Earthquake sensor, earthquake detection method, and earthquake detection program

Abstract

The invention provides a seismic sensor, a seismic detection method, and a seismic detection program, which can eliminate the influence of temporary inclination generated immediately after the occurrence of vibration, and can determine the vibration with high precision. A seismic sensor (10) is provided with an acceleration acquisition unit (21), an earthquake determination unit (25), an offset adjustment unit (29), a convergence determination unit (29a), and an origin correction determination unit (29b). The offset adjustment unit (29) detects noise included in the vibration detected by the earthquake determination unit (25), and then adjusts the offset amount in accordance with the magnitude of the vibration. A convergence determination unit (29a) determines whether or not the vibration converges. An origin correction necessity determination unit (29b) determines whether or not to perform acceleration origin correction on the basis of whether or not the amount of offset calculated according to the magnitude of the vibration after the noise has been detected when a predetermined period has elapsed from the point in time when the convergence determination unit (29a) determines that the vibration has converged is the same as the previous amount of offset.

Description

Technical Field

[0001] The present invention relates to a seismic sensor for detecting earthquake motion, an earthquake detection method and an earthquake detection program. Background Art

[0002] In recent years, seismic sensors have been used that are built into gas meters, electricity meters, distribution boards, sockets, etc. and output a cut-off signal for cutting off the supply of gas, electricity, etc. when an earthquake motion of a magnitude greater than a specified value (for example, a magnitude of 5 or greater) is detected.

[0003] For example, Patent Document 1 discloses a seismic sensor comprising: an earthquake determination unit, which switches from a power saving mode to a measurement mode with higher power consumption when the measured acceleration exceeds a prescribed threshold value, and determines the occurrence of an earthquake based on the acceleration measured during a subsequent determination period; an index calculation unit, which calculates an index value representing the magnitude of the earthquake during an earthquake processing period after the determination period when the earthquake determination unit determines that an earthquake has occurred, and the seismic sensor outputs a cutoff signal when the index value during the earthquake processing period is above the threshold value, wherein the seismic sensor further comprises: a continuing earthquake determination unit, which determines the occurrence of an earthquake based on the acceleration measured during the earthquake processing period; and a cutoff determination unit, which does not output a cutoff signal unrelated to the index value when the continuing earthquake determination unit determines that no earthquake has occurred.

[0004] According to this earthquake sensitive sensor, it is possible to suppress a situation in which noise is mistakenly determined to be an earthquake and a shutdown signal is mistakenly output.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent No. 6465257

[0008] Problems to be Solved by the Invention

[0009] However, the above-mentioned conventional seismic sensor has the following problems.

[0010] That is, in the seismic sensor disclosed in the above-mentioned publication, after an earthquake is determined, it is determined that the vibration has converged, and the offset is adjusted immediately after the vibration has converged. Therefore, for example, when the detected vibration is a low-frequency vibration, and when the sensor is temporarily tilted and the tilt becomes smaller afterwards, it is difficult to maintain the determination accuracy with high accuracy due to the offset adjustment that is adjusted immediately after the vibration has converged. Summary of the invention

[0011] The present invention aims to provide a seismic sensor, an earthquake detection method, and an earthquake detection program, which can eliminate the influence of temporary tilt generated immediately after vibration occurs and perform vibration determination with high accuracy.

[0012] The seismic sensor of the first aspect of the present invention comprises: an acceleration acquisition unit, an earthquake determination unit, an offset adjustment unit, a convergence determination unit, and an origin correction need determination unit. The acceleration acquisition unit detects vibration and acquires the acceleration of the vibration. The earthquake determination unit determines whether the vibration is an earthquake based on the acceleration acquired in the acceleration acquisition unit. The offset adjustment unit adjusts the offset according to the magnitude of the vibration after detecting the noise contained in the vibration detected in the earthquake determination unit. The convergence determination unit determines whether the vibration has converged. The origin correction need determination unit determines whether to perform the acceleration origin correction based on whether the offset calculated corresponding to the magnitude of the vibration after the noise is detected after a predetermined period of time from the moment when the convergence determination unit determines that the vibration has converged is the same as the previous offset.

[0013] Here, in a seismic sensor that determines whether a vibration is an earthquake based on the acceleration of the detected vibration and adjusts an offset for eliminating the influence of noise according to the size of the vibration after the noise is detected, whether the seismic sensor is tilted is detected based on whether the offset calculated after a specified period of time (for example, 5 to 20 seconds) from the time when the vibration is determined to have converged is the same as the previous offset, and a determination is made as to whether an origin correction should be performed.

[0014] Here, the previous offset to be compared with the offset newly calculated based on the magnitude of the vibration after the noise is detected is the offset calculated when the vibration was detected last time, for example, the offset stored in the vibration sensor.

[0015] In addition, as the vibration that causes the tilt of the seismic sensor to recover after a predetermined time has passed, for example, low-frequency vibration may be considered.

[0016] Therefore, after it is determined that the vibration has converged, if the current offset is the same as the previous offset after a specified period of time (for example, after 5 to 20 seconds), it is estimated that the seismic sensor has almost no tilt. On the other hand, if the difference is large compared with the previous offset, it can be estimated that there is a high possibility that the seismic sensor will continue to tilt.

[0017] Therefore, if the vibration continues for a predetermined time or longer after convergence, the offset amount adjustment including origin correction is performed in the tilted state, and if the tilt does not continue for the predetermined time, the offset adjustment can be performed using a new offset amount after the tilt is restored.

[0018] As a result, the influence of temporary inclination occurring immediately after the vibration occurs can be eliminated, and the vibration determination can be performed with high accuracy.

[0019] A seismic sensor according to a second aspect of the present invention is the seismic sensor according to the first aspect, wherein the offset adjustment unit performs offset adjustment using a new offset amount when the offset amount is approximately the same as the previous offset amount.

[0020] Thus, when it is determined that the current offset amount is approximately the same as the previous offset amount within a predetermined period (e.g., 5 to 20 seconds) after the vibration has converged, it is estimated that the seismic sensor is almost not tilted, and offset adjustment can be performed using the newly calculated offset amount.

[0021] A seismic sensor according to a third aspect of the present invention is the seismic sensor according to the first or second aspect, wherein the offset adjustment unit performs offset adjustment including origin correction of acceleration using an offset amount larger than a previous offset amount after a predetermined period of time has elapsed.

[0022] Therefore, after the vibration has converged, if the current offset is compared with the previous offset within a specified period (for example, 5 to 20 seconds) and the difference is large, it is estimated that there is a high possibility that the seismic sensor remains tilted, so the new offset can be used for offset adjustment.

[0023] Therefore, when the seismic sensor maintains a tilted state, by performing origin correction taking the tilt into consideration, it is possible to perform appropriate correction in the tilted state.

[0024] A seismic sensor according to a fourth aspect of the present invention is the seismic sensor according to the first or second aspect, wherein the convergence determination unit determines whether the vibration has converged after a predetermined time has elapsed from the determination by the earthquake determination unit.

