KR20210042706A - Load sensor comprising compansation means - Google Patents

Abstract

The present invention relates to a load sensor, and more particularly, to a load sensor including a correction means. The present invention is a Wheatstone bridge-type load sensor including four strain gauges, and includes a compensation means at a connection point between the strain gauges. The load sensor including the compensation means of the present invention according to the configuration as described above can obtain an accurate load value even under the heat effect of high temperature that occurs during the operation of an aircraft, and even if the load sensor is attached to parts of the aircraft manufactured in a streamlined shape, it is possible to obtain an accurate load value without being affected thereby. Thus, the present invention has the effect of being able to measure the load value with high reliability.

Description

Load sensor comprising compansation means

The present invention relates to a load sensor, and more particularly, to a load sensor comprising a correction means.

In general, the Wheatstone bridge circuit is a type of bridge circuit, and four resistors form a square shape, and are devices that accurately measure electrical resistance by connecting diagonal lines with a resistor, a voltmeter, or a galvanometer. Among them, a load-cell is a kind of transducer to which a strain gauge is applied. It is mainly used for electronic scales. It includes a metal elastic body with two strain gauges in the compression direction and two strain gauges in the tension direction on the outer surface. If the metal elastic body is deformed by an external load while the current for measuring the applied load is flowing through the strain gauge, the electrical resistance value of the strain gauge changes and the current flowing through the strain gauge changes, responding to this change in current. It converts the output voltage to a digital electric signal and displays it as a number representing the external load.

The principle of the load cell can be used to verify the integrity of the structure of the aircraft, and a load sensor including the strain gauge of the load cell described above is attached to some parts of the aircraft structure to measure the load applied to the parts. Since the structural integrity of aircraft parts is verified and managed in real time while the aircraft is in operation, the load sensor measures the load at the time the aircraft is in operation. However, at this time, the ambient temperature of the load sensor is very high, and each strain gauge is attached to a surface formed in a streamlined shape to maximize lift, so the strain value even without a separate load with the conventional Wheatstone bridge and the load sensor using the strain gauge. There was a problem that an error occurred due to measurement.

Accordingly, the need for a load sensor that is not affected by the surrounding environment during the operation of the aircraft has emerged so that the structural integrity of the aircraft can be verified.

The present invention has been conceived to solve the above problems, and an object of the present invention is to provide a load sensor including a compensation means capable of obtaining an accurate load value even under a high temperature heat effect generated during operation of an aircraft. .

In addition, it is intended to provide a load sensor including a compensation means capable of obtaining an accurate load value without being affected even when attached to a part of an aircraft manufactured in a streamlined form.

In the load sensor including the compensating means of the present invention, a first strain gauge and a second strain gauge are connected in series, a third strain gauge and a fourth strain gauge are connected in series, and the first strain gauge and the first strain gauge are connected in series. 4 A first connection point, which is a connection point of the strain gauge, and a second connection point, which is a connection point between the second strain gauge and the third strain gauge, is connected to a power source, and a third connection point that is a connection point between the first strain gauge and the second strain gauge. And a load measuring means is connected to a fourth connection point, which is a connection point between the third strain gauge and the fourth strain gauge, and includes a first compensation means and a second compensation means connected to the third connection point or the fourth connection point. It characterized in that it includes.

In addition, the first compensation means includes a resistance and compensates for a thermal effect on the load sensor.

In addition, the load sensor including the first compensation means is characterized in that it is quenched three or more times in a chamber in which a constant quenching temperature is maintained.

이상 300C

이하인 것을 특징으로 한다.In addition, the quenching temperature is 100C

More than 300C

It is characterized by the following.

In addition, the first compensation means includes a resistance that can be arbitrarily adjusted by a user, and the resistance value is adjusted to satisfy the following equation.

≤0.3[

C

]

≤0.3[

C

]

(From here,

: 제 1 온도에서의 스트레인 변화량(

)

: The amount of strain change at the first temperature (

)

: 상기 제 1 온도보다 높은 제 2 온도에서의 스트레인 변화량(

)

: Strain change amount at a second temperature higher than the first temperature (

)

: 상기 제 2 온도와 상기 제 1 온도의 차이(C

))

: The difference between the second temperature and the first temperature (C

))

In addition, the resistor is characterized in that it is a lever type variable resistor.

In addition, the resistance is in the form of a printed thin film, and the thickness is adjustable.

In addition, the second compensating means includes a resistance and compensates for maintaining an electrical zero point before the load sensor applies a load.

In addition, the second compensating means is characterized in that it includes a resistance that can be arbitrarily adjusted by the user.

In addition, the resistor is characterized in that it is a lever type variable resistor.

