JP2010008157A - Measuring system and clinometer - Google Patents

Abstract

To provide a measurement system and an inclinometer capable of improving the reliability of a measured value as compared with the prior art.
A signal processing unit 11 uses both an output of an acceleration sensor 9 and an output of an orientation sensor 10 to specify an orientation in which an inclinometer A is inclined at an inclination angle measured by the acceleration sensor 9. The signal processing unit 11 can set in advance the azimuth of the inclinometer A that may be tilted due to the displacement of the ground as the set tilt azimuth, and if the tilt is different from the set tilt azimuth, There is a false detection avoiding means 16 for judging. When the erroneous detection avoiding means 16 determines that it is a false detection, the operation of the mode switching means 14 that switches the operation mode from the normal mode to the alert mode even if the change in the measured value of the tilt angle exceeds the first threshold value. Is invalid.
[Selection] Figure 1

Description

  The present invention relates to a measurement system and an inclinometer that are used for identifying a dangerous location where the probability of occurrence of a landslide or other landslide disaster is high by measuring an inclination angle of the inclinometer with respect to a horizontal plane.

  On slopes such as mountain slopes, earthquakes and heavy rains can trigger landslides such as landslides. In such dangerous places where the probability of occurrence of landslide disasters is high, displacement often occurs on the ground. Therefore, it has traditionally been possible to predict dangerous locations by reporting abnormalities such as cracks by reporting from residents and passers-by who live near the site, or by regular visual inspections, and take measures such as reinforcement work. Yes.

  However, since it is difficult to accurately determine the abnormality unless it is an expert, it is considered to measure the displacement of the ground with an inclinometer and identify a dangerous spot based on the measurement result.

  As an inclinometer, one having a configuration in which a sphere is accommodated in a case and the sphere rolls to turn on a switch when the case is tilted with respect to the vertical direction (see, for example, Patent Document 1). . This inclinometer is attached to a pile standing on the ground, and when the pile is tilted due to the displacement of the ground, the switch is turned on to generate an alarm. However, the inclinometer having the above-described configuration is merely for detecting whether or not a displacement has occurred on the ground, and does not measure the degree of displacement, so it is difficult to accurately identify a dangerous place.

On the other hand, what measures the displacement of the ground using a plurality of types of sensors (acceleration sensor, GPS antenna, azimuth sensor, angular velocity sensor) is also known (see, for example, Patent Document 2). Patent Document 2 describes a measurement system (a debris flow detection system) configured to install inclinometers (measurement probes) at a plurality of locations on a mountainside and transmit the measured values of each inclinometer to an observation base station by wireless communication. ing. In this type of measurement system, it is possible to estimate the degree of displacement of the ground by measuring the change in the tilt angle of the inclinometer with an acceleration sensor and analyzing the measured value.
JP 2005-259533 A (pages 8-9) Japanese Patent No. 3026197 (page 3-4)

  By the way, in the conventional measurement system described above, the inclination angle measured by the inclinometer is used as an effective measurement value regardless of the direction in which the inclinometer is actually inclined. Therefore, even when the inclinometer tilts due to a cause other than the displacement of the ground (for example, the collision of an animal with the inclinometer), the erroneous determination that the ground has been displaced due to a change in the tilt angle of the inclinometer (false detection) May be made. And the reliability of a measured value falls by the influence of a false detection, and there exists a problem that the specific precision of a dangerous location falls.

  The present invention has been made in view of the above reasons, and an object of the present invention is to provide a measurement system and an inclinometer that can improve the reliability of measurement values as compared with the prior art.

  According to the first aspect of the present invention, a plurality of inclinometers are provided in the measurement area, each of which is attached to a measurement target and measures an inclination angle of the self with respect to a horizontal plane by an acceleration sensor. A plurality of inclinometers that are capable of wireless communication, wherein each inclinometer determines in advance an orientation sensor that specifies the orientation of the inclination measured by the acceleration sensor and the orientation of the inclination to be measured. It is possible to set, and when the inclinometer is tilted in a direction different from the set direction, it has a false detection avoiding means for determining a false detection and performing a predetermined false detection process.

