KR101938973B1 - Forest Fire Alarm System based on On-site Measurement of Fallen Leave Water Content - Google Patents

Abstract

The present invention is installed on a forest a method and to an apparatus using the same, four spring and the load cell, the load cell signal converter in an iron frame structures of about 1m ² to measure the weight of the leaves to the measuring litter weight And the invention was constructed using a weight calculation and recording device. Because it is easy to calibrate each load cell in the field, it is possible to calibrate the signal to collect more accurate signals. The signal collecting and storing device measures and stores the weight of the litter layer and calculates the moisture content. When the value is low, Characterized by a device for displaying an alert warning that there is a risk.

Description

{Forest fire alarm system based on on-site measurement of fallen leaves moisture content based on field measurement}

The present application relates to a measurement method for monitoring the risk of forest fires by calculating the weight of litter layer and water content of litter layer, which are important factors in the field of forest science, and a measurement apparatus using the same.

Forest fires are natural disasters that cause human and property losses as well as loss of forest resources created through forestation after the Korean War. In Korea, 64% of the country is covered with forests and access to forests is easy. Most of the forest fires since the 1990s are caused by human factors such as incidents and incineration of rice paddies. In order to prevent forest fires, forest fires are monitored intensively at the national level, such as the setting of prohibited periods of forest fires, the prohibition of forest fires, and the prohibition of incineration of rice paddies. However, Is not shrinking. Especially, in case of strong wind accompanied by dry spring around the coastal area, the damage to the large - scale forest fires is serious due to the spoils. Therefore, the necessity of means for predicting the spread of forest fires is increasing.

Measuring moisture changes in the surface of litters and soils in forests provides valuable information for determining the degree of water retention and the tendency for moisture to decrease during drying. In particular, sensing the weight fluctuation and surface permeation flux according to the moisture content of the forest soil surface layer including the leaves can be used to detect the risk of forest fires due to forest drying and the risk of landslide due to heavy rainfall.

On the other hand, in the prior art, the water content of the soil was measured through a measuring method and apparatus for measuring the water content of the soil.

In JP-A-1998-279353 ("Method and Apparatus for Measuring Moisture Content of Construction Soil", hereinafter referred to as "Prior Art 1"), existing flexibility values and existing weight values corresponding to soil water content values are stored as existing data, Discloses a water content measurement method and apparatus for calculating the water content of a soil by comparing the flexibility value and the weight value measured by detecting the resistance when the soil collected in the tank is stirred with the existing data.

In Korean Patent No. [10-1431190] ("Apparatus for Measuring Moisture Change in Soil Layer and Method for Measuring Moisture Change Using It," Prior Art 2), a soil layer sample is inserted into an inner vessel portion, There is disclosed a soil moisture measurement device for measuring soil moisture content change and water content increase and measuring a water content change and rainfall penetration depth of a soil layer sample and a moisture change measurement method using the same.

In Korean Patent No. 10-1326596 ("Water Content Measurement Apparatus", Prior Art 3), there is provided a method of measuring the amount of water used for cultivation of crops using a pedestal, scale, indicator, A moisture content measuring apparatus for effectively measuring a water content and a drainage amount is disclosed.

Conventionally, techniques for measuring the water content of various soils have been disclosed. However, in the prior arts 1 and 3, methods for measuring the water content of soil and litter are listed, There is a problem in that it is not possible to prepare the forest fire in advance because there is no apparatus that can do this.

In addition, the conventional weighing device for litter size was often constructed in a small size between 0.3m and 0.5m in diameter. This is because, as the size of the weighing apparatus increases, the load cell having a high measuring range must be used. However, when the load cell satisfying the maximum load condition considering the self-weight of the frame is used while increasing the size of the apparatus, There is a problem in that a load cell having an excess performance is needed.

Reference herein to any reference in the present application does not permit that the reference is related to the present application.

