A capacitive three-axis MEMS gyroscope

Abstract

The present invention discloses a capacitive three-axis MEMS gyroscope structure, comprising an X-axis detection unit and a Z-axis detection unit, modularly cascaded side-by-side in the middle; four sets of drive combs, two of which are located on either side of a unit, along the Y-axis; two sets of drive combs, each located on either side of the Y-axis at the junction of the two units; and a linkage portion, which connects and transmits power to each of the above units and the active parts of each comb. The capacitive three-axis MEMS gyroscope of the present invention simplifies device design through modularization. By sharing drive signals and increasing the modal frequencies of drive and detection, the possibility of direct interference between modal frequencies is reduced, thereby improving shock resistance. The gyroscope significantly improves the detection sensitivity in the Z-axis direction, the anti-interference capability of the gyroscope module, and the overall output accuracy.

Description

Technical Field

[0001] The present invention relates to a micro-electromechanical system (MEMS) gyroscope, in particular to a capacitive three-axis MEMS gyroscope structure, and belongs to the field of semiconductor integrated devices. Background Art

[0002] MEMS (Micro Electro-Mechanical System) refers to a miniaturized device or combination of devices, a comprehensive integrated system that combines electronic with mechanical, optical, or other functions. Its microstructure enables it to achieve intelligent functions in a very small space.

[0003] Capacitive three-axis micromachined gyroscopes, based on micron-scale semiconductor fabrication technology, offer advantages such as high efficiency, precision, heat generation, fast response, and minimal energy loss. Currently, MEMS gyroscopes are widely used in consumer electronics such as smartphones, tablets, and watches, enabling applications such as motion-sensing gaming and fall detection. In recent years, with the increasing demand for intelligent vehicles, inertial navigation systems (INS) based on MEMS gyroscopes have gradually gained traction.

[0004] During vehicle operation, common consumer-grade gyroscopes have poor vibration resistance, making it difficult to guarantee output accuracy (common-mode parasitic noise in a vibration environment interferes with the gyroscope's own detection output). During vibration, the reliability of the gyroscope's own structure may also pose certain problems.

[0005] Currently, most three-axis MEMS gyros are not optimized for the high-precision positioning used in autonomous driving. Because the frequency of directional changes (heading angle) during vehicle movement is higher than that of pitch angle changes, most MEMS three-axis gyros are not optimized for this scenario. This is reflected in the low Z-axis detection sensitivity of existing products, the fact that most Z-axis detection masses are not independent, and the output signals from other axes can interfere with the Z-axis.

[0006] In IC chip design, modularization is often used (such as in AMD's RYZEN processor), but similar designs have not yet been found in MEMS gyroscope devices. Designing different structures for different parameter requirements will consume a lot of designer time and energy. Summary of the Invention

[0007] The purpose of this invention is to propose a capacitive three-axis MEMS gyroscope structure to solve the problem of detection sensitivity of each axis in high-precision positioning scenarios in autonomous driving.

[0008] The technical solution for achieving the above-mentioned purpose of the present invention is a capacitive three-axis MEMS gyroscope structure, including driving comb teeth, driving detection comb teeth and modular cascaded XY axis detection units and Z axis detection units, wherein the XY axis detection unit is provided with four lower electrode plates and a detection mass block suspended above the upper portion thereof distributed around the first center point of the substrate, and the first center point is set as the origin of the intersection of the XY axes, and the four lower electrode plates are divided into a group symmetrically distributed on both sides of the first center point along the X axis and another group symmetrically distributed on both sides of the first center point along the Y axis, the detection mass block is formed into a ring by four wing plates corresponding to the shape and distribution of the lower electrode plates, and is fixed to the substrate by a first anchor point around the first center point and a first group of anchor frames parallel to the Y axis on both sides of the detection mass block, and the detection mass block cooperates with the two groups of lower electrode plates to form a first detection capacitor;

[0009] The Z-axis detection unit is provided with a suspended first swing frame, a second swing frame, and fixed electrode teeth on the substrate within each frame, distributed on both sides of a second center point of the substrate parallel to the Y-axis. The second center point coincides with the extension direction of the X-axis. The two swing frames are integrally connected by a lever support assembly provided therebetween and are fixed to the substrate by a second set of anchor frames parallel to the Y-axis on both sides of the two swing frames. The movable electrodes connected to the two swing frames cooperate with the fixed electrode teeth to form a second detection capacitor.

