Strain measurement circuit based on strain gauge

Abstract

The present invention discloses a strain measurement circuit based on a strain gauge, the strain measurement circuit comprising: a bridge circuit, the bridge circuit comprising a strain gauge and a plurality of resistors, the strain gauge being connected to the plurality of resistors through a wire; an amplifier circuit, the input positive terminal and the input negative terminal of the amplifier circuit being respectively connected to the bridge circuit, the amplifier circuit being used to amplify the input measurement voltage signal to obtain an amplified measurement voltage signal; an offset compensation resistor; a processor, the input terminal of the processor being connected to the output terminal of the amplifier circuit, the output terminal of the processor being connected to the input positive terminal of the amplifier circuit through the offset compensation resistor, the processor being used to receive the amplified measurement voltage signal, and output the offset compensation voltage signal. The strain measurement circuit of the embodiment of the present invention can effectively measure and compensate for the error caused by the wire connecting the strain gauge and the plurality of resistors, thereby improving the measurement accuracy.

Description

Technical Field

[0001] The invention relates to the technical field of strain measurement, and in particular to a strain measurement circuit based on a strain gauge. Background Art

[0002] In strain measurement, the most common method is to use strain gauges to form a Wheatstone bridge for measurement. However, in engineering implementation, it is difficult to install the processing circuit near the location of the strain gauge, resulting in the strain gauge and the processing circuit being connected only by a long signal transmission line. The measurement error caused by the long signal transmission line cannot be ignored.

[0003] Among them, the longer signal transmission line resistance will cause the signal output by the strain gauge to have a larger potential offset, resulting in a larger offset in the output of the processing circuit, and even making it impossible to use the full output range of the strain gauge. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the above-mentioned technology at least to some extent.

[0005] To this end, an object of the present invention is to provide a strain measurement circuit based on a strain gauge, which can effectively measure and compensate for the errors caused by the wires connecting the strain gauge and multiple resistors, thereby improving the measurement accuracy.

[0006] To achieve the above-mentioned purpose, the first aspect of the present invention proposes a strain measurement circuit based on a strain gauge, comprising: a bridge circuit, the bridge circuit comprising the strain gauge and multiple resistors, the strain gauge being connected to the multiple resistors through a wire; an amplifier circuit, the input positive terminal and the input negative terminal of the amplifier circuit being respectively connected to the bridge circuit, the amplifier circuit being used to amplify the input measurement voltage signal to obtain an amplified measurement voltage signal; an offset compensation resistor; a processor, the input terminal of the processor being connected to the output terminal of the amplifier circuit, the output terminal of the processor being connected to the input positive terminal of the amplifier circuit through the offset compensation resistor, the processor being used to receive the amplified measurement voltage signal, and output an offset compensation voltage signal.

[0007] According to the strain measurement circuit based on the strain gauge of the embodiment of the present invention, the bridge circuit includes a strain gauge and multiple resistors, the strain gauge is connected to the multiple resistors through a wire, the input positive terminal and the input negative terminal of the amplifier circuit are respectively connected to the bridge circuit, the input measurement voltage signal is amplified by the amplifier circuit to obtain an amplified measurement voltage signal, the input terminal of the processor is connected to the output terminal of the amplifier circuit, the output terminal of the processor is connected to the first input terminal of the amplifier circuit through an offset compensation resistor, the amplified measurement voltage signal is received by the processor, and the offset compensation voltage signal is output. Therefore, the strain measurement circuit can effectively measure and compensate for the error caused by the wire connecting the strain gauge and the multiple resistors, thereby improving the measurement accuracy.

[0008] In addition, the strain measurement circuit based on the strain gauge proposed in the above embodiment of the present invention may also have the following additional technical features:

[0009] In one embodiment of the present invention, the multiple resistors include: a first resistor, a second resistor and a third resistor; the first end of the first resistor is used to input a power supply voltage signal, the second end of the first resistor is grounded through the strain gauge, and the second end of the first resistor is connected to the negative input terminal of the amplifier circuit; the first end of the second resistor is used to input the power supply voltage signal, the second end of the second resistor is grounded through the third resistor, and the second end of the second resistor is connected to the positive input terminal of the amplifier circuit.

