A fully decoupled three-axis MEMS gyroscope

Abstract

The present invention provides a fully decoupled 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 a coupling anchor point located at the center of a rectangle and a coupling structure elastically connected to the coupling anchor point; the driving unit comprises four driving members respectively located at the inner positions of the four corners of the rectangle; the sensing unit comprises two X mass blocks symmetrically arranged in two of the make-way intervals, two Y mass blocks symmetrically arranged in the other two of the make-way intervals, four Z mass blocks elastically connected to adjacent driving members and located at the four corners of the rectangle, and four Z detection decoupling members elastically connected to adjacent Z mass blocks and each elastically connected around the rectangle. 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 technical field of MEMS sensors, and more specifically, to a fully decoupled three-axis MEMS gyroscope. [Background technology]

[0002] MEMS (Micro-Electro-Mechanical System) gyroscope, also known as silicon micro-electromechanical gyroscope, is a miniature angular velocity sensor made using micromachining technology and microelectronics technology.

[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] Chinese patent application with publication number CN111578921 discloses a micro-electromechanical multi-axis gyroscope, whose orthogonally arranged four-mass three-axis gyroscope structure design determines that the detection modes of its three axes are coupled with each other, and the errors will be superimposed, resulting in excessive errors.

[0005] In order to overcome the above defects of the prior art, it is necessary to develop a three-axis MEMS gyroscope to achieve differential detection. [Summary of the invention]

[0006] The purpose of the present invention is to provide a fully decoupled three-axis gyroscope to solve the problem of weak coupling between gyroscope mass structures and inability to ensure the displacement ratio of the mass block in the related art.

[0007] The technical solution of the present invention is as follows: A fully decoupled 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, characterized in that:

[0008] The substrate comprises a coupling anchor point located at the center of a rectangle and a coupling structure elastically connected to the coupling anchor point;

[0009] 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 base, the four driving members are all frame-shaped, the four driving members are arranged in a ring around the coupling anchor point and are symmetrically arranged, and a gap is formed between adjacent driving members;

[0010] The sensing unit includes two X mass blocks symmetrically arranged in two opposite making way intervals and elastically connected to the coupling structure and the driving member, two Y mass blocks symmetrically arranged in another two opposite making way intervals and elastically connected to the coupling structure and the driving member, four Z mass blocks elastically connected to adjacent driving members and located at four corners of the rectangle, and four Z detection decoupling members elastically connected to adjacent Z mass blocks and arranged around the rectangle, and adjacent Z detection decoupling members are elastically connected.

[0011] Preferably, the coupling structure includes an inner coupling ring sleeved outside the coupling anchor point, and an outer coupling ring sleeved outside the inner coupling ring, the inner side of the inner coupling ring extends along a center line direction of the rectangle to form two inner coupling beams connected to the coupling anchor point, and the inner side of the outer coupling ring extends along a straight line perpendicular to the two inner coupling beams to form two outer coupling beams connected to the inner coupling ring.

[0012] Preferably, the X mass block and the Y mass block extend toward the outer coupling ring near the corresponding coupling structure to form a first connecting beam with a bending portion, and the end of the first connecting beam away from the driving member is connected to the outer wall of the corresponding outer coupling ring.

[0013] Preferably, the base also includes a connecting beam anchor point, and the outer walls of the two corners of one end of the driving member close to the connecting beam anchor point extend outward to form a second connecting beam, and the end of the second connecting beam away from the driving member is connected to the connecting beam anchor point, and the second connecting beam is located in the distance between the outer wall of the driving member and the connecting beam anchor point.

[0014] Preferably, each of the X mass block and the Y mass block is provided with a groove, and the groove wall extends outwardly to form a mass block guide beam, and the end of the mass block guide beam away from the groove wall is connected to the connecting beam anchor point, and the first connecting beam is located in the groove and bends and extends along the groove direction.

[0015] Preferably, the driving member is parallel to the Z mass block, and the outer wall of the driving member close to one end of the Z mass block extends on both sides to form a first flexible beam, and the end of the first flexible beam away from the driving member is connected to the Z mass block, and the first flexible beam is located in the distance between the outer wall of the driving member and the Z mass block.

