Silicon Micro Gyroscope

Abstract

The present invention provides a silicon micro gyroscope, belonging to the technical field of inertial angular velocity detection, comprising a substrate, a mass unit, a driving unit and a detection unit; the mass unit comprises two groups of mass modules, the two groups of mass modules are connected by a first elastic coupling beam, the first elastic module connects the mass module to the substrate; the driving unit comprises a plurality of driving modules arranged around the periphery of the mass unit, the second elastic module fixes the driving module to the substrate, the driving module is used to receive an external input electrical signal, the driving module moves along the X-axis, and drives the mass module to perform torsional simple harmonic motion along the Y-axis, when the external inertial angular velocity around the X-axis is input, the mass module will perform rotational motion with the Y-axis as the rotation axis; the detection unit is arranged between the mass unit and the substrate. The silicon micro gyroscope provided by the present invention aims to solve the problem that the common mode interference signal suppression capability of the silicon micro gyroscope in the prior art is poor, the detection sensitivity and signal-to-noise ratio are low, resulting in low overall detection accuracy.

Description

Technical Field

[0001] The invention belongs to the technical field of inertial angular velocity detection, and more specifically, relates to a silicon micro-gyroscope. Background Art

[0002] Silicon micro gyroscope is a MEMS inertial sensor that measures the angular velocity of rotation. This sensor uses MEMS processing technology and has the advantages of miniaturization, low cost, high integration, high reliability and mass production. It is widely used in aerospace, automotive navigation, industrial control and consumer electronics, and has broad application prospects and application value.

[0003] Silicon micro-gyroscopes are usually combined with micro-accelerometers in small inertial measurement units (IMUs). Since traditional silicon micro-gyroscopes are generally Z-axis gyroscopes used for yaw angular rate detection, if the IMU wants to achieve simultaneous detection of pitch angular rate and roll angular rate, the Z-axis gyroscope needs to be placed vertically. This placement method increases the volume of the inertial measurement unit, which is not conducive to the miniaturization of the micro-inertial system. In addition, most of the existing silicon micro-gyroscopes generally have problems such as low detection sensitivity, poor signal-to-noise ratio of detection signals, and poor ability to suppress common-mode interference signals. Summary of the invention

[0004] The purpose of the present invention is to provide a silicon micro-gyroscope, aiming to solve the problem that the silicon micro-gyroscope in the prior art has poor common-mode interference signal suppression capability, low detection sensitivity and signal-to-noise ratio, resulting in low overall detection accuracy.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A silicon micro gyroscope is provided, comprising:

[0007] substrate;

[0008] The mass unit comprises two groups of mass modules sequentially distributed along the X axis, the two groups of mass modules are connected by a first elastic coupling beam, the central area of ​​the mass module has a hollow installation area, the installation area is provided with a first elastic module, and the first elastic module connects the mass module to the substrate;

[0009] A driving unit, comprising a plurality of driving modules arranged around the periphery of the mass unit, two adjacent driving modules being connected by a second elastic module, the second elastic module fixing the driving module to the substrate, the driving module being used to receive an external electrical signal, the driving module moving along the X-axis under the action of electrostatic force, and driving the mass module to perform torsional simple harmonic motion along the Y-axis, the torsion directions of the two groups of mass modules being opposite, when the mass module performs torsional simple harmonic motion along the Y-axis, when there is an inertial angular velocity input around the X-axis from the outside, the mass module will perform rotational motion with the Y-axis as the rotation axis under the action of the Coriolis force; and

[0010] The detection unit is disposed between the mass unit and the substrate and connected to the substrate. The detection unit is used to detect the angular velocity of the mass module on the X-axis and convert it into an electrical signal for output.

[0011] In a possible implementation, the mass module includes two mass blocks spaced apart along the X-axis, the two mass blocks are connected by a connecting arm, and the first elastic module is located on one side of the connecting arm along the Y-axis and is respectively connected to the two mass blocks.

[0012] In a possible implementation, the driving module is connected to the corresponding mass module along the Y-axis via a second elastic coupling beam.

