A differential acceleration sensor based on modal localization effect

Abstract

The invention discloses a differential acceleration sensor based on modal localization effect, comprising: the differential acceleration sensor is of a central symmetrical structure, comprising: a mass block, a first coupler and a second coupler are symmetrically arranged on both sides of the mass block; the first coupler and the second coupler have the same structure; the first coupler comprises a first resonator and a second resonator which are symmetrically arranged; the first resonator and the second resonator have the same structure; the first resonator is composed of a first tuning fork beam; the first tuning fork beam adopts an I-shaped beam; the second resonator is composed of a second tuning fork beam; the first tuning fork beam is placed on the upper right side of the mass block, and the two ends of the first tuning fork beam are respectively fixed by a first fixed end, a first micro lever and a second micro lever; the second tuning fork beam is located on the lower side of the first tuning fork beam. The invention can realize online adjustment of sensor sensitivity, resolution and detection range, and has the advantages of high sensitivity, strong robustness and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of micro-electromechanical systems, and in particular to a differential acceleration sensor based on modal localization effect, belonging to the field of sensors. Background Art

[0002] In recent years, high-precision acceleration sensors have been used more and more widely in application scenarios such as shock wave detection, microgravity platforms, and high-precision inertial navigation. Their types include piezoresistive, capacitive, and resonant types.

[0003] Among them, MEMS resonant accelerometers have attracted more and more attention due to their small size and easy integration. The sensitive mechanism of MEMS resonant accelerometers is based on the change of the axial force of the resonator caused by the inertial force of the mass block, and the change of the resonator amplitude is detected through differential output, and finally the magnitude and direction of acceleration are obtained.

[0004] In order to improve the sensitivity of the accelerometer, Wang Shudong et al. mentioned in "A MEMS resonant accelerometer for low-frequency vibration detection" (Sensors and Actuators A: Physical, 2018, 283 151-158) that by evaluating the static characteristics and complex dynamic characteristics of the resonant accelerometer, compared with the charge accelerometer, the accelerometer is more suitable for low-frequency and low-acceleration vibration measurement, but the accelerometer will be affected by environmental changes. Wei Xueyong et al. proposed in "MEMS based ultra-high order frequency multiplication utilizing superharmonic synchronization effect [J]. " (Sensors and Actuators A: Physical, 2021, 332: 113152.) that the silicon micro-resonant accelerometer uses the synchronization effect to improve the performance of the resonant accelerometer, but there is a problem of frequency tuning degradation in the coupling structure of the synchronous enhanced accelerometer.

[0005] In summary, the resonant accelerometer based on frequency shift output is susceptible to interference from the external environment, and a solution to the problem needs to be found from a mechanism perspective. Accelerometers using the synchronization effect need to separate the dependency between coupling strength and frequency tuning through structural design and nonlinear control to overcome problems such as sensitivity degradation. Summary of the invention

[0006] In order to solve the problem of low sensitivity of the sensor for breakthrough frequency detection, the sensitivity and robustness of the resonant acceleration sensor are improved by modifying and designing the resonant acceleration sensor. The present invention provides a differential acceleration sensor based on the modal localization effect. The following is the technical solution adopted by the present invention:

[0007] A structural schematic diagram of a differential acceleration sensor based on modal localization effect, the differential acceleration sensor is a centrally symmetrical structure, comprising:

[0008] Mass block,

[0009] A first coupler and a second coupler are symmetrically arranged on both sides of the mass block; the first coupler and the second coupler have the same structure;

[0010] The first coupler comprises the first resonator and the second resonator which are symmetrically arranged; the first resonator and the second resonator have the same structure;

[0011] The first resonator is composed of a first tuning fork beam; the first tuning fork beam is an I-shaped beam; the second resonator is composed of a second tuning fork beam;

[0012] The first tuning fork beam is placed on the upper right side of the mass block.

