KR20220063779A - Apparatus for determining the wind speed and direction using FBG sensor - Google Patents

Abstract

The present invention relates to a wind speed and wind vane capable of detecting wind strength and wind direction using a fiber bragg gratings (FBG) sensor for which is an optical fiber sensor. A device for measuring wind direction and wind speed using an FBG sensor comprises: a frame of a square pipe shape; a measuring part; and a fiber optic.

Description

{Apparatus for determining the wind speed and direction using FBG sensor}

The present invention relates to a wind speed and a wind vane capable of detecting the strength and direction of a wind using a Fiber Bragg Gratings (FBG) sensor, which is an optical fiber sensor.

In general, a windmill type wind direction anemometer is used as a device for measuring wind direction and wind speed.

This windmill type wind direction anemometer uses the principle that the rotational speed of the wind is proportional to the wind speed, and has a structure in which the windmill is attached to the tip of a streamlined body with vertical tail blades.

In addition, the windmill type wind direction anemometer is configured to mount a small generator of direct current or alternating current on a rotating shaft of the windmill, and measure the wind speed through the electromotive force generated by the small generator.

In addition, the windmill type wind direction anemometer is configured to measure the wind direction by detecting the rotational position of the wind direction anemometer according to the wind direction, so that the structure is complicated.

Meanwhile, unlike the method using a windmill, a strain gauge type wind direction and wind speed measuring device that detects an electrical resistance value linked when an elastic plate is deformed according to the strength and direction of wind is published in Korean Patent Office Registration No. 10-1168568 has been

However, these wind direction and wind speed measurement methods are all methods of detecting electrical signals, and due to the nature of the method to be installed to be exposed to the outside, the measurement accuracy may be deteriorated due to the influence of electrical noise generated from the outside. There is a disadvantage that damage or breakage of parts may occur.

Document 1. Korean Intellectual Property Office Registration Patent Publication No. 10-1168568, "Wind direction and wind speed measuring device" Document 2. Korean Patent Office Laid-Open Patent Publication No. 10-2018-0052962, "Measuring device using optical fiber grating sensor" Document 3. Korean Patent Office Laid-Open Patent Publication No. 10-2017-0021583, “Wind speed and wind direction sensor using optical fiber grid” Document 4. Korean Intellectual Property Office Registration Patent Publication No. 10-1600573, "Fiber-optic Bragg grating-based sensor and observation system using the same"

The present invention has been devised to solve the above problems, and it is to provide a measuring device that can measure the wind direction and wind speed using an optical signal and accurately measure the wind direction and wind speed using an FBG sensor with a simple structure. It is an object of the present invention.

In order to achieve the above object, the wind direction and wind speed measuring apparatus according to the present invention includes a frame 101 having a cross section of a square pipe shape; A sensing sphere 111 installed in the hole 104 of the frame 101 and displaced in the horizontal direction, one side is fastened to each of the sensing spheres 111 and the other side is a sensing sphere fastened to a non-displaced structure ( 111) is composed of an FBG sensor 113 that receives a tensile force according to the displacement of the measuring unit 110, which is installed on each of the four sides of the frame 101; and an optical fiber connected to the FBG sensor 113 to communicate the incident beam and the reflected beam.

At this time, the FBG sensor 113 is fastened with the spring 112 fastened to the non-displaceable structure, so that it is configured to receive the tensile force of the spring 112 elasticity according to the displacement of the sensing device 111 .

In addition, the spring 112 is characterized in that it is configured to be able to adjust the elasticity.

In addition, the guide (105) for guiding the horizontal slide movement of the detection tool (111); characterized in that it is configured to further include.

In addition, the sensing devices 111 installed on the four sides of the frame 101 are installed to face the north, the east, the south, and the west, respectively.

In addition, the photodetector for receiving the reflected beam transmitted from each of the measuring unit (110); and a calculation unit that calculates and processes wind speed and wind direction based on the wavelength change in each measurement unit 110 detected by the photodetector.

In the present invention configured as described above, by measuring the wind direction and wind speed with an optical signal using the FBG sensor, the restrictions on the installation environment are greatly alleviated and accurate measurement values can be obtained because there is no external electrical influence.

In addition, since the structure is simple, there is an advantage that production, maintenance and repair are very easy.

