Analysis system, analysis method for analysis system, server device, control method for server device, and program

Abstract

An analysis system 1 includes a wireless sensor 10 and a server device 20 capable of communicating with each other. A wireless sensor 10 includes a first controller 11 that obtains a measurement value of a physical quantity of a measurement target measured at predetermined measurement times distributed at predetermined intervals, and transmits the obtained measurement value of the physical quantity to a server device 20. The server device 20 includes a second controller 21 that combines measured values of physical quantities measured at measurement times distributed at predetermined intervals received from the wireless sensor 10 to obtain combination information as time-continuous measured values, performs frequency analysis on the combination information, and outputs a result of the frequency analysis of the combination information.

Description

[0001] Cross Reference to Related Applications

[0002] This application claims priority to and the benefit of Japanese Patent Application No. 2023-031437 filed March 1, 2023, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present disclosure relates to an analysis system, an analysis method of an analysis system, a server apparatus, a control method of a server apparatus, and a program. BACKGROUND

[0004] Frequency analysis techniques of signals such as Fourier transform and frequency filter are known (refer to Patent Literature 1 (PTL 1) and Patent Literature 2 (PTL 2)).

[0005] In addition, a small wireless sensor powered by a battery is known. Such a wireless sensor measures various physical quantities such as temperature, pressure, vibration, and the like, and transmits a measurement value of the physical quantity to another apparatus via wireless communication.

[0006] Bibliographic List

[0007] Patent Literature

[0008] PTL 1: JP 2001-021597 A

[0009] PTL 2: JP 2019-035666 A SUMMARY

[0010] (TECHNICAL PROBLEM)

[0011] When a result of frequency analysis is performed on a measurement result of a wireless sensor and the analysis result is used for another apparatus, the frequency analysis can be performed by the wireless sensor or the other apparatus. Here, in order to perform the frequency analysis of the signal, it is necessary to perform arithmetic processing on data for a certain period of time. Therefore, when the result of the frequency analysis of the measurement value of the physical quantity is to be made available to the other apparatus, the wireless sensor must transmit a large amount of data on the measurement result before the frequency analysis or after the frequency analysis. Transmission of a large amount of data via wireless communication consumes electric power and can reduce the communication speed of the wireless sensor. In this case, the conventional configuration transmits and receives a measurement value of a physical quantity measured only for a short period of time, which depletes the battery of the wireless sensor. In other words, the other apparatus can use only a result of frequency analysis of a measurement value for a certain short period of time.

[0012] Therefore, it would be helpful to enable a result of frequency analysis of a measurement value measured by a wireless sensor for a longer period of time to be used by another apparatus.

[0013] (SOLUTION TO THE PROBLEM)

[0014] The analysis system according to at least one embodiment is:

[0015] (1) An analysis system including a wireless sensor and a server device capable of communicating with each other, wherein

[0016] The wireless sensor includes a first controller configured to:

[0017] obtain measurement values of a physical quantity of a measurement object measured at measurement times distributed at predetermined intervals; and

[0018] transmit the obtained measurement values of the physical quantity to the server device,

[0019] The server device includes a second controller configured to:

[0020] combine the measurement values of the physical quantity received from the wireless sensor, which are measured at the measurement times distributed at the predetermined intervals, to obtain combination information as time-continuous measurement values;

[0021] perform frequency analysis on the combination information; and

[0022] output a result of the frequency analysis of the combination information.

[0023] In this way, after combining the measurement values of the physical quantity of the measurement object measured at the measurement times distributed at the predetermined intervals, the frequency analysis is performed, so that the result of the frequency analysis of the measurement values over a longer period of time can be used by another device on the server device side.

[0024] According to an embodiment,

[0025] (2) In the analysis system according to (1),

[0026] The second controller of the server device is configured to perform window function processing on the measurement values of the physical quantity measured at the measurement times distributed at the predetermined intervals, and combine the measurement values on which the window function processing is performed to obtain combination information.

[0027] In this way, the window function is applied, and then the measurement values are combined to obtain the combination information, thereby contributing to the prevention of errors in the frequency components due to signal discontinuity.

[0028] According to an embodiment,

[0029] (3) In the analysis system according to (1) or (2),

[0030] The second controller of the server device is configured to transmit a time interval to the wireless sensor, and

[0031] The first controller of the wireless sensor is configured to obtain the measurement value of the physical quantity using the time interval received from the server device as the predetermined interval.

[0032] In this way, the wireless sensor obtains the measurement value of the physical quantity based on the time interval received from the server device, and the time interval of the measurement of the physical quantity can be set by the server device.

[0033] According to an embodiment,

[0034] (4) In the analysis system according to any one of (1) to (3),

[0035] The second controller of the server device is configured to transmit a prescribed time to the wireless sensor, and

[0036] The first controller of the wireless sensor is configured to obtain the measurement value of the physical quantity using the prescribed time received from the server device as the measurement time.

[0037] In this way, the wireless sensor obtains the measurement value of the physical quantity using the prescribed time received from the server device as the measurement time, and the measurement time of the measurement value of the physical quantity can be set by the server device.

[0038] According to an embodiment,

[0039] (5) In the analysis system according to (1) or (2),

[0040] The second controller of the server device is configured to transmit a range of time intervals to the wireless sensor, and

[0041] The first controller of the wireless sensor is configured to, each time the wireless sensor obtains the measurement value of the physical quantity, randomly determine a time interval within the range received from the server device, and obtain the measurement value of the physical quantity using the randomly determined time interval as the predetermined interval.

[0042] In this way, the wireless sensor randomly determines a time interval within a certain range and obtains the measurement value of the physical quantity at the randomly determined time interval, and thus, it is possible to avoid missing a signal that occurs at regular intervals.

