CN117214554A - Modal localization electrometer based on nonlinear enhancement - Google Patents

Abstract

The invention discloses a mode localization electrometer based on nonlinear enhancement, which comprises two double-end fixedly supported tuning forks which are arranged in parallel, wherein the left end and the right end of the two double-end fixedly supported tuning forks are respectively fixed with two electrodes fixedly connected with a substrate insulating layer, so that the double-end fixedly supported tuning forks Liang Xuanzhi are arranged on a hollowed substrate; the excited polar plate extending out of the middle outer side of each double-end fixedly-supported tuning fork beam is matched with an excited polar plate, and vibration in the bending direction of the double-end fixedly-supported tuning fork beam is excited by the action of electrostatic force; the parallel electrode plates extending out of the middle inner sides of the two double-end fixedly-supported tuning fork beams interact through electrostatic force, and the magnitude of the mutual coupling effect is regulated through controlling the intermediate potential of the double-end fixedly-supported tuning fork beams; the invention improves the amplitude ratio sensitivity of two resonance Liang Tongxiang modes by utilizing the nonlinearity of the soft spring, and solves the problem that linear regions in the mode localized sensor limit sensing application.

Description

Modal localization electrometer based on nonlinear enhancement

Technical Field

The invention belongs to the technical field of micro-mechanical systems and nonlinear dynamics, and particularly relates to a modal localization electrometer based on nonlinear enhancement.

Background

As a measuring instrument for detecting extremely weak electric charges or potential differences, a micromechanical electrometer has been widely used in the fields of nuclear industry, biological detection, chemical analysis, and the like. Micro-scale MEMS devices have unparalleled economic and volumetric advantages in improving the dynamic measurement range and measurement accuracy of electrometers. How to improve the detection accuracy is a great challenge.

High sensitivity resonant sensors based on modal localization are of great interest. Amplitude variations of resonant sensors based on modal localization are highly sensitive to the measured object and less affected by the environment than frequency variations. However, the sensitivity of the current resonant sensor based on modal localization needs to be further improved, the operation of the resonator in the linear interval limits the bandwidth of the modal localization and its potential sensing applications to some extent, and the resonant sensor is easily driven to the nonlinear region due to the scale effect.

Disclosure of Invention

The invention aims to solve the technical problem of providing a mode localization electrometer based on nonlinear enhancement aiming at the defects in the prior art, and aims to improve the sensitivity of the amplitude ratio by driving vibration of a resonant sensor to a nonlinear region and utilizing a soft spring to nonlinear influence the mode localization amplitude ratio of two tuning fork vibration beams, so as to solve the technical problem of limiting sensing application of the linear region in the mode localization sensor.

The invention adopts the following technical scheme:

the utility model provides a mode localization electrometer based on nonlinear enhancement, includes the first two-terminal tuning fork roof beam and the second two-terminal tuning fork roof beam of arranging side by side, and first two-terminal tuning fork Liang Zhiyu is in the first tank circuit and connect first closed loop feedback, and second two-terminal tuning fork Liang Zhiyu is in the second tank circuit and connect second closed loop feedback, excites first two-terminal tuning fork roof beam and second two-terminal tuning fork roof beam through electrostatic force effect respectively and produces self-oscillation;

the first coupling electrode plate extending from the middle inner side of the first two-end tuning fork beam and the second coupling electrode plate extending from the middle inner side of the second two-end tuning fork beam interact through electrostatic force, and the magnitude of the interaction is adjusted by controlling the middle potential of the first two-end tuning fork beam and/or the second two-end tuning fork beam;

the second oscillation circuit is connected with the perturbation polar plate and used for providing a perturbation bias voltage, and the effective rigidity of the second double-end supporting tuning fork beam is changed through the action of electrostatic force; the driving amplitude of the first two-end tuning fork beam is increased, so that the first two-end tuning fork beam and the second two-end tuning fork beam vibrate in a nonlinear region, and the sensitivity is improved by utilizing the nonlinearity of the soft spring.

Specifically, a first stimulated polar plate extending from the middle outer side of the tuning fork beam is fixedly supported at the first two ends and matched with a first stimulated polar plate extending from the third metal electrode layer; the first double-end supporting tuning fork beam, the first stimulated polar plate, the first coupling polar plate and the first stimulated polar plate are suspended on a hollowed substrate, and the first stimulated polar plate form a capacitor polar plate; the left end and the right end of the first two-end supporting tuning fork beam are respectively connected with a first anchor point and a second anchor point which are fixedly connected with the insulating layer of the substrate; the first anchor point and the second anchor point are respectively sputtered with a first metal electrode layer and a second metal electrode layer, and the third metal electrode layer is sputtered on the third anchor point.

