A MEMS gyroscope

Abstract

The present invention provides a MEMS gyroscope, comprising an anchor unit, a sensing unit elastically connected to the anchor unit, and a driving unit elastically connected to the anchor unit and the sensing unit; the anchor unit comprises four corner anchor structures and four center anchors respectively located at four corners of a rectangle; the sensing unit comprises four first mass blocks elastically connected between each corner anchor structure and the corresponding center anchor and mutually forming a clearance space, and four second mass blocks and four decoupling mass blocks respectively located in each clearance space; the first mass block, the second mass block and the decoupling mass block are all within the rectangle; the driving unit comprises four driving members respectively connected to the outside of the second mass block. The gyroscope of the present invention can realize independent detection of three-axis angular velocity, differential detection, and vibration torque balance, effectively immune to the influence of acceleration shock and orthogonal error, and improve detection accuracy.

Description

[Technical field]

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

[0002] Micromechanical gyroscopes, or MEMS (Micro Electro Mechanical systems) gyroscopes, are a typical angular velocity micro sensor, which is widely used in the consumer electronics market due to its small size, low power consumption, and easy processing. In recent years, with the gradual improvement of the performance of MEMS gyroscopes, MEMS gyroscopes have been widely used in the fields of automobiles, industry, virtual reality, etc.

[0003] US Patent US8459110B2 (Chinese equivalent CN102183246B) discloses an integrated MEMS gyroscope, including a first driving mass block and a second driving mass block, which respond to the angular velocity sensed by the gyroscope to generate a sensing motion, and then detect the sensing motion to achieve the measurement of the angular velocity. This kind of MEMS gyroscope can achieve three-axis detection, however, the detection modes of this kind of gyroscope are mutually coupled, resulting in error superposition.

[0004] Therefore, it is necessary to improve the existing technology and provide a MEMS gyroscope. [Summary of the invention]

[0005] The purpose of the present invention is to provide a MEMS gyroscope to solve the problem of error superposition caused by detection mode coupling of a three-axis detection MEMS gyroscope in the prior art.

[0006] The technical solution of the present invention is as follows:

[0007] A MEMS gyroscope comprises an anchor unit, a sensing unit elastically connected to the anchor unit, and a driving unit elastically connected to the anchor unit and the sensing unit;

[0008] The anchor point unit includes four corner anchor point structures respectively located at four corners of a rectangle and four center anchor points located in the rectangle and spaced apart from the four corner anchor point structures respectively;

[0009] The sensing unit comprises four first mass blocks which are elastically connected between each of the corner anchor point structures and the corresponding central anchor point and mutually form a clearance space, four second mass blocks which are respectively located in each of the clearance spaces, and four decoupling mass blocks which are respectively located in each of the clearance spaces and elastically connected to the second mass blocks; the first mass block, the second mass block and the decoupling mass block are all within the rectangle, and the decoupling mass block is located on the inner side of the second mass block, and adjacent decoupling mass blocks are elastically connected;

[0010] The driving unit includes four driving members respectively connected to the outer sides of the second mass block, and two ends of the driving members are elastically connected to the adjacent corner anchor point structures.

[0011] Further, the corner anchor structure includes a corner anchor located at the corner position of the rectangle, a coupling ring elastically connected to the corner anchor, and a driving anchor spaced apart from the corner anchor and close to the corresponding driving member, the outer side of the coupling ring extends to form a first flexible beam connected to the corresponding first mass block and a first connecting beam connected to the corresponding driving member, and the driving member extends to form a first guide beam connected to the driving anchor.

[0012] Furthermore, the corner anchor point includes a plurality of sub-anchor points arranged at intervals, the coupling ring is sleeved outside all the sub-anchor points, and the inner side of the coupling ring extends toward the sub-anchor point to form a first coupling beam connected to the sub-anchor point.

[0013] Further, the first flexible beam includes a first main body extending from the coupling ring toward the first mass block and a first elastic beam connecting the first main body and the first mass block.

