Flexible vibrating beam micro gyroscope based on weak coupling

Abstract

The invention discloses a coupled vibration beam micro gyroscope which comprises a base part, two symmetrical cantilever beams extend out from one side of the base part, and the middle parts of the cantilever beams are connected through a weak coupling beam; the tail ends of the two cantilever beams are respectively provided with a mass block with the same size, electrode plates are arranged on the two sides and below the mass blocks, the lower electrode plates are connected with direct-current voltage and alternating-current voltage to serve as the driving direction, and the electrode plates on the left and right sides of the mass blocks are connected with the direct-current voltage to serve as the sensitive direction. The distances between the three electrode plates in the sensitive direction and the mass block are different, but the whole electrode plates are of a symmetrical structure. During working, the coupled vibration beam micro gyroscope can introduce a modal localization effect in three modes, namely weak coupling beam coupling and electrostatic force coupling, and the coupling strength of a system jointly regulated and controlled by the weak coupling beam and the electrostatic force coupling, and the amplitude ratios of the two vibration gyroscopes are obviously different through the energy concentration effect; the angular velocity is detected by using the amplitude ratio, so that the detection sensitivity of the gyro system can be greatly improved.

Description

Technical Field

[0001] The present invention relates to a vibrating micro gyroscope in the field of inertial sensors, and more specifically, to a coupled vibrating beam micro gyroscope. Background Art

[0002] Inertial sensors have a wide range of applications. Among them, the vibrating micro gyroscope, as a core component of inertial sensors, converts the angular rate of each axis into the displacement of the end mass block through the Coriolis force caused by the orthogonal vibration and rotation, thereby causing a change in capacitance. The rotational angular velocity can be calculated through the change in capacitance. Among them, the electrostatic drive and capacitance detection are the most common driving and detection methods. There are currently many technical difficulties in single-axis vibrating micro gyroscopes, including but not limited to problems such as air damping generated by the internal air pressure of the structure, electrostatic pull-in effect, nonlinear influencing factors caused by the vibrating beam structure and electrostatic force, etc. And the existing rotational speed measurement methods are all based on frequency difference or using the linear relationship of the Coriolis force to determine, lacking a measurement method for high-sensitivity rotational angular velocity. There is an urgent need to increase research efforts in the detection method of vibrating micro gyroscopes to reduce the impact of the backward manufacturing level on the development of domestic vibrating micro gyroscopes.

[0003] In recent years, the phenomenon of modal localization has received extensive attention due to its unique energy local concentration effect. When the system is disturbed in the equilibrium state, it will cause a drastic change in amplitude. This characteristic is very suitable for application in the sensing field, especially for developing high-sensitivity sensors. Now there have been application progresses in aspects such as micro mass sensors, acceleration sensors, charge sensors, etc., but there is still a lack of research on applying the phenomenon of modal localization to the field of vibrating micro gyroscopes. Summary of the Invention

[0004] In view of the deficiencies in the prior art, the present invention proposes a vibrating beam micro gyroscope structure based on weak coupling. In a weakly coupled multi-degree-of-freedom resonant system, the amplitudes of the resonators are the same when not disturbed. When a small perturbation is applied to the structure, it will cause a drastic change in the vibration mode of the system. Therefore, in a misaligned weakly coupled system, the vibration energy will localize and concentrate. The external perturbation is detected based on the amplitude changes of different structures. By introducing the phenomenon of modal localization, this solution realizes the energy transfer between the cantilever beams and innovatively proposes three weak coupling mechanisms: mechanical coupling, electrostatic coupling, and composite coupling. Among them, mechanical coupling has high structural stability, but limited by the processing technology, its coupling strength cannot be changed after the device is formed, and the coupling strength directly affects the sensitivity of the device. Electrostatic coupling effectively solves this problem. By changing the applied voltage, the coupling strength can be dynamically adjusted, thereby improving the sensitivity of the device. The composite coupling method combining the two can more comprehensively regulate the sensitivity of the vibrating micro gyroscope. Different from the traditional vibrating beam gyroscope that uses the Coriolis force or frequency difference to detect the angular velocity, the present invention measures the amplitude ratio of two vibrating units based on the weak coupling mechanism of the multi-degree-of-freedom system to obtain the rotational speed information. This detection method can avoid the interference of factors such as temperature drift and modal mismatch in the traditional Coriolis force or amplitude frequency difference method, and greatly improve the sensitivity of angular velocity measurement.

