KR100827713B1 - Method for calculating tension applied to cable tension sensor and deriving method thereof - Google Patents

Abstract

A method for calculating tension in a cable tension sensor and a deriving method thereof are provided to detect actual tension change applied to a cable by converting electrical energy from the tension sensor to a tension at a reference ambient temperature. A method for calculating tension in a cable tension sensor includes the steps of: changing magnetic field and tension of a cable and measuring output voltage of the tension sensor(S11); checking intensity of the magnetic field showing linearity(S13); measuring output voltage in the strength of the magnetic field after changing temperature and tension in the cable(S15); setting a reference temperature(S17); calculating the difference between output voltage under the reference temperature and output voltage at a different temperature(S19); obtaining temperature correction formula according to temperature change using the voltage difference(S21); obtaining an output voltage formula at the reference temperature according to tension change using the temperature correction formula(S23); and converting the output voltage formula to a tension calculation formula(S25).

Description

Method for calculating tension applied to cable tension sensor and deriving method

1 is a cross-sectional structural view of a cable that can be applied to the present invention,

2 is a graph showing magnetic flux density characteristics of a magnetic body according to a change in tension and magnetic field applied to the magnetic body;

3 is a conceptual view showing a schematic structure of a cable tension sensor that can be applied to the present invention,

4 is a cable tension test circuit diagram configured to derive a tension calculation algorithm applied to the cable tension sensor according to the present invention;

5 and 6 are photographs showing the appearance of the cable tension sensor that can be applied to the present invention,

7 is a photograph showing the appearance of a tensile tester for applying artificial tension to the cable,

8 to 10 is a graph showing the output voltage characteristics of the tension sensor according to the change in frequency and magnetic field applied to the tension sensor in the cable tension test circuit diagram shown in FIG.

11 and 12 are graphs showing the output voltage characteristics of the tension sensor according to the temperature change of the cable in the cable tension test circuit diagram shown in FIG.

FIG. 13 is a graph illustrating output voltage characteristic graphs shown in FIG. 12 converted into deviation characteristics of output voltages at different temperatures with respect to output voltages at a predetermined reference temperature. FIG.

14 is a graph showing the characteristics of the output voltage calculated through the temperature correction equation based on the voltage deviation characteristic graph of FIG.

15 is an output voltage characteristic graph shown through FIG. 14, a tension characteristic graph converted to show a change in tension according to an output voltage of a tension sensor;

16 is a flowchart illustrating a derivation method of a tension calculation algorithm applied to a cable tension sensor according to an exemplary embodiment of the present invention.

*** Explanation of symbols for the main parts of the drawing ***

10: Cable 11: Core

13: strand 30: primary coil

40: secondary coil 100: tension sensor

200: power supply device 300: shunt

400: current meter 500: voltage meter

The present invention relates to a tension calculation method and a method for deriving the tension sensor applied to the cable tension sensor, in particular, when the cable is placed in the magnetic field and the relationship between the length and the magnetic field is formed, the electrical input from the tension sensor implemented through Tension calculation method applied to cable tension sensor and its derivation method which can evaluate the effect of the tension applied to the cable substantially without the influence of temperature by converting the energy into the corresponding tension at the arbitrarily determined reference temperature. will be.

Since large bridges, such as cable-stayed bridges and suspension bridges, are constructed in poor environments, there is a high possibility of damage to the structure due to excessive displacement of the bridges due to wind loads or corrosion of the bridges by seawater. Cables are commonly used. In particular, cables have little flexural rigidity and thus are not affected by compression, but are affected by tension. Here, known techniques for measuring tension include a load gauge measurement method and an accelerometer measurement method. However, the load gauge is the difficulty of installation, and the accelerometer measures the frequency of steel wire or steel rod and converts it to tension, but the measurement is simple, but the tension calculation can vary according to the constraints, length, cross-sectional area of cable, etc. Difficult to follow, and furthermore, there was a problem of lack of reliability and reproducibility. Therefore, research on tension sensors that can be used as a standard by developing a series of technologies such as a tension measuring device and a tension sensor, which are more reproducible and reliable than the above-described method, is being actively conducted. The length and the magnetic field are correlated, and thus the magnetic field method for measuring the tension applied to the cable is emerging. On the other hand, the temperature can not be overlooked as an environmental factor affecting the length of the cable in addition to the tension as described above, there was a problem that this temperature affects in calculating the tension on the cable. In addition, even though the tension applied to the cable is substantially the same, the output value from the tension sensor is different due to the parameter of temperature, and thus the calculated tension may be different. Therefore, the actual tension without the influence of temperature is calculated. There is a problem that additional work that needs to be done, and thus continuous tension calculation is impossible. Therefore, it is necessary to exclude the cable length changed by the influence of temperature in calculating the tension will be an essential problem in the tension calculation method according to the magnetic field method.