[0025] Thus, after determining whether the detected vibration is an earthquake and a predetermined time has passed, it is determined whether the vibration has converged, so it is easy to determine whether the seismic sensor is only temporarily tilted due to the vibration or remains tilted.

[0026] The fifth aspect of the seismic sensor of the present invention is a seismic sensor of the first or second aspect, wherein the offset adjustment unit performs origin correction of acceleration on the horizontal plane and corrects the deviation in the direction of gravitational acceleration after the origin correction determination unit determines that origin correction is required.

[0027] Thus, by performing origin correction of the acceleration on the horizontal plane that is deviated due to the inclination of the seismic sensor, it is possible to perform origin correction taking the inclination of the seismic sensor into consideration and maintain determination accuracy.

[0028] A seismic sensor according to a sixth aspect of the present invention is the seismic sensor according to the first or second aspect, wherein the offset adjustment unit adjusts the offset amount when the earthquake determination unit determines that the vibration is not an earthquake.

[0029] This makes it possible to perform appropriate offset adjustment according to the magnitude of vibration other than an earthquake.

[0030] The seventh aspect of the present invention is a seismic sensor according to the first or second aspect, further comprising a main body provided with an acceleration acquisition unit. The origin correction necessity determination unit determines whether the main body is tilted after the vibration converges based on whether the offset is the same as the previous offset.

[0031] Thus, by making a determination based on whether the newly calculated offset amount is the same as the previous offset amount, it is possible to easily determine whether the main body of the seismic sensor itself is tilted due to vibration.

[0032] A seismic sensor according to an eighth aspect of the present invention is the seismic sensor according to the first or second aspect, further comprising an acceleration waveform generating unit that generates an acceleration waveform indicating the relationship between the acceleration acquired by the acceleration acquiring unit and the elapsed time.

[0033] This makes it possible to perform earthquake determination, offset adjustment, determination of whether or not origin correction is necessary, and the like using the acceleration waveform generated based on the detected vibration acceleration.

[0034] A seismic sensor according to a ninth aspect of the present invention is the seismic sensor according to the eighth aspect, further comprising a frequency detection unit that detects the frequency of the acceleration waveform generated by the acceleration waveform generation unit.

[0035] This makes it possible to use the frequency detected from the acceleration waveform to perform earthquake determination, offset adjustment, determination of whether or not origin correction is necessary, and the like.

[0036] A seismic sensor according to a tenth aspect of the present invention is the seismic sensor according to the ninth aspect, wherein the earthquake determination unit determines whether the vibration is an earthquake based on the frequency detected by the frequency detection unit.

[0037] This makes it possible to perform earthquake determination in which a frequency detected from an acceleration waveform is used to determine whether or not a vibration is an earthquake.

[0038] The seismic sensor according to the eleventh aspect of the present invention is the seismic sensor according to the first or second aspect, further comprising an earthquake magnitude calculation unit for determining whether the earthquake is an earthquake of a predetermined magnitude or above when the earthquake determination unit determines that the earthquake is an earthquake.

[0039] Therefore, for example, when the earthquake magnitude is determined to be 5 or above, there is a risk of fire or gas leakage, and the safety of users can be improved by outputting a cutoff signal to stop the supply of energy such as electricity and gas.

[0040] A seismic sensor according to a twelfth aspect of the present invention is the seismic sensor according to the first aspect, further comprising an output unit that outputs a predetermined signal when the earthquake determination unit determines that an earthquake has occurred.

[0041] As a result, for example, when an earthquake occurs, a shutoff signal for stopping the supply of energy such as electricity and gas, a warning signal for notifying danger, and the like can be output from the output unit.

[0042] The seismic sensor of the thirteenth aspect of the present invention is the seismic sensor of the eleventh aspect, and further comprises an output unit, which outputs a prescribed signal when the earthquake determination unit determines that there is an earthquake; and further comprises an output control unit, which controls the output of the signal from the output unit according to whether the magnitude of the earthquake calculated by the earthquake magnitude calculation unit is equivalent to or above a prescribed intensity.

[0043] Therefore, when the earthquake magnitude calculation unit calculates that the magnitude of the earthquake is, for example, a magnitude 5 or above (a specified magnitude), the output unit can output a cut-off signal for stopping the supply of energy such as electricity and gas, a warning signal for warning the user, etc.

[0044] A seismic sensor according to a fourteenth aspect of the present invention is the seismic sensor according to the twelfth aspect, wherein the predetermined signal is a cutoff signal for stopping energy supply.

[0045] Thus, for example, when an earthquake with a predetermined intensity or higher is detected, the supply of energy such as electricity and gas can be stopped.

[0046] A seismic sensor according to a fifteenth aspect of the present invention is the seismic sensor according to the twelfth aspect, wherein the predetermined signal is a warning signal for giving a warning to a user.

[0047] Thus, for example, when an earthquake with a predetermined intensity or higher is detected, a warning signal can be issued to inform the user of the danger.

[0048] A seismic sensor according to a sixteenth aspect of the present invention is the seismic sensor according to the first or second aspect, further comprising a storage unit for storing the offset amount.

[0049] Therefore, it is possible to extract the previous offset amount from the storage unit provided in the vibration sensor, compare it with the newly calculated offset amount, and determine whether the origin correction is necessary.

[0050] The earthquake detection method of the seventeenth aspect of the present invention includes: an acceleration acquisition step, an earthquake determination step, an offset adjustment step, a convergence determination step, and a step for determining whether an origin correction is required. In the acceleration acquisition step, vibration is detected and the acceleration of the vibration is obtained. In the earthquake determination step, based on the acceleration of the vibration obtained in the acceleration acquisition step, it is determined whether the vibration is an earthquake. In the offset adjustment step, after detecting the noise contained in the vibration detected in the earthquake determination step, the offset is adjusted according to the size of the vibration. In the convergence determination step, it is determined whether the vibration has converged. In the step for determining whether an origin correction is required, it is determined whether to perform an origin correction of the acceleration based on whether the offset calculated corresponding to the size of the vibration after the noise is detected after a specified period of time from the moment when the vibration is determined to have converged in the convergence determination step is the same as the previous offset.

[0051] Here, in an earthquake detection method in which whether or not a vibration is an earthquake is determined based on the acceleration of the detected vibration, and an offset for eliminating the influence of noise is adjusted according to the size of the vibration after the noise is detected, whether or not the seismic sensor is tilted is detected and whether or not an origin correction is performed is determined by determining whether the offset calculated after a specified period of time (for example, 5 to 20 seconds) from the time when the vibration is determined to have converged is the same as the previous offset.

[0052] Here, the previous offset to be compared with the offset newly calculated based on the magnitude of the vibration after the noise is detected is the offset calculated when the vibration was detected last time, for example, the offset stored in the vibration sensor.

[0053] In addition, as the vibration that causes the tilt of the seismic sensor to recover after a predetermined time has passed, for example, low-frequency vibration may be considered.

