MEMS gyroscopes

Abstract

The present invention provides a MEMS gyroscope, comprising a transducer, an anchor structure, a resonant ring, and a plurality of mass blocks disposed between the resonant ring and the anchor structure. The anchor structure and the mass blocks are connected by an elastic component capable of providing a restoring force to the mass blocks in the radial direction of the resonant ring. The mass blocks are connected to the resonant ring by a first elastic member capable of providing a restoring force to the resonant ring in the circumferential direction of the resonant ring, so that relative displacement between the resonant ring and the mass blocks occurs only in the circumferential direction. The mass blocks are circumferentially distributed about the center of the MEMS gyroscope, are rotationally symmetric about the center, and the number of the mass blocks is an integer multiple of 8. The transducers are circumferentially distributed about the center, are rotationally symmetric about the center, and the number of the transducers is an integer multiple of 8. The MEMS gyroscope of the present invention has a higher electromechanical coupling level, anti-interference capability, and sensitivity.

Description

Technical field

[0001] The present invention relates to the technical field of gyroscopes, and in particular to a MEMS gyroscope. [Background Technology]

[0002] A gyroscope is a sensor that measures the rotational motion of a carrier relative to inertial space. It is a core component in applications such as motion measurement, inertial navigation, and guidance and control.

[0003] A gyroscope manufactured using MEMS (Micro Electro Mechanical systems) technology is a MEMS (Micro Electro Mechanical systems) gyroscope, also known as a micromechanical gyroscope. Among them, the MEMS solid wave gyroscope is considered to have the highest potential for high performance. Its main types include MEMS multi-ring gyroscopes and micro-hemispherical resonant gyroscopes.

[0004] The MEMS multi-ring annular gyroscope is a typical example of a MEMS multi-ring annular gyroscope. Existing multi-ring annular gyroscopes consist of a central anchor point and a resonant ring disposed around the anchor point. In this structure, transducers are typically located only outside or on the resonant ring. This reduces the space available for transducers, reduces the electromechanical coupling of the gyroscope, and makes it difficult to improve its sensitivity. [Summary of the invention]

[0005] The purpose of the present invention is to provide a MEMS gyroscope, expand the distribution space of the transducer, improve the electromechanical coupling level of the gyroscope, and improve the sensitivity of the gyroscope.

[0006] The technical solutions of the present invention are as follows:

[0007] A MEMS gyroscope includes a transducer, an anchor structure, a resonant ring, and a plurality of mass blocks disposed between the resonant ring and the anchor structure. The anchor structure and the mass blocks are connected via an elastic component, the elastic component being capable of providing a restoring force for the mass blocks in a radial direction of the resonant ring. The mass blocks and the resonant ring are connected via a first elastic member, the first elastic member being capable of providing a restoring force for the resonant ring in a circumferential direction thereof, thereby causing relative displacement between the resonant ring and the mass blocks in the circumferential direction.

[0008] The mass blocks are distributed in a circle around the center of the MEMS gyroscope, and the mass blocks are rotationally symmetric about the center, and the number of the mass blocks is an integer multiple of 8;

[0009] The transducers are distributed in a circle about the center, and the transducers are rotationally symmetric about the center. The number of the transducers is an integer multiple of 8.

[0010] The beneficial effects of the present invention are:

[0011] By adding a mass block between the anchor structure and the resonant ring, the shape and volume of the single mass block are not constrained by the resonant ring structure, and the volume is larger and heavier, which can significantly improve the sensitivity of the gyroscope. It can also be integrally formed with the resonant ring and the anchor structure through etching, which simplifies the process and reduces production costs.

[0012] The addition of mass blocks allows transducers to be set on the mass blocks, between adjacent mass blocks, and between the mass blocks and the resonant ring, which expands the distribution space of the transducers, increases the transducer area, increases the number of transducers, reduces the driving voltage of the gyroscope, improves the electromechanical coupling level of the gyroscope, and improves the sensitivity of the gyroscope.