[0005] The object of the present invention is achieved by the following measures:

[0006] A coupled vibrating beam micro gyroscope includes a base, two symmetric cantilever beams extending from one side of the base, and are connected by a weak coupling beam in the middle; both ends of the two cantilever beams are each provided with a mass block of the same size, and there are electrode plates in the y and z directions of the mass block, where the y direction is the sensitive direction and is connected to a DC voltage, and the z direction is the driving direction and is connected to a DC voltage and an AC voltage.

[0007] As a preferred embodiment, the coupled vibrating beam micro gyroscope includes a base, a first vibrating beam, a second vibrating beam, a weak coupling beam, a first mass block, a second mass block, a first electrode plate, a second electrode plate, a third electrode plate, and a fourth electrode plate. One side of the first vibrating beam is fixed to the base, and the other side is fixed to the first mass block. One side of the second vibrating beam is fixed to the base, and the other side is fixed to the second mass block. The first vibrating beam and the second vibrating beam are symmetrically placed on the base. The first electrode plate is the electrode plate in the driving direction, and the second electrode plate, the third electrode plate, and the fourth electrode plate are the electrode plates in the sensitive direction.

[0008] As a preferred embodiment, one side of the weak coupling beam is fixed to the first vibrating beam, and the other side is fixed to the second vibrating beam. The weak coupling beam is parallel to the base and has a certain distance therebetween. The second electrode plate and the third electrode plate are respectively on both sides of the first mass block in the y direction, and the third electrode plate and the fourth electrode plate are respectively on both sides of the second mass block in the y direction. The distances between the second electrode plate, the third electrode plate, the fourth electrode plate and the first mass block, the second mass block are different. Specifically, the distance between the second electrode plate and the first mass block is equal to the distance between the fourth electrode plate and the second mass block, both being d1, and the distances between the first mass block, the second mass block and the third electrode plate are the same, both being d2, but d1 is not equal to d2; in some aspects, the distance between the second electrode plate and the first mass block is equal to the distance between the third electrode plate and the second mass block, both being d1, and the distance between the third electrode plate and the first mass block is equal to the distance between the fourth electrode plate and the second mass block, both being d2, but d1 is not equal to d2.

[0009] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0010] A coupled vibrating beam micro gyroscope is proposed, which includes three different coupling methods. When working, the first method is that the variable-spacing planar capacitors existing in the y direction will generate different Coriolis forces, and the system has coupling through the weak coupling beam, thereby introducing the weak coupling beam mode localization effect; the second method is that after removing the third electrode plate, the second electrode plate and the fourth electrode plate will generate electrostatic coupling to the first mass block and the second mass block, and at the same time the weak coupling beam will cause weak coupling between the first vibrating beam and the second vibrating beam, which will enable the electrostatic force and the weak coupling beam to jointly control the coupling strength of mode localization; the third method is that after removing the third electrode plate and the weak coupling beam, the second electrode plate and the fourth electrode plate will generate electrostatic coupling to the first mass block and the second mass block, thereby introducing the mode localization phenomenon caused only by the electrostatic force. The mode localization phenomena generated by these three methods will cause obvious changes in the amplitude ratio of the two vibrating gyroscopes. The amplitude ratio is proportional to the micro disturbance (rotation angular velocity), thereby improving the detection sensitivity of the gyroscope. At the same time, the present invention introduces a new method for detecting the angular velocity of a multi-degree-of-freedom vibrating beam micro gyroscope, which has important scientific significance and wide application value. Description of the Drawings

[0011] Figure 1 is a top view structural schematic diagram of the coupled vibrating beam micro gyroscope in the present invention;

[0012] Figure 2 is a forward three-dimensional structural schematic diagram of the coupled vibrating beam micro gyroscope in the present invention;