Further, the length of the tuning fork beam at the first two ends is 250-500 mu m; the lengths of the first stimulated polar plate, the first stimulated polar plate and the first coupling polar plate are 100-200 mu m; the gap distance between the first stimulated polar plate and the first stimulated polar plate is 2-6 mu m; the first anchor point, the second anchor point and the third anchor point are rectangular structures, and the side length is 150-300 mu m; the first metal electrode layer, the second metal electrode layer and the third metal electrode layer are rectangular structures, and the side length dimension is 100-250 mu m.

Further, the first metal electrode layer and the second metal electrode layer are connected with the third metal electrode layer through a first closed loop feedback, and the signal generated by the first closed loop feedback provides an excitation voltage V while outputting the first double-ended fixed tuning fork Liang Fuzhi _ac1 With a bias voltage V _dc1 The first two-end supporting tuning fork beam is enabled to perform self-oscillation by acting on the third metal electrode layer; the first closed loop feedback includes a first oscillator including a first differential amplifier, a first filter, a first phase shifter, and a first comparator connected in sequence.

Specifically, a second excited polar plate extending out of the middle outer side of the second double-end supporting tuning fork beam is matched with a second excited polar plate extending out of the sixth metal electrode layer; the second double-end supporting tuning fork beam, the second stimulated polar plate, the second coupling polar plate and the second stimulated polar plate are suspended on the hollowed substrate, and the second stimulated polar plate form a capacitor polar plate; the perturbation polar plate is sputtered on the seventh anchor point and is arranged above the second double-end supporting tuning fork beam; the left end and the right end of the second two-end supporting tuning fork beam are respectively connected with a fourth anchor point and a fifth anchor point which are fixedly connected with the insulating layer of the substrate; and a fourth metal electrode layer and a fifth metal electrode layer are respectively sputtered on the fourth anchor point and the fifth anchor point, and a sixth metal electrode layer is sputtered on the sixth anchor point.

Further, the length of the second two-end supporting tuning fork beam is 250-500 mu m; the lengths of the second stimulated polar plate, the second stimulated polar plate and the second coupling polar plate are 100-200 mu m; the gap distance between the second stimulated polar plate and the second stimulated polar plate is 2-6 mu m; the fourth anchor point, the fifth anchor point and the sixth anchor point are rectangular structures, and the side length is 150-300 mu m; the seventh anchor point is of a rectangular structure, and the side length is 150-600 mu m; the fourth metal electrode layer, the fifth metal electrode layer, the sixth metal electrode layer and the perturbation pole plate are rectangular structures, and the side length is 100-250 mu m.

Specifically, the fourth metal electrode layer and the fifth metal electrode layer are connected with the sixth metal electrode layer through second closed loop feedback and are used for guaranteeing self-oscillation and stable amplitude output of the second two-end supporting tuning fork beam; the second closed loop feedback includes a second oscillator including a second differential amplifier, a second filter, a second phase shifter, and a second comparator connected in sequence.

Specifically, the gap distance between the first coupling polar plate and the second coupling polar plate is 2-6 mu m.

Specifically, by alternating current signal V _ac1 cos(ω _d t) match bias voltage V _dc1 Exciting the first two-end supporting tuning fork beam to do forced motion; the second double-end supporting tuning fork beam is subjected to disturbance bias voltage V applied by a perturbation polar plate _p The charge quantity of the second two-end supporting tuning fork beam is changed; by perturbing bias V _p The amplitude of the first two-end tuning fork beam and the second two-end tuning fork beam is dynamically changed under the regulation and control action of the tuning fork beam, so that the dynamic regulation and control of the equidirectional modal amplitude ratio is realized; the first two-terminal tuning fork beam enters a nonlinear vibration region by increasing the excitation intensity on the first two-terminal tuning fork beam to increase the vibration amplitude of the first two-terminal tuning fork beam.

Further, in the nonlinear state, the sensitivity S of the same-directional modal amplitude ratio is:

wherein, kappa is the coupling strength, gamma is the nonlinear coefficient, χ is the amplitude ratio, a is the amplitude of the first two-end-supported tuning fork beam

Compared with the prior art, the invention has at least the following beneficial effects:

the utility model provides a mode localization electrometer based on nonlinearity reinforcing, firstly through increasing the excitation intensity of first two-terminal support tuning fork girder, because scale effect easily excites the vibration of first two-terminal support tuning fork girder to nonlinear state, and nonlinear existence can improve sensitivity and resolution ratio of resonator by a wide margin; secondly, the rigidity regulation and control of the second two-end supporting tuning fork beam is derived from coupling electrostatic force, and the adjustable resonator system can limit the amplitude ratio in a fixed interval range; finally, by changing the bias voltage, the change of the charge quantity can be detected in real time, the response speed is high, the instantaneity is good, and the stability is high.

Further, a first closed loop feedback is provided to excite the vibration of the first two-end fixed tuning fork beam, and the amplitude is read in real time. The signal generated by the first closed loop feedback outputs the amplitude of the first double-ended tuning fork beam and simultaneously provides the excitation voltage V _ac1 With a bias voltage V _dc1 And acting on the third metal electrode layer to cause forced oscillation of the first two-end supporting tuning fork beam.

