An in-plane sensitive axis micromechanical gyroscope based on motion direction conversion structure

Abstract

The present invention belongs to the technical field of in-plane MEMS gyroscopes and discloses an in-plane sensitive axis micromechanical gyroscope based on a motion direction conversion structure, comprising: a drive frame, a Coriolis mass, a detection frame, a drive spring beam, a detection spring beam, a drive electrode, and a detection electrode; the drive frame and the detection frame are connected together via the Coriolis mass and a conversion structure; the conversion structure is a bracket structure, and the out-of-plane up and down motion under the action of an external force is converted into in-plane planar motion by the bracket structure; the drive frame moves in the plane under the action of the drive electrode; the detection frame also moves in the plane after passing through the conversion structure, and the relative position of the detection electrode and the detection frame is consistent with the drive mode. The conversion structure of the present invention can couple the out-of-plane motion of the in-plane gyroscope to the in-plane motion for detection signal extraction. Such a structure can increase the number of detection comb teeth, thereby improving signal gain.

Description

Technical Field

[0001] The present invention belongs to the technical field of in-plane MEMS gyroscopes, and in particular relates to an in-plane sensitive axis micromechanical gyroscope based on a motion direction conversion structure. Background Art

[0002] Gyroscopes are sensors that measure the rotational motion of a carrier relative to inertial space. They are core components in motion measurement, inertial navigation, guidance and control, and other fields. They have crucial applications in high-end industrial equipment and precision strike weapons, such as aerospace, intelligent robotics, and guided munitions. Currently, gyroscopes primarily include rotor gyroscopes, fiber optic gyroscopes, laser gyroscopes, and micro-electromechanical (MEMS) gyroscopes. Gyroscopes based on micro-electromechanical systems (MEMS) technology offer advantages such as small size, low cost, low power consumption, long life, high reliability, and mass production. They are suitable for use in complex and harsh environments, as well as in applications requiring minimal size and power consumption.

[0003] Micromachined gyros can be categorized as out-of-plane or in-plane based on the orientation of their sensitive axes. An in-plane MEMS gyro, with its sensitive axis in-plane, is a sensor capable of sensing in-plane angular velocity along the X / Y axes. An out-of-plane MEMS gyro, with its sensitive axis out-of-plane, is sensitive to angular velocity along the Z axis. Because both the driving and sensing motions of an out-of-plane MEMS gyro are in-plane, modal decoupling is easier to achieve. However, because the driving or sensing axis of an in-plane gyro lies out-of-plane, its signal-to-noise ratio is limited by the sensing capacitance of the sensing electrodes, resulting in a low signal-to-noise ratio.

[0004] Currently available in-plane gyros are mostly sensitive to out-of-plane motion, also known as flipping. This out-of-plane flipping motion can be used to change the capacitance in two ways. The first is to directly place electrodes on the upper and lower covers of the MEMS chip. The flipping motion generates capacitance by changing the gap between the parallel plate capacitors, thereby outputting an electrical signal. The other is to generate an electrical signal by changing the area between the detection comb teeth caused by the flipping motion, thereby changing the capacitance.

[0005] The existing electrical signal extraction schemes have the following problems: the first scheme has large nonlinearity in the detection capacitance, and the detection capacitance area is limited, which cannot exceed the area of the entire chip. It also requires electrodes to be made on the upper and lower covers, which is a relatively complex process. The second scheme also uses flipping to generate capacitance area changes, thereby generating capacitance changes, but this comb-tooth layout is limited and cannot be arranged in large quantities. In short, both of the above-mentioned capacitance changes generated by flipping motion have their own limitations. Summary of the Invention

[0006] The purpose of the present invention is to provide an in-plane sensitive axis micromechanical gyroscope based on a motion direction conversion structure to solve the problems mentioned in the background technology.

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

[0008] An in-plane sensitive axis micromechanical gyroscope based on a motion direction conversion structure comprises: a motion direction conversion structure 1, and other coupling module units 2 connected to the motion direction conversion structure.