[0013] Figure 3It is a schematic diagram of the rear three-dimensional structure of the coupled vibrating beam micro gyroscope in the present invention;

[0014] Figure 4 It is a schematic diagram of the lateral three-dimensional structure of the coupled vibrating beam micro gyroscope in the present invention. Specific embodiments

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0016] As Figure 1 and Figure 2 shown, the coupled vibrating beam micro gyroscope provided by the present invention includes a base, two symmetric cantilever beams extending from one side of the base, and are connected by a weak coupling beam in the middle; both ends of the two cantilever beams are each provided with a mass block of the same size, and there are electrode plates in the y and z directions of the mass block, wherein the y direction is the sensitive direction and is connected to a DC voltage, the distance between each mass block and the two surrounding electrode plates is different, the z direction is the driving direction and is connected to a DC voltage and an AC voltage, and the distances between the two mass blocks and the z-direction electrode plates are the same.

[0017] The coupled vibrating beam micro gyroscope includes a base 1, a first vibrating beam 2, a second vibrating beam 3, a first mass block 4, a second mass block 5, a first electrode plate 6, a second electrode plate 7, a third electrode plate 8, a fourth electrode plate 9, and a weak coupling beam 10; the first vibrating beam 2 and the second vibrating beam 3 are both of cantilever beam structure, and the first vibrating beam 2, the second vibrating beam 3 are connected to the weak coupling beam 10; the first electrode plate 6 is the electrode plate in the driving direction, and the second electrode plate 7, the third electrode plate 8, and the fourth electrode plate 9 are the electrode plates in the sensitive direction.

[0018] The base 1 is provided with a first surface 1a and a surface 1b opposite to the first surface. The first surface 1a is fixedly held with one side of the first vibrating beam 2 and the second vibrating beam 3, and the surface 1b is fixedly held with a printed circuit board. The first mass block 4 and the second mass block 5 are provided with a fourth surface 4a and a fifth surface 5a, and the other sides of the first vibrating beam 2 and the second vibrating beam 3 are fixedly held with the fourth surface 4a and the fifth surface 5a. A first electrode plate 6, a second electrode plate 7, and a third electrode plate 8 are respectively provided below and on both sides of the first mass block 4. A first electrode plate 6, a third electrode plate 8, and a fourth electrode plate 9 are respectively provided below and on both sides of the second mass block 5. The first mass block 4 and the second mass block 5 share the first electrode plate 6 and have the same distance from the first electrode plate 6. The first electrode plate 6 is arranged in the z direction, and the second electrode plate 7, the third electrode plate 8, and the fourth electrode plate 9 are arranged in the y direction. The first electrode plate 6 is provided with a sixth surface 6a and is connected to the base 1 with a DC bias and an AC voltage. The second electrode plate 7, the third electrode plate 8, and the fourth electrode plate 9 are respectively provided with a seventh surface 7a, an eighth surface 8a, and a ninth surface 9a. The seventh surface 7a, the eighth surface 8a, and the ninth surface 9a are all connected to the base 1 with a DC bias voltage. The surfaces 6b (not marked) opposite to the sixth surface 6a, the surfaces 7b opposite to the seventh surface 7a, and the surfaces 9b opposite to the ninth surface 9a are all fixedly held with the printed circuit board. The surface 8b (not marked) opposite to the eighth surface 8a is fixedly held with the sixth surface 6a. The above-mentioned fixed connection methods can be achieved by other feasible methods in addition to welding.