Prior art literature

- Patent literature

(Patent Document 1) Japanese Laid Open Patent Application (JP 1998-279353)

(Patent Document 2) Korean Registered Patent [10-1431190]

(Patent Document 3) Korean Registered Patent [10-1326596]

In order to solve the above-mentioned problem, the present invention provides four springs, a load cell, and a load cell signal converter connected to an iron frame structure of about 1 m ² to measure the weight of litter and soil, The invention was constructed using a calculation and recording device. The signal collection and storage device is intended to measure and store the weight of the loaded litter and to calculate the water content so that it is possible to recognize the forest fire in advance and prevent it in advance .

In addition, in the present invention, a spring is used to primarily support the self-weight of the frame and to adjust the horizontal load to eliminate the measurement range due to the self-weight of the frame, and the weight load by the second- The purpose of this measurement structure is to develop.

In addition, in the present invention, it is possible to accurately collect signals in the field by using a two-point normalization method so that calibration can be easily performed for each load cell.

In order to solve the above-mentioned problems, according to the present invention, there is provided a floor structure (100), comprising: a loading unit (110) made of a metal material and capable of containing leaves and forest soil layers; Four measurement substructures 140 installed at the respective central portions of the floor structure 100; A load cell 180 connected to the loading unit 110; A spring 190 connecting the loading part 110 and the measuring part structure 140; A screw 170 connecting the loading unit 110 and the load cell 180; A signal storage device 150 connected to the load cell 180 in a wire or wireless manner to receive the electrical signal of the load cell and use it as weight data to calculate and store the amount of water in each time slot; And an output unit 160 for outputting a warning message to the LCD when the water content of the litter and the soil layer falls to 5% or less by displaying the weight, moisture content, and fire risk information of the litter layer through the signal storage device 150 .

The mounting portion 110 is made of a metal material and has a width of 500 mm to 1000 mm, a length of 500 mm to 1000 mm, and a height of 150 mm to 200 mm.

In the bottom part of the loading part 111, a wire net supporting structure 130 having a width of 30 mm to 32 mm and a thickness of 2.0 mm to 2.5 mm is used, which is made of a wire net 120 having a grid between 10 mm and 20 mm. The wire net support structure 130 is characterized by using a cross-shaped structure to prevent deflection of the wire net.

In addition, the spring 190 is deformed by the load of the loading unit 110 to be in an equilibrium state.

Further, the screw 170 attached to the load cell 180 may be rotated to adjust the balance state of the loading unit 110.

In addition, the signal storage device 150 corrects sensitivity and signal drift phenomenon of the load cell through a two-point normalization method using two standard weights, and stores the electrical signal output from the load cell 180 do.

The present invention can provide important model data for the forest evapotranspiration model in the forest science field when measuring the weight of the litter layer in real time.

The weight of the litter can be used to calculate the water content of the litter, which can directly calculate the fire risk index in real time. Conventional wildfire risk indices are indirectly calculated based on the amount of evapotranspiration modeled by precipitation and irradiation in a forest fire prediction agency. However, the present invention has an advantage that continuous and direct calculation of the forest fire risk index becomes possible.

In addition, it is easy to calibrate for each load cell, so it is easy to calibrate the signal and it is possible to collect more accurate signals, so that it is possible to measure the signal directly on the spot.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an embodiment of an apparatus for measuring moisture content of leaves and soils according to an embodiment of the present invention; FIG.
FIG. 2 is a perspective view of an apparatus for measuring moisture content of litters and soil according to an embodiment of the present invention.
Figure 3 shows a signal acquisition and storage arrangement.
Figure 4 shows a micro board signal connection terminal for device signal acquisition and transmission.
FIG. 5 shows a flow chart of a declining moisture content fire alarm algorithm according to an embodiment of the present invention.
FIG. 6 shows an output section indicating the degree of fire risk according to weight, moisture content, and water content of leaves and soils.

