A high-sensitivity displacement detection method and displacement sensor

Abstract

This invention discloses a high-sensitivity displacement detection method, comprising the following steps: establishing a vibration displacement model of mode A when a resonator in a displacement sensor couples with mode A and mode B; exciting modes A and B of the resonator and coupling them together to obtain the first frequency of the current mode B; using mode A of the resonator to sense external displacement information, causing a shift in the resonant frequency of mode B, and obtaining the second frequency of the current mode B; obtaining the frequency change of mode B based on the first and second frequencies, and thus obtaining the displacement of mode A. This invention is applied to the field of displacement detection, utilizing the mechanism of modal coupling effect and the influence law of one mode on the vibration response of another, to achieve high-sensitivity detection of the vibration displacement of coupled modes by detecting the frequency shift of the modes. This is of great significance for exploring and developing high-sensitivity micro-displacement detection technology.

Description

Technical Field

[0001] This invention relates to the field of displacement detection technology, specifically a high-sensitivity displacement detection method and displacement sensor. Background Technology

[0002] Displacement detection is an important branch of sensor applications, playing a vital role in scientific research and daily life. With advancements in technology and industrial development, higher demands are being placed on highly sensitive micro-displacement detection technologies. Traditional displacement detection technologies mainly include photoelectric displacement detection, piezoelectric detection, capacitive detection, strain gauge detection, and holographic optical detection, among others.

[0003] Existing displacement sensors, when applied to the detection of minute displacements, can be categorized into contact and non-contact measurement methods based on their operating characteristics. Contact measurement offers high accuracy but can interfere with the movement of the measured component, introducing measurement errors. Furthermore, it is limited by manufacturing precision and is generally only applicable to the detection of minute displacements at relatively large scales. Existing non-contact measurement methods avoid the interference errors introduced by contact measurement and are suitable for minute displacement detection at the micro-nano scale; however, further improvements are still needed in terms of sensitivity and stability. Summary of the Invention

[0004] To address the shortcomings of the existing technologies, this invention provides a high-sensitivity displacement detection method and displacement sensor. Utilizing the mechanism of modal coupling effect and the influence law of one mode on the vibration response of another, it achieves high-sensitivity detection of coupled modal vibration displacement by detecting the frequency shift of the modes. This is of great significance for exploring and developing high-sensitivity micro-displacement detection technology.

[0005] To achieve the above objectives, the present invention provides a high-sensitivity displacement detection method, comprising the following steps:

[0006] Step 1: Establish the vibration displacement model of mode A when the resonator in the displacement sensor couples with mode B, as follows:

[0007]

[0008] In the formula, x A Let m be the displacement of mode A. B ω B γ B F B The equivalent mass, eigenfrequency, damping coefficient, and driving force amplitude of mode B are respectively κ. B Let σ be the third-order stiffness nonlinear coupling coefficient of mode B. B This represents the frequency change of mode B;

[0009] Step 2: Excite mode A and mode B of the resonator and couple mode A and mode B to obtain the resonant frequency of the current mode B, which is defined as the first frequency;

[0010] Step 3: Sensing external displacement information through mode A of the resonator, causing the resonant frequency of mode B to shift, and obtaining the resonant frequency of the current mode B, which is defined as the second frequency;

[0011] Step 4: Obtain the frequency change of mode B based on the first frequency and the second frequency, and obtain the displacement of mode A based on the vibration displacement model of mode A and the frequency change of mode B.

[0012] In one embodiment, step 1, the process of constructing the vibration displacement model is as follows:

[0013] The nonlinear dynamic model for a resonator with two coupled modes that are simultaneously excited is established as follows:

[0014]

[0015] In the formula, x B Let m be the displacement of mode B. A ω A γ A F A The equivalent mass, eigenfrequency, damping coefficient, and driving force amplitude of mode A are respectively κ. A Let α be the third-order stiffness nonlinear coupling coefficient of mode A. A α B Let β be the first-order stiffness nonlinear coupling coefficient of modes A and B. A β B Let ω be the second-order stiffness nonlinear coupling coefficient for modes A and B. dA ω dB Let ω be the angular frequencies of mode A and mode B, and t be time.