[0054] Therefore, when it is determined that the current offset is the same as the previous offset after a specified period of time has passed since the vibration has converged, it is estimated that the seismic sensor has almost no tilt. On the other hand, when the difference is large compared with the previous offset, it is estimated that there is a high possibility that the seismic sensor has been tilted.

[0055] Therefore, after the vibration converges, if it continues for a predetermined time or longer, the offset amount can be adjusted including the origin correction in the tilted state, and if the tilt does not continue for the predetermined time, the offset adjustment can be performed using a new offset amount after the tilt is restored.

[0056] As a result, the influence of temporary inclination generated immediately after the vibration occurs can be eliminated, and the vibration determination can be performed with high accuracy.

[0057] The earthquake detection program of the eighteenth aspect of the present invention enables a computer to execute an earthquake detection program including an acceleration acquisition step, an earthquake determination step, an offset adjustment step, a convergence determination step, and a step for determining whether an origin correction is required. In the acceleration acquisition step, vibration is detected and the acceleration of the vibration is obtained. In the earthquake determination step, based on the acceleration of the vibration obtained in the acceleration acquisition step, it is determined whether the vibration is an earthquake. In the offset adjustment step, after detecting the noise contained in the vibration detected in the earthquake determination step, the offset is adjusted according to the size of the vibration. In the convergence determination step, it is determined whether the vibration has converged. In the step for determining whether an origin correction is required, it is determined whether to perform an origin correction of acceleration based on whether the offset calculated corresponding to the size of the vibration after the noise is detected when a specified period has passed since the moment when the vibration is determined to have converged in the convergence determination step is the same as the previous offset.

[0058] Here, in an earthquake detection procedure that determines whether a vibration is an earthquake based on the acceleration of the detected vibration and adjusts an offset for eliminating the influence of noise according to the size of the vibration, whether the seismic sensor is tilted is detected and whether an origin correction is performed is determined by determining whether the offset calculated after a specified period of time (for example, 5 to 20 seconds) from the time when the vibration is determined to have converged is the same as the previous offset.

[0059] Here, the previous offset to be compared with the offset newly calculated based on the magnitude of the vibration after the noise is detected is the offset calculated when the vibration was detected last time, for example, the offset stored in the vibration sensor.

[0060] In addition, as the vibration that causes the tilt of the seismic sensor to recover after a predetermined time has passed, for example, low-frequency vibration can be considered.

[0061] Therefore, when it is determined that the current offset is the same as the previous offset after a specified period of time has passed since the vibration has converged, it can be inferred that the seismic sensor has almost no tilt. On the other hand, when the difference is large compared with the previous offset, it can be inferred that there is a high possibility that the seismic sensor has been tilted.

[0062] Therefore, after the vibration converges, if it continues for a predetermined time or longer, the offset amount adjustment including origin correction can be performed in the tilted state, and if the tilt does not continue for the predetermined time, the offset adjustment can be performed using a new offset amount after the tilt is restored.

[0063] As a result, the influence of temporary inclination generated immediately after the vibration occurs can be eliminated, and the vibration determination can be performed with high accuracy.

[0064] Effects of the Invention

[0065] According to the seismic sensor of the present invention, the influence of temporary inclination generated immediately after the vibration occurs can be eliminated, and the vibration determination can be performed with high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 This is a control block diagram showing the structure of a seismic sensor according to one embodiment of the present invention.

[0067] Figure 2 is Figure 1 Functional block diagram generated within the seismic sensor.

[0068] Figure 3 (a) is a diagram showing an acceleration waveform when a larger offset than the previous offset is maintained for a predetermined period of time after the detected vibration is determined not to be an earthquake; Figure 3 (b) is a diagram showing an acceleration waveform in which, after the detected vibration is determined not to be an earthquake, the offset is larger than the previous offset but gradually approaches the same level as the previous offset over a predetermined period of time.

[0069] Figure 4 (a) is a diagram showing a state where the origin is deviated on the horizontal plane (X-axis, Y-axis) due to the tilt of the seismic sensor; Figure 4 (b) means from Figure 4 The state (a) is a diagram showing a state where the acceleration is offset on both the X-axis and the Y-axis by origin correction.

[0070] Figure 5 Is based on Figure 1 Flowchart of the main process of processing the earthquake detection method of the seismic sensor.

[0071] Figure 6 Yes means Figure 5 Flowchart of the detailed process of offset adjustment processing.

[0072] Description of Reference Numerals

[0073] 10: Shock sensor

[0074] 10a: Main body

[0075] 11: Acceleration sensor

[0076] 12: Controller

[0077] 13: Memory

[0078] 14: Output section

[0079] 21: Acceleration acquisition unit

[0080] 22: Acceleration waveform generation unit

[0081] 23: Vibration intensity determination / startup determination unit

[0082] 24: Frequency detection unit

[0083] 25: Earthquake Determination Department

[0084] 26: Vibration stop period determination unit

[0085] 27: Earthquake Scale Calculation Department

[0086] 28: Output control unit

[0087] 29: Offset adjustment unit

[0088] 29a: Convergence determination unit

[0089] 29b: Whether the origin correction is required

[0090] 30: Storage DETAILED DESCRIPTION

[0091] use Figure 1 to Figure 6 A seismic sensor according to an embodiment of the present invention is described below.

[0092] In addition, in the present embodiment, unnecessary detailed descriptions are sometimes omitted. For example, detailed descriptions of already known matters and repeated descriptions of substantially the same structures are sometimes omitted. This is to avoid unnecessary redundancy in the following descriptions and to facilitate understanding by those skilled in the art.

[0093] In addition, the applicant provides the drawings and the following description in order to enable those skilled in the art to fully understand the present invention, but the applicant does not intend that the subject matter described in the scope of the claims be limited by these contents.

[0094] (1) Structure of the seismic sensor 10

[0095] like Figure 1 As shown, the seismic sensor 10 of the present embodiment includes an acceleration sensor 11 , a controller 12 , and a memory 13 in a main body 10 a .

[0096] The acceleration sensor 11 is, for example, an acceleration sensor using a piezoelectric element or an acceleration sensor that detects capacitance between electrodes. The acceleration sensor 11 measures (also referred to as “samples”) acceleration and outputs it to the controller 12 .

[0097] The controller 12 is, for example, a general-purpose integrated circuit, and acquires the acceleration measured by the acceleration sensor 11 at a predetermined period, detects the occurrence of an earthquake based on the acquired acceleration, and calculates an index value indicating the magnitude of the earthquake.

[0098] In addition, the controller 12 operates in different modes such as an active mode and a sleep mode depending on the situation.

[0099] The sleep mode is a mode in which the controller 12 stops executing instructions or stops supplying clocks when receiving an interrupt and operates with limited functions. In the sleep mode, power consumption can be reduced compared to the active mode.

[0100] The active mode is a mode in which a process of determining whether the detected vibration is an earthquake or noise is performed, or an index value indicating the magnitude of an earthquake is calculated.

[0101] In addition, the CPU in the earthquake sensor 10 reads the earthquake detection program stored in the memory 13 and generates a function block (see Figure 2 ) will be described in detail later.

