A three-axis MEMS gyroscope

Abstract

The present invention provides a three-axis MEMS gyroscope, comprising a substrate, a sensing unit elastically connected to the substrate, and a driving unit coupled to the sensing unit and driving the sensing unit to move, wherein the substrate comprises four anchor structures respectively located at the four corners of a rectangle and four coupling structures respectively elastically connected to the anchor structures; the driving unit comprises four driving members respectively located at the inner positions of the four corners of the rectangle and one end of which is elastically connected to the adjacent coupling structures; the sensing unit comprises four X / Y mass blocks respectively arranged in each of the clearance intervals and elastically connected to the adjacent coupling structures to form a rectangular frame, and four Z mass blocks respectively elastically connected to the driving members and located on the side of the driving members away from the anchor structures. The gyroscope of the present invention is differentially driven, can realize differential detection, and reduce orthogonal error.

Description

[Technical field]

[0001] The present invention relates to the field of MEMS sensors, and more specifically, to a three-axis MEMS gyroscope. [Background technology]

[0002] MEMS (Micro Electro Mechanical systems) gyroscopes are silicon micro-electromechanical gyroscopes, which are typical angular velocity micro-sensors. They are widely used in the consumer electronics market due to their 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] The MEMS out-of-plane swing gyroscope is a typical representative of MEMS out-of-plane detection gyroscopes. The driving mode of the MEMS swing gyroscope swings around the axis of the vertical mass block. When the angular velocity Ω is applied, due to the Coriolis effect, the gyroscope transfers energy to the sensitive mode, causing the vibration plate to swing out-of-plane under relative drive. The size of Ω can be obtained by detecting the displacement of the out-of-plane swing.

[0004] 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.

[0005] Therefore, it is necessary to improve the relevant technology and provide a three-axis MEMS gyroscope. [Summary of the invention]

[0006] The purpose of the present invention is to provide a three-axis MEMS gyroscope to solve the problem of error superposition caused by detection mode coupling of the three-axis detection MEMS gyroscope in the related art.

[0007] The technical solution of the present invention is as follows:

[0008] A three-axis MEMS gyroscope comprises a substrate, a sensor unit elastically connected to the substrate, and a driving unit coupled to the sensor unit and driving the sensor unit to move, wherein:

[0009] The base includes four anchor structures respectively located at four corners of a rectangle and four coupling structures respectively elastically connected to the anchor structures, and a gap is formed between adjacent coupling structures;

[0010] The driving unit comprises four driving members respectively located at the inner positions of the four corners of the rectangle and elastically connected to the adjacent coupling structures at one end, the four driving members are all frame-shaped, and the four driving members are surrounded by a ring and are symmetrically arranged;

[0011] The sensing unit includes four X / Y mass blocks, which are respectively arranged in each of the yielding intervals and elastically connected to the adjacent coupling structures to form a rectangular frame, and four Z mass blocks, which are respectively elastically connected to the driving member and located on the side of the driving member away from the anchor point structure, and the adjacent Z mass blocks are elastically connected.

[0012] Preferably, the anchor point structure includes a plurality of sub-anchor points of the same shape and arranged at intervals, and the coupling structure includes a coupling ring mounted outside the anchor point structure, the inner side of the coupling ring extends into the intervals between the sub-anchor points to form a coupling beam connected to the sub-anchor points, and the coupling beam has a bending portion extending into the intervals between the sub-anchor points.

[0013] Preferably, a T-shaped slot is extended inwardly at the end of the X / Y mass block near the coupling ring, and a T-shaped flexible beam is extended outwardly at the outer wall of the coupling ring. The T-shaped flexible beam is accommodated in the T-shaped slot and connected to the X / Y mass block, so that the four X / Y mass blocks and the coupling structure are elastically connected to form a rectangular frame through the T-shaped flexible beam and the T-shaped flexible slot.

[0014] Preferably, a long groove extending along the width direction of the X / Y mass block is opened in the middle part, and the base also includes a mass block anchor point accommodated in the long groove, and a flexible beam with a bending portion extending from the inner wall of the long groove toward the mass block anchor point, the flexible beam is connected to the mass block anchor point, and the bending portion bends from the middle part of the long groove toward both ends.

[0015] Preferably, the driving member includes two extension portions extending in a direction perpendicular to the diagonal line corresponding to the rectangle and an outer protrusion connected between the two extension portions and protruding toward the corresponding rectangular corner. The two ends of the outer protrusion close to the rectangular corner side extend outward to form a T-shaped connecting beam with a bending portion, and the tail of the T-shaped connecting beam is connected to the outer wall of the corresponding coupling ring.