[0016] By solving the nonlinear dynamic model using the rotating wave approximation method, the response relationship between mode A and mode B at steady-state response is obtained as follows:

[0017]

[0018] In the formula, σ A Let σ be the frequency change of mode A, where σ B =(ω dB -ω B ) / γ B , σ A =(ω dA -ω A ) / γ A ;

[0019] Taking mode B as the observation object, and under closed-loop control, mode B is brought to a resonant state such that the displacement of mode B satisfies |x B |=F B / m B ω B γ B Substituting this into the response relationship between mode A and mode B, we obtain the vibration displacement model for mode A, which is:

[0020]

[0021] In one embodiment, in step 2, the mode A and mode B of the resonator are excited, and mode A and mode B are coupled, specifically as follows:

[0022] When the resonator is powered on, the first control parameter of mode B is selected, and the resonant frequency of mode B is locked according to the first control parameter. A corresponding first driving signal is generated and applied to the driving electrode of the resonator to excite mode B of the resonator.

[0023] After mode B is excited, the amplitude of the first driving signal is automatically adjusted according to the amplitude of the response signal of mode B in order to maintain the motion amplitude of mode B.

[0024] The second control parameter of mode A is selected, and the resonant frequency of mode A is locked according to the second control parameter. The corresponding second driving signal is generated and applied to the driving electrode of the resonator to excite mode A of the resonator. This causes the frequency of mode B to shift under the action of mode A, thus completing the coupling between mode A and mode B.

[0025] To achieve the above objectives, the present invention also provides a displacement sensor, comprising:

[0026] A resonator includes a resonant structure and a driving electrode, wherein the driving electrode is used to input an external excitation signal, and the resonant structure is used to resonate under the drive of the external excitation signal to generate mode A and mode B;

[0027] The control system is electrically connected to the resonator and is used to select the first control parameter and the second control parameter, and generate the corresponding first drive signal and the second drive signal based on the first control parameter and the second control parameter, and then apply the first drive signal and the second drive signal to the corresponding drive electrode of the resonator.

[0028] The displacement measurement module is electrically connected to the resonator and has the aforementioned vibration displacement model built in. It is used to collect the first and second frequencies of mode B and obtain the displacement of mode A based on the vibration displacement model.

[0029] In one embodiment, the control system includes:

[0030] The first parameter control module is used to set the first control parameters, including the mode B drive amplitude, mode B drive frequency, and mode B drive phase.

[0031] The mode B driving loop is electrically connected to the first parameter control module and the resonator, and is used to generate a first driving signal in response to the first control parameter to realize the control of the resonator mode B.

[0032] The second parameter control module is used to set the second control parameters, including the mode A drive amplitude, mode A drive frequency, and mode A drive phase;

[0033] The mode A driving loop is electrically connected to the second parameter control module and the resonator, and is used to generate a second driving signal in response to the second control parameter to control the mode A of the resonator.

[0034] In one embodiment, the mode B driving loop includes:

[0035] The first phase-locked module is electrically connected to the first parameter control module and is used to generate a first drive signal according to the first control signal and keep the frequency of the first drive signal consistent with the resonant frequency of mode B of the resonator.

[0036] The first amplitude control module is electrically connected to the first phase-locked module and the resonator, and is used to control and maintain the vibration amplitude of mode B of the resonator.

[0037] In one embodiment, the mode A driving loop includes:

[0038] The second phase-locked module is electrically connected to the second parameter control module and is used to generate a second drive signal according to the second control signal, and to keep the frequency of the second drive signal consistent with the resonant frequency of mode A of the resonator.

[0039] The second amplitude control module is electrically connected to the second phase-locked module and the resonator, and is used to control and maintain the vibration amplitude of mode A of the resonator.

