Monolithic integrated three-axis low-coupling micromechanical gyroscope

Abstract

The invention relates to the field of micro-electro-mechanical system sensors, in particular to a monolithic integrated three-axis low-coupling micromechanical gyroscope which comprises four sensitive mass blocks, an anti-overload mechanism is arranged between two sensitive mass blocks in different directions, two-way cross coupling driving mechanisms are further arranged between the sensitive mass blocks in different directions, and the two-way cross coupling driving mechanisms are arranged between the sensitive mass blocks in different directions. The number of the components is four; the two driving mechanisms can drive the sensitive mass block to move close to or away from the origin of coordinates along the axis; the four out-of-plane detection mechanisms are used for detecting X-axis and Y-axis axial angular velocity signals; the two out-of-plane detection mechanisms are used for detecting Z-axis axial angular velocity signals; and the four driving reading mechanisms are used for feeding back driving signals. According to the invention, driving in a single direction can be realized, unexpected movement of a detection capacitor pole plate and comb teeth is limited, the accuracy of angular velocity detection is improved, and meanwhile, the external overload resistance is high.

Description

Technical Field

[0001] The present invention belongs to the field of MEMS sensors, and particularly relates to a monolithic integrated three-axis low-coupling microelectromechanical gyroscope. Background Art

[0002] Microelectromechanical System (MEMS) technology is an advanced manufacturing technology that integrates micro-mechanical components, sensors, actuators, and electronic circuits on the same silicon-based chip, with significant advantages of miniaturization, high precision, low power consumption, low cost, and mass production; its core lies in using micro-nano processing technology to combine complex mechanical structures with electronic systems to achieve multi-functional integration. MEMS technology is widely used in fields such as consumer electronics, automotive industry, healthcare, aerospace, industrial automation, and the Internet of Things.

[0003] A micro-mechanical vibrating gyroscope is a vibration-type angular velocity sensor based on MEMS technology, used to measure the angular velocity of an object rotating around a certain axis. Its core principle is the Coriolis force effect; when the object rotates, the internal vibration-sensitive mass will be affected by the Coriolis force and generate a displacement perpendicular to the vibration direction. By detecting this displacement change, the angular velocity can be calculated.

[0004] A micro-mechanical three-axis vibrating gyroscope is a micro-mechanical gyroscope capable of simultaneously detecting angular velocities in three orthogonal axes. The current mainstream design generally adopts a single-chip integration scheme, and its significant feature is the sharing of the driving structure, that is, all sensitive masses are driven to vibrate by a driving mechanism in a single direction; however, this design scheme has certain technical challenges in practical applications: due to multiple detection axes (usually two or three axes) sharing a sensitive mass, the output signal of at least one detection axis (mainly the Z axis generating in-plane motion) will be interfered during the driving process, and this interference effect will ultimately lead to a decrease in the measurement accuracy of the gyroscope.

[0005] Therefore, in order to reduce the coupling interference in a monolithic integrated three-axis micro-mechanical gyroscope, certain methods need to be adopted in the design to solve the above problems. Summary of the Invention

[0006] To solve the above problems, the present invention discloses a monolithic integrated three-axis low-coupling microelectromechanical gyroscope, which adopts a variety of decoupling designs in the structure to reduce the coupling between the driving frame and the sensitive mass, and the coupling between the sensitive mass and the Z-axis axial angular velocity detection. This technical solution can solve the problem of the overall accuracy reduction of the gyroscope caused by multiple axes sharing a sensitive mass in the traditional design.