  According to this configuration, in the erroneous detection avoiding means, it is possible to set in advance the direction of the inclination to be measured, and when the inclinometer is tilted in a different direction from the set direction, it is determined as a false detection. For example, even if an animal collides with the inclinometer and the inclinometer tilts in a direction other than the set direction, the change in the tilt angle at this time is determined to be a false detection. And, when it is determined that there is a false detection, a predetermined false detection process is performed. For example, by performing a false detection process in which the measurement value when it is determined that a false detection is 0, the cause other than the displacement of the ground With the state after the inclinometer is tilted as an initial state, the change in the tilt angle from the initial state can be measured again. Therefore, it is possible to improve the reliability of the measured value as compared with the conventional case.

  According to a second aspect of the present invention, in the first aspect of the invention, the tilt angle changes more than a first threshold during the operation of the tilt meter in the normal mode in which the tilt angle is measured at a predetermined first sampling period. Is measured, the operation mode is switched to a warning mode for measuring an inclination angle in a second sampling period shorter than the first sampling period, and the second threshold value is exceeded for a predetermined warning time during the operation in the warning mode. A mode switching means for switching the operation mode to the normal mode if a change in the tilt angle is not measured, and the mode switching means for switching the operation mode to the alert mode when the erroneous detection avoidance means determines that the detection is erroneous. The false detection process for invalidating the operation is performed.

  According to this configuration, since the operation mode is switched to the alert mode when the change in the tilt angle equal to or greater than the first threshold is measured during the operation in the normal mode, the cycle for measuring the tilt angle is shortened. The time resolution of tilt angle measurement can be increased. In addition, during the operation in the alert mode, the operation mode is switched to the normal mode unless a change in the tilt angle equal to or greater than the second threshold is measured over a predetermined alert time, so that the cycle for measuring the tilt angle becomes longer, Power consumption can be reduced. Moreover, since the operation mode is not switched to the alert mode by the misdetection process when the false detection avoiding means determines that it is a false detection, the operation mode is switched to the alert mode at the time of erroneous detection. Can be prevented.

  The invention of claim 3 is characterized in that, in the invention of claim 1 or 2, the inclinometer has a calibration means for resetting a measured value by receiving a calibration signal.

  According to this configuration, since the measurement value can be reset by providing a calibration signal to the calibration means after the inclinometer is installed, fine adjustment to make the inclinometer parallel to the horizontal plane is not necessary when the inclinometer is installed. This makes it easy to install the inclinometer. In addition, if calibration signals are transmitted to a plurality of inclinometers at the same time, the calibration can be performed on the plurality of inclinometers all at once.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, one of the inclinometers of the plurality of inclinometers in the measurement area functions as a master unit, and the remaining inclinometers The slave unit functions as a slave unit, the master unit collects an inclination value from the slave unit through communication with the slave unit, and the slave unit has a third threshold value for a predetermined sleep time during the operation in the normal mode. If the change in the tilt angle is not measured, the operation mode is switched to the power saving mode for reducing the frequency of communication with the parent device by storing the measurement values for a plurality of times and transmitting them to the parent device in a batch, and It is characterized by comprising power saving means for switching the operation mode to the normal mode if a change in the tilt angle equal to or greater than the fourth threshold is measured during the operation in the power saving mode.

  According to this configuration, the slave unit reduces the frequency of communication with the master unit unless a change in inclination angle equal to or greater than the third threshold is measured over a predetermined sleep time during operation in the normal mode. Since the operation mode is switched to the power saving mode, it is possible to reduce the amount of power consumed for communication.

  The invention according to claim 5 is used in the measurement system according to any one of claims 1 to 4.

