Thermal resistance-compression resonant accelerometer with axial expansion mode

Abstract

The invention discloses a thermal resistance-compression resonant accelerometer in an axial expansion mode, and belongs to the field of micro electro mechanical systems. Comprising an inertia force sensitive module and two sets of frequency modulation modules symmetrically connected to the two ends of the inertia force sensitive module, the inertia force sensitive module senses acceleration and converts the acceleration into inertia force applied to the two sets of frequency modulation modules, and the loading direction of the inertia force is perpendicular to the vibration direction of the two sets of frequency modulation modules; the frequency modulation module forms alternating thermal expansion force through a closed loop in the frequency modulation module, and self-oscillation of the frequency modulation module is completed under the action of the alternating thermal expansion force. The problems that an existing accelerometer is complex in control circuit, high in power consumption and the like are solved.

Description

Technical Field

[0001] The invention belongs to the field of micro-electromechanical systems, and in particular relates to a thermal piezoresistive resonant accelerometer in an axial expansion mode. Background Art

[0002] MEMS sensor is the abbreviation of Micro-Electro-Mechanical Systems, which is an important branch of MEMS devices. These sensors usually use MEMS manufacturing technology to integrate micro-mechanical structures and electronic circuits on the same chip to achieve the perception and conversion of various physical, chemical or biological parameters. MEMS sensors are widely used in many fields such as automobiles, medical treatment, consumer electronics, aerospace, etc. due to their small size, light weight, low power consumption, fast response and high precision.

[0003] Ultra-low power MEMS accelerometers are widely used in many fields due to their excellent power consumption performance and high accuracy. For example, they can be used to monitor human physiological activities, such as heart rate, respiratory rate, etc., and are suitable for wearable medical devices and remote health monitoring systems; in industrial environments, these sensors can be used for machine vibration analysis, structural health monitoring and process control, etc., which help improve production efficiency and safety; in consumer electronics such as smartphones, tablets, game controllers, etc., MEMS accelerometers are used for functions such as motion sensing, tilt detection and gesture recognition; in the automotive industry, MEMS accelerometers can be used for vehicle stability control, collision detection and anti-lock braking systems, etc.; ultra-low power MEMS accelerometers are also an important part of IoT devices, they can be used for environmental monitoring, asset tracking and smart home systems, etc.

[0004] In high-performance micro-nano sensors, the power consumption of the control circuit often accounts for the majority of the energy consumption. Taking high-precision resonant accelerometers as an example, most of their power consumption is used to generate heat for electronic components in the frequency tracking system, which becomes the main bottleneck limiting their performance. Summary of the invention

[0005] Technical issues to be solved:

[0006] In order to avoid the shortcomings of the prior art, the present invention provides a thermal piezoresistive resonant accelerometer with an axial expansion mode, in which an inertial force sensitive module loads the inertial force vertically to the vibration direction of the resonator of the frequency modulation module to reduce the overall stiffness of the structure and improve the sensitivity, thereby further realizing acceleration detection. At the same time, the problems of complex control circuits and high power consumption of existing accelerometers are solved.

[0007] The technical solution of the present invention is: a thermal piezoresistive resonant accelerometer with an axial expansion mode, comprising an inertial force sensitive module and two groups of frequency modulation modules symmetrically connected at both ends thereof, wherein the inertial force sensitive module senses acceleration and converts the acceleration into inertial force applied to the two groups of frequency modulation modules, and the loading direction of the inertial force is perpendicular to the vibration direction of the two groups of frequency modulation modules; the frequency modulation module forms an alternating thermal expansion force through a closed loop therein, and completes the self-excited oscillation of the frequency modulation module under the action of the alternating thermal expansion force.

[0008] A further technical solution of the present invention is: the inertial force sensitive module includes a mass block and levers connected to both sides thereof, the mass block is connected to a corresponding number of anchor points through multiple elastic beams for sensing acceleration; guide beams are respectively installed in the vertical direction of the levers on both sides, and the acceleration is converted into inertial force applied to the frequency modulation modules on both sides through the guide beams on both sides.