[0007] To achieve the above object, the technical solution of the present invention is as follows: A monolithic integrated three-axis low-coupling micromachined gyroscope. In this design, four sensitive mass blocks are used, which are symmetrically distributed on the XY axes with the structural center as the origin. An anti-overload groove and anti-overload block (anti-overload mechanism) are provided between two adjacent sensitive mass blocks. Each group of anti-overload mechanisms is symmetrically distributed in space and is located at the 45° angle position of the structure, extending from the sensitive mass block in the Y direction towards the sensitive mass block in the X direction into its interior, with a space left in the middle. A bidirectional cross-coupling driving mechanism is also provided between the sensitive mass blocks in each direction for realizing unidirectional driving. There are four anchor points in the central area, which are connected to the central frame through connecting beams. The central frame is respectively connected to the four sensitive mass blocks through folding beams. The driving mechanisms are respectively located on the outer sides of the two sensitive mass blocks in the Y direction, and the supporting decoupling beams, connecting beams, driving comb teeth, etc. are also connected to the driving mechanisms. The in-plane detection mechanisms are respectively located on the outer sides of the two sensitive mass blocks in the X direction. The in-plane detection mechanisms are also connected to the supporting decoupling beams and connecting beams. In addition, a multi-frame and elastic beam mechanism is provided inside the in-plane detection mechanisms for decoupling the movement of the in-plane detection comb teeth. The out-of-plane detection mechanisms are respectively located at the middle positions of the four sensitive mass blocks and are connected to the out-of-plane detection capacitor plates through four folding beams forming crab leg beams. Capacitor plates are also provided on the substrate to form parallel capacitor plate pairs. A driving and readout mechanism is also provided beside the out-of-plane detection mechanism.

[0008] The central area includes four anchor point structures fixed on the substrate. The four sensitive mass blocks are connected by I-shaped elastic beams. A connecting frame is provided outside the anchor points and is connected to the I-shaped elastic beam through a straight beam inside it. The straight beam intersects the I-shaped elastic beam perpendicularly. The connecting frame is square in shape and is formed by subtracting two squares in space. Four folding beams are provided in the XY directions outside the connecting frame. The folding beams are composed of a square-shaped folding beam and half of a square-shaped folding beam. One end of the folding beam is connected to the central connecting frame, and the other end is connected to the four sensitive mass blocks in the XY directions.

[0009] The initial shape of the sensitive mass block is trapezoidal, and it is connected to other frames through a pair of double-fold beams on its outer side. Specifically, the double-fold beam is composed of four long straight beams and several short straight beams, and extends into the interior of the sensitive mass block as a whole. Two of the short straight beams are connected inside the sensitive mass block, and the other short straight beam is connected to other frames outside.

[0010] The interior of the sensitive mass block also includes a driving and readout mechanism, which is composed of a fixed comb tooth fixed on a fixed anchor point and a movable comb tooth fixed on the sensitive mass block.

[0011] The out-of-plane detection mechanisms are all located inside the sensitive mass blocks, including X- and Y-axis axial angular velocity detection mechanisms. The out-of-plane detection mechanisms inside the two sensitive mass blocks in the X direction are used to detect the magnitude of the Y-axis axial angular velocity, and the out-of-plane detection mechanisms inside the two sensitive mass blocks in the Y direction are used to detect the magnitude of the X-axis axial angular velocity. The out-of-plane detection mechanism is composed of four folded beams and a capacitor plate, wherein one end of the folded beam is connected to the sensitive mass block, and the other end is connected to the capacitor comb teeth. The folded beam is composed of two long straight beams and two short straight beams. The four folded beams are arranged on the outside of the capacitor plate in a similar manner to the central symmetrical rotation to form a crab beam.

[0012] The anti-overload groove and the anti-overload block are located between the sensitive mass blocks in different directions, are symmetrically distributed in space, are located at a 45° angle of the structure, and extend from the sensitive mass block in the Y direction toward the sensitive mass block in the X direction to the inside thereof, leaving a certain space in between.

[0013] The bidirectional cross-coupling driving mechanism is located between the sensitive mass blocks in different directions, symmetrically distributed in space, located at a 45° angle of the structure, and connected to two sensitive mass blocks in different directions at both ends. The bidirectional cross-coupling driving mechanism is composed of three folded beams, including four long straight beams and three short straight beams.

[0014] The driving mechanism is located outside the two sensitive mass blocks in the Y direction, and is composed of fixed anchor points, supporting decoupling beams, a driving frame, movable capacitor comb teeth, fixed capacitor comb teeth and anchor points. The driving frame is rectangular as a whole, and its inner side is connected to the sensitive mass blocks in the Y direction through double folded beams; the four fixed anchor points are located in the X direction of the driving frame, near the four corners of the driving frame; the supporting decoupling beam is composed of three long straight beams and three short straight beams, which extend to the inside of the driving frame as a whole, the middle long straight beam is connected to the fixed anchor point, and the two short straight beams are connected to the inside of the driving frame.