  According to this configuration, since the misdetection avoiding means determines that a misdetection occurs when the inclinometer tilts in a direction different from the set direction, for example, a direction other than the direction set by an animal colliding with the inclinometer Even if it is tilted in the azimuth direction, a change in the tilt angle at this time is determined as a false detection. Then, when it is determined that there is a false detection, a predetermined false detection process is performed. For example, by performing a false detection process in which the measurement value when the erroneous detection is determined is 0, for reasons other than ground displacement. With the state after the inclinometer is tilted as an initial state, the change in the tilt angle from the initial state can be measured again.

  According to the present invention, since the erroneous detection avoidance means performs a predetermined erroneous detection process when it is determined as erroneous detection, for example, by performing an erroneous detection process that sets the measured value when the erroneous detection is determined to 0. The initial state is the state after the inclinometer is tilted due to a cause other than the ground displacement, and the change in the tilt angle from the initial state can be measured again. There is an advantage that can be.

(Embodiment 1)
As shown in FIG. 2, the measurement system of the present embodiment includes a plurality of (in this case, nine) inclinometers A0 to A8 (hereinafter referred to as inclinometers unless otherwise distinguished from each other). A) and a system that measures the inclination of the object to be measured (inclination measurement system), where the measurement values of these inclinometers A are used to identify dangerous spots with a high probability of landslides and other landslides It is used for. In the following, an area where the inclinometer A is installed and is a measurement target is referred to as a measurement area B.

  As shown in FIG. 3A, the inclinometer A is attached to the upper end of a steel pipe P as a measuring object standing on the ground E of the measurement area B in a form where the lower part is buried in the ground. As shown in FIG. 3 (b), the housing 1 has a coupling portion 2 mechanically coupled to the steel pipe P, and a substantially conical radome portion 3 formed above the coupling portion 2. is doing. The housing 1 employs a waterproof structure that prevents moisture from entering the internal space, and houses various components that constitute an electric circuit. The coupling portion 2 is cylindrical and is mechanically coupled to the steel pipe P by tightening the mounting bolt 5 through the mounting bolt hole 4 formed in a part. Here, the steel pipe P is erected so that the axial direction substantially coincides with the vertical direction, and the inclinometer A measures the inclination angle in the axial direction of the steel pipe (measurement target) P with respect to the vertical direction. However, since the measured value (inclination angle) of the inclinometer A can be reset to 0 after the inclinometer A is installed by the calibration process described later, the axial direction of the steel pipe P does not completely coincide with the vertical direction. May be.

  As shown in FIG. 1, the inclinometer A includes a main circuit 6 that measures an inclination angle, a communication circuit 7 that communicates with other inclinometers A, and a battery 8 that is a power supply source for each circuit. It is provided in the housing 1.

  The communication circuit 7 communicates with another inclinometer A by wireless communication. In this embodiment, as an example, a communication method standardized as ZigBee by the IEEE (American Institute of Electrical and Electronics Engineers) is used. adopt. Although communication using ZigBee has a relatively short communication distance (for example, 70 m) and a low communication speed (for example, 250 kbps), it is characterized by low power consumption and long-term operation even with battery 8 drive. is there. In addition, ZigBee is a communication method using a so-called mesh network that can easily expand the communication area by performing multi-hop communication between a plurality of communication bases, and therefore, it is possible to communicate beyond the communication distance. . Here, the plurality of inclinometers A are two-dimensionally arranged (for example, arranged in a matrix) so that the distance to the nearest inclinometer A is within a predetermined communication distance (for example, 70 m). Therefore, even if the inclinometers A are separated from each other by the communication distance, communication is possible by relaying another inclinometer A existing between them.

  The main circuit 6 stores an acceleration sensor 9 that measures an inclination angle of the steel pipe P with respect to the vertical direction, an orientation sensor 10 that measures an orientation, a signal processing unit 11 that processes each sensor output, and various setting values and various data. Storage section 12 and clock section 13.

