Dual-mode resonant sensor and closed-loop control method thereof

Abstract

The invention provides a dual-mode resonant sensor, and relates to the technical field of sensors, and the dual-mode resonant sensor comprises a single resonator, two sides of a resonant beam of the single resonator are provided with a first differential detection electrode pair, a second differential detection electrode pair and a driving electrode pair; the first differential detection electrode pair is symmetrically arranged on two sides of the middle part of the resonant beam and is used for detecting a first-order modal vibration signal of the single resonator; the second differential detection electrode pair is symmetrically arranged at two ends of one side of the resonant beam and is used for detecting a second-order modal vibration signal of the single resonator; the driving electrode pair is arranged at two ends of the other side of the resonant beam and is used for applying an alternating current driving signal to the resonant beam; the closed-loop control circuit is connected with the first differential detection electrode pair through a pair of first input ends and connected with the second differential detection electrode pair through a pair of second input ends, the output end of the closed-loop control circuit is connected with the driving electrode pair, and the closed-loop control circuit is used for feeding back and adjusting the alternating current driving signal according to the first-order modal vibration signal and / or the second-order modal vibration signal. The invention further provides a closed-loop control method.

Description

Technical Field

[0001] The present application relates to the field of sensor technology, and more specifically, to a dual-mode resonant sensor and a closed-loop control method thereof. Background Art

[0002] Resonant sensors are high-performance sensors based on the resonance principle. Their core advantages lie in high precision, high sensitivity, strong anti-interference capabilities, and low power consumption. These sensors sense changes in external physical quantities, such as pressure, acceleration, and density, by detecting changes in resonant frequency. Their output signal is a periodic frequency signal, making it easy to connect to a computer and transmit over long distances. The sensor system also employs a closed-loop structure, with the output automatically tracking the input to ensure measurement stability. Due to the resonator's low vibration energy, the system consumes extremely low power. Its high sensitivity and resolution also enable excellent anti-interference capabilities in complex environments. Furthermore, resonant MEMS sensors are small, lightweight, and compact, making them easy to integrate into miniaturized devices and suitable for a variety of applications. These advantages have led to their widespread application in industrial automation, automotive electronics, medical equipment, environmental monitoring, and other fields, making them a key development area in sensor technology.

[0003] Resonant sensors are widely used in various fields due to their high precision and sensitivity. However, their performance is easily affected by temperature fluctuations, leading to measurement errors. Temperature changes can cause changes in material properties and deformation of the mechanical structure, thereby affecting the stability of the resonant frequency. For example, when the ambient temperature rises, the thermal expansion of the material causes the resonator structure to deform, thereby changing its natural frequency and causing output signal drift. In addition, the mismatch in the thermal expansion coefficient between the packaging material and the sensitive element can also generate thermal stress, further interfering with the sensor's accuracy.

[0004] In order to solve these problems, a variety of compensation methods have been proposed in the prior art. Among them, multi-resonator integration is an effective means. By integrating multiple resonators in the sensor and utilizing their response differences to temperature changes, a differential structure can be designed to offset the frequency drift caused by temperature. For example, Lu Y, et al. Measurement, 2024, 224:113946, etc., a double tuning fork resonator structure is used. The frequency offsets generated by the two under temperature changes offset each other, thereby achieving decoupling of the measured value and temperature. However, this method increases the size of the MEMS device and requires a complex design process to achieve sensitivity matching. Another method is multi-sensor integration. By integrating a temperature sensor and a resonant sensor on the same chip, the temperature change is monitored in real time and the resonant frequency is dynamically adjusted. For example, Xiang C, et al. Micromachines, 2020, 11 (11): 1022, etc., a thermistor is used to work in conjunction with the resonator, and the frequency drift caused by temperature is compensated in real time through a closed-loop feedback system to ensure that the sensor maintains high accuracy within the entire temperature range. However, this method also increases the size and power consumption of the device. At the same time, due to the position differences between multiple devices, thermal hysteresis may occur. There is also an in-situ temperature compensation of the sensor through the amplitude of the resonator, such as the technical invention "A temperature self-compensated resonant pressure sensor control circuit and its implementation method" (CN114646412A), etc., which gives the resonator a constant excitation through the circuit. Since the resonator amplitude changes with temperature, in-situ temperature compensation is achieved by detecting the amplitude of the resonator. This method is simple and easy to implement, but the detection and transmission of the amplitude signal are susceptible to external interference, which affects the stability of the sensor. In addition, there are also methods to eliminate temperature interference directly through temperature control, such as SALVIA JC, et al. Journal of Microelectromechanical Systems, 2010, 19 (1): 192-201, etc., which maintain the operating temperature of the resonator at a constant level by integrating a micro heater. This method greatly increases the system complexity and power consumption, and is only applicable when the external temperature environment is low.