[0016] Preferably, the Z detection decoupling member is in the shape of a frame and is parallel to the Z mass block. The Z detection decoupling member is arranged on the outside of the Z mass block and is separated from the Z mass block to form a narrow gap. The outer walls at both ends of the bottom corners of the Z detection decoupling member extend outward to form a third connecting beam connected to the Z mass block. The third connecting beam is located within the spacing between the Z detection decoupling member and the Z mass block. The base also includes decoupling member anchor points located within the spacing between the Z detection decoupling member and the Z mass block and respectively located at both ends of the Z mass block. Second flexible beams having bending portions and connected to the decoupling member anchor points extend outward from both sides of the Z detection decoupling member.

[0017] Preferably, the base also includes side anchor points, and third flexible beams extend from both sides of the top of the Z detection decoupling component, the middle of which is connected to the side anchor points, and a bending portion extends from the middle of the third flexible beam toward a groove opened inside the side anchor points.

[0018] Preferably, a lateral gap is formed at one end of the X mass block and the Y mass block away from the coupling structure, and the base bottom further comprises an intermediate structure spaced apart at a side of the X mass block and the Y mass block away from the coupling structure, and a lateral flexible beam is formed extending from the lateral gap and connected to the intermediate structure.

[0019] Preferably, a driving transducer is arranged in the driving member, an out-of-plane transducer is arranged in the X mass block, a Y-plane detection transducer is arranged in the Y mass block, and a Z-plane detection transducer is arranged in the Z mass block.

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

[0021] 1. The gyro sensitive mass and detection electrodes are symmetrically arranged to facilitate differential detection;

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

[0023] 3. The three-axis detection modes of the gyroscope xyz can all achieve anti-phase vibration, so the gyroscope differential detection can be realized, which is effectively immune to the influence of acceleration shock and orthogonal error;

[0024] 4. The x, y mass blocks are elastically connected to the anchor points through a decoupling structure, which effectively reduces the coupling between different modal motions of the mass blocks, reduces the displacement of the non-moving mass blocks, and reduces the orthogonal error. This is beneficial to the bias stability of the sensor;

[0025] 5. The z detection mass is connected through a coupling beam, which effectively suppresses the parasitic mode of detection and improves the detection accuracy of gyro 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 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 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 MEMS gyroscope of the present invention;

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

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

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

[0035] Fig. 9 It is a detection mode schematic diagram of the MEMS gyroscope Y-axis angle detection principle 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 , a fully decoupled three-axis MEMS gyroscope includes a substrate 1, a sensor unit 2 elastically connected to the substrate 1, and a driving unit 3 coupled to the sensor unit 2 and driving the sensor unit 2 to move, characterized in that:

[0038] The substrate 1 includes a coupling anchor point 11 located at the center of a rectangle and a coupling structure 12 elastically connected to the coupling anchor point 11;

[0039] The driving unit 3 includes four driving members 31 respectively located at the four corners of the rectangle and elastically connected to the base 1. The four driving members 31 are all frame-shaped. The four driving members 31 are arranged in a ring around the coupling anchor point 11 and are symmetrically arranged. A gap is formed between adjacent driving members 31.

[0040] The sensing unit 2 includes two X mass blocks 21 symmetrically arranged in two opposite making way intervals and elastically connected to the coupling structure 12 and the driving member 31, two Y mass blocks 22 symmetrically arranged in another two opposite making way intervals and elastically connected to the coupling structure 12 and the driving member 31, four Z mass blocks 23 elastically connected to adjacent driving members 31 and located at the four corners of the rectangle, and four Z detection decoupling members 4 elastically connected to adjacent Z mass blocks 23 and arranged around the rectangle, and adjacent Z detection decoupling members 4 are elastically connected.

[0041] Among them, the coupling structure 12 includes an inner coupling ring 121 sleeved outside the coupling anchor point 11, and an outer coupling ring 122 sleeved outside the inner coupling ring 121, the inner side of the inner coupling ring 121 extends along a center line direction of the rectangle to form two inner coupling beams 131 connected to the coupling anchor point 11, and the inner side of the outer coupling ring 122 extends along the straight line direction perpendicular to the two inner coupling beams 131 to form two outer coupling beams 132 connected to the inner coupling ring 121.

[0042] Among them, the X mass block 21 and the Y mass block 22 extend toward the outer coupling ring 122 near the corresponding coupling structure 12 to form a first connecting beam 141 with a bending portion, and the end of the first connecting beam 141 away from the driving member 31 is connected to the outer wall of the corresponding outer coupling ring 122.