In addition, the resistance is in the form of a printed thin film, and the thickness is adjustable.

In addition, the method of calibrating the load sensor using the compensation means of claim 1 includes attaching the first strain gauge, the second strain gauge, the third strain gauge, and the fourth strain gauge to a load measuring part where a load is measured, and Attaching step of connecting and applying; A quenching step of quenching the load measuring part in a chamber in which a constant quenching temperature is maintained; A temperature compensating step of adjusting a resistance value of the first compensating means such that an error of the measured load value of the sensor according to the temperature difference is equal to or less than a predetermined value; And a zero-point compensation step of adjusting the resistance capacity of the second compensating means so as to maintain an electrical zero point when no load is applied to the load sensor.

In addition, the quenching step is characterized in that it is carried out repeatedly three or more times.

이상 300C

이하인 것을 특징으로 한다.In addition, the quenching temperature is 100C

More than 300C

It is characterized by the following.

/C

]이하인 것을 특징으로 한다.In addition, the error of the load measurement value is 0.3[

/C

] It is characterized by the following.

The load sensor including the compensation means of the present invention having the above configuration can obtain an accurate load value even with the high temperature heat effect generated during the operation of the aircraft, and even when attached to the parts of the aircraft manufactured in a streamlined manner, this effect Since it is possible to obtain an accurate load value without receiving it, it has the effect of measuring a load value with high reliability.

1 is a circuit diagram of the load sensor of the present invention.
2 is a conceptual diagram showing an installation embodiment of the strain gauge of the present invention.
3 is a flow chart showing a method of compensating a load sensor using the compensation means of the present invention.

Hereinafter, the technical idea of the present invention will be described in more detail using the accompanying drawings. Prior to this, terms or words used in the specification and claims should not be construed as being limited to their usual or dictionary meanings, and the inventors appropriately explain the concept of terms in order to explain their own invention in the best way. Based on the principle that it can be defined, it should be interpreted as a meaning and concept consistent with the technical idea of the present invention.

Therefore, the embodiments described in the present specification and the configurations shown in the drawings are only one of the most preferred embodiments of the present invention, and do not represent all the technical ideas of the present invention, so that they can be replaced at the time of the present application. It should be understood that there may be various variations.

Hereinafter, the technical idea of the present invention will be described in more detail using the accompanying drawings. The accompanying drawings are only an example illustrated to describe the technical idea of the present invention in more detail, so the technical idea of the present invention is not limited to the form of the accompanying drawings.

Hereinafter, the configuration of the load sensor 1000 including the compensation means 300 of the present invention will be described with reference to FIG. 1.

The load sensor 1000 including the compensating means 300 of the present invention is formed in the form of a Wheatstone bridge, and in more detail, the first strain gauge 110 and the second strain gauge are connected in series, and the third The strain gauge 130 and the fourth strain gauge 140 are connected in series, and the first connection point 210 and the second strain gauge 120, which are connection points between the first strain gauge 110 and the fourth strain gauge 140, are ) And the second connection point 220, which is a connection point between the third strain gauge 130, is connected to a power source, and the third connection point 230 and the third connection point 230, which is a connection point between the first strain gauge 110 and the second strain gauge 120, are connected to the power supply. It is preferable that the load measuring means is connected to the fourth connection point 240 which is the connection point between the 3 strain gauge 130 and the fourth strain gauge 140.

In this case, a compensation means 300 connected to at least one of the third connection point 230 or the fourth connection point 240 may be included. By including the compensation means 300, the present invention is not affected by the surrounding environment so that the load sensor 1000 is not affected by the surrounding environment even in a special situation (high temperature, structurally no load is applied, but the strain acts on the strain gauge). It has the effect of compensating. It is preferable that a plurality of compensation means 300 are included depending on the type of influence to be compensated.

Hereinafter, each embodiment of the compensation means 300 will be described.

In the first embodiment of the compensation means 300, the compensation means 300 may be a first compensation means. The first compensating means may compensate for the thermal effect on the load sensor 1000, and preferably includes a variable resistance whose resistance value can be changed arbitrarily by the user. The variable resistor may be in a form in which the resistance value is changed in the form of a lever, in the form of a printed thin film, and may be in a form in which the thickness can be adjusted with a metal eraser or the like. In this way, the load sensor 1000 including the first compensation means can obtain only a desired load value even if a high temperature acts on the load sensor 1000 in verifying the integrity of the aircraft structure.

In order to obtain the resistance value of the first compensating means, the load sensor 1000 including the first compensating means may be quenched three or more times in a chamber in which a constant quenching temperature is maintained. When the load sensor 1000 is applied to the load measuring part 2000 in which the load of the aircraft is to be measured, the thermal effect applied to the load sensor 1000 and the load measuring part 2000 has a constant value, which is not expected. It is possible to train the load sensor 1000 and the load measurement component 2000 in advance at the temperature of the expected value as close as possible.