[0015] At the center of the driving frame is a driving comb mechanism, which includes four fixed anchor points. The fixed capacitor combs are connected to the fixed anchor points, and the movable capacitor combs are connected to the driving frame and can move in the X direction with the driving frame.

[0016] The in-plane detection mechanism is located outside the sensitive mass block in the X direction, and refers to the Z-axis axial angular velocity detection mechanism. It consists of a fixed anchor point, an external support decoupling beam, a triple frame, a U-shaped beam, a C-shaped beam, an internal support decoupling beam, a movable capacitor comb, a fixed capacitor comb and an anchor point.

[0017] The relative positions and shapes of the fixed anchor and the external support decoupling beam are similar to those of the driving mechanism. The triple-frame includes an external driving frame, an intermediate decoupling frame, and an internal sensitive frame. The inner side of the external frame is connected to the sensitive mass block in the X direction through a double-fold beam. The external support decoupling beam extends into the interior of the external frame and is connected to it through two short straight beams.

[0018] The intermediate frame is located inside the outer frame. There are two cross-shaped beams connected to the external frame in its Y direction. The cross-shaped beam is composed of a long straight beam and three short straight beams. Two short straight beams are connected to the internal frame, and the other short straight beam in the middle is connected to the external frame.

[0019] The internal frame is located inside the intermediate frame. There are four U-shaped beams connected to the intermediate frame near the four corners in its X direction. The U-shaped beam is composed of two long straight beams and three short straight beams. The two outer short straight beams are respectively connected to the intermediate frame and the internal frame.

[0020] An intermediate fixed anchor and an internal support decoupling beam are also provided inside the internal frame. The intermediate fixed anchor is located at the center of the frame. Two support decoupling beams are respectively connected to it in the X direction. The middle long straight beam of the support decoupling beam is connected to the fixed anchor, and the two outer short straight beams are connected to the internal frame.

[0021] An in-plane detection comb structure is also provided inside the internal frame, which includes four fixed anchors. The fixed capacitor combs are connected to the fixed anchors, and the movable capacitor combs are connected to the internal frame.

[0022] The beneficial effects of the present invention are as follows: Through the bidirectional cross-coupling driving mechanism, it is realized that by applying a capacitive driving force only in the Y direction, the sensitive mass blocks in the Y direction and the X direction can be driven to move synchronously. The anti-overload blocks and anti-overload grooves provided in the middle of the sensitive mass blocks can shorten the collision stroke between the sensitive mass blocks, reduce the collision force between the two sensitive mass blocks, and improve the performance of the three-axis micro-machined gyroscope against external environmental overload impacts. The out-of-plane detection mechanism in the middle of the sensitive mass block can enable the detection capacitor plates to still move up and down parallel to the substrate due to the action of the crab-shaped beam when the sensitive mass block moves in the out-of-plane direction. Both the driving and in-plane detection frames are connected to the support decoupling beam, which can limit the out-of-plane movement of the frame when the sensitive mass block performs out-of-plane detection movement, achieving a decoupling effect. The in-plane detection mechanism is composed of a multi-frame and an internal support decoupling beam, which can enable the internal sensitive frame to move only in the Y direction and limit its movement in the X direction, avoiding the movement of the movable comb teeth connected to the internal sensitive frame during driving, eliminating the interference of driving on the detection of the Z-axis axial angular velocity, and improving the detection accuracy of the Z-axis axial angular velocity. Description of the Drawings

[0023] Figure 1Schematic diagram of the overall structure of the present invention.

[0024] Figure 2 Schematic diagram of the structure included in the upper-side sensitive mass region of the present invention.

[0025] Figure 3 Schematic diagram of the structure included in the central region of the present invention.

[0026] Figure 4 Schematic diagram of the structure included in the inner detection region on the left side of the present invention.

[0027] Figure 5 Schematic diagram of the present invention in the driving state.

[0028] Figure 6 Schematic diagram of the present invention in the state of detecting the axial angular velocity in the first direction.

[0029] Figure 7 Schematic diagram of the present invention in the state of detecting the axial angular velocity in the second direction.

[0030] Figure 8 Schematic diagram of the present invention in the state of detecting the axial angular velocity in the third direction.