Further, a second closed loop feedback is provided to excite self-oscillation of the second two-end tuning fork beam, and the amplitude is read in real time.

Furthermore, electrostatic coupling is generated between the first coupling polar plate and the second coupling polar plate through the action of electrostatic force, the magnitude of the electrostatic coupling force can be changed through bias voltage, and flexible adjustment of coupling strength is realized.

Further, the first closed loop feedback excites the oscillation of the first two-end tuning fork beam, and the two ends of the first two-end tuning fork beam generate dynamic current flowing through the first two-end tuning fork beam due to potential difference, and simultaneously provide an alternating voltage signal V _ac1 cos(ω _d t), and bias voltage V _dc1 Acting on the tuning fork beams at the first two ends together to generate forced oscillation; the second closed loop feedback excites the self-oscillation of the second two-end supporting tuning fork beam, and the second two-end supporting tuning fork beam is subjected to disturbance bias voltage V applied by a perturbation polar plate _p The charge quantity of the second two-end supporting tuning fork beam is changed, so that the change of effective rigidity is influenced; by perturbing bias V _p The amplitude of the first two-end tuning fork beam and the second two-end tuning fork beam can be dynamically changed, so that the amplitude ratio of the same-direction mode can be dynamically regulated and controlled, and the aim of detecting external disturbance is fulfilled; the excitation intensity on the first two-end tuning fork beam is increased to increase the vibration amplitude of the first two-end tuning fork beam, so that the first two-end tuning fork beam enters a nonlinear vibration area, and the sensitivity of the same-direction modal amplitude ratio can be improved by utilizing the nonlinearity of the soft spring.

In conclusion, the method can detect the quantity of the change of the charge quantity in real time, and has the characteristics of accuracy, controllability, good instantaneity, high resolution and high stability.

The technical scheme of the invention is further described in detail through the drawings and the embodiments.

Drawings

FIG. 1 is a diagram of a MEMS resonant beam structure with a modal localization mechanism in an embodiment of the invention;

FIG. 2 is a schematic diagram illustrating the operation of a mode localization mechanism according to an embodiment of the present invention;

fig. 3 is a graph showing an amplitude-frequency response of the first two-terminal tuning fork beam in an on-line state obtained by performing an open-loop frequency sweep, wherein (a) is the first two-terminal tuning fork beam, and (b) is the second two-terminal tuning fork beam.

Fig. 4 is a graph showing an amplitude-frequency response in a nonlinear state obtained by performing an open-loop frequency sweep on a first two-terminal tuning fork beam, wherein (a) is the first two-terminal tuning fork beam, and (b) is the second two-terminal tuning fork beam.

FIG. 5 is a graph of the amplitude ratio of the in-phase mode versus the disturbance stiffness for an open-loop frequency sweep at different drive force amplitudes.

Fig. 6 is a graph showing the amplitude ratio sensitivity as a function of the driving force amplitude from a linear section to a nonlinear section.

Wherein: 1-1, a first metal electrode layer; 1-2, a first anchor point; 1-3, a tuning fork beam is fixedly supported at the first two ends; 1-4, a first stimulated polar plate; 1-5, a first coupling polar plate; 1-6. A second metal electrode layer; 1-7, a second anchor point; 2-1, a fourth metal electrode layer; 2-2, a fourth anchor point; 2-3, supporting a tuning fork beam at the second two ends; 2-4, a second stimulated polar plate; 2-5, a second coupling polar plate; 2-6, fifth metal electrode layer; 2-7, a fifth anchor point; 3-1, a third metal electrode layer; 3-2, a third anchor point; 3-3, a first excitation polar plate; 4-1, a sixth metal electrode layer; 4-2, a sixth anchor point; 4-3, a second excitation polar plate; 5-1, perturbation polar plates; 5-2, a seventh anchor point; 6. a first differential amplifier; 7. a first filter; 8. a first phase shifter; 9. a first comparator; 10. a second differential amplifier; 11. a second filter; 12. a second phase shifter; 13. and a second comparator.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "one side", "one end", "one side", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, unless otherwise indicated, the meaning of "a plurality" is two or more.

In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.

It should be understood that the terms "comprises" and "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

It is also to be understood that the terminology used in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this specification and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It should be further understood that the term "and/or" as used in the present specification and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes such combinations.

Various structural schematic diagrams according to the disclosed embodiments of the present invention are shown in the accompanying drawings. The figures are not drawn to scale, wherein certain details are exaggerated for clarity of presentation and may have been omitted. The shapes of the various regions, layers and their relative sizes, positional relationships shown in the drawings are merely exemplary, may in practice deviate due to manufacturing tolerances or technical limitations, and one skilled in the art may additionally design regions/layers having different shapes, sizes, relative positions as actually required.