[0016] Preferably, the base also includes a first driving member anchor point spaced apart at one side of the outer protrusion, a first guide beam is connected between the first driving member anchor point and the outer protrusion, and a middle portion of the first guide beam is bent along the outer protrusion; the base also includes a second driving member anchor point spaced apart at one side of the extension portion, a second guide beam is connected between the second driving member anchor point and the extension portion, and a middle portion of the second guide beam is bent along the extension portion.

[0017] Preferably, a Z mass block is arranged between the two extension parts of the same driving member, and one side of the Z mass block close to the corresponding driving member extends to form a first flexible beam connected to the inner side of the extension part, and the middle part of the first flexible beam bends and extends toward the middle part of the notch.

[0018] Preferably, four Z mass blocks are arranged in a ring on the diagonal line of the rectangle, adjacent Z mass blocks are separated to form gaps, and second flexible beams are connected between adjacent Z mass blocks, and the middle part of the second flexible beam is bent along the length direction of the gap.

[0019] Preferably, the three-axis MEMS gyroscope further includes a driving transducer arranged corresponding to the driving member, a first detection transducer arranged corresponding to the X / Y mass block, and a second detection transducer arranged corresponding to the Z mass block.

[0020] The beneficial effects of the present invention are:

[0021] 1. In the present invention, the gyro sensitive mass block and the detection electrode are both symmetrically arranged to facilitate differential detection;

[0022] 2. The gyro drive mode is differential drive, which can effectively improve the stability of gyro drive;

[0023] 3. The three-axis detection modes of the gyroscope XYZ can all achieve anti-phase vibration, effectively immune to the influence of acceleration shock and orthogonal error;

[0024] 4. The gyro 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 between different modal motions, reduces the displacement of the non-moving mass block, reduces the orthogonal error, and is beneficial to the bias stability of the sensor;

[0025] 5. The gyro mass block is elastically connected to the mass through a decoupling structure to achieve anti-phase motion between different mass blocks and effectively form differential detection;

[0026] 6. The angular velocity of the three axes of the gyroscope is detected independently, which effectively avoids the coupling of detection errors of different axes and improves the detection accuracy of the gyroscope.

Brief Description of the Drawings

[0027] Figure 1 It is a schematic diagram of the planar structure of the three-axis MEMS gyroscope of the present invention;

[0028] Figure 2 A top view of the arrangement positions of the detection ring energy device (also called the detection electrode) and the in-plane driving transducer (also called the in-plane driving electrode) in the MEMS gyroscope of the present invention;

[0029] Figure 3 yes Figure 2 Side view of

[0030] Figure 4 It is a schematic diagram of the driving mode of the Z-axis angle detection principle of the three-axis MEMS gyroscope of the present invention;

[0031] Figure 5 It is a detection mode schematic diagram of the Z-axis angle detection principle of the three-axis MEMS gyroscope of the present invention;

[0032] Figure 6 It is a schematic diagram of the driving mode of the X-axis angle detection principle of the three-axis MEMS gyroscope of the present invention;

[0033] Figure 7 It is a detection mode schematic diagram of the X-axis angle detection principle of the three-axis MEMS gyroscope of the present invention;

[0034] Figure 8 It is a schematic diagram of the driving mode of the Y-axis angle detection principle of the three-axis MEMS gyroscope of the present invention;

[0035] Fig. 9 It is a detection mode schematic diagram of the Y-axis angle detection principle of the three-axis MEMS gyroscope of the present invention. [Specific implementation method]

[0036] The present invention will be further described below in conjunction with the accompanying drawings and implementation modes.

[0037] like Figure 1 As shown in FIG. , the three-axis MEMS gyroscope of the embodiment of the present invention includes a substrate 1 ( Figure 1 The middle substrate 1 is plate-shaped, and below each component, there is a blank space in the figure), a sensing unit 2 elastically connected to the substrate 1, and a driving unit 3 coupled to the sensing unit 2 and driving the sensing unit 2 to move, wherein the substrate 1 includes four anchor structures 4 respectively located at the four corners of a rectangle and four coupling structures 5 respectively elastically connected to the anchor structures 4, and a gap is formed between adjacent coupling structures 5.