[0009] A further technical solution of the present invention is: the mass block is a rectangular flat plate structure, and two groups of notched grooves are symmetrically arranged on the opposite sides where the levers are not installed. Anchor points are arranged at the outer ends of the notched grooves, and each anchor point is connected to the inner end of each notched groove by an elastic beam to form a working plane for acceleration detection.

[0010] A further technical solution of the present invention is: the frequency modulation module includes a nanobeam and a resonance plate symmetrically arranged at both ends thereof, and the outer ends of the resonance plate are respectively connected to anchor points through small stiffness beams; the midpoint of the nanobeam in the length direction is fixedly connected to the guide beam.

[0011] A further technical solution of the present invention is: the nanobeam is a straight beam or an arc beam. When the nanobeam is a straight beam, the starting axis is perpendicular to the guide beam axis; when the nanobeam is an arc beam, the tangent of the connection point between it and the guide beam is perpendicular to the guide beam axis, and the tangent of the two end points of the arc beam forms an angle of 45 degrees with the connecting edge of the resonant plate.

[0012] A further technical solution of the present invention is: the resonant plate is a square structure, one side of which is connected to the nano-beam, and two vertices of the opposite side are respectively connected to small-rigidity beams.

[0013] A further technical solution of the present invention is: the length-to-width ratio of the small-rigidity beam is 20:1, and the side length of the resonant plate is 3 times the length of the small-rigidity beam.

[0014] A further technical solution of the present invention is that the closed loop in the frequency modulation module is composed of a nanobeam and a resonance plate, that is, a self-excited oscillation module.

[0015] A further technical solution of the present invention is: the self-excited oscillation method of the self-excited oscillation module is:

[0016] Injecting current into the nanobeam increases its temperature, and thermal expansion causes the nanobeam strain to increase;

[0017] Based on the silicon material property that the nanobeam has a negative piezoresistance coefficient, thermal expansion causes the piezoresistance coefficient to decrease, resulting in a decrease in the resistance of the nanobeam, which in turn causes its temperature to drop, and the nanobeam begins to thermally contract, resulting in a decrease in strain;

[0018] This cycle repeats itself, forming an alternating thermal expansion force;

[0019] Under the action of the alternating thermal expansion force, the frequency modulation module vibrates with a stable amplitude after being started.

[0020] A method for detecting acceleration of a thermal piezoresistive resonant accelerometer in an axial expansion mode, the specific steps are as follows:

[0021] An electrode is connected to the nanobeam of the frequency modulation module, and the nanobeam vibrates under the action of a DC bias signal of the driving electrode;

[0022] The mass block of the inertial force sensitive module senses the acceleration change and generates inertial force;

[0023] The generated inertial force is converted into a vertical inertial force applied to the frequency modulation module through the lever and guide beam of the inertial force sensitive module, that is, acting on the nanobeam, causing its stiffness to change;

[0024] The detection electrode outputs an AC current signal containing the amplitude information of the two frequency modulation modules. After the current signal is processed by the circuit, two voltage signals proportional to the amplitude of the frequency modulation module are output;

[0025] The change in the acceleration signal of the mass block is obtained by detecting the change in the ratio of the above two voltage signals.

[0026] Beneficial Effects

[0027] The beneficial effects of the present invention are as follows: the present invention proposes a novel heat-driven piezoresistive detection accelerometer structural design, which is composed of two parts with symmetrical characteristic structures as a whole, and can realize the structural differential function; its working principle adopts the traveling wave mode, and utilizes its required structural symmetry and simple geometric relationship and other characteristics to avoid the signal sensitivity attenuation caused by structural or process errors; the design constructs the whole into a resonator by coupling the nanobeam with the resonant plate and the small stiffness beam, and then vertical stress loading is performed by guiding the beam, thereby inventing an accelerometer that uses the lateral vibration mode of the resonator to detect acceleration, avoiding the interference of the lateral vibration of the resonator on the overall mode of the accelerometer, and filling the vacancy of this modal accelerometer.

[0028] The present invention is a nanomechanical acceleration sensor sensitive element based on the principle of thermal excitation piezoresistive detection (thermal piezoresistive), which uses the heat generated by the bias current to compensate for the vibration loss of the resonator, and forms a self-feedback loop through the negative piezoresistive effect, thereby abandoning the complex control circuit. In this way, electrical energy can be more efficiently converted into kinetic energy of the sensor sensitive element. In addition, by adjusting the stiffness of the nanomechanical thermal piezoresistive resonator through inertial force, inertial force perception based on frequency modulation output can be achieved. This new sensor can not only improve the performance of the sensor, but also is expected to reduce its power consumption, thereby extending battery life and broadening its scope of use in various application fields.