[0031] List of drawing reference numerals: 11. First sensitive mass; 12. Second sensitive mass; 13. Third sensitive mass; 14. Fourth sensitive mass; 21. Central anchor point; 211, 212, 213, 214. Central first, second, third, and fourth anchor points; 22. Central I-shaped connecting beam; 23. Central folding beam; 231, 232, 233, 234. Central first, second, third, and fourth folding beams; 24. Central frame; 31. Bidirectional cross-coupling driving mechanism; 311, 312. First and second bidirectional cross-coupling driving mechanisms; 32. Anti-overload mechanism; 321, 322. First and second anti-overload mechanisms; 33. Out-of-plane detection capacitor plate; 331. First out-of-plane detection capacitor plate; 34. Out-of-plane detection folding beam; 341, 342, 343, 344. Upper-side out-of-plane detection folding beams; 35. Driving and reading-out capacitor comb teeth; 351. Upper-side driving and reading-out fixed capacitor comb teeth; 352. Upper-side driving and reading-out movable capacitor comb teeth; 36. Connecting beam; 361, 362. Upper-side first and second connecting beams; 363, 364. Left-side first and second connecting beams; 367. Right-side first connecting beam; 37. Driving and reading-out fixed anchor point; 371, 372. Upper-side first and second driving and reading-out fixed anchor points; 41. Driving mechanism fixed anchor point; 42. Driving fixed anchor point; 43. Driving capacitor comb teeth; 44. Driving support decoupling beam; 45. Driving frame; 51. Outer fixed anchor points of in-plane detection mechanism; 511, 512, 513, 514, the first, second, third, and fourth outer fixed anchor points of in-plane detection mechanism on the left side; 52. Inner fixed anchor points of in-plane detection mechanism; 53. In-plane detection fixed anchor points; 531, 532, 533, 534, the first, second, third, and fourth in-plane detection fixed anchor points on the left side; 54. First frame of in-plane detection mechanism; 55. Second frame of in-plane detection mechanism; 56. Third frame of in-plane detection mechanism; 57. Cross-shaped beam of in-plane detection mechanism; 571, 572, the first and second cross-shaped beams of in-plane detection mechanism on the left side; 58. U-shaped beam of in-plane detection mechanism; 581, 582, 583, 584, the first, second, third, and fourth U-shaped beams of in-plane detection mechanism on the left side; 59. Internal support decoupling beam of in-plane detection mechanism; 591, 592, the first and second internal support decoupling beams of in-plane detection mechanism on the left side; 5A. External support decoupling beam of in-plane detection mechanism; 5A1, 5A2, 5A3, 5A4, the first, second, third, and fourth external support decoupling beams of in-plane detection mechanism on the left side; 5B. In-plane detection capacitive comb teeth; 5B1. Movable capacitive comb teeth of in-plane detection mechanism on the left side; 5B2. Fixed capacitive comb teeth of in-plane detection mechanism on the left side. Detailed implementation manners

[0032] The present invention will be further illustrated below in conjunction with the accompanying drawings and specific implementation manners. It should be understood that the following specific implementation manners are only used to illustrate the present invention and not to limit the scope of the present invention.

[0033] As Figure 1 shown, for a monolithic integrated low-coupling three-axis micromechanical gyroscope according to the present invention, in order to more conveniently describe the specific structure in the working mode of the present invention, a three-dimensional coordinate system can be established with the center of the central I-shaped connecting beam 22 as the origin; the plane where the structure is located is the XY horizontal plane, and the Z-axis is determined perpendicular to the XY horizontal plane and facing outward from the paper; in this embodiment, the in-plane detection mechanism refers to the X- and Y-axis axial angular velocity detection mechanisms. The X-axis axial angular velocity detection mechanism is located in the Y-axis direction, and the Y-axis axial angular velocity detection mechanism is located in the X-axis direction; the Z-axis axial angular velocity detection mechanism, that is, the in-plane detection mechanism, is located in the X-axis direction; the driving mechanism is located in the Y-axis direction.