[0010] In one embodiment of the present invention, the resistance value of the first resistor is equal to the resistance value of the second resistor, and the resistance value of the third resistor is equal to the resistance value of the strain gauge in a non-strained state.

[0011] In one embodiment of the present invention, the amplifying circuit includes: an amplifier, the positive input terminal of the amplifier serves as the positive input terminal of the amplifier circuit, the negative input terminal of the amplifier serves as the negative input terminal of the amplifier circuit, the output terminal of the amplifier serves as the output terminal of the amplifier circuit, and the amplifier is used to amplify the input measurement voltage signal to obtain the amplified measurement voltage signal; and a fourth resistor, the negative input terminal of the amplifier is connected to the output terminal of the amplifier through the fourth resistor.

[0012] In one embodiment of the present invention, the processor includes: an analog-to-digital converter, the input end of the analog-to-digital converter serves as the input end of the processor, and the analog-to-digital converter is used to perform analog-to-digital conversion processing on the input amplified measurement voltage signal to obtain an amplified measurement voltage value; a digital processor, the input end of the digital processor is connected to the output end of the analog-to-digital converter, and the digital processor is used to receive the amplified measurement voltage value and output an offset compensation voltage value; a digital-to-analog converter, the input end of the digital-to-analog converter is connected to the output end of the digital processor, the output end of the digital-to-analog converter serves as the output end of the processor, and the digital-to-analog converter is used to perform digital-to-analog conversion processing on the input offset compensation voltage value to obtain the offset compensation voltage signal.

[0013] In one embodiment of the present invention, the strain gauge-based strain measurement circuit further includes: a temperature acquisition device, which is disposed on the wire, connected to the digital processor, and used to acquire the temperature of the wire.

[0014] In one embodiment of the present invention, the digital processor is specifically used to: when the strain gauge is in a non-strain state, adjust the output offset compensation voltage value, and use the offset compensation voltage value corresponding to when the amplified measurement voltage value is equal to 0 as the target offset compensation voltage value.

[0015] In one embodiment of the present invention, the digital processor is also used to: when the strain gauge is in a strain state, adjust the output offset compensation voltage value to be equal to the target offset compensation voltage value; and determine the strain amount of the strain gauge based on the amplified measurement voltage value.

[0016] In one embodiment of the present invention, the digital processor is specifically used to: when the strain gauge is in a non-strain state, adjust the output offset compensation voltage value respectively at a plurality of different temperatures of the conductor, and use the offset compensation voltage value corresponding to when the amplified measurement voltage value is equal to 0 as the target offset compensation voltage value corresponding to the temperature of the conductor.

[0017] In one embodiment of the present invention, the digital processor is also used to: when the strain gauge is in a strain state, obtain the corresponding target offset compensation voltage value according to the temperature of the wire; adjust the output offset compensation voltage value to be equal to the corresponding target offset compensation voltage value; and determine the strain amount of the strain gauge according to the amplified measurement voltage value.

[0018] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0020] Figure 1 is a schematic diagram of a strain measurement circuit based on a strain gauge according to an embodiment of the present invention; and

[0021] Figure 2 is a schematic diagram of a strain measurement circuit based on a strain gauge according to another embodiment of the present invention. DETAILED DESCRIPTION

[0022] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0023] In the field of strain measurement, if the strain gauge and the processing circuit are connected by a long wire, it will inevitably cause non-negligible measurement errors during measurement. In order to measure and correct the errors caused by the long wire, the commonly used technical means, in addition to the strain gauge itself using a four-wire connection to eliminate the connection error, the relevant technology can also compensate by adding an external circuit.

[0024] However, the above method has the following disadvantages:

[0025] ① The entire bridge circuit needs to be placed near the strain gauge, which is difficult to achieve in engineering implementation;

[0026] ② There are many connections and the wiring is troublesome;

[0027] ③. The error introduced by the external circuit cannot be ignored, otherwise it will inevitably affect the accuracy of the measurement.