  As is well known, the acceleration sensor 9 outputs the magnitude of acceleration acting on a movable part (not shown) as an electrical signal. Here, the sensing direction is determined by using the direction of movement of the movable part as a sensing axis. Measure the magnitude of gravity acceleration acting in the axial direction. Here, as the acceleration sensor 9, a sensor having sensitivity with respect to at least two axes of the X axis and the Y axis orthogonal to each other in a plane orthogonal to the axial direction of the steel pipe P is used. It becomes the sensing axis.

  That is, assuming that the sensing axis is parallel to a plane (horizontal plane) perpendicular to the vertical direction on which gravity acceleration acts, the gravity acceleration does not act in the sensing axis direction in the initial state, and the output of the acceleration sensor 9 Becomes 0. On the other hand, when the steel pipe P is tilted and the casing 1 of the inclinometer A is tilted from the initial state, the sensing axis is tilted at an inclination angle θ with respect to the horizontal plane, and the component of the gravitational acceleration in the sensing axis direction acts on the movable body. . At this time, since the component of the gravitational acceleration in the sensing axis direction can be expressed by a function of the tilt angle θ, the tilt angle θ of the sensing axis with respect to the horizontal plane can be obtained from the output of the acceleration sensor 9. Furthermore, by using two axes of the X axis and the Y axis as sensing axes, the inclination angle θ is on an XY plane including the X axis and the Y axis (that is, a plane orthogonal to the axial direction of the steel pipe P). Is obtained as a vector quantity including the parameter as a parameter. Here, it is assumed that a small acceleration sensor 9 manufactured using MEMS (Micro ElectroMechanical Systems) technology and made into one chip is used.

  The direction sensor 10 measures the direction using geomagnetism and outputs the measurement result as an electrical signal. Thereby, in the signal processing unit 11, by using both the output of the acceleration sensor 9 and the output of the direction sensor 10, the direction in which the steel pipe P is inclined at the inclination angle θ measured by the acceleration sensor 9 is specified. It becomes possible. That is, although only the acceleration sensor 9 can determine only the direction of the inclination of the steel pipe P on the XY plane, the absolute direction of the inclination of the steel pipe P is specified by using the output of the direction sensor 10 together. It becomes possible to do. Therefore, when the inclinometer A is installed, the tilted direction of the steel pipe P can be specified without aligning the sensing axes (X axis, Y axis) of the acceleration sensor 9 with a predetermined direction.

  The signal processing unit 11 has a normal mode in which the tilt angle is measured at a preset first sampling period (for example, 1 hour) and a tilt angle at a second sampling period (for example, 1 minute) shorter than the first sampling period. It has mode switching means 14 for switching between two operation modes, ie, a warning mode for performing measurement. That is, when the inclinometer A is operating in the alert mode, the time interval for measuring the tilt angle is shorter than in the normal mode, and the time resolution of the measurement value is increased. The mode switching means 14 switches the operation mode to the warning mode when the measured tilt angle changes beyond the first threshold value (for example, 5 degrees) during the operation in the normal mode. During the operation, the operation mode is switched to the normal mode unless a change in the tilt angle equal to or greater than the second threshold occurs over a preset warning time (for example, 6 hours). Here, the second threshold is set to approximately 0 degrees (for example, 0.5 degrees), and switching to the normal mode is not performed if any change in the tilt angle occurs during the warning time period.

  Here, when the operation mode of the inclinometer A is switched from the normal mode to the alert mode, the other inclinometer A in the measurement area B is caused to transmit an alert signal from the communication circuit 7 to the other inclinometer A. As for the signal processing unit 11, synchronization means 15 for forcibly switching the operation mode to the alert mode is provided. Therefore, when the operation mode of one inclinometer A is switched to the alert mode, the operation modes of all inclinometers A existing in the same measurement area B as the inclinometer A become the alert mode.