[0010] Four sets of drive comb teeth, two sets of drive comb teeth are located outside the XY-axis detection unit and are symmetrically distributed on both sides of the first center point along the Y axis, and the other two sets of drive comb teeth are located outside the Z-axis detection unit and are symmetrically distributed on both sides of the second center point parallel to the Y axis. Each set of drive comb teeth includes movable drive electrodes and fixed drive electrodes that cooperate with each other;

[0011] Two groups of drive detection comb teeth are arranged on the outside of the joint of the XY axis detection unit and the Z axis detection unit and are symmetrically distributed on both sides of the second center point parallel to the Y axis. Each group of drive detection comb teeth includes a movable detection electrode and a fixed detection electrode that cooperate with each other; and a linkage part, which is respectively connected to the movable drive electrode, the movable detection electrode, the outer edge of the detection mass block and the outer edge of the two swing frames; wherein the drive comb teeth are used to provide a driving force conforming to the Y axis direction, and drive the movable detection electrode to reciprocate along the Y axis direction through the linkage part, drive the detection mass block to perform a gathered and discrete reciprocating motion relative to the first center point, and drive the two swing frames to perform reciprocating motion relative to the second center point along the direction parallel to the Y axis.

[0012] In the above-mentioned capacitive three-axis MEMS gyroscope structure, further, the four lower electrode plates are all in the shape of isosceles trapezoids and are distributed and assembled into a quasi-square with the first anchor point in the middle.

[0013] In the above-mentioned capacitive three-axis MEMS gyroscope structure, further, the fixed electrode teeth are discretely arranged in an array in each swing frame, and the capacitance value of the second detection capacitor is several times greater than the capacitance value of the first detection capacitor.

[0014] The capacitive three-axis MEMS gyroscope structure further comprises an outer frame and an inner linkage assembly thereof, wherein the outer frame surrounds the XY-axis detection unit and the Z-axis detection unit respectively along a direction parallel to the Y-axis, and is connected to the first set of wing plates, the two swing frames, and the two sets of anchor frames distributed along the Y-axis through the linkage assembly.

[0015] Each group of driving comb teeth and driving detection comb teeth is co-located with the outer frame, and the movable driving electrodes and movable detection electrodes are connected to the side of the outer frame parallel to the X-axis.

[0016] The driving comb teeth drive the first set of wing plates and the two swing frames to perform reciprocating motion along the Y-axis direction through the outer frame and the linkage assembly.

[0017] The above-mentioned capacitive three-axis MEMS gyroscope structure, further, the linkage component includes a veined first linkage beam, a mortise and tenon connection type second linkage beam and a U-shaped third linkage beam, wherein the first linkage beam is connected between the outer frame and the outer edge of the adjacent wing plate, and the two first linkage beams connected to the corresponding side wing plate are symmetrical relative to the Y-axis; the second linkage beam is connected between the outer frame and the outer edge of the adjacent swing frame, and the two second linkage beams connected to the corresponding side swing frame are symmetrical relative to the Y-axis parallel line passing through the second center point; the third linkage beam is connected between the outer frame and the two groups of anchor frames.

[0018] The capacitive three-axis MEMS gyroscope structure further has the outer frame connected to the substrate via a flat frame-type linkage beam and a third anchor point at the outer sides of the driving comb teeth and the driving detection comb teeth away from the two center points.

[0019] The above-mentioned capacitive three-axis MEMS gyroscope structure, further, the detection mass block is provided with a veined fourth linkage beam between adjacent wing plates, and a veined fifth linkage beam is provided between the second group of wing plates distributed along the X-axis and the adjacent anchor frame, and as the first group of wing plates reciprocates, the second group of wing plates are subjected to the transmission force of the fourth linkage beam and reciprocate along the X-axis direction, and the movement amplitude is limited by the buffering of the fifth linkage beam.

[0020] The above-mentioned capacitive three-axis MEMS gyroscope structure further comprises the following: the first anchor point is a point block distributed at the four corners around the first center point, and a square inner frame surrounding all the point blocks is connected from the first anchor point through the sixth linkage beam, and each edge of the inner frame is connected to the edge of the adjacent wing plate through the seventh linkage beam, and the movement amplitude of each wing plate is limited by the sixth linkage beam, the seventh linkage beam and the inner frame buffer.

[0021] The above-mentioned capacitive three-axis MEMS gyroscope structure further comprises a lever support assembly including a second anchor point arranged around a second center point, a diamond-shaped linkage beam, and a third group of anchor frames and lever beams symmetrically distributed on both sides of the second center point along the X-axis, wherein the short axis end point of the diamond-shaped linkage beam is connected to the edge of the adjacent swing frame through an eighth linkage beam of a mortise and tenon connection type, and is connected to the second anchor point through a straight beam parallel to the X-axis; the long axis end point of the diamond-shaped linkage beam is connected to the middle of the third group of anchor frames, and the lever beam on either side is connected to the third group of anchor frames at the midpoint of their respective edges as a support point, and the end of the lever beam is connected to the edge of the adjacent swing frame through a ninth linkage beam of a mortise and tenon connection type.