[0043] The base 1 further includes a connecting beam anchor 17 located between the coupling structure 12, the X mass block 21, the Y mass block 22 and the driving member 31. The outer walls of the two corners of one end of the driving member 31 close to the connecting beam anchor 17 extend outward to form a second connecting beam 142. The end of the second connecting beam 142 away from the driving member 31 is connected to the connecting beam anchor 17. The second connecting beam 142 is located in the distance between the outer wall of the driving member 31 and the connecting beam anchor 17.

[0044] Among them, grooves are respectively opened on both sides of one end of the X mass block 21 and the Y mass block 22 close to the connecting beam anchor point 17, and the groove wall extends outward to form a mass block guide beam 15, and the end of the mass block guide beam 15 away from the groove wall is connected to the connecting beam anchor point 17, and the first connecting beam 141 is located in the groove and bends and extends along the direction of the groove.

[0045] Among them, the driving member 31 is embedded in the inner side of the Z mass block 23, and the outer wall of the driving member 31 at one end close to the Z mass block 23 extends on both sides to form a first flexible beam 161, and the end of the first flexible beam 161 away from the driving member 31 is connected to the Z mass block 23, and the first flexible beam 161 is located in the distance between the outer wall of the driving member 31 and the Z mass block 23.

[0046] Among them, the Z detection decoupling component 4 is in the shape of a frame, and its appearance matches the Z mass block 23. The Z detection decoupling component 4 is arranged on the outside of the Z mass block 23 and is separated from the Z mass block 23 to form a narrow gap. The outer walls at both ends of the bottom corners of the Z detection decoupling component 4 extend outward to form a third connecting beam 143 connected to the Z mass block 23. The third connecting beam 143 is located in the distance between the Z detection decoupling component 4 and the Z mass block 23. The base also includes a decoupling component anchor point 18 located in the distance between the Z detection decoupling component 4 and the Z mass block 23 and respectively located at both ends of the Z mass block 23. Second flexible beams 162 with bending portions and connected to the decoupling component anchor points 18 extend outward from both sides of the Z detection decoupling component 4.

[0047] Among them, the base 1 also includes a side anchor point 191 located within the spacing between the Z mass block 23 and the X mass block 21, or within the spacing between the Z mass block 23 and the Y mass block 22, and the third flexible beam 163 connected to the side anchor point 191 in the middle is extended from both sides of the top of the Z detection decoupling component 4, and a bending portion is extended from the middle of the third flexible beam 163 to the groove opened inside the side anchor point 191, and two fourth flexible beams 164 of the side anchor point 191 are extended from both sides of the driving component 31 in the direction of the spacing between the Z mass block 23 and the X mass block 21 or the Y mass block 22.

[0048] A lateral gap is formed at one end of the X mass block 21 and the Y mass block 22 away from the coupling structure 12, and the substrate 1 further comprises an intermediate structure 192 spaced apart at one side of the X mass block 21 and the Y mass block 22 away from the coupling structure 12, and the lateral gap of the X mass block 21 and the Y mass block 22 extends to form a lateral flexible beam 165 connected to the intermediate structure 192.

[0049] The driving member 31 is provided with a driving transducer, the X mass block 21 is provided with an out-of-plane transducer, the Y mass block 22 is provided with a Y-plane detection transducer, and the Z mass block 23 is provided with a Z-plane detection transducer.

[0050] 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 2The 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 transducers and the Y detection surface transducers are symmetrically set on the X / Y mass blocks. The Z detection surface transducer is embedded in the rectangular frame of the decoupling mass block.

[0051] 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.

[0052] 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.

[0053] 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 5 It 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 translates in the horizontal direction within the plane, and in the second mode, the Z mass block translates in the vertical direction 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 of 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 of the present invention to generate vibration with the Z-axis detection modal vibration type. Finally, by detecting the vibration displacement of the gyroscope of the present invention along the y-axis direction, the size of the angular velocity ω can be obtained.

[0054] 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 7It 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 the vertical swing of the X / Y mass block; the second mode is the out-of-plane swing mode of the X / Y mass block. The gyroscope is driven to vibrate in a driving mode shape 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 vibrations with an X-axis detection mode shape. 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.

[0055] 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 the horizontal swing of the X / Y mass block, and the second mode is the out-of-plane swing mode of the X / Y mass block. 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.

[0056] 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.