[0009] The motion direction conversion structure 1 includes: a connecting Coriolis mass rod 11, two triangular beams 12,

[0010] The other coupling module units include: a driving frame 21, a Coriolis mass 22, a detection frame 23, a driving spring beam 24, a detection spring beam 25, a driving electrode 26, a detection electrode 27, a decoupling beam 28, a first connecting beam 291, a second connecting beam 292, and a sensitive frame coupling beam 30;

[0011] The gyroscope is bilaterally symmetrical; a first connecting beam is provided on each of the left and right edges of the gyroscope, and the middle portion of the first connecting beam is fixedly connected to the gyroscope substrate;

[0012] The connection relationship on the left side of the gyroscope is as follows: the triangular beam is a beam composed of two sides of a triangle, and the two triangular beams are arranged horizontally symmetrically with the open ends facing inward; two Coriolis mass rods are placed vertically and parallel, and are disconnected in the middle to form an upper beam and a lower beam; the two triangular beams are respectively located on the left and right sides of the two Coriolis mass rods, the upper ends of the two triangular beams are respectively connected to the two lower beams connected to the Coriolis mass rods, and the lower ends of the two triangular beams are respectively connected to the two upper beams connected to the Coriolis mass rods; the other sides of the two upper beams connected to the Coriolis mass rods are connected to the upper left Coriolis mass, and the other sides of the two lower beams connected to the Coriolis mass rods are connected to the lower left Coriolis mass; an upper left drive frame is provided above the upper left Coriolis mass, and a lower left drive frame is provided below the lower left Coriolis mass, and the left and right sides of each Coriolis mass are connected to the left and right sides of the drive frame via a decoupling beam; each drive frame has a rectangular opening on its left and right sides, and a drive spring beam is provided in each rectangular opening; one side of the drive spring beam is fixed to the substrate and the other side is connected to the drive frame; each triangular beam is connected to a detection frame at its vertex; and each detection frame has a detection electrode.

[0013] The detection frames on the outer sides of the left and right planes are connected to the middle parts of the first connecting beams on the left and right sides respectively through the detection spring beams; the two detection frames on the inner sides of the left and right planes are connected through the sensitive frame coupling beam; the upper and lower sides of the first connecting beam are also connected to the two driving frames on that side respectively;

[0014] There is a driving electrode at each corner of the substrate. Comb teeth are provided on the outside of each driving frame to form a comb pair with the driving electrode. The driving electrode generates horizontal static electricity through the comb pair to drive the driving frame to move.

[0015] The right side of the upper left driving frame is connected to the left side of the upper right driving frame through two second connecting beams; the right side of the lower left driving frame is connected to the left side of the lower right driving frame through two second connecting beams.

[0016] Furthermore, the stiffness of the connected Coriolis mass rods is adjusted by adjusting at least one parameter of the cross-sectional shape, length and arrangement position of the connected Coriolis mass rods 11 .

[0017] Furthermore, the driving frame 21 , the Coriolis mass 22 , and the detection frame 23 are all flat structures, and are in the same plane as the connecting Coriolis mass rod 11 , and in an orthogonal plane to the triangular beam 12 .

[0018] Furthermore, the driving frame 21 is used to drive the Coriolis mass 22 to reciprocate in a direction perpendicular to the plane where the gyroscope is located when detecting the mode;

[0019] The driving frame 21 is used to drive the Coriolis mass 22 to reciprocate in a direction perpendicular to the rods connecting the Coriolis masses in the gyro plane in the driving mode.

[0020] Furthermore, the first connecting beam 291 is a lever beam.

[0021] Furthermore, the second connecting beam 292 is an elastic beam, which is used to connect adjacent driving frames 21 .

[0022] Furthermore, the sensitive frame coupling beam 30 is an elastic beam, which is used to connect two adjacent detection frames 23 .

[0023] Furthermore, the detection electrodes adopt a comb-tooth structure, which is a parallel plate with variable area or variable gap.

[0024] The decoupling structure of the present invention not only realizes the decoupling of the in-plane gyroscope driving mode and the detection mode, but also converts the out-of-plane motion into the in-plane motion through the motion direction conversion structure. This structure of the present invention can effectively improve the detection capacitor gain, has a simple structure, obvious effect, and does not introduce displacement in other directions. The process does not require electrodes for the upper and lower cover plates, and a getter can be laid on the upper and lower cover plates to achieve a higher quality factor and further improve the mechanical gain. In short, this new in-plane gyroscope structure that converts out-of-plane motion into in-plane motion can greatly improve the gain of the gyroscope's output signal.

[0025] According to one embodiment of the present invention, the in-plane sensitive axis micromechanical gyroscope is based on the principles of comb-tooth electrostatic drive and detection. It utilizes four symmetrical large-area sensitive masses. Driven by a motion-direction conversion mechanism, the four detection frames exhibit strong anti-interference capabilities. This structure not only offers the advantages of decoupling the drive and detection modes, but also boasts a high signal output gain. The symmetrical structure effectively suppresses machining errors, thereby enhancing the gyroscope's stability.

