TILT MEASURING APPARATUS, TILT MEASURING METHOD, TILT MEASURING PROGRAM, AND TILT MEASURING SYSTEM

Abstract

To provide an inclination measurement device, inclination measurement method, inclination measurement program, and inclination measurement system which can accurately derive an inclination angle by determining a gravity component included in output data of a sensor that measures the gravity.SOLUTION: An inclination measurement device for measuring an inclination angle on the basis of a measurement value of a sensor that measures the gravity comprises: determination means which determines the appropriateness of a measurement value used for derivation of the inclination angle by using an absolute value and / or an actual value of the measurement value of the sensor; and inclination measurement means which derives the inclination angle on the basis of the measurement value of the sensor in accordance with the determination result of the determination means.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a tilt measurement device, a tilt measurement method, a tilt measurement program, and a tilt measurement system, and can be applied to, for example, a tilt measurement device that measures a tilt angle based on the value of a sensed gravity component. [Background technology]

[0002] For example, in systems that detect the occurrence of natural disasters such as landslides or measure the soundness of structures, tilt measurement methods that measure the tilt angle (hereinafter also referred to as "tilt" or "tilt angle") of an object (measured object) are sometimes used, and one tilt measurement method uses the output data of an acceleration sensor.

[0003] The technology described in Patent Document 1 is to attach a three-axis acceleration sensor to an object to be measured and measure the inclination of the object based on the gravitational acceleration measured by the acceleration sensor. Patent Document 1 also describes a method for removing noise when the acceleration sensor measures the inclination angle of the object during movement.

[0004] Non-Patent Document 1 discloses a method for calculating the inclination based on the gravitational acceleration included in the measurement data of an acceleration sensor. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Application No. 2006-57222 [Non-patent literature]

[0006] [Non-Patent Document 1] Analog Devices, Inc., AN-1057 Application Note, Christoper J. Fisher, “Tilt Detection Using Accelerometers”, 2010, URL: https: / / www.analog.com / jp / app-notes / an-1057.html Summary of the Invention [Problem to be solved by the invention]

[0007] Incidentally, there is a strong demand for systems to detect the occurrence of natural disasters, measure the soundness of structures, etc., to measure the inclination of the target (object to be measured) with high accuracy, because measuring inclination with high accuracy leads to improved accuracy in predicting the occurrence of natural disasters and detecting defects in structures using the inclination data.

[0008] Patent Document 1 describes a method for measuring inclination based on measurement data from an acceleration sensor, but the method assumes that the target (object to be measured) is in motion, making it difficult to apply the method to objects that are stationary, and there is a problem in that it is difficult to determine the inclination with high accuracy.

[0009] Therefore, there is a demand for a tilt measurement device, a tilt measurement method, a tilt measurement program, and a tilt measurement system that can determine the gravity component contained in the output data of a sensor that measures gravity and accurately derive the tilt angle. [Means for solving the problem]

[0010] In order to solve such problems, a first aspect of the present invention is an inclination measurement device that measures an inclination angle based on a measurement value of a sensor that measures gravity, the device comprising: a determination means that determines the validity of a measurement value used to derive an inclination angle by using an absolute value and / or an effective value of the measurement value of the sensor; and an inclination measurement means that derives an inclination angle based on the measurement value of the sensor in accordance with a determination result of the determination means. The determination means determines that the measurement value does not include components other than gravity when the difference between the absolute value and / or effective value of the measurement value in the previous measurement and the absolute value and / or effective value of the measurement value in the current measurement is less than a threshold value, and determines that the measurement value includes components other than gravity when the difference is equal to or greater than the threshold value. It is characterized by:

[0011] The second aspect of the present invention is a method for measuring an inclination angle based on a measurement value of a sensor that measures gravity, the determination means determines the validity of the measurement value used to derive the inclination angle by using the absolute value and / or effective value of the measurement value of the sensor, and the inclination measurement means derives the inclination angle based on the measurement value of the sensor according to the determination result of the determination means. The determination means determines that the measurement value does not include components other than gravity when the difference between the absolute value and / or effective value of the measurement value in the previous measurement and the absolute value and / or effective value of the measurement value in the current measurement is less than a threshold value, and determines that the measurement value includes components other than gravity when the difference is equal to or greater than the threshold value. It is characterized by:

[0012] The third aspect of the present invention is a tilt measurement program for measuring a tilt angle based on a measurement value of a sensor that measures gravity, which causes a computer to function as a determination means for determining the validity of a measurement value used to derive a tilt angle using an absolute value and / or an effective value of the measurement value of the sensor, and a tilt measurement means for deriving a tilt angle based on the measurement value of the sensor depending on a determination result of the determination means. The determination means determines that the measurement value does not include components other than gravity when the difference between the absolute value and / or effective value of the measurement value in the previous measurement and the absolute value and / or effective value of the measurement value in the current measurement is less than a threshold value, and determines that the measurement value includes components other than gravity when the difference is equal to or greater than the threshold value. It is characterized by:

[0013] The fourth present invention is characterized in that in a tilt measurement system comprising a sensor for measuring gravity, a tilt measurement device for measuring a tilt angle based on a measurement value measured by the sensor, and a management device for managing the tilt angle measured by the tilt measurement device, the tilt measurement device corresponds to the tilt measurement device according to the first present invention. Effect of the Invention

[0014] According to the present invention, the gravity component contained in the output data of a sensor that measures gravity is determined, and the tilt angle can be derived with high accuracy. [Brief description of the drawings]

[0015] [Figure 1] 1 is an overall configuration diagram showing an overall configuration of a tilt measurement system according to an embodiment; [Diagram 2] 10 is a flowchart showing an example of a processing operation of tilt measurement according to the embodiment. [Diagram 3] 5 is a flowchart showing an example of acceleration determination processing in an acceleration determination processing unit according to the embodiment (part 1). [Figure 4]13 is a flowchart illustrating an example of the acceleration determination process in the acceleration determination processing unit according to the embodiment (part 2). [Diagram 5] 11 is a flowchart illustrating an example of the acceleration determination process in the acceleration determination processing unit according to the embodiment (part 3). [Figure 6] 11 is a flowchart illustrating an example of acceleration determination processing in the acceleration determination processing unit according to the embodiment (part 4). [Figure 7] 13 is a flowchart illustrating an example of the acceleration determination process in the acceleration determination processing unit according to the embodiment (part 5). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] (A) Main embodiment DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a tilt measurement device, a tilt measurement method, a tilt measurement program, and a tilt measurement system according to the present invention will be described in detail with reference to the drawings.

[0017] (A-1) Configuration of the embodiment FIG. 1 is a diagram showing the overall configuration of a tilt measurement system according to an embodiment.

[0018] In FIG. 1, a tilt measurement system 10 according to the embodiment includes a plurality of sensor terminals 1 and a management device 2. The management device 2 is a management device that manages a tilt sensor terminal.

[0019] Although the inclination measurement system 10 in FIG. 1 illustrates a case in which the system has a plurality of sensor terminals 1, the number of sensor terminals 1 is not limited, and the system may have a single sensor terminal 1.

[0020] Also, the case where each sensor terminal 1 and management device 2 transmit and receive information wirelessly is illustrated, but this is just one example of the information transmission and reception method, and information may be transmitted and received wired. In this embodiment, the case where each sensor terminal 1 and management device 2 transmit and receive information via multi-hop wireless communication is assumed. However, information may be transmitted and received via a general-purpose wireless LAN network, a mobile phone network, or the like, without being limited to multi-hop wireless communication.

[0021] [Sensor terminal 1] The sensor terminal 1 has a wireless communication unit 11, an inclination measuring means 12, and an acceleration sensor 13. The sensor terminal 1 having the acceleration sensor 13 is provided on an object to be measured so as to be able to measure the inclination of the object to be measured.

[0022] In this embodiment, for example, the sensor terminal 1 measures the inclination of a stationary object to be measured. Note that the object to be measured may be movable (mobile), but in this embodiment, a case will be described in which the sensor terminal 1 measures the inclination of a stationary object to be measured.