Hereinafter, the present application will be described in detail by way of examples according to the present application, but the scope of the present application is not limited by the following embodiments. The embodiments of the present invention are provided to enable those skilled in the art to more fully understand the present invention.

When an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, but other elements may be present in the middle It should be understood. On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it will be understood that no other element exists in between.

  Other expressions that describe the relationship between components, such as " between "or" neighboring to "and" directly adjacent to "

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises" or "having" and the like are intended to specify that there are performed features, numbers, steps, operations, elements, parts or combinations thereof, and that one or more other features But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, parts, or combinations thereof.

FIG. 1 is an embodiment of an apparatus for measuring moisture content of leaves and soil according to an embodiment of the present invention, and FIG. 2 is a perspective view of an apparatus for measuring moisture content of leaves and soil according to an embodiment of the present invention. 1 and 2, the apparatus for measuring soil moisture and soil moisture content according to an embodiment of the present invention includes a bottom structure 100, a loading unit 110, a load cell unit 180, and a signal storage device 150 .

As a preferred example, the bottom of the loading part 110 is wrapped with polyethylene, the water is collected at the center under the structure, the tube is connected, and a nonwoven fabric is installed on the wire net so as not to lose the soil.

The 50 N class load cell 180 was selected assuming that the expected range of weight of the fallen leaves and soil surface to be loaded was 5 kg in the dry state and 15 kg in the wet state and 4 pieces were placed in the center of each side of the floor structure 100 In order to offset the weight of the iron structure before litter and soil application, the coil spring 190 is attached to the side of the attachment point of the load cell 180, and the load supporting degree of the spring 190 is adjusted through the screw 170 So that the equilibrium state of the loading unit 110 can be adjusted by rotating the screw 170 attached to the load cell 180.

Meanwhile, the load applied to the load cell 180 is converted to a voltage of 0 to 5 V through the load cell amplifier.

As shown in FIG. 3, the signal acquisition and storage device 150 is manufactured based on an open source microcontroller (Mega R3, Arduino, Italy). An RTC module (DS1307 Module, Adafruit, USA) (SD Card Module, Sparkfun, USA) was connected.

Here, the load cell unit 180 may be constituted by an electric resistance type load cell for measuring a load by measuring a resistance value of a cell deformed according to a load.

As a preferred example, a load weight of 1,100 g is placed on each load cell 180 attached to the apparatus to calibrate the load cell 180, and the sum of the weights measured on the individual load cell 180 is used as the total measured weight And the value was recorded.

The load cell unit 180 can measure the change in the moisture content of the litter and soil layer samples by measuring the weight change of the litter and the soil layer sample stored in the loading unit 110.

In addition, the water content output unit 160 can measure a change in moisture contained in the soil layer sample based on a change in the weight value of the soil layer sample measured over time in the load cell unit 180.

Figure 4 shows a micro board signal connection terminal for device signal acquisition and transmission.

In order to minimize the error of the signal storage device 150 of the present invention due to sensitivity and drift of the load cell 180 in the field, signal correction is performed as shown in the following figure and a 2-point normalization method is performed so as to match the initial calibration curve value Respectively. This method is characterized by restoring the electrical signal output from the load cell 180 to the initial sensitivity and residual.

The two-point normalization method calculates a predicted load cell voltage signal corresponding to two weights of different weights known in the first step using an existing calibration formula having a linear relationship with the weight and the voltage signal of the load cell 180 (Y _1n , Y _2n ). The two weights are placed on the monitoring system and the output signal value of the load cell 180 is obtained (Y ₁₀ , Y ₂₀ ). The sensitivity correction coefficient (Y _2n -Y _1n ) / (Y _2o -Y _1o ) of the load cell 180 is calculated from the values Y _1n , Y _2n , Y ₁₀ and Y ₂₀ obtained above, In the change value The signal value of the final load cell 180 is normalized by removing the signal offset using the difference of Y _2n .