[0043] According to an embodiment,

[0044] (6) In the analysis system according to any one of (1) to (5),

[0045] The second controller of the server device is configured to transmit the number of measurement values to be measured at the measurement time to the wireless sensor, and

[0046] The first controller of the wireless sensor is configured to obtain as many measurement values of the physical quantity at the measurement times as the number received from the server device.

[0047] In this way, the wireless sensor obtains only the number of measurement values of the physical quantity set by the server device, thereby allowing the server to set the number of samples of the measurement values of the physical quantity.

[0048] The analysis method of the analysis system according to at least one embodiment is:

[0049] (7) An analysis method for an analysis system including a wireless sensor and a server device capable of communicating with each other, the analysis method including:

[0050] the wireless sensor obtaining measurement values of a physical quantity of a measurement object measured at predetermined measurement times distributed at predetermined intervals; and transmitting the obtained measurement values of the physical quantity to the server device, and

[0051] the server device combining the measurement values of the physical quantity received from the wireless sensor measured at the measurement times distributed at the predetermined intervals to obtain combination information as time-continuous measurement values; performing frequency analysis on the combination information; and outputting a result of the frequency analysis of the combination information.

[0052] In this way, after combining the measurement values of the physical quantity of the measurement object measured at the measurement times distributed at the predetermined intervals, the frequency analysis is performed, so that the result of the frequency analysis of the measurement values over a longer period of time can be used on the server device side.

[0053] The server device according to at least one embodiment is:

[0054] (8) A server device including a controller capable of communicating with a wireless sensor configured to obtain measurement values of a physical quantity of a measurement object at predetermined measurement times distributed at predetermined intervals, the controller being configured to:

[0055] receive the measurement values from the wireless sensor;

[0056] combine the measurement values of the physical quantity received from the wireless sensor measured at the measurement times distributed at the predetermined intervals to obtain combination information as time-continuous measurement values;

[0057] perform frequency analysis on the combination information; and

[0058] output a result of the frequency analysis of the combination information.

[0059] Thus, after combining the measurement values of the physical quantity of the measurement target measured at the measurement times distributed at the predetermined intervals, frequency analysis is performed, so that the result of the frequency analysis of the measurement values over a longer period of time can be used on the server device side.

[0060] The server device control method according to at least one embodiment is:

[0061] (9) A server device control method, the server device including a controller capable of communicating with a wireless sensor configured to obtain measurement values of a physical quantity of a measurement target at predetermined measurement times distributed at predetermined intervals,

[0062] the controller receiving the measurement values from the wireless sensor; combining the measurement values of the physical quantity measured at the measurement times distributed at the predetermined intervals received from the wireless sensor to obtain combination information as time-continuous measurement values; performing frequency analysis on the combination information; and outputting a result of the frequency analysis of the combination information.

[0063] Thus, after combining the measurement values of the physical quantity of the measurement target measured at the measurement times distributed at the predetermined intervals, frequency analysis is performed, so that the result of the frequency analysis of the measurement values over a longer period of time can be used on the server device side.

[0064] The program according to at least one embodiment is:

[0065] (10) A program causing a computer capable of communicating with a wireless sensor configured to obtain measurement values of a physical quantity of a measurement target at predetermined measurement times distributed at predetermined intervals to perform the following processes:

[0066] a process of receiving the measurement values from the wireless sensor;

[0067] a process of combining the measurement values of the physical quantity measured at the measurement times distributed at the predetermined intervals received from the wireless sensor to obtain combination information as time-continuous measurement values;

[0068] a process of performing frequency analysis on the combination information; and

[0069] a process of outputting a result of the frequency analysis of the combination information.

[0070] Thus, after combining the measurement values of the physical quantity of the measurement target measured at the measurement times distributed at the predetermined intervals, frequency analysis is performed, so that the result of the frequency analysis of the measurement values over a longer period of time can be used on the server device side.

[0071] (Beneficial Effects)

[0072] Embodiments of the present disclosure enable the results of frequency analysis of measurement values ​​measured by a wireless sensor over a long period of time to be used by another device. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] In the attached figure:

[0074] Figure 1 is a schematic diagram for explaining frequency analysis performed by a configuration according to a comparative example;

[0075] Figure 2 is a schematic diagram showing an example configuration of an analysis system according to an embodiment;

[0076] Figure 3 It shows Figure 2 A schematic diagram of a detailed example configuration of some functional blocks of the analysis system;

[0077] Figure 4 Is used to illustrate the Figure 2 Schematic diagram of frequency analysis performed by the analysis system;

[0078] Figure 5 It shows Figure 2 A flowchart of an example operation of a wireless sensor;

[0079] Figure 6 It shows Figure 2 A flowchart of an example operation of a server device;

[0080] Figure 7 is a schematic diagram showing an example of a signal to be analyzed;

[0081] Figure 8 It shows Figure 7 A schematic diagram of an example of the signal shown in after frequency analysis; and

[0082] Figure 9 It shows Figure 7 Schematic diagram of an example of the signal shown in FIG after frequency analysis. DETAILED DESCRIPTION

[0083] <Comparative Example>

[0084] The analysis system according to the comparative example includes a wireless sensor that measures a physical quantity, and a server device that receives a measurement value of the physical quantity from the wireless sensor and performs a prescribed process. The wireless sensor measures the physical quantity, performs a process such as analog-digital (AD) conversion on the measurement value of the physical quantity, and transmits the converted measurement value to the server device via low-speed wireless communication. The server device performs a prescribed process on the measurement value of the physical quantity received from the wireless sensor, and outputs the processed measurement value to a display or the like. In this configuration, when a frequency analysis such as a Fourier transform is performed on the measurement result of the wireless sensor and the analysis result is used by the server device, the frequency analysis can be performed at the wireless sensor or the server device. In other words, two configurations can be considered: the wireless sensor performs the frequency analysis on the measurement value and transmits the analyzed measurement value to the server device, or the wireless sensor does not perform the frequency analysis but transmits the measurement value of the physical quantity to the server device, and the frequency analysis is performed at the server device side.