[0013] Two ends of the first tuning fork beam are fixed by a first fixed end and the first micro-lever and the second micro-lever respectively;

[0014] The second tuning fork beam is located at the lower side of the first tuning fork beam,

[0015] The second tuning fork beam is placed on the lower right side of the mass block;

[0016] Two ends of the second tuning fork beam are fixed by a second fixed end and a third fixed end respectively;

[0017] The upper side and the lower side of the mass block are connected to the first anchor point, the second anchor point, the third anchor point, and the fourth anchor point respectively;

[0018] The upper side of the mass block is connected to the first anchor point and the second anchor point through the first support beam and the second support beam, and the lower side is connected to the third anchor point and the fourth anchor point through the third support beam and the fourth support beam;

[0019] The second anchor point is connected to the first fixed end;

[0020] The third anchor point is connected to the second fixed end and the third fixed end;

[0021] The mass block and the first tuning fork beam form a lever structure, which can amplify the inertial force of the mass block; wherein, the first tuning fork beam and the second tuning fork beam are electrostatically coupled, and a coupling power supply outputs a coupling voltage which is loaded on a first fixed end connected to the first tuning fork beam, so as to adjust the electrostatic coupling strength between the first tuning fork beam and the second tuning fork beam;

[0022] The first tuning fork beam adjusts the driving force through a first fixed excitation electrode; the second tuning fork beam adjusts the driving force through a second fixed excitation electrode;

[0023] The first tuning fork beam and the second tuning fork beam detect amplitude and frequency through the first detection electrode and the second detection electrode respectively.

[0024] Further, the width of the second tuning fork beam is equal to the width of the first tuning fork beam.

[0025] Further, the length of the first fixed excitation electrode is equal to the length of the second fixed excitation electrode, and the width of the first fixed excitation electrode is equal to the width of the second fixed excitation electrode.

[0026] Further, the length of the first detection electrode is equal to the length of the second detection electrode, and the width of the first detection electrode is equal to the width of the second detection electrode.

[0027] Furthermore, the length of the first fixed excitation electrode is equal to the tuning fork length of the first tuning fork beam, and the width of the first fixed excitation electrode is equal to the width of the first tuning fork beam; the length of the second fixed excitation electrode is equal to the length of the second tuning fork beam, and the width of the second fixed excitation electrode is equal to the width of the second tuning fork beam.

[0028] Further, the gap between the first fixed excitation electrode and the first tuning fork beam is equal to the gap between the second fixed excitation electrode and the second tuning fork beam, which is equal to the distance between the second tuning fork beam and the first tuning fork beam.

[0029] Furthermore, the voltage source of the first fixed excitation electrode is driven by direct current, and the excitation voltage of the second fixed excitation electrode is driven by both direct current voltage and alternating current voltage.

[0030] Furthermore, the lengths of the first tuning fork beam and the second tuning fork beam are variable and equal.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] 1. The present invention has the characteristic of easy adjustment of coupling strength, and the coupling strength between the clamped beams can be changed only by voltage adjustment;

[0033] 2. The present invention adopts a differential method to improve the sensitivity of detection, and adopts a lever structure to connect with the resonator, thereby greatly amplifying the inertial force of the mass block;

[0034] 3. The feasibility of the proposed structure is verified through implementation examples. The sensitivity is improved by more than 3 orders of magnitude compared with the frequency shift output with amplitude ratio as the output sensitivity.

[0035] In summary, the present invention provides a differential acceleration sensor based on modal localization effect, which has higher sensitivity than frequency detection sensors. In the process of detecting acceleration, the electrostatic coupling strength between the resonators is changed by adjusting the coupling voltage. The left and right sides of the mass block are respectively connected to the resonator. Under the action of inertial force, when the mass block moves axially, the force amplified by the micro-lever structure acts on the resonator, causing the amplitude of the resonator to change. The magnitude of acceleration is obtained by calculating the resonator amplitude ratio of the differential output. The first tuning fork beam, a component of the first resonator, and the second tuning fork beam, a component of the second resonator, are driven by the first fixed excitation electrode and the second fixed excitation electrode respectively. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0037] Figure 1 Schematic diagram of the structure of a differential acceleration sensor based on modal localization effect in an embodiment of the present invention;

[0038] Figure 2 This is an amplitude-frequency characteristic diagram in a balanced state in an embodiment of the present invention;

[0039] Figure 3 is a graph showing the change of the amplitude-frequency characteristic under 1g acceleration disturbance in an embodiment of the present invention;

[0040] Figure 4 (a) is a sensitivity diagram of the relative amplitude ratio change output mode for the out-of-phase mode when the coupling voltage is 70V in an embodiment of the present invention;

[0041] Figure 4 (b) is a sensitivity diagram of the relative amplitude ratio change output mode for the in-phase mode when the coupling voltage is 70V in the embodiment of the present invention.

