a _ew is reduced. be able to. Further, as shown in the above formula (4), the acceleration magnitude a can also be obtained by simple calculation.

  Further, as in the present embodiment, the calculation unit 3 may detect an abnormal frequency component in the acceleration component based on the vector sum of the predetermined frequency components included in the acceleration component in the band abnormality detection unit 34. . In this case, a detailed failure analysis in the frequency domain can be performed for the failure of the acceleration sensors 21 to 24, and it becomes easy to specify the type of abnormality.

  Further, as in the present embodiment, the calculation unit 3 may remove (mask process) the abnormal frequency band component from the acceleration component in the band abnormality detection unit 34. When an abnormality is detected in a band different from the seismic frequency band, the acceleration signal in the seismic frequency band may be normal. Therefore, the operation rate of the acceleration sensors 21 to 24 can be improved by masking the band including the abnormal frequency component in the acceleration component in the band abnormality detection unit 34.

  The seismometer and seismometer system according to the present invention are not limited to the above-described embodiments, and various other modifications are possible. For example, the calculation unit and the related information calculation unit of the above embodiment are provided outside the seismoscope, but the calculation unit and the related information calculation unit may be provided inside the seismoscope. Alternatively, some of the internal elements of the calculation unit and the related information calculation unit may be provided inside the seismoscope.

FIG. 1 is a block diagram showing the configuration of the seismometer system according to the first embodiment of the present invention. Fig.2 (a) is a top view of the seismic device of this embodiment. Moreover, FIG.2 (b) is a side view of a seismic device, FIG.2 (c) is sectional drawing which shows the II cross section of the seismic device shown to Fig.2 (a). FIG. 3A is a perspective view showing a relative relationship between measurement axis direction vectors. FIG. 3B is a plan view of the relative relationship between the measurement axis direction vectors as viewed from above. FIG. 4 is a block diagram illustrating a configuration of a failure detection unit included in the calculation unit. FIG. 5 is a block diagram illustrating a configuration of an addition inversion unit and a switching unit included in the calculation unit. FIG. 6 is a block diagram illustrating an internal configuration of the related information calculation unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Seismograph system, 1a-1d ... Output terminal, 2 ... Seismic device, 3 ... Operation part, 5 ... Related information calculation part, 7 ... Memory | storage part, 8 ... Sensor test part, 11-14 ... Addition inversion part, DESCRIPTION OF SYMBOLS 15 ... A / D conversion part, 21-24 ... Acceleration sensor, 21a-24a ... Measurement axis, 25 ... Support body, 30 ... Failure detection part, 31 ... Abnormality detection part, 32 ... LPF abnormality detection part, 33 ... HPF abnormality Detection unit, 34 ... band abnormality detection unit, 35 ... monitoring unit, 40 ... switching unit, 51 ... waveform recording unit, 52 ... seismic intensity calculation unit, 53 ... response value / SI value processing unit, 54a to 54i ... validity check unit , S _{1 to} S ₄ , S _{5 to} S ₈ ... acceleration signal, S _{11 to} S ₁₄ , S _{15 to} S ₁₈ , S ₁₉ , S ₅₃ ... failure signal, S _{21 to} S ₂₄ ... acceleration signal, S _{31 to} S _{34 ...} complementary signal, S _{51 ...} constant-current-pulse signal, S _{52 ...} response signal , S 9 _... earthquake-related information, S _{91 ...} seismic intensity information, S _{92 ...} response value _{information, S 93} ... SI value information.

Claims (11)

A seismometer for measuring acceleration due to an earthquake,
Four acceleration sensors that measure acceleration components in different measurement axis directions;
A support for supporting the four acceleration sensors;
The support body holds the measurement axis directions of the four acceleration sensors so that vectors of the acceleration components in the measurement axis directions of the four acceleration sensors cancel each other. A seismic instrument. A seismometer for measuring acceleration due to an earthquake,
Four acceleration sensors that measure acceleration components in different measurement axis directions;
A support for supporting the four acceleration sensors;
The seismic instrument, wherein the support supports the four acceleration sensors so that the measurement axis directions of the four acceleration sensors are substantially equiangular with each other. The seismoscope according to claim 1 or 2,
A seismometer system comprising: an arithmetic unit that detects a failure of the acceleration sensor based on a vector sum of acceleration components measured by each of the four acceleration sensors.   The seismometer system according to claim 3, wherein the calculation unit detects a failure of the acceleration sensor based on a magnitude relationship between a vector sum of the acceleration components and a predetermined threshold value.   5. The seismometer system according to claim 3, wherein the calculation unit calculates the acceleration component in the failed acceleration sensor based on the acceleration component in another normal acceleration sensor. 6.   The said calculating part detects the failure of the said acceleration sensor by monitoring the gravitational acceleration component measured by each of the said four acceleration sensors, The any one of Claims 3-5 characterized by the above-mentioned. Seismometer system.   The arithmetic unit switches a connection state / non-connection state of a wiring for the acceleration sensor to output an acceleration signal indicating the magnitude of the acceleration component based on a result of detecting a failure of the acceleration sensor. The seismometer system according to any one of claims 3 to 6. The seismoscope according to claim 1 or 2,
A seismometer system comprising: a storage unit that stores acceleration signals from the four acceleration sensors. The seismoscope according to claim 1 or 2,
An seismometer system, comprising: an output terminal for providing acceleration signals from the four acceleration sensors to a host system.   The related information calculation part which calculates earthquake related information based on the acceleration signal from the said at least 3 said acceleration sensors among the said 4 acceleration sensors is further provided, The any one of Claims 3-9 characterized by the above-mentioned. Seismometer system according to item. In a three-dimensional orthogonal coordinate system for specifying earthquake-related information, the measurement axis direction of two of the four acceleration sensors is along a plane composed of two axes of the three-dimensional orthogonal coordinate system, and The seismic device is arranged such that the measurement axis direction of one of the two acceleration sensors is along one of the two axes of the three-dimensional orthogonal coordinate system. The seismometer system according to any one of claims 3 to 10, characterized by:

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