[0085] In such a configuration, the wireless sensor or the server device performs a fast Fourier transform (FFT). A typical short-time Fourier transform (STFT) is a Fourier transform that applies a moving window function to a measurement value. Here, the wireless sensor or the server device moves the window function in a manner that the application range of the window functions overlap each other, and processes in a manner that does not lose time-series data. When the FFT is performed at the wireless sensor side, in order to reduce the amount of data to be transmitted, the wireless sensor can detect only a peak frequency after processing the FFT, and transmit the data at the frequency to the server device.

[0086] A frequency analysis such as an FFT requires arithmetic processing on data for a certain period of time, and therefore, according to the comparative example, a large amount of data required for the FFT operation or after the FFT operation needs to be collected and transmitted. As a result, the low-speed communication takes a long time to transmit the data, thereby increasing the power consumption of the wireless sensor. In the configuration in which the FFT is performed at the wireless sensor side, the power consumption is further increased due to the arithmetic processing of a central processing unit (CPU), and a large amount of memory is required. When peak frequency extraction or the like is performed, a large-capacity memory and power consumption associated with the arithmetic operation are also required, and data other than the selected data is also lost. Even in the configuration using the STFT, it is common to overlap or shorten the application range of adjacent window functions, resulting in power consumption for processing and transmitting a large amount of data.

[0087] Therefore, transmitting a large amount of data through wireless communication consumes power proportional to the amount of data, and can reduce the communication speed of the wireless sensor. In this case, in the configuration according to the comparative example, the transmission and reception of the measurement value of the physical quantity measured only for a short period of time depletes the battery of the wireless sensor. In other words, the server device can use only the result of the frequency analysis of the measurement value for a certain short period of time.

[0088] Figure 1 is a diagram for illustrating a result of frequency analysis by a configuration according to a comparative example. Figure 1 An example of a wireless sensor according to a comparative example is shown, which transmits N0 consecutive measurement values within a time period TO. Thus, the wireless sensor according to the comparative example transmits a large number (N0) of consecutive measurement values within a certain time period TO to improve the resolution of frequency analysis, which alone can exhaust the battery power. In other words, in the configuration according to the comparative example, the server device can use only the result of frequency analysis of measurement values within a certain short time period.

[0089] Therefore, it would be helpful to enable the result of frequency analysis of measurement values measured by a battery-powered wireless sensor over a long time period to be used by another device.

[0090] <EMBODIMENT>

[0091] Hereinafter, embodiments of the present disclosure are described with reference to the accompanying drawings. In each of the drawings, components having the same configuration or function are denoted by the same reference numerals. In the description of the embodiments, repeated description of the same parts can be appropriately omitted or simplified.

[0092] (Analysis system)

[0093] Figure 2 is a diagram showing an example configuration of an analysis system 1 according to an embodiment. The analysis system 1 includes a wireless sensor 10 and a server device 20. The wireless sensor 10 and the server device 20 are communicatively connected with a network N including, for example, the Internet, an intranet, a mobile communication network, or the like.

[0094] The wireless sensor 10 measures, for example, a physical quantity such as acceleration, and transmits a measurement value of the physical quantity to the server device 20 through wireless communication. The wireless sensor 10 can be battery-powered. According to the present embodiment, the wireless sensor 10 is mounted on a measurement object, and measures acceleration of the measurement object. However, the physical quantity measured by the wireless sensor 10 is not limited to acceleration, but can be any physical quantity, for example, temperature, pressure, flow rate, or the like. The wireless sensor 10 collects measurement values of a physical quantity that changes over a long time period with respect to a state. The wireless sensor 10 transmits the measurement value of the physical quantity to the server device 20 via the network N, for example, by a communication method such as LoRa communication.

[0095] The server device 20 receives the measurement value of the physical quantity from the wireless sensor 10, performs frequency analysis such as Fourier transform, and then performs a prescribed process such as display processing.

[0096] In such a configuration, the wireless sensor 10 intermittently measures the physical quantity at fixed time intervals, and transmits the measured values of the physical quantity each time of measurement to the server device 20. Upon receiving the measured values of the physical quantity intermittently measured at fixed time intervals, the server device 20 combines the measured values as measured values continuously measured over time, and performs frequency analysis on the combined measured values (combination information). Thus, according to the present embodiment, it is possible to perform frequency analysis on data reflecting measured values measured over a longer period of time, as compared with the conventional configuration. The configuration according to the present embodiment makes it possible to perform more effective frequency analysis when the state of the measurement target changes over a long period of time.

[0097] (Wireless Sensor)

[0098] As shown in FIG. 1, the wireless sensor 10 includes a controller 11, a storage device 12, a measurer 13, a signal processor 14, and a communicator 15. The wireless sensor 10 is configured as, for example, a dedicated electronic device, but is not limited thereto, and some or all of the components can be configured as, for example, any general-purpose electronic device such as a field programmable gate array (FPGA). Figure 2

[0099] The controller (first controller) 11 includes at least one processor. According to the present embodiment, the “processor” can be, but is not limited to, a general-purpose processor or a dedicated processor specialized for a specific process. The controller 11 is communicatively connected to each component of the wireless sensor 10, and controls the overall operation of the wireless sensor 10.