[0102] The memory 13 is a temporary storage unit such as a RAM (Random Access Memory) or a nonvolatile memory such as an EPROM (Erasable Programmable Read Only Memory), and stores, for example, the acceleration measured by the acceleration sensor 11 and a threshold value for earthquake determination.

[0103] Alternatively, the memory 13 may be a memory built into the acceleration sensor 11 and the controller 12 .

[0104] The output unit 14 is, for example, an output terminal of the controller 12. When the controller 12 determines that an earthquake has occurred, for example, information indicating the occurrence and magnitude of the earthquake is output to other devices via the output unit 14. In addition, when an earthquake of a predetermined magnitude or greater is detected, the output unit 14 outputs a cutoff signal, for example, for stopping the supply of energy such as electricity and gas, to an external device.

[0105] (2) Functional modules of the seismic sensor 10

[0106] like Figure 2 As shown, the seismic sensor 10 includes in the main body 10a: an acceleration acquisition unit 21, an acceleration waveform generation unit 22, a vibration intensity determination / start determination unit 23, a frequency detection unit 24, an earthquake determination unit 25, a vibration stop period determination unit 26, an earthquake magnitude calculation unit 27, an output control unit 28, an offset adjustment unit 29 and a storage unit 30.

[0107] The acceleration acquisition unit 21 acquires measurement data of acceleration measured at a predetermined period by the acceleration sensor 11. In addition, the acceleration acquisition unit 21 usually acquires measurement data of acceleration repeatedly measured at a relatively low speed (that is, a relatively large measurement period).

[0108] When the acceleration is sampled at a low speed, the controller 12 basically operates in a sleep mode (standby state or power saving mode) with low power consumption. In the standby state, since the acceleration sensor 11 is sampling at a low speed, the controller 12 can suppress power consumption by operating in the sleep mode with limited functions.

[0109] In addition, when the acceleration acquisition unit 21 acquires a vibration greater than a threshold value preset in the storage unit 30, the acceleration sensor 11 repeatedly measures the acceleration at a higher speed (i.e., a relatively small period) than when sampling at a low speed. During such high-speed sampling, the controller 12 operates in a sleep mode or an active mode.

[0110] When the earthquake determination unit 25 described later is executing processing, the controller 12 operates in the active mode (measurement mode). The transition from the power saving mode to the measurement mode is referred to as activation of the earthquake sensor 10 .

[0111] The measurement mode is an operation state in which high-speed sampling is performed, so the controller 12 may be operated in a sleep mode with limited functions or in an active mode in which the maximum computing power can be used. In the measurement mode, the sampling cycle is shortened and the controller 12 is switched from the sleep mode to the active mode, so that the power consumption becomes greater than that in the power saving mode.

[0112] The acceleration waveform generation unit 22 generates an acceleration waveform indicating the relationship between the acceleration measured by the acceleration acquisition unit 21 and the elapsed time.

[0113] The vibration intensity determination / activation determination unit 23 compares the acceleration value acquired by the acceleration acquisition unit 21 with the activation threshold stored in the storage unit 30 , and switches from the power saving mode to the measurement mode (activates the vibration sensor 10 ) when the acceleration value exceeds the activation threshold.

[0114] In addition, the vibration intensity determination / start determination unit 23 is a function on the acceleration sensor 11 side. It calculates the intensity of the vibration based on the acquisition result of the acceleration acquisition unit 21. When the vibration intensity is greater than a specified level, it switches from the power saving mode to a measurement mode with higher power consumption than the power saving mode (starting the controller 12).

[0115] Here, the vibration intensity determination process performed by the vibration intensity determination / start determination unit 23 is implemented by filtering the value of the acceleration acquired by the acceleration acquisition unit 21. At this time, the filtered acceleration is stored in the storage unit 30.

[0116] In the vibration sensor 10 of this embodiment, the vibration intensity determination / activation determination unit 23 that performs filtering processing functions as a so-called digital filter, and the existing technology can be used as filtering processing. The vibration intensity determination / activation determination unit 23 functions as a low-pass filter by calculating the moving average of the absolute value of acceleration, for example.

[0117] The frequency detection unit 24 detects the frequency of the acceleration waveform generated by the acceleration waveform generation unit 22 .

[0118] The earthquake determination unit 25 determines whether the acceleration waveform of the detected frequency is a target for earthquake determination based on the frequency detected by the frequency detection unit 24, and determines whether the vibration of the acceleration waveform is an earthquake.

[0119] Specifically, when the acceleration waveform decays to a vibration below a predetermined seismic intensity within a predetermined time (for example, maximum value - minimum value of vibration acceleration < 100 gal), the earthquake determination unit 25 excludes the acceleration waveform from the target of earthquake determination.

[0120] Furthermore, when the frequency of the detected acceleration waveform is equal to or greater than a predetermined value and the fluctuation of the period (frequency) is equal to or less than a predetermined value, the earthquake determination unit 25 excludes the acceleration waveform from the target of earthquake determination.

[0121] Furthermore, when the amplitude of the acceleration waveform detected by the peak method is equal to or larger than a predetermined value and the frequency is equal to or larger than a predetermined value, the earthquake determination unit 25 excludes the acceleration waveform from the target of earthquake determination.

[0122] In the present embodiment, after detecting that the acceleration exceeds the activation threshold value, the earthquake determination unit 25 defines one or more determination periods and performs processing in each determination period.

[0123] The vibration stop period determination unit 26 determines whether or not there is a period in which vibration has stopped in the acceleration waveform after the earthquake determination unit 25 determines that there is an earthquake.

[0124] The determination of whether there is a period in which vibration stops in the acceleration waveform may be made based on, for example, whether there is a period in which the acceleration becomes zero, or may be made based on whether the acceleration falls within a predetermined threshold range.

[0125] When the earthquake determination unit 25 determines that there is an earthquake, the earthquake magnitude calculation unit 27 determines whether the earthquake is an earthquake with a magnitude equal to or greater than a predetermined magnitude.

[0126] Furthermore, after determining that the detected vibration is an earthquake and starting calculation of an index indicating the magnitude of the earthquake, if an acceleration waveform considered to be an impact is detected, the earthquake magnitude calculation unit 27 calculates the magnitude of the earthquake excluding the acceleration waveform.

[0127] At this time, the frequency detection unit 24 detects the frequency for determining whether the detected acceleration waveform is regarded as an impact, for example, by a peak method.

[0128] The output control unit 28 controls the output of a signal from the output unit 14 that outputs a predetermined signal, depending on whether the magnitude of the earthquake calculated by the earthquake magnitude calculation unit 27 is equal to or greater than a predetermined intensity.

[0129] Here, the predetermined signal output from the output unit 14 includes, for example, a shutoff signal sent to an external device such as a power supply device or a gas supply device to stop the supply of energy such as electricity or gas.