[0029] The experiment verified that the theoretical magnification of the lever is 10 times and the cross sensitivity of the spring beam is 0.15%. The simulation results show that the sensitivity of the structure is 3Hz / g. Figure 4 As shown in Figure 2, the performance of the nanobeam is improved by an order of magnitude compared to other accelerometers in this transverse vibration mode because the transverse compression stiffness of the nanobeam is converted into longitudinal bending stiffness. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the structure in the embodiment of the present invention; (a) is a top view of the structure; (b) is a partial enlarged view of the straight beam; (c) is a partial enlarged view of the "C"-shaped beam; (d) is a three-dimensional schematic diagram of the structure;

[0031] Figure 2 Schematic diagram of the self-oscillation principle in an embodiment of the present invention;

[0032] Figure 3 is a schematic diagram of working modes in an embodiment of the present invention;

[0033] Figure 4 It is a sensitivity simulation diagram in an embodiment of the present invention;

[0034] Explanation of the accompanying drawings: 1-1 is the first spring beam, 1-2 is the second spring beam, 1-3 is the third spring beam, 1-4 is the fourth spring beam; 2 is a mass block; 3-1 is the first lever, 3-2 is the second lever; 4-1 is the first guide beam, 4-2 is the second guide beam; 5-1 is the first nanobeam, 5-2 is the second nanobeam; 6-1 is the first resonant plate, 6-2 is the second resonant plate, 6-3 is the third resonant plate, 6-4 is the fourth resonant plate; 7-1 is the first small stiffness beam, 7-2 is the second small stiffness beam, 7-3 is the third small stiffness beam, 7-4 is the fourth small stiffness beam, 7-5 is the fifth small stiffness beam, 7-6 is the sixth small stiffness beam, 7-7 is the seventh small stiffness beam, 7-8 is the eighth small stiffness beam; 8 is an anchor point. DETAILED DESCRIPTION

[0035] The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0036] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0037] The present invention aims to get rid of the limitation of sensor power consumption by electronic circuit system, and intends to study the sensitive element of nanomechanical acceleration sensor based on the principle of thermal excitation piezoresistive detection (thermal piezoresistive): using the heat generated by bias current to compensate the vibration loss of resonator, combining with negative piezoresistive effect to form a self-feedback loop, thereby eliminating complex control circuits and converting electrical energy into kinetic energy of sensor sensitive element more efficiently; adjusting the stiffness of resonator by inertial force, realizing inertial force perception based on frequency modulation output. The vibration of resonator is different from the bending vibration of traditional resonator, and belongs to the axial expansion vibration of nanobeam.

[0038] The above technical solution is further described below with reference to the accompanying drawings and examples:

[0039] In one embodiment, a thermal piezoresistive resonant accelerometer with an axial expansion mode includes: an inertial force sensitive module and two groups of frequency modulation modules symmetrically connected at both ends thereof, wherein the inertial force sensitive module senses acceleration and converts the acceleration into inertial force applied to the two groups of frequency modulation modules, and the loading direction of the inertial force is perpendicular to the vibration direction of the two groups of frequency modulation modules; the frequency modulation module forms an alternating thermal expansion force through a closed loop therein, and completes self-excited oscillation of the frequency modulation module under the action of the alternating thermal expansion force.

[0040] In one embodiment, the inertial force sensitive module includes a mass block and levers connected to both sides thereof, wherein the mass block is connected to a corresponding number of anchor points through a plurality of elastic beams for sensing acceleration; guide beams are respectively installed in the vertical direction of the levers on both sides, and the acceleration is converted into inertial force applied to the frequency modulation modules on both sides through the guide beams on both sides.

[0041] Preferably, the mass block is a rectangular flat plate structure, and two groups of notched grooves are symmetrically arranged on the two opposite sides where the lever is not installed. Anchor points are arranged at the outer ends of the notched grooves, and each anchor point is connected to the inner end of each notched groove by an elastic beam to form a working plane for acceleration detection.