[0040] This invention provides a high-sensitivity displacement detection method and displacement sensor. It constructs a vibration displacement model using the mechanism of modal coupling, and utilizes the influence of one mode on the vibration response of another. By detecting the frequency shift of the modes, it achieves high-sensitivity detection of the vibration displacement of coupled modes. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0042] Figure 1 This is a flowchart of the displacement detection method in an embodiment of the present invention;

[0043] Figure 2 This is a schematic diagram of the displacement sensor module in an embodiment of the present invention;

[0044] Figure 3 This is a schematic diagram of the experimental test on the effect of the displacement of mode A on the resonant frequency of mode B in an embodiment of the present invention;

[0045] Figure 4 This is a theoretical schematic diagram illustrating the influence of the displacement of mode A on the resonant frequency of mode B in an embodiment of the present invention.

[0046] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0048] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0049] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0050] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection, an electrical connection, a physical connection, or a wireless communication connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two elements or the interaction between two elements, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0051] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0052] Example 1

[0053] Modal coupling is a typical nonlinear physical effect in resonators, significantly influencing their dynamic response. When modal coupling exists in a resonator, the originally independent intrinsic modes couple together, affecting each other. The response of one mode modulates the response of another. Utilizing this coupling effect, the response information of the coupled modes can be calculated by observing the response of one mode, without affecting the response information of the coupled modes. Therefore, based on the modal coupling effect of resonators, this embodiment proposes a highly sensitive, non-destructive method for detecting minute displacements, referencing... Figure 1 The method specifically includes the following steps:

[0054] Step 1: Establish the vibration displacement model of mode A when the resonator in the displacement sensor couples with mode B. The specific implementation process is as follows:

[0055] When two intrinsic modes of a capacitive micromechanical resonator are simultaneously excited, they are coupled together, and the responses of the two modes are correlated and influence each other. The dynamic equation of each mode contains the motion information of the other mode. At this time, the nonlinear dynamic response model of the two modes of the resonator under external excitation can be expressed as:

[0056]

[0057] In the formula, x A x B These are the displacements of mode A and mode B, respectively, in m. A m B Let ω be the equivalent mass of mode A and mode B, respectively. A ωB The eigenfrequency γ represents the eigenfrequency of mode A and mode B, respectively. A γ B The damping coefficients for modes A and B are α and α, respectively. A α B These are the first-order stiffness nonlinear coupling coefficients for modes A and B, respectively, β A β B κ represents the second-order stiffness nonlinear coupling coefficients of modes A and B, respectively. A κ B F represents the third-order stiffness nonlinear coupling coefficients of modes A and B, respectively. A F B The driving force amplitudes ω for modes A and B respectively. dA ω dB ω and ω are the angular frequencies of mode A and mode B, respectively, and t is time.

[0058] Using the rotating wave approximation method to solve the nonlinear dynamic model, when the system is in steady-state response, the response relationship between mode A and mode B is obtained as follows:

[0059]

[0060] In the formula, σ A σ B Let σ be the frequency change of mode A, where σ is the frequency change of mode A. A =(ω dA -ω A ) / γ A , σ B =(ω dB -ω B ) / γ B ;

[0061] When the sensitive mode (mode B) and the coupled mode (mode A) of the resonator are simultaneously excited, the frequency drift of the operating mode caused by the modal coupling effect can be obtained by numerically solving the response relationship between mode A and mode B. From the response relationship between mode A and mode B, it can be seen that the maximum frequency shift of any mode is closely related to the amplitude of the excitation signal of the other mode. When mode B is taken as the observation object, and mode B is brought to a resonant state under closed-loop control, so that the displacement of mode B satisfies |x B |=F B / m B ω B γ B Substituting this into the response relationship between mode A and mode B, we obtain the vibration displacement model for mode A, which is:

[0062]

[0063] From the above equation, we can see that the square of the vibration displacement of the coupled mode |x A | 2 Frequency variation σ of mode B B There is a negative correlation. Its detection sensitivity can be expressed as:

[0064]

[0065] Therefore, when modes A and B of the resonator operate simultaneously, the frequency shift of mode B can be used to characterize the vibration displacement of mode A, without affecting the normal motion of the coupled modes. Furthermore, its detection sensitivity is related to the structural parameters of the resonator, and high-precision micro-displacement detection with different sensitivity ranges can be achieved by rationally designing the structural parameters according to different application requirements.