[0022] The above-mentioned capacitive three-axis MEMS gyroscope structure further has XY-axis detection units and Z-axis detection units arranged side by side on the substrate, the adjacent parts of the first group of anchor frames and the second group of anchor frames are formed into one body, and the adjacent outer frames in the linkage part are connected as a whole through an I-shaped coupling beam.

[0023] The capacitive three-axis MEMS gyroscope of the present invention has outstanding substantial features and the following significant improvements:

[0024] 1. The modular gyroscope design concept only requires changing the core structure of each module or the number of modules to complete the design of multiple single-axis or multi-axis gyroscopes with different parameters. At the same time, the shared driving signal can avoid the influence of forced vibration caused by multiple drives on the output signal; the driving modal frequency and the detection modal frequency are relatively large, which reduces the possibility of direct interference between the modal frequencies and improves the seismic resistance.

[0025] 2. Through the design of each beam in the linkage structure, the function of the capacitive three-axis MEMS gyroscope is realized, and the sensitivity in the Z-axis direction is set much higher than the sensitivity in the XY-axis direction. In this way, the capacitance detection capability in the Z-axis direction (i.e., the direction angle) is enhanced while ensuring the detection accuracy in the XY-axis direction.

[0026] 3. A coupling beam connection structure is used between different modules. The coupling beam will not affect the function of the gyroscope itself, but can reduce the stress between the various gyroscope modules, thereby increasing the output accuracy of the gyroscope module as a whole and reducing interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the front view structure of a preferred embodiment of the three-axis MEMS gyroscope of the present invention in the XY plane.

[0028] Figure 2 yes Figure 1 Detailed structural diagram of the XY-axis detection unit in the three-axis MEMS gyroscope shown.

[0029] Figure 3 yes Figure 1 Detailed structural diagram of the Z-axis detection unit in the three-axis MEMS gyroscope shown.

[0030] Figure 4 yes Figure 1 Schematic diagram of the detailed structure of the linkage part of the three-axis MEMS gyroscope shown.

[0031] Figure 5 yes Figure 1 Schematic diagram of the detailed structure of the connection between the detection mass block and the first anchor point in the three-axis MEMS gyroscope. DETAILED DESCRIPTION

[0032] The specific implementation methods of the present invention will be further described below in conjunction with the accompanying drawings to make the technical solutions of the present invention easier to understand and grasp, thereby making a clearer definition of the protection scope of the present invention.

[0033] like Figures 1 to 5 Figure 2 shows the overall structure and detailed details of a preferred embodiment of the capacitive three-axis MEMS gyroscope of the present invention. This gyroscope is suitable for high-precision positioning in autonomous vehicles. The overall structure comprises a substrate 1, drive comb teeth 2, drive detection comb teeth 3, a linkage, and modularly cascaded X-axis and Y-axis detection units 4 and 5. The essential features of each component are described below.

[0034] The substrate 1 serves as a carrier for all other units, comb teeth, and linkage parts, wherein an XY-axis detection unit and a Z-axis detection unit are arranged side by side in the middle, and the first center point of the XY-axis detection unit is defined as the origin, and the plane where the substrate is located is the spatial rectangular coordinate system of the XY plane, then the Z-axis is perpendicular to the substrate. Figure 1 shown.

[0035] The XY-axis detection unit 4 is provided with four lower electrode plates 41 and a detection mass block 42 suspended above the upper portion thereof, distributed around the first center point A of the substrate. The four lower electrode plates are divided into a group symmetrically distributed on both sides of the first center point along the X-axis and another group symmetrically distributed on both sides of the first center point along the Y-axis. The detection mass block 42 is formed by four wing plates 42a to 42d corresponding to the shape and distribution of the lower electrode plates, which are connected as a whole into a ring shape and fixed to the substrate through a first anchor point 61 around the first center point and a first group of anchor frames 64 on both sides of the detection mass block parallel to the Y-axis. The detection mass block 42 cooperates with the two groups of lower electrode plates 41 to form a first detection capacitor for detecting the input angular velocity in the XY-axis direction.