[0014] Further, the first connecting beam includes a first connecting body extending from the coupling ring toward the driving member and a first elastic connecting beam connecting the first connecting body and the driving member.

[0015] Furthermore, a side of the first mass block close to the corresponding central anchor point extends to form a second flexible beam connected to the central anchor point.

[0016] Furthermore, the second mass block extends to form a second guide beam connected to the corresponding driving member.

[0017] Furthermore, a second elastic beam connected to a corresponding side of the second mass block is provided on one side of the decoupling mass block close to the second mass block, and a middle portion of the second elastic beam is bent along a gap between the decoupling mass block and the second mass block.

[0018] Furthermore, the anchor point unit further comprises a third guide beam anchor point close to the decoupling mass block, and the decoupling mass block extends to form a third guide beam connected to the third guide beam anchor point.

[0019] Further, one end of the decoupling mass away from the second mass extends to form a second coupling beam connected to an adjacent decoupling mass.

[0020] Furthermore, the MEMS gyroscope also includes a first transducer coupled to the driving unit and a second transducer coupled to the sensing unit, the first transducer is arranged in a one-to-one correspondence with the driving element, and the second transducer is arranged in a one-to-one correspondence with the first mass block and the decoupling mass block.

[0021] Furthermore, the first transducer includes any one of a capacitive transducer, an inductive transducer, a thermoelectric transducer, and a piezoelectric transducer, or any combination thereof, and the second transducer includes any one of a capacitive transducer, an inductive transducer, a thermoelectric transducer, and a piezoelectric transducer, or any combination thereof.

[0022] The principle of the present invention is:

[0023] In drive mode:

[0024] The driving unit is associated with the first mass block through a corner anchor structure. The driving unit drives the first mass block to move in a 0° / 90° direction within a plane. At the same time, the driving unit drives the second mass block to move in a 45° / 135° direction within a plane. The movement directions of the four first mass blocks and the four second mass blocks form differential modes respectively.

[0025] In detection mode:

[0026] The first mass blocks respond to angular velocities in two directions in the surface in pairs; when the external angular velocity ω applied to the MEMS gyroscope is located in the surface and perpendicular to the movement direction of the first mass block, according to the Coriolis principle, the angular velocity ω will generate a Coriolis force in an orthogonal direction outside the surface, and the Coriolis force will force the first mass block to flip out of the surface; for the first mass block: the two first mass blocks located at 0° respond to the angular velocity ω along 90° in the surface, and because the two first mass blocks located at 0° move in opposite directions in the driving mode, the flipping directions of the two in the detection mode are also opposite, forming differential detection; similarly, the two first mass blocks located at 90° respond to the angular velocity ω along 0° in the surface, and the two form differential detection in the detection mode;

[0027] The second mass block responds to the angular velocity orthogonal to the in-plane direction; when the MEMS gyroscope is subjected to an external angular velocity ω in a direction orthogonal to the in-plane, according to the Coriolis principle, the angular velocity ω will generate an in-plane Coriolis force perpendicular to the movement direction of the second mass block, and the Coriolis force will force the second mass block to move in a direction perpendicular to the driving mode; for the second mass block, the two second mass blocks located at 45° move in opposite directions in the detection mode, and the two second mass blocks located at 135° move in opposite directions in the detection mode, and the four second mass blocks form differential detection in the detection mode.

[0028] The beneficial effects of the present invention are:

[0029] The gyro's sensitive mass blocks are symmetrically arranged to facilitate differential detection. The gyro's drive mode is differential drive, which can effectively improve the stability of the gyro's drive. The gyro's three-axis detection modes can all achieve anti-phase vibration, so the gyro's differential detection can be achieved, and the vibration torque is balanced, effectively immune to the influence of acceleration shock and orthogonal error. The gyro's mass block is elastically connected to the anchor point through a decoupling structure, which effectively reduces the coupling between different modal motions of the mass block, avoids interference from different modal motions, reduces the displacement of non-moving mass blocks, reduces orthogonal errors, and is beneficial to the bias stability of the sensor. The gyro's mass block is elastically connected to the mass through a decoupling structure to achieve anti-phase motion between different mass blocks, effectively forming differential detection. The gyro's three-axis angular velocity is independently detected, which effectively avoids the coupling of detection errors of different axes and improves the gyro's detection accuracy.