[0100] The storage device 12 includes any memory module such as a read-only memory (ROM), a random access memory (RAM), and a solid state drive (SSD). The storage device 12 can be used as, for example, a main storage device, an auxiliary storage device, or a cache memory. The storage device 12 stores information used in the operation of the wireless sensor 10. For example, the storage device 12 can store information such as measured values of the measured physical quantity, and measurement times. The controller 11 and the storage device 12 can be configured integrally as a micro controller unit (MCU) or the like. The integrated configuration as the MCU or the like is not limited to the controller 11 and the storage device 12. For example, the wireless sensor 10 can be configured integrally as the MCU or the like with all or any part of the controller 11, the storage device 12, the measurer 13, the signal processor 14, and the communicator 15.

[0101] The measurer 13 is a sensor that measures a physical quantity related to the measurement target to obtain a measured value. The measurer 13 is, for example, an acceleration sensor, but is not limited thereto, and can be, for example, a temperature sensor, a pressure sensor, or a flow sensor.

[0102] The signal processor 14 analyzes a signal of the measured value of the physical quantity measured by the measurer 13. The following description is made with reference to​Figure 3 The signal processor 14 is described in detail.

[0103] The communicator 15 includes any communication module for wirelessly communicating with the server device 20 via the network N. According to the present embodiment, the communicator 15 is a communication module for LoRa communication, but is not limited to this type of wireless communication. For example, the communicator 15 can include a communication module for any wireless communication such as Bluetooth Ò (Bluetooth is a registered trademark of Japan, other countries, or both), near field communication (NFC), wireless local area network (LAN), and the like).

[0104] Some or all of the components of the wireless sensor 10 can be implemented by a dedicated circuit included in the controller 11. That is, some or all of the components of the wireless sensor 10 can be implemented by hardware. Alternatively, some or all of the components of the wireless sensor 10 can be implemented by executing a computer program (program) by a processor within the controller 11. That is, some or all of the components of the wireless sensor 10 can be implemented by software.

[0105] Figure 3 is a schematic view showing a detailed example configuration of some functional blocks of the analysis system 1 of Figure 2 In Figure 3 , components included in the signal processor 14 and the communicator 15 of the wireless sensor 10 are shown.

[0106] As shown in Figure 3 , the signal processor 14 includes a measurement value input section 141, an amplifier 142, a filter 143, a timing setter 144, and an A / D converter 145. The measurement value input section 141 obtains, via input from the measurer 13, a signal of a measurement value of a physical quantity obtained by the measurer 13. The amplifier 142 amplifies the signal of the measurement value obtained by the measurement value input section 141 at a predetermined amplification rate. The filter 143 performs frequency filtering processing on the signal of the measurement value amplified by the amplifier 142 and outputs a signal related to a predetermined frequency range of the measurement value. The A / D converter 145 converts the signal output from the filter 143 from an analog signal to a digital signal. The timing setter 144 sets the operation timing of the filter 143 and the A / D converter 145. Specifically, the timing setter 144 can set the sampling period of the A / D converter 145. The timing setter 144 can set the filter 143 to change the filter used according to the sampling period.

[0107] The communicator 15 includes a signal transmitter 151. The signal transmitter 151 transmits, to the server device 20, the signal of the measurement value in digital format output from the A / D converter 145 by LoRa communication.

[0108] For example, reference Figure 3 Each component included in the signal processor 14 and the communicator 15 is described as being composed of separate and independent hardware. Specifically, each component included in the signal processor 14 and the communicator 15 can be implemented as a separate functional block in an FPGA. Alternatively, each component included in the signal processor 14 and the communicator 15 can be implemented by software.

[0109] (Server device)

[0110] like Figure 2 As shown, server device 20 includes controller 21, storage device 22, input unit 23, output unit 24, and communicator 25. Server device 20 is implemented by a general-purpose computer such as a workstation (WS) or a personal computer (PC), but may also be an FPGA, dedicated electronic device, etc.

[0111] The controller (second controller) 21 includes at least one processor. The controller 21 is communicatively connected to each component of the server device 20 and controls the overall operation of the server device 20.

[0112] The storage device 22 includes, for example, any storage module such as a hard disk drive (HDD), an SSD, ROM, or RAM. The storage device 22 can function as, for example, a primary storage device, an auxiliary storage device, or a cache memory. The storage device 22 stores any information used in the operation of the server device 20. For example, the storage device 22 can store system programs, application programs, and various information received by the communicator 25. The storage device 22 is not limited to being built into the server device 20 and may also be an external database or external storage module. For example, the storage device 22 can store the measured values ​​of physical quantities received from the wireless sensor 10.

[0113] The input unit 23 includes at least one input interface that receives user input operations and obtains input information based on the user input operations. For example, the input unit 23 can be, but is not limited to, physical keys, capacitive keys, a pointing device, a touch screen integrated with the display of the output unit 24, etc.

[0114] The output unit 24 includes at least one output interface that outputs information to the user and notifies the user. For example, the output unit 24 may be, but is not limited to, a display that outputs information as images, a speaker that outputs information as sound, etc. Such a display may be, for example, a liquid crystal panel display, an electroluminescent (EL) display, etc. At least one of the input unit 23 and the output unit 24 may be configured as an integrated component of the server device 20, or may be provided as a separate unit.

[0115] The communicator 25 includes any communication module that can be connected to another device through any communication technology. The communicator 25 can also include a communication control module for controlling communication with another device and a storage module that stores data for communication, such as identification information required for communication with another device.

[0116] As Figure 3 shown, the communicator 25 of the server device 20 includes a signal receiver 251. The signal receiver 251 receives a signal of a measurement value transmitted from the wireless sensor 10 via the network N.

[0117] The controller 21 includes a data combiner 211 and an analyzer 212. The data combiner 211 accumulates and combines measurement values of a physical quantity measured intermittently at regular intervals. The analyzer 212 performs frequency analysis such as Fourier transform on a signal (combination information) of the measurement values combined by the data combiner 211.