1 and 2 are views for explaining the wavelength change measurement principle using the FBG sensor.
Figure 3 is a perspective view showing a wind direction and wind speed measuring device according to the present invention.
Figure 4 is a view showing the internal structure of the wind direction and wind speed measuring apparatus according to the present invention.
5 is an enlarged view of a measuring unit of the measuring device;
6 is a view illustrating a state in which wind speed is measured by any one measuring unit.
7 and 8 are views illustrating a state in which the wind direction and wind speed are measured by the measuring device.
9 is a view showing wavelengths detected by each measuring unit of the measuring device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to preferred embodiments of the present invention and the accompanying drawings.

When it is said that any one component "includes" another component in the detailed description or claims of the invention, it is not construed as being limited to only the component, unless otherwise stated, and other components are not It should be understood that more may be included.

As used herein, terms such as "upper", "lower", "bottom", "front", "rear", "below", etc. are merely for facilitating description of the components as shown in the drawings. refers to orientation.

FBG (Fiber Bragg Gratings) is made in a periodic pattern by exposing a single-mode optical fiber core to ultraviolet light, and is made in the transverse direction of the beam. The portion exposed to ultraviolet light increases the refractive index of the optical fiber core, and this portion is called a grating.

The optical fiber grating is used to measure the size of the external temperature, strain, pressure, and other physical quantities applied from the wavelength change of the optical signal reflected from the optical fiber grating to the incident optical signal according to the change in temperature or strain.

The basic concept of the measuring device according to the present invention is to fix the FBG sensor 10 to the fixture 12 that is not affected by external influences, as shown in FIG. 1, and fasten the spring 13 to the end of the FBG sensor 10, The spring 13 is fastened to the position variable sphere 14 that physically responds to external influences.

The spring 13 applies a certain elasticity to the FBG sensor 10 and when the position variable ball 14 is displaced (for example, the position variable ball 14 changes from position ② to position ①), the FBG sensor ( The elasticity of the spring 13 acting on 10) is changed.

Due to the change in elasticity of the spring 13 acting on the FBG sensor 10, tension or compression occurs in the FBG sensor 10 and the period of the grating changes, so the wavelength of the light signal reflected from the grating of the FBG sensor 10 is also 2, and the photodetector and calculation unit of the measuring device (not shown) analyzes this and measures the external force (wind speed) that displaces the variable position sphere 14 .

The wind direction and wind speed measuring apparatus using the FBG sensor according to the present invention uses the same principle as described above, and as shown in FIG. 3 , the frame 101 is formed in a hexahedral shape, and the front, rear, and left sides are excluded except for the upper and lower surfaces. , and the right four sides constitute a measuring unit 110 that can measure the wind speed, respectively.

The measurement units 110 formed on four surfaces of the frame 101 operate as an ipsilateral measurement unit 110_E, a west measurement unit 110_W, a southern measurement unit 110_S, and a north side measurement unit 110_N, respectively.

To this end, when the measuring device 110 is installed, the ipsilateral measuring unit 110_E faces the ipsilateral side, the west measuring unit 110_W faces the west side, the south measuring unit 110_S faces the south side, and the north measuring unit 110_N faces the south side. Install to face north.

The measuring unit 110 constituting each of the ipsilateral measuring unit 110_E, the west measuring unit 110_W, the south measuring unit 110_S, and the north measuring unit 110_N is configured as shown in FIG. 5 .

The detection tool 111 is inserted into the hole 104 formed in the frame 101 .

The sensing sphere 111 is easily moved in the horizontal direction by the wind, which is an external force. For this purpose, the sensing sphere 111 is preferably formed of a material having a very light weight so that it can be easily displaced.

And the detection unit 111 is fastened with one end of the FBG sensor 113 and a fixture 114 , and the other end of the FBG sensor 113 is fixed to a structure (eg, the present invention) through a spring 112 . of the frame 111).

The structure for fastening and fixing the FBG sensor 113 through the spring 112 means a part that does not move when the wind blows, that is, when an external force is applied, such as the frame 101 or the ground.

The measuring unit 110 configured as described above operates as follows.