[0042] Figure 5(a) is a sensitivity diagram of the relative frequency change output mode for the out-of-phase mode when the coupling voltage is 70V in an embodiment of the present invention;

[0043] Figure 5 (b) is a sensitivity diagram of the relative frequency change output mode for the in-phase mode when the coupling voltage is 70V in an embodiment of the present invention;

[0044] Figure markings: 1-1, first anchor point, 1-2, second anchor point, 1-3, third anchor point, 1-4, fourth anchor point; 1-5, first support beam, 1-6, second support beam, 1-7, third support beam, 1-8, fourth support beam; 1-9, mass block; 3-1, first tuning fork beam; 2-1, second tuning fork beam; 3-4, first fixed end; 2-4, second fixed end, 2-5, third fixed end, 3-2, first fixed excitation electrode; 2-2, second fixed excitation electrode; 3-3, first detection electrode; 2-3, second detection electrode; 4-1, first micro-lever structure, 4-2, second micro-lever structure; 5-4, coupling power supply; 4-3, first excitation power supply; 4-4, second excitation power supply. DETAILED DESCRIPTION

[0045] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0046] Since the modal localization phenomenon was applied to resonant sensors, it has been widely used in many fields. By detecting the magnitude of external acceleration by detecting the amplitude ratio of the resonator response, its sensitivity has been improved by at least one level compared to frequency detection sensors. Changes in the external environment will cause changes in the characteristic state and amplitude of the sensor, so it is necessary to improve the acceleration sensor.

[0047] like Figure 1 As shown, the present invention provides a structural schematic diagram of a differential acceleration sensor based on modal localization effect, the differential acceleration sensor is a centrosymmetric structure, the acceleration sensor is a centrosymmetric structure, the following content is the right side feature of the mass block, the left side feature of the mass block is the same as the right side feature. The acceleration sensor includes:

[0048] Mass block 1-9, the mass block is made of silicon material and is rectangular, and its function is: lateral movement. The mass block will move laterally under the action of inertia. Due to the movement, the mass block will exert a strong effect on the tuning fork beams connected to the left and right sides of the mass block through the micro-lever structure. At this time, the tuning fork beams on both sides will be subjected to tension and pressure. Due to the different forces, the amplitude of the tuning fork beam when deformed under the action of the electrode is inconsistent, which reflects the characteristic of difference.

[0049] A first coupler and a second coupler are symmetrically arranged on both sides of the mass block 1-9; the first coupler and the second coupler have the same structure;

[0050] The first coupler includes the first resonator and the second resonator which are symmetrically arranged;

[0051] The first resonator is composed of a first tuning fork beam 3-1; the first tuning fork beam 3-1 adopts an I-shaped beam; the tuning fork beam connected to the micro-lever, under the dual action of the lever force and the coupling force, the amplitude of its deformation will change according to the different acceleration sizes when the mass block moves, which can be obtained by comparing the relative amplitude ratio change with the relative phase-frequency ratio change. The acceleration obtained by the relative amplitude ratio has higher accuracy.

[0052] The second resonator is composed of a second tuning fork beam 2-1;

[0053] The lengths of the first tuning fork beam 3 - 1 and the second tuning fork beam 2 - 1 are variable and equal;

[0054] The first tuning fork beam 3-1 is placed on the upper right side of the mass block 1-9.

[0055] The first tuning fork beam 3-1 has its two ends fixed by the first fixed end 3-4 and the first micro-lever 4-1 and the second micro-lever 4-2 respectively;

[0056] The second tuning fork beam 2-1 is located at the lower side of the first tuning fork beam 3-1.

[0057] The second tuning fork beam 2-1 is placed on the lower right side of the mass block 1-9;

[0058] The two ends of the second tuning fork beam 2-1 are fixed by a second fixed end 2-4 and a third fixed end 2-5 respectively;

[0059] The upper and lower sides of the mass block 1-9 are respectively connected to the first anchor point 1-1, the second anchor point 1-2, the third anchor point 1-3, and the fourth anchor point 1-4; the function of the first anchor point 1-1, the second anchor point 1-2, the third anchor point 1-3, and the fourth anchor point 1-4 is to connect with the mass block through support beams 1-5, 1-6, 1-7, and 1-8, and fix the mass block in the vertical direction.