[0034] As Figure 1As shown in the figure, four sensitive mass blocks 11, 12, 13, and 14 are orthogonally and symmetrically distributed in the X and Y axis directions. Two adjacent sensitive mass blocks in different directions are connected by a bidirectional cross-coupling driving mechanism 31. The bidirectional cross-coupling driving mechanisms are symmetrically distributed in space and are located at the four 45° angular positions of the structure, with both ends connected to two sensitive mass blocks in different directions respectively. The anti-overload mechanism 32 is located between the sensitive mass blocks in different directions, symmetrically distributed in space, and located at the 45° angular position of the structure. The anti-overload mechanism 32 includes an anti-overload groove and an anti-overload block. The anti-overload block is located on the sensitive mass block in the Y direction, and the anti-overload groove is located on the sensitive mass block in the X direction, extending from the sensitive mass block in the Y direction towards the sensitive mass block in the X direction into its interior, with a certain space left in the middle. As Figure 1 and Figure 3 shown, the four sensitive mass blocks are connected to the central frame 24 through the central folding beam 23 towards the origin of coordinates; the central frame 24 is connected to the central anchor 21 through the central I-shaped connecting beam 22.

[0035] As Figure 1 and Figure 2 shown, the driving and reading mechanism consists of a driving and reading fixed anchor 37 and a driving and reading capacitor comb 35. The driving and reading mechanism is located at the positions of the four sensitive mass blocks far from the origin of coordinates and is in the middle of the two connecting beams 36 of the sensitive mass blocks in different directions and the driving mechanism or the in-plane detection mechanism. The connecting beam 36 extends into the interior of the sensitive mass block and is connected to it, and the other end is connected to the driving or in-plane detection frame. An out-of-plane detection mechanism is provided in the area between the driving and reading mechanism and the central folding beam 23, which consists of an out-of-plane detection capacitor plate 33 and an out-of-plane detection folding beam 34.

[0036] As Figure 1 shown, the driving mechanism is located outside the two sensitive mass blocks 11 and 12 in the Y direction and consists of a fixed anchor 41, a support decoupling beam 44, a driving frame 45, a pair of driving capacitor combs 43, and an anchor 42. The inner side of the driving frame 45 is connected to the sensitive mass blocks 11 and 12 in the Y direction through the connecting beam 36; the four fixed anchors 41 are located on the X direction of the driving frame, near the four corners of the driving frame 45; the support decoupling beam 44 extends into the interior of the driving frame 45 and is connected to it, and the other end is connected to the fixed anchor 41. Four driving fixed anchors 42 are provided in one side of the driving frame 45, and the fixed anchors 42 are mirror-symmetric with the Y axis as the symmetry axis; a straight beam is connected between the two fixed anchors 42 in the X direction, and a fixed capacitor comb array is evenly distributed on the straight beam. An active capacitor comb array is evenly distributed in the middle of the fixed capacitor comb array. The active capacitor comb is fixed on the driving frame, and the two arrays are arranged in a finger-inserted manner.

[0037] As Figure 1 and Figure 4As shown in the figure, the in-plane detection mechanism is located outside the two sensitive mass blocks 13 and 14 in the X direction, and is composed of outer fixed anchors 51, inner fixed anchors 52, detection fixed anchors 53, the first frame 54, the second frame 55, the third frame 56, a Chinese character-shaped beam 57, a U-shaped beam 58, an internal support decoupling beam 59, an external support decoupling beam 5A, and detection capacitance comb teeth 5B. The inner side of the first frame 54 is connected to the sensitive mass blocks 13 and 14 in the X direction through a connecting beam 36; the four outer fixed anchors 51 are located in the Y direction of the first frame 54, near the four corners of the first frame 54; the external support decoupling beam 5A extends into the first frame 54 as a whole and is connected to it, and the other end is connected to the outer fixed anchor 51. The first frame 54 is connected to the second frame 55 through a Chinese character-shaped beam 57. In one side of the in-plane detection mechanism, there are two Chinese character-shaped beams 571 and 572, which are symmetrically distributed in the Y direction and are mirror-symmetric with the X axis as the axis of symmetry. The second frame 55 is connected to the third frame 56 through a U-shaped beam 58. In one side of the in-plane detection mechanism, there are four U-shaped beams 581, 582, 583, and 584. The U-shaped beams are symmetrically distributed with the center point of the inner fixed anchor 52 as the origin and are arranged in the X direction of the third frame 56. Inside the third frame 56, there are inner fixed anchors 52 and an internal support decoupling beam 59. In one side of the in-plane detection mechanism, there are two internal support decoupling beams 591 and 592, which are symmetrically distributed in the X direction and are mirror-symmetric with the Y axis as the axis of symmetry; one end of the internal support decoupling beam 59 is connected to the inner fixed anchor 52, and the other end is connected to the third frame 56. Inside the third frame 56, there are also in-plane detection fixed anchors 53 and detection capacitance comb teeth 5B; among them, fixed capacitance comb tooth arrays 5B2 are evenly distributed on the straight beam connected to the fixed anchor 53, and movable capacitance comb tooth arrays 5B1 are evenly distributed in the middle of the fixed capacitance comb tooth arrays 5B2. The movable capacitance comb tooth arrays 5B1 are fixed on the third frame 56, and the two arrays are arranged in an interdigitated manner.

