Gyroscope

Abstract

The gyroscope comprises a universal joint support and four main mass blocks which are suspended on the universal joint support and symmetrically distributed around the center of a universal joint, one side, close to the universal joint support, of each main mass block is connected with a first seesaw assembly, and the main mass blocks are attached to the universal joint support through the first seesaw assemblies; the side, away from the universal joint support, of each main mass block is connected with a second seesaw assembly, the main mass blocks are attached to the corresponding fixed mass blocks through the second seesaw assemblies, each first seesaw assembly is connected with driving comb teeth, driving voltage is applied to the driving comb teeth, and the driving comb teeth are connected with the corresponding fixed mass blocks through the second seesaw assemblies. And the first seesaw assembly is driven to drive the main mass block to perform reciprocating vibration around the Z axis in the four-antinode 0-degree direction at the driving frequency. Three-axis angular rate detection can be achieved only through one drive control loop, and the three-axis angular rate detection device is simple in structure, high in precision and low in cost.

Description

Technical Field

[0001] The present invention relates to the technical field of micro-electromechanical devices, and in particular to a gyroscope. Background Art

[0002] With the rapid development of emerging intelligent application fields such as micro-robots, micro-drones, and visual stabilization, the demand for high-precision, small-volume single-chip integrated three-axis MEMS gyro sensors is becoming increasingly urgent. The traditional monolithic three-axis gyro module formed by integrating several single-axis or multi-axis micromechanical gyroscope structures in the system has problems such as being too large in size and too high in cost. Even if multiple single-axis or multi-axis gyroscopes are combined and assembled into a monolithic MEMS gyro micro-electromechanical system, each gyro sensor still needs to have its own drive circuit and detection circuit.

[0003] The single-chip three-axis integrated MEMS gyroscope realizes resonant motion in two orthogonal directions through a driving structure, and realizes angular rate signal detection in three axes through detection mode coupling, with a high degree of integration. The device area of ​​the existing three-axis integrated balanced gyroscope detection structure of TDK-InvenSense and the three-axis integrated heartbeat gyroscope detection structure of ST are both less than 3mm×3mm, but the resonant mode of the gyroscope detection structure presents anisotropic distribution, and the modal distribution of the gyroscope mass, stiffness, and damping coefficient is uneven, which leads to large orthogonal errors in the micro-nano processing process, limiting the further improvement of the gyroscope accuracy. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a gyroscope which can realize three-axis angular rate detection with only one driving control loop and has a simple structure, high precision and low cost.

[0005] The technical solution adopted by the present invention to solve its technical problems is: to provide a gyroscope, characterized in that it includes a universal joint bracket and four main mass blocks suspended on the universal joint bracket and symmetrically distributed around the center of the universal joint, each main mass block is connected to a first seesaw assembly on a side close to the universal joint bracket, and is attached to the universal joint bracket through the first seesaw assembly, each main mass block is connected to a second seesaw assembly on a side away from the universal joint bracket, and is attached to the corresponding fixed mass block through the second seesaw assembly, each of the first seesaw assemblies is connected to a driving comb tooth, a driving voltage is applied to the driving comb tooth, and the first seesaw assembly is driven to drive the main mass block to vibrate reciprocatingly around the Z axis in the four wave-node 0 degree directions at a driving frequency.

[0006] Furthermore, the second seesaw assembly includes a seesaw coupling, and is attached to the main mass block via an axial rod of the seesaw coupling, so that the main mass block can move horizontally and up and down with the axial rod as support.

[0007] Furthermore, first detection comb teeth are symmetrically distributed on both sides of the seesaw coupling, and the first detection comb teeth extend toward the fixed mass block.

[0008] Further, the X-axis and the Y-axis are set to intersect orthogonally at the center of the universal joint in the same plane, and the Z-axis intersects orthogonally with both the X-axis and the Y-axis; the main mass block includes a first main mass block, a second main mass block, a third main mass block and a fourth main mass block, wherein the first main mass block is symmetrical with the third main mass block along the X-axis, and the second main mass block is symmetrical with the fourth main mass block along the Y-axis; the drive comb teeth include a first drive comb tooth, a second drive comb tooth, a third drive comb tooth and a fourth drive comb tooth, wherein the first drive comb tooth is symmetrical with the third drive comb tooth along the Y-axis, the first drive comb tooth is symmetrical with the second drive comb tooth along the X-axis, the second drive comb tooth is symmetrical with the fourth drive comb tooth along the Y-axis, and the third drive comb tooth is symmetrical with the fourth drive comb tooth along the X-axis; the first main mass block is attached to the first drive comb tooth and the third drive comb tooth through the axis rod connected thereto, and the third main mass block is attached to the second drive comb tooth and the fourth drive comb tooth through the axis rod connected thereto.