  Further, the signal processing unit 11 may incline because the displacement of the ground E may cause the steel pipe P to incline (that is, for example, if the south slope, the displacement of the ground E should occur on the south side). If the head is tilted in a different direction from the set tilt azimuth, the cause other than the displacement of the ground E (for example, to the steel pipe P) It is assumed that the steel pipe P is inclined due to an animal collision), and has a false detection avoiding means 16 for judging a false detection. Then, when the erroneous detection avoiding means 16 determines that it is erroneous detection, the mode switching means 14 for switching the operation mode to the alert mode even if the change in the measured value of the tilt angle due to the erroneous detection exceeds the first threshold. The above operation is invalidated.

  Here, the misdetection avoiding unit 16 is not limited to invalidating the operation of the mode switching unit 14 when it is determined to be misdetection, and may perform any appropriate misdetection process. That is, for example, by performing an erroneous detection process that resets the inclination angle to 0 when it is determined as an erroneous detection, the state in which the steel pipe P is inclined due to a cause other than the displacement of the ground E is set as the initial state, and the initial inclination The change in angle can be measured again. Note that the false detection avoiding means 16 can perform a false detection process for adding a false detection flag to a measurement value determined to be false detection so that it can be determined whether or not it is a false detection from the measurement value record. Good.

  In the present embodiment, as described above, the signal processing unit 11 has a function as the calibration unit 17 that performs the calibration process for resetting the measurement value of the inclinometer A to zero. That is, even if the axial direction of the steel pipe P does not completely coincide with the vertical direction when the inclinometer A is installed, the inclination angle from the initial state can be set by setting the inclination angle to 0 with this state as the initial state. Can be measured. Here, the calibration means 17 starts the calibration process by receiving a calibration signal by wireless communication in the communication circuit 7, and therefore, after the installation of a plurality of inclinometers A in the measurement area B is completed, By simultaneously transmitting calibration signals to the plurality of inclinometers A, the calibration processing of the plurality of inclinometers A can be performed all at once.

  By the way, one inclinometer A0 of the plurality of inclinometers A installed in the measurement area B operates as a master unit, and the other inclinometers A1 to A8 operate as slave units. The measurement value measured by the main circuit 6 of the slave unit is transmitted to the master unit by the communication circuit 7 described above. That is, the measurement values of a plurality of slave units existing in measurement area B are collected by the master unit. In this embodiment, since the multi-hop communication method (ZigBee) is adopted, the measurement value of the lower child device relatively far from the parent device is relayed by the upper child device closer to the parent device than itself. And transmitted to the base unit. The master unit stores its own measurement values and the collected measurement values in the storage unit 12. Reading of the measured value from the parent device is performed by transmitting the measured value from the parent device to a management terminal (not shown) (personal computer or handy terminal) by wireless communication. In the example of FIG. 1, each inclinometer A is provided with an external connection terminal 18 made of a waterproof connector, and the measured value can be read by connecting a management terminal or the like to the external connection terminal 18. Is possible.

  Here, all the inclinometers A in the measurement area B are synchronized in operation timing (measurement and communication timing) with the parent device as a reference. Specifically, the operation timing is synchronized by using time data transmitted from the management terminal to the master unit and transferred from the master unit to each slave unit before starting the measurement of the tilt angle. . The slave unit, together with the measurement value received from the slave unit (distant from the master unit) lower than its own, the slave unit or the master unit with its own measured value higher than itself (close to the master unit). Send to.

  Here, inclinometers A1 to A8 as slave units transmit measured values to the base unit (inclinometer A0) every time the tilt angle is measured in the normal mode and the alert mode. However, since power is consumed every time a measurement value is transmitted, it is desirable to reduce power consumption by reducing the opportunity to transmit the measurement value as much as possible.