The invention provides a nonlinear enhancement-based modal localization electrometer, which changes the charge quantity of a second two-end tuning fork beam by changing disturbance bias voltage, so as to change the effective rigidity of the second two-end tuning fork beam, dynamically regulate and control the vibration amplitude of a first two-end tuning fork beam and a second two-end tuning fork beam, and further change the same-direction modal amplitude ratio of the first two-end tuning fork beam and the second two-end tuning fork beam, thereby achieving the purpose of detecting external disturbance. The disturbance bias voltage is applied to the second double-end tuning fork beam through the electrostatic action of the perturbation polar plate, the amplitude changes of the first double-end tuning fork beam and the second double-end tuning fork beam are regulated and controlled in real time, the excitation intensity of the first double-end tuning fork beam is increased, the first double-end tuning fork beam enters a nonlinear vibration area, and the sensitivity of the resonator can be improved. The invention realizes flexible regulation and control of the sensitivity of the resonator in mode localization, greatly improves the sensitivity of the resonator by utilizing the nonlinearity of the soft spring, and overcomes the problem that the sensing application is limited by the linear region. Based on the method, the application requirements of high-sensitivity measurement of the resonant sensor can be met, and the overall performance of the resonant sensor is greatly improved.

Referring to FIG. 1, the mode localization electrometer based on nonlinear enhancement of the invention comprises a first two-end supporting tuning fork beam 1-3 and a second two-end supporting tuning fork beam 2-3; the first double-end tuning fork beam 1-3 and the second double-end tuning fork beam 2-3 are arranged in parallel, and electrostatic coupling is realized through the first coupling polar plate 1-5 and the second coupling polar plate 2-5; the first two-end tuning fork beam 1-3 is arranged in a first oscillation circuit, the second two-end tuning fork beam 2-3 is arranged in a second oscillation circuit, a first coupling electrode plate 1-5 extending from the inner side of the middle of the first two-end tuning fork beam 1-3 and a second coupling electrode plate 2-5 extending from the inner side of the middle of the second two-end tuning fork beam 2-3 interact through electrostatic force, and the magnitude of the interaction is regulated through controlling the intermediate potential of the first two-end tuning fork beam 1-3 and the second two-end tuning fork beam 2-3; the second excited polar plate 2-4 extending out of the middle outer side of the second two-end supporting tuning fork beam 2-3 is matched with the second excited polar plate 4-3 extending out of the sixth metal electrode layer 4-1, and vibration in the bending direction of the second two-end supporting tuning fork beam 2-3 is excited by the action of electrostatic force to generate self-excited oscillation; the perturbation polar plate 5-1 provides a perturbation bias voltage for the second oscillation circuit, and the charge quantity of the second double-end supporting tuning fork beam 2-3 is changed under the action of electrostatic force, so that the effective rigidity of the second double-end supporting tuning fork beam 2-3 is changed; amplitude-frequency responses of the first two-end tuning fork beam 1-3 and the second two-end tuning fork beam 2-3 are respectively obtained by a first closed-loop feedback and a second closed-loop feedback; the amplitudes of the first two-end tuning fork beam 1-3 and the second two-end tuning fork beam 2-3 jump due to the change of effective rigidity, and the amplitude ratio of the same-direction modes changes accordingly, so that the detection of external disturbance can be realized. Based on the modal localization principle, the excitation intensity of the first two-end tuning fork beam 1-3 is increased, so that the first two-end tuning fork beam 1-3 and the second two-end tuning fork beam 2-3 enter a nonlinear vibration area, and the sensitivity of the electrometer is greatly improved by utilizing the nonlinearity of the soft spring.

Referring to fig. 2, the first tank circuit includes a first metal electrode layer 1-1, a first anchor point 1-2, a first two-terminal tuning fork beam 1-3, a first excited electrode plate 1-4, a first coupling electrode plate 1-5, a second metal electrode layer 1-6, a second anchor point 1-7, a third metal electrode layer 3-1, a third anchor point 3-2, a first excited electrode plate 3-3, a first differential amplifier 6, a first filter 7, a first phase shifter 8, and a first comparator 9.

The second oscillation circuit comprises a fourth metal electrode layer 2-1, a fourth anchor point 2-2, a second double-end supporting tuning fork beam 2-3, a second stimulated polar plate 2-4, a second coupling polar plate 2-5, a fifth metal electrode layer 2-6, a fifth anchor point 2-7, a sixth metal electrode layer 4-1, a sixth anchor point 4-2, a second stimulated polar plate 4-3, a seventh anchor point 5-2 and a perturbation polar plate 5-1.