[0130] When the earthquake determination unit 25 determines that the vibration detected by the acceleration acquisition unit 21 is noise, the offset adjustment unit 29 adjusts the offset of the acceleration waveform each time the noise is detected. In addition, when the earthquake determination unit 25 determines that the vibration obtained by the acceleration acquisition unit 21 is not an earthquake, the offset adjustment unit 29 calculates the offset according to the magnitude of the vibration after the noise is detected, and performs the offset adjustment of the acceleration waveform.

[0131] For example, the offset adjustment performed by the offset adjustment unit 29 detects, as an offset component, a noise component included in the measured acceleration, such as the amount of change in the measured value of the seismic sensor 10 caused by a change over time, the amount of change in the measured value caused by a change in the temperature, and the amount of change in the measured value caused by a change in the direction of the gravitational acceleration relative to the seismic sensor 10 when the posture of the installed seismic sensor 10 is tilted for some reason. Specifically, the offset adjustment unit 29 calculates, for example, the median value of the maximum value and the minimum value of the acceleration determined to be noise or the average value of the acceleration as the offset component.

[0132] The offset adjustment is performed to calculate an offset amount corresponding to the magnitude of vibration after noise is detected, and to eliminate the influence of the noise by using the calculated offset amount when the vibration sensor 10 is activated next time.

[0133] The calculated offset component is stored in the storage unit 30 and used for the start-up determination performed by the vibration intensity determination / start-up determination unit 23 and the earthquake determination performed by the earthquake determination unit 25. In addition, the offset amount adjusted by the offset adjuster 29 is feedback-controlled each time vibration is detected and an acceleration waveform is generated, and is updated / stored to an appropriate value according to the amount of noise.

[0134] Thus, the offset amount is always set within an appropriate range, so when detecting the frequency of the acceleration waveform, the frequency can be detected with high accuracy.

[0135] like Figure 2 As shown, the offset adjustment unit 29 includes a convergence determination unit 29 a and an origin correction necessity determination unit 29 b .

[0136] The convergence determination unit 29a determines whether the detected vibration has converged within a predetermined period (e.g., 1 second). Specifically, the convergence determination unit 29a determines whether the vibration has converged based on whether all peak-to-peak values ​​(peak-to-peak value: pp value) of the acceleration waveform within the predetermined period are less than a predetermined threshold value (e.g., less than 100 gal).

[0137] Furthermore, the convergence determination unit 29a determines whether the vibration has converged after a predetermined time has passed after the determination by the earthquake determination unit 25.

[0138] The need for origin correction determination unit 29b determines whether to perform origin correction of the acceleration waveform (acceleration) based on whether the offset calculated based on the magnitude of the vibration after noise is detected is the same as the previous offset when a specified period of time (for example, 5 to 20 seconds) has passed since the moment when the vibration is determined to have converged in the convergence determination unit 29a.

[0139] Then, the origin correction necessity determination unit 29b determines whether the seismic sensor 10 (main body 10a) is tilted after the vibration convergence, based on whether the offset is the same as the previous offset. That is, the origin correction necessity determination unit 29b compares the offset calculated after the vibration convergence with the previous offset, and when it is determined that it is greater than the previous offset, it is estimated that the tilt of the main body of the seismic sensor 10 remains unchanged, and on the other hand, when it is determined that it is equal to the previous offset, it is estimated that the tilt of the main body of the seismic sensor 10 is almost not present.

[0140] Then, when the origin correction necessity determination unit 29 b determines that the offset amount is approximately the same as the previous offset amount, the offset adjustment unit 29 performs offset adjustment using the new offset amount.

[0141] In addition, when the origin correction necessity determination unit 29b determines that the offset calculated at a time when a predetermined period of time has passed since the vibration converged (for example, 5 to 20 seconds have passed) is greater than the previous offset, the offset adjustment unit 29 uses the offset to perform offset adjustment including origin correction of the acceleration waveform.

[0142] Here, when the origin correction is determined to be necessary in the origin correction determination unit 29b, the offset adjustment unit 29 performs origin correction of the acceleration on the horizontal plane to correct the deviation in the direction of the gravitational acceleration. That is, for example, if the vertical direction is set as the Z axis, the offset adjustment unit 29 performs origin correction of the acceleration in the directions of the X axis and the Y axis (horizontal direction).

[0143] In more detail, for example, Figure 3 As shown in (a), when the earthquake determination unit 25 determines that the vibration detected in the acceleration acquisition unit 21 is not an earthquake, and the calculated offset remains larger than the previous offset for 5 to 20 seconds, an offset adjustment is performed in the offset adjustment unit 29.

[0144] Figure 3 (a) shows the acceleration waveform when the seismic sensor 10 keeps the tilted state after the vibration is detected and the tilted state is maintained until a predetermined period of time (for example, 5 to 20 seconds) has passed since the vibration converged.

[0145] In this case, the seismic sensor 10 is immediately activated after the vibration is detected, and the earthquake determination unit 25 determines that it is not an earthquake but a vibration. Within a specified period (for example, within 5 to 20 seconds) after the convergence determination unit 29a determines that the vibration has converged, the origin correction determination unit 29b calculates the offset based on the size of the vibration after detecting the noise contained in the acceleration waveform, and implements the determination on whether the origin correction is needed.

[0146] In addition, the determination that the origin correction is necessary in the origin correction necessity determination unit 29b means, for example, Figure 4 As shown in (a), on the horizontal plane (the X·Y axis plane with the vertical direction as the Z axis), the X-axis acceleration component and the Y-axis acceleration component generated by the tilt of the seismic sensor 10 are offset adjusted. Figure 4 The state shown in (b).

[0147] At this time, the origin correction necessity determination unit 29 b compares the calculated offset amount with the previous offset amount stored in the storage unit 30 , and determines whether they are substantially the same in magnitude.

[0148] Moreover, in Figure 3In the case of (a), since the offset calculated 5 to 20 seconds after the vibration converges becomes a value larger than the previous offset stored in the storage unit 30, the origin correction necessity determination unit 29b estimates that the vibration sensor 10 maintains the tilt, and thus determines that the origin correction is necessary. Therefore, in this case, the offset adjustment unit 29 performs offset adjustment including the origin correction using the offset calculated 5 to 20 seconds after the vibration converges.

[0149] Thus, even when the seismic sensor 10 is kept tilted due to vibration, it is possible to perform vibration detection with high accuracy in consideration of the tilt of the seismic sensor 10 .

[0150] Figure 3 (b) shows an acceleration waveform when, after detecting vibration such as low-frequency vibration, the seismic sensor 10 is tilted by the vibration and returns to substantially the original posture after the vibration converges.

[0151] In this case, the earthquake sensor 10 is activated immediately after the vibration is detected, and the earthquake determination unit 25 determines that it is not an earthquake but a vibration, and the convergence determination unit 29a performs a convergence determination of whether the vibration has converged. At the same time, the origin correction need determination unit 29b calculates the offset amount based on the magnitude of the vibration after the noise included in the acceleration waveform is detected, and performs the origin correction need determination.