  Therefore, in this embodiment, at least the inclinometers A1 to A8 used as the slave units are stored in the storage unit 12 during the measurement of the tilt angle a plurality of times, and the measurement values for the plurality of times are collectively stored in the parent unit. The signal processing unit 11 is provided with a function as power saving means 19 for switching between two operation modes of the power saving mode transmitted to the machine (inclinometer A0) and the normal mode. That is, during operation in the power saving mode, the frequency of communication with the parent device (inclinometer A0) is lower than in the normal mode, and the power consumption for communication can be reduced. During the operation in the normal mode, the power saving means 19 switches the operation mode to the power saving mode when a state in which the inclination angle does not change more than the third threshold continues for a predetermined sleep time (for example, 24 hours). If the tilt angle changes more than a fourth threshold value (for example, 0.5 degrees) during operation in the power saving mode, the operation mode is switched to the normal mode. Here, the third threshold is set to approximately 0 degrees (for example, 0.5 degrees), and switching to the power saving mode is not performed if any change in the tilt angle occurs during the sleep time period.

  In addition, various setting values such as the above-described threshold values (excluding the second and third threshold values), the first sampling period, the second sampling period, the warning time, the sleep time, and the set inclination direction are set by the management terminal. And stored in the storage unit 12 of the inclinometer A. Here, the first threshold is 5 degrees, the fourth threshold is 0.5 degrees, the first sampling period is 1 hour, the second sampling period is 1 minute, the warning time is 6 hours, and the sleep time is 24 hours. It is set as an initial value. As the set inclination azimuth, two out of 16 azimuths can be set. Furthermore, the installation position (latitude, longitude) of the inclinometer A, the current date and time, the terminal number for identifying the management terminal, the distinction between the parent device and the child device, and for identifying the individual device in the child device In the case of the slave unit number and the master unit, setting values such as nodes (maximum 20 units) are also set by the management terminal. Note that the communication cycle for transmitting the measurement value from the slave unit to the master unit may be set separately from the first sampling cycle and the second sampling cycle. In this case, the communication cycle is also set by the management terminal.

  Hereinafter, the operation of the measurement system of the present embodiment will be described with reference to the flowcharts shown in FIGS. Note that the flowcharts of FIGS. 4 to 6 show an operation example of the slave unit (inclinometer A1) closest to the master unit (inclinometer A0).

  When the power is turned on (S1), the inclinometer A1 enters a communication standby state (S2). In this state, when a setting confirmation signal is received from the management terminal (S3: Yes), the current various setting values (initial values) in the storage unit 12 are returned to the management terminal (S4). When the inclinometer A1 receives various setting values changed in the management terminal from the management terminal (S5: Yes), the inclinometer A1 updates the setting value (S6) and shifts to a measurement standby state waiting for a measurement start signal. (S7). Here, the measurement start signal is transmitted from the management terminal unit to the master unit (inclinometer A0) together with the time data, and is transferred to each slave unit together with the time data by the master unit.

  Thus, when the inclinometer A1 receives the measurement start signal from the master unit together with the time data (S8), the inclinometer A1 ends the measurement standby state and synchronizes with respect to the operation timing (S9). Further, since the multi-hop communication method (ZigBee) is adopted in this embodiment, the inclinometer A1 transfers the measurement start signal and time data to the slave units (inclinometers A2 to A8) lower than itself. (S10).

  Thereafter, the inclinometer A1 performs a calibration process for resetting the measured value (S11), starts measuring the tilt angle (S12), measures the tilt angle, and records the measured value in the storage unit 12 (S13). What is stored in the storage unit 12 at this time is measurement data including the measured tilt angle (measured value), the tilted azimuth, and the measurement date and time. Further, the inclinometer A1 receives measurement data from the slave units (inclinometers A2 to A8) lower than itself, and transfers the received measurement data to the parent unit together with its own measurement data (S14). The measurement data transferred at this time is added with a slave unit number for specifying the transmission source and an alarm indicating insufficient battery capacity. The measurement data collected by the parent device is transmitted to the management terminal device together with the measurement data of the parent device itself when the parent device receives a transmission request signal from the management terminal device.