The first two-end supporting tuning fork beam 1-3 is suspended on a hollowed substrate, and the left and right ends of the first two-end supporting tuning fork beam 1-3 are respectively connected with a first anchor point 1-2 and a second anchor point 1-7 which are fixedly connected with an insulating layer of the substrate; the first excited polar plate 1-4 which extends outwards from the middle of the first two-end tuning fork beam 1-3 is suspended on a hollowed substrate, the first coupling polar plate 1-5 which extends outwards from the middle of the first two-end tuning fork beam 1-3 is suspended on the hollowed substrate, the first excited polar plate 3-3 which extends outwards from the third anchor point 3-2 is suspended on the hollowed substrate, the first excited polar plate 1-4 and the first excited polar plate 3-3 form a capacitor polar plate, and electrostatic exciting force is provided for the first two-end tuning fork beam 1-3; the first anchor point 1-2, the second anchor point 1-7 and the third anchor point 3-2 are respectively sputtered with a first metal electrode layer 1-1, a second metal electrode layer 1-6 and a third metal electrode layer 3-1 for transmission of electric signals.

The second two-end supporting tuning fork beam 2-3 is suspended on the hollowed substrate, and the left and right ends of the second two-end supporting tuning fork beam 2-3 are respectively connected with a fourth anchor point 2-2 and a fifth anchor point 2-7 which are fixedly connected with the insulating layer of the substrate; the second excited polar plate 2-4 which extends outwards from the middle of the second double-end tuning fork beam 2-3 is suspended on the hollowed substrate, the second coupling polar plate 2-5 which extends outwards from the middle of the second double-end tuning fork beam 2-3 is suspended on the hollowed substrate, the second excited polar plate 4-3 which extends outwards from the sixth anchor point 4-2 is suspended on the hollowed substrate, the second excited polar plate 2-4 and the second excited polar plate 4-3 form a capacitor polar plate, and self-excitation oscillation and stable amplitude output of the second double-end tuning fork beam 2-3 are ensured; the fourth anchor point 2-2, the fifth anchor point 2-7 and the sixth anchor point 4-2 are respectively sputtered with a fourth metal electrode layer 2-1, a fifth metal electrode layer 2-6 and a sixth metal electrode layer 4-1 for transmitting electric signals; the seventh anchor 5-2 is sputtered with a perturbation plate 5-1 for providing perturbation bias.

The first oscillation circuit is connected with a first closed loop feedback, and the bias voltage V _d1 And V _d2 When the first two-end tuning fork beam 1-3 vibrates, the resistance of the first two-end tuning fork beam 1-3 changes due to piezoresistive effect, so that dynamic current flowing through the first two-end tuning fork beam 1-3 is generated; the first differential amplifier 6 is internally provided with a trans-impedance amplifier, converts the dynamic current signal into a voltage signal and improves the signal-to-noise ratio of the voltage signal; the voltage signal is input to a first filter 7 through the action of a first differential amplifier 6, and the higher harmonic is filtered; the first phase shifter 8 controls the phase difference between the polar plate oscillation signal and the feedback signal; the first comparator 9 outputs phase information while providing an alternating voltage signal V _ac1 cos(ω _d t), and bias voltage V _dc1 Acting on the first two-end supporting tuning fork beams 1-3 together to generate simple harmonic oscillation;

the second closed loop feedback is connected in the second oscillation circuit, and the bias voltage V _d3 And V _d4 When the second two-end tuning fork beam 2-3 vibrates, the resistance of the second two-end tuning fork beam 2-3 changes due to piezoresistive effect, so that dynamic current flowing through the second two-end tuning fork beam 2-3 is generated; the second differential amplifier 10 has a built-in transimpedance amplifier to convert the dynamic current signal into a voltage signal and to improve the signal-to-noise ratio of the voltage signalThe method comprises the steps of carrying out a first treatment on the surface of the The voltage signal is input to a second filter 11 through the action of a second differential amplifier 10, and the higher harmonic is filtered; the second phase shifter 12 controls a phase difference between the plate oscillation signal and the feedback signal; the second comparator 13 outputs phase information to ensure self-oscillation of the second two-end supporting tuning fork beams 2-3; the second two-end supporting tuning fork beam 2-3 is subjected to disturbance bias voltage V applied by the perturbation polar plate 5-1 _p The effect is that the charge quantity of the second two-end supporting tuning fork beam 2-3 is changed, and the change of the effective rigidity is further affected. By perturbing bias V _p The amplitude of the first two-end tuning fork beam 1-3 and the second two-end tuning fork beam 2-3 can be dynamically changed, and the amplitude ratio of the same-direction mode can be dynamically adjusted.

The first coupling plate 1-5 and the second coupling plate 2-5 form a capacitive plate, generating an electrostatic coupling force, the magnitude of which depends on the potential difference between the coupling plates.

The potential difference between the first coupling plate 1-5 and the second coupling plate 2-5 is DeltaV, deltaV being dependent on the bias voltage V _d1 、V _d2 、V _d3 And V _d4 By adjusting the bias voltage V _d1 、V _d2 、V _d3 And V _d4 The invention can flexibly regulate and control the electrostatic coupling force;

the potential difference DeltaV is:

ΔV＝(V _d1 +V _d2 -V _d3 -V _d4 )/2

the second double-end supporting tuning fork beam 2-3 realizes the regulation and control of self equivalent rigidity through the action of the electrostatic force of the perturbation polar plate, and the first double-end supporting tuning fork beam 1-3 and the second double-end supporting tuning fork beam 2-3 realize modal coupling through electrostatic coupling force.