[0005] Micromechanical resonators are the core structure of resonant MEMS sensors. Micromechanical resonators typically have multiple modes, and different modal frequencies have varying sensitivities to changes in environmental parameters. Utilizing the multiple modes of a micromechanical resonator for simultaneous sensing, known as multimodal sensing, effectively decouples the measured quantity from temperature changes, enabling in-situ temperature measurement and compensation. This approach also promises to further reduce device size, lower system complexity and production costs, and improve sensor stability. Summary of the Invention

[0006] In view of this, the present application provides a dual-mode resonant sensor and a closed-loop control method thereof.

[0007] One aspect of the present application provides a dual-mode resonant sensor and a closed-loop control method thereof, comprising: a single resonator, wherein a first differential detection electrode pair, a second differential detection electrode pair and a driving electrode pair are provided on both sides of its resonant beam; the first differential detection electrode pair is symmetrically arranged on both sides of the middle of the resonant beam, for detecting the first-order modal vibration signal of the single resonator; the second differential detection electrode pair is symmetrically arranged at both ends of one side of the resonant beam, for detecting the second-order modal vibration signal of the single resonator; the driving electrode pair is arranged at both ends of the other side of the resonant beam, opposite to the second differential detection electrode pair, and the driving electrode pair is used to apply an AC driving signal to the resonant beam; a closed-loop control circuit, which is connected to the first differential detection electrode pair through a pair of first input ends, is connected to the second differential detection electrode pair through a pair of second input ends, and has an output end connected to the driving electrode pair, for feedback-adjusting the AC driving signal according to the first-order modal vibration signal and / or the second-order modal vibration signal.

[0008] According to an embodiment of the present application, the closed-loop control circuit includes: an adder for adding a first feedback drive signal generated according to the first-order modal vibration signal and a second feedback drive signal generated according to the second-order modal vibration signal when the first-order modal vibration signal and the second-order modal vibration signal are detected simultaneously; the closed-loop control circuit adjusts the AC drive signal based on the sum of the first feedback drive signal and the second feedback drive signal.

[0009] According to an embodiment of the present application, the closed-loop control circuit includes: a first-order modal closed-loop control circuit, including a first transimpedance amplifier sub-circuit, a second transimpedance amplifier sub-circuit, a first differential amplifier sub-circuit, a first phase-shift amplifier sub-circuit and a first control sub-circuit; the first transimpedance amplifier sub-circuit and the second transimpedance amplifier sub-circuit are used to amplify the first-order modal vibration signal detected by the first differential detection electrode pair; the first differential amplifier sub-circuit is used to calculate the first differential signal of the signal amplified by the first transimpedance amplifier sub-circuit and the second transimpedance amplifier sub-circuit; the first phase-shift amplifier sub-circuit is used to adjust the phase of the first differential signal; the first control sub-circuit is used to generate a first feedback drive signal based on the first differential signal after adjusting the phase, so as to realize feedback regulation of the AC drive signal.

[0010] According to an embodiment of the present application, the closed-loop control circuit includes: a second-order modal closed-loop control circuit, including a third transimpedance amplifier sub-circuit, a fourth transimpedance amplifier sub-circuit, a second differential amplifier sub-circuit, a second phase-shift amplifier sub-circuit and a second control sub-circuit; the third transimpedance amplifier sub-circuit and the fourth transimpedance amplifier sub-circuit are used to amplify the second-order modal vibration signal detected by the second differential detection electrode pair; the second differential amplifier sub-circuit is used to calculate the second differential signal of the second-order modal vibration signal detected by the second differential detection electrode pair; the second phase-shift amplifier sub-circuit is used to adjust the phase of the second differential signal; the second control sub-circuit is used to generate a second feedback drive signal based on the second differential signal after adjusting the phase, so as to realize feedback regulation of the AC drive signal.