The present invention has been made to solve the above problems, the tension calculation method applied to the cable tension sensor so that the electrical energy input from the tension sensor according to the magnetic field method is converted into a tension at a corresponding arbitrarily predetermined reference temperature It is an object of the present invention to provide a method for deriving the above-mentioned tension calculation method with high reproducibility and reliability through the evaluation of the temperature influence and the magnetic flux effect of the cable for the and the tension sensor.

In order to achieve the above object, a tension calculation method applied to a cable tension sensor according to an embodiment of the present invention applies an artificially constant magnetic field to a cable, and based on the applied magnetic field, applies a tension applied to the cable to a corresponding voltage. In the tension calculation method applied to the cable tension sensor to output,

In the tension calculation method applied to the cable tension sensor applying a magnetic field artificially constant to the cable, and outputs the tension applied to the cable at a corresponding voltage based on the applied magnetic field,

와; 상기 온도보정식을 통해 기준온도일 때의 상기 케이블 장력센서의 출력전압을 계산하는 출력전압계산식

와; 상기 온도보정식과 상기 출력전압계산식으로부터 유도되는 수학식으로써, 상기 케이블 장력센서로부터 출력되는 전압과 상기 케이블 온도를 토대로 상기 기준온도일 때의 케이블에 인가되는 장력을 산출하는 장력산출식

중에서 상기 장력산출식에 의해 장력이 얻어지되,A temperature correction equation for calculating a deviation between the voltage output from the cable tension sensor and the output voltage of the cable tension sensor when the cable is a preset reference temperature

Wow; Output voltage calculation formula for calculating the output voltage of the cable tension sensor at the reference temperature through the temperature correction equation

Wow; A tension calculation equation that calculates the tension applied to the cable at the reference temperature based on the voltage output from the cable tension sensor and the cable temperature as an equation derived from the temperature correction equation and the output voltage calculation equation.

Tension is obtained by the above tension calculation formula,

V _O (t) is the output voltage of the cable tension sensor, T is the measured temperature of the cable when the V _O (t) is output, and T _C2 and T _C1 and T _C0 are A constant value derived from the material and thickness of the cable, the strength of the magnetic field applied to the cable tension sensor, and the reference temperature, and V _C is output from the cable tension sensor in a state where no magnetic field is applied to the cable. An initial voltage, and the F _C2 and the F _C1 and the F _C0 is a constant value derived from the T _C2 and T _C1 and T _C0 provides a tension calculation method applied to the cable tension sensor.

In addition, the derivation method of the tension calculation method applied to the cable tension sensor according to another embodiment of the present invention based on the magnetic field applied to the cable tension applied to the cable tension sensor for outputting the tension applied to the cable with a corresponding voltage A method of deriving a calculation method, comprising: (a) applying a change in magnetic field and tension to the cable and measuring the output voltage of the cable tension sensor obtained by the change in the magnetic field and tension; (B) extracting the strength of the magnetic field to have linearity in the characteristics of the output voltage measured in step (a); (C) measuring the output voltage of the cable tension sensor obtained by applying a change in temperature and tension to the cable artificially at the strength of the magnetic field extracted in step (b); (D) setting a reference temperature among the changed temperatures, and calculating a voltage deviation between the output voltage at the reference temperature and the output voltage at another temperature among the output voltages measured in the step (c); (E) deriving a temperature correction equation based on temperature change based on the voltage deviation calculated in step (d); (F) deriving an output voltage calculation formula for calculating an output voltage of the cable based on a change in tension at the reference temperature based on the temperature correction formula derived in step (e); And (g) converting the output voltage calculation formula derived in the step (f) into a tension calculation formula for calculating the tension. .