[0013] In a possible implementation, the first elastic module includes:

[0014] A first elastic member, comprising an elastic frame and a first elastic beam disposed in the elastic frame, wherein the elastic frame is connected to the mass module; and

[0015] A first fixing anchor point is connected to the first elastic beam and is used to fix the first elastic beam to the substrate.

[0016] In a possible implementation, the driving modules are provided in two groups with the Y axis as the symmetry axis, and each group of the driving modules includes two groups of driving modules that are mirror-symmetrically arranged with the X axis as the symmetry axis, and the two groups of driving modules are connected by a third elastic module.

[0017] In a possible implementation, the driving module includes:

[0018] A driving frame having a plurality of driving zones, wherein the plurality of driving zones are distributed along the X-axis and / or the Y-axis; and

[0019] A plurality of driving comb teeth are arranged corresponding to the driving areas one by one. The driving comb teeth are arranged in the driving areas and connected to the driving frame.

[0020] The beneficial effect of the silicon micro-gyroscope provided by the present invention is that: compared with the prior art, the central part of each mass module in the silicon micro-gyroscope of the present invention is connected to the substrate through the first elastic module, and the driving unit is arranged around the periphery of the mass unit and connected to the substrate through the second elastic module. When an excitation voltage signal is applied to the driving module, under the action of electrostatic force, the two groups of driving modules move in opposite directions along the X-axis, so that the two groups of mass modules take the first elastic module as the base point and perform torsional simple harmonic motion along the Y-axis, and the torsional directions of the two groups of mass modules are opposite. When the mass module performs torsional simple harmonic motion along the Y-axis, if there is an inertial angular velocity input around the X-axis from the outside, the mass module will generate a detection displacement along the Z-axis under the action of the Coriolis force, and the mass module rotates with the first elastic module (Y-axis) as the rotation axis, and the rotation directions of the two groups of mass modules are opposite, so as to detect the angular velocity of the X-axis. The driving module is arranged around the periphery of the mass unit, so that the mass unit is distributed with driving modules on both the X-axis and the Y-axis, and more driving electrodes can be arranged to generate a stronger driving force. The increase in driving force can generate a greater detection sensitivity, thereby improving the detection accuracy. The center of the mass module of the present invention is provided with a first elastic module, and the two groups of driving modules are connected by a second elastic module, which can effectively suppress the interference modal frequency of the mass module during the detection movement and the driving movement, enhance the coupling between the components, and improve the consistency of the overall structure, thereby improving the detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, 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 only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 A top view of a silicon micro-gyroscope provided by an embodiment of the present invention;

[0023] Figure 2 It is a side view of the detection unit, substrate and mass block used in the embodiment of the present invention, wherein: Figure 2 (a) is the state diagram of the mass block when there is no angular velocity input. Figure 2 (b) The state diagram of the mass block when there is angular velocity input;

[0024] Figure 3 A driving mode diagram of a silicon micro gyroscope provided by an embodiment of the present invention;

[0025] Figure 4 A detection mode diagram of the silicon micro-gyroscope provided in an embodiment of the present invention.

[0026] In the figure: 1. driving unit; 101. driving frame; 102. driving comb teeth; 103. second elastic module; 1031. second elastic beam; 1032. second fixed anchor point; 104. third elastic module; 1041. third elastic beam; 1042. third fixed anchor point; 2. mass unit; 201. mass module; 2011. mass block; 2012. connecting arm; 202. first elastic module; 2021. elastic frame; 2022. first elastic beam; 2023. first fixed anchor point; 203. first elastic coupling beam; 204. second elastic coupling beam; 3. substrate; 4. detection unit. DETAILED DESCRIPTION

[0027] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0028] In the claims, specification and the above drawings of the present invention, unless otherwise clearly defined, the terms "first", "second" or "third" are used to distinguish different objects, rather than to describe a specific order. Unless otherwise specified, other directional words, such as "vertical", "clockwise", "counterclockwise", etc., indicating directions or positional relationships are based on the directions and positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, so it cannot be understood as limiting the specific protection scope of the present invention. In the claims, specification and the above drawings of the present invention, unless otherwise clearly defined, the terms "fixed connection" or "fixed connection" should be understood in a broad sense, that is, any connection method without a displacement relationship and relative rotation relationship between the two, that is, including non-detachable fixed connection, detachable fixed connection, integrated connection and fixed connection through other devices or elements. In the claims, specification and the above drawings of the present invention, the terms "including", "having" and their variations are used, and the intention is to "include but not limited to".