[0026] According to one solution of the present invention, the unique decoupling structure of the present invention can achieve modal decoupling of the MEMS in-plane gyroscope and realize in-plane detection without the need for applying electrodes with the help of upper and lower cover plates, thereby increasing signal gain. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific implementation scheme of the present invention, the specific drawings of the scheme will be described below.

[0028] Figure 1 2 is a schematic structural diagram of a MEMS in-plane gyroscope according to an embodiment of the present invention;

[0029] Figure 2 It is a structural schematic diagram of a motion conversion component according to an embodiment of the present invention;

[0030] Figure 3 2. It is a schematic diagram of the substrate anchor point structure of a MEMS in-plane gyroscope according to an embodiment of the present invention;

[0031] Figure 4 is a motion diagram of a gyro driving mode according to an embodiment of the present invention;

[0032] Figure 5 is a motion diagram of a gyro sensitive mode according to an embodiment of the present invention;

[0033] Attachment Figure 1 In the figure, 21-driving frame, 22-Coriolis mass, 23-detection frame, 24-driving spring beam, 25-detection spring beam, 26-driving electrode, 27-detection electrode, 28-decoupling beam, 291-first connecting beam, 292-second connecting beam, 30-sensitive frame coupling beam.

[0034] Attachment Figure 2 Schematic diagram of the motion conversion component structure, 11-connecting Coriolis mass rod, 12-triangular beam.

[0035] Attachment Figure 3 are anchor points on the substrate, 3-first anchor point, 4-second anchor point, 5-third anchor point, 6-fourth anchor point. DETAILED DESCRIPTION

[0036] This section is an embodiment of the present invention, which is used to explain and illustrate the technical solutions of the present invention.

[0037] The present invention is described in further detail below in conjunction with the embodiments:

[0038] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0039] Combine Figure 1 and Figure 2 As shown, according to one embodiment of the present invention, an in-plane sensitive axis micromechanical gyroscope based on a motion direction conversion structure includes: a motion direction conversion structure 1 and other coupling unit modules 2. In this embodiment, the other coupling unit modules 2 include: a drive frame 21, a Coriolis mass 22, a detection frame 23, a drive spring beam 24, a detection spring beam 25, a drive electrode 26, a detection electrode 27, a decoupling beam 28, a drive frame coupling beam 29, and a sensitive frame coupling beam 30; wherein the drive frame 21 and the Coriolis mass block 22 are connected by a coupling beam. The Coriolis mass block 22 and the detection frame 23 are connected by the motion direction conversion structure 1; the Coriolis mass beam 11 connected to the motion direction conversion structure 1 can move in an out-of-plane direction under the action of an external force, driving the triangular beam structure 12 to generate in-plane translation, thereby achieving the purpose of motion direction conversion.

[0040] In this embodiment, the driving frame 21 performs reciprocating motion in the plane as the main motion bearing structure. The motion principle is to apply voltages of the same amplitude and opposite phases to the left and right driving electrodes of the structure, thereby generating electrostatic forces in opposite directions. Under the action of the electrostatic forces, the entire structure of the in-plane gyroscope resonates in the driving mode, as shown in FIG. Figure 3 As shown. When the entire structure resonates in the driving mode, the driving frame 21 drives the Coriolis mass 22 to produce resonant motion through the connected decoupling beam 28. At this time, if there is an external angular velocity input, the Coriolis mass 22 will generate an out-of-plane Coriolis force. Under the action of the Coriolis force, the Coriolis mass 22 produces out-of-plane up and down motion. The Coriolis mass 22 will drive the connected Coriolis mass beam 11 to move up and down out of the plane. The movement of the connected Coriolis mass beam 11 is converted to left and right motion in the plane through the triangular beam 12. The other end of the triangular beam 12 will also drive the detection frame 23 to move left and right in the plane. Through this series of motion decoupling, the traditional out-of-plane up and down motion detection electrodes of the in-plane gyroscope can be converted to in-plane detection electrodes. The advantage of this is that the position of the upper and lower covers does not need to be set to set electrodes, ensuring the area of the getter inside the gyroscope, thereby producing a gyroscope with a high quality factor. In-plane detection can also increase the number of detection electrodes, thereby achieving higher gain signal detection and thus a higher signal-to-noise ratio.