[0042] In one embodiment, the frequency modulation module includes a nanobeam and resonance plates symmetrically arranged at both ends thereof, and the outer ends of the resonance plate are respectively connected to anchor points through small stiffness beams; the midpoint of the nanobeam in the length direction is fixedly connected to the guide beam.

[0043] Preferably, the nanobeam is a straight beam or an arc beam. When the nanobeam is a straight beam, its axis is perpendicular to the axis of the guide beam; when the nanobeam is an arc beam, the tangent of the connection point between it and the guide beam is perpendicular to the axis of the guide beam, and the tangent of the two end points of the arc beam forms an angle of 45 degrees with the connecting edge of the resonant plate.

[0044] Preferably, the resonant plate is a square structure, one side of which is connected to the nanobeam, and two vertices of the opposite side are respectively connected to small-rigidity beams.

[0045] Preferably, the aspect ratio of the low-rigidity beam is 20:1, and the side length of the resonance plate is 3 times the length of the low-rigidity beam.

[0046] In one embodiment, the closed loop in the frequency modulation module is composed of a nanobeam and a resonant plate, that is, a self-excited oscillation module.

[0047] In one embodiment, referring to Figure 1 As shown, a heat-driven piezoresistive detection accelerometer structure of this embodiment includes a mass block, a spring beam, a guide structure, a lever amplification mechanism, a resonance plate (side length is 3 times the length of the small stiffness beam), a nanobeam, and a small stiffness beam (length-to-width ratio is 20:1); the resonance plate, the nanobeam, and the small stiffness beam together constitute a resonator. The movement of the mass block is amplified by the lever amplification mechanism, and then vertically loaded to the nanobeam through the guide beam, thereby modulating the resonant frequency. The spring beam is used to suppress the influence of unnecessary interference on the accelerometer and reduce cross-sensitivity, and the resonance plate and the small stiffness beam are used to reduce the overall stiffness of the structure.

[0048] The above structure can be divided into an inertial force sensing module, a frequency modulation module, and a self-excited oscillation module according to the working mechanism.

[0049] In one embodiment, the inertial force sensitive module is composed of spring beams 1-1, 1-2, 1-3, 1-4; mass block 2; levers 3-1, 3-2; guide beams 4-1, 4-2, and its main function is to sense acceleration, and then convert the acceleration into a longitudinal force applied to the nanobeam through a lever amplification structure ( Figure 1a vertical direction). The frequency modulation module is composed of nano-beams 5-1, 5-2; resonant plates 6-1, 6-2, 6-3, 6-4; and small stiffness beams 7-1, 7-2, 7-3, 7-4, 7-5, 7-6, 7-7, 7-8, which are mainly responsible for bearing the stress transmitted by the inertial force sensitive module, thereby changing the effective stiffness and realizing frequency modulation. The self-excited oscillation module is composed of thermal piezoresistive resonators 5-1, 5-2 and resonant plates 6-1, 6-2, 6-3, 6-4, wherein the nano-beams and the resonant plates form a closed loop, and realize self-excited oscillation under the action of alternating thermal expansion force. In the present invention, the thermal piezoresistive resonator is designed with two structures: a straight beam and a "C"-shaped beam. The "C"-shaped beam structure is to further reduce the stiffness of the resonator and improve the sensitivity; the role of the resonant plate structure is to reduce its resistance and overall structural stiffness, so that the electrical energy in the loop is more efficiently converted into the kinetic energy of the thermal piezoresistive resonator, further reducing the power consumption of the sensor.

[0050] Since the overall structure involved in the present invention is composed of two parts with symmetrical characteristics, half of the part is taken as an example when explaining its basic working principle. The specific working process is as follows:

[0051] Thermally actuated piezoresistive sensing is a sensing technology that combines thermal, electrical, and mechanical energy. Figure 2 As shown: Its working principle involves the self-excited oscillation of the resonator, which is first started by injecting a direct current. When the current flows through the nanobeam, it causes the temperature to rise, which in turn causes the nanobeam to thermally expand, which increases the strain of the nanobeam. Since the nanobeam is made of silicon material with a negative piezoresistance coefficient, thermal expansion causes the piezoresistance coefficient to decrease, thereby reducing the resistance value of the nanobeam, further causing the temperature to drop, causing the nanobeam to thermally contract and the strain to decrease. This process is repeated, forming an alternating thermal expansion force. Under the action of this force, the resonator can vibrate with a stable amplitude.