When the wind blows, the detection tool 111 slides inside the frame 101 by wind pressure, and the FBG sensor 113 coupled to the detection tool 111 with the fixture 114 interlocks with the detection tool 111 to It slides inside the frame 101 .

At this time, by installing the guide 105 so that the sensing sphere 111 can slide accurately only in the horizontal direction by the wind pressure, the sensing sphere 111 moves only in the horizontal direction by the wind pressure to accurately measure the measured value. It is preferable to configure it so that it can be obtained.

Since the guide uses several conventional guides (eg, LM guides, etc.) for guiding the slide movement, a detailed description thereof will be omitted.

When the FBG sensor 113 slides inside the frame 101 and is displaced, a tensile force is applied to the FBG sensor 113 by the spring 112, and by the change of the period of the grid of the FBG sensor 113 to which the tensile force is applied The wavelength of the beam incident from the optical fiber 115 changes, and the photodetector (not shown) measures the change in the wavelength of the beam reflected from the FBG sensor 113, calculates it in the calculator, and slides the detection tool 111 Calculate the wind speed of the

When the wind blows in the vertical direction with respect to the sensing sphere 111 of the measuring unit 110 as shown in (a) of FIG. 6 , the measured wind pressure is all measured as the wind speed. ), if the wind blows in the direction inclined by the angle θ, it is measured as “wind speed × sinθ” in this measurement unit.

As shown in FIG. 6(b), the wind speed and wind direction of the wind blowing at an angle inclined at a predetermined angle with the sensing device 111 are measured and calculated together with one measuring unit 110 and another neighboring measuring unit 110. Wind speed and direction can be measured. This will be described in detail later.

In the measuring device 100 according to the present invention, as shown in FIG. 4 , the holes 104 are formed on each of the four sides of the frame 101 having a rectangular cross section, and the measuring units 110 are installed in each of the four holes.

At this time, the sensing devices 111 of each measuring unit 110 should be installed to face the east, west, south, and north directions, respectively.

As described above, the measuring unit 110 installed in the east, west, south, and north directions includes an ipsilateral measuring unit 110_E, a west measuring unit 110_W, a southern measuring unit 110_S, and a north measuring unit 110_N, respectively. .

And each optical fiber 115 connected to the FBG sensor 113 of the ipsilateral measuring unit 110_E, the west measuring unit 110_W, the south measuring unit 110_S, and the north measuring unit 110_N is connected to the coupler 102 through the coupler 102. It is connected to the optical fiber 103 that is connected to a light detection unit (not shown).

The beam incident through the optical fiber 103 is incident on the optical fiber 115 of the ipsilateral measuring unit 110_E, the west measuring unit 110_W, the south measuring unit 110_S, and the north measuring unit 110_N through the coupler 102 . The beam reflected from the grating from the FBG sensor 113 (the reflected beam is reflected by changing the wavelength as shown in FIG. 9) is transmitted through the optical fiber 103 through a photodetector (not shown) and a calculator (not shown). The wind speed and direction are measured and calculated.

7 is a state in which the north wind is blowing toward the measuring device 100 according to the present invention.

At this time, the detection sphere 111 of the ipsilateral measurement unit 110_E, the western measurement unit 110_W, and the southern measurement unit 110_S does not slide in the horizontal direction, but the detection sphere 111 of the northern measurement unit 110_N. Only the frame 101 slides inside.

Accordingly, since the sensing spheres 111 of the ipsilateral measuring unit 110_E, the west measuring unit 110_W, and the south measuring unit 110_S do not slide, their incident optical signals are received by the photodetector without a change in wavelength.

In addition, the optical signal incident to the northern measuring part 110_N while only the detection sphere 111 of the northern measuring part 110_N slides and moves, the wavelength is changed and detected by the optical detecting part.

There is no change in the wavelength of the incident beam in the other measuring units, and only the northern measuring unit 110_N detects the change in the wavelength of the incident beam, and the calculating unit determines that the current wind direction is the north wind, and the wind speed at this time is as follows.

Wind speed = k × Δλ_N

The Δλ_N is a change in wavelength in the northern measuring unit 110_N, k is a proportional constant, and is a proportional constant that reflects the characteristics of the spring 112 and friction when the position of the sensing surface 111 changes.

8 is a state in which the northeast wind is blowing toward the measuring device 100 according to the present invention.