[0023] The sensor terminal 1 receives commands from the management device 2, such as an instruction to start measurement by the acceleration sensor 13 and specifications regarding measurement parameters, and causes the acceleration sensor 13 to perform measurements according to the received commands. Furthermore, the sensor terminal 1 measures the inclination based on the measurement data measured by the acceleration sensor 13, and transmits the result to the management device 2.

[0024] Note that the sensor terminal 1 is not limited to transmitting only the tilt data (measured tilt value) to the management device 2, and may transmit, for example, information such as data measured by the acceleration sensor 13 and threshold values ​​used to calculate and determine the tilt data to the management device 2. This allows the management device 2 to determine the state of the object to be measured based on the acceleration data, and also allows the operator to change the operating conditions of the acceleration sensor 13 and parameters related to the calculation and determination of the tilt data.

[0025] [Acceleration sensor 13] The acceleration sensor 13 can measure the gravitational component (gravitational acceleration) in a stationary state. The acceleration sensor 13 can be a sensor that measures acceleration along one axis, or a sensor that measures acceleration along multiple axes such as two or three axes, but this embodiment illustrates the case where a sensor that measures acceleration along multiple axes is used.

[0026] In response to a measurement start request from the tilt measurement means 12, the acceleration sensor 13 measures acceleration values ​​at a designated sampling rate, measurement range, etc. The acceleration sensor 13 provides the measured measurement data to the tilt measurement means 12.

[0027] Generally, acceleration sensors 13 are of two types: digital (which read out measured values ​​as digital values ​​through a communication interface) and analog (which output analog signals according to acceleration and convert them into acceleration through AD (analog-to-digital) conversion), but the type does not matter for acceleration sensor 13 in this embodiment. Some sensor types cannot measure gravity components (for example, piezoelectric acceleration sensors), but acceleration sensor 13 in this embodiment is capable of measuring gravity components in a stationary state.

[0028] [Inclination measurement means 12] The tilt measuring means 12 acquires measurement data from the acceleration sensor 13, and measures the tilt based on the measurement data. The tilt measuring means 12 also provides the measured tilt data to the wireless communication unit 11.

[0029] The hardware of the tilt measurement means 12 can be, for example, a device having a CPU, ROM, RAM, EEPROM, etc., and various functions related to tilt measurement can be realized by the CPU executing a processing program (for example, a tilt measurement program) stored in the ROM.

[0030] As shown in FIG. 1, the tilt measurement means 12 includes a parameter setting unit 121, a tilt measurement execution unit 122, and a tilt data notification unit 123.

[0031] The parameter setting unit 121 acquires information including parameters that are the conditions for operating the acceleration sensor 13 and parameters used to calculate and determine the inclination from the management device 2 located remotely via the wireless communication unit 11, and sets these various parameters.

[0032] When the tilt measurement time arrives, the parameter setting unit 121 turns on the power supply of the acceleration sensor 13 and starts measurement by the acceleration sensor 13. At this time, the parameter setting unit 121 performs operation settings such as the measurement time, sensing range, sampling rate, and various judgment thresholds of the acceleration sensor 13. The parameter setting unit 121 performs operation settings of the acceleration sensor 13 based on parameters acquired from the management device 2.

[0033] The tilt measurement execution unit 122 measures the tilt based on the output data (hereinafter referred to as acceleration) output from the acceleration sensor 13. The tilt measurement execution unit 122 also has an acceleration determination unit 124 that determines the value of acceleration for calculating the tilt.

[0034] The acceleration determination unit 124 determines whether or not an error is included in the acceleration output from the acceleration sensor 13, and, depending on the result of the determination, causes the acceleration to be measured again.

[0035] If the acceleration value includes acceleration other than gravity, an error may occur in the measured value of the inclination. Therefore, the acceleration determination unit 124 uses either or both of the absolute value of the acceleration and the effective value of the acceleration to determine whether the measured acceleration includes acceleration other than gravity, and measures the acceleration again depending on the result. When measuring the acceleration or calculating the inclination again, the operating conditions of the acceleration sensor 13 and parameters related to the calculation of the inclination may be changed from those used previously.