[0066] Step 2: Excite modes A and B of the resonator and couple them to obtain the resonant frequency of the current mode B, which is defined as the first frequency. The specific implementation process is as follows:

[0067] After the resonator is powered on, the first control parameter of mode B is selected, and the resonant frequency of mode B is locked according to the first control parameter. A corresponding first driving signal is generated and applied to the driving electrode of the resonator to excite mode B of the resonator. The first control parameter includes the driving amplitude of mode B, the driving frequency of mode B, and the driving phase of mode B.

[0068] After mode B is excited, the amplitude of the first driving signal is automatically adjusted according to the amplitude of the response signal of mode B in order to maintain the motion amplitude of mode B.

[0069] Subsequently, the second control parameter of mode A is selected, and the resonant frequency of mode A is locked according to the second control parameter. A corresponding second driving signal is generated and applied to the driving electrode of the resonator to excite mode A of the resonator. This causes the frequency of mode B to shift under the action of mode A, thus completing the coupling between mode A and mode B. The resonant frequency of mode B at this time is recorded as the first frequency. The second control parameter includes the driving amplitude of mode A, the driving frequency of mode A, and the driving phase of mode A.

[0070] Step 3: The resonator's mode A is used to sense external displacement information. When changes in external displacement information cause changes in the vibration displacement of mode A, the amplitude of the second driving signal is automatically adjusted according to the amplitude of the response signal of mode A to maintain the motion amplitude of mode A. As the vibration displacement of mode A changes, the resonant frequency of mode B shifts, and the current resonant frequency of mode B is obtained and defined as the second frequency.

[0071] Step 4: The frequency change σ of mode B is obtained by subtracting the first frequency from the second frequency.B Based on the vibration displacement model of mode A and the frequency change of mode B, the vibration displacement of mode A is obtained, that is, the frequency change σ of mode B. B Substituting the values ​​into the vibration displacement model, we obtain the displacement detection values.

[0072] Example 2

[0073] Based on the displacement detection method in Embodiment 1, this embodiment discloses a displacement sensor, which mainly consists of a resonator, a control system, and a displacement measurement module.

[0074] The resonator includes a resonant structure and several driving electrodes. The number of driving motors corresponds one-to-one with the total number of modes possessed by the resonator. The resonant structure is used to resonate under the drive of an external excitation signal, generating a sensitive mode (i.e., mode B in Example 1) and a pump mode (i.e., mode A in Example 1) for energy exchange and signal processing. Mode B is one of the intrinsic modes of the resonant structure, resonating under the excitation of the first driving signal and outputting a response signal. Its resonant frequency is related to the vibration amplitude of mode A. Mode A is also one of the intrinsic modes of the resonant structure, resonating under the excitation of the second driving signal and outputting a response signal. Its vibration amplitude affects the offset range of the resonant frequency of mode B. The driving electrodes are used to connect the driving signals transmitted by the control system, such as the first driving signal and the second driving signal in Example 1, thereby exciting the resonant structure to generate coupled modes of the resonant structure, such as mode A and mode B in Example 1.

[0075] The control system is electrically connected to the resonator and is used to control, process and characterize the motion characteristics of the resonant structure. This includes selecting a first control parameter and a second control parameter, generating a corresponding first drive signal and a second drive signal based on the first control parameter and the second control parameter, applying the first drive signal and the second drive signal to the corresponding drive electrode of the resonator, and displaying the response information of mode A and mode B.

[0076] Specifically, the control system includes a first parameter control module, a mode B drive loop, a second parameter control module, a mode A drive loop, and a response output module.

[0077] The first parameter control module is used to set the first control parameters, including the mode B drive amplitude, mode B drive frequency, and mode B drive phase, and then transmits the first control parameters to the mode B drive loop.