  By the way, when the power is turned on, the inclinometer A1 operates in the normal mode. Therefore, the measurement of the inclination angle (S13) and the transmission of the measurement data (S14) are periodically repeated in the first sampling period. However, the operation mode of the inclinometer A1 may be switched from the normal mode to the warning mode or the power saving mode by the mode switching means 14 and the power saving means 19.

  That is, as shown in FIG. 5, when the change in the inclination angle becomes equal to or greater than the first threshold (S21: Yes), the operation mode is switched from the normal mode to the alert mode by the mode switching means 14 (S22). The cycle of angle measurement and measurement data transmission is switched from the first sampling cycle to the second sampling cycle. At this time, a warning signal is transmitted to the other inclinometers A0, A2 to A8 by the synchronization means 15 (S23). Thereafter, when the change of the tilt angle during the warning mode is less than the second threshold value (S25: Yes) at the end of the warning time period (S24), the mode switching means 14 changes the operation mode from the warning mode to the normal mode. It is switched (S26). Here, the other inclinometers A0, A2 to A8 that have received the warning signal also perform the operations of steps S22 to S26.

  In addition, as shown in FIG. 6, when the state in which the change in the tilt angle does not reach the third threshold continues for the sleep time (S31: Yes), the power saving means 19 switches the operation mode from the normal mode to the power saving mode ( S32). Thereafter, if there is a change equal to or greater than the fourth threshold value in the tilt angle (S33: Yes), the power saving means 19 switches the operation mode from the power saving mode to the normal mode (S34).

  As described above, in the measurement system of the present embodiment, the inclinometer A has a high time resolution of measurement values by switching to the alert mode when the tilt angle changes by more than the first threshold during operation in the normal mode. Thus, more detailed data than in the normal mode can be taken. That is, if the tilt angle changes by more than the first threshold, it indicates that the ground E at the point where the inclinometer A is installed is displaced, and the measured value at that point is considered to be highly urgent data. Therefore, it is very useful to collect more detailed data about the point. On the other hand, if the tilt angle hardly changes during the operation in the alert mode, the time interval for measuring the tilt angle becomes longer by switching to the normal mode, and the power consumption can be suppressed to be lower than that in the alert mode.

  Moreover, when any inclinometer A in the measurement area B is switched to the warning mode, all the inclinometers A in the measurement area B are switched to the warning mode by the warning signal transmitted from the inclinometer A. Detailed data can be obtained for the entire B area. As a result, the identification accuracy of the dangerous spot in the measurement area B is improved.

  Furthermore, in this embodiment, by providing the false detection avoiding means 16, even if the inclination angle changes, the inclination direction measured by the direction sensor 10 is different from the set inclination direction at this time. The tilt angle is determined to be erroneous detection, and even if the change in the measured value of the tilt angle due to the erroneous detection exceeds the first threshold, the operation mode is not switched to the alert mode. That is, even if an erroneous detection occurs due to an animal colliding with the steel pipe P, the erroneous detection avoiding means 16 may invalidate the influence of the erroneous detection by performing an appropriate erroneous detection process. it can.

  Inclinometers A1 to A8 as slave units, when the inclination angle hardly changes over the sleep time during operation in the normal mode, the frequency of communication is reduced by switching to the power saving mode. Can also reduce power consumption. That is, when there is almost no change in the tilt angle, it indicates that the ground E at the point where the inclinometer A is installed is not displaced, and the measured value at that point is considered to be data with low urgency. Even if the frequency at which the measured value at this point is transmitted to the base unit is reduced, no particular problem occurs.

  The measurement result obtained by the measurement system of the above embodiment is collected from the parent device by the management terminal device, for example, once a week. Then, by analyzing the measurement result, it is possible to estimate the state (displacement state) of the ground E in the measurement area B and determine whether or not it is a dangerous place where a landslide or other landslide disaster is likely to occur. Is possible. The inclinometer A constituting this measurement system is installed in the same measurement area B for a predetermined period (for example, one year), and if there is no change in the inclination angle during that period, it is collected and installed in another measurement area. With respect to the measurement area B that is determined to be a dangerous spot by measurement using this measurement system, it is desirable to continue monitoring with a measuring instrument (for example, a laser displacement meter) that can measure the displacement of the ground more accurately.