이되, 상기 T는 상기 케이블에 인가되는 온도이고, 상기 T_C2와 상기 T_C1과 상기 T_C0는 상기 케이블의 재료와 상기 케이블의 두께와 상기 케이블 장력센서로 인가되는 자기장의 세기와 상기 (d) 단계에서 설정된 기준온도로부터 유도되는 상수값이며,In the above-described configuration, the temperature correction formula derived in step (e)

Wherein T is the temperature applied to the cable, T _C2 and T _C1 and T _C0 is the material of the cable and the thickness of the cable and the strength of the magnetic field applied to the cable tension sensor and (d) Constant value derived from the reference temperature set in step,

이되, 상기 V_O(t)는 상기 케이블 장력센서로부터 출력되는 전압이며, 상기 V_C는 상기 케이블에 자기장이 인가되지 않은 상태에서 상기 케이블 장력센서에서 출력되는 초기전압이며,The output voltage calculation formula derived in step (f)

Here, the V _O (t) is the voltage output from the cable tension sensor, the V _C is the initial voltage output from the cable tension sensor in the state that the magnetic field is not applied to the cable,

이되, 상기 F_C2와 상기 F_C1과 상기 F_C0는 상기 T_C2와 상기 T_C1과 상기 T_C0로부터 유도되는 상수값인 것이 바람직하다.The tension calculation formula derived in step (g)

Preferably, the F _C2 , the F _C1, and the F _C0 are constant values derived from the T _C2 , the T _C1, and the T _C0 .

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

First, the accompanying drawings will be described to explain the principle of the tension calculation method and its derivation method applied to the cable tension sensor according to an embodiment of the present invention.

1 is a cross-sectional structural view of a cable that can be applied to the present invention.

3.24mm 와이어 19가닥과

1.4mm 와이어 6가닥으로 구성되어 있으며, 모두 6개의 스트랜드(13)가 있고 코어(11)는

2.0mm 와이어가 7가닥으로 구성된 코어가 7개가 있다.Referring to Figure 1, the internal tension material used in the bridge collectively referred to as tendon (tendon), the external tension material collectively referred to as a cable, where the cable 10 is a tensioning unit, the configuration of the bundle of wires, steel rods, Consists of a strand, the structure is divided into a core (11) formed of a wire bundle and several strands (13) surrounding it. Here, the cable 10 has a diameter of 50 mm, in particular the strand 13

3.24mm wire with 19 strands

It consists of 6 strands of 1.4 mm wire, all 6 strands 13 and the core 11

There are seven cores consisting of seven strands of 2.0mm wire.

2 is a graph showing magnetic flux density characteristics of a magnetic body according to changes in tension and magnetic field applied to the magnetic body.

이라 하면 그 변형률(strain)

는 다음 수학식 1과 같다.When the ferromagnetic cable 10 is placed in a magnetic field, its length is changed, which is called magnetostriction.

This is the strain

Is equal to the following Equation 1.

을 이 케이블(10)에 가하면 일정한 자기장 하에서 자화가 'B'로 증가한다. 한편, 인장력 없이 자계를 'H₁->H₂->0'으로 하게 되면, 잔류 자속밀도는 B_R1이 되며, 인장력

을 가하면 이것이 B_R2로 증가한다. 그러나, 자기소거된 즉, 자기장이 '0'인 케이블(10) 상태에서는 인장력이 인가되어도 도 2에 도시한 바와 같이 실선과 점선이 원점에서 교차되므로 어떤 자화의 변화도 일으키지 않게 된다. 이상과 같이 외부 장력에 따라 자화곡선이 달라지는데, 이것은 투자율이 장력에 따라 변하기 때문이다. 즉, 케이블(10)에 걸린 장력에 따라 자속밀도의 변화가 발생되는 것이다.Therefore, when the cable 10 is magnetized, the length thereof is further increased. When artificial tension is applied to the cable 10 magnetized by this correlation, the degree of extension and magnetization is increased. That is, as shown in FIG. 2, when there is no tensile force in the BH curve (magnetic flux density-magnetic field curve), when the magnetic field H ₁ is applied, the magnetization becomes 'A' and the tensile force is obtained.

