JP2013036812A - Sensor network system and sensor output correction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform correction with suppressed power consumption concerning sensors arranged in multiple places.SOLUTION: A sensor network system includes: multiple sensor parts arranged in multiple places; a sensor output transmission part for transmitting outputs from the respective sensor parts; and a correction device 30 for correcting outputs from the sensor parts. The correction device 30 includes: a sensor output collection part 33 for receiving respective sensor outputs from the sensor output transmission part; an environment parameter information collection part 34 for collecting environment parameter information related to respective environment conditions that give influence on the respective sensor outputs; an influence characteristic storage part 32 for storing the characteristics of change in the respective sensor outputs with respect to the change of previously acquired environment parameters; and a correction calculation part 31 for correcting the respective sensor outputs on the basis of the influence characteristics stored in the influence characteristic storage part 32 after associating the respective sensor outputs with the respective pieces of environment parameter information.

Description

  The present invention relates to a sensor network system having a sensor output correction function for sensors installed at a plurality of locations and a center output correction method.

  In recent years, the sophistication of plant monitoring has made it possible to collect information by comprehensively setting measurement points using a wireless sensor network composed of a large number of sensor nodes, which is useful for diagnosis such as shortening maintenance periods and early detection of equipment abnormalities. It is assumed that

  In order to ensure the measurement accuracy of sensor nodes in remote locations and always perform accurate diagnosis, it is necessary to consider ambient temperature changes in the installation environment. The ambient temperature in the installation environment is affected by many factors, such as whether it is outdoor or indoor, and whether air conditioning is present.

  Because of these factors, the temperature change range reaches several tens of degrees, so that a measurement error increases due to drift of the mounted sensor due to temperature. As shown in Patent Document 1, there is a technology in which a temperature sensor is mounted in a sensor node and a measurement error due to temperature drift is corrected in the sensor node.

JP 2009-25012 A

  The technique described in Patent Document 1 is a correction method for an acceleration sensor.

  In the conventional application, information from the acceleration sensor is used. However, since a temperature sensor, a GPS receiver, and a vehicle speed sensor are used as a correction method, many circuits are mounted for correction.

  Since processing for calculating the correction amount from the reference temperature characteristic data is required, it is expected that the power consumption will increase when such a sensor node is mounted on the sensor node.

  On the other hand, in the method using a wireless sensor network, each sensor node needs to consider the influence of changes in the surrounding environment conditions that affect the sensor output, so the surrounding environment information is also captured, and the influence of the surrounding environment conditions Is transmitted as a sensor output from the sensor node.

  For this reason, the sensor node needs to memorize the change characteristics of the sensor output due to changes in ambient environmental conditions and perform a correction operation. For this purpose, a power source such as a battery having a capacity and a durability capable of withstanding long-term operation is required. Necessary.

  There are usually a large number of sensor nodes, and there are many cases where the transmission distances are various. Since the ambient environment information captured by each sensor node also varies depending on the measurement target and model of the sensor, the amount of power supplied to the sensor node is considerable. For this reason, suppression of power consumption becomes important.

  An object of this invention is to be able to correct | amend the power consumption suppressed about the sensor installed in multiple places.

  In order to achieve the above-described object, a sensor network system according to the present invention includes a plurality of sensor units installed at a plurality of locations, a sensor output transmission unit that transmits output from each of the sensor units, and a sensor unit. In the sensor network system comprising: a correction device that corrects an output; the correction device includes a sensor output collection unit that receives each sensor output from the sensor output transmission unit; and each environmental condition that affects each sensor output. Collected by an environmental parameter collection unit that collects related environmental parameter information, an influence characteristic storage unit that stores characteristics of changes in each sensor output with respect to changes in the environmental parameters acquired in advance, and the sensor output collection unit After associating each sensor output with each environment parameter information collected by the environment parameter collection unit, Based on the effects characteristics stored in the affected characteristic storage unit, and having a correction calculating unit that corrects the respective sensor output.