[0118] The output 24 includes a display 241. The signal on which frequency analysis such as Fourier transform is performed in the analyzer 212 is displayed.

[0119] With reference to Figure 3 each component included in the controller 21 described above is implemented by software, for example. However, at least some components of the controller 21 can be implemented by dedicated hardware. For example, the display 241 of the output 24 and the signal receiver 251 of the communicator 25 are each constituted by hardware. However, at least some components included in the output 24 and the communicator 25 can be implemented by software.

[0120] (Operation of analysis system)

[0121] As described above, unlike the conventional frequency analysis method, in the analysis system 1 according to the present embodiment, the wireless sensor 10 intermittently measures data required for single frequency analysis and transmits it to the server device 20. The server device 20 performs frequency analysis on a combination of the measurement values intermittently received from the wireless sensor 10. Therefore, the server device 20 is able to obtain and use a result of frequency analysis that reflects measurement values obtained over a longer period of time than with the conventional frequency analysis method.

[0122] Figure 4 is a schematic diagram for illustrating Figure 2 and Figure 3 frequency analysis performed by the analysis system 1 according to the present embodiment. Here, frequency analysis performed by the configuration according to the comparative example is described with reference to Figure 1

[0123] LoRa Wide Area Network (LoRaWAN Ò ​(LoRaWAN is a registered trademark of Japan, other countries, or both)) is typical low power wide area (LPWA) communication, which requires approximately 400 ms of time on air transmission time to transmit 11 bytes of data. Here, the time on air transmission time that affects power consumption is considered, and the latency due to the duty cycle limitation that does not affect power consumption is not considered. For example, in the configuration according to the comparative example, when the sampling period of one measurement is To and the number of sampling points is No = 2048 points, and assuming that each measurement value is 2 bytes of information, the amount of data to be transmitted is 4096 bytes. As a result, the time on air transmission time T air0 is 149 s Figure 1 ). For example, it is assumed that the amount of power stored in the battery of the wireless sensor according to the comparative example is sufficient to perform communication of the time on air transmission time T air0 of 149 s. In this case, the server device according to the comparative example can use only the result of the frequency analysis reflecting the measurement values obtained in a short time of 2.048 s.

[0124] On the other hand, it is assumed that in the analysis system 1 according to the present embodiment, for example, the measurement interval is unchanged, the sampling period of one measurement to be obtained is ti = 0.064 s, the number of data points is ni = 64 points, and the information is 2 bytes per measurement value. In this case, the time on air transmission time of the measurement values from a single measurement is reduced to 4.7 s. It is assumed that the wireless sensor 10 repeats such measurement and transmission 32 times, for example, every t2 of 1 day (i.e., t2 = 1 day), and for each measurement, the measurement value is transmitted to the server device 20. In this case, the server device 20 accumulates and combines the measurement values to finally collect data, which is equivalent to å;ti = Ti = 2.048 s and å;ni = Ni = 2048 data points. In this case, the time on air transmission time T air1 = 4.7 s'32 = 149 s, which is the same as the time on air transmission time T air0 described in the configuration according to the comparative example. The power consumption of the wireless sensor 10 is proportional to the time on air transmission time. Therefore, assuming that the amount of power stored in the battery of the wireless sensor 10 in the analysis system 1 is the same as the amount of power stored in the battery of the wireless sensor of the comparative example, the server device 20 in the analysis system 1 is able to use the result of the frequency analysis reflecting the measurement values measured over 32 days. Therefore, the analysis system 1 according to the present embodiment, the server device 20 is able to cause another device to use the result of the frequency analysis of the measurement values measured over a longer period of time compared to the configuration according to the comparative example.

[0125] The measurement value data obtained by the server device 20 is incomplete, as Figure 4The waveform equivalent to the frequency analysis of the once-collected data can be obtained by applying a window function to the signal of the measured value of each sampling, then combining, and performing frequency analysis such as Fourier transform. The analysis of the analysis system 1 according to the present embodiment is more effective for a system in which the frequency of the measured value changes over a long period of time when observed due to a failure or the like, compared to a system in which the frequency of the measured value changes over a short period of time.

[0126] Figure 5 is a flowchart showing an example operation of the wireless sensor 10. Figure 2 The operation of the wireless sensor 10 described with reference to Figure 2 may at least partially correspond to the analysis method of the analysis system 1. The operation of each step in Figure 5 may be performed based on the control of the controller 11 of the wireless sensor 10.

[0127] In step S1, the controller 11 of the wireless sensor 10 determines a sampling rate and a measurement interval. Specifically, the controller 11 can determine the sampling rate and the measurement interval in response to a signal from an external device such as the server device 20 or an instruction from a user. The sampling rate is an interval at which a measured value is obtained at one measurement time tl. The measurement interval is an interval tl at which one measurement is performed.

[0128] In step S2, the controller 11 sets the A / D converter 145. Specifically, the controller 11 sets the operation timing in accordance with the sampling rate and the measurement interval tl, and the amplitude rate of the A / D converter 145, and the like. These settings can be determined in response to a signal from an external device such as the server device 20 or an instruction from a user.

[0129] The controller 11 performs each process from step S3 to step S6 for each measurement interval tl.

[0130] In step S3, the controller 11 controls the measurer 13 to measure a physical quantity of a measurement object. Specifically, the controller 11 measures the physical quantity at the measurement time tl at the sampling rate determined in step S1. In this way, the controller 11 obtains nl measured values.

[0131] In step S4, the controller 11 obtains a digital signal of the measured value of the physical quantity obtained in step S3. Specifically, the controller 11 converts an analog signal of the measured value of the physical quantity into a digital signal by the A / D converter 145 whose operation timing and the like are set in step S2.