 The four load cells 180 installed on the respective surfaces of the loading unit 110 are normalized in the same manner and the values are inserted into the original calibration equation to predict the weight of the sample and the sample weight values predicted from the four load cells 180 Is taken as the representative value on average. Since the two-point normalization method performs an iterative process, it can be programmed. What can be obtained through this is that it is possible to easily normalize and calibrate each load cell in the field so that the signal correction can be simplified. Since the influence on the load can be canceled, the representativeity of the measurement data can be enhanced.

Figure 5 shows a flow chart of a declining moisture content fire alarm algorithm according to an embodiment of the present invention.

The water content (MC) in the soil layer refers to the weight ratio of water to the total weight of completely dried leaves, which is calculated by subtracting the total weight of completely dried leaves from the total weight at a certain point in time relative to the total weight of completely dried leaves Weight ratio. This is expressed by Equation (1).

If the measured value of the litter and soil weights varying over time is the minimum value, it is stored separately and replaced with the new minimum value when the new minimum value is measured. The minimum measured value is considered to be the weight of completely dried litter and soil.

The water content of litter and soil is calculated as follows.

( Equation 1 )

MC (%) =

=

As shown in FIG. 6, the LCD window attached to the signal collecting and storing device indicates the weight, moisture content, and fire risk of the litter layer currently loaded on the fallen weighing apparatus. At this time, a Warning message is displayed when the water content of the fallen leaves and soil layer falls below 5%.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. will be.

Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

100: floor structure 110:
111: bottom part 120: wire mesh
130: Wire mesh support structure 140: Measuring structure
150: Signal storage device 160: Output section
170: screw 180: load cell
190: spring

Claims (11)

An apparatus for measuring moisture content of litters and soil,
A loading unit 110 made of a metal material on the floor structure 100 and capable of containing litter and forest soil layers;
Four measurement substructures 140 installed at the respective central portions of the floor structure 100;
A load cell 180 connected to the loading unit 110;
A spring 190 connecting the loading unit 110 and the measuring unit structure 140;
A screw 170 connecting the loading unit 110 and the load cell 180;
A signal storage device 150 connected to the load cell 180 in a wire or wireless manner to receive the electrical signal of the load cell and use it as weight data to calculate and store the amount of water in each time slot;
And an output unit 160 for outputting a moisture content result value derived through the signal storage device,
Wherein the signal storage device corrects the sensitivity and signal drift phenomenon of the load cell through a two-point normalization method using two standard weights and stores the electrical signal output from the load cell 180, Measuring device
The apparatus according to claim 1, wherein the output unit (160) measures the weight and water content of the litter layer and outputs a warning message when the water content of the litter and the soil layer falls below 5%
The apparatus according to claim 2, wherein the output unit (160) uses an LCD substrate.
The apparatus according to claim 1, wherein the loading unit (110) has a width of 500 mm to 1000 mm, a length of 500 mm to 1000 mm, and a height of 150 mm to 200 mm.
The apparatus according to claim 4, wherein the bottom part (111) of the loading part (110) comprises a wire net (120) having a grid between 10 mm and 20 mm.
5. The method according to claim 4, wherein a wire mesh support structure (130) having a width of 30 mm to 32 mm and a thickness of 2.0 mm to 2.5 mm is used for the bottom part (111) Measuring device
The apparatus according to claim 6, wherein the wire net supporting structure (130) is a cross structure.
2. The apparatus according to claim 1, wherein the spring (190) is deformed by a load of the loading part (110) to form an equilibrium state.
2. The apparatus according to claim 1, wherein the equilibrium state of the loading unit (110) is adjusted by rotating the screw (170) attached to the load cell (180)
The soil moisture measuring apparatus according to claim 1, wherein the signal storage device (150) is connected to the load cell (180) and calculates the moisture content (MC) of the soil through the following equation

MC (%) =

=

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