[0011] According to an embodiment of the present application, the closed-loop control circuit is a closed-loop control circuit based on automatic gain control or a closed-loop control circuit based on a phase-locked loop.

[0012] According to an embodiment of the present application, a feedback driving signal for feedback-adjusting the AC driving signal is applied to one or both electrodes of the driving electrode pair.

[0013] Another aspect of the present application provides a closed-loop control method, which is applied to the dual-mode resonant sensor as described in the first aspect, including: detecting the first-order modal vibration signal of the single resonator based on a first differential detection electrode pair arranged in the middle of the resonant beam of the single resonator, and / or detecting the second-order modal vibration signal of the single resonator based on a second differential detection electrode pair arranged at both ends of one side of the resonant beam; and feedback-adjusting the AC drive signal of the single resonator according to the first-order modal vibration signal and / or the second-order modal vibration signal.

[0014] According to an embodiment of the present application, the feedback adjustment of the AC drive signal of the single resonator based on the first-order modal vibration signal and / or the second-order modal vibration signal includes: when the first-order modal vibration signal and the second-order modal vibration signal are detected simultaneously, adding a first feedback drive signal generated according to the first-order modal vibration signal and a second feedback drive signal generated according to the second-order modal vibration signal; and adjusting the AC drive signal based on the sum of the first feedback drive signal and the second feedback drive signal.

[0015] According to an embodiment of the present application, when the first-order modal vibration signal is detected, the feedback adjustment of the AC drive signal of the single resonator based on the first-order modal vibration signal and / or the second-order modal vibration signal includes: amplifying the first-order modal vibration signal detected by the first differential detection electrode pair and calculating the first differential signal of the first-order modal vibration signal; adjusting the phase of the first differential signal, and generating a first feedback drive signal based on the first differential signal after the phase is adjusted, thereby realizing feedback adjustment of the AC drive signal.

[0016] According to an embodiment of the present application, when the second-order modal vibration signal is detected, the feedback adjustment of the AC drive signal of the single resonator based on the first-order modal vibration signal and / or the second-order modal vibration signal includes: amplifying the second-order modal vibration signal detected by the second differential detection electrode pair and calculating the second differential signal of the amplified second-order modal vibration signal; adjusting the phase of the second differential signal, and generating a second feedback drive signal based on the second differential signal after the phase adjustment, thereby realizing feedback adjustment of the AC drive signal.

[0017] According to an embodiment of the present application, dual-modal closed-loop and synchronous real-time readout of dual-modal frequencies are achieved through dual differential detection based on modal symmetry. Since different modal frequencies have different sensitivities to changes in environmental parameters, the dual-modal sensing implemented in the present application can well decouple the physical quantity to be measured and temperature changes, and realize in-situ temperature measurement and compensation or multi-parameter measurement. Since only one resonator is required, the device size, design complexity, production cost, etc. of the sensor of the present application can be greatly reduced. At the same time, the present application is essentially still dual-frequency sensing, which retains the advantages of frequency output and ensures the stability and reliability of the sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and other objects, features and advantages of the present application will become more apparent through the following description of the embodiments of the present application with reference to the accompanying drawings, in which:

[0019] Figure 1 Schematically shows a schematic diagram of a resonator of a dual-mode resonant sensor according to an embodiment of the present application;

[0020] Figure 2 The following schematically shows a first-order modal closed-loop control subcircuit according to an embodiment of the present application;

[0021] Figure 3 Schematically shows a schematic diagram of a second-order modal closed-loop control subcircuit according to an embodiment of the present application;

[0022] Figure 4 The figure schematically shows a schematic diagram of a dual-mode closed-loop control circuit of a resonator according to an embodiment of the present application. DETAILED DESCRIPTION

[0023] Hereinafter, embodiments of the present application will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present application. In the detailed description below, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present application. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present application.

[0024] The terms used herein are only for describing specific embodiments and are not intended to limit this application. The terms "comprise," "include," etc. used herein indicate the presence of the features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0025] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0026] This application addresses the challenges of existing resonant sensor temperature compensation technology by designing a sensor and related closed-loop circuit. By leveraging the multimodal properties of micromechanical resonators, this approach decouples the measured value from the temperature, enabling multi-parameter measurement through single-resonator multimodal sensing. Because the proposed method requires only a single resonator, the sensor's device size, design complexity, and production cost can be significantly reduced.