[0036] The tilt measurement method of the tilt measurement execution unit 122 and the remeasurement determination method of the acceleration determination unit 124 will be described in detail in the section on operation.

[0037] The tilt data notification unit 123 provides information including the measurement value (tilt data) of the tilt measured by the tilt measurement execution unit 122 to the wireless communication unit 11, and notifies the management device 2 of the measurement.

[0038] [Wireless Communication Section 11] The wireless communication unit 11 is a wireless communication means for transmitting and receiving information to and from the management device 2. The wireless communication unit 11 provides information received from the management device 2, including parameters that are conditions for operating the acceleration sensor 13 and parameters used to calculate and determine the inclination, to the inclination measurement means 12. The wireless communication unit 11 also transmits the inclination data (measured value of the inclination) acquired from the inclination measurement means 12 to the management device 2.

[0039] [Management device 2] The management device 2 includes a wireless communication unit 21 , a control unit 22 , a display unit 23 such as a display, an input unit 24 such as a keyboard, and a storage unit 25 .

[0040] The management device 2 manages information including the operating parameters of the acceleration sensor 13 and parameters for calculating and determining the inclination for each sensor terminal 1, and stores and manages information including the inclination data acquired from each sensor terminal 1 in a memory unit 25.

[0041] The management device 2 allows an operator to set or change the operating parameters of the acceleration sensor 13. The management device 2 can also display the tilt data of each acceleration sensor 13 stored in the memory unit 25 on the display unit 23 for each acceleration sensor 13. At this time, an abnormal value range may be set to identify an abnormality in the tilt data, and when the tilt data exceeds the abnormal value range, the data may be highlighted in red or the like to be visualized.

[0042] (A-2) Operation of the embodiment Next, the operation of the tilt measurement method in the tilt measurement system 10 according to the embodiment will be described with reference to the drawings.

[0043] FIG. 2 is a flowchart showing an example of a processing operation of tilt measurement according to the embodiment.

[0044] The management device 2, through the operation of an operator, sets parameters such as the measurement time for operating the acceleration sensor 13, the sensing range, the sampling rate, and thresholds for various judgments. In addition, the management device 2, through the operation of an operator, sets parameters such as the calculation of the inclination measured based on the acceleration, and thresholds for various judgments.

[0045] Parameters may be determined for each acceleration sensor 13 and / or each sensor terminal 1, or parameters may be determined for each group of multiple acceleration sensors 13 and / or multiple sensor terminals 1 according to the measurement purpose, attribute, type, etc.

[0046] Then, the management device 2 transmits to each sensor terminal 1 information including at least parameters of the operating conditions of the acceleration sensor 13 and parameters related to the calculation of the inclination and various determinations.

[0047] In each sensor terminal 1, the parameter setting unit 121 sets the parameters of the operating conditions of the acceleration sensor 13 received from the management device 2 via the wireless communication unit 11, as well as parameters related to inclination calculation and various determinations.

[0048] First, in the sensor terminal 1, the tilt measurement means 12 waits until the set measurement time arrives (S101 / NO), and starts tilt measurement when the measurement time arrives (S101 / YES).

[0049] At this time, the parameter setting unit 121 turns on the power supply of the acceleration sensor 13, sets parameters (measurement time, sensing range, sampling rate, various judgment thresholds, etc.) of the operating conditions of the acceleration sensor 13, and starts the measurement operation of the acceleration sensor 13 (S102). The operating conditions of the acceleration sensor 13 are set by parameters, commands, etc. acquired in advance from the management device 2.

[0050] The acceleration sensor 13 starts a measurement operation according to an instruction from the tilt measurement means 12, and outputs acceleration data to the tilt measurement means 12. Furthermore, the tilt measurement execution unit 122 of the tilt measurement means 12 derives the tilt based on the output data output from the acceleration sensor 13.

[0051] Here, in order to reduce the influence of noise (e.g., high-frequency noise) contained in the acceleration, the tilt measurement execution unit 122 acquires the acceleration for a certain period of time (S103) and derives the average value of the acceleration measured within the certain period of time (S104).