[0038] The driving method of the monolithic integrated low-coupling three-axis micro-machined gyroscope provided in this embodiment is variable overlapping area driving. A voltage is applied to the movable driving comb tooth array and the fixed capacitance comb tooth array. Since there are multiple groups of movable-fixed capacitance comb tooth pairs in the array, the normal electrostatic force is offset due to mutual balance, and the driving force is provided by the tangential electrostatic force. When the parameters of the capacitance comb tooth pair are determined, the magnitude of the driving force is only related to the driving voltage.

[0039] The driving force generated on the driving capacitance comb teeth will cause the driving frame 45 to move along the Y direction. At the same moment, the magnitudes of the driving forces received by the upper and lower driving frames 45 are equal, and the directions are opposite. The driving frame 45 moves closer to or farther away from the coordinate origin along the Y-axis direction at the same time. The driving frame is connected to the sensitive mass blocks 11 and 12, and they also move closer to or farther away from the coordinate origin along with the driving frame at the same time.

[0040] Specifically, as Figure 5 shown, due to the presence of the bidirectional cross-coupling driving mechanism 31 (which can return to its original position after slightly deforming), when the sensitive mass blocks 11 and 12 move closer to the origin of coordinates, the upper bidirectional cross-coupling driving beam 31 connected to the sensitive mass blocks 11 and 12 is subjected to a downward force, and the lower bidirectional cross-coupling driving beam 31 is subjected to an upward force; the bidirectional cross-coupling driving beam can convert the force received at one end in the up and down direction into the force at the other end in the left and right direction. Specifically, the parts of the two left bidirectional cross-coupling driving beams 31 connected to the sensitive mass block 13 will be subjected to a rightward force, which will drive the sensitive mass block 13 to move closer to the origin of coordinates along the X direction; while the parts of the two right bidirectional cross-coupling driving beams 31 connected to the sensitive mass block 14 will be subjected to a leftward force, which will drive the sensitive mass block 14 to move closer to the origin of coordinates along the X direction. In this way, the motion states of the sensitive mass blocks 11, 12, 13, and 14 at the same moment are to move closer to or away from the origin of coordinates along the coordinate axes. The bidirectional cross-coupling driving beam 31 realizes the transfer of the driving motion of the sensitive mass block in the single Y direction to the sensitive mass block in the X direction, and makes the motion states of the four sensitive mass blocks "contract and expand" in space.

[0041] Specifically, when the structure is subjected to an overloading impact load from the external environment, the cross-type design of the anti-overloading mechanism 32 reduces the influence on the movement of the sensitive mass blocks 13 and 14 in the X direction by restricting the movement of the sensitive mass blocks 11 and 12 in the Y direction along the X direction. At the same time, the anti-overloading mechanism 32 reduces the influence on the movement of the sensitive mass blocks 11 and 12 in the Y direction by restricting the movement of the beam sensitive mass blocks 13 and 14 in the X direction along the Y direction. In this way, the collision travel between two adjacent sensitive mass blocks in different directions will be shortened, improving the anti-overloading performance of the monolithic integrated low-coupling three-axis micromachined gyroscope.

[0042] Specifically, when an external X-axis axial angular velocity is input, since the driving frame and the sensitive mass blocks 11 and 12 in the Y direction move along the Y direction, the driving frame and the sensitive mass blocks in the Y direction will be affected by the Coriolis force in the Z direction due to the Coriolis effect. The out-of-plane detection mechanism arranged between the sensitive mass blocks 11 and 12 can utilize the Coriolis effect to detect the magnitude of the input X-axis axial angular velocity. For the driving frame 45, the existence of the Coriolis effect will cause the driving frame 45 and the movable capacitor comb tooth array fixed on it to also move along the Z direction. This coupled movement will cause the parameters of the pairs of driving capacitor combs to change, having a negative impact on the driving movement. The equivalent stiffness of the support decoupling beam 44 in the Y direction is small, while it has a large equivalent stiffness in the Z direction. Such a design can greatly limit the movement of the driving frame 45 in the Z direction without affecting the driving movement, eliminating the negative impact of the coupled movement on the driving movement.