[0132] In step S5, the controller 11 transmits the digitized measured value signal to the server device 20 through the signal transmitter 151.

[0133] At step S6, the controller 11 determines whether to end the processing. Specifically, the controller 11 can determine the end of the processing based on the elapse of a predetermined processing period, a user instruction to end the processing, or the remaining battery level becoming less than a predetermined threshold. When the processing is to be ended (Yes in step S6), the controller 11 ends the processing of the flowchart; otherwise (No in step S6), after the passage of the measurement interval t2, the controller 11 resumes the processing from step S3. Figure 5 At step S6, the controller 11 determines whether to end the processing. Specifically, the controller 11 can determine the end of the processing based on the elapse of a predetermined processing period, a user instruction to end the processing, or the remaining battery level becoming less than a predetermined threshold. When the processing is to be ended (Yes in step S6), the controller 11 ends the processing of the flowchart; otherwise (No in step S6), after the passage of the measurement interval t2, the controller 11 resumes the processing from step S3.

[0134] Figure 6 is a flowchart illustrating an example operation of the server apparatus 20 of Figure 2 Referring to the description of the server apparatus 20 of Figure 6 The operation of the server apparatus 20 described can correspond at least in part to the analysis method of the analysis system 1 or the control method of the server apparatus 20. The operation of each step in Figure 6 can be performed based on the control of the controller 21 of the server apparatus 20.

[0135] At step Sll, the controller 21 of the server apparatus 20 receives the measurement values of the physical quantity from the wireless sensor 10 via the network N. Specifically, the controller 21 receives n1 measurement values measured at the measurement time t1 of Figure 4 At step Sll, the controller 21 of the server apparatus 20 receives the measurement values of the physical quantity from the wireless sensor 10 via the network N. Specifically, the controller 21 receives n1 measurement values measured at the measurement time t1 of

[0136] At step S12, the controller 21 applies a window function to the n1 received measurement values. For example, the controller 21 can apply any window function, such as a Hamming window, a Hanning window, or a Blackman window, to the measurement values.

[0137] At step S13, the controller 21 accumulates each measurement value to which the window function is applied in steps Sll and S12 and combines these measurement values as time-continuous data. Specifically, the controller 21 repeatedly performs steps Sll and S12 to accumulate a preset number of measurement values required for frequency analysis in the storage 22. At step S13, the controller 21 combines n1 measurement values obtained at each measurement interval t2 accumulated in the storage 22 and obtains combined data as data continuously obtained over time.

[0138] At step S14, the controller 21 performs frequency analysis on the combined data obtained as time-continuous data in step S13. The controller 21 can perform the frequency analysis using any known method. The frequency analysis performed by the controller 21 is not limited to FFT or Fourier transform, such as STFT, but can also be, for example, a frequency filter.

[0139] In step S15, the controller 21 outputs the frequency data of the measurement value for which the frequency analysis is performed in step S14. For example, the frequency data can be saved in the storage device 22, or an image of the frequency data can be displayed on the display 241. Then, the controller 21 ends the processing of the flowchart. Figure 6

[0140] Referring to Figures 7 to 9 the effects of the analysis processing of the analysis system 1 shown in the Figures 4 to 6 explanation. Figure 7 is a schematic view showing an example of a signal to be analyzed. In Figure 7 , the curves 101 to 104 show examples of individual signals that represent the measurement values of the physical quantity before the application of the window function by the processing of step 12 at the server device 20. Each time period of 0s to 16s, 16s to 32s, 32s to 48s, and 48s to 64s corresponds to one measurement time tl. In other words, the curves 101 to 104 as a whole correspond to a combined signal of the physical quantity measured intermittently at fixed intervals without the application of the window function. Here, the curve 101 represents the change in the measurement value in the time period of 0 to 16s. The curve 102 represents the change in the measurement value in the time period of 16s to 32s. The curve 103 represents the change in the measurement value in the time period of 32s to 48s. The curve 104 represents the change in the measurement value in the time period of 48s to 64s. The curve 105 represents the change in the measurement value after the application of the window function to each of the time periods of 0 to 16s, 16s to 32s, 32s to 48s, and 48s to 64s with respect to the curves 101 to 104 connected together.

[0141] Figure 8 and Figure 9 shows Figure 7 the example of the signal shown in FIG. 10 after the Fourier transform is performed. In Figure 8 , the curve 201 is a curve representing the frequency component of the curve 101 obtained by performing the Fourier transform on the signal of the curve 101 of Figure 7 . The curve 202 is a curve representing the frequency component of the curve 102 obtained by performing the Fourier transform on the signal of the curve 102. The curve 203 is a curve representing the frequency component of the curve 103 obtained by performing the Fourier transform on the signal of the curve 103. The curve 204 is a curve representing the frequency component of the curve 104 obtained by performing the Fourier transform on the signal of the curve 104. In other words, the curves 201 to 204 represent the signals after the frequency analysis obtained according to the comparative example. However, in the configuration according to the comparative example, the signal after the frequency analysis obtained at the server device side by a single measurement is any one of the curves 201 to 204. For example, when the battery of the wireless sensor is depleted due to one measurement, the signal after the frequency analysis is the curve 201. In this case, the frequency component of the curve 201 is not the frequency component of the curve 102, but the frequency component of the curve 104.​Figure 1 and Figure 4 In the described example, according to the comparative example, the server device can use only one of the curves 201 to 204 .