[0060] The upper side of the mass block 1-9 is connected to the first anchor point 1-1 and the second anchor point 1-2 through the first support beam 1-5 and the second support beam 1-6, and the lower side is connected to the third anchor point 1-3 and the fourth anchor point 1-4 through the third support beam 1-7 and the fourth support beam 1-8;

[0061] The second anchor point 1-2 is connected to the first fixed end 3-4;

[0062] The third anchor point 1-3 is connected to the second fixed end 2-4 and the third fixed end 2-5;

[0063] The mass block 1-9 and the first tuning fork beam 3-1 amplify the inertial force of the mass block 1-9 and the force exerted on the first tuning fork beam 3-1 through a lever structure;

[0064] The first tuning fork beam 3-1 and the second tuning fork beam 2-1 are electrostatically coupled, and the coupling power supply 5-4 outputs a coupling voltage which is loaded on the first fixed end 3-4 connected to the first tuning fork beam 3-1, so as to adjust the electrostatic coupling strength between the first tuning fork beam 3-1 and the second tuning fork beam 2-1;

[0065] The first tuning fork beam 3-1 adjusts the driving force through the first fixed excitation electrode 3-2; the second tuning fork beam 2-1 adjusts the driving force through the second fixed excitation electrode 2-2;

[0066] The first tuning fork beam 3-1 and the second tuning fork beam 2-1 detect the amplitude and frequency through the first detection electrode 3-3 and the second detection electrode 2-3 respectively;

[0067] The length of the first detection electrode 3 - 3 is equal to the length of the second detection electrode 2 - 3 , and the width of the first detection electrode 3 - 3 is equal to the width of the second detection electrode 2 - 3 .

[0068] The length of the second tuning fork beam 2-1 is equal to the length of the first tuning fork beam 3-1.

[0069] The width of the second tuning fork beam 2 - 1 is equal to the width of the first tuning fork beam 3 - 1 .

[0070] The length of the first fixed excitation electrode 3 - 2 is equal to the length of the second fixed excitation electrode 2 - 2 , and the width of the first fixed excitation electrode 3 - 2 is equal to the width of the second fixed excitation electrode 2 - 2 .

[0071] The length of the first fixed excitation electrode 3 - 2 is equal to the length of the first tuning fork beam 3 - 1 , and the width of the first fixed excitation electrode 3 - 2 is equal to the width of the first tuning fork beam 3 - 1 .

[0072] The length of the second fixed excitation electrode 2 - 2 is equal to the length of the second tuning fork beam 2 - 1 , and the width of the second fixed excitation electrode 2 - 2 is equal to the width of the second tuning fork beam 2 - 1 .

[0073] The gap between the first fixed excitation electrode 3-2 and the first tuning fork beam 3-1 is equal to the gap between the second fixed excitation electrode 2-2 and the second tuning fork beam 2-1, and equal to the distance between the second tuning fork beam 2-1 and the first tuning fork beam 3-1.

[0074] The first fixed excitation electrode 3 - 2 and the second fixed excitation electrode 2 - 2 are completely fixed and fixed to the chip.

[0075] The voltage source of the first fixed excitation electrode 3-2 is driven by direct current.

[0076] The voltage source of the second fixed excitation electrode 2 - 2 is driven by both alternating current and direct current.

[0077] The first excitation power supply 4-3 located at the micro-lever fulcrum on the upper right side of the mass block 1-9 supplies power to the first fixed excitation electrode 3-2; the second excitation power supply 4-4 located at the micro-lever fulcrum on the lower right side of the mass block 1-9 supplies power to the second fixed excitation electrode 2-2.

[0078] The present invention provides a differential acceleration sensor based on the modal localization effect, which realizes online adjustment of the sensor sensitivity, detection range and resolution by adjusting the coupling voltage to change the electrostatic coupling strength. The first tuning fork beam and the second tuning fork beam are driven by the first fixed excitation electrode and the second fixed excitation electrode respectively. When the mass block moves under the action of external acceleration, the axial force of the two resonators is changed by the lever, so that the amplitude changes. The magnitude of the acceleration can be obtained by calculating the amplitude ratio of the two resonators through differential output. Compared with the traditional frequency-shift output method, the amplitude ratio output has better ability to resist external environmental interference, better robustness and higher sensitivity.

[0079] Example 1

[0080] A differential acceleration sensor based on modal localization effect provided by the present invention is described below with a specific example.

[0081] like Figure 1The structure diagram of a differential acceleration sensor based on the modal localization effect in an embodiment of the present invention is shown, in which a mass block is connected to an anchor point through support beams on the upper and lower sides, and the left and right sides are respectively connected to the resonator. Under the action of external acceleration, the mass block will undergo axial movement, thereby changing the axial stress of the resonator and breaking the localization caused by the resonator in a balanced state. The magnitude of the external acceleration is calculated by detecting the amplitude ratio of the resonator with a differential output.