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The first two-end supporting tuning fork beam 1-3 has the length of 250-500 mu m, the width of 5-20 mu m and the thickness of 15-30 mu m.

The second two-end supporting tuning fork beam 2-3 has the length of 250-500 mu m, the width of 5-20 mu m and the thickness of 15-30 mu m.

The first stimulated polar plate 1-4, the second stimulated polar plate 2-4, the first stimulated polar plate 3-3, the second stimulated polar plate 4-3, the first coupling polar plate 1-5 and the second coupling polar plate 2-5 have the length of 100-200 mu m, the width of 5-10 mu m and the thickness of 15-30 mu m.

The first anchor point 1-2, the second anchor point 1-7, the third anchor point 3-2, the fourth anchor point 2-2, the fifth anchor point 2-7 and the sixth anchor point 4-2 are rectangular structures, and the side length size is 150-300 mu m.

The seventh anchor point 5-2 is rectangular structure, and the side length is 150-600 μm.

The first metal electrode layer 1-1, the second metal electrode layer 1-6, the third metal electrode layer 3-1, the fourth metal electrode layer 2-1, the fifth metal electrode layer 2-6, the sixth metal electrode layer 4-1 and the perturbation pole plate are rectangular structures, and the side length dimension is 100-250 mu m.

The first stimulated polar plate 1-4 and the first stimulated polar plate 3-3, the second stimulated polar plate 2-4 and the second stimulated polar plate 4-3, the gap distance between the first coupling polar plate 1-5 and the second coupling polar plate 2-5 is 2-6 mu m.

And performing an open-loop characterization experiment on the first double-end tuning fork beam 1-3 and the second double-end tuning fork beam 2-3 with the structural dimensions, exciting the first double-end tuning fork beam 1-3 under the condition of weak coupling, and increasing excitation strength to enable the first double-end tuning fork beam 1-3 and the second double-end tuning fork beam 2-3 to vibrate in a nonlinear region.

The dynamic models of the first two-terminal tuning fork beam 1-3 and the second two-terminal tuning fork beam 2-3 are as follows:

wherein x and y are equivalent displacements of the first two-end supporting tuning fork beam 1-3 and the second two-end supporting tuning fork beam 2-3 respectively; m is the equivalent mass of the first two-end supporting tuning fork beam 1-3 and the second two-end supporting tuning fork beam 2-3; Γ is normalized damping; omega ₀ The natural frequencies of the first two-end supporting tuning fork beam 1-3 and the second two-end supporting tuning fork beam 2-3 are adopted; kappa coupling stiffness; delta is the disturbance stiffness applied to the second two-terminal tuning fork beam 2-3; gamma is the nonlinear rigidity of the first two-end supporting tuning fork beam 1-3 and the second two-end supporting tuning fork beam 2-3; f is the external excitation intensity of the first two-end supporting tuning fork beam 1-3; omega _d The external excitation frequency of the tuning fork beams 1-3 is supported for the first two ends.

The relationship between the charge amount and the disturbance stiffness δ is as follows:

wherein,for electrostatic force caused by charge, q is the charge input, l is the length of the second high frequency resonant beam, A is the overlap area of the drive capacitance, ε ₀ Is the dielectric constant in vacuum.

In a nonlinear state, the expression of the equidirectional modal amplitude ratio sensitivity S is as follows:

wherein,is the amplitude ratio of the first two-end tuning fork beam 1-3 to the second two-end tuning fork beam 2-3.

Referring to fig. 3, in the on-line state, the amplitude-frequency response diagram of the first two-terminal tuning fork beam 1-3 and the amplitude-frequency response diagram of the second two-terminal tuning fork beam 2-3 are shown; the displacement peak value of the resonance beam shifts along with delta change, and modal localization occurs.

Referring to fig. 4, in a nonlinear state, the amplitude-frequency response diagram of the first two-terminal tuning fork beam 1-3 and the amplitude-frequency response diagram of the second two-terminal tuning fork beam 2-3; the amplitude-frequency response curve exhibits significant soft spring nonlinearity.

Referring to fig. 5, the amplitude ratio of the first two-terminal tuning fork beam 1-3 and the second two-terminal tuning fork beam 2-3 is plotted against the disturbance stiffness. The slope of the curve increases significantly with increasing magnitude of the driving force.

Referring to fig. 6, under different driving force amplitudes, the co-directional modal amplitude ratio χ varies with the stiffness disturbance δ; when the driving amplitude is weak, the coupling system vibrates in a linear state, and the sensitivity is almost constant; the driving amplitude is enhanced, and the sensitivity is remarkably improved. Sensitivity is significantly enhanced by the presence of softening nonlinearities.