Brief Description of the Drawings

[0030] Figure 1 Schematic diagram of the top view of the MEMS gyroscope in an embodiment of the present invention;

[0031] Figure 2 It is a schematic diagram of the state of the MEMS gyroscope in the driving mode according to an embodiment of the present invention;

[0032] Figure 3 It is a schematic diagram of the state of the MEMS gyroscope in the x-axis detection mode according to an embodiment of the present invention;

[0033] Figure 4 It is a schematic diagram of the state of the MEMS gyroscope in the y-axis detection mode according to an embodiment of the present invention;

[0034] Figure 5 It is a schematic diagram of the state of the MEMS gyroscope in the z-axis detection mode according to an embodiment of the present invention;

[0035] Figure 6 for Figure 1 Enlarged view of part a;

[0036] Figure 7FIG. 4 is a layout diagram of a first transducer and a second transducer of a MEMS gyroscope in an embodiment of the present invention. [Specific implementation method]

[0037] The present invention will be further described below in conjunction with the accompanying drawings and implementation modes.

[0038] like Figure 1 As shown in , a MEMS gyroscope provided in an embodiment of the present invention includes an anchor unit 1, a sensor unit 2 elastically connected to the anchor unit 1, and a driving unit 3 elastically connected to the anchor unit 1 and the sensor unit 2;

[0039] The anchor point unit 1 comprises four corner anchor point structures 11 respectively located at four corners of a rectangle and four center anchor points 12 located in the rectangle and spaced apart from the four corner anchor point structures 11 respectively;

[0040] The sensing unit 2 includes four first mass blocks 21 elastically connected between each corner anchor point structure 11 and the corresponding central anchor point 12 and mutually forming a clearance space, four second mass blocks 22 respectively located in each clearance space, and four decoupling mass blocks 23 respectively located in each clearance space and elastically connected to the second mass blocks 22. The first mass block 21, the second mass block 22 and the decoupling mass block 23 are all within a rectangle, and the decoupling mass block 23 is located on the inner side of the second mass block 22, and adjacent decoupling mass blocks 23 are elastically connected;

[0041] The driving unit 3 includes four driving members 31 respectively connected to the outer sides of the second mass block 22 , and two ends of the driving members 31 are elastically connected to adjacent corner anchor structures 11 .

[0042] The gyroscope of the embodiment of the present invention is in the driving mode, such as Figure 2 As shown in the figure, the driving member 31 is associated with the first mass block through the corner anchor structure 11, and the driving member 31 drives the first mass block 21 to move in the 0° / 90° direction within the plane. At the same time, the driving member 31 drives the second mass block 22 to move in the 45° / 135° direction within the plane, and the movement directions of the four first mass blocks 21 and the four second mass blocks 22 respectively form differential modes.

[0043] In the detection mode, the first mass blocks 21 respond to the angular velocities in two directions in the surface in pairs; Figure 3 and Figure 4As shown in , when the external angular velocity ω of the gyroscope is located in the plane and perpendicular to the movement direction of the first mass block 21, according to the Coriolis principle, the angular velocity ω will generate a Coriolis force in an orthogonal direction outside the plane, and the Coriolis force will force the first mass block 21 to flip out of the plane; for the first mass block 21: the two first mass blocks 21 located at 0° respond to the angular velocity ω of 90° along the surface, and because the two first mass blocks 21 located at 0° move in opposite directions in the driving mode, the flipping directions of the two in the detection mode are also opposite, forming differential detection; similarly, the two first mass blocks 21 located at 90° respond to the angular velocity ω of 0° along the surface, and the two form differential detection in the detection mode;

[0044] The second mass responds to the angular velocity orthogonal to the in-plane direction; Figure 5 As shown in , when the direction of the external angular velocity ω applied to the gyroscope is orthogonal to the plane, according to the Coriolis principle, the angular velocity ω will generate a Coriolis force in the plane perpendicular to the movement direction of the second mass block 22, and the Coriolis force will force the second mass block 22 to move in a movement direction perpendicular to the driving mode; for the second mass block 22, the two second mass blocks 22 located at 45° move in opposite directions in the detection mode, and the two second mass blocks 22 located at 135° move in opposite directions in the detection mode, and the four second mass blocks form differential detection in the detection mode.