[0038] The driving unit 3 includes four driving members 31, each of which is located at the four corners of the rectangle and elastically connected to the adjacent coupling structure 5 at one end. The four driving members 31 are all frame-shaped, and the four driving members 31 are surrounded by a ring and are symmetrically arranged.

[0039] The sensing unit 2 includes four X / Y mass blocks 21, which are respectively arranged in each clearance interval and elastically connected to the adjacent coupling structure 5 to form a rectangular frame, and four Z mass blocks 22, which are respectively elastically connected to the driving member 31 and located on the side of the driving member 31 away from the anchor structure 4, and adjacent Z mass blocks 22 are elastically connected.

[0040] Among them, the anchor point structure 4 includes two sub-anchor points 41 of the same shape and arranged at an interval, and the coupling structure 5 includes a coupling ring 51 arranged outside the two sub-anchor points 41, and the inner side of the coupling ring 51 extends toward the interval between the two sub-anchor points 41 to form a coupling beam 52 connected to the sub-anchor points, and the coupling beam 52 has a bending portion extending into the interval between the two sub-anchor points 41.

[0041] Among them, the inner shape of the X / Y mass block 21 matches the outer wall shape of the driving member 31 and is symmetrical about the corresponding side of the rectangle. The end of the X / Y mass block 21 close to the coupling ring 51 extends inward to form a T-shaped groove, and the outer wall of the coupling ring 51 extends outward to form a T-shaped flexible beam 16. The T-shaped flexible beam 16 is accommodated in the T-shaped groove and connected to the X / Y mass block 21, so that the four X / Y mass blocks 21 and the coupling structure 5 are elastically connected through the T-shaped flexible beam 16 and the T-shaped flexible groove to form a rectangular frame.

[0042] Among them, a long groove extending along the width direction is opened in the middle of the X / Y mass block 21, and the base 1 also includes a mass block anchor point 42 accommodated in the long groove. The inner wall of the long groove extends toward the mass block anchor point 42 and has a flexible beam 17 with a bending portion. The flexible beam 17 is connected to the mass block anchor point 42, and the bending portion bends from the middle of the long groove to both ends.

[0043] Among them, the driving member 31 includes two extension parts extending in a direction perpendicular to the diagonal line corresponding to the rectangle and an outer protrusion connected between the two extension parts and protruding toward the corresponding anchor structure 4, and the two ends of the outer protrusion close to the anchor structure 4 extend outward to form a T-shaped connecting beam 11 with a bending portion, and the tail of the T-shaped connecting beam 11 is connected to the outer wall of the corresponding coupling ring 51.

[0044] The base 1 further includes a first driving member anchor point 43 spaced apart on one side of the outer protrusion, a first guide beam 12 is connected between the first driving member anchor point 43 and the outer protrusion, and a middle portion of the first guide beam 12 is bent along a gap between the outer protrusion and the X / Y mass block 21 .

[0045] Preferably, the base 1 further comprises a second driving member anchor point 44 spaced apart on one side of the extension portion, a second guide beam 13 is connected between the second driving member anchor point 44 and the extension portion, and a middle portion of the second guide beam 13 is bent along a gap between the extension portion and the X / Y mass block 21 .

[0046] A notch is formed between the two extension parts of the same driving member 31, and a Z mass block 22 is arranged in the notch of each driving member 31. One side of the Z mass block 22 close to the corresponding driving member 31 extends to form a first flexible beam 14 connected to the inner side of the extension part, and the middle part of the first flexible beam 14 bends and extends toward the middle part of the notch.

[0047] Among them, four Z mass blocks 22 are arranged in a ring on the diagonal line of the rectangle, the width of the end of the Z mass block 22 away from the driving member 31 is smaller than the width of the end of the Z mass block 22 close to the driving member 31, adjacent Z mass blocks 22 are separated to form a gap, and the second flexible beam 15 is connected between adjacent Z mass blocks 22, and the middle part of the second flexible beam 15 is bent along the length direction of the gap.

[0048] The three-axis MEMS gyroscope further includes a driving transducer arranged corresponding to the driving member 31 , a first detection transducer arranged corresponding to the X / Y mass block 21 , and a second detection transducer arranged corresponding to the Z mass block 22 .

[0049] Figure 2 A top view of the arrangement positions of the detection ring energy device (also called detection electrode) and the in-plane driving transducer (also called in-plane driving electrode) in the three-axis detection MEMS gyroscope of the present invention, Figure 3 yes Figure 2 The side view of the two figures shows that the short side of the Z mass block and the short side of the driver are separated to form a rectangular clearance space. When working, an in-plane driving transducer is set in the clearance space to drive the driver to vibrate. The X detection surface transducer and the Y detection surface transducer are symmetrically set on the X / Y mass block. The Z detection surface transducer is embedded in the rectangular frame of the decoupling mass block.