[0009] Furthermore, the detection signal output by the first detection comb attached to the first main mass block and the third main mass block is used to calculate the angular velocity input along the X-axis; the detection signal output by the first detection comb attached to the second main mass block and the fourth main mass block is used to calculate the angular velocity input along the Y-axis.

[0010] Furthermore, it also includes four second detection comb teeth symmetrically distributed around the center of the universal joint, each of the second detection comb teeth is connected to an angle spring, and the angle springs extend to both sides to connect with two adjacent main mass blocks.

[0011] Furthermore, the second detection comb teeth are used to calculate the angular velocity input along the Z axis.

[0012] Furthermore, the first seesaw assembly includes a first seesaw, which is a three-pronged structure, and its two side forks are respectively connected to the same side forks of two adjacent main mass blocks and two adjacent first seesaws, and its central fork is respectively connected to the universal joint bracket and the driving comb teeth.

[0013] Furthermore, two ends of the seesaw coupling are connected with rotating shafts, and are attached to two ends of the fixed mass block through the rotating shafts.

[0014] Furthermore, the main mass block is a Coriolis mass block.

[0015] Beneficial Effects

[0016] Due to the adoption of the above-mentioned technical scheme, the present invention has the following advantages and positive effects compared with the prior art: the present invention designs four substructures suspended on the universal joint bracket and symmetrically distributed, and adopts a flexible bearing structure to attach the Coriolis mass block and the fixed mass block in the substructure that work in a quasi-four-antenna resonance, so that the three-axis angular rate detection can be achieved by using a single drive mode vibration (only one drive control loop is required for all axes), which significantly reduces the complexity and cost of the device; the present invention sets the Coriolis mass block to precess in the four-antenna 0-degree direction, so that the Coriolis mass block and the coupling structure can perform Z-axis angular rate detection through a quasi-four-antenna 45-degree direction vibration mode, and can effectively decouple the response mode for each axis to reduce the cross-axis sensitivity, while using the 4 symmetrical Coriolis mass blocks fixed in the center and the "seesaw" structure to detect the angular rates of the X-axis and Y-axis, thereby improving the accuracy of detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of an embodiment of the present invention;

[0018] Figure 2 is a driving simulation diagram of an embodiment of the present invention;

[0019] Figure 3 is a simulation diagram of X-axis angular velocity detection according to an embodiment of the present invention;

[0020] Figure 4 It is a simulation diagram of Y-axis angular velocity detection according to an embodiment of the present invention;

[0021] Figure 5 It is a simulation diagram of Z-axis angular velocity detection according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0023] The embodiment of the present invention relates to a novel single-drive three-axis integrated MEMS gyroscope sensitive structure design with a wine glass-like four-antenna working mode. The driving mode and detection mode of the MEMS gyroscope respectively present the working modes in the 0-degree and 45-degree directions under the wine glass-like four-antenna resonance mode. The single-drive three-axis integrated MEMS gyroscope with a wine glass-like working mode includes four symmetrically distributed Coriolis main mass block components, a single-axis driving electrode, and a three-axis detection electrode. The four symmetrically distributed Coriolis main mass block components are suspended on a central universal joint bracket to form a central suspension system, and each Coriolis main mass block component is configured to precess in the four-antenna 0-degree direction. The driving electrode includes a flexible part and a fixed part, the fixed part is symmetrically distributed in the ±90-degree direction, and the flexible part is connected to the Coriolis main mass block component to drive the four Coriolis main mass blocks to precess in the four-antenna 0-degree direction. The detection electrodes include detection electrodes in three axes of X, Y, and Z, each including a flexible portion and a fixed portion, wherein the flexible portion and the fixed portion of the Z axis are configured in a 45-degree direction of four antinodes, and the flexible portion and the fixed portion of the detection electrodes of the X axis and the Y axis are configured in an orthogonal symmetrical distribution. The driving electrode and the central suspension system are configured to make the three-axis gyroscope reciprocate around the Z axis (which is perpendicular to the XY plane) at a driving frequency in a 0-degree direction of four antinodes.