[0045] like Figure 6 As shown in , the corner anchor structure 11 includes a corner anchor 111 located at the corner position of a rectangle, a coupling ring 112 elastically connected to the corner anchor 111, and a driving anchor 113 spaced apart from the corner anchor 111 and close to the corresponding driving member 31. The outer side of the coupling ring 112 extends to form a first flexible beam 114 connected to the corresponding first mass block 21 and a first connecting beam 115 connected to the corresponding driving member 31. The driving member 31 extends to form a first guide beam 32 connected to the driving anchor 113; specifically, the first guide beam 32 is formed by the two ends of the driving member 31 extending outward respectively, and the middle part of the first guide beam 32 is bent and extended in a direction away from the corresponding driving member 31; in this embodiment, the movement direction of the driving member 31 is guided by the first guide beam 32, so that the driving member 31 moves in the direction of 45° / 135° in the plane; through the corner anchor structure 11, the driving member 31 is associated with the first mass block 21 to drive the first mass block to move in the plane.

[0046] The corner anchor point 111 includes a plurality of sub-anchor points 1111, and the coupling ring 112 is sleeved outside all the sub-anchor points 1111. The inner side of the coupling ring 112 extends toward the sub-anchor point 1111 to form a first coupling beam 116 connected to the sub-anchor point 1111. Specifically, as Figure 6As shown in the figure, the corner anchor point 111 includes two sub-anchor points 1111 arranged at an interval, and the coupling ring 112 is sleeved outside the two sub-anchor points 1111. The inner side of the coupling ring 112 extends into the interval between the two sub-anchor points 1111 to form a first coupling beam 116 connected to the sub-anchor points 1111; through the first coupling beam 116, the coupling ring 112 has the freedom of in-plane rotation and out-of-plane flipping.

[0047] like Figure 6 As shown in , the first flexible beam 114 includes a first main body 1141 extending from the coupling ring 112 toward the first mass block 21 and a first elastic beam 1142 connecting the first main body 1141 and the first mass block 21; specifically, a first connection gap 211 is provided on a side of the first mass block 21 close to the corresponding coupling ring 112, and the first elastic beam 1142 extends from an end of the first main body 1141 away from the coupling ring 112 to the first connection gap 211 and is connected to the first mass block 21. The first connection beam 115 includes a first connection main body 1151 extending from the coupling ring 112 toward the driving member 31 and a first elastic connection beam 1152 connecting the first connection main body 1151 and the driving member 31; specifically, the first elastic connection beam 1152 extends from an end of the first connection main body 1151 away from the coupling ring 112 and is connected to the corresponding driving member 31. Through the above structure, in the driving mode, the first mass block 21 is coupled to the driving member 31, and since the first elastic beam 1142 has a large stiffness along the 0° / 90° direction, in the driving mode, the first mass block 21 moves in the 0° / 90° direction within the plane, and the first elastic beam 1142 and the first coupling beam 116 have a small stiffness along the out-of-plane direction, so the first mass block 21 has the freedom to flip out-of-plane.

[0048] like Figure 6 As shown in the figure, the first mass block 21 extends on one side close to the corresponding center anchor point 12 to form a second flexible beam 24 connected to the center anchor point 12; specifically, a second connecting gap 212 is opened on one side of the first mass block 21 close to the corresponding center anchor point 12, and the first mass block 21 extends in the second connecting gap 212 to form a second flexible beam 24 connected to the center anchor point 12, and the second flexible beam 24 is bent in the length direction of the second connecting gap 212 to form a flexible structure.