Brief Description of the Drawings

[0013] Figure 1 It is a structural diagram of a MEMS gyroscope according to a specific embodiment of the present invention.

[0014] Figure 2 yes Figure 1 Schematic diagram of a partial enlargement of the structure shown.

[0015] Figure 3 yes Figure 1 Schematic diagram of the force on the structure shown in the driving mode.

[0016] Figure 4 yes Figure 1 Schematic diagram of the force on the structure shown in the detection mode.

[0017] Figure 5 FIG. 4 is a structural diagram of a MEMS gyroscope according to another specific embodiment of the present invention. [Specific implementation method]

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0019] refer to Figures 1 to 5The present invention discloses a MEMS gyroscope, including a transducer, an anchor structure 10, a resonant ring 20, and a plurality of mass blocks 30 arranged between the resonant ring 20 and the anchor structure 10. The anchor structure 10 and the mass blocks 30 are connected by an elastic component 50, and the elastic component 50 can provide a restoring force for the mass blocks 30 along the radial direction of the resonant ring 20. The mass blocks 30 and the resonant ring 20 are connected by a first elastic member 60, and the first elastic member 60 can provide a restoring force for the resonant ring 20 along the circumferential direction of the resonant ring 20, so that only relative displacement occurs between the resonant ring 20 and the mass blocks 30 along the circumferential direction; the mass blocks 30 are distributed circumferentially about the center of the MEMS gyroscope, and the structure formed by all the mass blocks 30 is rotationally symmetric about the center of the MEMS gyroscope, and the number of the mass blocks 30 is an integer multiple of 8; the transducers are distributed circumferentially about the center of the MEMS gyroscope, and the transducers are rotationally symmetric about the center of the MEMS gyroscope, and the number of the transducers is also an integer multiple of 8. The present invention adds a mass block 30 to the resonant ring 20, and the mass block 30 is arranged between the anchor structure 10 and the resonant ring 20, so that the shape and volume of the single mass block 30 are not constrained by the structure of the resonant ring 20. The volume is larger and the mass is heavier, which can significantly improve the sensitivity of the gyroscope. It can also be integrally formed with the resonant ring 20 and the anchor structure 10 by etching, which simplifies the process and reduces production costs.

[0020] Rotational symmetry means that the structure obtained by rotating a certain angle around the center of the MEMS gyroscope can coincide with the initial structure.

[0021] The anchor structure 10, the resonant ring 20 and the mass block 30 are all located in the same plane. The transducer is used to realize the coupling of the mechanical field (including mechanical force and mechanical displacement) and the electric field of the MEMS gyroscope in the above plane. The form of the transducer can be, but is not limited to, one or a combination of two or more of capacitance, inductance, thermoelectricity, and piezoelectricity.

[0022] The transducer may include one, two, or more of the following: a first electrode assembly disposed on the side of the resonant ring 20 away from the mass 30; a second electrode assembly disposed on the resonant ring; a third electrode assembly disposed on the mass; a fourth electrode assembly disposed between adjacent mass blocks; and a fifth electrode assembly disposed between the mass block and the resonant ring. The addition of the mass 30 expands the distribution space for the transducers, increasing the transducer area, increasing the number of transducers, reducing the gyroscope's drive voltage, improving the gyroscope's electromechanical coupling, and enhancing the gyroscope's sensitivity.

[0023] refer to Figures 1 to 4 , the resonant ring 20 is located inside the mass block 30, and the anchor structure 10 is located outside the mass block 30. Figure 5 The resonant ring 20 may also be located outside the mass block 30 , and the anchor structure 10 may be located inside the mass block 30 .