  Further, the sensor output correction method according to the present invention is a sensor output correction method for correcting the output of a plurality of sensor units installed at a plurality of locations, wherein the influence characteristic storage unit influences each environmental parameter that affects each sensor output. A step of storing characteristics, a step in which a sensor output transmission unit transmits the output of each sensor unit installed at a plurality of locations, a step in which an environmental parameter information collection unit collects environmental parameter information, and an environmental parameter information transmission A step of transmitting an output of the environmental parameter collection unit, a step of a sensor output collection unit of the correction device receiving each sensor output from the sensor unit, and an environmental parameter information collection unit of the correction device, Receiving each environmental parameter information from the environmental parameter information transmission unit; and the correction calculation unit of the correction device receives the received Based on the sensor output and the environmental parameter information, the step of associating the sensor output with the environmental parameter information, and the correction calculation unit based on the influence characteristic stored in the influence characteristic storage part, And correcting the output from each sensor unit.

  According to the present invention, it is possible to perform correction while suppressing power consumption.

It is a block diagram which shows the basic composition of 1st Embodiment of the sensor network system which concerns on this invention. It is a block diagram which shows the structure of the correction | amendment apparatus in 1st Embodiment. It is a figure which shows the example of the reference | standard characteristic of the sensor for demonstrating 1st Embodiment. It is a block diagram which shows the basic composition of 2nd Embodiment of the sensor network system which concerns on this invention. It is a figure which shows the example of the individual characteristic of each sensor. It is a figure which shows the example of the amount of offset explaining 3rd Embodiment of the sensor network system which concerns on this invention. It is a figure which shows the example of a change of a temperature characteristic. It is a block diagram explaining 4th Embodiment of the sensor network system which concerns on this invention. It is a time change figure of the amount of correction explaining a 4th embodiment.

  Hereinafter, an embodiment of a sensor network system according to the present invention will be described with reference to the drawings. Here, the same or similar parts are denoted by common reference numerals, and redundant description is omitted.

[First embodiment]
FIG. 1 is a block diagram showing a basic configuration of a first embodiment of a sensor network system according to the present invention.

  Hereinafter, correction related to an acceleration sensor will be described as a representative example. Moreover, the environmental parameter which is a factor influencing the measurement error of the acceleration sensor was set as temperature.

  Each acceleration sensor corresponds to each sensor node 21 in FIG. Hereinafter, the acceleration sensor is represented by a sensor node 21. In the method using the normal wireless sensor network 15, each sensor node 21 also captures ambient environment information that affects the sensor output, performs an operation for correcting the influence of the environment parameter information, and then performs each sensor node. Generally, it is transmitted as a sensor output from 21.

  On the other hand, the sensor node 21 in FIG. 1 includes a case where a sensor output is generated without performing such correction. Measurement data of each acceleration sensor is basically collected by wireless transmission, that is, by the wireless sensor network 15. Specifically, each sensor node 21 is wirelessly transmitted to the base station 23 and transmitted to the correction device 30 via the backbone network 27.

  The temperature measurement as the environmental parameter, that is, the thermometer 24 may be measured by the equipment provided in the equipment, but for example, the one used for temperature control in the air conditioning control system may be taken into the server 25 of FIG. Alternatively, temperature information may be collected as information that can be obtained via another wireless sensor network. Thus, the existing temperature information collecting means can be used. The form of the environmental parameter transmission unit 28 that is a data transmission means of the environmental parameter information may be wireless or wired.

  Also, temperature information such as outdoors can be obtained via the Internet 26. Measurement data and temperature information by each sensor node 21 are collected by the correction device 30.

  As described above, the sensor network system 10 is each sensor node 21, the wireless sensor network 15 that is a transmission unit thereof, the thermometer 24 for measuring environmental parameters, or other equipment and temperature information based on public data and its transmission means. And an environmental parameter transmission unit 28.

  FIG. 2 is a block diagram illustrating the configuration of the correction apparatus according to the present embodiment.

  As shown in FIG. 2, the correction device 30 includes a sensor output collection unit 33 that collects sensor outputs from the sensor nodes 21 corresponding to each acceleration sensor, and an environmental parameter information collection unit that collects temperature information from each thermometer 24. 34, an influence characteristic storage unit 32 that stores the influence characteristic of the environmental parameter on the sensor output as reference characteristic data, and a correction calculation unit 31.

  FIG. 3 is a diagram showing an example of the reference characteristic of the sensor for explaining the present embodiment. As shown here, the influence characteristic of the environmental parameter information on the sensor output, that is, the acceleration sensor output depending on the temperature is shown. It shows the correlation characteristics of errors. Thereby, it becomes possible to correct the measurement data of the acceleration sensor based on the temperature information.