[0049] The second mass block 22 extends to form a second guide beam 25 connected to the corresponding driving member 31; specifically, Figure 6As shown in the figure, both sides of the part of the first mass block 21 close to the corresponding corner anchor structure 11 extend toward the corresponding driving member 31 to form a first extension portion 213, the second mass block 22 is located between adjacent first extension portions 213, the second guide beam 25 is formed by extending from both ends of the second mass block 22, and the middle part of the second guide beam 25 is bent in the direction away from the driving member 31; the second guide beam 25 has a large stiffness along the 45° / 135° direction, so in the driving mode, the second mass block 22 is coupled with the driving member 31, and the driving member 31 drives the second mass block 22 to move along the 45° / 135° direction, and at the same time, the second guide beam 25 has a small stiffness along the direction perpendicular to 45° / 135°, so the second mass block 22 has a degree of freedom along the direction perpendicular to 45° / 135°.

[0050] like Figure 6 As shown in , the two sides of the portion of the first mass block 21 close to the corresponding central anchor point 12 extend outward to form a second extension portion 214, and the decoupling mass block 23 is located between the adjacent second extension portions 214; the side of the decoupling mass block 23 close to the second mass block 22 is provided with a second elastic beam 26 connected to the corresponding side of the second mass block 22; specifically, the middle part of the second elastic beam 26 is bent along the gap between the decoupling mass block 23 and the second mass block 22. The anchor point unit 1 also includes a third guide beam anchor point 13 close to the decoupling mass block 23, and the decoupling mass block 23 extends to form a third guide beam 27 connected to the third guide beam anchor point 13; specifically, as shown in Figure 6 As shown in , the third guide beam anchor point 13 is arranged between the decoupling mass block 23 and the corresponding second extension portion 214, the third guide beam 27 is formed by extending from one side of the decoupling mass block 23 close to the second extension portion 214, and the middle part of the third guide beam 27 is bent along the gap between the second extension portion 214 and the decoupling mass block 23. The second elastic beam 26 has a small stiffness along the 45° / 135° direction and a large stiffness in the direction perpendicular to the 45° / 135° direction, and the third guide beam 27 has a large stiffness along the 45° / 135° direction and a small stiffness in the direction perpendicular to the 45° / 135° direction. Therefore, in the driving mode, the decoupling mass block 23 is decoupled from the motion of the second mass block 22, and in the detection mode, the decoupling mass block 23 is coupled with the second mass block 22.

[0051] like Figure 6As shown in , in this embodiment, both sides of the middle part of the first mass block 21 extend toward the corresponding decoupling mass block 23 to form a third extension portion 215; the anchor unit 1 also includes a fourth guide beam anchor point 14 arranged between the third extension portion 215 and the decoupling mass block 23, and a fourth guide beam 28 connected to the fourth guide beam anchor point 14 is arranged on one side of the decoupling mass block 23 close to the third extension portion 215, and the middle part of the fourth guide beam 28 is bent along the gap between the third extension portion 215 and the decoupling mass block 23; the fourth guide beam 28 has a large stiffness along the 45° / 135° direction and a small stiffness in the direction perpendicular to the 45° / 135° direction. The fourth guide beam 28 can achieve the same function as the third guide beam 27. Therefore, in some embodiments, the fourth guide beam 28 may not be provided.

[0052] like Figure 6 As shown in FIG. 1 , one end of the decoupling mass 23 away from the second mass 22 extends to form a second coupling beam 29 connected to the adjacent decoupling mass 23 , so that the decoupling mass 23 are coupled to each other.