[0052] For example, assume that the acceleration sensor 13 measures the three-axis acceleration at a sampling rate of 100 Hz. At this time, the tilt measurement execution unit 122 causes the acceleration sensor 13 to measure acceleration for one second until 100 samples of acceleration data are accumulated, and averages the values ​​of the 100 samples of acceleration data.

[0053] In addition, in order to maintain the measurement accuracy, it is recommended to discard the acceleration for a predetermined time after the start of measurement depending on the type of acceleration sensor 13. In that case, the tilt measurement execution unit 122 may use valid acceleration data except for the acceleration data for the predetermined time after the start of measurement.

[0054] Next, the acceleration determination unit 124 of the tilt measurement execution unit 122 performs an acceleration determination process to determine whether the output data of the acceleration sensor 13 includes any acceleration other than gravity, using either or both of the magnitude of the acceleration (absolute value of the acceleration) and the effective value of the acceleration (RMS: Root Mean Square) (S105).

[0055] If the acceleration determination unit 124 determines that no acceleration other than gravity is included (determination result OK) (S105 / NO), the tilt measurement execution unit 122 measures the tilt based on the average acceleration (S106). Furthermore, the tilt data notification unit 123 notifies the management device 2 of the tilt data via the wireless communication unit 11.

[0056] On the other hand, if the acceleration determination unit 124 determines that acceleration other than gravity is included (determination result NG) (S105 / YES), the tilt measurement execution unit 122 returns to S102 and causes the acceleration sensor 13 to measure the acceleration again.

[0057] Furthermore, when re-measuring the acceleration, it is possible to change parameters indicating the operating conditions of the acceleration sensor 13. For example, it is possible to change the sampling rate or to increase the fixed time (number of samples) for acquiring the acceleration data.

[0058] In order to avoid infinitely continuing remeasurement of acceleration, for example, the number of measurements (or the number of remeasurements) is determined and the number of measurements (or the number of remeasurements) is not exceeded. If the number of measurements is reached but it is determined that acceleration other than gravity is included (determination result NG), the tilt measurement means 12 sets the status to abnormal and notifies the management device 2 of that information.

[0059] [Acceleration determination process] 3 to 7 are flowcharts showing an example of the acceleration determination process in the acceleration determination unit 124 according to the embodiment.

[0060] The processes shown in FIGS. 3 to 7 are merely examples, and the acceleration determination unit 124 may perform any one of the processes shown in FIGS. 3 to 7, or may perform a combination of the processes.

[0061] As described above, the tilt measurement execution unit 122 measures the tilt using the derived average value of the acceleration.

[0062] Here, the method of deriving the tilt using the acceleration can be widely applied to existing technologies, and for example, the method described in Non-Patent Document 1 can be used.

[0063] The method described in Non-Patent Document 1 measures the inclination from the gravity component read by the acceleration sensor. Therefore, if acceleration other than gravity is added to the output data (acceleration data) of the acceleration sensor 13, an error will be included in the measured value of the inclination. Therefore, in order to measure the inclination with high accuracy, it is desirable to measure the inclination using the acceleration value in a completely stationary state.

[0064] [Acceleration determination process (part 1)] The method described in Non-Patent Document 1 averages the acceleration of a certain number of samples, and uses the average acceleration value to determine the inclination. However, even if the vehicle is not actually stationary, the average acceleration value for a certain period of time may coincidentally become the ideal gravitational acceleration (1G). Therefore, the process illustrated in FIG. 3 derives the magnitude of acceleration for each sample and determines whether acceleration other than gravity is included.

[0065] As illustrated in FIG. 3, the acceleration determining unit 124 derives the magnitude of the acceleration (the absolute value of the acceleration) for each sample (S201).

[0066] When the magnitude of the acceleration (absolute value of the acceleration) does not differ by a certain amount from 1 G, which is the ideal gravitational acceleration, it can be determined that the output data (acceleration) of the acceleration sensor 13 does not include acceleration other than gravity.