[0019] The first vibrating beam 2 is provided with a second surface 2a, and the second vibrating beam 3 is provided with a third surface 3a. Both ends of the weak coupling beam 10 are fixedly held with the second surface 2a and the third surface 3a. The weak coupling beam 10 is parallel to the base 1 and has a certain distance therebetween. The distances between the first mass block 4 and the second electrode plate 7 and the third electrode plate 8 provided on both sides thereof are different. The distances between the second mass block 5 and the third electrode plate 8 and the fourth electrode plate 9 provided on both sides thereof are different. Specifically, in some aspects, the distance between the second electrode plate 7 and the first mass block 4 is equal to the distance between the fourth electrode plate 9 and the second mass block 5, both being d1. The distances between the third electrode plate 8 and the first mass block 4 and the second mass block 5 are the same, both being d2, but d1 is not equal to d2. In some aspects, the distance between the second electrode plate 7 and the first mass block 4 is equal to the distance between the third electrode plate 8 and the second mass block 5, both being d1. The distance between the third electrode plate 8 and the first mass block 4 is equal to the distance between the fourth electrode plate 9 and the second mass block 5, both being d2, but d1 is not equal to d2.

[0020] The coupled vibrating beam micro gyroscope disclosed by the present invention extends the gyroscope to two degrees of freedom. During operation, the Coriolis force will be generated in the y direction of the vibrating beam micro gyroscope. By different coupling methods, the modal localization effect is introduced, thereby increasing the sensitivity of the system. However, the protection scope of the present invention is not limited to this, including multi-degree-of-freedom coupled vibrating beam micro gyroscopes. It can be considered that various coupled vibrating beam micro gyroscopes applying this principle are still within the scope of the claims.

Claims

1. A flexible vibrating beam micro-gyroscope based on weak coupling, characterized in that: The invention comprises a base, two symmetrical cantilever beams extending outward from one side of the base, the middle of the two symmetrical cantilever beams being connected by a weak coupling beam, the other sides of the two symmetrical cantilever beams being fixed by a mass block of the same size; the center of mass of the base is taken as the coordinate origin, an x-axis is taken along the length direction of the cantilever beam, the angular velocity Ω rotating around the x-axis is the detected angular velocity, and two directions perpendicular to the x-axis are respectively a y-axis and a z-axis, which are defined as a sensitive direction and a driving direction; there are electrode plates in the y-direction and the z-direction of the mass block, wherein the electrode plate in the y-direction is connected to the base by a direct current voltage, and the electrode plate in the z-direction is connected to the base by a direct current voltage and an alternating current voltage; the three electrode plates in the y-direction are at different distances from the mass block, and the variable spacing flat plate capacitors of each mass block are symmetrically designed to form a coupled vibration beam micro-gyroscope.

2. The weakly coupled flexible vibrating beam micro-gyroscope according to claim 1, characterized in that: The coupled vibration beam micro-gyroscope comprises a base (1), a first vibration beam (2), a second vibration beam (3), a first mass block (4), a second mass block (5), a first electrode plate (6), a second electrode plate (7), a third electrode plate (8), a fourth electrode plate (9) and a weak coupling beam (10); the first electrode plate (6) is an electrode plate in a driving direction, the second electrode plate (7), the third electrode plate (8) and the fourth electrode plate (9) are electrode plates in a sensitive direction, and the first mass block (4) and the second mass block (5) are driving and detecting elements; the first vibration beam (2) and the second vibration beam (3) are placed symmetrically with respect to the mass point of the base (1), and one side is fixed to the base (1), and the other side is respectively fixed to a fourth surface (4a) provided on the first mass block (4) and a fifth surface (5a) provided on the second mass block (5).

3. The weakly coupled flexible vibrating beam micro-gyroscope according to claim 2, characterized in that: The vibration beam (2) is provided with a second surface (2a), the vibration beam (3) is provided with a third surface (3a), one end of the weak coupling beam (10) is fixed to the second surface (2a), the other end of the weak coupling beam (10) is fixed to the third surface (3a), and the weak coupling beam (10) is parallel to the base (1) and has a certain distance therebetween.

4. The weakly coupled flexible vibrating beam micro-gyroscope according to claim 2, characterized in that: The base (1) is provided with a first surface (1a), the first electrode plate (6) is provided with a sixth surface (6a), the second electrode plate (7) is provided with a seventh surface (7a), the third electrode plate (8) is provided with an eighth surface (8a), and the fourth electrode plate (9) is provided with a ninth surface (9a); a surface (1b) arranged opposite to the first surface (1a), a surface arranged opposite to the sixth surface (6a), a surface (7b) arranged opposite to the seventh surface (7a), and a surface (9b) arranged opposite to the ninth surface (9a) are all fixedly connected to a printed circuit board, and the sixth surface (6a) is fixedly connected to a surface arranged opposite to the eighth surface (8a).