[0036] The Z-axis detection unit 5 is equipped with a suspended first swing frame 51a and a second swing frame 51b, along a second center point B of the substrate, parallel to the Y-axis. These two swing frames, along with fixed electrode teeth 52 on the substrate within each frame, are arranged on either side of the substrate. The second center point B coincides with the X-axis, meaning that the X-axis of the Z-axis detection unit coincides with or is collinear with the X-axis of the XY-axis detection unit. The two swing frames 51a and 51b are integrally connected by a lever support assembly 7 positioned therebetween. They are secured to the substrate by a second set of anchor frames 65, parallel to the Y-axis, surrounding the two swing frames. The movable electrodes (not labeled) attached to the two swing frames 51a and 51b cooperate with the fixed electrode teeth 52 to form a second detection capacitor for detecting input angular velocity in the Z-axis direction. The movable electrodes and fixed motor teeth are located on the same plane, and their spacing varies with the reciprocating motion of the swing frames.

[0037] The above-mentioned drive comb teeth are preferably provided with four groups, wherein two groups of drive comb teeth 2a are provided outside the XY axis detection unit and are symmetrically distributed on both sides of the first center point A along the Y axis, and the other two groups of drive comb teeth 2b are provided outside the Z axis detection unit and are symmetrically distributed on both sides of the second center point B along the Y axis. Each group of drive comb teeth includes a movable drive electrode 22 and a fixed drive electrode 21 that cooperate with each other, such as Figure 4 shown.

[0038] The above-mentioned drive detection comb teeth 3 are preferably provided in two groups, and are respectively provided on the outside of the joint of the XY axis detection unit and the Z axis detection unit and are symmetrically distributed on both sides of the second center point B along the Y axis. Each group of drive detection comb teeth includes a movable detection electrode 32 and a fixed detection electrode 31 that cooperate with each other. Figure 4 shown.

[0039] The linkage part is distributed and connected between the movable parts of each unit and each comb tooth. Specifically, it involves the movable driving electrode and movable detection electrode of each comb tooth, and is connected to the outer edge of the detection mass block in the XY axis detection unit and the outer edge of the two swing frames in the Z axis detection unit. Due to the discrete distribution, the linkage part is not uniformly marked, and each component is described in detail later; its main function is to transmit the power generated by the AC input driving comb teeth to the suspended detection mass block and swing frame, so that the capacitance of the corresponding detection unit and detection item changes. The above-mentioned driving comb teeth are used to provide a driving force that conforms to the Y-axis direction, and the movable detection electrode is driven to reciprocate along the Y-axis direction through the linkage part, and the detection mass block is driven to make a concentrated and discrete reciprocating motion relative to the first center point, and the two swing frames are driven to make reciprocating motion relative to the second center point in a direction parallel to the Y-axis. It should be noted that the above movement mode is the movement mode of each part of the three-axis MEMS gyroscope when there is no input angular velocity in the X / Y / Z directions. This drives the change in the area facing the plates of the detection comb teeth, and detects the movement of the current driving end through the change in the capacitance between the plates.

[0040] To facilitate understanding of the motion changes and detection principles of the three-axis MEMS gyroscope of the present invention after inputting angular velocity in each axis, the following further details the features of each component of the preferred embodiment.

[0041] like Figure 1 and Figure 2 As shown, the four lower electrode plates 41 are all in the shape of isosceles trapezoids and are distributed and assembled into a quasi-square with the first anchor point 61 in the middle and facing each other in the air. Figure 1 and Figure 3 As shown, the fixed electrode teeth 52 are discretely arranged in an array within each swing frame. Furthermore, as can be seen from the diagram, the combined area of ​​the fixed electrode teeth within the two swing frames is relatively large, resulting in a larger change in the area of ​​the electrodes facing each other within the Z-axis detection unit. This means that the capacitance of the second detection capacitor is exponentially greater than that of the first detection capacitor. In the preferred embodiment shown, this ratio is approximately 4 times greater.

[0042] A key design feature and a key point of protection in this application, the linkage mechanism comprises an outer frame 81 and an inner linkage assembly 82. The outer frame 81 surrounds the XY-axis detection unit and the Z-axis detection unit, respectively, parallel to the Y-axis. Specifically, the XY-axis detection unit is illustrated with a pair of outer frames positioned above and below it, connected to a first set of wings and a first set of anchor frames along the Y-axis via linkage assemblies. The Z-axis detection unit, on the other hand, features another pair of outer frames positioned above and below it, connected to two swinging frames and a second set of anchor frames along the Y-axis via linkage assemblies. Furthermore, each set of drive combs and drive detection combs is co-located with the outer frame. Specifically, the fixed plates of each comb are molded onto the substrate surface and fixed thereto, while the movable plates (including the movable drive electrode and the movable detection electrode) are connected to the sides of the outer frame parallel to the X-axis, creating a suspended structure relative to the substrate. The reciprocating range of the outer frame, projected onto the substrate, lies between the corresponding fixed plates. Simultaneously, the drive combs, through the outer frame and linkage assembly, drive the first set of wings and two swinging frames to reciprocate along the Y-axis.