[0067] Therefore, the acceleration determination unit 124 calculates the difference between the absolute value of the acceleration and 1G, and compares the difference with a threshold value (S202). If the difference is not greater than or equal to the threshold value (S202 / NO), it determines that no acceleration other than gravity is included (determination result OK) (S203).

[0068] On the other hand, if the difference between the absolute value of the acceleration and 1G is equal to or greater than the threshold (S202 / YES), the acceleration determination unit 124 determines that an acceleration other than that of gravity is included (determination result NG) (S204). In this case, it can be determined that an acceleration value greater than the ideal gravitational acceleration (1G) is measured. For example, if the object to be measured is a structure such as a bridge, it can be assumed that some vibration is applied to the structure, and the acceleration sensor 13 was unable to measure the acceleration when the structure was completely stationary. Therefore, when it is determined that an acceleration other than that of gravity is included (determination result NG), the tilt measurement execution unit 122 discards the acceleration data accumulated up to that point and issues a measurement instruction to the acceleration sensor 13 again to measure the acceleration data again.

[0069] [Acceleration determination process (part 2)] Next, a description will be given of the process illustrated in Fig. 4. Here, the tilt measurement execution unit 122 not only determines the magnitude of the acceleration based on an absolute value, but also measures the effective value (Root Mean Square: RMS) of the acceleration.

[0070] As illustrated in FIG. 4, when the acceleration determination unit 124 accumulates a predetermined number (e.g., 100 samples) of valid acceleration data from the acceleration sensor 13, it temporarily stops the operation of the acceleration sensor 13 and derives the effective value (RMS value) of the acceleration (S301).

[0071] Then, the acceleration determination unit 124 compares the effective value of the acceleration with a preset threshold value (S302), and if the effective value of the acceleration is not greater than or equal to the threshold value (S302 / NO), it determines that no acceleration other than gravity is included (determination result OK) (S303).

[0072] On the other hand, if the effective value of the acceleration is equal to or greater than the threshold value (S302 / YES), the acceleration determination unit 124 determines that an acceleration other than gravity is included (determination result NG) (S304).

[0073] The acceleration determination unit 124 may combine the process illustrated in FIG. 3 with the process illustrated in FIG.

[0074] That is, a process of determining whether or not the difference between the absolute value of the acceleration and 1G is equal to or greater than a threshold value is performed, and further a process of determining whether or not the effective value of the acceleration is equal to or greater than a threshold value is performed.

[0075] If the difference between the absolute value of the acceleration and 1G is equal to or greater than a threshold value, or if the effective value of the acceleration is equal to or greater than a threshold value, it is determined that acceleration other than gravity is included (determination result NG), and the acceleration is measured again.

[0076] Furthermore, if the difference between the absolute value of the acceleration and 1G is not equal to or greater than the threshold value, and the effective value of the acceleration is not equal to or greater than the threshold value, it is determined that no acceleration other than gravity is included (determination result is OK).

[0077] [Acceleration determination process (part 3) ~ Acceleration determination process (part 5)] The tilt measuring means 12 accumulates the data of past measurements made by the acceleration sensor 13, and determines whether or not to measure again based on the amount of change in the absolute value of acceleration and / or the amount of change in the effective value of acceleration.

[0078] This is because, when tilt measurements are performed multiple times, it is assumed that the acceleration value used in the previous tilt measurements is a valid value (a value that does not include acceleration other than gravity), and if the difference between the current acceleration value and the previous acceleration value (i.e., the amount of change in acceleration) is within a certain range, the current acceleration value is also considered to be a valid value.

[0079] The method illustrated in FIG. 5 is a method in which the acceleration determination unit 124 uses the absolute value of the acceleration.

[0080] The acceleration determination unit 124 derives an absolute value of the acceleration (S401), obtains a difference between the absolute value at the previous measurement and the absolute value at the current measurement, and compares the difference with a threshold value (S402).

[0081] If the difference between the absolute value of the previous measurement and the absolute value of the current measurement is not equal to or greater than the threshold value (S402 / NO), it is determined that no acceleration other than gravity is included (determination result is OK) (S403).

