A motion-decoupled MEMS gyroscope sensor structure

Abstract

The application provides a motion decoupling MEMS gyroscope sensor structure, and solves the adverse effects caused by the motion coupling between driving masses and detecting masses and the rotation mode coupling between the driving masses in the existing gyroscope sensor structure. In the application, the driving masses and the detecting masses are connected by a combined decoupling beam, when an angular velocity signal is input, the driving masses drive the detecting masses to move, the detecting masses are stably detected by the detecting axis electrodes, and closed-loop control is realized by using a force feedback control signal, the transmission of the Coriolis force when the angular velocity is input is realized, the detecting masses are driven to move to realize the measurement of the angular velocity. The combined decoupling beam structure not only realizes the purpose that the driving masses drive the detecting masses to move, but also avoids the influence on the detecting masses, and a good motion decoupling effect is achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of inertial sensors, and particularly relates to a motion-decoupled MEMS gyroscope sensor structure. BACKGROUND

[0002] The MEMS gyroscope sensor structure is a core part of the MEMS gyroscope and serves as an execution structure for measuring the rotation angular velocity signal of a carrier. Under the control of a control circuit, the internal structure of the MEMS gyroscope sensor structure will change in position under the action of the Coriolis force when the angular velocity signal acts, and then the control circuit calculates the angular velocity signal.

[0003] The existing MEMS gyroscope has certain motion coupling between the driving mass and the detection mass (also referred to as the sensitive mass) of the gyroscope sensor structure, so that the driving shaft motion is superimposed on the detection shaft, resulting in a large error signal. Meanwhile, the coupling between the driving masses is in the form of rotation, which brings about large energy loss and reduces the driving stability. Influenced by multiple adverse factors, the precision of the MEMS gyroscope is difficult to improve, the anti-interference capability is poor, and the use scenarios are limited.

[0004] Therefore, it is necessary to optimize the MEMS gyroscope sensor structure. SUMMARY

[0005] The application aims to solve the adverse effects caused by the motion coupling between the driving mass and the detection mass and the coupling between the driving masses in the form of rotation in the existing gyroscope sensor structure, and provides a motion-decoupled MEMS gyroscope sensor structure, which aims to eliminate the influence of the driving shaft motion on the detection shaft, reduce errors, reduce energy consumption, improve driving stability, and thus improve the precision and anti-interference capability of the MEMS gyroscope and expand the use scenarios.

[0006] The concept of the application is:

[0007] In view of the influence caused by the motion coupling between the driving mass and the detection mass and the coupling between the driving masses in the form of rotation mentioned in the background, the researchers change the coupling mode between the driving mass and the detection mass and between the driving masses, so as to eliminate the motion coupling between the driving mass and the detection mass and change the coupling mode between the driving masses. For this purpose, the application introduces a combined decoupling beam to connect the driving mass, the detection mass and the driving mass, realizes the transmission of the Coriolis force when the angular velocity input, eliminates the mutual influence between the driving shaft motion and the detection shaft motion, makes the driving shaft and the detection shaft move independently, and effectively improves the precision and anti-interference capability of the gyroscope.

[0008] To achieve the above-mentioned purpose, the technical solution provided by the application is:

[0009] A motion decoupled MEMS gyroscope sensor structure, characterized in that:

[0010] It comprises four groups of mass units, four T-shaped motion coupling beams and a cross-shaped motion coupling beam.

[0011] The four groups of mass units are arranged in a quadrilateral distribution and symmetrically arranged in pairs. The outer sides between the two adjacent groups of mass units are fixedly connected by a T-shaped motion coupling beam, and the center position of the combined four groups of mass units is fixedly connected by a cross-shaped motion coupling beam.

[0012] Each group of mass units comprises a dependent mass, two drive masses, two detection masses, a drive mass drive comb structure, a drive mass detection comb structure, a detection mass detection comb structure and a detection mass feedback comb structure.

[0013] A rectangular space is formed in each of the four directions of the dependent mass, and the four rectangular spaces are arranged in a cross shape opposite to each other.

[0014] A drive mass is arranged in each of the pair of opposite rectangular spaces, and the two drive masses are connected to the dependent mass through a combined decoupling beam and are symmetrically arranged with respect to the center of the dependent mass. A drive mass drive comb structure is mounted on one of the drive masses, and a drive mass detection comb structure is mounted on the other drive mass. The drive comb structure is matched with the fixed comb structure to form a capacitor pair, and the drive comb capacitor pair adopts a slider film capacitor structure, the comb tooth spacing size is 1-5um, and the comb teeth are equidistantly distributed.