[0043] More specifically, the linkage assembly 82 includes a first linkage beam 821 of a veined type, a second linkage beam 822 of a mortise and tenon joint type, and a third linkage beam 823 of a U shape. Figure 2As shown, the first linkage beam 821 is connected between the outer frame 81 and the outer edge of the adjacent wing plate 42b (similar to the wing plate 42d side not shown in the figure). The overall appearance is similar to a corrugated spring viewed from the side, and can elastically transmit push-pull power in one direction. Moreover, the two first linkage beams 821 connected to the corresponding wing plate on one side are symmetrical with respect to the Y axis. When the angular velocity in the X-axis direction is input, the wing plate is displaced in the direction perpendicular to the screen. The first linkage beam 821 can reduce the impact of the wing plate on the outer frame 81 when it is displaced in the Z-axis direction, that is, the outer frame 81 will not be lifted up and displaced in the Z direction. Once the outer frame 81 undergoes this displacement, the capacitance output of the drive detection end will be seriously deviated. At the same time, the first linkage beam 821 has sufficient stiffness in the Y-axis direction to ensure that the movement of the outer frame 81 in the Y-axis direction can be transmitted to one side of the wing plate without being absorbed by the first linkage beam, thereby ensuring the stability of the wing plate when it reciprocates along the Y-axis direction. As shown Figure 3 As shown, the second linkage beam 822 is connected between the outer frame 81 and the outer edge of the adjacent swing frame 51a (the swing frame 51b side is omitted in the figure) and is similar. In view of the inductive motion direction of the swing part during Z-axis angular velocity detection, the overall appearance of the second linkage beam here is similar to a mortise and tenon structure combined into one. In the direction of the Y-axis, the outer frame transmits relatively rigid power to the swing frame, and in the direction of the X-axis, it faces the swing frame to achieve motion buffering. Moreover, the two second linkage beams 822 connected to the swing frame on the corresponding side are symmetrical with respect to the Y-axis parallel line C passing through the second center point, and are also used to ensure the stability of the reciprocating motion of the swing frame along the Y-axis. And from Figure 2 and Figure 3 As shown, the third linkage beam 823 is connected between the outer frame and the two groups of anchor frames to buffer the movement of each outer frame.

[0044] In addition to the above two main parts, the linkage part also includes other discrete functional beam components. Figure 4 As shown, the outer frame 81 is connected to the substrate through a flat frame-type linkage beam 83 and a third anchor point 83 on the outside of the driving comb teeth and the driving detection comb teeth away from the two center points, that is, it serves as the outermost suspension support of the outer frame in the Y-axis direction and has an elastic support parallel to the substrate 1.

[0045] like Figure 1 and Figure 2As shown, the proof mass 42 is equipped with a veined fourth linkage beam 84 between adjacent wing plates, while a veined fifth linkage beam 85 is provided between the second set of wing plates 42a and 42c, distributed along the X-axis, and the adjacent anchor frames. As the first set of wing plates 42b and 42d are driven back and forth by the outer frame, the second set of wing plates, driven by the transmission force and traction of the fourth linkage beam 84, will also reciprocate along the X-axis. The general range of motion of the second set of wing plates is buffered by the fifth linkage beam and limited by the anchor frame. Consequently, driven by the outer frame, the proof mass 42 will perform a concentrated and discrete reciprocating motion relative to the first center point A.

[0046] like Figure 2 and Figure 5 As shown, the first anchor point 61 is a block of points distributed around the four corners of the first center point. A square inner frame 81' surrounding all of the points is connected from the first anchor point via a sixth linkage beam 86. Each edge of this inner frame 81' is connected to the edges of adjacent wing panels via a seventh linkage beam 87. Therefore, the range of motion of each wing panel, viewed toward the origin, is limited by the sixth linkage beam 86, the seventh linkage beam 87, and the buffering of the inner frame 81'. Furthermore, as shown, the seventh linkage beam 87 is formed by several long, rectangular frames connected by several short transition beams. Therefore, for any wing panel, the buffering force toward the origin is significantly less than the buffering force toward the sides of the origin.