[0028] To this end, the present invention proposes a strain measurement circuit based on a strain gauge to at least solve one of the technical problems in the above-mentioned technology to a certain extent.

[0029] The strain measurement circuit based on the strain gauge according to the embodiment of the present invention is described below with reference to the accompanying drawings.

[0030] Figure 1 FIG. 1 is a schematic diagram of a strain measurement circuit based on a strain gauge according to an embodiment of the present invention. Figure 1 As shown, the strain measurement circuit based on the strain gauge according to the embodiment of the present invention may include: a bridge circuit 100 , an amplifying circuit 200 , an offset compensation resistor Rc and a processor 300 .

[0031] The bridge circuit 100 may include a strain gauge 110 and a plurality of resistors 120, and the strain gauge 100 is connected to the plurality of resistors 120 via a wire L. The positive input terminal and the negative input terminal of the amplifier circuit 200 are respectively connected to the bridge circuit 100, and the amplifier circuit 200 is used to amplify the input measurement voltage signal to obtain an amplified measurement voltage signal. The input terminal of the processor 300 is connected to the output terminal of the amplifier circuit 200, and the output terminal of the processor 300 is connected to the positive input terminal of the amplifier circuit 200 via an offset compensation resistor Rc. The processor 300 is used to receive the amplified measurement voltage signal and output the offset compensation voltage signal.

[0032] It should be noted that the number of the multiple resistors described in the above embodiments can be calibrated according to actual conditions.

[0033] Specifically, see Figure 1 , multiple resistors 120 and the strain gauge 100 form a bridge, and the multiple resistors 120 may include a first resistor R1, a second resistor R2, and a third resistor Rx, wherein the first end of the first resistor R1 is used to input a power supply voltage signal V+, the second end of the first resistor R1 is grounded through the strain gauge 110, and the second end of the first resistor R1 can also be connected to the negative input terminal of the amplifier circuit 200. The first end of the second resistor R2 is used to input a power supply voltage signal V+, the second end of the second resistor R2 is grounded through the third resistor Rx, and the second end of the second resistor R2 can also be connected to the positive input terminal of the amplifier circuit 200. The resistance value of the first resistor R1 and the resistance value of the second resistor R2 may be equal, and the resistance value of the third resistor Rx and the resistance value of the strain gauge 110 in a non-strained state may be equal.

[0034] See also Figure 1 The amplifier circuit 200 may include an amplifier AMP and a fourth resistor Rm, wherein the positive input terminal of the amplifier AMP serves as the positive input terminal of the amplifier circuit 200, the negative input terminal of the amplifier AMP serves as the negative input terminal of the amplifier circuit 200, and the output terminal of the amplifier AMP serves as the output terminal of the amplifier circuit 200. The amplifier AMP is used to amplify the input measurement voltage signal to obtain an amplified measurement voltage signal, and the negative input terminal of the amplifier AMP is connected to the output terminal of the amplifier AMP through the fourth resistor Rm.

[0035] See also Figure 1, the processor 300 may include an analog-to-digital converter ADC (Analog-to-Digital Converter), a digital processor MCU (Micro Control Unit) and a digital-to-analog converter DAC (Digital to analog converter), wherein the input end of the analog-to-digital converter ADC serves as the input end of the processor 300, and the analog-to-digital converter ADC is used to perform analog-to-digital conversion processing on the input amplified measurement voltage signal to obtain the amplified measurement voltage value. The input end of the digital processor MCU is connected to the output end of the analog-to-digital converter ADC, and the digital processor MCU is used to receive the amplified measurement voltage value and output the offset compensation voltage value. The input end of the digital-to-analog converter DAC is connected to the output end of the digital processor MCU, and the output end of the digital-to-analog converter DAC serves as the output end of the processor 300, and the digital-to-analog converter DAC is used to perform digital-to-analog conversion processing on the input offset compensation voltage value to obtain the offset compensation voltage signal.