[0052] In one embodiment, the resonant detection method of inertial force is as follows: In this device, the nanobeam resonator vibrates laterally under the action of the DC bias signal of the driving electrode ( Figure 1 (b) horizontal direction). When the input acceleration changes, the inertial force generated by the mass block will act on the nanobeam, causing its stiffness to change. By detecting the electrodes, an AC current signal containing the amplitude information of the two resonators can be output. After being processed by the circuit, these current signals can be converted into voltage signals that are proportional to the resonator amplitude. Therefore, by monitoring the change in the ratio of these two voltage signals, the change in the acceleration signal of the mass block can be obtained.

[0053] In order to improve the sensitivity of the accelerometer, the present invention theoretically derives a specific expression of the sensitivity of the accelerometer. Taking the lower half as an example, the sensitivity of the accelerometer is given by the following formula:

[0054]

[0055] Among them, ρt m S m are respectively the density, thickness and area of ​​the mass block; S r is the cross-sectional area of ​​the resonator; k ff is the bending stiffness of the equivalent flexible spring beam; k rc is the resonator compression stiffness, ω 0r is the resonant frequency of the resonator; σ buck is the resonator yield limit.

[0056] From the above formula, we can know that the accelerometer sensitivity S aω It has a certain relationship with many parameters, and the changes in these parameters will have an impact on the sensitivity. Therefore, analyzing the impact trend of these parameters on the sensitivity of the accelerometer is of great value for subsequently breaking through the accuracy limit of existing MEMS accelerometers.

[0057] Reference Figure 1 As shown, the substrate material used by the chip-level thermally driven piezoresistive detection resonant accelerometer in this embodiment is single crystal silicon, that is, from top to bottom, it is single crystal silicon layer-silicon dioxide crystal layer-single crystal silicon layer, and the acceleration structure placed on the upper surface of the substrate includes three parts: an inertial force sensitive module, a frequency modulation module, and a self-excited oscillation module. The self-excited oscillation module is formed by etching and sputtering metal on the surface of the uppermost single crystal silicon layer, and the inertial force sensitive module and the frequency modulation module are realized by etching on the surface of the uppermost single crystal silicon layer.

[0058] Preferably, the thickness of the topmost layer of single crystal silicon is 10 μm; in the inertial force sensitive module, the area of ​​the mass block is 2000 μm×2000 μm; the spring beams 1-1, 1-2, 1-3, and 1-4 are all composed of a 400 μm×4 μm slender beam and a 100 μm square anchor point; the length and width of the lever input beams 3-1 and 3-2 are 150 μm and 3 μm respectively; the length and width of the lever arm are 870 μm and 30 μm respectively; the length and width of the output beam are 40 μm and 3 μm respectively; the length and width of the support beam are 15 μm and 3 μm respectively; the guide beams 4-1 and 4-2 are composed of It consists of a long beam and a short beam, in which the long beam has a length and width of 400μm and 20μm respectively; the short beam has a length and width of 20μm and 2μm respectively; the four square resonant plates 6-1, 6-2, 6-3, and 6-4 in the frequency modulation module have a side length of 300μm; the small stiffness beams 7-1, 7-2, 7-3, 7-4, 7-5, 7-6, 7-7, and 7-8 have a length and width of 100μm and 5μm respectively; the straight beams of 5-1 and 5-2 thermal piezoresistive resonators in the self-excited oscillation module have a length and width of 60μm and 2μm respectively, and the tangential angle of the "C"-shaped beam is 45° and the width is 2μm.

[0059] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and intent of the present invention.

Claims

1. A thermal piezoresistive resonant accelerometer in axial expansion mode, characterized in that: The invention comprises an inertial force sensitive module and two groups of frequency modulation modules symmetrically connected at both ends thereof. The inertial force sensitive module senses acceleration and converts the acceleration into inertial force applied to the two groups of frequency modulation modules. The loading direction of the inertial force is perpendicular to the vibration direction of the two groups of frequency modulation modules. The frequency modulation module forms an alternating thermal expansion force through a closed loop therein, and completes the self-excited oscillation of the frequency modulation module under the action of the alternating thermal expansion force.

