Force transducer amplifying circuit with adjustable gain

Abstract

The invention discloses a force transducer amplifying circuit with adjustable gain, which comprises two stages of amplifying circuits which are a first-stage instrument operation amplifying circuit and a second-stage in-phase amplifying circuit; the filter circuit is connected with the two-stage amplifier circuit and is used for filtering high-frequency noise and low-frequency drift; wherein the first-stage instrument operation amplification circuit is arranged close to a sensor interface and is used for reducing noise, the second-stage in-phase amplification circuit is used for continuously adjusting gain, the total gain range is 1234.8-1646.4 times, millivolt-level signals output by the low-sensitivity force sensor can be amplified, the output signals can reach the proper amplitude, and the low-sensitivity force sensor can be controlled to be stable. The cut-off frequency of the first-stage filter is 15.9 kHz, high-frequency noise in differential signals of the force sensor can be effectively filtered out, and the influence of high-frequency interference on signal amplification and subsequent processing is avoided.

Description

Technical Field

[0001] This invention relates to the field of force sensor amplifier circuit technology, and in particular to a force sensor amplifier circuit with adjustable gain. Background Technology

[0002] In the field of force sensor technology, the millivolt-level voltage signal output by the force sensor needs to be amplified, filtered and output; the design of the amplifier circuit is the core key technology. Currently, the gain of the commonly used amplifier circuits in this field is less than 1000 times, which cannot meet the signal amplification requirements of some low-sensitivity force sensors.

[0003] This invention provides a high-gain force sensor amplifier circuit. The circuit mainly comprises two amplifier stages. The first stage uses an integrated instrumentation operational amplifier to amplify the millivolt-level voltage from the force sensor. The second stage, connected to the output of the first stage's instrumentation operational amplifier, employs a high-precision operational amplifier design to amplify the signal output from the first stage's instrumentation operational amplifier a second time. These two amplifier stages amplify the millivolt-level voltage twice, and the amplification factor can be adjusted using a potentiometer. Using this invention's two-stage amplifier design, the final gain of the circuit can be increased to 1234.8 to 1646.4 times. Summary of the Invention

[0004] This application provides a force sensor amplifier circuit with adjustable gain, with a total gain range of 1234.8 to 1646.4 times. It can fully amplify the millivolt-level signal output by a low-sensitivity force sensor, so that the output signal reaches a suitable amplitude. The first-stage filter has a cutoff frequency of 15.9 kHz, which can effectively filter out high-frequency noise in the differential signal of the force sensor and avoid the influence of high-frequency interference on signal amplification and subsequent processing.

[0005] This application provides a force sensor amplifier circuit with adjustable gain, including: a two-stage amplifier circuit, wherein the two-stage amplifier circuit is a first-stage instrument operational amplifier circuit and a second-stage in-phase amplifier circuit;

[0006] A filter circuit, connected to the two-stage amplifier circuit, is used to filter out high-frequency noise and low-frequency drift;

[0007] The first-stage instrument operational amplifier circuit is positioned close to the sensor interface to reduce noise, while the second-stage in-phase amplifier circuit is used for continuous gain adjustment.

[0008] Preferably, the first-stage instrumentation operational amplifier circuit includes an instrumentation operational amplifier and a low-pass filter, wherein the instrumentation operational amplifier is used for amplification and high common-mode rejection ratio;

[0009] The low-pass filter consists of resistors and capacitors and is used to filter out high-frequency interference noise.

[0010] The instrument operational amplifier receives the differential signal from the force sensor at its input terminal and is connected to a low-pass filter at its output terminal.

[0011] Preferably, the cutoff frequency of the low-pass filter is calculated using the following formula: Among them, F c The cutoff frequency is defined by R256 and R257, which are resistors with equal resistance values. C4 and C13 are capacitors with equal capacitance values.

[0012] Preferably, the second-stage non-inverting amplifier circuit includes a non-inverting amplifier and an adjustable resistor network;

[0013] The adjustable resistor network consists of resistors and potentiometers, used for continuous gain adjustment;

[0014] The non-inverting input of the non-inverting amplifier receives the output signal of the first-stage instrumentation operational amplifier circuit, while the inverting input is grounded through a reference resistor.