According to the invention, through modal coupling of the first two-end tuning fork beam and the second two-end tuning fork beam, disturbance bias is applied to the second two-end tuning fork beam, so that the charge quantity of the second two-end tuning fork beam is changed, the equivalent stiffness is changed, and the amplitude ratio of the first two-end tuning fork beam and the second two-end tuning fork beam is dynamically regulated. The resonator is excited to vibrate in a nonlinear region, and the sensitivity of amplitude comparison to external disturbance is enhanced by utilizing the nonlinearity of the soft spring.

Specifically, when the driving amplitude is smaller, the vibration of the first two-end tuning fork beam and the second two-end tuning fork beam is in a linear region, and the sensitivity is hardly changed; by increasing the driving amplitude, the vibration of the first two-end tuning fork beam and the second two-end tuning fork beam is in a nonlinear region, the sensitivity is obviously increased along with the nonlinear increase, and the aim of improving the sensitivity is fulfilled.

In summary, the modal localization electrometer based on nonlinear enhancement disclosed by the invention is based on a modal localization principle, and the amplitude ratio sensitivity of two resonant beams is improved by utilizing the nonlinearity of a soft spring, so that the problem that linear area in a modal localization sensor limits sensing application is solved; in addition, the invention realizes the coupling between the resonance beams by utilizing electrostatic force, realizes flexible coupling strength control, and further realizes flexible regulation and control of linear bandwidth expansion range; the method has the advantages of no thermal noise, excellent real-time performance, high regulation precision and the like, and the indexes such as the real-time performance, the measurement precision, the measuring range and the like of the sensor based on the modal localization principle are obviously improved.

The above is only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited by this, and any modification made on the basis of the technical scheme according to the technical idea of the present invention falls within the protection scope of the claims of the present invention.

Claims (10)

1. The modal localization electrometer based on nonlinear enhancement is characterized by comprising a first double-end supporting tuning fork beam (1-3) and a second double-end supporting tuning fork beam (2-3) which are arranged in parallel, wherein the first double-end supporting tuning fork beam (1-3) is arranged in a first oscillation circuit and is connected with a first closed-loop feedback, the second double-end supporting tuning fork beam (2-3) is arranged in a second oscillation circuit and is connected with a second closed-loop feedback, and the first double-end supporting tuning fork beam (1-3) and the second double-end supporting tuning fork beam (2-3) are excited by electrostatic force to generate self-oscillation;

the first coupling electrode plate (1-5) extending from the middle inner side of the first two-end supporting tuning fork beam (1-3) and the second coupling electrode plate (2-5) extending from the middle inner side of the second two-end supporting tuning fork beam (2-3) interact through electrostatic force, and the magnitude of the interaction is adjusted by controlling the middle potential of the first two-end supporting tuning fork beam (1-3) and/or the second two-end supporting tuning fork beam (2-3);

the second oscillation circuit is connected with the perturbation polar plate (5-1) and is used for providing a perturbation bias voltage, and the effective rigidity of the second double-end supporting tuning fork beam (2-3) is changed through the action of electrostatic force; the driving amplitude of the first two-end tuning fork beam (1-3) is increased, so that the first two-end tuning fork beam (1-3) and the second two-end tuning fork beam (1-3) vibrate in a nonlinear region, and the sensitivity is improved by utilizing the nonlinearity of a soft spring.

2. The nonlinear enhancement-based modal localization electrometer of claim 1, wherein a first excited plate (1-4) extending outside the middle of the first two-terminal tuning fork beam (1-3) mates with a first excited plate (3-3) extending from the third metal electrode layer (3-1); the first two-end supporting tuning fork beam (1-3), the first stimulated polar plate (1-4), the first coupling polar plate (1-5) and the first stimulated polar plate (3-3) are suspended on a hollowed substrate, and the first stimulated polar plate (1-4) and the first stimulated polar plate (3-3) form a capacitor polar plate; the left end and the right end of the first two-end supporting tuning fork beam (1-3) are respectively connected with a first anchor point (1-2) and a second anchor point (1-7) which are fixedly connected with the insulating layer of the substrate; the first anchor point (1-2) and the second anchor point (1-7) are respectively sputtered with a first metal electrode layer (1-1) and a second metal electrode layer (1-6), and the third metal electrode layer (3-1) is sputtered on the third anchor point (3-2).

3. The localized electrometer of mode based on nonlinear enhancement according to claim 2, wherein the length of the first two-terminal supporting tuning fork beam (1-3) is 250 to 500 μm; the lengths of the first stimulated polar plate (1-4), the first stimulated polar plate (3-3) and the first coupling polar plate (1-5) are 100-200 mu m; the gap distance between the first stimulated polar plate (1-4) and the first stimulated polar plate (3-3) is 2-6 mu m; the first anchor point (1-2), the second anchor point (1-7) and the third anchor point (3-2) are rectangular structures, and the side length is 150-300 mu m; the first metal electrode layer (1-1), the second metal electrode layer (1-6) and the third metal electrode layer (3-1) are rectangular structures, and the side length dimension is 100-250 mu m.