[0082] On the other hand, if the difference between the absolute value at the previous measurement and the absolute value at the current measurement is equal to or greater than the threshold value (S402 / YES), it is determined that acceleration other than gravity is included (determination result NG) (S404).

[0083] The method illustrated in FIG. 6 is a method in which the acceleration determination unit 124 uses an effective value of the acceleration.

[0084] The acceleration determination unit 124 derives an effective value (RMS value) of the acceleration (S501), obtains a difference between the effective value measured previously and the effective value measured currently, and compares the difference with a threshold value (S502).

[0085] If the difference between the effective value at the previous measurement and the effective value at the current measurement is not equal to or greater than the threshold value (S502 / NO), it is determined that no acceleration other than gravity is included (determination result is OK) (S503).

[0086] On the other hand, if the difference between the effective value at the previous measurement and the effective value at the current measurement is equal to or greater than the threshold value (S502 / YES), it is determined that acceleration other than gravity is included (determination result NG) (S504).

[0087] The method illustrated in FIG. 7 is a method in which the acceleration determination unit 124 uses the absolute value and effective value of the acceleration.

[0088] The acceleration determination unit 124 derives the absolute value and effective value (RMS value) of the acceleration (S601), obtains the difference between the absolute value at the previous measurement and the absolute value at the current measurement, and compares the difference with a threshold value (S602).

[0089] If the difference between the absolute value at the previous measurement and the absolute value at the current measurement is not equal to or greater than the threshold value (S602 / NO), the process proceeds to S603.

[0090] On the other hand, if the difference between the absolute value at the previous measurement and the absolute value at the current measurement is equal to or greater than the threshold value (S602 / YES), it is determined that acceleration other than gravity is included (determination result NG) (S605).

[0091] In S603, the acceleration determination unit 124 calculates the difference between the effective value at the previous measurement and the effective value at the current measurement, and compares the difference with a threshold value (S603).

[0092] If the difference between the effective value at the previous measurement and the effective value at the current measurement is not equal to or greater than the threshold value (S603 / NO), it is determined that no acceleration other than gravity is included (determination result is OK) (S604).

[0093] On the other hand, if the difference between the effective value at the previous measurement and the effective value at the current measurement is equal to or greater than the threshold value (S603 / YES), it is determined that acceleration other than gravity is included (determination result NG) (S605).

[0094] Depending on the conditions under which acceleration sensor 13 is installed on the object to be measured, it may be difficult for acceleration sensor 13 to measure acceleration when the sensor is completely stationary. In other words, there are cases where it is difficult to obtain an accurate gravitational acceleration. In contrast, by using the methods shown in Figs. 5 to 7, it is possible to determine that an acceleration value that can be used for tilt measurement can be used even if it is not an accurate gravitational acceleration, as long as it is within a certain range of acceleration values ​​used in past tilt measurements. In other words, it is possible to flexibly use acceleration values ​​that match the installation conditions of acceleration sensor 13.

[0095] (A-3) Effects of the embodiment As described above, according to this embodiment, when measuring the inclination based on the acceleration, the accuracy of the inclination measurement is improved by obtaining the value of the acceleration in a stationary or completely stationary state. As a result, it is possible to avoid a problem in which, for example, an unexpected vibration is applied to the object to be measured (i.e., the center terminal) and the object is measured as if it is tilted even though it is not actually tilted.

[0096] (B) Other embodiments Although various modified embodiments have been mentioned in the above-described embodiment, the present invention can also be applied to the following modified embodiments.

[0097] (B-1) When the tilt data is equal to or greater than a preset threshold, the tilt measurement means 12 may notify the management device 2 of information including a message indicating an abnormality. At this time, the tilt data indicating the abnormality is also included in the information. When an abnormal value is detected, instead of notifying the above message immediately, the acceleration may be measured again and the tilt calculation may be retried.