Is applied to this cable 10, the magnetization increases to 'B' under a constant magnetic field. On the other hand, if the magnetic field is 'H _1- > H _2- >0' without the tensile force, the residual magnetic flux density is B _R1 , the tensile force

Adding it increases to B _R2 . However, in the cable 10 state in which the magnetic field is self-erased, that is, the magnetic field is '0', even if a tensile force is applied, as shown in FIG. As mentioned above, the magnetization curve varies according to the external tension, because the permeability changes according to the tension. That is, a change in magnetic flux density occurs according to the tension applied to the cable 10.

Figure 3 is a conceptual view showing a schematic structure of a cable tension sensor that can be applied to the present invention, is a conceptual diagram of a tension sensor made using the above principle. 3, 'N ₁ ' is the number of turns of the primary coil 30, 'N ₂ ' is the number of turns of the secondary coil 40, 'S ₁ ' is inside the primary coil 30 Cross-sectional area (m ² ), 'S ₂ ' is the internal cross-sectional area of the secondary coil 40, 'S _C ' is the cross-sectional area of the core 11, 'd ₁ ' is the diameter of the primary coil 30, 'd ₂ ' Is the diameter of the secondary coil 40, 'd _C ' is the diameter of the core, 'l' is the length of the primary coil 30.

를 가하였을 때, 2차 코일(40)에 유기되는 전압은 패러데이법칙에 의해 다음 수학식 2와 같다.Current in primary coil 30

When is applied, the voltage induced in the secondary coil 40 is expressed by the following equation 2 by Faraday's law.

은 1차 코일(30)에서 발생된 자속이 2차 코일(40)에 전달된 자속인 것으로써, 이것은 1차 코일(30)에서 발생된 자속(

)에서 1차 코일(30) 내부와 2차 코일(40) 사이의 공간(Sg=S1-S2)에 흐르는 자속(

)을 제하면 2차 코일(40)에 전달된 자속이 된다.here,

Is the magnetic flux generated in the primary coil 30 is the magnetic flux transmitted to the secondary coil 40, which is the magnetic flux generated in the primary coil 30 (

Magnetic flux flowing in the space (Sg = S1-S2) between the primary coil 30 and the secondary coil 40 at

) Is the magnetic flux transmitted to the secondary coil 40.

 Therefore, the magnetic flux transmitted to the secondary coil 40 is as shown in Equation 3 below.

이고, 2차 코일(40)에 유기된 전압은 수학식 3을 수학식 2에 대입하면 다음 수학식 4과 같은바, 투자율

을 알 수 있다면 2차 코일(40)에 유기된 전압을 구할 수 있게 된다.In this equation 3,

, And the voltage induced in the secondary coil 40 is equal to the following Equation 4 by substituting Equation 3 into Equation 2.

If it can be seen that the voltage induced in the secondary coil 40 can be obtained.

는 진공투자율로서,

와 같다.here,

Is the vacuum permeability,

Same as

However, the permeability has a characteristic that varies depending on the tension (σ), temperature (T), magnetic field (H) as described above, so the output voltage also changes depending on the tension, temperature, magnetic field, Equation 4 is Same as 5.

At this time, the induced voltage when there is no cable in the secondary coil 40 is as follows.

에 대해 정리하면 다음 수학식 8과 같게 된다. 여기서,

로서 비투자율이라 한다.In other words, dividing Equation 6 from Equation 5 results in Equation 7 below.

In summary, Equation 8 is obtained. here,

It is called as a specific permeability.

That is, what can be seen through Equation 8 is that the relative permeability can be obtained by obtaining the voltage induced in the secondary coil 40 when there is a cable in and without a constant magnetic field. This indicates that if the correlation between the tension applied to the cable 10 and the voltage induced in the secondary coil 40 is established, the tension can be derived from the voltage induced in the secondary coil 40. have.