2. The axial expansion mode thermal piezoresistive resonant accelerometer according to claim 1, characterized in that: The inertial force sensitive module includes a mass block and levers connected to both sides thereof. The mass block is connected to a corresponding number of anchor points through multiple elastic beams for sensing acceleration. Guide beams are installed in the vertical direction of the levers on both sides, and the acceleration is converted into inertial force applied to the frequency modulation modules on both sides through the guide beams on both sides.

3. The axial expansion mode thermal piezoresistive resonant accelerometer according to claim 2, characterized in that: The mass block is a rectangular flat plate structure, and two groups of notched grooves are symmetrically arranged on the opposite sides where the lever is not installed. Anchor points are arranged at the outer ends of the notched grooves, and each anchor point is connected to the inner end of each notched groove by an elastic beam to form a working plane for acceleration detection.

4. The axial expansion mode thermal piezoresistive resonant accelerometer according to claim 2, characterized in that: The frequency modulation module includes a nanobeam and resonance plates symmetrically arranged at both ends thereof, and both ends of the outer side of the resonance plate are respectively connected to anchor points through small stiffness beams; the midpoint of the nanobeam in the length direction is fixedly connected to the guide beam.

5. The axial expansion mode thermal piezoresistive resonant accelerometer according to claim 4, characterized in that: The nanobeam is a straight beam or an arc beam. When the nanobeam is a straight beam, its axis is perpendicular to the axis of the guide beam; when the nanobeam is an arc beam, the tangent of the connection point between it and the guide beam is perpendicular to the axis of the guide beam, and the tangent of the two end points of the arc beam forms an angle of 45 degrees with the connecting edge of the resonant plate.

6. The axial expansion mode thermal piezoresistive resonant accelerometer according to claim 5, characterized in that: The resonant plate is a square structure, one side of which is connected to the nano-beam, and two vertices of the opposite side are respectively connected to small-rigidity beams.

7. The axial expansion mode thermal piezoresistive resonant accelerometer according to claim 6, characterized in that: The length-to-width ratio of the low-rigidity beam is 20:1, and the side length of the resonance plate is 3 times the length of the low-rigidity beam.

8. The axial expansion mode thermal piezoresistive resonant accelerometer according to claim 1, characterized in that: The closed loop in the frequency modulation module is composed of a nanobeam and a resonance plate, that is, a self-excited oscillation module.

9. The axial expansion mode thermal piezoresistive resonant accelerometer according to claim 8, characterized in that: The self-excited oscillation method of the self-excited oscillation module is: Injecting current into the nanobeam increases its temperature, and thermal expansion causes the nanobeam strain to increase; Based on the silicon material property that the nanobeam has a negative piezoresistance coefficient, thermal expansion causes the piezoresistance coefficient to decrease, resulting in a decrease in the resistance of the nanobeam, which in turn causes its temperature to drop, and the nanobeam begins to thermally contract, resulting in a decrease in strain. This cycle repeats itself, forming an alternating thermal expansion force; Under the action of the alternating thermal expansion force, the frequency modulation module vibrates with a stable amplitude after being started.

10. An acceleration detection method of the axial expansion mode thermal piezoresistive resonant accelerometer according to any one of claims 1 to 9, characterized in that The specific steps are as follows: An electrode is connected to the nanobeam of the frequency modulation module, and the nanobeam vibrates under the action of a DC bias signal of the driving electrode; The mass block of the inertial force sensitive module senses the acceleration change and generates inertial force; The generated inertial force is converted into a vertical inertial force applied to the frequency modulation module through the lever and guide beam of the inertial force sensitive module, that is, acting on the nanobeam, causing its stiffness to change; The detection electrode outputs an AC current signal containing the amplitude information of the two frequency modulation modules. After the current signal is processed by the circuit, two voltage signals proportional to the amplitude of the frequency modulation module are output; The change in the acceleration signal of the mass block is obtained by detecting the change in the ratio of the above two voltage signals.

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