[0098] (B-2) As described above, the methods illustrated in Figs. 3 to 7 may be performed individually or in combination. For example, when the acceleration sensor 13 is installed, the methods illustrated in Figs. 3 and 4 may be applied to ensure that acceleration other than gravity is not included, and then, if the state of the tilt data of the tilt measurement means 12 is checked and the data is reliable, the methods illustrated in Figs. 5 to 7 may be applied. In that case, for example, the management device 2 may issue a command to the tilt measurement means 12 of the sensor terminal 1 to change the operation mode of the acceleration determination process. Also, for example, the tilt measurement means 12 itself may change the operation mode of the acceleration determination process by detecting that there is no abnormality in the tilt data in the second or subsequent measurements.

[0099] (B-3) In the above embodiment, an acceleration sensor is used as an example, but other types of sensors can also be used as long as they are capable of measuring gravity. [Explanation of symbols]

[0100] 10...tilt measurement system, 1...sensor terminal, 11...wireless communication unit, 12...tilt measurement means, 13...acceleration sensor, 121...parameter setting unit, 122...tilt measurement execution unit, 123...tilt data notification unit, 124...acceleration determination unit, 2...management device, 21...wireless communication unit, 22...control unit, 23...display unit, 24...input unit, 25...memory unit.

Claims

1. In a tilt measuring device for measuring a tilt angle based on a measurement value of a sensor that measures gravity, a determination means for determining the validity of the measurement value used for deriving the tilt angle by using an absolute value and / or an effective value of the measurement value of the sensor; a tilt measuring means for deriving a tilt angle based on the measurement value of the sensor in response to a determination result of the determining means; Equipped with The determination means determines that the measurement value does not include components other than gravity when a difference between the absolute value and / or effective value of the measurement value in the previous measurement and the absolute value and / or effective value of the measurement value in the current measurement is less than a threshold value, and determines that the measurement value includes components other than gravity when the difference is equal to or greater than the threshold value. A tilt measuring device characterized by:

2. 2. The tilt measuring device according to claim 1, wherein the determining means determines whether or not the measured value includes any component other than gravity.

3. The determination means determines that the measurement value does not include components other than gravity when the difference between the absolute value of the measurement value and the gravitational acceleration is less than a threshold value, and determines that the measurement value includes components other than gravity when the difference is equal to or greater than the threshold value.

3. The tilt measuring device according to claim 1 or 2.

4. The determination means determines that the measurement value does not include components other than gravity when the effective value of the measurement value is less than a threshold value, and determines that the measurement value includes components other than gravity when the effective value is equal to or greater than the threshold value.

4. The tilt measuring device according to claim 1, wherein the tilt measuring device is a tilt measuring device.

5. 1. A tilt measurement method for measuring a tilt angle based on a measurement value of a sensor that measures gravity, comprising: a determination unit that determines the validity of the measurement value used to derive the tilt angle by using an absolute value and / or an effective value of the measurement value of the sensor; a tilt measuring means for deriving a tilt angle based on the measurement value of the sensor in response to a determination result of the determining means; The determination means determines that the measurement value does not include components other than gravity when a difference between the absolute value and / or effective value of the measurement value in the previous measurement and the absolute value and / or effective value of the measurement value in the current measurement is less than a threshold value, and determines that the measurement value includes components other than gravity when the difference is equal to or greater than the threshold value.

13. A method for measuring tilt, comprising:

6. In a tilt measurement program for measuring a tilt angle based on a measurement value of a sensor that measures gravity, Computer, a determination means for determining the validity of the measurement value used for deriving the tilt angle by using an absolute value and / or an effective value of the measurement value of the sensor; a tilt measuring means for deriving a tilt angle based on the measurement value of the sensor in response to a determination result of the determining means; and make it work. The determination means determines that the measurement value does not include components other than gravity when a difference between the absolute value and / or effective value of the measurement value in the previous measurement and the absolute value and / or effective value of the measurement value in the current measurement is less than a threshold value, and determines that the measurement value includes components other than gravity when the difference is equal to or greater than the threshold value. A tilt measurement program comprising:

7. A sensor for measuring gravity; a tilt measuring device for measuring a tilt angle based on a measurement value measured by the sensor; a management device for managing the tilt angle measured by the tilt measurement device; A tilt measurement system comprising: A tilt measuring system, characterized in that the tilt measuring device corresponds to the tilt measuring device according to any one of claims 1 to 4.

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