[0015] A detection mass is arranged in each of the other pair of opposite rectangular spaces, and the two detection masses are connected to the dependent mass through a combined decoupling beam and are symmetrically arranged with respect to the center of the dependent mass. A detection mass detection comb structure is mounted on one of the detection masses, and a detection mass feedback comb structure is mounted on the other detection mass. The detection comb structure is matched with the fixed comb structure to form a capacitor pair, and the detection comb capacitor pair adopts a pressure film capacitor structure, the small comb tooth spacing size is 1-5um, and the large comb tooth spacing size is 2-5 times the small comb tooth spacing size.

[0016] The combined decoupling beam comprises a Y-shaped beam, a decoupling mass and a decoupling beam connected in sequence. The Y-shaped beam is connected to the drive mass or the detection mass at one end, and the decoupling beam is connected to the dependent mass at the other end.

[0017] The four T-shaped motion coupling beams and one cross-shaped motion coupling beam assemble four groups of mass body units together through decoupling mass bodies in each combined decoupling beam, and the motion coupling beams connect the decoupling mass bodies so that the motion coupling between the decoupling mass bodies is linear movement; after the four groups of mass body units are assembled, the directions of the center lines of the two drive mass bodies in each group of mass body units are parallel to each other and parallel to the direction of one arm of the cross-shaped motion coupling beam; the directions of the center lines of the two detection mass bodies in each group of mass body units are parallel to each other and parallel to the direction of the other arm of the cross-shaped motion coupling beam.

[0018] The drive mass body, the detection mass body and the related mass body each have two directions of freedom of motion, that is, each can move in two axial directions.

[0019] Further, the two ends of the cross arm of the T-shaped motion coupling beam are fixedly connected with the adjacent two groups of mass body units, and the two side surfaces of the vertical arm of the T-shaped beam are fixedly connected with the adjacent two groups of mass body units through connecting protrusions.

[0020] The two side surfaces of each of the four arms of the cross-shaped motion coupling beam are fixedly connected with one group of mass body units through connecting protrusions, and the four arms of the cross-shaped motion coupling beam are respectively flush with the vertical arms of the four T-shaped motion beams.

[0021] Further, the drive mass body is supported by a plurality of groups of symmetrically distributed drive beams.

[0022] The plurality of groups of drive beams are uniformly distributed around the drive mass body, and have consistent structural sizes, so as to ensure that the stiffness of each axial direction of the drive beams is consistent.

[0023] One end of the drive beam is fixed on a substrate or an outer frame, and the other end provides support for the drive mass body.

[0024] Further, the drive beam is a combined beam structure or a single cantilever beam structure, and the relationship between the beams is parallel, that is, the plurality of groups of drive beams are combined in a parallel manner, so as to provide the drive mass body with two directions of freedom of motion; and the combination mode of a single drive beam is series or parallel.

[0025] Further, the detection mass body is supported by a plurality of groups of symmetrically distributed detection beams.

[0026] The plurality of groups of detection beams are uniformly distributed around the detection mass body, and have consistent structural sizes, so as to ensure that the stiffness of each axial direction of the detection beams is consistent.

[0027] One end of the detection beam is fixed on a substrate or an outer frame, and the other end provides support for the detection mass body.

[0028] Further, the detection beams are combined beam structures or single cantilever beam structures, and the relationship between the beams is parallel, that is, multiple detection beams are combined in parallel, so that the freedom of movement of the detection mass in two directions can be provided; and the combination of single detection beams is in series or in parallel.

[0029] Further, the decoupling beams are single cantilever beams or folded beams.

[0030] The T-shaped motion coupling beams and the cross-shaped motion coupling beams are combined beams, and include single cantilever beams and folded beams.

[0031] The width of the decoupling beams is 2-10 um, and the length is 20-50 times the width.

[0032] The width of the Y-shaped beam structure is 2-10 um, and the length is 2-5 times the width.

[0033] Further, the width of the driving beam is 2-10 um, and the length is 50-100 times the width.

[0034] The width of the detection beam is 2-10 um, and the length is 50-100 times the width.

[0035] Meanwhile, the application also provides a MEMS gyroscope using the above-mentioned motion decoupling MEMS gyroscope sensor structure as a core component.