[0027] An embodiment of the present application provides a dual-mode resonant sensor comprising a single resonator and a closed-loop control circuit, wherein the single resonator has three pairs of electrodes on both sides.

[0028] like Figure 1 As shown, a first differential detection electrode pair (2-2 and 2-5), a second differential detection electrode pair (2-4 and 2-6) and a driving electrode pair (2-1 and 2-3) are provided on both sides of the resonant beam of the single resonator 1.

[0029] The driving electrode pair (2-1 and 2-3) is provided at both ends of the other side of the resonance beam, opposite to the second differential detection electrode pair, and is used to apply an AC driving signal to the resonance beam.

[0030] The first differential detection electrode pair (2-2 and 2-5) is symmetrically positioned on either side of the middle of the resonant beam. It detects the first-order modal vibration signal of single resonator 1 when the resonator is in its first-order modal vibration state. This differential detection amplifies the resonator's first-order modal vibration signal, improving the signal-to-noise ratio and filtering out common-mode interference signals.

[0031] A second pair of differential detection electrodes (2-4 and 2-6) are symmetrically positioned at either end of one side of the resonant beam. They detect the second-order modal vibration signal of single resonator 1 when the resonator is in its second-order mode. This differential detection amplifies the resonator's second-order modal vibration signal, improving the signal-to-noise ratio and filtering out first-order modal and other common-mode interference.

[0032] A closed-loop control circuit is connected to a first differential detection electrode pair (2-2 and 2-5) via a pair of first input terminals, is connected to a second differential detection electrode pair (2-4 and 2-6) via a pair of second input terminals, and has an output terminal connected to a drive electrode pair, and is used to adjust the AC drive signal based on feedback of the first-order modal vibration signal and / or the second-order modal vibration signal.

[0033] Specifically, the resonator can be operated in a closed-loop stable vibration state through a closed-loop control circuit based on automatic gain control (AGC) or a phase-locked loop. Taking the closed-loop circuit based on automatic gain control (AGC) as an example, the structure of the closed-loop control circuit of the resonator first-order or second-order mode is as follows: Figure 2 or Figure 3 As shown, the system includes a transimpedance amplifier, a differential amplifier, a phase-shift amplifier, and an automatic gain control (AGC) stage. Through differential detection and closed-loop feedback, the resonator can maintain stable vibration in the first or second order mode and read out the frequency in real time.

[0034] like Figure 2 As shown, the closed-loop control circuit includes a first-order modal closed-loop control circuit, which includes a first transimpedance amplifier sub-circuit (corresponding to Figure 2 A transimpedance amplifier link in the middle), the second transimpedance amplifier sub-circuit (corresponding to Figure 2 Another transimpedance amplifier link in the first differential amplifier circuit (corresponding to Figure 2 Differential amplifier link), the first phase-shift amplifier sub-circuit (corresponding to Figure 2 Phase shift amplifier link) and the first control sub-circuit (corresponding to Figure 2 AGC control link). Among them,

[0035] The first transimpedance amplifier sub-circuit and the second transimpedance amplifier sub-circuit are connected to two electrodes of the first differential detection electrode pair (2-2 and 2-5) via their respective first input terminals, and are used to amplify the first-order modal vibration signal detected by the first differential detection electrode pair (2-2 and 2-5). The first differential amplifier sub-circuit is used to calculate a first differential signal between the signals amplified by the first and second transimpedance amplifier sub-circuits; the first phase-shift amplifier sub-circuit is used to adjust the phase of the first differential signal; and the first control sub-circuit is used to generate a first feedback drive signal based on the phase-adjusted first differential signal, and to perform feedback regulation on the AC drive signal based on the first feedback drive signal.

[0036] like Figure 3 As shown, the closed-loop control circuit includes a second-order modal closed-loop control circuit, which includes a third transimpedance amplifier sub-circuit (corresponding to Figure 3 A transimpedance amplifier link in the middle), the fourth transimpedance amplifier sub-circuit (corresponding to Figure 3 Another transimpedance amplifier link in the second differential amplifier circuit (corresponding to Figure 3 Differential amplifier link), the second phase-shift amplifier sub-circuit (corresponding to Figure 3 Phase shift amplifier link) and the second control sub-circuit (corresponding to Figure 3 AGC control link).