[0024] Details are as attached Figure 1 As shown, the size of the gyroscope is 1.6mm*1.6mm, and its upper mechanical structure is composed of four identical substructures 100, 200, 300, and 400. The four substructures 100, 200, 300, and 400 are symmetrically arranged and connected to each other through four mass blocks 1a, 1b, 1c, and 1d and the central universal joint 2. At the same time, the four substructures 100, 200, 300, and 400 are all connected to the seesaw couplings 3a, 3b, 3c, and 3d. The first coupling 3a is connected to the first fixed mass block 4a through the first torsion bar pair 5a, the second coupling 3b is connected to the second fixed mass block 4b through the second torsion bar pair 5b, the third coupling 3c is connected to the third fixed mass block 4c through the third torsion bar pair 5c, and the fourth coupling 3d is connected to the fourth fixed mass block 4d through the fourth torsion bar pair 5d. The four groups of torsion bar pairs 5a, 5b, 5c, and 5d are all in the XY plane. The central universal joint 2 is composed of 2a, 2b, 2c, and 2d. The four universal joints 2a, 2b, 2c, and 2d are connected to the rigid seesaw structures 6a, 6b, 6c, and 6d respectively.

[0025] The first substructure 100 is composed of a mass block 1a, a central universal joint 2a, a seesaw coupling 3a, a fixed mass block 4a, a first torsion bar pair 5a, a rigid seesaw 6a, a driving comb 7a, and X-axis detection combs 8a, Y-axis detection combs 9a, Z-axis detection combs 10a, and an angular spring 11a. The second substructure 200 is composed of a mass block 1b, a central universal joint 2b, a seesaw coupling 3b, a fixed mass block 4b, a second torsion bar pair 5b, a rigid seesaw 6b, a driving comb 7b, and X-axis detection combs 8b, Y-axis detection combs 9b, Z-axis detection combs 10b, and an angular spring 11b. The third substructure 300 is composed of a mass block 1b, a central universal joint 2c, a seesaw coupling 3c, a fixed mass block 4c, a third torsion bar pair 5c, a rigid seesaw 6c, a driving comb 7c, and X-axis detection combs 8c, Y-axis detection combs 9c, Z-axis detection combs 10c, and an angular spring 11c. The fourth substructure 400 is composed of a mass block 1d, a central universal joint 2d, a seesaw coupling 3d, a fixed mass block 4d, a fourth torsion bar pair 5d, a rigid seesaw 6d, a driving comb 7d, and X-axis detection combs 8d, Y-axis detection combs 9d, Z-axis detection combs 10d, and an angular spring 11d.

[0026] The fixed part of the driving electrode includes driving comb teeth 7a, driving comb teeth 7b, driving comb teeth 7c, and driving comb teeth 7d, and the flexible part includes rigid seesaws 6a, rigid seesaws 6b, rigid seesaws 6c, and rigid seesaws 6d; the fixed part of the X-axis detection electrode includes X-axis detection comb teeth 8a, X-axis detection comb teeth 8b, X-axis detection comb teeth 8c, and X-axis detection comb teeth 8d, and the flexible part includes seesaw couplings 3a and seesaw couplings 3d; the Y-axis detection electrode The fixed part of the electrode includes Y-axis detection comb teeth 9a, Y-axis detection comb teeth 9b, Y-axis detection comb teeth 9c, and Y-axis detection comb teeth 9d, and the flexible part includes seesaw coupling 3b and seesaw coupling 3c; the fixed part of the Z-axis detection electrode includes Z-axis detection comb teeth 10a, Z-axis detection comb teeth 10b, Z-axis detection comb teeth 10c, and Z-axis detection comb teeth 10d, and the flexible part includes angle springs 11a, angle springs 11b, angle springs 11c, and angle springs 11d.

[0027] Apply an AC voltage with a DC bias to the fixed drive comb teeth 7a, 7b, 7c, and 7d to realize the electrostatic drive of the gyroscope. Figure 2 shown.

[0028] This new wine glass-like single-drive three-axis integrated MEMS gyroscope adopts a single-axis electrostatic drive and a working mode of X, Y, and Z three-axis capacitance detection. An AC voltage with a DC bias voltage is applied to the fixed drive comb teeth to generate an alternating electrostatic force. The electrostatic driving force is:

[0029]

[0030] Where n is the number of active comb teeth of the resonator, ε is the dielectric constant, h is the thickness of the structure, d is the comb tooth spacing, and U is a is the DC bias voltage of the driving voltage, U d is the AC voltage, ω d is the angular frequency of the AC voltage.

[0031] Therefore, the entire active structure of the substructures 100, 200, 300, and 400 performs opposite simple harmonic linear vibrations along the driving axis under the action of the electrostatic driving force. When the frequency of the driving AC voltage is consistent with the natural frequency of the gyroscope driving mode, the linear vibration displacement is:

[0032]

[0033] In the formula, F d0 is the electrostatic driving force amplitude, k x is the elastic stiffness in the X direction, Q x is the quality factor of the driving mode. The linear vibration velocity is:

[0034]

[0035] When the gyroscope has an external input angular velocity along the X-axis, according to the right-hand rule, the detection mass is subjected to the Coriolis acceleration in the detection axis direction. At this time, the X-axis direction generates De Coriolis forces upward from the upper side and downward from the lower side. Figure 3 shown.