[0050] In the present invention, the driving member is connected to the anchor area through a flexible guide beam, and the flexible guide beam can provide a single degree of freedom in a plane. The X / Y mass block is connected to the coupling ring through a first flexible beam, and the first flexible beam can provide the freedom of rotation in the plane and flipping out of the plane. The Z mass block and the driving member are connected through a second flexible beam, and the second flexible beam provides the Z mass block with a single degree of freedom in the direction of movement of the driving member perpendicular to the driving member. The decoupling structure is connected to the Z mass block through a third flexible beam, and the third flexible beam provides the decoupling structure with a single degree of freedom in the direction of movement of the driving member parallel to the driving member.

[0051] The gyroscope of the present invention has four modes when working, one is the drive mode; the other three modes are the X-axis, Y-axis, and Z-axis detection modes. The angular velocity sensitivity principle of the gyroscope of the present invention is explained below in combination with the working modes.

[0052] Specifically, Figure 4 It is a schematic diagram of the driving mode of the Z-axis angle detection principle of the three-axis detection MEMS gyroscope of the present invention. Figure 5It is a detection mode schematic diagram of the Z-axis angle detection principle of the three-axis detection MEMS gyroscope of the present invention. Combining the two figures, it can be seen that during the Z-axis angle detection process, the gyroscope has two vibration modes. In the first mode, the Z mass block moves circumferentially within the plane, and in the second mode, the Z mass block moves radially within the plane. Through an external driving force, the new scheme is driven to drive the vibration of the modal vibration type. At this time, when the gyroscope applied by the present invention is subjected to the Z-axis angular velocity ω, according to the Coriolis principle, the angular velocity ω will generate a Coriolis force along the y-axis direction, and the Coriolis force will force the gyroscope applied by the present invention to generate vibration with the Z-axis detection modal vibration type. Finally, by detecting the vibration displacement of the gyroscope applied by the present invention in the radial direction, the size of the angular velocity ω can be obtained.

[0053] Figure 6 It is a schematic diagram of the driving mode of the three-axis detection MEMS gyro X-axis angle detection principle of the present invention, Figure 7 It is a detection mode schematic diagram of the X-axis angle detection principle of the three-axis detection MEMS gyroscope of the present invention. Combining the two figures, it can be seen that the gyroscope of the X-axis angle detection scheme has two vibration modes. The first mode is that the X / Y mass block swings around the center of the mass block in the plane; the second mode is the X / Y mass block swinging mode out of the plane. The gyroscope is driven to vibrate with a driving modal vibration type through an external driving force. At this time, when the gyroscope of the present invention is subjected to an X-axis angular velocity ω, according to the Coriolis principle, the angular velocity ω will generate a Coriolis force along the Z-axis direction, and the Coriolis force will force the gyroscope of the present invention to generate vibration with an X-axis detection modal vibration type. Finally, by detecting the vibration displacement of the gyroscope of the present invention along the Z-axis direction, the size of the angular velocity ω can be obtained.

[0054] Figure 8 It is a schematic diagram of the driving mode of the Y-axis angle detection principle of the three-axis detection MEMS gyroscope of the present invention. Fig. 9 It is a detection mode schematic diagram of the Y-axis angle detection principle of the three-axis detection MEMS gyroscope of the present invention. Combining the two figures, it can be seen that the gyroscope of the Y-axis angle detection scheme has two vibration modes. The first mode is that the X / Y mass block swings around the center of the mass block in the plane, and the second mode is the X / Y mass block swinging mode out of the plane. Through an external driving force, the gyroscope is driven to drive the vibration of the modal vibration type. At this time, when the gyroscope of the present invention is subjected to the Y-axis angular velocity ω, according to the Coriolis principle, the angular velocity ω will generate a resultant Coriolis force along the Z-axis direction, and the resultant Coriolis force will force the gyroscope of the present invention to generate vibration with a Y-axis detection modal vibration type. Finally, by detecting the vibration displacement of the gyroscope of the new scheme along the Z-axis direction, the size of the angular velocity ω can be obtained.