[0047] In addition to the above linkage parts, the above-mentioned lever support assembly can also be regarded as a miniature linkage structure, but it only acts in the Z-axis detection unit. It includes a second anchor point 62 arranged around the second center point B, a diamond linkage beam 71 and a third group of anchor frames 72 and lever beams 73 symmetrically distributed on both sides of the second center point along the X-axis. The diamond linkage beam 71 is a flat diamond formed by four linear beams of equal length connected end to end. The minor axis endpoint 711 of the diamond-shaped linkage beam connects to the edge of the adjacent swing frame via an eighth linkage beam 88 (similar in shape to the aforementioned second linkage beam 822) with a mortise and tenon joint, and connects to the second anchor point 62 via a straight beam 810 parallel to the X-axis. Simultaneously, the major axis endpoint 712 of the diamond-shaped linkage beam connects to the middle of the third set of anchor frames 72. The lever beams 73 on either side connect to the third set of anchor frames 72 at the midpoint of their respective edges as support points, and the ends of the lever beams 73 connect to the edge of the adjacent swing frame via a ninth linkage beam 89 with a mortise and tenon joint. Consequently, the lever beams swinging relative to the third set of anchor frames drive the swing frame to a slight back-and-forth oscillation along the X-axis.

[0048] like Figure 1 In the preferred embodiment shown, modular XY-axis detection units and Z-axis detection units are arranged side by side on the substrate, and the first group of anchor frames and the second group of anchor frames corresponding to the two detection units are respectively formed into one piece; and the adjacent outer frames in the linkage part are connected as a whole through the I-shaped coupling beam 9.

[0049] The capacitive three-axis MEMS gyroscope of the present invention has a deformable structure driven by the linkage transmission traction. When the gyroscope senses the change in the vehicle's operating state and rotates around any axis, the detection mass block or the swing frame can produce a deformation and distortion effect, thereby achieving the desired measurement accuracy and sensitivity requirements. The specific working principle and motion state are as follows: the drive comb is used to provide a drive wheel along the Y-axis direction. When driven by the outside world, the outer frame 81, the movable drive electrode 22, the movable detection electrode 32, a set of wing plates 42b, 42d, and the two swing frames 51a, 51b will reciprocate along the Y-axis direction, while the other set of wing plates 42a, 42c will reciprocate along the X-axis direction. In the absence of input angular velocity in any axis, for the driving motion of the XY-axis detection unit, the first linkage beam 821 and the seventh linkage beam 87 transmit driving force only in directions orthogonal to the XY axes. The fourth linkage beam 84 is used to transmit the detection mass between the wings in a plane parallel to the substrate, and the fifth linkage beam 85 is used to buffer and limit the reciprocating motion of another set of wings in the X-axis. Therefore, the detection mass in this unit only performs concentrated and discrete reciprocating motion in a plane parallel to the substrate. For the driving motion of the Z-axis detection unit, the second linkage beam 822, the eighth linkage beam 88, and the diamond-shaped linkage beam 7 only transmit driving force or unload force in the direction of the Y axis, while the ninth linkage beam 89 and the third linkage beam 823 are primarily used for limiting the X-axis and buffering the Y-axis. Therefore, the swing frame in this unit only reciprocates along the Y-axis in a plane parallel to the substrate.

[0050] When there is an angular velocity input in the X-axis or Y-axis direction, the Coriolis force causes the wing plates (also known as detection masses in the industry) in the corresponding axial direction to move in the Z-axis direction. For example, with an angular velocity input in the X-axis direction and the Y-axis direction remaining normal, under the action of the Coriolis force, the outer edges of the wing plates 42a and 42c will be limited by the fifth linkage beam and remain coplanar with the anchor frame 64. Driven by the seventh linkage beam 87, the inner frame 81' will maintain the stability of the Y-axis while the X-axis will swing in the Z-axis direction. This means that the inner edges of the wing plates 42a and 42c will experience a noticeable undulating motion relative to the outer edges. As the plate spacing and capacitance change, the angular velocity in the X-axis direction can be detected. The detection of angular velocity input in the Y-axis direction is similar, so further details are omitted.

[0051] When there is an angular velocity input in the Z direction, due to the action of the Coriolis force, under the transmission action of the lever beam 73 and the ninth linkage beam 89, the swing frame will swing back and forth in the X-axis direction. This will also drive the corresponding plate spacing and capacitance to change, thereby detecting the angular velocity in the Z-axis direction. As can be seen from the diagram of the preferred embodiment, the capacitance in the Z-axis direction is designed to be approximately four times the capacitance in the X / Y-axis directions. When detecting movement, the Z-axis quality detection block only moves in the XY plane, which will have a larger capacitor plate area space and a larger capacitance change. This can achieve high sensitivity in Z-axis detection, which is more in line with the needs of high-precision vehicle positioning.