[0041] The structural layout of this embodiment is a layout of four mass blocks, which can better differentiate the signals, thereby filtering out useless signals related to the external environment and only outputting signals related to the angular velocity.

[0042] In this embodiment, detection electrode 27 is positioned on one side of detection frame 23. It utilizes a comb-teeth structure and can be either a variable-area or variable-gap parallel plate. Planar motion of the detection frame causes changes in the parallel-plate capacitance structure, generating an electrical signal and enabling detection. In this embodiment, detection electrode 27 and detection frame 23 utilize variable-area capacitance, with a comb-teeth gap of 2 microns.

[0043] like Figure 1 As shown, according to one embodiment of the present invention, a plurality of motion direction conversion structures 1 are regularly arranged. In this embodiment, there are four motion direction conversion structures 1, two of which are connected to a set of Coriolis masses 22 and detection frames 23 in a group, and are mirror-symmetrical.

[0044] Combine Figure 1 and Figure 2 As shown, according to one embodiment of the present invention, the driving frame 21 and the detection frame 22 are both flat structures and are located in the plane; in this embodiment, multiple motion direction conversion structures 1 connect the Coriolis mass 22 and the detection frame 23. A partial enlarged view of the motion direction conversion structure 1 is shown in FIG. Figure 2 As shown, the connection positions of the diamond-shaped bracket 12 and the Coriolis mass beam are different for the upper and lower structures. Such a structural design is also to give full play to the conversion capability of the motion direction conversion structure to the greatest extent.

[0045] like Figure 3 As shown, there are four first anchor points 3, which are fixedly connected to the stationary teeth of the four driving electrodes; there are eight second anchor points 4, which are fixedly connected to the non-connected driving frame end of the driving spring beam; there are four third anchor points 5, which are fixedly connected to the stationary teeth of the four detection electrodes; there are two fourth anchor points 6, which are fixedly connected to the middle part of the driving coupling beam; the rest of the structure is all suspended in the air and is a movable structure

[0046] To further illustrate the present invention, the working modes of the present application scheme are further described with reference to the accompanying drawings.

[0047] 1. Drive mode:

[0048] The comb structure of the driving structure generates a horizontal static electric force to drive the frame 21 to reciprocate in the horizontal direction (i.e., the plane direction of the in-plane sensitive axis micro-mechanical gyroscope). At this time, the mass frame in the gyroscope of the present invention moves back and forth in the horizontal direction, as shown in FIG. Figure 4 shown

[0049] 2. Detection mode:

[0050] When there is an angular velocity input in the direction of the in-plane sensitive axis of the in-plane sensitive axis micromechanical gyroscope, vertical in-plane movement will be generated on the Coriolis mass block 22, and the Coriolis mass block 22 will move up and down out of the plane, driving the diamond-shaped frame structure 12 to generate in-plane movement through the connection of the Coriolis mass beam 11, and its movement direction is on the same axis as the movement direction of the drive frame.

[0051] In this embodiment, in order to detect the sensitive mode motion, Figure 4 It can be seen that in the driving mode of the in-plane sensitive axis micromechanical gyroscope of the present invention, the horizontal movement of the driving frame 21 can only carry out the horizontal movement of the Coriolis mass 22. Only when the Coriolis force acts will the Coriolis mass produce out-of-plane movement, thus achieving modal decoupling.

[0052] Through the above-described configuration, the in-plane sensitive axis micromechanical gyroscope of the present invention, based on the in-plane comb electrostatic drive and in-plane parallel plate capacitance detection principle, features high detection capacitance gain and a high signal-to-noise ratio. Furthermore, the use of four symmetrical large-area sensitive masses (four Coriolis masses 22 and four detection frames 23) enables differential detection, eliminating identical external interference, further ensuring sensitivity and anti-interference capabilities.

[0053] The above content is only an example of a specific solution of the present invention. The present invention proposes a motion direction conversion structure that can convert the in-plane gyroscope detection motion from the up-and-down motion outside the plane to the translational motion inside the plane. In this way, not only can the getter be arranged on the cover plate to increase the quality factor, but also a greater detection electrical signal gain can be obtained. This signal conversion method should be understood as a general method in this field.