Next, on the basis of the principle described above will be described in detail the tension calculation method and its derivation method applied to the cable tension sensor according to an embodiment of the present invention.

4 is a cable tension test circuit diagram configured to derive a tension calculation algorithm applied to the cable tension sensor according to the present invention.

As shown in FIG. 4, the configuration of the circuit diagram for the tension test of the cable 10 includes a tension sensor 100 mounted to the cable 10; A power supply device 200 for applying a magnetic field to the primary coil 30 of the tension sensor 100; A current meter 400 for measuring an input current applied to the primary coil 30; A shunt 300 for measuring current more precisely than the current meter; And a voltage meter 500 for measuring an output voltage output through the secondary coil 40 of the tension sensor 100. Here, as the power supply 200, a power supply for outputting sinusoidal wave power of 0.3 App (0.3 A peak to peak) will be used.

5 and 6 is a photograph showing the appearance of the cable tension sensor that can be applied to the present invention, the tension sensor 100 that is a component of the above circuit diagram as a resource 'N ₁ = 1203', ' N ₂ = 460 ',' l = 0.2408m ',' d ₁ = 0.0735m ', and' d ₂ = 0.0617m '. In addition, Figure 7 is a photograph showing the appearance of a tensile tester for applying a tensile force to the cable, both ends of the cable 10 is equipped with a tension sensor 100 in this tensile tester will be connected. Here, the length of the cable 10 will be 1350 mm. In addition, the maximum tensile force of the above tensile tester will be 300 tons, the pressurization will be automatically increased to the set tensile force and stopped for a specified time and then automatically applied to the next tensile force.

On the other hand, in order to measure the tension applied to the cable 10, the output of the tension sensor 100 should be large and changeable according to the tension and must be reproducible. This is a factor that determines the performance of the tension sensor. Therefore, as shown in FIG. 2, an appropriate magnetic field is applied to the cable 10 mounted on the tension sensor 100 so that the output characteristics are good. Thus, a current flows through the primary coil 30 to the cable inside the tension sensor 100. In the state of applying a magnetic field, the tension was changed by the tension tester and the output voltage of the tension sensor 100 was measured. At this time, the frequency was also changed and evaluated at the same time.

8 to 10 are graphs showing the output voltage characteristics of the tension sensor according to the change in frequency and magnetic field applied to the tension sensor in the cable tension test circuit diagram shown in FIG. The frequency is changed to 140, 100, 50, and 10 Hz with 0 "," 23.9 ", and" 32.24 "K (AT / m) applied, respectively, and the result of the tension change and the output voltage is measured.

As shown in FIG. 8, when the magnetic field is not applied to the cable 10, the distribution itself is poor. When the magnetic field is 23.9K as shown in FIG. 9, the output voltage characteristic is improved as compared with when the magnetic field is not applied. However, the linearity is somewhat lowered, and when the magnetic field is applied to 32.24 k (AT / m) a little higher as shown in FIG. 10, the linearity is surely improved, but the reproducibility is still insufficient. Therefore, it can be seen that as the strength of the magnetic field applied to the cable 10 increases, linearity and reproducibility are improved. In addition, the frequency was tested at the same time as the magnetic field, it was confirmed that the fluctuations in the magnitude of the output voltage, but does not significantly affect the linearity or reproducibility.

11 is a graph showing the output voltage characteristics of the tension sensor according to the temperature change of the cable in the cable tension test circuit diagram shown in Figure 4, in order to confirm this result, as well as artificially applying temperature to the cable 10, the temperature sensor To be installed on the cable 10 located inside the tension sensor 100. That is, as shown in FIG. 11, when the temperature is increased, the permeability of the cable 10 decreases, so that the voltage output from the tension sensor 100 falls. Therefore, when the magnetic field is constant as H _C in Equation 8, the change in permeability according to temperature is shown in Equation 9 below.

는 T=20℃에서 자기장이 H _C 로 일정할 때의 비투자율이다. 즉, 수학식 9를 통해 비투자율은 온도에 비례되는 것을 알 수 있다.Where α is a constant,

Is the specific permeability when the magnetic field is constant at H _C at T = 20 ° C. That is, it can be seen from Equation 9 that the specific permeability is proportional to the temperature.