[0024] In a specific embodiment, the mass 30 includes four first mass blocks located at azimuths of (i-1)*45°, i=1, 3, 5, 7, and four second mass blocks located at azimuths of (i-1)*45°, i=2, 4, 6, 8, respectively. The MEMS gyroscope of the present application includes a driving mode and a detection mode, referring to Figure 3 The driving mode is an elliptical mode with four antinodes and four nodes in which the resonant ring 20 vibrates in the first direction at an azimuth angle of 0° and in the second direction at an azimuth angle of 90°. At this time, the first mass block also undergoes radial displacement in the first and second directions. When the gyroscope resonating in the driving mode has an external angular velocity Ω input, the Coriolis effect causes the vibration energy of the driving mode of the resonant ring 20 to be transferred to the detection mode vibrating in the third direction at an azimuth angle of 45° and the fourth direction at an azimuth angle of 135°, thereby exciting the detection mode. Figure 4 This will cause the gyroscope's elliptical standing wave to precess. By measuring the precession angle θ, the gyroscope's external input angular velocity Ω can be obtained. At this time, the second mass will undergo radial displacement along the third and fourth directions.

[0025] In this specific embodiment, the number of first mass blocks should be an integer multiple of 4, that is, the number of first mass blocks is at least 4, the number of second mass blocks should be an integer multiple of 4, that is, the number of second mass blocks is at least 4, and the number of mass blocks 30 should be an integer multiple of 8, that is, the number of mass blocks 30 is at least 8.

[0026] Preferably, each mass block 30 should be distributed as much as possible in the space between the anchor structure 10 and the resonant ring 20 to increase the weight of the mass block as much as possible and improve the sensitivity.

[0027] Preferably, each mass block 30 is symmetrical about the center of the resonant ring 20 . The higher the symmetry, the more accurate the gyroscope.

[0028] refer to Figure 1 In one embodiment, the gyroscope also has an orthogonality suppression function. Specifically, mass block 30 further includes a third mass block located at an azimuth angle of 22.5° + (i-1) * 45°, where i = 1, 2, ..., 8. The third mass block can maintain the displacement of the first mass block in the first and second directions, suppressing the displacement of the first mass block from deviating from the first and second directions. The third mass block can also maintain the displacement of the second mass block in the third and fourth directions, suppressing the displacement of the second mass block from deviating from the third and fourth directions, thereby improving the calculation quality of angular velocity.

[0029] Improvement of detection accuracy and sensitivity depends on the stability of the structure. Figure 1 and Figure 2In a specific embodiment, the elastic component 50 includes a second elastic member 51 close to the anchor structure 10 and a third elastic member 52 close to the resonant ring 20. The second elastic member 51 and the third elastic member 52 are both fixed to the anchor structure 10. The second elastic member 51 and the third elastic member 52 respectively support the mass block 30 from both ends along the radial direction, thereby improving the stability of the mass block 30 and enhancing the precise control of the vibration of the mass block 30.

[0030] Furthermore, the number of second elastic members 51 is two, and the two second elastic members 51 are respectively located on both sides of one end of the mass block 30 close to the anchor structure 10; the number of third elastic members 52 is two, and the two third elastic members 52 are respectively located on both sides of one end of the mass block 30 close to the resonant ring 20. In this way, the second elastic member 51 and the third elastic member 52 respectively support the mass block from the four corners of the mass block 30, further improving the stability of the mass block 30, and can enhance the stiffness of the mass block 30 in the circumferential direction, so that the mass block 30 only undergoes displacement in the radial direction, thereby enhancing the control accuracy of the transducer.

[0031] Furthermore, the second elastic member 51 and the third elastic member 52 are both first comb-tooth springs extending in the radial direction. The width of the first comb-tooth spring in the circumferential direction is much greater than its thickness, thereby increasing the stiffness of the first comb-tooth spring in the circumferential direction and further ensuring that the mass block only displaces in the radial direction.

[0032] In order to fully utilize the space and improve the quality of the mass block 30 , the first comb-shaped spring is formed for the etched mass block.