[0037] The third transimpedance amplifier sub-circuit and the fourth transimpedance amplifier sub-circuit are used to amplify the second-order modal vibration signal detected by the second differential detection electrode pair (2-4 and 2-6); the second differential amplifier sub-circuit is used to calculate the second differential signal of the second-order modal vibration signal detected by the second differential detection electrode pair (2-4 and 2-6); the second phase-shift amplifier sub-circuit is used to adjust the phase of the second differential signal; the second control sub-circuit is used to generate a second feedback drive signal based on the second differential signal after the phase is adjusted, and to perform feedback adjustment on the AC drive signal based on the second feedback drive signal.

[0038] Based on the above closed-loop structure, the closed-loop control circuit structure of the dual-mode resonant sensor proposed in this application is as follows: Figure 4 As shown. Due to the symmetric and antisymmetric characteristics of the first and second-order modes of the resonator, the second-order modal vibration signal of the resonator is filtered out as a common-mode signal through differential detection of detection electrodes 2-2 and 2-5, retaining only the first-order modal vibration signal of the resonator, ensuring a stable closed-loop and real-time frequency readout of the first-order mode. Through differential detection of detection electrodes 2-4 and 2-6, the first-order modal vibration signal of the resonator is filtered out, and the second-order modal vibration signal is differentially amplified, improving the signal-to-noise ratio of the second-order modal vibration signal and ensuring a stable closed-loop and frequency readout of the second-order mode.

[0039] like Figure 4As shown, when simultaneously detecting a first-order modal vibration signal and a second-order modal vibration signal, the closed-loop control circuit includes an adder. The adder is configured to add a first feedback drive signal generated based on the first-order modal vibration signal and a second feedback drive signal generated based on the second-order modal vibration signal. The closed-loop control circuit adjusts the AC drive signal based on the sum of the first and second feedback drive signals. The two closed-loop feedback drive signals are added together by the adder and then applied to the drive electrode 2-1 to maintain the stability of the dual-mode closed-loop vibration.

[0040] Through the proposed dual-mode resonant sensor and its closed-loop system, the first-order modal frequency and the second-order modal frequency of the resonator can be read out synchronously in real time, realizing dual-mode sensing and multi-parameter decoupled measurement.

[0041] In the embodiments of the present application, when multiple modes of the resonator are excited simultaneously, the vibration signal detected by a single detection electrode is superimposed with multiple modal vibration signals and their high-order components, requiring complex signal processing methods to decouple the modal vibration signals. However, the differential detection method based on modal symmetry proposed in the embodiments of the present application can easily decouple the dual-modal vibration signals, ensuring the single, pure, and stable signals in each modal closed-loop control circuit.

[0042] In the embodiment of the present application, the two closed-loop feedback driving signals can be added together by an adder and then applied to one driving electrode, or can be applied separately to two driving electrodes.

[0043] In the embodiments of the present application, the proposed dual-mode resonant sensor and its closed-loop control method are not limited to the first-order and second-order modes of the resonator, but can also achieve simultaneous closed-loop and sensing of the second-order and third-order modes.

[0044] The closed-loop control of a single mode may be a closed-loop control based on automatic gain control (AGC) or a closed-loop control circuit based on a phase-locked loop.

[0045] The dual-mode resonant sensor provided in the embodiments of the present application has a core sensitive structure consisting of a single resonator 1 with three pairs of electrodes on either side. Due to the symmetric and antisymmetric nature of the resonator's modes, dual differential detection using electrodes 2-2 and 2-5, and 2-4 and 2-6, easily decouples the dual-mode vibration signal, ensuring a stable closed-loop dual-mode state and real-time frequency readout.

[0046] According to Figures 1 to 4 For the dual-mode resonant sensor shown, the present application also provides a closed-loop control method, including S1~S2.

[0047] S1, detecting the first-order modal vibration signal of the single resonator 1 based on the first differential detection electrode pair (2-2 and 2-5) arranged in the middle of the resonant beam of the single resonator 1, and / or detecting the second-order modal vibration signal of the single resonator 1 based on the second differential detection electrode pair (2-4 and 2-6) arranged at both ends of one side of the resonant beam.

[0048] S2, adjusting the AC driving signal of the single resonator 1 according to the first-order modal vibration signal and / or the second-order modal vibration signal feedback.

[0049] When the dual-mode resonant sensor is used to detect its first-order modal vibration signal, S2 includes S201 and S202.