In this state, a change in wavelength is measured in the north measurement unit 110_N and the ipsilateral measurement unit 110_E. Since there is a change in wavelength at the north side measuring unit 110_N and the ipsilateral measuring unit 110_E at the same time, the calculating unit determines that it is a northeast wind, and the wind speed at this time is as follows.

Wind speed = k × (Δλ_N + Δλ_E)

Wherein, Δλ_N is a change in wavelength in the northern measuring unit 110_N, Δλ_E is a change in wavelength in the ipsilateral measuring unit 110_E, and the proportional constant k is a proportional constant. It is a proportional constant that reflects friction when the position changes.

In addition, when the wind direction is precisely measured like the north-northeast wind, the precise wind direction can be measured by comparing the magnitude of each wavelength change in the north measuring unit 110_N and the ipsilateral measuring unit 110_E.

In addition, when the wind stops, the sensor 111 returns to the initial position due to the elasticity of the spring 112 .

The spring 112 constituting the measurement unit 110 may be configured to adjust the elasticity of the spring 112 according to the environment of the place where the measurement device 100 is installed by configuring the spring 112 with an adjustable elasticity. .

In the present invention configured as described above, by measuring the wind direction and wind speed with an optical signal using the FBG sensor, the restrictions on the installation environment are greatly alleviated and accurate measurement values can be obtained because there is no external electrical influence.

On the other hand, since the grating period of the FBG is generally changed by temperature, correction is required. However, in the present invention, since four sensors are used and the four sensors are under the same temperature change condition, temperature correction is not necessary.

In addition, since the structure is simple, there is an advantage that production, maintenance and repair are very easy.

The technical idea of the present invention has been reviewed through the above-described embodiments.

It is apparent that those of ordinary skill in the art to which the present invention pertains can variously modify or change the above-described embodiments from the description of the present invention.

In addition, even if not explicitly shown or described, a person of ordinary skill in the art to which the present invention pertains may make various modifications including the technical idea according to the present invention from the description of the present invention. is self-evident, which still falls within the scope of the present invention.

The above embodiments described with reference to the accompanying drawings have been described for the purpose of explaining the present invention, and the scope of the present invention is not limited to these embodiments.

100: measuring device
101: frame
102: coupler
103: optical fiber
104: Hall
105: guide
110: measurement unit
110_E: ipsilateral measurement part
110_W : West Measuring Unit
110_S : South measurement part
110_N: North measurement part
111: detection sphere
112: spring
113: FBG sensor
114: fixture
115: optical fiber

Claims (6)

Frame 101 in the form of a square pipe in cross section;
A sensing sphere 111 installed in the hole 104 of the frame 101 and displaced in the horizontal direction, one side is fastened to each of the sensing spheres 111, and the other side is fastened to a structure that does not displace ( 111) is composed of an FBG sensor 113 that receives a tensile force according to the displacement of the measuring unit 110, which is installed on each of the four sides of the frame 101; and
An optical fiber connected to the FBG sensor 113 to communicate the incident beam and the reflected beam;
According to claim 1,
Wind direction using the FBG sensor, characterized in that the FBG sensor 113 is configured to receive the tensile force of the spring 112 elasticity according to the displacement of the sensing device 111 by being engaged with the spring 112 fastened to the non-displaceable structure. and wind speed measuring devices.
3. The method of claim 2,
The spring 112 is a wind direction and wind speed measuring device using an FBG sensor, characterized in that configured to be able to adjust the elasticity.
According to claim 1,
A wind direction and wind speed measuring apparatus using an FBG sensor, characterized in that it further comprises; a guide (105) for guiding the horizontal slide movement of the detection unit (111).
According to claim 1,
The wind direction and wind speed measuring apparatus using the FBG sensor, characterized in that the detection ports 111 installed on the four sides of the frame 101 are installed to face the north, the east, the south, and the west, respectively.
According to claim 1,
a photodetector for receiving the reflected beam transmitted from each of the measuring units 110; and
Wind direction and wind speed measuring apparatus using an FBG sensor, characterized in that it further comprises; a calculation unit for calculating and processing wind speed and wind direction based on the wavelength change in each measuring unit 110 detected by the photodetector.

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