[0033] In a specific embodiment, the first elastic member 60 is a second comb-shaped spring extending in the circumferential direction. The width of the second comb-shaped spring in the radial direction is much greater than its thickness, so as to ensure the rigidity of the first elastic member 60 in the radial direction, so that only relative displacement occurs along the circumferential direction between the resonant ring 20 and the mass block 30.

[0034] By using the first comb-shaped spring and the second comb-shaped spring for transmission, the driving vibration of the resonant ring 20 in the directions of 0° and 90° and the detection vibration in the directions of 45° and 135° can be made independent of each other, thereby achieving decoupling. The driving electrode can make the resonant ring 20 vibrate on the axis of maximum elliptical modal displacement, thereby improving the detection precision, accuracy and sensitivity, and increasing the degree of electromechanical coupling.

[0035] Preferably, the anchor structure 10 is an annular structure with a cavity inside.

[0036] Preferably, the shape of the side of the anchor structure 10 close to the mass block 30 is rotationally symmetric about the center of the gyroscope.

[0037] In this specific embodiment, the anchor structure 10, preferably near the mass 30, is annular, and the mass 30 is a sector ring. This structure achieves the highest symmetry and the highest gyroscope accuracy. In other embodiments, the anchor structure 10, also near the mass 30, can also have other rotationally symmetrical shapes. Accordingly, all masses 30 are arranged to form a rotationally symmetrical structure.

[0038] refer to Figure 1 and Figure 5 In a specific embodiment, the transducer may include a first electrode assembly arranged on a side of the resonant ring 20 away from the mass block 30. In a specific embodiment, the first electrode assembly may include four first electrodes SA respectively arranged at azimuth angles of (i-1)*45°, i=1, 3, 5, 7, four second electrodes SB respectively arranged at azimuth angles of (i-1)*45°, i=2, 4, 6, 8, and eight third electrodes QA respectively arranged at azimuth angles of 22.5°+(i-1)*45°, i=1, 2, …, 8. The first electrode SA and the first mass block are arranged opposite to each other, the second electrode SB and the second mass block are arranged opposite to each other, and the third electrode QA and the third mass block are arranged opposite to each other. At least one of the first electrodes SA is used to drive the vibration of the resonant ring 20, and at least one is used to detect the displacement of the resonant ring. At least one of the second electrodes SB is used to drive the vibration of the resonant ring 20, and at least one is used to detect the displacement of the resonant ring. At least one of the third electrodes QA is used to drive the vibration of the resonant ring 20, and at least one is used to detect the displacement of the resonant ring.

[0039] In other embodiments, a second electrode assembly may be provided on the resonant ring 20, a third electrode assembly may be provided on the mass block 30, a fourth electrode assembly may be provided between adjacent mass blocks 30, and a fifth electrode assembly may be provided between the mass block 30 and the resonant ring 20. Any combination of the first, second, third, fourth, and fifth electrode assemblies described above may be used, as long as they can drive and detect displacement of the resonant ring 20 in all directions. A greater number of electrodes increases the degree of electromechanical coupling and the control accuracy.

[0040] In one specific embodiment, capacitive electrodes can be provided on the first comb-shaped springs of the first and second masses. Capacitive drive is used to drive the first and second masses by controlling the spacing of the first comb-shaped springs. The comb-shaped springs can also increase the length of the capacitive drive, thereby increasing the gyroscope's drive capacitor area and reducing the gyroscope's drive voltage.

[0041] In a specific embodiment, the resonant ring 20 includes spokes and a plurality of coaxially spaced annular members, and any two adjacent annular members are connected by the spokes.

[0042] The technical solutions of the above specific embodiments can be used interchangeably.

[0043] The aforementioned MEMS gyroscope can operate in a force-balance mode. In the drive mode, the transducer drives the resonant ring 20 to vibrate in first and second directions. When the gyroscope rotates, the resonant ring 20 precesses, meaning its vibration direction deviates from the first and second directions. The transducer detects the deviation, or precession angle, and the control circuit drives the resonant ring 20 to vibrate in third and fourth directions based on the precession angle, thereby suppressing the precession of the resonant ring 20. The suppression target is to reduce the precession angle of the resonant ring 20 to zero. At this point, the control circuit's control variable can be used to convert the gyroscope's rotational angular velocity.