[0036] Principle of the application:

[0037] The sensor structure driving mass is stably driven by the driving shaft electrode, and the motion of the associated mass is driven by the combined decoupling beam, so that it is in differential high-frequency oscillation. When an angular velocity signal is input, the associated mass produces orthogonal axis motion under the action of the Coriolis force, and drives the detection mass to move along the orthogonal axis. The orthogonal motion of the detection mass causes the capacitance value of the detection comb tooth capacitor pair to change, and the change of the capacitor is stably detected by the detection shaft electrode pair and forms a feedback voltage through the control circuit, which is applied to the detection shaft feedback electrode pair, so that the detection mass is in a closed-loop control state. The T-shaped motion coupling beam and the cross-shaped motion coupling beam connect the decoupling masses on different combined decoupling beams, so that the coupling process between the driving motions presents linear movement, greatly reduces the interference to the driving motion, and improves the driving stability. The combined decoupling beam connects the associated mass, the driving mass and the detection mass, realizes the transmission of the Coriolis force when the angular velocity is input, and eliminates the mutual influence between the out-of-axis motion and the detection axis motion, so that the driving shaft and the detection shaft move independently, and the precision and anti-interference ability of the gyroscope are effectively improved.

[0038] Advantages of the application:

[0039] 1. The invention relates to a mass body connected to a driving mass body and a detection mass body through a combined decoupling beam. When an angular velocity signal is input, the connected mass body drives the detection mass body to move, and the detection axis electrode stabilizes the detection and realizes closed-loop control using a force feedback control signal, realizes the transmission of the Coriolis force when the angular velocity is input, drives the detection mass body to move to realize the measurement of the angular velocity. The combined decoupling beam structure not only realizes the purpose of driving the connected mass body to drive the movement, but also avoids the influence on the detection mass body, and achieves good motion decoupling effect. The motion coupling beam pulls the decoupling mass body, so that the motion coupling between the driving mass bodies is in moving motion rather than rotating motion, greatly reduces the driving motion coupling energy loss, and effectively improves the motion stability.

[0040] 2. The sensor structure of the invention realizes complete decoupling of driving motion and detection motion by using a combined decoupling beam. When the MEMS gyroscope control circuit drives the differential operation, the precision and anti-interference ability of the MEMS gyroscope can be effectively improved. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 It is a schematic diagram of a gyroscope sensor structure;

[0042] Figure 2 It is a schematic diagram of a driving shaft structure;

[0043] Figure 3 It is a schematic diagram of a detection shaft structure;

[0044] Figure 4 It is a schematic diagram of a combined decoupling beam structure;

[0045] Figure 5 It is a schematic diagram of a T-shaped motion coupling beam structure;

[0046] In the figure: 1-driving mass body, 2-driving beam, 3-connected mass body, 4-combined decoupling beam, 5-detection mass body, 6-detection beam, 7-driving mass driving comb structure, 8-driving mass detection comb structure, 9-detection mass detection comb structure, 10-detection mass feedback comb structure, 11-T-shaped motion coupling beam, 12-Y-shaped beam, 13-decoupling mass body, 14-decoupling beam, 15-cross-shaped motion coupling beam. DETAILED DESCRIPTION

[0047] The content of the invention is further described in detail in combination with the drawings and specific embodiments:

[0048] As Figure 1As shown, a motion decoupling MEMS gyroscope structure includes four groups of mass units, four T-shaped motion coupling beams and a cross-shaped motion coupling beam; the four groups of mass units are arranged in a four-cornered distribution and symmetrically arranged in pairs; the outer sides between the two adjacent groups of mass units are fixedly connected through a T-shaped motion coupling beam, and the center position of the combined four groups of mass units is fixedly connected through the cross-shaped motion coupling beam.

[0049] Each group of mass units includes a dependent mass, two drive masses, two detection masses, a drive mass drive comb structure, a drive mass detection comb structure, a detection mass detection comb structure and a detection mass feedback comb structure. Four rectangular spaces are formed in the four directions of the dependent mass, and the four rectangular spaces are cross-distributed in pairs.