4. A non-linear enhancement based modal localization electrometer as claimed in claim 3 wherein the first metal electrode layer (1-1) and the second metal electrode layer (1-6) are connected to the third metal electrode layer (3-1) via a first closed loop feedback, the signal generated by the first closed loop feedback being output at the output of the firstAn excitation voltage V is provided while the amplitude of the tuning fork beam (1-3) is fixed at both ends _ac1 With a bias voltage V _dc1 The first two-end supporting tuning fork beam (1-3) performs self-oscillation by acting on the third metal electrode layer (3-1); the first closed loop feedback comprises a first oscillator comprising a first differential amplifier (6), a first filter (7), a first phase shifter (8) and a first comparator (9) connected in sequence.

5. The nonlinear enhancement-based modal localization electrometer of claim 1 wherein a second excited plate (2-4) extending outward from the middle of the second two-terminal tuning fork beam (2-3) mates with a second excited plate (4-3) extending from the sixth metal electrode layer (4-1); the second double-end supporting tuning fork beam (2-3), the second stimulated polar plate (2-4), the second coupling polar plate (2-5) and the second stimulated polar plate (4-3) are suspended on a hollowed substrate, and the second stimulated polar plate (2-4) and the second stimulated polar plate (4-3) form a capacitor polar plate; the perturbation polar plate (5-1) is sputtered on the seventh anchor point (5-2) and is arranged above the second double-end supporting tuning fork beam (2-3); the left end and the right end of the second two-end supporting tuning fork beam (2-3) are respectively connected with a fourth anchor point (2-2) and a fifth anchor point (2-7) which are fixedly connected with the insulating layer of the substrate; a fourth metal electrode layer (2-1) and a fifth metal electrode layer (2-6) are respectively sputtered on the fourth anchor point (2-2) and the fifth anchor point (2-7), and a sixth metal electrode layer (4-1) is sputtered on the sixth anchor point (4-2).

6. The localized electrometer of mode based on nonlinear enhancement according to claim 5, wherein the second two-terminal tuning fork beam (2-3) has a length of 250 to 500 μm; the lengths of the second stimulated polar plate (2-4), the second stimulated polar plate (4-3) and the second coupling polar plate (2-5) are 100-200 mu m; the gap distance between the second stimulated polar plate (2-4) and the second stimulated polar plate (4-3) is 2-6 mu m; the fourth anchor point (2-2), the fifth anchor point (2-7) and the sixth anchor point (4-2) are rectangular structures, and the side length is 150-300 mu m; the seventh anchor point (5-2) is of a rectangular structure, and the side length is 150-600 mu m; the fourth metal electrode layer (2-1), the fifth metal electrode layer (2-6), the sixth metal electrode layer (4-1) and the perturbation pole plate (5-1) are rectangular structures, and the side length is 100-250 mu m.

7. The modal localization electrometer based on nonlinear enhancement according to claim 1, characterized in that the fourth metal electrode layer (2-1) and the fifth metal electrode layer (2-6) are connected to the sixth metal electrode layer (4-1) via a second closed loop feedback for ensuring self-oscillation and stable amplitude output of the second two-terminal tuning fork beam (2-3); the second closed loop feedback comprises a second oscillator comprising a second differential amplifier (10), a second filter (11), a second phase shifter (12) and a second comparator (13) connected in sequence.

8. The non-linear enhancement based modal localization electrometer of claim 1 wherein the gap distance of the first coupling plate (1-5) and the second coupling plate (2-5) is 2-6 μιη.

9. The non-linear enhancement based modal localization electrometer of any one of claims 1 to 8 wherein the signal V is transmitted by an alternating current signal _ac1 cos(ω _d t) match bias voltage V _dc1 Exciting the first two-end supporting tuning fork beams (1-3) to do forced movement; the second two-end supporting tuning fork beam (2-3) is subjected to disturbance bias voltage V applied by a perturbation polar plate (5-1) _p The charge quantity of the second two-end supporting tuning fork beam (2-3) is changed; by perturbing bias V _p The amplitude of the first two-end supporting tuning fork beam (1-3) and the amplitude of the second two-end supporting tuning fork beam (2-3) are dynamically changed through the regulation and control function, so that the dynamic regulation and control of the equidirectional modal amplitude ratio are realized; the first two-end tuning fork beam (1-3) enters a nonlinear vibration region by increasing the excitation intensity on the first two-end tuning fork beam (1-3) to increase the vibration amplitude of the first two-end tuning fork beam (1-3).

10. The nonlinear-enhancement-based modal localization electrometer of claim 9 wherein in a nonlinear state the equidirectional modal amplitude ratio sensitivity S is:

wherein, kappa is coupling strength, gamma is nonlinear coefficient, χ is amplitude ratio, and a is amplitude of the first two-terminal tuning fork beam.