[0029] Please also read Figures 1 to 4The silicon micro gyroscope provided by the present invention is now described. The silicon micro gyroscope includes a substrate 3, a mass unit 2, a drive unit 1 and a detection unit 4; the mass unit 2 includes two groups of mass modules 201 distributed in sequence along the X axis, the two groups of mass modules 201 are connected by a first elastic coupling beam 203, the central area of ​​the mass module 201 has a hollow installation area, the installation area is provided with a first elastic module 202, the first elastic module 202 connects the mass module 201 to the substrate 3; the drive unit 1 includes a plurality of drive modules arranged around the periphery of the mass unit 2, two adjacent groups of drive modules are connected by a second elastic module 103, the second elastic module 103 connects the drive modules The two groups of mass modules 201 are fixed to the substrate 3, the driving module is used to receive the external input electrical signal, and under the action of the electrostatic force, the driving module moves along the X-axis, and drives the mass module 201 to perform torsional simple harmonic motion along the Y-axis. The torsion directions of the two groups of mass modules 201 are opposite. When the mass module 201 performs torsional simple harmonic motion along the Y-axis, when the external inertial angular velocity around the X-axis is input, the mass module 201 will perform rotational motion with the Y-axis as the rotation axis under the action of the Coriolis force; the detection unit 4 is arranged between the mass unit 2 and the substrate 3, and is connected to the substrate 3. The detection unit 4 is used to detect the angular velocity of the mass module 201 on the X-axis and convert it into an electrical signal for output.

[0030] Compared with the prior art, the silicon micro-gyroscope provided by the present invention has a central portion of each mass module 201 connected to the substrate 3 through the first elastic module 202, and the driving unit 1 is arranged around the periphery of the mass unit 2 and connected to the substrate 3 through the second elastic module 103. When an excitation voltage signal is applied to the driving module, the two groups of driving modules move in opposite directions along the X-axis under the action of electrostatic force, so that the two groups of mass modules 201 perform torsional simple harmonic motion along the Y-axis with the first elastic module 202 as the base point ( Figure 3 ), and the torsion directions of the two mass modules 201 are opposite. When the mass module 201 performs torsional simple harmonic motion along the Y axis, if there is an inertial angular velocity input around the X axis from the outside, the mass module 201 will generate a detection displacement along the Z axis under the action of the Coriolis force, and the mass module 201 rotates with the first elastic module 202 (Y axis) as the rotation axis, and the rotation directions of the two mass modules 201 are opposite (please refer to Figure 4 ), thereby detecting the angular velocity of the X-axis. The driving module is arranged around the periphery of the mass unit 2, so that the mass unit 2 is distributed with driving modules on both the X-axis and the Y-axis, and more driving electrodes can be arranged to generate a stronger driving force. The increase in driving force can generate a greater detection sensitivity, thereby improving the detection accuracy. The center of the mass module 201 of the present invention is provided with a first elastic module 202, and the two groups of driving modules are connected by a second elastic module 103, which can effectively suppress the interference modal frequency of the mass module 201 during the detection movement and the driving movement, enhance the coupling between the components, improve the consistency of the overall structure, and thus improve the detection accuracy.

[0031] Optionally, the second elastic module 103 includes a second elastic beam 1031 and a second fixing anchor point 1032 connected to the second elastic beam 1031 .