[0036] The following describes in detail how the strain measurement circuit based on the strain gauge of the embodiment of the present invention compensates the wire guide:

[0037] In one embodiment of the present invention, the digital processor MCU is specifically used to adjust the output offset compensation voltage value when the strain gauge 110 is in a non-strain state, and use the offset compensation voltage value corresponding to when the amplified measured voltage value is equal to 0 as the target offset compensation voltage value.

[0038] Furthermore, in another embodiment of the present invention, the digital processor MCU is also used to adjust the output offset compensation voltage value to be equal to the target offset compensation voltage value when the strain gauge 110 is in a strain state, and determine the strain amount of the strain gauge according to the amplified measured voltage value.

[0039] For example, see Figure 1 , assuming that the current flowing through the first resistor R1 is I1, the current flowing through the strain gauge 110 is Is, wherein the resistance value of the strain gauge 110 is Rs, the resistance value of the wire L is r, the current flowing through the second resistor R2 is I2, the current flowing through the fourth resistor Rm is Im, the resistance change caused by strain is ΔR, the power supply voltage of the bridge circuit 100 is (V+)-(V-)=U, the input voltage of the positive input terminal of the amplifier circuit 200 is U2, the input voltage of the negative input terminal is U1, the compensation control voltage is Uc, the output voltage of the amplifier circuit 200 is Uo, and the power supply V- potential is 0.

[0040] When the strain gauge 110 is in a non-strained state, the network simultaneous equations consisting of the second resistor R2, the third resistor Rx and the offset compensation resistor Rc are:

[0041] U2=R2*I2;U2=Rc*Ic+Uc;(I2+Ic)*Rx=U-U2;From this we can obtain: U2=(R2RcU / R2-R2Uc) / (Rc+Rx+Rx*Rc / R2), then there exist constants: b2 and k2 which make U2=f(Uc)=k2Uc+b2 hold, that is, U2 and Uc have a linear relationship, among which, b2=(R2RcU / R2) / (Rc+Rx+Rx*Rc / R2), k2=-R2 / (Rc+Rx+Rx*Rc / R2).

[0042] When the strain gauge 110 is in a strain state, let Rs'=Rs+r+ΔR, and the network simultaneous equations formed by the first resistor R1, the resistance r of the wire L, the resistance Rs of the strain gauge 110 and the fourth resistor Rm are:

[0043] U1=Rs'*Is; U1=Rm*Im+Uo; (Is+Im)R1=U-U1; thus, Uo=(UmRm-U1(R1Rm / Rs'+R1+Rm)) / R1, and then according to the operational amplifier principle (i.e., the operation principle of the amplifier circuit 200), U1=U2, i.e., Uo=(UmRm-f(Uc)(R1Rm / Rs'+R1+Rm)) / R1. The same as the derivation process when the strain gauge 110 is in the non-strain state, the above formula can be simplified to: Uo=b1-f(Uc)k1 / Rs'=b1-f1(Uc)k1 / (Rs+r+ΔR), wherein Rs, k1 and b1 are constants.

[0044] From the monotonicity of f1(Uc), it can be seen that there is a certain control voltage value Uc that makes Uo=0 when ΔR=0 in the above formula, ensuring that the output of Uo does not exceed the sampling range of the analog-to-digital converter ADC during normal measurement, and can adapt to the influence of changes in line (conductor) length, thereby effectively measuring and compensating for the errors caused by the wires connecting the strain gauges and multiple resistors, thereby improving the measurement accuracy.

[0045] In addition, in one embodiment of the present invention, Figure 2 As shown, the strain gauge-based strain measurement circuit may further include a temperature acquisition device 10 , which is disposed on the conductor L and connected to a digital processor MCU. The temperature acquisition device 10 is used to acquire the temperature of the conductor L.

[0046] In one embodiment of the present invention, the digital processor MCU is specifically used to adjust the output offset compensation voltage value at the temperatures of multiple different wires L when the strain gauge 110 is in a non-strained state, and use the offset compensation voltage value corresponding to the amplified measured voltage value equal to 0 as the target offset compensation voltage value corresponding to the temperature of the wire.