  Note that an alarm device using light or sound may be added to the inclinometer A so that an alarm is issued from the alarm device when the tilt angle exceeds a certain value. The battery 18 of the inclinometer A may be a secondary battery, and the secondary battery may be charged with a solar battery or the like. In this case, the frequency of maintenance of the inclinometer A can be reduced.

  By the way, in the said embodiment, although the example which uses the measuring system of this invention for the identification of the dangerous location with high probability of occurrence of landslides, such as a landslide, it is also considered using the measuring system of this invention for other uses. It is done. For example, it is possible to measure the inclination of a building such as a house or a bridge using the measurement system of the present invention. In this case, the steel pipes P as measurement objects are respectively fixed to a plurality of columns constituting the building. To do. Thereby, it becomes possible to measure the inclination angle of the column with respect to the vertical direction by the inclinometer A attached to each steel pipe P, and the inclination of the building can be measured by the measurement system.

It is a schematic block diagram which shows the structure of the inclinometer of Embodiment 1 of this invention. An inclinometer same as the above is shown, (a) is a schematic view of an installed state, and (b) is a schematic perspective view. It is a schematic perspective view which shows a measurement area same as the above. It is a flowchart which shows the basic operation | movement of a subunit | mobile_unit same as the above. It is a flowchart which shows operation | movement of a subunit | mobile_unit same as the above. It is a flowchart which shows operation | movement of a subunit | mobile_unit same as the above.

Explanation of symbols

7 Communication circuit 9 Acceleration sensor 10 Direction sensor 14 Mode switching means 16 False detection avoidance means 17 Calibration means 19 Power saving means A, A0 to A8 Inclinometer B Measurement area E Ground

Claims (5)

  Each measuring object is equipped with multiple inclinometers in the measurement area that are attached to the measuring object and measures its own inclination angle with respect to the horizontal plane using an acceleration sensor, and a communication circuit provided for each inclinometer between multiple inclinometers in the measurement area In each inclinometer, each inclinometer can set an orientation sensor that specifies the orientation of the inclination measured by the acceleration sensor and the orientation of the inclination to be measured. And a false detection avoiding means for performing a predetermined false detection process by judging that the tilt meter is tilted in a different direction from the current orientation.   When the change of the tilt angle equal to or greater than the first threshold is measured during the operation in the normal mode in which the tilt angle is measured at a predetermined first sampling cycle, the inclinometer is shorter than the first sampling cycle. Switch the operation mode to the alert mode that measures the tilt angle at the sampling period, and if the change of the tilt angle over the second threshold is not measured over the predetermined alert time during the alert mode, the operation mode is normal Mode switching means for switching to a mode, and the false detection avoiding means performs the false detection processing for invalidating the operation of the mode switching means for switching the operation mode to the warning mode when it is determined that false detection has occurred. The measurement system according to claim 1.   The measurement system according to claim 1, wherein the inclinometer includes a calibration unit that resets a measurement value by receiving a calibration signal.   Of the plurality of inclinometers in the measurement area, one inclinometer functions as a master unit and the remaining inclinometers function as slave units. The master unit communicates with the slave units from the slave unit. The slave unit collects the tilt values, and the slave unit stores the measured values for a plurality of times if the change in the tilt angle equal to or greater than the third threshold is not measured over a predetermined sleep time during the operation in the normal mode. The operation mode is switched to the power saving mode that reduces the frequency of communication with the parent device by transmitting to the parent device in a lump, and the change in the tilt angle that is greater than or equal to the fourth threshold is measured during the operation in the power saving mode. The measurement system according to any one of claims 1 to 3, further comprising power saving means for switching the operation mode to the normal mode. An inclinometer used in the measurement system according to any one of claims 1 to 4.

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