[0044] The MEMS gyroscope can also operate in full-angle mode. In the drive mode, the transducer drives the resonant ring 20 to vibrate in first and second directions. When the gyroscope rotates, the resonant ring 20 precesses. The transducer directly detects the precession angle and calculates the gyroscope's rotation angle based on the precession angle.

[0045] The above description is only an embodiment of the present invention. It should be pointed out that those skilled in the art can make improvements without departing from the creative concept of the present invention, but these improvements all fall within the scope of protection of the present invention.

Claims

1. A MEMS gyroscope, characterized in that: The invention comprises a transducer, an anchor structure, a resonant ring, and a plurality of mass blocks disposed between the resonant ring and the anchor structure, wherein the anchor structure and the mass blocks are connected via an elastic component, and the elastic component can provide a restoring force for the mass blocks along the radial direction of the resonant ring. The mass blocks and the resonant ring are connected via a first elastic member, and the first elastic member can provide a restoring force for the resonant ring along the circumferential direction of the resonant ring, so that a relative displacement occurs between the resonant ring and the mass blocks along the circumferential direction. The mass blocks are distributed in a circle around the center of the MEMS gyroscope, and the mass blocks are rotationally symmetric about the center, and the number of the mass blocks is an integer multiple of 8; The transducers are distributed in a circle about the center, and the transducers are rotationally symmetric about the center, and the number of the transducers is an integer multiple of 8; The resonant ring is located on the inner side of the mass block, and the anchor structure is located on the outer side of the mass block; the elastic component includes a second elastic member close to the anchor structure and a third elastic member close to the resonant ring, and the second elastic member and the third elastic member are both fixed to the anchor structure.

2. The MEMS gyroscope according to claim 1, wherein: The MEMS gyroscope operates in a full-angle mode or a force balance mode.

3. The MEMS gyroscope according to claim 1, wherein: The mass blocks include four first mass blocks located at azimuth angles of (i-1)*45°, i=1, 3, 5, 7, respectively, and four second mass blocks located at azimuth angles of (i-1)*45°, i=2, 4, 6, 8, respectively.

4. The MEMS gyroscope according to claim 3, wherein: The mass block further includes eight third mass blocks located at azimuth angles of 22.5°+(i-1)*45°, i=1, 2, ..., 8, respectively.

5. The MEMS gyroscope according to claim 1, wherein: The anchor point structure is a ring structure with a cavity inside.

6. The MEMS gyroscope according to claim 5, wherein: The shape of a side of the anchor structure close to the mass block is rotationally symmetric about the center.

7. The MEMS gyroscope according to claim 6, wherein: The shape of the anchor structure on the side close to the mass block is circular, and the mass block is fan-shaped.

8. The MEMS gyroscope according to claim 1, wherein: The number of the second elastic members is two, and the two second elastic members are respectively located on both sides of one end of the mass block close to the anchor structure; the number of the third elastic members is two, and the two third elastic members are respectively located on both sides of one end of the mass block close to the resonant ring.

9. The MEMS gyroscope according to claim 1, wherein: The second elastic member and the third elastic member are both first comb-shaped springs extending along the radial direction.

10. The MEMS gyroscope according to claim 9, wherein: The first elastic member is a second comb-shaped spring extending along the circumferential direction.

11. The MEMS gyroscope according to claim 1, wherein: The transducer includes one or more of a first electrode assembly arranged on a side of the resonant ring away from the mass block, a second electrode assembly arranged on the resonant ring, a third electrode assembly arranged on the mass block, a fourth electrode assembly arranged between adjacent mass blocks, and a fifth electrode assembly arranged between the mass block and the resonant ring.

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