[0047] Furthermore, in another embodiment of the present invention, the digital processor MCU is also used to obtain a corresponding target offset compensation voltage value according to the temperature of the wire L when the strain gauge 110 is in a strain state, and adjust the output offset compensation voltage value to be equal to the corresponding target offset compensation voltage value, and determine the strain amount of the strain gauge according to the amplified measured voltage value.

[0048] For example, see Figure 2 , assuming that the current flowing through the first resistor R1 is I1, the current flowing through the strain gauge 110 is Is, wherein the resistance value of the strain gauge 110 is Rs, the resistance value of the wire L is r, the current flowing through the second resistor R2 is I2, the current flowing through the fourth resistor Rm is Im, the resistance change caused by strain is ΔR, the power supply voltage of the bridge circuit 100 is (V+)-(V-)=U, the input voltage of the positive input terminal of the amplifier circuit 200 is U2, the input voltage of the negative input terminal is U1, the compensation control voltage is Uc, the output voltage of the amplifier circuit 200 is Uo, and the power supply V- potential is 0.

[0049] Based on the derivation process in the above example, the temperature of the wire L is taken into account, where, when the temperature variation range of the wire L is not large, the resistance of the metal wire (for example, the wire L) approximately meets r=r0+aT, where r0 is the resistance at 0°C, a is the temperature coefficient, and T is the current temperature.

[0050] Substituting the Uo formula in the above example into the Uo=, we can get Uo=b1-f(Uc)k1 / Rs'=b1-f1(Uc)k1 / (Rs+r0+aT+ΔR), that is, at different temperatures, there is a series of corresponding Uc, so that when ΔR=0 in the above formula, Uo=0, ensuring that during normal measurement, the output of Uo will not exceed the sampling range of the analog-to-digital converter ADC, and can adapt to the influence of changes in line (conductor) length, thereby effectively measuring and compensating for the errors caused by the wires connecting the strain gauges and multiple resistors, thereby improving the measurement accuracy.

[0051] It should be noted that when the compensation control voltage Uc is a fixed value, the calibration process is:

[0052] First, confirm that the strain gauge 110 is in a stable state (i.e., the resistance value of the strain gauge 110 is in a stable state), ΔR=0, and set the DAC value of the digital-to-analog converter so that the compensation control voltage Uc is output from low to high within a certain output range. At the same time, collect the output value Uo of the operational amplifier (amplifier circuit 200). When Uo=0, save the current DAC value of the digital-to-analog converter.

[0053] Then, by repeating the above process at different temperatures, a series of compensation control voltages Uc corresponding to the temperature can be obtained. In actual use, the temperature near the wire is collected by the temperature sensor 10, and the corresponding compensation control voltage Uc is output to complete the compensation.

[0054] The strain measurement based on the strain gauge in the embodiment of the present invention can compensate for the errors in the measurement process and is relatively flexible. It can not only compensate for the resistance of long wires, but also compensate for the measurement errors caused by temperature and the measurement errors caused by component parameter errors in other measurement circuits. It can also effectively reduce the number of wiring harnesses. One strain gauge only needs 2 wires, and multi-channel measurement expansion can be conveniently performed on the circuit.

[0055] In summary, according to the strain measurement circuit based on the strain gauge of the embodiment of the present invention, the bridge circuit includes a strain gauge and multiple resistors, the strain gauge is connected to the multiple resistors through a wire, the input positive terminal and the input negative terminal of the amplifier circuit are respectively connected to the bridge circuit, the input measurement voltage signal is amplified by the amplifier circuit to obtain an amplified measurement voltage signal, the input terminal of the processor is connected to the output terminal of the amplifier circuit, the output terminal of the processor is connected to the first input terminal of the amplifier circuit through an offset compensation resistor, the amplified measurement voltage signal is received by the processor, and the offset compensation voltage signal is output. Therefore, the strain measurement circuit can effectively measure and compensate for the error caused by the wire connecting the strain gauge and the multiple resistors, thereby improving the measurement accuracy.