[0032] It should be noted that the vibrating silicon micro-gyroscope uses the Coriolis effect to sense external angular velocity signals. The detection mass of the gyroscope is connected to the substrate 3 through an elastic beam. When working, it performs simple harmonic vibration along the driving direction under the action of the electrostatic driving force. When an angular velocity signal is input in the sensitive axis, a Coriolis force will be generated in a direction orthogonal to both the vibration direction and the angular velocity direction. The detection mass will be displaced under the action of the Coriolis force, and the detection electrode (i.e. Figure 2 The detection unit in the detection electrode forms a flat capacitor between the detection electrode and the mass block. When the mass block is acted upon by the Coriolis force, it is displaced in the Z direction, causing the gap between the flat capacitors to change, resulting in one capacitor becoming larger and the other becoming smaller. The capacitance change can be obtained by differential analysis. The capacitance change is detected and processed by the subsequent ASIC to obtain the angular velocity value.

[0033] It should be noted that silicon micro-gyroscopes are usually used in combination with micro-accelerometers in small inertial measurement units (IMUs). Since traditional silicon micro-gyroscopes are generally Z-axis gyroscopes, which are used for yaw rate detection, if the IMU wants to achieve simultaneous detection of pitch rate and roll rate, the Z-axis gyroscope needs to be placed vertically. This placement method increases the volume of the inertial measurement unit, which is not conducive to the miniaturization of the micro-inertial system. Therefore, it is of great significance to design and develop X or Y axis gyroscopes that can directly measure pitch rate and roll rate.

[0034] In some embodiments, see Figure 1 The mass module 201 includes two mass blocks 2011 spaced apart along the X-axis, the two mass blocks 2011 are connected by a connecting arm 2012, and the first elastic module 202 is located on one side of the connecting arm 2012 along the Y-axis and is respectively connected to the two mass blocks 2011.

[0035] In this embodiment, each mass module 201 is formed by two mass blocks 2011, that is, the mass unit 2 includes four mass blocks 2011, forming two sets of differential detection signals. Compared with the dual-mass angular velocity micromechanical detection structure used in the prior art, the signal generated by the four mass blocks 2011 is larger. By detecting the differential signal, while effectively suppressing the common-mode interference signal, the detection sensitivity and signal-to-noise ratio can be significantly improved, the common-mode interference signal can be better suppressed, and the detection accuracy can be improved. In addition, the two mass blocks 2011 located in the same mass module 201 are connected and fixed by the connecting arm 2012 to realize the linkage of the mass module 201.

[0036] Optionally, there is one connecting arm 2012 , or multiple (preferably two) connecting arms 2012 are spaced apart along the Y axis. When there are multiple connecting arms 2012 , the first elastic module 202 is disposed between two adjacent connecting arms 2012 .

[0037] In some embodiments, see Figure 1 The driving module is connected to the corresponding mass module 201 along the Y-axis through the second elastic coupling beam 204.

[0038] Each mass module 201 is connected to a driving module, and when the two driving modules have opposite driving forces, the two groups of mass modules 201 twist in opposite directions along the Y axis. In this embodiment, the mass module 201 and the driving module are connected through the second elastic coupling beam 204, which can increase the connection reliability between the mass module 201 and the driving module and transmit the movement of the driving module to the mass module 201.

[0039] Optionally, in this embodiment, the second elastic coupling beam 204 is coaxially arranged with a fixing point of the first elastic module 202 .

[0040] In some embodiments, see Figure 1 The first elastic module 202 includes a first elastic member and a first fixed anchor point 2023. The first elastic member includes an elastic frame 2021 and a first elastic beam 2022 arranged in the elastic frame 2021. The elastic frame 2021 is connected to the mass module 201; the first fixed anchor point 2023 is connected to the first elastic beam 2022, and is used to fix the first elastic beam 2022 to the substrate 3.

[0041] The elastic frame 2021 is connected to the mass module 201, and has better deformation resistance and stability than the strip structure. It can suppress the interference modal frequency of the detection movement and the driving movement, enhance the coupling between the various components of the structure, and improve the overall structural consistency.

[0042] In some embodiments, see Figure 1 The driving modules are provided with two groups with the Y axis as the symmetry axis, and each group of driving modules includes two groups of driving modules which are arranged in mirror symmetry with the X axis as the symmetry axis, and the two groups of driving modules are connected by a third elastic module 104.