[0052] As can be seen from the diagrams of the above embodiments, the two modular detection units on the left and right can be split and work independently, or they can be spliced ​​together to form an integrated gyro system. As the application expands, more modular detection units can also be spliced ​​together to achieve one design and multiple usage modes to meet various parameter requirements. As for the connection structure of the detection units, the adjacent parts of the first group of anchor frames and the second group of anchor frames are formed into one piece, and the adjacent outer frames in the linkage part are connected as a whole through the I-shaped coupling beam 9. This beam will not affect the movement of the two detection units in the Y-axis direction (the corresponding direction has high rigidity); however, if there is left and right movement caused by stress, the beam can absorb this part of the energy through slight deformation, thereby reducing the impact of thermal stress between the detection units.

[0053] From the above introduction to the structure, functional principles, and detailed description of the embodiments of the capacitive three-axis MEMS gyroscope of the present invention, it can be seen that when applied to vehicle autonomous driving positioning, it has outstanding substantive features and the following significant advancements:

[0054] 1. The modular gyroscope design concept only requires changing the core structure of each module or the number of modules to complete the design of multiple single-axis or multi-axis gyroscopes with different parameters. At the same time, the shared driving signal can avoid the influence of forced vibration caused by multiple drives on the output signal; the driving modal frequency and the detection modal frequency are relatively large, which reduces the possibility of direct interference between the modal frequencies and improves the seismic resistance.

[0055] 2. Through the design of each beam in the linkage structure, the function of the capacitive three-axis MEMS gyroscope is realized, and the sensitivity in the Z-axis direction is set much higher than the sensitivity in the XY-axis direction. In this way, the capacitance detection capability in the Z-axis direction (i.e., the direction angle) is enhanced while ensuring the detection accuracy in the XY-axis direction.

[0056] 3. A coupling beam connection structure is used between different modules. The coupling beam will not affect the function of the gyroscope itself, but can reduce the stress between the various gyroscope modules, thereby increasing the output accuracy of the gyroscope module as a whole and reducing interference.

[0057] In addition to the above embodiments, the present invention may also have other implementation methods. Any technical solutions formed by equivalent replacement or equivalent transformation fall within the scope of protection required by the present invention.

Claims

1. A capacitive three-axis MEMS gyroscope structure, characterized by: It includes driving comb teeth, driving detection comb teeth and modular cascade XY axis detection unit and Z axis detection unit, wherein The XY axis detection unit is provided with four lower electrode plates and a detection mass block suspended above the upper portion thereof, and the first center point is set as the origin of the intersection of the XY axes. The four lower electrode plates are divided into a group symmetrically distributed on both sides of the first center point along the X axis and another group symmetrically distributed on both sides of the first center point along the Y axis. The detection mass block is connected into a ring shape by four wing plates corresponding to the shape and distribution of the lower electrode plates, and is fixed to the substrate by a first anchor point around the first center point and a first group of anchor frames parallel to the Y axis on both sides of the detection mass block. The detection mass block cooperates with the two groups of lower electrode plates to form a first detection capacitor. The Z-axis detection unit is provided with a suspended first swing frame, a second swing frame, and fixed electrode teeth on the substrate within each frame, distributed on both sides of a second center point of the substrate parallel to the Y-axis. The second center point coincides with the extension direction of the X-axis. The two swing frames are integrally connected by a lever support assembly provided therebetween and are fixed to the substrate by a second set of anchor frames parallel to the Y-axis on both sides of the two swing frames. The movable electrodes connected to the two swing frames cooperate with the fixed electrode teeth to form a second detection capacitor. Four sets of drive comb teeth, two sets of drive comb teeth are located outside the XY-axis detection unit and are symmetrically distributed on both sides of the first center point along the Y axis, and the other two sets of drive comb teeth are located outside the Z-axis detection unit and are symmetrically distributed on both sides of the second center point parallel to the Y axis. Each set of drive comb teeth includes movable drive electrodes and fixed drive electrodes that cooperate with each other; Two sets of drive detection comb teeth are located outside the junction of the XY-axis detection unit and the Z-axis detection unit and are symmetrically distributed on both sides of the second center point parallel to the Y-axis. Each set of drive detection comb teeth includes a movable detection electrode and a fixed detection electrode that cooperate with each other. and a linkage portion, which is respectively connected to the movable driving electrode, the movable detection electrode, the outer edge of the detection mass block and the outer edge of the two swing frames; wherein the driving comb teeth are used to provide a driving force in the Y-axis direction, and the movable detection electrode is driven to perform reciprocating motion along the Y-axis direction through the linkage portion, the detection mass block is driven to perform a gathered and discrete reciprocating motion relative to the first center point, and the two swing frames are driven to perform reciprocating motion relative to the second center point in a direction parallel to the Y-axis.