[0142] on the contrary, Figure 9 The curve 205 in FIG. Figure 7 The frequency component of the curve 105 obtained by Fourier transforming the signal of the curve 105. As described above, the curve 105 is a combination of the curves 101 to 104 after applying the window function to each of the curves 101 to 104, so the curve 205 represents the signal after frequency analysis obtained by the analysis system 1 according to the present embodiment. Figure 8 Curves 201 to 204 in FIG. Figure 9 As can be clearly seen by comparing curve 205 in the example, curve 205 represents a waveform that reflects the distribution of frequency components across all of curves 201 to 204. Specifically, curve 205 has a waveform that allows the user to identify the global distribution of each peak frequency in curves 201 to 204. Therefore, according to analysis system 1, server device 20 can use the results of frequency analysis of measurement values ​​measured over a longer period of time, compared to the configuration according to the comparative example, in which wireless sensor 10 performs processing that consumes the same amount of power as the wireless sensor of the comparative example. In other words, in the configuration according to the comparative example, when the waveform being analyzed changes over a long period of time (e.g., daily or monthly), the server device can only obtain waveforms at various time points, making it impossible to perform analysis that includes waveform changes. In contrast, in analysis system 1 according to this embodiment, server device 20 can perform analysis that includes such long-term changes. Furthermore, in analysis system 1, server device 20 can obtain information such as the peak frequency and amplitude of each waveform obtained at various time points, as in the comparative example.

[0143] As described above, analysis system 1 includes wireless sensor 10 and server device 20, which are capable of communicating with each other. Wireless sensor 10 obtains measurement values ​​of a physical quantity of a measurement object measured at predetermined measurement times distributed at predetermined intervals, and transmits the obtained measurement values ​​to server device 20. Server device 20 combines the measurement values ​​of the physical quantity received from wireless sensor 10 at the predetermined measurement times distributed at predetermined intervals to obtain combined information representing a temporal sequence of these measurement values, performs frequency analysis on the combined information, and outputs the results of the frequency analysis of the combined information. In this way, analysis system 1 performs frequency analysis after combining the measurement values ​​of the physical quantity of the measurement object measured at the predetermined measurement times distributed at predetermined intervals. Consequently, another device on the server device can use the results of the frequency analysis of measurement values ​​measured over a longer period of time.

[0144] The server device 20 performs window function processing on each of the measured values of the physical quantity measured at the measurement times tl distributed at predetermined intervals, and combines the measured values on which the window function processing has been performed to obtain combination information (combined measured values). Thus, the window function is applied and then the measured values are combined to obtain the combination information, thereby contributing to prevention of error in the frequency components due to signal discontinuity.

[0145] In the analysis system 1 according to the present embodiment, by setting the measurement times tl to be longer times and using the window function over the longer times, it is possible to improve the resolution at low frequencies without changing the number of measured values (i.e., the power consumption of the wireless sensor 10).

[0146] In the analysis system 1, the number of measured values measured at a given time point is smaller than the number of measured values in the configuration according to the comparative example. As a result, the frequency range that can be analyzed can become narrow, and thus the server device 20 can not be able to acquire data in the frequency range desired to be analyzed. To avoid such a situation, the analysis system 1 can change the window width by downsampling (sampling again at a lower frequency) without changing the number of data points. Further, the number of transmission data (nl) transmitted from the wireless sensor 10 can be changed based on an instruction from the server device 20, so that the server device 20 is able to measure the frequency range desired to be analyzed. The window width information can be transmitted from the wireless sensor 10 to the server device 20, so that the server device 20 is able to perform analysis according to the window width.

[0147] In addition, the measurement interval t2 of the wireless sensor 10 can also be set from an external device such as the server device 20. That is, the server device 20 transmits a desired time interval to the wireless sensor 10. The wireless sensor 10 can use the time interval (measurement interval t2) received from the server device 20 as the predetermined interval to obtain measured values of the physical quantity. For example, the wireless sensor 10 including an accelerometer can be attached to a rotating machine such as a motor, and can perform frequency analysis of an integral multiple of the rotational speed of the rotating machine. Thus, when the frequency change occurring periodically is known in advance, the wireless sensor 10 can be set from the server device 20 or the like with a measurement interval corresponding to the period. In addition, the measurement interval t2 is not a fixed value but can be set to vary randomly within a certain range.

[0148] For example, the server device 20 can transmit a range of time intervals (e.g., upper and lower limits of a time range) to the wireless sensor 10, and the wireless sensor 10 can randomly determine a time interval t2 within the range each time the wireless sensor 10 obtains a measurement value of the physical quantity. Alternatively, the server device 20 can randomly determine a time interval t2 for each time interval t2 and instruct the wireless sensor 10 to use the determined time interval t2. For example, in order to capture a frequency change that occurs irregularly, it is possible to effectively analyze such a frequency change by setting the measurement interval t2 to be random.

[0149] In addition, in the above example, the window function processing is performed in the server device 20, but the window function processing can also be performed on the wireless sensor 10 side. In the case where the window function processing is performed by the server device 20, the rectangular window function processing can be performed on the wireless sensor 10 side.

[0150] Further, the server device 20 can combine waveforms of time series of received measurement values and display the result on the display 241 as shown by the curve 105 in Figure 7 without performing a frequency analysis process such as FFT. Further, the server device 20 can analyze a signal received from the wireless sensor 10 without performing a frequency analysis process such as Fourier transform.

[0151] When the server device 20 does not receive a sufficient number of measurement values for frequency analysis, the server device 20 can perform analysis by setting measurement values in intervals for which data is insufficient to a fixed value (e.g., 0) or a representative value (e.g., an average of measurement values received until then). For example, when measurement values of 32 measurement times t1 are to be collected to create data of time T1, but only 10 measurement values are received, the server device 20 can perform such a process. Further, the server device 20 can change the number of data points to be collected. For example, the server device 20 can combine 32 measurement values for analysis, and at the same time, also combine 8 measurement values for analysis.