[0057] 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 fully decoupled 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 substrate comprises a coupling anchor point located at the center of a rectangle and a coupling structure elastically connected to the coupling anchor point; the coupling structure comprises an inner coupling ring sleeved outside the coupling anchor point and an outer coupling ring sleeved outside the inner coupling ring, the inner side of the inner coupling ring extends along a center line of the rectangle to form two inner coupling beams connected to the coupling anchor point, and the inner side of the outer coupling ring extends along a straight line perpendicular to the two inner coupling beams to form two outer coupling beams connected to the inner coupling ring; 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 base, the four driving members are all frame-shaped, the four driving members are arranged in a ring around the coupling anchor point and are symmetrically arranged, and a gap is formed between adjacent driving members; The sensing unit includes two X mass blocks symmetrically arranged in two opposite making way intervals and elastically connected to the coupling structure and the driving member, two Y mass blocks symmetrically arranged in another two opposite making way intervals and elastically connected to the coupling structure and the driving member, four Z mass blocks elastically connected to adjacent driving members and located at four corners of the rectangle, and four Z detection decoupling members elastically connected to adjacent Z mass blocks and arranged around the rectangle, and adjacent Z detection decoupling members are elastically connected.

2. The fully decoupled three-axis MEMS gyroscope according to claim 1, characterized in that: The X mass block and the Y mass block are close to the corresponding coupling structure and extend toward the outer coupling ring to form a first connecting beam with a bending portion. The end of the first connecting beam away from the driving member is connected to the outer wall of the corresponding outer coupling ring.

3. The fully decoupled three-axis MEMS gyroscope according to claim 2, characterized in that: The base also includes a connecting beam anchor point, and the outer walls of the two corners of one end of the driving member close to the connecting beam anchor point extend outward to form a second connecting beam, and the end of the second connecting beam away from the driving member is connected to the connecting beam anchor point, and the second connecting beam is located in the distance between the outer wall of the driving member and the connecting beam anchor point.

4. The fully decoupled three-axis MEMS gyroscope according to claim 3, characterized in that: The X mass block and the Y mass block each have a groove, and the groove wall extends outward to form a mass block guide beam. The end of the mass block guide beam away from the groove wall is connected to the connecting beam anchor point, and the first connecting beam is located in the groove and bends and extends along the groove direction.

5. The fully decoupled three-axis MEMS gyroscope according to claim 1, characterized in that: The driving member is parallel to the Z mass block, and the outer wall of the driving member close to one end of the Z mass block extends on both sides to form a first flexible beam. The end of the first flexible beam away from the driving member is connected to the Z mass block, and the first flexible beam is located in the distance between the outer wall of the driving member and the Z mass block.

6. The fully decoupled three-axis MEMS gyroscope according to claim 5, characterized in that: The Z detection decoupling member is in the shape of a frame and is arranged in parallel with the Z mass block. The Z detection decoupling member is arranged on the outside of the Z mass block and is separated from the Z mass block to form a narrow gap. The outer walls at both ends of the bottom corners of the Z detection decoupling member extend outward to form a third connecting beam connected to the Z mass block. The third connecting beam is located in the distance between the Z detection decoupling member and the Z mass block. The base also includes a decoupling member anchor point located in the distance between the Z detection decoupling member and the Z mass block and respectively located at both ends of the Z mass block. Second flexible beams with bending portions and connected to the decoupling member anchor points extend outward from both sides of the Z detection decoupling member.

7. The fully decoupled three-axis MEMS gyroscope according to claim 1, characterized in that: The base also includes side anchor points, and third flexible beams with the middle connected to the side anchor points extend from both sides of the top of the Z detection decoupling component, and a bending portion extends from the middle of the third flexible beam to a groove opened inside the side anchor point.

8. The fully decoupled three-axis MEMS gyroscope according to claim 7, characterized in that: A lateral gap is formed at one end of the X mass block and the Y mass block away from the coupling structure, and the substrate further comprises an intermediate structure spaced apart at one side of the X mass block and the Y mass block away from the coupling structure, and both the X mass block and the Y mass block extend toward the lateral gap to form a lateral flexible beam connected to the intermediate structure.

9. The fully decoupled three-axis MEMS gyroscope according to claim 1, characterized in that: A driving transducer is arranged in the driving member, an out-of-plane transducer is arranged in the X mass block, a Y-plane detection transducer is arranged in the Y mass block, and a Z-plane detection transducer is arranged in the Z mass block.

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