이상 300C

이하인 것이 바람직하다. 이는 통상적으로 항공기를 운행할 때 항공기 부품에 가해지는 온도가 100C

이상 300C

이하의 범위에 포함되기 때문이다. The reason for the training is to stabilize the strain value of the load sensor 1000 according to temperature and linearize the compensation value to be easily derived. The quenching temperature at this time is 100C

More than 300C

It is preferable that it is the following. This is because the temperature applied to aircraft parts is typically 100C when operating an aircraft.

More than 300C

It is because it is included in the following range.

The first compensation means is preferably attached to the load sensor 1000 after the quenching of the load sensor 1000 and the load measuring component 2000 is completed. It is preferable that the resistance value of the first compensating means satisfies Equation 1.

[Equation 1]

≤0.3[

C

]

≤0.3[

C

]

: 제 1 온도보다 높은 제 2 온도에서의 스트레인 변화량(

)

: 제 1 온도에서의 스트레인 변화량(

)

: 제 2 온도와 제 2 온도의 차이(C

)) 이 때, 제 1 온도는 15C

내지 25C

의 상온인 것이 바람직하며, 제 2 온도는 상술한 담금질 온도인 100C

내지 300C

인 것이 바람직하다.(From here,

: The amount of strain change at the second temperature higher than the first temperature (

)

: The amount of strain change at the first temperature (

)

: The difference between the second temperature and the second temperature (C

)) At this time, the first temperature is 15C

To 25C

It is preferable that it is room temperature, and the second temperature is 100 C, which is the above-described quenching temperature.

To 300C

It is preferable to be.

값은 담금질이 완료된 이후, 스트레인 값이 안정된 상태일 때 측정하는 것이 바람직하다. 수식 1의 각 변수는 실시간으로 측정되어 수식 1의 좌변의 값이 실시간으로 도출되는 것이 바람직하고, 사용자는 각 변수를 실시간으로 관측하며 제 1 보상수단의 저항값을 변화시키는 것이 바람직하다.Also,

The value is preferably measured when the strain value is in a stable state after the quenching is completed. It is preferable that each variable of Equation 1 is measured in real time so that the value of the left side of Equation 1 is derived in real time, and it is preferable that the user observes each variable in real time and changes the resistance value of the first compensation means.

Hereinafter, a second embodiment of the compensation means 300 will be described with reference to FIG. 2.

In the second embodiment of the compensation means 300, the compensation means 300 may be a second compensation means. As shown in FIG. 2, when the surface of the load measurement component 2000 to which the first to fourth strain gauges 110 to 140 are attached is curved, micro strain may occur, and a load value according to this Error may occur.

The second compensating means is for compensating for a plurality of micro strain errors including this. The second compensating means may compensate so that the load sensor 1000 electrically maintains the zero point before applying the load, and preferably includes a variable resistance whose resistance value can be changed arbitrarily by the user. The variable resistor may be in a form in which the resistance value is changed in the form of a lever, in the form of a printed thin film, and may be in a form in which the thickness can be adjusted with a metal eraser or the like. In this way, the load sensor 1000 including the first compensation means can obtain only a desired load value even if a high temperature acts on the load sensor 1000 in verifying the integrity of the aircraft structure.

Hereinafter, a method of calibrating the load sensor 1000 including the compensation means 300 will be described with reference to FIG. 3.

The method of calibrating the load sensor 1000 using the compensation means 300 is an attaching step of attaching the first, second, third, and fourth strain gauges to the load measuring part 2000 on which the load is measured, and connecting and applying power. It may include (S1). In addition, the method of calibrating the load sensor 1000 using the compensation means 300 may include a quenching step (S2) of quenching the load measuring component 2000 in a chamber maintaining a constant quenching temperature. The quenching step (S2) is for linearizing by stabilizing the strain value of the load sensor 1000 generated by temperature. The quenching step (S3) is preferably repeated three or more times, and the quenching temperature is preferably from 100 degrees to 300 degrees.

In addition, the method of calibrating the load sensor 1000 using the compensation means 300 is a temperature compensation step of adjusting the resistance value of the first compensation means so that the error of the load measurement value of the sensor according to the temperature difference becomes less than a certain value ( S3) may be included. The temperature compensation step (S3) is preferably performed after the quenching step (S2) is completed, and is a step of designating the resistance value of the first compensation means to be attached to the load sensor 1000 having a stable strain value at the quenching temperature. It is preferable that the resistance value of the first compensating means is adjusted so that the resistance value of the first compensating means satisfies Equation 1 above. In addition, the temperature compensation step S3 may also include a process of attaching the first compensation means to the load sensor 1000.