[0015] Preferably, the amplification gain of the second-stage in-phase amplifier circuit is: Where G2 is the amplification factor of the second-stage non-inverting amplifier circuit, and R... f R represents the total resistance of the feedback network. f = R2 + W1, where R2 and W1 are the resistor and potentiometer of the adjustable resistor network, R f Together with R1, they form a feedback voltage divider network. R1 is the grounding resistor for the inverting input terminal, a reference resistor connected between the inverting input terminal of the op-amp and ground, used to provide a reference for gain calculation.

[0016] Preferably, the filtering circuit is an active low-pass filter, which consists of an operational amplifier, resistors and capacitors, and is used to filter out high-frequency noise amplified by the second-stage inverting amplifier circuit;

[0017] The operational amplifier is configured as a voltage follower, with its input connected to the output of the second-stage non-inverting amplifier circuit and its output providing a filtered signal.

[0018] Preferably, it also includes a method for constructing a simulation correction model and a drift trend prediction model:

[0019] S101 collects the parameters of the force sensor and constructs a simulation correction model based on the force sensor parameters, amplification circuit, and filtering circuit.

[0020] S102: Collect historical operating data of the amplifier circuit, construct a drift trend prediction model, perform frequency domain characteristic analysis on the predicted future gain drift value, extract frequency features, construct a frequency feature library based on the frequency domain features, compare the drift trend predicted by the drift trend prediction model with the frequency feature library, if the measured drift trend is not within the range of the frequency feature library, bring the predicted drift trend back into the simulation correction model, generate correction parameters, and correct the drift trend prediction model parameters based on the correction parameters.

[0021] One or more technical solutions provided in this application have at least the following technical effects or advantages: the total gain range is from 1234.8 to 1646.4 times, which can fully amplify the millivolt-level signal output by the low-sensitivity force sensor, so that the output signal reaches a suitable amplitude; the cutoff frequency of the first-stage filter is 15.9kHz, which can effectively filter out high-frequency noise in the differential signal of the force sensor and avoid the influence of high-frequency interference on signal amplification and subsequent processing; the cutoff frequency of the filter circuit is 15.9Hz, which can filter out low-frequency noise, ensure smooth output voltage, and improve the stability of output signal; amplifying the millivolt-level differential signal output by the force sensor to a high-gain voltage signal while ensuring high accuracy and anti-interference, it is suitable for force sensor amplification circuits, especially for low-sensitivity force measurement scenarios, and realizes a force sensor amplification circuit with high gain (total gain up to 1646.4 times), high accuracy (stable performance of domestic components, adjustable gain to improve adaptability), and high stability (effective noise suppression by filter design, reliable output signal), and supports the domestic supply chain, reducing costs;

[0022] By constructing a drift trend prediction model and a simulation correction model, the long-term drift problem can be solved, improving the long-term stability, accuracy and adaptability of the force sensor amplifier circuit, reducing hardware and maintenance costs, enabling predictive maintenance, and enhancing product performance and market competitiveness. Attached Figure Description

[0023] Figure 1 This is a circuit diagram of the first-stage instrument operational amplifier circuit of the present invention;

[0024] Figure 2 This is a circuit diagram of the second-stage inverting amplifier circuit of the present invention;

[0025] Figure 3 This is a circuit diagram of the filter circuit of the present invention;

[0026] Figure 4 This is a schematic diagram illustrating the process of constructing the simulation correction model and the drift trend prediction model for this invention. Detailed Implementation

[0027] To facilitate understanding of the present invention, a more complete description of this application will be given below with reference to the accompanying drawings, which illustrate preferred embodiments of the invention. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to enable a more thorough and complete understanding of the disclosure of the present invention.

[0028] It should be noted that the terms "vertical," "horizontal," "up," "down," "left," "right," and similar expressions used in this article are for illustrative purposes only and do not represent the only possible implementation.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to limit the invention; the term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0030] Example 1: Figure 1 This is a circuit diagram of a gain-adjustable force sensor amplifier circuit according to an embodiment of the present invention, including: a two-stage amplifier circuit and a filter circuit. The two-stage amplifier circuit includes an instrumentation operational amplifier and a high-precision non-inverting amplifier. The instrumentation operational amplifier and a low-pass filter constitute the first-stage instrumentation operational amplifier circuit, and the high-precision non-inverting amplifier, resistors, and potentiometer constitute the second-stage non-inverting amplifier circuit. In the printed circuit board (PCB), the first-stage instrumentation operational amplifier circuit is located close to the sensor interface to reduce noise introduction. The low-pass filter components are compactly laid out to avoid long traces. Decoupling capacitors (C4 and C13) are added to the low-pass filter to enhance power supply noise suppression.