[0152] Further, the wireless sensor 10 can be configured to be driven by an energy harvesting technology such as vibration power generation instead of a battery. Alternatively, the wireless sensor 10 can be any device connected to a stable power source but requiring low power consumption.

[0153] The present disclosure is not limited to the above-described embodiments. For example, a plurality of functional blocks shown in the block diagram can be integrated, or one functional block can be divided. Instead of being performed in a time sequence according to the description, a plurality of steps described with reference to the flowchart can be performed in parallel or in a different order according to the processing capacity of a device performing each step or as needed. Other changes are possible without departing from the spirit of the present disclosure.

[0154] List of reference signs

[0155] 1 analysis system

[0156] 10 wireless sensor

[0157] 11 controller

[0158] 12 storage device

[0159] 13 measurer

[0160] 14 signal processor

[0161] 141 measurement value input section

[0162] 142 amplifier

[0163] 143 filter

[0164] 144 timing setter

[0165] 145 A / D converter

[0166] 15 communicator

[0167] 151 signal transmitter

[0168] 20 server device

[0169] 21 controller

[0170] 211 data combiner

[0171] 212 analyzer

[0172] 22 storage device

[0173] 23 input section

[0174] 24 output section

[0175] 241 display

[0176] 25 communicator

[0177] 251 signal receiver

[0178] 101 to 105 curves

[0179] 201 to 205 curves

[0180] N network

Claims

1. An analysis system comprising a wireless sensor and a server device capable of communicating with each other, wherein: The wireless sensor includes a first controller configured to: obtaining measurement values ​​of a physical quantity of a measurement object measured at predetermined measurement times distributed at predetermined intervals; and sending the obtained measured value of the physical quantity to the server device via a first communicator, The server device includes a second controller configured to: combining the measurement values ​​of the physical quantities measured at the measurement times distributed at the predetermined intervals, received from the wireless sensors, to obtain combined information as time-continuous measurement values; performing a frequency analysis on the combined information; as well as A result of the frequency analysis of the combined information is output.

2. The analysis system according to claim 1, wherein The second controller of the server device is configured to perform window function processing on the measurement values ​​of the physical quantity measured at the measurement times distributed at the predetermined intervals, and combine the measurement values ​​on which the window function processing has been performed to obtain the combined information.

3. The analysis system according to claim 1 or 2, wherein The second controller of the server device is configured to send a time interval to the wireless sensor via a second communicator, and The first controller of the wireless sensor is configured to obtain the measured value of the physical quantity using the time interval received from the server device as the predetermined interval.

4. The analysis system according to any one of claims 1 to 3, wherein The second controller of the server device is configured to send a range of time intervals to the wireless sensor via a second communicator, and The first controller of the wireless sensor is configured to randomly determine a time interval within a range received from the server device each time the wireless sensor obtains the measurement value of the physical quantity, and obtain the measurement value of the physical quantity using the randomly determined time interval as the predetermined interval.

5. The analysis system according to claim 1 or 2, wherein: The second controller of the server device is configured to transmit a prescribed time to the wireless sensor via a second communicator, and The first controller of the wireless sensor is configured to obtain the measured value of the physical quantity using the prescribed time received from the server device as the measurement time.

6. The analysis system according to any one of claims 1 to 5, wherein: The second controller of the server device is configured to transmit the number of the measurement values ​​to be measured at the measurement time to the wireless sensor via the second communicator, and The first controller of the wireless sensor is configured to obtain as many measurement values ​​of the physical quantity at the measurement time as the number received from the server device.

7. An analysis method for an analysis system, the analysis system comprising a wireless sensor and a server device capable of communicating with each other, the analysis method comprising: The wireless sensor obtains a measurement value of a physical quantity of a measurement object measured at predetermined measurement times distributed at predetermined intervals; and transmitting the obtained measured value of the physical quantity to the server device; as well as The server device combines the measurement values ​​of the physical quantities measured at the measurement times distributed at the predetermined intervals, received from the wireless sensors, to obtain combined information as time-continuous measurement values; performs frequency analysis on the combined information; and outputs a result of the frequency analysis of the combined information.

8. A server device comprising a controller capable of communicating with a wireless sensor, the wireless sensor being configured to obtain measurement values ​​of a physical quantity of a measurement object at predetermined measurement times distributed at predetermined intervals, the controller being configured to: receiving the measurement from the wireless sensor; combining the measurement values ​​of the physical quantities measured at the measurement times distributed at the predetermined intervals, received from the wireless sensors, to obtain combined information as time-continuous measurement values; performing a frequency analysis on the combined information; as well as A result of the frequency analysis of the combined information is output.

9. A method for controlling a server device, the server device comprising a controller capable of communicating with a wireless sensor, the wireless sensor being configured to obtain a measurement value of a physical quantity of a measurement object at predetermined measurement times distributed at predetermined intervals, The controller receives the measurement values ​​from the wireless sensors; combines the measurement values ​​of the physical quantities measured at the measurement times distributed at the predetermined intervals, received from the wireless sensors, to obtain combined information as time-continuous measurement values; performs frequency analysis on the combined information; and outputs a result of the frequency analysis of the combined information.

10. A program for causing a computer capable of communicating with a wireless sensor to execute the following processing, wherein: The wireless sensor is configured to obtain measurement values ​​of a physical quantity of a measurement object at predetermined measurement times distributed at predetermined intervals: receiving the measurement value from the wireless sensor; a process of combining the measurement values ​​of the physical quantity received from the wireless sensor and measured at the measurement times distributed at the predetermined intervals to obtain combined information as time-continuous measurement values; performing a frequency analysis process on the combined information; as well as A process of outputting a result of the frequency analysis of the combined information.

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