[0043] When an excitation voltage signal is applied to the driving module, the driving modules in the same group move in the opposite direction, and the two driving modules in the same driving module also move in the opposite direction, so that the mass module 201 performs torsional simple harmonic motion along the Y axis. The scheme in this embodiment is to achieve the reverse movement of the two groups of mass modules 201 with the minimum number of driving modules, and the driving module can also be composed of a larger number of driving modules, which can be adjusted according to actual conditions.

[0044] Optionally, the third elastic module 104 includes a third elastic beam 1041 and a third fixing anchor point 1042. The third fixing anchor point 1042 may be located at a free end of the third elastic beam 1041.

[0045] In some embodiments, see Figure 1 The driving module includes a driving frame 101 and a plurality of driving comb teeth 102 . The driving frame 101 has a plurality of driving areas along the X-axis and the Y-axis respectively. The plurality of driving comb teeth 102 are arranged in one-to-one correspondence with the driving areas. The driving comb teeth 102 are arranged in the driving areas and connected to the driving frame 101 .

[0046] In the present embodiment, the driving frame 101 is arranged around the periphery of the mass unit 2, so that the number of driving comb teeth 102 can be increased as much as possible. While improving the driving capability (the stronger the driving capability, the higher the detection sensitivity, and thus the overall detection accuracy), the overall strength of the driving module is increased, the structural deformation is reduced, and the motion component of the driving motion in the detection direction is reduced, thereby reducing the impact on the detection motion.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A silicon micro gyroscope, characterized in that: include: substrate; A mass unit, comprising two groups of mass modules sequentially distributed along the X-axis, the two groups of mass modules being connected by a first elastic coupling beam, the central area of ​​the mass module having a hollow installation area, the installation area being provided with a first elastic module, the first elastic module connecting the mass module to the substrate, the first elastic module being able to effectively suppress the interference modal frequency of the mass module during the detection motion and the driving motion; A driving unit, comprising a plurality of driving modules arranged around the periphery of the mass unit, two adjacent driving modules being connected by a second elastic module, the second elastic module fixing the driving module to the substrate and enhancing the coupling between the components, the driving module being used to receive an external input electrical signal, the driving module moving in the opposite direction along the X-axis under the action of electrostatic force, and driving the two mass modules to perform torsional simple harmonic motion along the Y-axis with the first elastic module as a base point, the torsion directions of the two mass modules being opposite, when the mass modules perform torsional simple harmonic motion along the Y-axis, when there is an inertial angular velocity input around the X-axis from the outside, the mass modules will perform rotational motion with the Y-axis as the rotation axis under the action of Coriolis force; and The detection unit is disposed between the mass unit and the substrate and connected to the substrate. The detection unit is used to detect the angular velocity of the mass module on the X-axis and convert it into an electrical signal for output.

2. The silicon microgyroscope according to claim 1, characterized in that: The mass module comprises two mass blocks spaced apart along the X-axis, the two mass blocks are connected via a connecting arm, and the first elastic module is located on one side of the connecting arm along the Y-axis and is respectively connected to the two mass blocks.

3. The silicon micro-gyroscope according to claim 1, characterized in that: The driving module is connected to the corresponding mass module along the Y-axis through a second elastic coupling beam.

4. The silicon microgyroscope according to claim 1, characterized in that: The first elastic module comprises: A first elastic member, comprising an elastic frame and a first elastic beam disposed in the elastic frame, wherein the elastic frame is connected to the mass module; and A first fixing anchor point is connected to the first elastic beam and is used to fix the first elastic beam to the substrate.

5. The silicon micro-gyroscope according to claim 1, characterized in that: The driving modules are provided in two groups with the Y axis as the symmetry axis, and each group of the driving modules includes two groups of driving modules which are arranged in mirror symmetry with the X axis as the symmetry axis, and the two groups of the driving modules are connected by a third elastic module.

6. The silicon microgyroscope according to claim 1, characterized in that: The driving module comprises: A driving frame having a plurality of driving zones, wherein the plurality of driving zones are distributed along the X-axis and / or the Y-axis; and A plurality of driving comb teeth are arranged corresponding to the driving areas one by one. The driving comb teeth are arranged in the driving areas and connected to the driving frame.

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