[0152] Moreover, in Figure 3 In case (b), since the calculated offset amount after the vibration converges has dropped to be substantially the same as the previous offset amount stored in the storage unit 30, the origin correction necessity determination unit 29b infers that the tilt of the vibration sensor 10 is temporary. Therefore, in this case, the offset adjustment unit 29 performs offset adjustment using the newly calculated offset amount.

[0153] Thus, when the seismic sensor 10 is temporarily tilted due to vibration but returns to its original posture after a predetermined period of time, highly accurate vibration detection can be performed by performing offset adjustment using a new offset amount.

[0154] In addition, Figure 3 In the diagram shown in (b), once the vibration has converged, the vibration is detected again, and therefore, the offset adjustment is not performed before the vibration converges again, but is performed after the vibration converges.

[0155] The storage unit 30 stores, for example, acceleration data acquired by the acceleration acquisition unit 21 or acceleration data after filtering, determination results in the earthquake determination unit 25 , and offset component data (offset amount) used in the offset adjustment unit 29 .

[0156] (Earthquake Detection Method)

[0157] Regarding the earthquake detection method using the earthquake sensor 10 of this embodiment, Figure 5 and Figure 6 The flow chart is described as follows.

[0158] Figure 5 This is a processing flowchart showing an example of earthquake detection processing by the seismic sensor 10 according to the present embodiment.

[0159] In the seismic sensor 10 of the present embodiment, when an acceleration exceeding a specified value is detected, the mode is switched from the standby state (power saving mode) to the measurement mode to perform earthquake determination processing. When it is determined that an earthquake has occurred, the mode is switched to earthquake processing. If the magnitude of the earthquake is above a certain magnitude, a disconnect signal is output to related equipment.

[0160] Figure 5 The illustrated process is repeatedly performed in the seismic sensor 10 .

[0161] In the seismic sensor 10 , first, in step S11 , various data such as various threshold values ​​and offsets used for earthquake detection processing stored in the memory 13 or the storage unit 30 in the seismic sensor 10 are initialized.

[0162] Next, in step S12, the standby state of the earthquake sensor 10 is maintained. More specifically, the acceleration acquisition unit 21 of the earthquake sensor 10 acquires the acceleration measured by the acceleration sensor 11 in the power saving mode (acceleration acquisition step). In addition, the acceleration acquisition unit 21 performs low-speed sampling in the standby state.

[0163] Next, in step S13 , the vibration intensity determination / activation determination unit 23 of the seismic sensor 10 determines whether the seismic sensor 10 is activated (that is, whether the mode is switched from the power saving mode to the measurement mode).

[0164] In this step, if the acceleration measured in the standby state is less than a predetermined start-up threshold value (relative value based on the offset) (S13: No), the process returns to step S12 and the standby state (power saving mode) is continued. Here, the start-up threshold value is a value representing an acceleration such as 50 gal, which is initially set in step S11 and stored in the storage unit 30.

[0165] On the other hand, if the acceleration measured in the standby state is greater than the activation threshold (S13: Yes), the acceleration acquisition unit 21 switches to the earthquake determination process (measurement mode) of step S14. In the earthquake determination process (measurement mode), the acceleration acquisition unit 21 performs high-speed sampling.

[0166] Next, in step S14, the acceleration acquisition unit 21 measures the acceleration by high-speed sampling in the earthquake determination process (measurement mode), performs filtering on the measured acceleration, and saves the result value in the storage unit 30 (earthquake determination process). The filtering can be performed by the controller 12 switching to the active mode, or by the acceleration sensor 11 when the controller 12 remains in the sleep mode. In addition, the filtering process is not necessary in the earthquake determination process.

[0167] Next, in step S15, it is determined whether the detected vibration is an earthquake (earthquake determination processing). More specifically, the earthquake determination unit 25 determines whether the detected vibration is an earthquake based on whether the value of the acceleration measured in the earthquake determination processing in step S14 satisfies a predetermined condition.

[0168] For example, when the difference between the maximum value and the minimum value (peak-peak) of the acceleration measured during the determination period is equal to or larger than a predetermined threshold value (eg, 100 gal), the earthquake determination unit 25 determines that an earthquake has occurred.

[0169] Therefore, when it is determined in step S15 that an earthquake has occurred (S15: Yes), the process proceeds to earthquake processing in step S17.

[0170] Next, in the offset adjustment process of step S16, since the detected vibration is determined not to be an earthquake in the earthquake determination process of step S15, the offset adjustment unit 29 calculates the offset amount corresponding to the magnitude of the vibration and performs offset adjustment after detecting the noise contained in the acceleration waveform representing the vibration.

[0171] In this step, as an offset adjustment process, for example, the offset amount is adjusted by obtaining the average value of the acceleration from the acceleration waveform. Then, when the offset adjustment process of step S16 is completed, the process returns to the standby state of step S12.

[0172] In addition, use Figure 6 The details of the offset adjustment process in step S16 will be described in detail later in the flowchart shown.

[0173] Next, in step S17, since the detected vibration is determined to be an earthquake in the earthquake determination process in step S15, the earthquake magnitude calculation unit 27 of the seismic sensor 10 calculates an evaluation index (e.g., SI value) indicating the magnitude of the earthquake. In addition, when calculating the evaluation index, the controller 12 operates in the active mode.

[0174] Here, when the calculated evaluation index is greater than a predetermined threshold value, it is determined that an earthquake of a predetermined intensity or greater has occurred, and the evaluation index (SI value) is output to an external device (not shown) in parallel with the earthquake sensor 10. Then, a cutoff signal for cutting off the energy supply such as gas and electricity is output from the external device, and the gas and electricity are cut off.

[0175] Next, in step S18, it is determined whether the earthquake processing period has ended. The earthquake processing period is a period that is preliminarily set in step S11, and may be, for example, 120 seconds.

[0176] If it is determined in step S18 that the earthquake processing period has not ended, the process returns to step S17 and the earthquake processing is continued. On the other hand, if it is determined in step S18 that the earthquake processing period has ended, the process proceeds to step S19.

[0177] Next, in step S19, the earthquake processing is completed, the calculation of the SI value is also completed, and the SI value is reset. When the processing of step S19 is completed, the processing of this routine is temporarily terminated.

[0178] The vibration sensor 10 of this embodiment is based on Figure 6 The flowchart shown executes Figure 5 The process of the earthquake detection method shown includes the offset adjustment process of step S16.

[0179] in addition, Figure 6 The flowchart shows the Figure 5 In step S15, when it is determined that the detected vibration is not an earthquake, that is, a vibration, the process proceeds to step S16, which is the flow of the offset adjustment process.

[0180] That is, in step S20 , the acceleration acquisition unit 21 acquires data on the acceleration of the vibration, and the offset adjustment unit 29 calculates the offset amount.

[0181] Next, in step S21, when the detected vibration is not an earthquake, the offset adjustment unit 29 determines whether a predetermined time (e.g., 40 seconds) has not passed since the start of the earthquake sensor 10. Here, if the predetermined time has not passed, the process proceeds to step S22, and if the predetermined time has passed, the process switches to the standby state.