[0043] The out-of-plane detection capacitor plates 33 arranged inside the sensitive mass blocks will move horizontally parallel to the substrate during the driving movement. This coupled movement will have a negative impact on the out-of-plane detection. The area of the substrate at the bottom of the out-of-plane detection capacitor plates 33 is designed to be larger than the area of the out-of-plane detection capacitor plates 33. When the out-of-plane detection capacitor plates 33 move horizontally parallel to the substrate, the overlapping area between the two remains unchanged, thus eliminating the negative impact of the coupled movement on the out-of-plane detection.

[0044] Specifically, the function of the driving and reading mechanism is to feedback the magnitude and amplitude of the driving signal, for real-time feedback and regulation of the parameters of the driving voltage to ensure the stability of the driving movement.

[0045] Specifically, as Figure 6 and Figure 7 shown, the traditional out-of-plane detection capacitor plates are directly designed on the sensitive mass blocks. However, the out-of-plane detection movement of the sensitive mass blocks is not always parallel to the substrate. Specifically, when each part of the sensitive mass block performs the detection movement, due to the uneven distribution of the constraint positions, the displacements between different positions of the sensitive mass block and the substrate are not equal. This will result in uneven spacing between the out-of-plane detection capacitor plates and the substrate, and the capacitance change is not completely linear. The out-of-plane detection folding beam 34 designed in the present invention has a small stiffness in the Z direction. When the out-of-plane detection capacitor plates 33 move along the Z direction, it can ensure that the spacing between each position of the capacitor plates and the substrate is equal, and the capacitance change will maintain a linear change.

[0046] Specifically, as Figure 8As shown, when the out-of-plane detection mechanism is driven to move, since the sensitive mass blocks 13 and 14 move along the X direction, the horizontal connecting beam 36 will drive the first frame 54 of the out-of-plane detection mechanism to move along the X direction; at the same time, since the cross-shaped beam 57 has a very large stiffness in the X direction, it will drive the second frame 55 to also move along the X direction; since the inner support decoupling beam 59 has a very large stiffness in the X direction, and one end of the support decoupling beam 59 is connected to the fixed anchor point 52, this design will greatly limit the movement of the third frame in the X direction. When an external Z-axis axial angular velocity is input, since the second frame 55 moves along the X direction, the second frame 55 will be affected by the Coriolis force in the Y direction due to the Coriolis effect, and the second frame 55 will move along the Y direction; since the U-shaped beam 58 has a very large stiffness in the Y direction and the inner support decoupling beam 59 has a relatively small stiffness in the Y direction, the third frame 56 will also move along the Y direction. This multi-frame design will greatly limit the movement of the third frame 56 in the non-expected direction, that is, the X direction, without affecting the movement of the third frame 56 in the expected direction, that is, the Y direction, and has a good decoupling effect.

[0047] It should be noted that the above content only illustrates the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. For those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements all fall within the protection scope of the claims of the present invention.

Claims

1. A monolithic integrated three-axis low-coupling microelectromechanical gyroscope, characterized in that, It includes four sensitive mass blocks, a central area, an in-plane detection mechanism, an out-of-plane detection mechanism, a drive readout mechanism and a drive mechanism. The four sensitive mass blocks are symmetrically distributed on the XY axis with the center of the structure as the origin. An anti-overload mechanism is provided between two adjacent sensitive mass blocks. A bidirectional cross-coupling driving mechanism is also provided between the sensitive mass blocks in different directions to realize unidirectional drive. The central area has four anchor points, which are connected to the central frame through connecting beams. The central frame is connected to the four sensitive mass blocks through folding beams. The drive mechanisms are respectively located on the outsides of the two sensitive mass blocks in the Y direction, and the support decoupling beams, connecting beams and drive comb teeth are also connected to the drive mechanisms. The in-plane detection mechanisms are respectively located on the two sensitive mass blocks in the X direction. On the outside of the sensitive mass block, the in-plane detection mechanism is also connected to the supporting decoupling beam and the connecting beam. In addition, a multiple frame and elastic beam mechanism is arranged inside the in-plane detection mechanism, which is used to decouple the in-plane detection comb tooth movement; the out-of-plane detection mechanism is respectively located in the middle position of the four sensitive mass blocks, and is connected to the out-of-plane detection capacitor plate through a crab leg beam composed of four folded beams. Capacitor plates are also arranged on the substrate to form a parallel capacitor plate pair. A drive readout mechanism is also provided next to the out-of-plane detection mechanism. The drive readout mechanism consists of a drive readout fixed anchor point and a drive readout capacitor comb tooth. The drive readout mechanism is located at a position of the four sensitive mass blocks far away from the coordinate origin, and is located between the sensitive mass blocks in different directions and the two connecting beams of the drive mechanism or the in-plane detection mechanism.