[0036] When the gyroscope has an external input angular velocity along the Y axis, according to the right-hand rule, the detection mass is subjected to the Coriolis acceleration in the detection axis direction. At this time, the Y axis direction generates De Coriolis forces upward on the left side and downward on the right side. Figure 4 shown.

[0037] When the gyroscope has an external input angular velocity along the Z axis, according to the right-hand rule, the detection mass is subjected to the Coriolis acceleration in the detection axis direction. At this time, the Y axis direction generates a De Coriolis force that contracts in the upper left and lower right, and expands in the lower left and upper right, as shown in Figure 5 shown.

[0038] After the capacitance difference signal is processed by the electronic circuit, an output voltage signal can be obtained. The output voltage signal is the sum of the output voltage signals of the substructures 100, 200, 300, and 400, and the magnitude of the output voltage signal is proportional to the magnitude of the input angular velocity. By comparing the phase relationship between the output voltage signal and the excitation signal through the phase detector, the direction of the input angular velocity can be determined.

Claims

1. A gyroscope, characterized in that: It includes a universal joint bracket and four main mass blocks suspended on the universal joint bracket and symmetrically distributed around the center of the universal joint, each main mass block is connected to a first seesaw assembly on a side close to the universal joint bracket, and is attached to the universal joint bracket through the first seesaw assembly, each main mass block is connected to a second seesaw assembly on a side away from the universal joint bracket, and is attached to a corresponding fixed mass block through the second seesaw assembly, each of the first seesaw assemblies is connected to a driving comb tooth, a driving voltage is applied to the driving comb tooth, and the first seesaw assembly is driven to drive the main mass block to reciprocate around the Z axis in the four wave-node 0 degree directions at a driving frequency.

2. The gyroscope according to claim 1, characterized in that The second seesaw assembly includes a seesaw coupling and is attached to the main mass block via an axial rod of the seesaw coupling, so that the main mass block can move horizontally and up and down with the axial rod as support.

3. The gyroscope according to claim 2, characterized in that: First detection comb teeth are symmetrically distributed on both sides of the seesaw coupling, and the first detection comb teeth extend toward the fixed mass block.

4. The gyroscope according to claim 3, characterized in that: The X-axis and the Y-axis are set to intersect orthogonally at the center of the universal joint in the same plane, and the Z-axis intersects orthogonally with both the X-axis and the Y-axis; the main mass block includes a first main mass block, a second main mass block, a third main mass block and a fourth main mass block, wherein the first main mass block is symmetrical with the third main mass block along the X-axis, and the second main mass block is symmetrical with the fourth main mass block along the Y-axis; the drive comb teeth include a first drive comb tooth, a second drive comb tooth, a third drive comb tooth and a fourth drive comb tooth, wherein the first drive comb tooth is symmetrical with the third drive comb tooth along the Y-axis, the first drive comb tooth is symmetrical with the second drive comb tooth along the X-axis, the second drive comb tooth is symmetrical with the fourth drive comb tooth along the Y-axis, and the third drive comb tooth is symmetrical with the fourth drive comb tooth along the X-axis; the first main mass block is attached to the first drive comb tooth and the third drive comb tooth through the axis rod connected thereto, and the third main mass block is attached to the second drive comb tooth and the fourth drive comb tooth through the axis rod connected thereto.

5. The gyroscope according to claim 4, characterized in that: The detection signal output by the first detection comb attached to the first main mass block and the third main mass block is used to calculate the angular velocity input along the X-axis; the detection signal output by the first detection comb attached to the second main mass block and the fourth main mass block is used to calculate the angular velocity input along the Y-axis.

6. The gyroscope according to claim 2, characterized in that: It also includes four second detection comb teeth symmetrically distributed around the center of the universal joint, each of the second detection comb teeth is connected to an angle spring, and the angle springs extend to both sides to connect with two adjacent main mass blocks.

7. The gyroscope according to claim 6, characterized in that The second detection comb teeth are used to calculate the angular velocity input along the Z axis.

8. The gyroscope according to claim 2, characterized in that: The first seesaw assembly includes a first seesaw, which is a three-pronged structure, and its two side forks are respectively connected to the same side forks of two adjacent main mass blocks and two adjacent first seesaws, and its central fork is respectively connected to the universal joint bracket and the driving comb teeth.

9. The gyroscope according to claim 2, characterized in that: The two ends of the seesaw coupling are connected with rotating shafts, and are attached to the two ends of the fixed mass block through the rotating shafts.

10. The gyroscope according to claim 1, characterized in that The main mass block is a Coriolis mass block.

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