[0182] Next, in step S22, since it is determined in step S21 that the prescribed time (e.g., 40 seconds) has not passed, in order to confirm the convergence state of the vibration, the convergence determination unit 29a determines whether the pp (peak-peak) values ​​of all accelerations in the prescribed period (e.g., 1 second) are less than a prescribed threshold value (e.g., 70 to 100 gal) (convergence determination step). Here, if all the pp values ​​of the accelerations are less than the threshold value, the process proceeds to step S23, and if they are greater than the threshold value, the process returns to step S21.

[0183] Next, in step S23, since it is determined in step S22 that all the pp values ​​of the acceleration are less than the threshold value, the origin correction need determination unit 29b determines whether a predetermined period (e.g., 5 to 20 seconds) has passed since the vibration temporarily converged (origin correction need determination step). Here, if the predetermined period has passed since the convergence, the process proceeds to step S24, and if the predetermined period has not passed, the process proceeds to step S25.

[0184] Next, in step S24, since it is determined in step S23 that a predetermined period (e.g., 5 to 20 seconds) has passed since the vibration temporarily converged, the origin correction need determination unit 29b determines whether it is a predetermined time (e.g., 5 to 20 seconds) since the convergence (origin correction need determination step). Here, if it is a predetermined time (e.g., 5 to 20 seconds) since the vibration converged, the process proceeds to step S26, and if the predetermined period has passed, it is determined that the vibration is detected again during the determination and the offset adjustment cannot be performed, and the process switches to the standby state.

[0185] Next, in step S25, since it is determined in step S23 that the predetermined period has not passed since the vibration temporarily converged, the origin correction need determination unit 29b determines whether the difference between the offset amount calculated in step S20 and the previous offset amount is less than a predetermined threshold value (e.g., 10 to 30 gal) (origin correction need determination step). Here, if the difference is less than the threshold value, the process proceeds to step S26. On the other hand, if the difference is greater than the threshold value, it is determined that the current offset amount deviates from the previous offset amount, and the offset adjustment is not performed, but the process returns to step S21, and the process after step S21 is performed again.

[0186] Therefore, before a predetermined period has passed since the vibration converged, the process proceeds to step S25, where the current offset is compared with the previous offset to determine whether the difference is less than a threshold value (10 to 30 gal). If the difference is greater than the threshold value, the difference remains less than the threshold value.

[0187] Next, in step S26, since it is determined in step S24 that it is a specified time (for example, 5 to 20 seconds) since the vibration temporarily converged, or it is determined in step S25 that the difference between the current offset and the previous offset is less than the threshold, the offset is adjusted using the offset calculated at the specified time, or the offset is adjusted using a new offset (calculated in step S20) whose difference with the previous offset is less than the threshold (offset adjustment step).

[0188] Therefore, before a specified time has passed since the vibration temporarily converged, the judgment processing of steps S21 to S23 and step S25 is repeated, and when the difference between the offset amount and the previous offset amount before a specified time after the vibration converged is not less than a threshold, the offset amount calculated after the specified period can be used to implement offset adjustment.

[0189] (Main Features)

[0190] The earthquake sensor 10 of this embodiment includes an acceleration acquisition unit 21, an earthquake determination unit 25, an offset adjustment unit 29, a convergence determination unit 29a, and an origin correction need determination unit 29b. The acceleration acquisition unit 21 detects vibration and acquires the acceleration of the vibration. The earthquake determination unit 25 determines whether the vibration is an earthquake based on the acceleration acquired in the acceleration acquisition unit 21. After detecting the noise included in the vibration detected by the earthquake determination unit 25, the offset adjustment unit 29 adjusts the offset according to the magnitude of the vibration. The convergence determination unit 29a determines whether the vibration has converged. The origin correction need determination unit 29b determines whether to perform the acceleration origin correction based on whether the offset calculated according to the magnitude of the vibration after the noise is detected after a predetermined period of time from the moment when the convergence determination unit 29a determines that the vibration has converged is the same as the previous offset.

[0191] Therefore, after it is determined that the vibration has converged, if the current offset is the same as the previous offset after a specified period of time (for example, after 5 to 20 seconds), it is estimated that the seismic sensor has almost no tilt. On the other hand, if the difference is large compared with the previous offset, it is estimated that there is a high possibility that the seismic sensor is always tilted.

[0192] Therefore, if the vibration continues for a predetermined time or longer after convergence, the offset amount adjustment including origin correction is performed in the tilted state, and if the tilt does not continue for the predetermined time, the offset adjustment can be performed using a new offset amount after the tilt is restored.

[0193] As a result, the influence of temporary inclination generated immediately after the vibration occurs can be eliminated, and the vibration determination can be performed with high accuracy.

[0194] [Other embodiments]

[0195] As mentioned above, although one embodiment of the present invention has been described, the present invention is not limited to the above-mentioned embodiment, and various modifications can be made within the scope not departing from the gist of the invention.

[0196] (A)

[0197] In the above-mentioned embodiments, the earthquake sensor and the earthquake detection method are described as examples of implementing the present invention, but the present invention is not limited thereto.

[0198] For example, the present invention may be implemented as an earthquake detection program that causes a computer to execute the above-mentioned earthquake detection method using a seismic sensor.

[0199] The earthquake detection program is stored in a memory (storage unit) mounted on the seismic sensor, and the CPU reads the earthquake detection program stored in the memory to cause the hardware to execute each step. More specifically, the CPU reads the earthquake detection program, executes the acceleration acquisition step, earthquake determination step, offset adjustment step, convergence determination step, and whether origin correction is required, and can obtain the same effect as above.

[0200] Furthermore, the present invention can also be implemented as a recording medium storing an earthquake detection program of a seismic sensor.

[0201] (B)

[0202] In the above embodiment, an example is given in which, when a predetermined period (e.g., 5 to 20 seconds) has passed after the detected vibration has been determined to have converged, the offset adjustment unit 29 calculates the offset amount based on the magnitude of the vibration after the noise included in the vibration waveform is detected, and the origin correction determination unit 29b determines whether the offset amount is the same as the previous offset amount. However, the present invention is not limited to this.

[0203] For example, it is also possible to configure the device to take into account a situation where the seismic sensor is tilted due to an external impact, etc., rather than a slow vibration waveform such as a low-frequency vibration, and calculate the offset after a longer time or a shorter time has passed since the vibration converged, and compare it with the previous offset.

[0204] (C)

[0205] In the above embodiment, an example is described in which the offset adjustment unit 29 performs the offset adjustment of the acceleration waveform when the earthquake determination unit 25 determines that the detected vibration is not an earthquake. However, the present invention is not limited to this.

[0206] For example, even when it is determined that the detected vibration is an earthquake, the offset adjustment may be performed as necessary.

[0207] (D)

[0208] In the above embodiment, the output control unit 28 controls the output unit 14 to output a cutoff signal to stop the supply of energy such as electricity and gas when the earthquake vibration detected is greater than 5. However, the present invention is not limited to this.