[0055] In actual engineering practice, a gyroscope has a number of capacitors, which have the following functions: a) to generate the external driving force required to force the gyroscope of the present invention to drive the vibration of the modal vibration type; b) to detect the vibration displacement of the gyroscope along the detection modal vibration direction; c) to suppress the orthogonal error of the gyroscope.

[0056] 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 three-axis MEMS gyroscope, comprising a substrate, a sensor unit elastically connected to the substrate, and a driving unit coupled to the sensor unit and driving the sensor unit to move, characterized in that: The three-axis MEMS gyroscope is rectangular; The substrate comprises four anchor structures respectively located at four corners of the three-axis MEMS gyroscope and four coupling structures respectively elastically connected to the anchor structures, and a clearance interval is formed between adjacent coupling structures; The driving unit comprises four driving members respectively located at the inner positions of the four corners of the three-axis MEMS gyroscope and elastically connected to the adjacent coupling structures at one end, the four driving members are all frame-shaped, and the four driving members are surrounded by a ring and symmetrically arranged; The sensing unit includes four X / Y mass blocks, which are respectively arranged in each of the yielding intervals and elastically connected to the adjacent coupling structures to form a rectangular frame, and four Z mass blocks, which are respectively elastically connected to the driving member and located on the side of the driving member away from the anchor point structure, and the adjacent Z mass blocks are elastically connected.

2. The three-axis MEMS gyroscope according to claim 1, characterized in that: The anchor point structure includes a plurality of sub-anchor points of the same shape and arranged at intervals, and the coupling structure includes a coupling ring sleeved outside the anchor point structure, the inner side of the coupling ring extends into the intervals between the sub-anchor points to form a coupling beam connected to the sub-anchor points, and the coupling beam has a bending portion extending into the intervals between the sub-anchor points.

3. The three-axis MEMS gyroscope according to claim 2, characterized in that: The X / Y mass block has a T-shaped groove extending inwardly near the end of the coupling ring, and a T-shaped flexible beam extending outwardly at the outer wall of the coupling ring. The T-shaped flexible beam is accommodated in the T-shaped groove and connected to the X / Y mass block, so that the four X / Y mass blocks and the coupling structure are elastically connected to form a rectangular frame through the T-shaped flexible beam and the T-shaped flexible groove.

4. The three-axis MEMS gyroscope according to claim 3, characterized in that: A long groove extending along the width direction is opened in the middle of the X / Y mass block, and the base also includes a mass block anchor point accommodated in the long groove, and a flexible beam with a bending portion extending from the inner wall of the long groove toward the mass block anchor point, the flexible beam is connected to the mass block anchor point, and the bending portion bends from the middle of the long groove toward both ends.

5. The three-axis MEMS gyroscope according to claim 2, characterized in that: The driving member includes two extension parts extending in a direction perpendicular to the diagonal line corresponding to the rectangle and an outer protrusion connected between the two extension parts and protruding toward the corresponding rectangular corner. The two ends of the outer protrusion close to the rectangular corner side extend outward to form a T-shaped connecting beam with a bending portion, and the tail of the T-shaped connecting beam is connected to the outer wall of the corresponding coupling ring.

6. The three-axis MEMS gyroscope according to claim 5, characterized in that: The base also includes a first driving member anchor point spaced apart at one side of the outer protrusion, a first guide beam is connected between the first driving member anchor point and the outer protrusion, and a middle portion of the first guide beam is bent along the outer protrusion; the base also includes a second driving member anchor point spaced apart at one side of the extension portion, a second guide beam is connected between the second driving member anchor point and the extension portion, and a middle portion of the second guide beam is bent along the extension portion.

7. The three-axis MEMS gyroscope according to claim 5, characterized in that: A gap is formed between the two extension parts of the same driving member, and a Z mass block is arranged in the gap of each driving member. One side of the Z mass block close to the corresponding driving member extends to form a first flexible beam connected to the inner side of the extension part, and the middle part of the first flexible beam bends and extends toward the middle part of the gap.

8. The three-axis MEMS gyroscope according to claim 7, characterized in that: The four Z mass blocks are arranged in a ring on the diagonal line of the rectangle, adjacent Z mass blocks are separated to form gaps, and second flexible beams are connected between adjacent Z mass blocks, and the middle part of the second flexible beam is bent along the length direction of the gap.

9. The three-axis MEMS gyroscope according to claim 1, characterized in that: The three-axis MEMS gyroscope further includes a driving transducer arranged corresponding to the driving member, a first detection transducer arranged corresponding to the X / Y mass block, and a second detection transducer arranged corresponding to the Z mass block.

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