2. The monolithic integrated three-axis low-coupling micromachined gyroscope according to claim 1, characterized in that The anti-overload mechanism is located between the sensitive mass blocks in different directions, symmetrically distributed in space, located at a 45° angle of the structure, extending from the sensitive mass block in the Y direction toward the sensitive mass block in the X direction, leaving space in between.

3. The monolithic integrated three-axis low-coupling micromechanical gyroscope according to claim 1, characterized in that The out-of-plane detection mechanisms are all located inside the sensitive mass blocks, including X- and Y-axis axial angular velocity detection mechanisms. The out-of-plane detection mechanisms inside the two sensitive mass blocks in the X direction are used to detect the magnitude of the Y-axis axial angular velocity, and the out-of-plane detection mechanisms inside the two sensitive mass blocks in the Y direction are used to detect the magnitude of the X-axis axial angular velocity; the out-of-plane detection mechanisms are composed of four folded beams and a capacitor plate, wherein one end of the folded beam is connected to the sensitive mass block, and the other end is connected to the capacitor comb teeth, the folded beam is composed of two long straight beams and two short straight beams, and the four folded beams are arranged on the outside of the capacitor plate and rotated symmetrically with the center to form a crab beam.

4. The monolithic integrated three-axis low-coupling micromachined gyroscope according to claim 1, wherein The in-plane detection mechanism is located outside the sensitive mass block in the X direction, and refers to the Z-axis axial angular velocity detection mechanism; it consists of a fixed anchor point, an external support decoupling beam, a triple frame, a U-shaped beam, a cross-shaped beam, an internal support decoupling beam, a movable capacitor comb tooth, a fixed capacitor comb tooth and an anchor point.

5. The monolithic integrated three-axis low-coupling micromachined gyroscope according to claim 4, characterized in that, The triple-frame includes an external driving frame, an intermediate decoupling frame, and an internal sensitive frame; the internal sensitive frame is located inside the intermediate decoupling frame, and four U-shaped beams are provided near the four corners in its X direction and are connected to the intermediate frame; the U-shaped beam is composed of two long straight beams and three short straight beams, and the two outer short straight beams are respectively connected to the intermediate decoupling frame and the internal sensitive frame; an intermediate fixed anchor and an internal support decoupling beam are also provided inside the internal frame, the intermediate fixed anchor is located at the center of the frame, and two support decoupling beams are respectively connected to it in the X direction; the middle long straight beam of the support decoupling beam is connected to the fixed anchor, and the two outer short straight beams are connected to the internal sensitive frame; an in-plane detection comb structure is also provided inside the internal sensitive frame, which includes four fixed anchors, fixed capacitor combs are connected to the fixed anchors, and movable capacitor combs are connected to the internal sensitive frame.

6. The monolithic integrated three-axis low-coupling micromachined gyroscope according to claim 1, wherein, The driving mechanism is located outside the two sensitive mass blocks in the Y direction and is composed of a fixed anchor, a support decoupling beam, a driving frame, movable capacitor combs, fixed capacitor combs, and an anchor; the driving frame is rectangular as a whole, and its inner side is connected to the sensitive mass block in the Y direction through a double-folded beam; the four fixed anchors are located in the X direction of the driving frame, near the four corners of the driving frame; the support decoupling beam is composed of three long straight beams and three short straight beams, and extends into the driving frame as a whole, the middle long straight beam is connected to the fixed anchor, and the two short straight beams are connected to the inside of the driving frame.

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