[0209] For example, the output control unit may control the output unit so as to output a warning signal for warning the user of the occurrence of an earthquake.

[0210] (E)

[0211] In the above embodiment, an example is given in which a determination is made whether to exclude an acceleration waveform generated by detecting vibration acceleration from the target of earthquake determination based on whether the frequency is 10 Hz or more. However, the present invention is not limited to this.

[0212] For example, the prescribed value for determining whether to exclude the acceleration waveform from the target of earthquake determination is not limited to 10 Hz, and may be a value greater than 10 Hz or a value less than 10 Hz.

[0213] (F)

[0214] In the above embodiment, an example is given in which whether to exclude an acceleration waveform generated by detecting vibration acceleration from the target of earthquake determination is determined based on whether the amplitude of the acceleration waveform is 700 gal or more. However, the present invention is not limited to this.

[0215] For example, the determination condition regarding the amplitude of the acceleration waveform is not limited to the above-mentioned numerical range, and may be other conditions.

[0216] (G)

[0217] In the above embodiment, an example is given in which an earthquake is determined based on monotonic decay, periodic oscillation, amplitude, presence or absence of a vibration stop period, etc. in addition to the magnitude of the frequency of the acceleration waveform. However, the present invention is not limited thereto.

[0218] For example, as a determination means other than the magnitude of the frequency of the acceleration waveform, at least one of the above-mentioned means or a means other than the above-mentioned means may be used.

[0219] (H)

[0220] In the above-mentioned embodiment, an example in which the present invention is applied to the earthquake sensor 10 for determining an earthquake is given for explanation. However, the present invention is not limited to this.

[0221] For example, the present invention can be applied to various products in which the detection state of an acceleration sensor changes due to vibration or the like, instead of determining an earthquake.

[0222] (Industrial Applicability)

[0223] The earthquake sensor of the present invention has the effect of eliminating the influence of temporary tilt generated immediately after the vibration occurs and making a vibration determination with high accuracy. Therefore, it can be widely used in various devices for detecting the occurrence of earthquakes.

Claims

1. A seismic sensor, characterized in that: have: an acceleration acquisition unit, which detects vibration and acquires the acceleration of the vibration; an earthquake determination unit that determines whether the vibration is an earthquake based on the acceleration acquired in the acceleration acquisition unit; an offset adjustment unit that adjusts an offset amount according to a magnitude of the vibration after detecting noise included in the vibration detected in the earthquake determination unit; a convergence determination unit that determines whether the vibration has converged; The need for origin correction determination unit determines whether to perform origin correction of the acceleration based on whether the offset calculated according to the magnitude of the vibration after the noise is detected when a predetermined period has passed since the moment when the vibration is determined to have converged by the convergence determination unit is the same as the previous offset.

2. The shock sensor according to claim 1, characterized in that: The offset adjustment unit performs offset adjustment using the new offset amount when the offset amount is approximately the same as the previous offset amount.

3. The shock sensor according to claim 1 or 2, characterized in that: The offset adjustment unit performs offset adjustment including origin correction of the acceleration using the offset amount that is larger than the previous offset amount after the predetermined period has elapsed.

4. The shock sensor according to claim 1 or 2, characterized in that: The convergence determination unit determines whether the vibration has converged after a predetermined time has passed since the determination by the earthquake determination unit.

5. The shock sensor according to claim 1 or 2, characterized in that: The offset adjustment unit performs origin correction of acceleration on a horizontal plane and corrects the deviation in the direction of gravitational acceleration when the origin correction necessity determination unit determines that origin correction is necessary.

6. The shock sensor according to claim 1 or 2, characterized in that: The offset adjustment unit adjusts the offset amount when the earthquake determination unit determines that the vibration is not an earthquake.

7. The shock sensor according to claim 1 or 2, characterized in that: It also includes a main body having the acceleration acquisition unit, The origin correction necessity determination unit determines whether the main body portion is tilted after the vibration has converged, based on whether the offset amount is the same as the previous offset amount.

8. The shock sensor according to claim 1 or 2, characterized in that: The device further includes an acceleration waveform generating unit that generates an acceleration waveform indicating a relationship between the acceleration acquired by the acceleration acquiring unit and the elapsed time.

9. The shock sensor according to claim 8, characterized in that: The device further includes a frequency detection unit that detects the frequency of the acceleration waveform generated by the acceleration waveform generation unit.

10. The shock sensor according to claim 9, characterized in that: The earthquake determination unit determines whether the vibration is an earthquake based on the frequency detected by the frequency detection unit.

11. The shock sensor according to claim 1 or 2, characterized in that: The device further includes an earthquake magnitude calculation unit for determining whether the earthquake is an earthquake with a magnitude equal to or greater than a predetermined magnitude when the earthquake determination unit determines that the earthquake is an earthquake.

12. The shock sensor according to claim 1, characterized in that: An output unit is further provided for outputting a predetermined signal when the earthquake determination unit determines that an earthquake has occurred.

13. The shock sensor according to claim 11, characterized in that: Also available: an output unit that outputs a predetermined signal when the earthquake determination unit determines that there is an earthquake, An output control unit controls the output of the signal from the output unit according to whether the magnitude of the earthquake calculated by the earthquake magnitude calculation unit is equal to or greater than a predetermined intensity.

14. The shock sensor according to claim 12, characterized in that: The predetermined signal is a cutoff signal for stopping the energy supply.

15. The shock sensor according to claim 12, characterized in that: The predetermined signal is a warning signal for warning the user.

16. The shock sensor according to claim 1 or 2, characterized in that: A storage unit for storing the offset is further provided.

17. A method for detecting earthquakes, characterized in that: include: An acceleration acquisition step, detecting vibration and acquiring the acceleration of the vibration; an earthquake determination step of determining whether the vibration is an earthquake based on the acceleration of the vibration acquired in the acceleration acquisition step; an offset adjustment step of adjusting the offset amount according to the magnitude of the vibration after detecting the noise contained in the vibration detected in the earthquake determination step; A convergence determination step, determining whether the vibration has converged; The need for origin correction determination step determines whether to perform origin correction of the acceleration based on whether the offset calculated based on the magnitude of the vibration after the noise is detected after a predetermined period of time has passed since the moment when the vibration is determined to have converged in the convergence determination step is the same as the previous offset.

18. An earthquake detection program, characterized in that: The computer is caused to execute an earthquake detection method, the earthquake detection method comprising: An acceleration acquisition step, detecting vibration and acquiring the acceleration of the vibration; an earthquake determination step of determining whether the vibration is an earthquake based on the acceleration of the vibration acquired in the acceleration acquisition step; an offset adjustment step of adjusting the offset amount according to the magnitude of the vibration after detecting the noise included in the vibration detected in the earthquake determination step; A convergence determination step, determining whether the vibration has converged; The need for origin correction determination step determines whether to perform origin correction of the acceleration based on whether the offset calculated based on the magnitude of the vibration after the noise is detected after a predetermined period of time has passed since the moment when the vibration is determined to have converged in the convergence determination step is the same as the previous offset.

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