[0050] S201 , amplifying a first-order modal vibration signal detected by a first differential detection electrode pair ( 2 - 2 and 2 - 5 ) and calculating a first differential signal of the first-order modal vibration signal.

[0051] S202 : Adjust the phase of the first differential signal, generate a first feedback drive signal based on the first differential signal after the phase adjustment, and perform feedback adjustment on the AC drive signal based on the first feedback drive signal.

[0052] When the dual-mode resonant sensor is used to detect its second-order modal vibration signal, S2 includes S203-S204.

[0053] S203 , amplifying the second-order modal vibration signal detected by the second differential detection electrode pair ( 2 - 4 and 2 - 6 ) and calculating a second differential signal of the amplified second-order modal vibration signal.

[0054] S204 , adjusting the phase of the second differential signal, generating a second feedback drive signal based on the second differential signal after the phase adjustment, and performing feedback adjustment on the AC drive signal based on the second feedback drive signal.

[0055] When the dual-mode resonant sensor detects the first-order modal vibration signal and the second-order modal vibration signal simultaneously, S2 includes S205 to S206.

[0056] S205 , adding a first feedback driving signal generated according to the first-order modal vibration signal and a second feedback driving signal generated according to the second-order modal vibration signal.

[0057] S206 , adjusting the AC driving signal based on the sum of the first feedback driving signal and the second feedback driving signal.

[0058] This method can easily decouple the dual-modal vibration signal through dual differential detection of detection electrodes 2-2 and 2-5, 2-4 and 2-6, ensuring a stable closed loop of the dual mode and real-time frequency readout.

[0059] The dual-mode resonant sensor and closed-loop control method provided in the embodiments of the present application implement dual-mode sensing with a single resonator. Through dual differential detection based on modal symmetry, dual-mode closed-loop control and simultaneous real-time readout of dual-mode frequencies are achieved. Because different modal frequencies have varying sensitivities to changes in environmental parameters, the dual-mode sensing implemented in the present invention effectively decouples the measured physical quantity from temperature changes, enabling in-situ temperature measurement and compensation or multi-parameter measurement.

[0060] Since only one resonator is required, the device size, design complexity, and production cost of the sensor of the present invention can be greatly reduced. At the same time, the present invention is essentially a dual-frequency sensor, retaining the advantages of frequency output and ensuring the stability and reliability of the sensor.

[0061] In addition, the proposed dual-mode closed-loop circuit has a simple structure and can be completed by simply superimposing two traditional closed-loop circuits. It can be implemented through ordinary analog circuits or digital circuits.

[0062] The embodiments of the present application have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present application. Although each embodiment has been described separately above, this does not mean that the measures in each embodiment cannot be advantageously used in combination. Without departing from the scope of the present application, those skilled in the art may make various substitutions and modifications, and these substitutions and modifications should all fall within the scope of the present application.

Claims

1. A dual-mode resonant sensor, characterized in that: include: A single resonator, wherein a first differential detection electrode pair, a second differential detection electrode pair, and a driving electrode pair are provided on both sides of its resonant beam; The first differential detection electrode pair is symmetrically arranged on both sides of the middle portion of the resonant beam, and is used to detect the first-order modal vibration signal of the single resonator; The second differential detection electrode pair is symmetrically arranged at two ends of one side of the resonant beam, and is used to detect the second-order modal vibration signal of the single resonator; The driving electrode pair is provided at two ends of the other side of the resonant beam, opposite to the second differential detection electrode pair, and the driving electrode pair is used to apply an AC driving signal to the resonant beam; A closed-loop control circuit is connected to the first differential detection electrode pair through a pair of first input terminals, is connected to the second differential detection electrode pair through a pair of second input terminals, and has an output terminal connected to the drive electrode pair, and is used to feedback and adjust the AC drive signal based on the first-order modal vibration signal and / or the second-order modal vibration signal.

2. The dual-mode resonant sensor according to claim 1, wherein: The closed-loop control circuit comprises: an adder for adding a first feedback drive signal generated according to the first-order modal vibration signal and a second feedback drive signal generated according to the second-order modal vibration signal when the first-order modal vibration signal and the second-order modal vibration signal are detected simultaneously; The closed-loop control circuit adjusts the AC drive signal based on a sum of the first feedback drive signal and the second feedback drive signal.