[0056] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0057] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0058] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0059] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0060] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0061] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A strain measurement circuit based on a strain gauge, characterized in that: include: A bridge circuit, the bridge circuit comprising the strain gauge and a plurality of resistors, the strain gauge being connected to the plurality of resistors via a wire; an amplifier circuit, wherein the input positive terminal and the input negative terminal of the amplifier circuit are respectively connected to the bridge circuit, and the amplifier circuit is used to amplify the input measurement voltage signal to obtain an amplified measurement voltage signal; Offset compensation resistor; A processor, the processor is used to receive the amplified measurement voltage signal and output an offset compensation voltage signal, the processor includes an analog-to-digital converter ADC, a digital processor MCU and a digital-to-analog converter DAC, the output end of the amplifier circuit is connected to the input end of the analog-to-digital converter ADC, the output end of the analog-to-digital converter ADC is connected to the input end of the digital processor MCU, the output end of the digital processor MCU is connected to the input end of the digital-to-analog converter DAC, and the output end of the digital-to-analog converter DAC is connected to the input positive end of the amplifier circuit through the offset compensation resistor; The digital processor is specifically used to: when the strain gauge is in a non-strained state, adjust the output offset compensation voltage value, and use the offset compensation voltage value corresponding to when the amplified measurement voltage value is equal to 0 as the target offset compensation voltage value; When the strain gauge is in a strain state, the offset compensation voltage value output is adjusted to be equal to the target offset compensation voltage value, and the strain amount of the strain gauge is determined according to the amplified measurement voltage value.

2. The strain measurement circuit according to claim 1, characterized in that: The plurality of resistors include: a first resistor, a second resistor and a third resistor; The first end of the first resistor is used to input a power supply voltage signal, the second end of the first resistor is grounded through the strain gauge, and the second end of the first resistor is connected to the negative input end of the amplifier circuit; The first end of the second resistor is used to input the power supply voltage signal, the second end of the second resistor is grounded through the third resistor, and the second end of the second resistor is connected to the positive input end of the amplifier circuit.

3. The strain measurement circuit according to claim 2, characterized in that: The resistance value of the first resistor is equal to the resistance value of the second resistor, and the resistance value of the third resistor is equal to the resistance value of the strain gauge in a non-strained state.

4. The strain measurement circuit according to claim 1, characterized in that: The amplifying circuit comprises: An amplifier, wherein the positive input terminal of the amplifier serves as the positive input terminal of the amplifier circuit, the negative input terminal of the amplifier serves as the negative input terminal of the amplifier circuit, and the output terminal of the amplifier serves as the output terminal of the amplifier circuit, and the amplifier is used to amplify the input measurement voltage signal to obtain the amplified measurement voltage signal; A fourth resistor, the negative input terminal of the amplifier is connected to the output terminal of the amplifier through the fourth resistor.

5. The strain measurement circuit according to claim 1, characterized in that: The analog-to-digital converter is used to perform analog-to-digital conversion processing on the input amplified measurement voltage signal to obtain an amplified measurement voltage value; The digital-to-analog converter is used to perform digital-to-analog conversion processing on the input offset compensation voltage value to obtain the offset compensation voltage signal.

6. The strain measurement circuit according to claim 1, characterized in that: Also includes: A temperature acquisition device is arranged on the wire, connected to the digital processor, and used to acquire the temperature of the wire.

7. The strain measurement circuit according to claim 6, characterized in that: The digital processor is specifically used for: When the strain gauge is in a non-strained state, the output offset compensation voltage value is adjusted respectively at multiple different temperatures of the conductor, and the offset compensation voltage value corresponding to the amplified measurement voltage value equal to 0 is used as the target offset compensation voltage value corresponding to the temperature of the conductor.

8. The strain measurement circuit according to claim 7, characterized in that: The digital processor is also used to: When the strain gauge is in a strain state, obtaining the corresponding target offset compensation voltage value according to the temperature of the wire; The offset compensation voltage value of the adjustment output is equal to the corresponding target offset compensation voltage value; The strain amount of the strain gauge is determined according to the amplified measured voltage value.

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