[0050] A pair of oppositely arranged rectangular spaces are arranged with drive masses, and the two drive masses are symmetrically arranged with respect to the center of the dependent mass. Figure 2 As shown, each drive mass is connected to the dependent mass through a combined decoupling beam; the drive mass is supported by a plurality of symmetrically distributed drive beams; the plurality of drive beams are uniformly distributed around the drive mass, and have consistent structure sizes to ensure consistent stiffness of the drive beams in each axis; wherein one end of the drive beam is fixed on the substrate or the outer frame, and the other end provides support for the drive mass; the drive beam is a combined beam structure or a single cantilever beam structure, and the relationship between the beams is parallel, which can provide the drive mass with the freedom of movement in two directions; and the combined mode of a single drive beam is series or parallel. The width of the drive beam is 2-10um, and the length is 50-100 times the width. The drive mass drive comb structure and the drive mass detection comb structure are symmetrically fixed on the two drive masses, and the specific positions are: the drive mass drive comb structure is fixed with the drive mass on the outer side, and the drive mass detection comb structure is fixed with the drive mass on the inner side; in addition, the drive comb structure matches with the fixed comb structure (not shown in the figure, which is arranged at the opposite position of the drive comb structure and connected with the substrate or the anchor point) to form a capacitor pair, and the drive comb capacitor pair adopts a slide film capacitor structure, the comb tooth spacing size is 1-5um, and the comb teeth are equally distributed.

[0051] Another pair of oppositely arranged rectangular spaces are arranged with detection masses, and the two detection masses are symmetrically arranged with respect to the center of the dependent mass. Figure 3As shown, each detection mass is connected by a combined decoupling beam and a dependent mass; the detection mass is supported by multiple sets of symmetrically distributed detection beams; the multiple sets of detection beams are uniformly distributed around the detection mass and have consistent structural dimensions, ensuring consistent axial stiffness of the detection beams; one end of the detection beam is fixed to the substrate or outer frame, and the other end provides support for the detection mass; the detection beam is a combined beam structure or a single cantilever beam structure, and the relationship between the beams is parallel, which can provide the detection mass with two degrees of freedom of movement in two directions; and the combination of individual detection beams is in series or parallel. The width of the detection beam is 2-10um, and the length is 50-100 times the width. The detection mass detection comb structure and the detection mass feedback comb structure are symmetrically fixed to the two detection masses, and the specific positions are: the detection mass detection comb structure is fixed to the outer detection mass, and the detection mass feedback comb structure is fixed to the inner detection mass; in addition, the detection comb structure matches the fixed comb structure (not shown in the figure, which is arranged at the opposite position of the detection comb structure and connected to the substrate or anchor point) to form a capacitor pair, and the detection comb capacitor pair adopts a film pressing capacitor structure, and the small gap size of the comb tooth is 1-5um, and the large gap size is 2-5 times the small gap size.

[0052] As shown in Figure 4 , the combined decoupling beam includes a Y-shaped beam, a decoupling mass, and a decoupling beam connected in sequence; wherein the Y-shaped beam is connected with the drive mass 1 or the detection mass, and the decoupling beam is connected with the dependent mass; wherein the decoupling beam is a single cantilever beam or a folded beam, and the width of the decoupling beam is 2-10um, and the length is 20-50 times the width; the width of the Y-shaped beam structure is 2-10um, and the length is 2-5 times the width.

[0053] Four T-shaped motion coupling beams and one cross-shaped motion coupling beam assemble four groups of mass units through the decoupling masses in each combined decoupling beam. After the four groups of mass units are assembled, the center lines of the two drive masses in each group of mass units are parallel to each other, and parallel to the direction of one arm of the cross-shaped motion coupling beam; the center lines of the two detection masses in each group of mass units are parallel to each other, and parallel to the direction of the other arm of the cross-shaped motion coupling beam.

[0054] As shown in Figure 5 , the two ends of the horizontal arm of the T-shaped motion coupling beam are fixedly connected with the adjacent two groups of mass units, and the two sides of the vertical arm of the T-shaped beam are fixedly connected with the adjacent two groups of mass units through the connecting protrusions; as shown in Figure 1 , the two sides of each of the four arms of the cross-shaped motion coupling beam are fixedly connected with a group of mass units through the connecting protrusions, and the four arms of the cross-shaped motion coupling beam are respectively aligned with the vertical arms of the four T-shaped motion beams. The two kinds of motion coupling beams are combined beams, which include single cantilever beams and folded beams and other forms.

[0055] Through the above design, the driving mass, the detection mass and the entrainment mass all have two degrees of freedom of movement in two directions, that is, they can move in two axial directions.

[0056] The above merely provides a specific implementation of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present application, and these modifications or replacements shall be encompassed within the protection scope of the present application.