In addition, the method of calibrating the load sensor 1000 using the compensation means 300 is zero compensation for adjusting the resistance capacity of the second compensation means to maintain the electrical zero point when no load is applied to the load sensor 1000. It may include a step (S4). 4 shows that the zero point compensation step (S4) is performed after the temperature compensation step (S3), but this is only an example, the zero point compensation step (S4) and the temperature compensation step (S3) are in a parallel relationship with each other, The order of implementation may vary.

As described above, in the present invention, specific matters such as specific elements, etc., and limited embodiments have been described, but this is provided only to help a more general understanding of the present invention, and the present invention is limited to the above one embodiment. It is not, and a person of ordinary skill in the field to which the present invention belongs can make various modifications and variations from this description.

Therefore, the spirit of the present invention is limited to the described embodiments and should not be determined, and all things that have equivalent or equivalent modifications to the claims as well as the claims to be described later belong to the scope of the spirit of the present invention. .

1000: load sensor
110: first strain gauge
120: second strain gauge
130: third strain gauge
140: fourth strain gauge
210: first connection point
220: second connection point
230: third connection point
240: fourth connection point
300: compensation means
2000: load measurement part

Claims (15)

The first strain gauge and the second strain gauge are connected in series, the third strain gauge and the fourth strain gauge are connected in series,
A first connection point that is a connection point between the first strain gauge and the fourth strain gauge, and a second connection point that is a connection point between the second strain gauge and the third strain gauge are connected to a power source,
In a load sensor in which a load measuring means is connected to a third connection point, which is a connection point between the first strain gauge and the second strain gauge, and a fourth connection point, which is a connection point between the third strain gauge and the fourth strain gauge,
A load sensor comprising a compensating means, characterized in that it comprises a first compensating means and a second compensating means connected to the third connection point or the fourth connection point.
The method of claim 1,
The first compensating means comprises a resistance and a load sensor comprising a compensating means, characterized in that compensating for a thermal effect acting on the load sensor.
The method of claim 2,
The load sensor including the first compensating means is a load sensor comprising a compensating means, characterized in that it is quenched three or more times in a chamber in which a constant quenching temperature is maintained.
The method of claim 3,
The quenching temperature is 100C

More than 300C

Load sensor comprising a compensation means, characterized in that the following.
The method of claim 3,
The first compensating means includes a resistance that can be arbitrarily adjusted by a user, and the resistance value is adjusted to satisfy the following equation.

≤0.3[

C

]
(From here,

: The amount of strain change at the first temperature (

)

: Strain change amount at a second temperature higher than the first temperature (

)

: The difference between the second temperature and the first temperature (C

))


The method of claim 5,
The load sensor comprising a compensating means, characterized in that the resistance is a variable resistance of a lever type.
The method of claim 5,
The resistance is in the form of a printed thin film, the load sensor comprising a compensation means, characterized in that the thickness is adjustable.
The method of claim 1,
The second compensating means comprises a resistance, and the load sensor comprising a compensating means for compensating to maintain an electrical zero point before the load sensor applies a load.
The method of claim 8,
The second compensating means is a load sensor comprising a compensating means, characterized in that it comprises a resistance that can be arbitrarily adjusted by the user.
The method of claim 9,
The resistance is a load sensor comprising a compensation means, characterized in that the variable resistance of the lever type.
The method of claim 9,
The resistance is in the form of a printed thin film, the load sensor comprising a compensation means, characterized in that the thickness is adjustable.
The method of compensating the load sensor using the compensation means of claim 1
An attaching step of attaching the first strain gauge, the second strain gauge, the third strain gauge, and the fourth strain gauge to a load measuring component for which a load is measured, and connecting and applying power;
A quenching step of quenching the load measuring part in a chamber in which a constant quenching temperature is maintained;
A temperature compensating step of adjusting the resistance value of the first compensating means so that the error of the load measurement value of the sensor according to the temperature difference is equal to or less than a predetermined value;
A zero point compensation step of adjusting the resistance capacity of the second compensation means to maintain an electrical zero point when no load is applied to the load sensor;
Method for compensating a load sensor using a compensation means comprising a.
The method of claim 12,
The method of compensating a load sensor using a compensation means, characterized in that the quenching step is repeated three or more times.
The method of claim 12,
The quenching temperature is 100C

More than 300C

Method for compensating a load sensor using a compensation means, characterized in that the following.
The method of claim 12,
The error of the load measurement value is 0.3[

/C

] Method for compensating a load sensor using a compensation means, characterized in that the following.

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