2. The capacitive three-axis MEMS gyroscope structure according to claim 1, characterized in that: The four lower electrode plates are all in the shape of isosceles trapezoids and are distributed and assembled into a quasi-square with the first anchor point in the middle.

3. The capacitive three-axis MEMS gyroscope structure according to claim 1, characterized in that: The fixed electrode teeth are discretely arranged in an array in each swing frame, and the capacitance value of the second detection capacitor is several times greater than the capacitance value of the first detection capacitor.

4. The capacitive three-axis MEMS gyroscope structure according to claim 1, characterized in that: The linkage part includes an outer frame and a linkage component inside thereof. The outer frame surrounds the XY-axis detection unit and the Z-axis detection unit respectively along the direction parallel to the Y-axis, and is connected to the first set of wing plates, two swing frames and two sets of anchor frames distributed along the Y-axis through the linkage component. Each group of driving comb teeth and driving detection comb teeth is co-located with the outer frame, and the movable driving electrodes and movable detection electrodes are connected to the side of the outer frame parallel to the X-axis. The driving comb teeth drive the first set of wing plates and the two swing frames to perform reciprocating motion along the Y-axis direction through the outer frame and the linkage assembly.

5. The capacitive three-axis MEMS gyroscope structure according to claim 4, characterized in that: The linkage assembly includes a veined first linkage beam, a mortise and tenon connection type second linkage beam and a U-shaped third linkage beam, wherein the first linkage beam is connected between the outer frame and the outer edge of the adjacent wing plate, and the two first linkage beams connected to the wing plate on the corresponding side are symmetrical relative to the Y axis; the second linkage beam is connected between the outer frame and the outer edge of the adjacent swing frame, and the two second linkage beams connected to the swing frame on the corresponding side are symmetrical relative to the Y axis parallel line passing through the second center point; the third linkage beam is connected between the outer frame and the two groups of anchor frames.

6. The capacitive three-axis MEMS gyroscope structure according to claim 4, characterized in that: The outer frame is connected to the substrate through a flat frame-type linkage beam and a third anchor point at the outer sides of the driving comb teeth and the driving detection comb teeth away from the two center points.

7. The capacitive three-axis MEMS gyroscope structure according to claim 4, characterized in that: The detection mass block is provided with a veined fourth linkage beam between adjacent wing plates, and a veined fifth linkage beam is provided between the second group of wing plates distributed along the X-axis and the adjacent anchor frames. As the first group of wing plates reciprocates, the second group of wing plates are subjected to the transmission force of the fourth linkage beam and reciprocate along the X-axis direction, and the movement amplitude is limited by the buffering of the fifth linkage beam.

8. The capacitive three-axis MEMS gyroscope structure according to claim 1, characterized in that: The first anchor point is a point block distributed around the four corners of the first center point, and a square inner frame surrounding all the point blocks is connected from the first anchor point through the sixth linkage beam. The edges of the inner frame are connected to the edges of the adjacent wing panels through the seventh linkage beam. The movement range of each wing panel is limited by the sixth linkage beam, the seventh linkage beam and the inner frame buffer.

9. The capacitive three-axis MEMS gyroscope structure according to claim 1, characterized in that: The lever support assembly includes a second anchor point, a diamond-shaped linkage beam, and a third group of anchor frames and lever beams symmetrically distributed on both sides of the second center point along the X-axis, wherein the short axis end point of the diamond-shaped linkage beam is connected to the edge of the adjacent swing frame through an eighth linkage beam of mortise and tenon connection type, and is connected to the second anchor point through a straight beam parallel to the X-axis; the long axis end point of the diamond-shaped linkage beam is connected to the middle of the third group of anchor frames, and the lever beam on either side is connected to the third group of anchor frames at the midpoint of their respective edges as a support point, and the end of the lever beam is connected to the edge of the adjacent swing frame through a ninth linkage beam of mortise and tenon connection type.

10. The capacitive three-axis MEMS gyroscope structure according to claim 1, characterized in that: In the XY axis detection unit and the Z axis detection unit arranged side by side on the substrate, adjacent parts of the first group of anchor frames and the second group of anchor frames are formed into one body, and adjacent outer frames in the linkage part are connected in one body through an I-shaped coupling beam.

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