Claims

1. A motion-decoupled MEMS gyroscope sensor structure, characterized by: It includes four groups of mass units, four T-shaped motion coupling beams and one cross-shaped motion coupling beam; The four groups of mass units are distributed in four corners and arranged symmetrically in pairs; the outer sides of two adjacent groups of mass units are fixedly connected by a T-shaped motion coupling beam, and the center position of the four groups of mass units after combination is fixedly connected by a cross-shaped motion coupling beam; Each group of mass units includes an involved mass, two driving mass bodies, two detection mass bodies, a driving mass driving comb structure, a driving mass detection comb structure, a detection mass detection comb structure, and a detection mass feedback comb structure; A rectangular space is opened at each of the four directions of the involved mass body, and the four rectangular spaces are arranged in a cross shape with two of them facing each other; A pair of oppositely arranged rectangular spaces are both provided with driving mass bodies, and the two driving mass bodies are connected to the involved mass body via a combined decoupling beam and are symmetrical relative to the center of the involved mass body; A driving mass driving comb structure is installed on one of the driving mass bodies, and a driving mass detection comb structure is installed on the other driving mass body; Another pair of oppositely arranged rectangular spaces are each provided with a proof mass body, the two proof mass bodies being connected to the involved mass body via a combined decoupling beam and being symmetrical relative to the center of the involved mass body; a proof mass detection comb structure is installed on one of the proof mass bodies, and a proof mass feedback comb structure is installed on the other proof mass body; The combined decoupling beam comprises a Y-shaped beam, a decoupling mass body and a decoupling beam connected in sequence; wherein the end of the Y-shaped beam is connected to the driving mass body or the detection mass body, and the end of the decoupling beam is connected to the involved mass body; The four T-shaped motion coupling beams and one cross-shaped motion coupling beam assemble four groups of mass body units together through the decoupling mass bodies in each combined decoupling beam; after the four groups of mass body units are assembled, the directions of the center lines of the two driving mass bodies in each group of mass body units are parallel to each other and parallel to the direction of one arm in the cross-shaped motion coupling beam; the directions of the center lines of the two detection mass bodies in each group of mass body units are parallel to each other and parallel to the direction of the other arm in the cross center beam.

2. The motion-decoupled MEMS gyroscope sensor structure according to claim 1, characterized in that: The two ends of the horizontal arm of the T-shaped motion coupling beam are fixedly connected to the two adjacent groups of mass body units, and the two side surfaces of the vertical arm of the T-shaped beam are fixedly connected to the two adjacent groups of mass body units through connecting protrusions; The two side surfaces of each of the four arms of the cross-shaped motion coupling beam are fixedly connected to a group of mass body units through connecting protrusions, and the four arms of the cross-shaped motion coupling beam are flush with the vertical arms of the four T-shaped motion beams respectively.

3. The motion-decoupled MEMS gyroscope sensor structure according to claim 1 or 2, characterized in that: The driving mass body is supported by multiple groups of symmetrically distributed driving beams; Multiple groups of drive beams are evenly distributed around the drive mass body, and the structural dimensions are consistent, ensuring that the rigidity of the drive beams in all axial directions is consistent; One end of the driving beam is fixed, and the other end provides support force for the driving mass body.

4. The motion-decoupled MEMS gyroscope sensor structure according to claim 3, characterized in that: The driving beam is a composite beam structure or a single cantilever beam structure, and the relationship between the beams is parallel.

5. The motion-decoupled MEMS gyroscope sensor structure according to claim 4, characterized in that: The detection mass body is supported by multiple groups of symmetrically distributed detection beams; Multiple groups of detection beams are evenly distributed around the detection mass body, and the structural dimensions are consistent to ensure that the stiffness of the detection beams in each axial direction is consistent; One end of the detection beam is fixed, and the other end provides support force for the detection mass body.

6. The motion-decoupled MEMS gyroscope sensor structure according to claim 5, characterized in that: The detection beam is a combined beam structure or a single cantilever beam structure, and the relationship between the beams is parallel.

7. The motion-decoupled MEMS gyroscope sensor structure according to claim 1, characterized in that: The decoupling beam is a single cantilever beam or a folded beam; The T-shaped motion coupling beam and the cross-shaped motion coupling beam are both composite beams, including a single cantilever beam and a folded beam; The width of the decoupling beam is 2-10 μm, and the length is 20-50 times the width; The width of the Y-beam structure is 2-10 μm, and the length is 2-5 times the width.

8. The motion-decoupled MEMS gyroscope sensor structure according to claim 5, characterized in that: The width of the driving beam is 2-10 μm, and the length is 50-100 times the width; The detection beam has a width of 2-10 μm and a length of 50-100 times the width.

9. A MEMS gyroscope, characterized in that: The motion-decoupled MEMS gyroscope sensor structure according to any one of claims 1 to 8 is used as a core component.

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