[0031] like Figure 1 In the first-stage instrumentation operational amplifier circuit shown, the instrumentation operational amplifier is selected as the FX620 model for high common-mode rejection ratio and precise amplification. The low-pass filter consists of resistor R256, capacitor C4, resistor R257, and capacitor C13, used to filter out high-frequency interference noise. The first-stage instrumentation operational amplifier circuit receives the differential input signal from the force sensor, first filters out high-frequency noise through the low-pass filter, and then amplifies it with high gain through the instrumentation operational amplifier. The force sensor output is a millivolt-level differential voltage signal, which is input to the first-stage instrumentation operational amplifier circuit through pins S1- and S1+. The differential voltage signal is used to suppress common-mode noise and improve signal integrity. The differential voltage signal is filtered by the low-pass filter. The formula for calculating the cutoff frequency of the low-pass filter is: Among them, F cTo achieve the cutoff frequency, resistors R256 and R257 have the same resistance value, and capacitors C4 and C13 have the same capacitance value. The filtered differential voltage signal is then input to the FX620 instrumentation operational amplifier for amplification, with the following amplification factor: Where G1 is the amplification factor of the first-stage instrumentation operational amplifier circuit, and R... i R is the internal resistor of the FX620. i =49.4kΩ, RG is the resistor for setting the external gain; the amplified signal is output from the FX620 output terminal as the input of the second-stage non-inverting amplifier circuit.

[0032] like Figure 2 The second-stage non-inverting amplifier circuit shown includes a high-precision non-inverting amplifier F2284, a resistor R2, and a potentiometer W1. The high-precision non-inverting amplifier F2284 features low noise, high input impedance, stable gain characteristics, and good linearity. The high input impedance prevents the amplifier F2284 from causing a load effect on the preceding circuit. The stable gain characteristics ensure that the gain of the second-stage amplifier circuit is determined solely by the external resistor network and is independent of the operational amplifier's own parameters. Good linearity ensures no distortion during signal amplification. The fixed resistor R2 serves as a reference resistor, and the potentiometer W1 is an adjustable resistor with a resistance range of 2kΩ to 4kΩ, used to achieve continuous gain adjustment. The formula for the adjustable gain of the potentiometer W1 is: Where G2 is the amplification factor of the second-stage non-inverting amplifier circuit, and R... f R represents the total resistance of the feedback network and is a key parameter that determines the amplification factor. f =R2+W1,R f Together with R1, they form a feedback voltage divider network to control the closed-loop gain of the operational amplifier. R1 is the grounding resistor for the inverting input terminal, a reference resistor connected between the inverting input terminal of the operational amplifier and ground, used to provide a reference for gain calculation; its accuracy directly affects the accuracy of the gain. The second-stage non-inverting amplifier circuit receives the output signal from the first-stage instrumentation operational amplifier circuit. The output signal of the first-stage instrumentation operational amplifier circuit is an amplified single-ended voltage signal with an amplitude reaching the hundreds of millivolts level. The output signal of the first-stage instrumentation operational amplifier circuit is connected to the non-inverting input (+) terminal of the high-precision non-inverting amplifier F2284. The amplified voltage is: U o =G2×U i Where G2 is the amplification factor of the second-stage non-inverting amplifier circuit, and U i U is the output signal of the first-stage operational amplifier circuit, which is also the input signal of the second-stage non-inverting amplifier circuit. o This is the output voltage of the second-stage non-inverting amplifier circuit.

[0033] The total gain is calculated based on the amplification factor of the first-stage operational amplifier circuit and the amplification factor of the second-stage non-inverting amplifier circuit, using the formula: G t = G1 × G2, where G t G1 is the total gain of the amplifier circuit, G2 is the gain of the first-stage instrumentation operational amplifier circuit, and G2 is the gain of the second-stage non-inverting amplifier circuit. For the resistors R2 and R1 in the above circuit, metal film resistors with an accuracy of 1% are selected to ensure the accuracy of the calculation. The high-precision non-inverting amplifier F2284 has a built-in temperature compensation circuit to reduce the impact of temperature drift. The amplifier F2284 has a sufficient gain-bandwidth product to ensure stable operation within the target frequency range.