5. The weakly coupled flexible vibrating beam micro-gyroscope according to claim 1, characterized in that: The first electrode plate (6), the second electrode plate (7) and the third electrode plate (8) are all arranged around the first mass block (4); the first electrode plate (6), the third electrode plate (8) and the fourth electrode plate (9) are all arranged around the second mass block (5); the electrode plate (6) is arranged in the z direction; the second electrode plate (7), the third electrode plate (8) and the fourth electrode plate (9) are arranged in the y direction; the first mass block (4) and the second mass block (5) share the first electrode plate (6) and have the same distance from the first electrode plate (6); the first mass block (4) has a different distance from the second electrode plate (7) and the third electrode plate (8) arranged around it; and the second mass block (5) has a different distance from the third electrode plate (8) and the fourth electrode plate (9) arranged around it. The distance between the first mass block (4) and the second electrode plate (7) is equal to the distance between the second mass block (5) and the fourth electrode plate (9), both of which are d1; the distance between the first mass block (4) and the third electrode plate (8) is equal to the distance between the second mass block (5) and the third electrode plate (8), both of which are d2, but d1 is not equal to d2; the distance between the first mass block (4) and the second electrode plate (7) is equal to the distance between the second mass block (5) and the third electrode plate (8), both of which are d1; the distance between the first mass block (4) and the third electrode plate (8) is equal to the distance between the second mass block (5) and the fourth electrode plate (9), both of which are d2, but d1 is not equal to d2.

6. The weakly coupled flexible vibrating beam micro-gyroscope according to claim 2, characterized in that: The vibrating micro-gyroscope composed of the first vibrating beam (2) and the first mass block (4) and the vibrating micro-gyroscope composed of the second vibrating beam (3) and the second mass block (5) are regarded as two independent vibrating beam micro-gyroscopes.

7. The weakly coupled flexible vibrating beam micro-gyroscope according to claim 6, characterized in that: During operation, the method for improving the sensitivity of the coupled vibration beam micro-gyroscope is that after the first electrode plate (6) is applied with an oscillating voltage, the first mass block (4) and the second mass block (5) are caused to move radially. At this time, if the base (1) is rotated, a Coriolis force along the y direction will be generated around the first mass block (4) and the second mass block (5). Due to the different distances between the second electrode plate (7), the third electrode plate (8) and the fourth electrode plate (9) and the first mass block (4) and the second mass block (5), different electrostatic forces will be generated. A small stiffness disturbance is introduced into the system through the weak coupling beam (10), thereby bringing about a modal localization effect caused only by the weak coupling beam. Changing the material properties, geometric parameters and the distance of the weak coupling beam (10) from the base (1) changes the coupling strength of the system.

8. The weakly coupled flexible vibrating beam micro-gyroscope according to claim 6, characterized in that: During operation, the method for improving the sensitivity of the coupled vibration beam micro-gyroscope is to remove the third electrode plate (8); when the base (1) rotates, the first mass block (4) and the second mass block (5) will be subjected to electrostatic coupling from the second electrode plate (7) and the fourth electrode plate (9); in addition, the first vibration beam (2) and the second vibration beam (3) will be subjected to weak coupling generated by the weak coupling beam (10); thus, the electrostatic force coupling and the modal localization effect generated by the weak coupling beam are introduced; and the coupling strength of the system is jointly regulated by these two coupling modes.

9. The weakly coupled flexible vibrating beam micro-gyroscope according to claim 6, characterized in that: During operation, the method for improving the sensitivity of the coupled vibration beam micro-gyroscope is to remove the fourth electrode plate (8) and the weak coupling beam (10). At this time, the system will only be affected by the electrostatic coupling from the second electrode plate (7) and the fourth electrode plate (9), thereby bringing about a modal localization effect caused only by electrostatic force coupling, and the coupling strength of the system is changed by adjusting the value of the input voltage.

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