3. The dual-mode resonant sensor according to claim 1, wherein: The closed-loop control circuit comprises: A first-order modal closed-loop control circuit, comprising a first transimpedance amplifier sub-circuit, a second transimpedance amplifier sub-circuit, a first differential amplifier sub-circuit, a first phase-shift amplifier sub-circuit, and a first control sub-circuit; The first transimpedance amplification sub-circuit and the second transimpedance amplification sub-circuit are used to amplify the first-order modal vibration signal detected by the first differential detection electrode pair; The first differential amplifier sub-circuit is used to calculate a first differential signal of the signal amplified by the first transimpedance amplifier sub-circuit and the second transimpedance amplifier sub-circuit; The first phase-shift amplifier sub-circuit is used to adjust the phase of the first differential signal; The first control sub-circuit is configured to generate a first feedback drive signal based on the first differential signal after phase adjustment, and perform feedback regulation on the AC drive signal based on the first feedback drive signal.

4. The dual-mode resonant sensor according to claim 1, wherein: The closed-loop control circuit comprises: A second-order modal closed-loop control circuit, comprising a third transimpedance amplifier sub-circuit, a fourth transimpedance amplifier sub-circuit, a second differential amplifier sub-circuit, a second phase-shift amplifier sub-circuit, and a second control sub-circuit; The third transimpedance amplification sub-circuit and the fourth transimpedance amplification sub-circuit are used to amplify the second-order modal vibration signal detected by the second differential detection electrode pair; The second differential amplifier sub-circuit is used to calculate a second differential signal of the signal amplified by the third transimpedance amplifier sub-circuit and the fourth transimpedance amplifier sub-circuit; The second phase-shift amplifier sub-circuit is used to adjust the phase of the second differential signal; The second control sub-circuit is configured to generate a second feedback drive signal based on the second differential signal after phase adjustment, and perform feedback regulation on the AC drive signal based on the second feedback drive signal.

5. The dual-mode resonant sensor according to claim 1, wherein: The closed-loop control circuit is a closed-loop control circuit based on automatic gain control or a closed-loop control circuit based on a phase-locked loop.

6. The dual-mode resonant sensor according to claim 1, wherein: A feedback driving signal for feedback-regulating the AC driving signal is applied to one or both electrodes of the driving electrode pair.

7. A closed-loop control method, applied to the dual-mode resonant sensor according to any one of claims 1 to 6, characterized in that: include: detecting a first-order modal vibration signal of the single resonator based on a first differential detection electrode pair disposed in the middle of a resonant beam of the single resonator, and / or detecting a second-order modal vibration signal of the single resonator based on a second differential detection electrode pair disposed at both ends of one side of the resonant beam; The AC driving signal of the single resonator is adjusted based on the first-order modal vibration signal and / or the second-order modal vibration signal.

8. The closed-loop control method according to claim 7, characterized in that: The step of feedback-adjusting the AC drive signal of the single resonator according to the first-order modal vibration signal and / or the second-order modal vibration signal comprises: When the first-order modal vibration signal and the second-order modal vibration signal are detected simultaneously, a first feedback drive signal generated according to the first-order modal vibration signal and a second feedback drive signal generated according to the second-order modal vibration signal are added; The AC drive signal is adjusted based on a sum of the first feedback drive signal and the second feedback drive signal.

9. The closed-loop control method according to claim 7, characterized in that: When the first-order modal vibration signal is detected, the feedback-adjusting the AC drive signal of the single resonator according to the first-order modal vibration signal and / or the second-order modal vibration signal includes: amplifying the first-order modal vibration signal detected by the first differential detection electrode pair and calculating a first differential signal of the amplified first-order modal vibration signal; The phase of the first differential signal is adjusted, a first feedback drive signal is generated based on the first differential signal after the phase adjustment, and feedback adjustment is performed on the AC drive signal based on the first feedback drive signal.

10. The closed-loop control method according to claim 7, characterized in that: When the second-order modal vibration signal is detected, the feedback-adjusting the AC drive signal of the single resonator according to the first-order modal vibration signal and / or the second-order modal vibration signal includes: amplifying the second-order modal vibration signal detected by the second differential detection electrode pair and calculating a second differential signal of the amplified second-order modal vibration signal; The phase of the second differential signal is adjusted, a second feedback drive signal is generated based on the second differential signal after the phase adjustment, and feedback adjustment is performed on the AC drive signal based on the second feedback drive signal.

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