[0082] Compared with the traditional mechanical coupling structure, the electrostatic coupling adopted in the present invention can adjust the coupling strength in real time and easily achieve low coupling stiffness. Figure 2 It is shown as an amplitude-frequency characteristic diagram of the acceleration sensor of the present invention when it is in a balanced state according to the dimensions in the structural parameter table 1 of the present invention in an embodiment of the present invention, wherein the abscissa is the frequency (kHz) and the ordinate is the amplitude (μm).

[0083] Table 1

[0084]

[0085] By applying a coupling voltage V on the first tuning fork beam c =70V. When there is no external acceleration disturbance, first select the AC voltage in the driving voltage source to be V0=10mV, and then continuously adjust the DC voltage V in the driving voltage source. dc Make the system in equilibrium, where V dc =35V, such as Figure 2 As shown, at this time, the amplitudes of the first tuning fork beam and the second tuning fork beam are the same.

[0086] Figure 3 1 is a curve showing a change in the amplitude-frequency characteristic of the resonator when an external 1g acceleration disturbance is applied in an embodiment of the present invention.

[0087] Figure 4 is the sensitivity condition when the relative amplitude ratio is used as the sensitivity output in the embodiment of the present invention, wherein Figure 4 (a) is the out-of-phase mode, Figure 4 (b) is the same phase mode, obtained by simulation in the range of 0-1g. Figure 5 is the sensitivity condition when the relative frequency is used as the sensitivity output in the embodiment of the present invention, wherein Figure 5 (a) is the anomaly mode, Figure 5 (b) is the in-phase mode, obtained by simulation in the range of 0-1g. The sensitivity output is three orders of magnitude higher than the frequency shift output, with the relative amplitude ratio as the sensitivity output.

[0088] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0089] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, the numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0090] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention: the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0091] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below their position devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0092] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A differential acceleration sensor based on modal localization effect, characterized in that: The differential acceleration sensor has a central symmetrical structure and includes: Mass block (1-9), A first coupler and a second coupler are symmetrically arranged on both sides of the mass block (1-9); the first coupler and the second coupler have the same structure; The first coupler comprises a first resonator and a second resonator which are symmetrically arranged; the first resonator and the second resonator have the same structure; The first resonator is composed of a first tuning fork beam (3-1); the first tuning fork beam (3-1) is an I-shaped beam; The second resonator is composed of a second tuning fork beam (2-1); The first tuning fork beam (3-1) is placed on the upper right side of the mass block (1-9). One end of the first tuning fork beam (3-1) is fixed by a first fixed end (3-4), and the other end of the first tuning fork beam (3-1) is fixed by a first micro-lever (4-1) and a second micro-lever (4-2); The second tuning fork beam (2-1) is located at the lower side of the first tuning fork beam (3-1), The second tuning fork beam (2-1) is placed on the lower right side of the mass block (1-9); Two ends of the second tuning fork beam (2-1) are respectively fixed by a second fixed end (2-4) and a third fixed end (2-5); The upper side of the mass block (1-9) is connected to the first anchor point (1-1) and the second anchor point (1-2), and the lower side of the mass block (1-9) is connected to the third anchor point (1-3) and the fourth anchor point (1-4); The upper side of the mass block (1-9) is connected to the first anchor point (1-1) and the second anchor point (1-2) respectively via a first support beam (1-5) and a second support beam (1-6), and the lower side is connected to the third anchor point (1-3) and the fourth anchor point (1-4) respectively via a third support beam (1-7) and a fourth support beam (1-8); The second anchor point (1-2) is connected to the first fixed end (3-4); The third anchor point (1-3) is connected to the second fixed end (2-4) and the third fixed end (2-5); The mass block (1-9) and the first tuning fork beam (3-1) amplify the inertial force of the mass block (1-9) and the force exerted on the first tuning fork beam (3-1) through a lever structure; The first tuning fork beam (3-1) and the second tuning fork beam (2-1) are coupled via electrostatic coupling, and a coupling power supply outputs a coupling voltage which is loaded on a first fixed end (3-4) connected to the first tuning fork beam (3-1), so as to adjust the electrostatic coupling strength between the first tuning fork beam (3-1) and the second tuning fork beam (2-1); The first tuning fork beam (3-1) adjusts the driving force through a first fixed excitation electrode (3-2); the second tuning fork beam (2-1) adjusts the driving force through a second fixed excitation electrode (2-2); The first tuning fork beam (3-1) and the second tuning fork beam (2-1) detect amplitude and frequency through a first detection electrode (3-3) and a second detection electrode (2-3) respectively.

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