와, 수학식 9를 수학식 5에 대입하여 정리하면 다음 수학식 10과 같다.together,

Then, by substituting Equation 9 into Equation 5, Equation 10 is obtained.

와 같은바, 여기서 온도가 20℃일때의 출력전압식으로 정리하면 다음 수학식 11과 같다.Where K ₁ is the temperature compensation value

As shown in the following, where the output voltage when the temperature is 20 ℃ can be summarized as in the following equation (11).

That is, what can be seen through Equation 11 is a constant magnetic field, in particular a magnetic field that implements the linearity and reproducibility is applied to the tension sensor 10, the cable temperature inside the tension sensor 10 and the above temperature correction value It can be found that the output voltage at 20 ° C, that is, at the reference temperature, can be obtained. In other words, it is possible to confirm the output voltage according to the variation of the length of the cable 10 from which the influence of the temperature is excluded, and ultimately to calculate the tension at the reference temperature corresponding to the output voltage.

Next, the tension calculation method of the present invention and its derivation method will be described in more detail based on the above-described theory. Prior to this, as a tension test condition, the magnetic field applied to the cable is '38 .2K (AT / m) ', the AC frequency and the current applied to the primary coil 30 are '50 Hz and 0.3App', and the reference temperature is' 20 ° C. ' In addition, artificial tension is applied to the cable 10 through the tensile tester as shown in FIG.

12 is a graph showing the output voltage characteristics of the tension sensor according to the temperature change of the cable in the cable tension test circuit diagram shown in Figure 4, Table 1 below is a result of the alignment of the results of FIG. Here, the unit of the result of Table 1 will be 'V'.

Tension (ton) 12 ℃ 20 ℃ 28 ℃ 36 ℃ 43 ℃ 49 ℃ 55 ℃ 58 ℃ 0 0.7556 0.7451 0.7400 0.7344 0.7287 0.7223 0.7177 0.7128 10 0.7672 0.7578 0.7530 0.7477 0.7417 0.7360 0.7301 0.7251 20 0.7753 0.7665 0.7619 0.7565 0.7512 0.7454 0.7396 0.7349 30 0.7839 0.7758 0.7712 0.7660 0.7603 0.7550 0.7495 0.7447 40 0.7922 0.7843 0.7801 0.7749 0.7695 0.7643 0.7588 0.7542 50 0.7996 0.7927 0.7885 0.7837 0.7786 0.7733 0.7676 0.7630 60 0.8067 0.8013 0.7967 0.7921 0.7871 0.7821 0.7764 0.7721 70 0.8147 0.8096 0.8056 0.8010 0.7957 0.7904 0.7857 0.7807 80 0.8231 0.8186 0.8143 0.8095 0.8051 0.7998 0.7944 0.7901 90 0.8362 0.8279 0.8233 0.8186 0.8131 0.8087 0.8040 0.7996

) 즉, 현재온도에서의 출력전압과 기준온도에서의 출력전압간의 전압편차식은 다음 수학식 12와 같다.The temperature correction equation derived from these results

That is, the voltage deviation equation between the output voltage at the current temperature and the output voltage at the reference temperature is as shown in Equation 12 below.

이고,

이며, V_C는 케이블(10)에 자기장이 인가되지 않은 상태에서 장력센서(100)에 출력되는 '장력센서초기값'이며, 표 1에 도시된 결과치를 토대로 상기한 온도보정식을 T(온도)에 대한 함수로 환산하면 다음 수학식 13이 된다.here,

ego,

V _C is the 'tension sensor initial value' output to the tension sensor 100 in the state in which the magnetic field is not applied to the cable 10, and based on the results shown in Table 1, the temperature correction equation is T (temperature). In terms of the function for), the following equation (13) is obtained.

Here, '-0.0133' is a constant value that varies according to the set reference temperature. FIG. 13 is a graph showing the output voltage characteristic graph shown through FIG. 12 as a deviation characteristic of the output voltage at another temperature with respect to the output voltage at an arbitrarily set reference temperature, and curve fitting (curve) (13) is obtained by fitting. That is, it can be seen from FIG. 13 that the deviation voltage shows a linear characteristic with respect to temperature. In addition, Equation 13 is a formula obtained by curve fitting the graph of FIG. 13 obtained by the above-described tension test conditions, and generalized to the following Equation 14.