[0054] The above description is merely one embodiment of the present invention and is not intended to limit the present invention. Various modifications and variations are possible for other motion-direction-converting structures, such as in-plane sensitive-axis micromechanical gyroscopes that convert out-of-plane motion to in-plane motion. Any modifications, equivalent substitutions, or improvements within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. An in-plane sensitive axis micromechanical gyroscope based on a motion direction conversion structure, characterized in that: The gyroscope comprises: a motion direction conversion structure (1), and other coupling module units (2) connected to the motion direction conversion structure. The motion direction conversion structure (1) comprises: a connecting Coriolis mass rod (11), two triangular beams (12), The other coupling module units include: a driving frame (21), a Coriolis mass (22), a detection frame (23), a driving spring beam (24), a detection spring beam (25), a driving electrode (26), a detection electrode (27), a decoupling beam (28), a first connecting beam (291), a second connecting beam (292), and a sensitive frame coupling beam (30); The gyroscope is bilaterally symmetrical; a first connecting beam (291) is provided on each of the left and right edges of the gyroscope, and the middle portion of the first connecting beam is fixedly connected to the gyroscope substrate; The connection relationship on the left side of the gyroscope is as follows: the triangular beam is a beam composed of two sides of a triangle, and the two triangular beams are arranged horizontally symmetrically with the open ends facing inward; two Coriolis mass rods are placed vertically and parallel, and are disconnected in the middle to form an upper beam and a lower beam; the two triangular beams are respectively located on the left and right sides of the two Coriolis mass rods, the upper ends of the two triangular beams are respectively connected to the two lower beams connected to the Coriolis mass rods, and the lower ends of the two triangular beams are respectively connected to the two upper beams connected to the Coriolis mass rods; the other sides of the two upper beams connected to the Coriolis mass rods are connected to the upper left Coriolis mass, and the other sides of the two lower beams connected to the Coriolis mass rods are connected to the lower left Coriolis mass; an upper left drive frame is provided above the upper left Coriolis mass, and a lower left drive frame is provided below the lower left Coriolis mass, and the left and right sides of each Coriolis mass are connected to the left and right sides of the drive frame via a decoupling beam; each drive frame has a rectangular opening on its left and right sides, and a drive spring beam is provided in each rectangular opening; one side of the drive spring beam is fixed to the substrate and the other side is connected to the drive frame; each triangular beam is connected to a detection frame at its vertex; and each detection frame has a detection electrode. The detection frames on the outer sides of the left and right planes are connected to the middle parts of the first connecting beams on the left and right sides respectively through the detection spring beams; the two detection frames on the inner sides of the left and right planes are connected through the sensitive frame coupling beam; the upper and lower sides of the first connecting beam are also connected to the two driving frames on that side respectively; A driving electrode is provided at each corner of the substrate. Comb teeth are provided on the outside of each driving frame to form a comb pair with the driving electrode. The driving electrode generates horizontal static electricity through the comb pair to make the driving frame move. The right side of the upper left driving frame and the left side of the upper right driving frame are connected via two second connecting beams (292); the right side of the lower left driving frame and the left side of the lower right driving frame are connected via two second connecting beams.

2. The in-plane sensitive axis micromechanical gyroscope according to claim 1, characterized in that: The stiffness of the connected Coriolis mass rod is adjusted by adjusting at least one parameter of the cross-sectional shape, length and setting position of the connected Coriolis mass rod (11).

3. The in-plane sensitive axis micromechanical gyroscope according to claim 1, characterized in that: The driving frame (21), the Coriolis mass (22), and the detection frame (23) are all flat structures, and are in the same plane as the connecting Coriolis mass rod (11), and in an orthogonal plane with the triangular beam (12).

4. The in-plane sensitive axis micromechanical gyroscope according to claim 3, characterized in that: The driving frame (21) is used to drive the Coriolis mass (22) to reciprocate in a direction perpendicular to the plane where the gyroscope is located when detecting the mode; The driving frame (21) is used to drive the Coriolis mass (22) to reciprocate in a gyroscopic plane in a direction perpendicular to a rod connecting the Coriolis mass in a driving mode.

5. The in-plane sensitive axis micromechanical gyroscope according to claim 4, characterized in that: The first connecting beam (291) is a lever beam.

6. The in-plane sensitive axis micromechanical gyroscope according to claim 4, characterized in that: The second connecting beam (292) is an elastic beam, used to connect adjacent driving frames (21).

7. The in-plane sensitive axis micromechanical gyroscope according to claim 4, characterized in that: The sensitive frame coupling beam (30) is an elastic beam used to connect two adjacent detection frames (23).

8. The in-plane sensitive axis micromechanical gyroscope according to claim 1, characterized in that: The detection electrodes adopt a comb-tooth structure and are parallel plates with variable areas or variable gaps.

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