[0034] like Figure 3 As shown, the filter circuit consists of an F2284 operational amplifier, capacitors, and resistors. The F2284 operational amplifier has low offset voltage and high open-loop gain, making it suitable for constructing active filters. The resistors and capacitors are connected in series to form an RC filter network. This RC filter network is connected to the feedback loop of the operational amplifier to form a first-order active low-pass filter circuit. The output of the second-stage non-inverting amplifier circuit is used as the input of the filter circuit. The F2284 operational amplifier is configured as a voltage follower or a buffer with a gain of 1. It mainly utilizes its high input impedance and low output impedance characteristics to achieve filtering and isolation. The signal after the second-stage amplification contains high-frequency noise introduced during the amplification process. The filter circuit, based on the low impedance presented by the RC filter network for high-frequency signals, shuns the high-frequency signals to ground; the low-frequency signals pass through the operational amplifier without loss. The filtered signal is output from the output terminal of the F2284 operational amplifier. The output amplitude is the same as the input, but the noise is suppressed. Compared with passive filters, active design provides gain isolation, avoiding the load effect of subsequent circuits from affecting the amplification of the preceding stage.

[0035] A specific example is an industrial force measurement application scenario: the force sensor is a low-sensitivity strain gauge force sensor with a small output differential signal amplitude, typically 1mV (at full scale). This 1mV signal needs to be amplified to the volt level for data acquisition card processing, while also requiring high accuracy and interference resistance. The force sensor outputs a 1mV differential voltage, which is input to the first-stage circuit through pins S1- and S1+. The differential design suppresses common-mode noise (such as environmental electromagnetic interference). The signal first passes through a low-pass filter composed of R256, C4, R257, and C13, where R256 = R257 = 1kΩ, C4 = C13 = 10nF. After filtering, high-frequency noise is attenuated, preserving the valid sensor signal. The filtered signal is then input to the FX620 instrumentation operational amplifier, and its gain is determined by an external resistor RG = 120Ω. The first stage output is U, which is a 1mV input signal. i=1mV × 411.6 = 411.6mV. This output serves as the input for the second stage. In the PCB layout, the first stage is located close to the sensor interface. Decoupling capacitors C4 and C13 enhance power supply noise suppression to ensure signal purity. The first stage output Ui = 411.6mV is connected to the second stage F2284 non-inverting amplifier. The gain is adjustable via potentiometer W1 (resistance adjustable from 2kΩ to 4kΩ). R1 = 1kΩ, minimum gain is when W1 = 2kΩ, R f =2kΩ, Times; when the maximum gain is W1 = 4kΩ, R f =4kΩ, When W1 is adjusted to the middle value (e.g., 3kΩ), If the gain is multiplied by a factor of 1 (taking the maximum gain example), then: U o = 411.6mV × 4 = 1646.4mV ≈ 1.65V, the total gain is verified to be G. t =G1×G2=411.6×4=1646.4 times; The second-stage output Uo=1.65V (possibly containing high-frequency noise) is connected to the filter. The RC network (R=10kΩ, C=1μF) constitutes a first-order active low-pass filter with a cutoff frequency of 15.9Hz. This frequency is optimized for the low-frequency characteristics of the force sensor, retaining the fundamental frequency of the signal (usually <10Hz) and filtering out high-frequency noise. The F2284 is configured as a voltage follower, with the output amplitude being the same as the input (1.65V), but the noise is suppressed. The input signal contains 100Hz noise, which the filter attenuates by -20dB / decade, resulting in an attenuation of approximately -12dB at 100Hz, significantly improving the output signal-to-noise ratio.

[0036] The technical solutions described in the embodiments of this application have at least the following technical effects or advantages: the total gain range is from 1234.8 to 1646.4 times, which can fully amplify the millivolt-level signal output by the low-sensitivity force sensor, so that the output signal reaches a suitable amplitude; the cutoff frequency of the first-stage filter is 15.9kHz, which can effectively filter out high-frequency noise in the differential signal of the force sensor, avoiding the influence of high-frequency interference on signal amplification and subsequent processing; the cutoff frequency of the filter circuit is 15.9Hz, which can filter out low-frequency noise, ensure smooth output voltage, and improve the stability of the output signal; the millivolt-level differential signal output by the force sensor is amplified to a high-gain voltage signal, while ensuring high accuracy and anti-interference, which is suitable for force sensor amplification circuits, especially for low-sensitivity force measurement scenarios, realizing a high-gain (total gain up to 1646.4 times), high-precision (stable performance of domestic components, adjustable gain improves adaptability), and high-stability (filter design effectively suppresses noise, and the output signal is reliable) force sensor amplification circuit, and supports the domestic supply chain, reducing costs.