Here, T _C2 , T _C1 , and T _{C0 on the} right side are constant values derived from the cable material, the cable thickness, and the strength of the magnetic field applied to the tension sensor 100.

Meanwhile, the output voltage at the reference temperature derived through Equations 12 and 13 is the same as Equation 15, and FIG. 14 is a graph showing the characteristics of the output voltage at the reference temperature derived through Equation 15. . In other words, applying Equation 15 to Table 1, it can be seen that the same result can be obtained within the measured value and the error range of 3%.

Thus obtained equation (15) is converted to a function for the tension as shown in the following equation 16, Figure 15 is a graph showing the tension characteristics applied to the cable 10 at the reference temperature derived through the equation (16). That is, the result obtained by curve fitting in FIG. 15 is Equation 16.

Here, the unit of F (t) is ton, t represents the time, '71 .957 'is a constant value that changes depending on the set reference temperature.

In addition, Equation 16 is obtained through Equation 15 obtained by the above-described tension test conditions, and generalized to Equation 17 below.

Here, F _C2 , F _C1 , and F _C0 of the right side term are constant values derived from the aforementioned T _C2 , T _C1 , and T _C0 .

That is, substituting the output voltage obtained through the tension change by the tension tester and the temperature value at the output voltage into Equation 15, and substituting the result obtained through this equation into Equation 16, converts the tension into the following table. It is equal to 2, and it can be seen from Table 2 that the tension obtained from Equation 16 and the tension applied in the actual tensile tester are coincident in the maximum error range of 5%.

Real tension Tension conversion value Average 12 ℃ 20 ℃ 28 ℃ 36 ℃ 43 ℃ 49 ℃ 55 ℃ 58 ℃ 0 3.27 -2.12 -1.64 -1.54 -1.34 -2.22 -1.83 -3.38 -1.36 10 14.93 10.46 11.27 11.68 11.57 11.37 10.46 8.75 11.31 20 23.30 19.35 20.39 20.70 21.32 21.01 20.18 18.73 20.62 30 32.40 29.10 30.16 30.69 30.90 31.12 30.58 28.99 30.49 40 41.38 38.22 39.74 40.29 40.83 41.16 40.62 39.20 40.18 50 49.56 47.44 49.00 50.00 50.90 51.12 50.34 48.89 49.65 60 57.55 57.09 58.23 59.48 60.51 61.08 60.28 59.14 59.17 70 66.73 66.61 68.47 69.75 70.45 70.68 71.03 69.05 69.09 80 76.56 77.16 78.70 79.77 81.56 81.80 81.32 80.13 79.62 90 92.31 88.30 89.51 90.73 91.21 92.55 92.92 91.58 91.14

FIG. 16 is a flowchart illustrating a derivation method of a tension calculation algorithm applied to a cable tension sensor according to an exemplary embodiment of the present invention, which summarizes a process of obtaining Equation 16 as described above.

First, in step S11, as shown in the results obtained through FIGS. 8 to 10, the magnetic field and the tension are applied to the cable 10, and the output voltage of the tension sensor 100 is measured accordingly. Next, in step S13, the strength of the magnetic field showing linearity and reproducibility in the characteristics of the output voltage with respect to the change in tension is checked based on the measurement result of step S11. Next, in step S15, the output of the power supply device 200 is adjusted so that the magnetic field obtained through the above-described step S13 is applied to the cable 10, and an artificial temperature change is applied to the cable 10 at the strength of the magnetic field and tension is applied. By applying a change in tension to the cable 10 through the tester, the output voltage of the tension sensor 100 according to the temperature and the tension change is measured.

Next, in step S17, an arbitrary temperature, that is, a reference temperature, is set among the temperatures changed in step S15, and in step S19, the voltage deviation between the output voltage at the reference temperature thus set and the output voltage at another temperature is calculated. . An example of such a step S19 is the aforementioned FIG. 13.