  Based on each sensor output information collected by the sensor output collection unit 33 and each environment parameter information collected by the environment parameter information collection unit 34, the correction calculation unit 31 first selects which environmental parameter for each sensor output information. Correspondence of information corresponds. Then, the sensor output is corrected based on the influence characteristic of the environmental parameter information on the sensor output.

  The influence characteristic of the environmental parameter on the sensor output may be, for example, a characteristic based on a catalog value or an average value of each sensor for the same type of sensor.

  In a sensor node based on a normal wireless network, the influence characteristics of the environmental parameter information on the sensor output due to changes in ambient environmental conditions are stored, the sensor output is corrected based on the environmental parameter information, and output from the sensor node. For this arithmetic processing and the like, a power source such as a battery having a capacity and a durability capable of withstanding long-term operation is required.

  On the other hand, according to the present embodiment, the correction calculation is performed by the correction device 30, so that the correction calculation at each sensor node 21 is unnecessary. For this reason, it is not necessary to collect environmental parameters at each sensor node, the load at each sensor node 21 is greatly reduced, and correction can be performed while suppressing power consumption at each sensor node 21.

[Second Embodiment]
FIG. 4 is a block diagram showing the basic configuration of the second embodiment of the sensor network system according to the present invention. This embodiment is a modification of the first embodiment, and the configuration thereof is the same as that of the first embodiment except for the contents of the influence characteristic storage unit 32 of the correction device 30.

  FIG. 5 is a diagram illustrating an example of the individual characteristics of the sensor of each sensor node 21. As described above, even if the types of sensors are the same, the error characteristics with respect to temperature differ for each sensor.

  Thus, in detail, the influence characteristics are different for each sensor, and this point may be considered in the influence characteristic data as necessary. The influence characteristic storage unit 32 stores individual influence characteristic data corresponding to each sensor node 21 in the influence characteristic storage unit 32. The correction calculation unit 31 performs correction based on this.

  As described above, it is possible to further improve accuracy by performing correction based on individual influence characteristic data corresponding to each sensor.

[Third embodiment]
FIG. 6 is a diagram illustrating an example of an offset amount for explaining the third embodiment of the sensor network system according to the present invention.

  When there is a difference between the actual temperature and the collected temperature information because the acceleration sensor which is the sensor of the illustrated sensor node 21 and the acquisition location of the thermometer 24 are separated or a shield is present, etc. As shown in FIG. 6, the characteristic is calculated in advance, the offset amount is stored in the influence characteristic storage unit 32 of the correction device 30, and the correction calculation unit 31 corrects the offset amount by considering the offset amount in the influence characteristic data. It is possible to ensure accuracy. Note that the influence characteristic storage unit 32 may store the influence characteristic with the offset amount corrected.

  Further, when the correction amount calculated by the correction calculation unit 31 exceeds a predetermined value, a method of adding the offset amount may be used.

  FIG. 7 is a diagram illustrating an example of a change in temperature characteristics. For example, when the time axis of the figure is annual, it shows a change due to the season. As described above, even when temperature information around the sensor cannot be obtained at all, for example, the daytime and nighttime, the season, or the operating state of the equipment is grasped in advance, and the temperature characteristics of the sensor installation location as shown in FIG. Correction can be performed by calculating. Considering a case where some abnormality occurs in the system and temperature information cannot be acquired, stable operation is possible by combining a plurality of temperature information acquisition paths.

[Fourth Embodiment]
FIG. 8 is a configuration diagram for explaining a fourth embodiment of the sensor network system according to the present invention. As shown in the figure, by providing the correction device 30 with the correction history storage unit 35 for storing the correction amount history, the correction device 30 can be applied to traceability for confirming past information.

  FIG. 9 is a time variation diagram of the correction amount for explaining the present embodiment. The fact that the correction amount has increased remarkably indicates that the sensor output or environmental parameter information has changed significantly. For example, when the correction amount exceeds a predetermined value, such as when the environmental condition of the sensor of the sensor node 21 exceeds an environmental value that the sensor can withstand, the environmental condition changes or It is also effective to output an alarm notification signal from the correction device 30 to alert the administrator that either the sensor output or the environmental parameter information is abnormal.

[Other Embodiments]
As mentioned above, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. For example, the sensor output transmission means is not limited to wireless transmission, and may be a transmission method other than wireless transmission.