[0078] The mode B driving loop responds to the first control parameters transmitted by the first parameter control module, converting the first control parameters into corresponding excitation signals and transmitting them to the corresponding driving electrodes on the resonator. Specifically, the mode B driving loop mainly includes a first phase-locked loop (PLL) module and a first amplitude control module. The first PLL module generates a first driving signal with a frequency close to the resonant frequency of mode B based on the first control parameters, and maintains the frequency of the first driving signal consistent with the resonant frequency of mode B. The first amplitude control module controls and maintains the vibration amplitude of mode B.

[0079] The second parameter control module is used to set the second control parameters, including the mode A drive amplitude, mode A drive frequency, and mode A drive phase. These second control parameters are then transmitted to the mode A drive loop.

[0080] The Mode A drive loop responds to the second control parameters transmitted by the second parameter control module, converting the second control parameters into corresponding excitation signals and transmitting them to the corresponding drive electrodes on the resonator. Specifically, the Mode A drive loop mainly includes a second phase-locked loop (PLL) module and a second amplitude control module. The second PLL module generates a second drive signal with a frequency close to the resonant frequency of Mode A based on the second control parameters, and maintains the frequency of the second drive signal consistent with the resonant frequency of Mode A. The second amplitude control module controls and maintains the vibration amplitude of Mode A.

[0081] The response output module is electrically connected to the resonator and is used to display the output signal of the displacement sensor, including but not limited to the resonant amplitude, resonant phase, and resonant frequency of the resonator's working mode, as well as the resonant amplitude, resonant phase, and resonant frequency of the resonator's pump mode.

[0082] The displacement measurement module is electrically connected to the resonator and has the vibration displacement model of Embodiment 1 built in. It is used to collect the first and second frequencies of mode B and obtain the displacement of mode A based on the vibration displacement model.

[0083] Figure 3 and Figure 4 These are experimental test diagrams illustrating the effect of mode A displacement on the resonant frequency of mode B, and theoretical diagrams illustrating the effect of mode A displacement on the resonant frequency of mode B. From... Figure 3-4 As can be seen, the implementation examples match the theoretical analysis. With the change in the displacement of mode A, the resonant frequency of mode B shifts accordingly. The shift in the resonant frequency of mode B is proportional to the square of the change in the displacement of mode A. As the displacement of mode A increases, the degree of shift in the resonant frequency of mode B increases, and the sensitivity also increases. By observing the shift in the resonant frequency of mode B, the change in the displacement of mode A can be obtained, demonstrating the potential for highly sensitive displacement detection applications.

[0084] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A high-sensitivity displacement detection method, characterized in that, Includes the following steps: Step 1: Establish the vibration displacement model of mode A when the resonator in the displacement sensor couples with mode B, as follows: In the formula, x A Let m be the displacement of mode A. B ω B γ B F B The equivalent mass, eigenfrequency, damping coefficient, and driving force amplitude of mode B are respectively κ. B Let σ be the third-order stiffness nonlinear coupling coefficient of mode B. B This represents the frequency change of mode B; Step 2: Excite mode A and mode B of the resonator and couple mode A and mode B to obtain the resonant frequency of the current mode B, which is defined as the first frequency; Step 3: Sensing external displacement information through mode A of the resonator, causing the resonant frequency of mode B to shift, and obtaining the resonant frequency of the current mode B, which is defined as the second frequency; Step 4: Obtain the frequency change of mode B based on the first frequency and the second frequency, and obtain the displacement of mode A based on the vibration displacement model of mode A and the frequency change of mode B.