[0037] Example 2: Based on the two-stage amplifier circuit of Example 1, this example introduces digital twin correction and intelligent sensing algorithms to upgrade from static gain adjustment to dynamic self-correction, such as... Figure 4 As shown.

[0038] S101 collects the parameters of the force sensor and constructs a simulation correction model based on the force sensor parameters, amplification circuit, and filtering circuit.

[0039] Specifically, an environment with adjustable temperature is set up, with the temperature range set between -10℃ and +60℃. Starting from -10℃, the temperature is gradually increased to +60℃ at certain temperature intervals (e.g., 5℃). Under each set temperature condition, a signal generator is used to apply different input signals to the force sensor amplifier circuit (simulating different load conditions). A data acquisition card is used to collect the temperature, time, load, and output signals of the force sensor. The collected data is stored in a feature database. MATLAB is used to construct a simulation correction model corresponding to the physical circuit. A Kalman filter state estimation algorithm is used to establish a dynamic mapping relationship between the simulation correction model and the physical circuit. That is, regardless of how the physical circuit changes under different temperature, load, and time conditions, the simulation correction model can accurately simulate the corresponding state in real time. The simulation correction model simulates ideal output characteristics, which are set based on the output of the force sensor under ideal conditions and the ideal gain and filtering effect of the amplifier and filter circuits. The parameters of the simulation correction model are adjusted to make its output signal close to the signal of the physical circuit. By continuously optimizing the model parameters, the error of the corrected circuit is reduced.

[0040] S102: Collect historical operating data of the amplifier circuit, construct a drift trend prediction model, perform frequency domain characteristic analysis on the predicted future gain drift value, extract frequency features, construct a frequency feature library based on the frequency domain features, compare the drift trend predicted by the drift trend prediction model with the frequency feature library, if the measured drift trend is not within the range of the frequency feature library, bring the predicted drift trend back into the simulation correction model, generate correction parameters, and correct the drift trend prediction model parameters based on the correction parameters;

[0041] Furthermore, a high-precision data acquisition card (NIPCIe-6363) is connected to the output of the second-stage inverting amplifier circuit. The sampling rate is set to 1MHz and the resolution to 16-bit. Data from the temperature sensor (PT100), load simulator (programmable electronic load), and clock module are acquired simultaneously to ensure spatiotemporal alignment of multiple parameters. The data acquisition card continuously acquires historical data for 12 months, recording a complete parameter set every 5 minutes. Based on the historical operating data acquired above, a drift trend prediction model is constructed using a Long Short-Term Memory (LSTM) network. The drift trend prediction model includes an input layer and an output layer, which are temperature, load, time, and historical output signals. The output layer is the gain drift prediction value for the next 72 hours. The historical operating data is divided into a training set and a validation set. The training set is the data from the previous 10 months, and the validation set is the data from the last 2 months. The drift trend prediction model is trained using the training set. The temperature, load, time, and historical output signals are input into the trained drift trend prediction model. After the drift trend prediction model performs calculations according to its internal algorithm, it outputs the future gain drift prediction value.

[0042] The physical characteristics of the output future gain drift prediction are set to a frequency band (e.g., 0.001Hz to 1Hz). High-frequency noise and low-frequency drift are filtered out. The Hammin window function is used to reduce spectral leakage. The number of sampling points for the FFT (Fourier Transform) is set. Frequency characteristics such as amplitude, phase, harmonic distortion rate, noise power spectral density, and drift rate of the gain drift prediction are extracted. The amplitude is the magnitude of the periodic component of the gain drift, and the phase is the phase angle of the main frequency component relative to the reference time (0 point). The formula for calculating the harmonic distortion rate is: Where THD is the harmonic distortion rate, representing the ratio of the total power of all harmonic components in the signal to the fundamental power; P1 is the fundamental power, the power of the lowest frequency (i.e., the dominant frequency) harmonic component in the signal; P... nThe power of the nth harmonic is the power of the harmonic component in the signal whose frequency is n times the fundamental frequency, where n is the harmonic order and N is the highest harmonic order. The noise power spectral density is estimated using the Welch method, with the segment length set to one-quarter of the number of Fourier sampling points. The total gain change within the predicted time period is extracted, i.e., the drift rate is extracted. The operating conditions are divided according to the frequency characteristics of the predicted gain drift value. The operating conditions include temperature range, load level, and time scale. The temperature range is divided into low temperature, normal temperature, and high temperature. The load level is divided into no load, light load, and full load. The time scale is divided into short-term, medium-term, and long-term. The above operating conditions are combined, and the frequency domain features are stored in the frequency feature library according to different combinations of operating conditions. The feature library is queried according to the current operating condition (e.g., temperature 25℃, load 50%, prediction 24 hours) to obtain the corresponding drift characteristic threshold. If the actual predicted value of THD exceeds the threshold in the library, or the high-frequency component of PSD suddenly increases, an alarm is triggered, and the predicted drift trend is brought back to the simulation correction model to generate correction parameters. The drift trend prediction model is corrected according to the correction parameters.