  Moreover, you may combine the characteristic of each embodiment. For example, redundancy may be ensured by using the environmental parameter collection method in each embodiment together.

  As a processing method when a plurality of values are obtained for the same environmental parameter, a method of taking an average value of these values, or a method of taking a maximum value or a minimum value of a plurality of values due to the nature of the sensor output can be considered. Moreover, you may use for abnormality determination by the deviation of a some value.

  In addition, these embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

10 ... Sensor network system 15 ... Wireless sensor network (sensor output transmission unit)
21 ... Sensor node (sensor part)
23 ... Base station 24 ... Thermometer (environmental parameter measurement unit)
25 ... Server 26 ... Internet 27 ... Core network 28 ... Environmental parameter transmission unit 30 ... Correction device 31 ... Correction calculation unit 32 ... Influence characteristic storage unit 33 ... Sensor Output collection unit 34 ... environmental parameter information collection unit 35 ... correction history storage unit

Claims (10)

A plurality of sensor units installed at a plurality of locations;
A sensor output transmission unit for transmitting an output from each of the sensor units;
A correction device for correcting the output from the sensor unit;
In a sensor network system comprising:
The correction device includes:
A sensor output collection unit for receiving each sensor output from the sensor output transmission unit;
An environmental parameter collection unit that collects environmental parameter information related to each environmental condition affecting each sensor output;
An influence characteristic storage unit that stores characteristics of changes in each sensor output with respect to changes in the environmental parameters acquired in advance;
After associating each sensor output collected by the sensor output collection unit with each environmental parameter information collected by the environmental parameter collection unit, the influence characteristic stored in the influence characteristic storage unit Correction operation unit for correcting each sensor output,
A sensor network system comprising: The sensor network system further includes an environmental parameter measurement unit that measures the environmental parameter information, and an environmental parameter transmission unit that transmits environmental parameter information measured by the environmental parameter measurement unit,
The environmental parameter collection unit collects signals from the environmental parameter measurement unit;
The sensor network system according to claim 1. The influence characteristic storage unit further stores preliminarily measured ambient environment preliminary information,
The correction calculation unit further corrects each sensor output using the ambient environment preliminary information stored in the influence characteristic storage unit;
The sensor network system according to claim 1.   The sensor network system according to claim 1, wherein the sensor unit is a sensor node, and the sensor output transmission unit includes a wireless network.   The sensor network system according to any one of claims 1 to 4, wherein the influence characteristic storage unit stores unique characteristic data regarding each sensor unit. The influence characteristic storage unit further stores a predetermined offset amount,
When the environmental parameter information used for correcting each sensor output has a difference of a predetermined value or more with respect to an actual ambient environment condition, the correction calculation unit calculates the predetermined offset amount as the ambient environment. Adding to information,
The sensor network system according to any one of claims 1 to 5, wherein:   7. The correction operation unit collects a plurality of pieces of environmental parameter information for the same sensor output, and corrects the sensor output by combining these information. 8. The sensor network system described in 1.   The sensor network system according to any one of claims 1 to 7, wherein the correction device includes a correction history storage unit that individually stores a correction amount history for each sensor output.   The said correction | amendment apparatus emits the alarm output to the effect that it is abnormal when the corrected amount of each said sensor output exceeds a predetermined threshold value, The Claim 1 thru | or 8 characterized by the above-mentioned. The described sensor network system. In the sensor output correction method for correcting the output of the sensor unit installed in a plurality of places,
An influence characteristic storage unit storing an influence characteristic of each environmental parameter affecting each sensor output;
A step in which the sensor output transmission unit transmits the output of each sensor unit installed at a plurality of locations;
An environmental parameter information collection unit collecting environmental parameter information;
An environmental parameter information transmission unit transmitting the output of the environmental parameter collection unit;
A sensor output collection unit of the correction device receiving each sensor output from each sensor unit; and
An environmental parameter information collection unit of the correction device receiving each environmental parameter information from the environmental parameter information transmission unit;
A step of causing the correction calculation unit of the correction device to associate the sensor outputs with the environmental parameter information based on the received sensor outputs and the environmental parameter information;
The correction calculation unit correcting the output from each sensor unit based on the influence characteristic stored in the influence characteristic storage unit;
A sensor output correction method comprising:

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