[0053] like Figure 7 As shown in , the MEMS gyroscope of this embodiment also includes a first transducer 4 coupled to the driving unit and a second transducer 5 coupled to the sensing unit; the first transducer 4 includes any one or any combination of a capacitive transducer, an inductive transducer, a thermoelectric transducer, and a piezoelectric transducer, and the second transducer 5 includes any one or any combination of a capacitive transducer, an inductive transducer, a thermoelectric transducer, and a piezoelectric transducer. In this embodiment, a first cavity 311 is provided inside the driving member 31, and the first transducer 4 includes four in-plane driving electrodes 41 respectively arranged in the first cavities 311 of the four driving members 31; in this embodiment, a second cavity 231 is provided inside the decoupling mass block 23, and the second transducer 5 includes four in-plane detection electrodes 51 respectively arranged in the second cavities 231 of the four decoupling mass blocks 23, and four out-of-plane detection electrodes 52 arranged outside the plane and respectively located above or below the first mass block 21.

[0054] The above description is only an implementation mode of the present invention. It should be pointed out that, for ordinary technicians in this field, improvements can be made without departing from the creative concept of the present invention, but these all belong to the protection scope of the present invention.

Claims

1. A MEMS gyroscope, comprising an anchor unit, a sensing unit elastically connected to the anchor unit, and a driving unit elastically connected to the anchor unit and the sensing unit, characterized in that: The MEMS gyroscope is rectangular; The anchor point unit includes four corner anchor point structures respectively located at four corner positions of the MEMS gyroscope and four center anchor points located in the MEMS gyroscope and spaced apart from the four corner anchor point structures respectively; The sensing unit comprises four first mass blocks which are elastically connected between each of the corner anchor point structures and the corresponding central anchor point and mutually form a clearance space, four second mass blocks which are respectively located in each of the clearance spaces, and four decoupling mass blocks which are respectively located in each of the clearance spaces and elastically connected to the second mass blocks; the first mass block, the second mass block and the decoupling mass block are all within the rectangle, and the decoupling mass block is located on the inner side of the second mass block, and adjacent decoupling mass blocks are elastically connected; The driving unit includes four driving members respectively connected to the outer sides of the second mass block, and two ends of the driving members are elastically connected to the adjacent corner anchor point structures.

2. The MEMS gyroscope according to claim 1, characterized in that: The corner anchor structure includes a corner anchor located at the corner of the rectangle, a coupling ring elastically connected to the corner anchor, and a driving anchor spaced apart from the corner anchor and close to the corresponding driving member, the outer side of the coupling ring extends to form a first flexible beam connected to the corresponding first mass block and a first connecting beam connected to the corresponding driving member, and the driving member extends to form a first guide beam connected to the driving anchor.

3. The MEMS gyroscope according to claim 2, characterized in that: The corner anchor point includes a plurality of sub-anchor points, the coupling ring is sleeved outside all the sub-anchor points, and the inner side of the coupling ring extends toward the sub-anchor points to form a first coupling beam connected to the sub-anchor points.

4. The MEMS gyroscope according to claim 2, characterized in that: The first flexible beam includes a first body extending from the coupling ring toward the first mass and a first elastic beam connecting the first body and the first mass.

5. The MEMS gyroscope according to claim 2, characterized in that: The first connecting beam includes a first connecting body extending from the coupling ring toward the driving member and a first elastic connecting beam connecting the first connecting body and the driving member.

6. The MEMS gyroscope according to claim 1, characterized in that: A side of the first mass block close to the corresponding central anchor point extends to form a second flexible beam connected to the central anchor point.

7. The MEMS gyroscope according to claim 1, characterized in that: The second mass block extends to form a second guide beam connected to the corresponding driving member.

8. The MEMS gyroscope according to claim 1, characterized in that: A second elastic beam connected to a corresponding side of the second mass block is provided on one side of the decoupling mass block close to the second mass block.

9. The MEMS gyroscope according to claim 1, characterized in that: The anchor point unit further includes a third guide beam anchor point close to the decoupling mass block, and the decoupling mass block extends to form a third guide beam connected to the third guide beam anchor point.

10. The MEMS gyroscope according to claim 1, characterized in that: One end of the decoupling mass away from the second mass extends to form a second coupling beam connected to an adjacent decoupling mass.

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