[0043] The technical solutions described in the above embodiments of this application have at least the following technical effects or advantages: by constructing a drift trend prediction model and a simulation correction model, the long-term drift problem is solved, the long-term stability, accuracy and adaptability of the force sensor amplification circuit are improved, hardware costs and maintenance costs are reduced, predictive maintenance is achieved, and product performance and market competitiveness are enhanced.

[0044] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A force sensor amplifier circuit with adjustable gain, characterized in that, include: A two-stage amplifier circuit, wherein the two-stage amplifier circuit is a first-stage instrumentation operational amplifier circuit and a second-stage non-inverting amplifier circuit; A filter circuit, connected to the two-stage amplifier circuit, is used to filter out high-frequency noise and low-frequency drift; The first-stage instrument operational amplifier circuit is positioned close to the sensor interface to reduce noise, while the second-stage in-phase amplifier circuit is used for continuous gain adjustment.

2. The gain-adjustable force sensor amplifier circuit as described in claim 1, characterized in that, The first-stage instrumentation operational amplifier circuit includes an instrumentation operational amplifier and a low-pass filter. The instrumentation operational amplifier is used for high common-mode rejection ratio and amplification. The low-pass filter consists of resistors and capacitors and is used to filter out high-frequency interference noise. The instrument operational amplifier receives the differential signal from the force sensor at its input terminal and is connected to a low-pass filter at its output terminal.

3. The force sensor amplifier circuit with adjustable gain as described in claim 2, characterized in that, The formula for calculating the cutoff frequency of the low-pass filter is as follows: Among them, F c The cutoff frequency is defined by R256 and R257, which are resistors with equal resistance values. C4 and C13 are capacitors with equal capacitance values.

4. The gain-adjustable force sensor amplifier circuit as described in claim 1, characterized in that, The second-stage non-inverting amplifier circuit includes a non-inverting amplifier and an adjustable resistor network; The adjustable resistor network consists of resistors and potentiometers, used for continuous gain adjustment; The non-inverting input of the non-inverting amplifier receives the output signal of the first-stage instrumentation operational amplifier circuit, while the inverting input is grounded through a reference resistor.

5. The gain-adjustable force sensor amplifier circuit as described in claim 4, characterized in that, The amplification gain of the second-stage non-inverting amplifier circuit is: Where G2 is the amplification factor of the second-stage non-inverting amplifier circuit, and R... f R represents the total resistance of the feedback network. f = R2 + W1, where R2 and W1 are the resistor and potentiometer of the adjustable resistor network, R f Together with R1, they form a feedback voltage divider network. R1 is the grounding resistor for the inverting input terminal, a reference resistor connected between the inverting input terminal of the op-amp and ground, used to provide a reference for gain calculation.

6. The force sensor amplifier circuit with adjustable gain as described in claim 1, characterized in that, The filtering circuit is an active low-pass filter, consisting of an operational amplifier, resistors, and capacitors, used to filter out high-frequency noise amplified by the second-stage inverting amplifier circuit. The operational amplifier is configured as a voltage follower, with its input connected to the output of the second-stage non-inverting amplifier circuit and its output providing a filtered signal.

7. The force sensor amplifier circuit with adjustable gain as described in claim 1, characterized in that, It also includes methods for constructing simulation correction models and drift trend prediction models: S101 collects the parameters of the force sensor and constructs a simulation correction model based on the force sensor parameters, amplification circuit, and filtering circuit. S102: Collect historical operating data of the amplifier circuit, construct a drift trend prediction model, perform frequency domain characteristic analysis on the predicted future gain drift value, extract frequency features, construct a frequency feature library based on the frequency domain features, compare the drift trend predicted by the drift trend prediction model with the frequency feature library, if the measured drift trend is not within the range of the frequency feature library, bring the predicted drift trend back into the simulation correction model, generate correction parameters, and correct the drift trend prediction model parameters based on the correction parameters.

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