Next, in step S21, a temperature correction equation according to the temperature change is derived through the voltage deviation calculated through step S19, and the temperature correction equation is expressed in Equation 13. Next, in step S23 to derive an output voltage calculation formula for calculating the output voltage of the cable 10 in accordance with the change in tension at the reference temperature through the temperature correction formula derived through the above step S21, this output voltage calculation formula (15).

Finally, in step S25, the output voltage calculation formula obtained through step S23 is converted into a tension calculation formula that calculates tension through the input value using the voltage output from the tension sensor 100 as an input value. This results in Equation 16, which is a standardized tension calculation that yields a substantial tension that excludes temperature changes.

The tension calculation method and its derivation method applied to the cable tension sensor of the present invention are not limited to the above-described embodiments, and may be modified in various ways within the scope of the technical idea of the present invention.

According to the tension calculation method and the derivation method applied to the cable tension sensor of the present invention as described above, so that the electrical energy input from the tension sensor according to the magnetic field method is converted into a tension at a corresponding arbitrarily predetermined reference temperature By doing so, there is an effect of detecting a substantial change in tension applied to the cable.

Claims (3)

In the tension calculation method applied to the cable tension sensor applying a magnetic field artificially constant to the cable, and outputs the tension applied to the cable at a corresponding voltage based on the applied magnetic field, A temperature correction equation for calculating a deviation between the voltage output from the cable tension sensor and the output voltage of the cable tension sensor when the cable is a preset reference temperature

Wow; Output voltage calculation formula for calculating the output voltage of the cable tension sensor at the reference temperature through the temperature correction equation

Wow; A tension calculation equation that calculates the tension applied to the cable at the reference temperature based on the voltage output from the cable tension sensor and the cable temperature as an equation derived from the temperature correction equation and the output voltage calculation equation.

Tension is obtained by the above tension calculation formula, The V _O (t) is the output voltage of the cable tension sensor, the T is the temperature of the cable when the V _O (t) is output, the T _C2 and the T _C1 and T _C0 is the cable Is a constant value derived from the material and thickness of the magnetic field applied to the cable tension sensor and the reference temperature, and V _C is an initial voltage output from the cable tension sensor in a state where no magnetic field is applied to the cable. And F _C2 , F _C1, and F _C0 are constant values derived from the T _C2 , T _C1, and T _C0 . In the derivation method of the tension calculation method applied to the cable tension sensor for outputting the tension applied to the cable at a corresponding voltage based on the magnetic field applied to the cable, (A) applying a change in magnetic field and tension to the cable and measuring the output voltage of the cable tension sensor resulting from the change in magnetic field and tension; (B) extracting the strength of the magnetic field to have linearity in the characteristics of the output voltage measured in step (a); (C) measuring the output voltage of the cable tension sensor obtained by applying a change in temperature and tension to the cable artificially at the strength of the magnetic field extracted in step (b); (D) setting a reference temperature among the changed temperatures, and calculating a voltage deviation between the output voltage at the reference temperature and the output voltage at another temperature among the output voltages measured in the step (c); (E) deriving a temperature correction equation based on temperature change based on the voltage deviation calculated in step (d); (F) deriving an output voltage calculation formula for calculating an output voltage of the cable based on a change in tension at the reference temperature based on the temperature correction formula derived in step (e); And And (g) converting the output voltage calculation formula derived in the step (f) into a tension calculation formula for calculating the tension. The method of claim 2, The temperature correction formula derived in step (e)

Wherein T is the measured temperature of the cable, T _C2 and T _C1 and T _C0 is the material and thickness of the cable and the strength of the magnetic field applied to the cable tension sensor and set in step (d) Is a constant value derived from the reference temperature, The output voltage calculation formula derived in step (f)

Here, the V _O (t) is the voltage output from the cable tension sensor, the V _C is the initial voltage output from the cable tension sensor in the state that the magnetic field is not applied to the cable, The tension calculation formula derived in step (g)

Wherein, the F _C2 and the F _C1 and the F _C0 is a constant value derived from the T _C2 and T _C1 and T _C0 derived method of the tension calculation method applied to the cable tension sensor.

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