2. The high-sensitivity displacement detection method according to claim 1, characterized in that, In step 1, the specific process of constructing the vibration displacement model is as follows: The nonlinear dynamic model for a resonator with two coupled modes that are simultaneously excited is established as follows: In the formula, x B Let m be the displacement of mode B. A ω A γ A F A The equivalent mass, eigenfrequency, damping coefficient, and driving force amplitude of mode A are respectively κ. A Let α be the third-order stiffness nonlinear coupling coefficient of mode A. A α B Let β be the first-order stiffness nonlinear coupling coefficient of modes A and B. A β B Let ω be the second-order stiffness nonlinear coupling coefficient for modes A and B. dA ω dB Let ω be the angular frequencies of mode A and mode B, and t be time. By solving the nonlinear dynamic model using the rotating wave approximation method, the response relationship between mode A and mode B at steady-state response is obtained as follows: In the formula, σ A Let σ be the frequency change of mode A, where σ B =(ω dB -ω B ) / γ B , σ A =(ω dA -ω A ) / γ A ; Taking mode B as the observation object, and under closed-loop control, mode B is brought to a resonant state such that the displacement of mode B satisfies |x B |=F B / m B ω B γ B Substituting this into the response relationship between mode A and mode B, we obtain the vibration displacement model for mode A, which is:

3. The high-sensitivity displacement detection method according to claim 1 or 2, characterized in that, In step 2, the mode A and mode B of the resonator are excited, and mode A and mode B are coupled, specifically as follows: When the resonator is powered on, the first control parameter of mode B is selected, and the resonant frequency of mode B is locked according to the first control parameter. A corresponding first driving signal is generated and applied to the driving electrode of the resonator to excite mode B of the resonator. After mode B is excited, the amplitude of the first driving signal is automatically adjusted according to the amplitude of the response signal of mode B in order to maintain the motion amplitude of mode B. The second control parameter of mode A is selected, and the resonant frequency of mode A is locked according to the second control parameter. The corresponding second driving signal is generated and applied to the driving electrode of the resonator to excite mode A of the resonator. This causes the frequency of mode B to shift under the action of mode A, thus completing the coupling between mode A and mode B.

4. A displacement sensor, characterized in that, include: A resonator includes a resonant structure and a driving electrode, wherein the driving electrode is used to input an external excitation signal, and the resonant structure is used to resonate under the drive of the external excitation signal to generate mode A and mode B; The control system is electrically connected to the resonator and is used to select the first control parameter and the second control parameter, and generate the corresponding first drive signal and the second drive signal based on the first control parameter and the second control parameter, and then apply the first drive signal and the second drive signal to the corresponding drive electrode of the resonator. The displacement measurement module is electrically connected to the resonator and has a built-in vibration displacement model as described in claim 1, 2 or 3, for acquiring the first frequency and the second frequency of mode B, and obtaining the displacement of mode A based on the vibration displacement model.

5. The displacement sensor according to claim 4, characterized in that, The control system includes: The first parameter control module is used to set the first control parameters, including the mode B drive amplitude, mode B drive frequency, and mode B drive phase. The mode B driving loop is electrically connected to the first parameter control module and the resonator, and is used to generate a first driving signal in response to the first control parameter to realize the control of the resonator mode B. The second parameter control module is used to set the second control parameters, including the mode A drive amplitude, mode A drive frequency, and mode A drive phase; The mode A driving loop is electrically connected to the second parameter control module and the resonator, and is used to generate a second driving signal in response to the second control parameter to control the mode A of the resonator.

6. The displacement sensor according to claim 5, characterized in that, The mode B driving loop includes: The first phase-locked module is electrically connected to the first parameter control module and is used to generate a first drive signal according to the first control signal and keep the frequency of the first drive signal consistent with the resonant frequency of mode B of the resonator. The first amplitude control module is electrically connected to the first phase-locked module and the resonator, and is used to control and maintain the vibration amplitude of mode B of the resonator.

7. The displacement sensor according to claim 5, characterized in that, The mode A driving loop includes: The second phase-locked module is electrically connected to the second parameter control module and is used to generate a second drive signal according to the second control signal, and to keep the frequency of the second drive signal consistent with the resonant frequency of mode A of the resonator. The second amplitude control module is electrically connected to the second phase-locked module and the resonator, and is used to control and maintain the vibration amplitude of mode A of the resonator.

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