A MEMS gyroscope structure with amplitude amplification effect

Abstract

The utility model discloses a technical scheme provides a kind of structure of elliptical annular structure and comb tooth structure combination to form lever action to carry out displacement amount amplification to sensitive mode, and eliminate parasitic mode between driving mode and sensitive mode, while improving the long-term and short-term zero bias stability of gyroscope;According to the technical scheme of the utility model, using symmetrical large-area sensitive mass, with the advantage of driving mode and detection mode decoupling, also has larger signal output gain;Symmetrical sensitive mass and detection frame are used, differential detection can be realized, the same interference of outside is differentially dropped, further guarantee sensitivity and anti-interference ability;And symmetrical structure can effectively suppress processing error, thereby improve the stability of gyroscope.

Description

Technical Field

[0001] This utility model relates to the field of silicon micromechanical gyroscope technology, specifically to a MEMS gyroscope structure with amplitude amplification function. Background Technology

[0002] A gyroscope is a sensor that measures the rotational motion of a carrier relative to inertial space. It is a core component in motion measurement, inertial navigation, and platform stabilization, and has significant application value in high-end industrial equipment such as aerospace, intelligent robots, automotive electronics, and drones. Currently, gyroscopes are mainly classified into rotor gyroscopes, fiber optic gyroscopes, laser gyroscopes, and microelectromechanical (MEMS) gyroscopes. Among them, capacitive silicon microelectromechanical gyroscopes, as an inertial sensor based on MEMS technology, have been widely used in aerospace, automotive electronics, and consumer electronics due to their advantages such as small size, low cost, high reliability, and mass production capability. However, with the continuous improvement of application requirements, their insufficient sensitivity and poor zero-bias stability have gradually become prominent issues, becoming key factors restricting their further development.

[0003] The sensitivity of a capacitive silicon micromachined gyroscope (CMEMS) refers to the ratio of its output signal to the input angular velocity. Higher sensitivity means a stronger ability to detect minute changes in angular velocity. However, current CMEMS CMEMS gyroscopes have some shortcomings in terms of sensitivity. For example, due to structural design limitations, the sensitivity of the gyroscope is closely related to the matching degree between the driving mode and the detection mode. If the natural frequencies of the two modes do not match, it will lead to a decrease in energy transfer efficiency, thereby reducing sensitivity. Furthermore, in practical applications, it is easily affected by environmental factors such as temperature changes and mechanical vibrations, which can cause a decrease in the gyroscope's sensitivity. Zero-bias stability refers to the stability of the gyroscope's output signal when there is no input angular velocity. Poor zero-bias stability will increase the measurement error of the gyroscope, affecting its accuracy in long-term measurements. The zero-bias stability problem of capacitive silicon micromechanical gyroscopes is mainly due to the fact that the manufacturing process can cause large residual stresses in the structure, which affect the resonant frequency of the gyroscope and thus lead to poor zero-bias stability. In addition, environmental factors such as temperature changes and electromagnetic interference can also affect the zero-bias of the gyroscope, causing it to exhibit different zero-bias characteristics under different environments. Furthermore, due to the structural design and manufacturing precision limitations of the gyroscope, there may be mechanical coupling between the driving mode and the sensing mode, which can lead to fluctuations in the zero-bias.

[0004] Capacitive silicon micromechanical gyroscopes face challenges in practical applications, including insufficient sensitivity and poor zero-bias stability, which limits their use in high-precision measurement. Current technologies often attempt to improve gyroscope performance and address these issues through structural design optimization, process improvements, and the application of signal processing techniques.

[0005] However, there is currently no ideal solution to address the above problems. Among many solutions, structural design optimization is relatively low-cost and effective. Therefore, considering the problems existing in silicon micromechanical gyroscopes, it is of great significance to propose a design improvement that can enhance gyroscope sensitivity through structural design, thereby improving gyroscope accuracy (short-term zero-bias stability) and meeting the growing application demands. Utility Model Content

[0006] This invention addresses the problems of insufficient sensitivity and poor zero-bias stability in existing silicon micromechanical gyroscopes by proposing a MEMS gyroscope structure with amplitude amplification. The technical solution of this invention optimizes the gyroscope structure by combining an elliptical ring structure with a comb-like structure to create a lever effect that amplifies the displacement of the sensitive mode. Furthermore, the driving structure, detection structure, and mass block are independent of each other. The driving structure is restricted by the driving frame lever and can only move along the driving direction; the detection structure is restricted by its supporting structure and can only move along the detection direction; the mass block has two degrees of freedom in the plane, achieving decoupling. The dimensions of the key flexible beam are systematically adjusted rather than the topology is altered, tuning the frequencies of the driving and detection modes to the first three orders of the system, and pushing the frequency of the main parasitic modes to the fourth order or higher. This eliminates the parasitic modes between the driving and sensitive modes, while improving the long-term and short-term zero-bias stability of the gyroscope.

[0007] This utility model is achieved through the following technical means: A MEMS gyroscope structure with amplitude amplification includes a drive frame and at least one set of two mass blocks, a drive structure, and a detection structure. The drive frame consists of x-axis rigid beams 8a and 8b and y-axis rigid beams 9a and 9b connected to the left and right ends of the x-axis rigid beams 8a and 8b, respectively. The x-axis rigid beams 8a and 8b are fixed to the drive frame at anchor points. The y-axis rigid beams 9a and 9b are connected to two mass blocks 7a and 7b, respectively. The driving structure includes detection-drive decoupling beams 24a and 24b and multiple sets of comb tooth structures. Detection-drive decoupling beams 24a and comb tooth structures are connected to the y-axis rigid beam 9a and distributed on both sides of the mass block 7a. Detection-drive decoupling beams 24b and comb tooth structures are connected to the y-axis rigid beam 9b and symmetrically distributed on both sides of the mass block 7b. Detection-drive decoupling beams 24a and 24b are symmetrical about the y-axis rigid beams 9a and 9b, respectively, and their endpoints are fixed to anchor points. Each set of comb tooth structures consists of movable comb teeth 21, driving comb teeth 22, and driving detection comb teeth 23, and is connected to the y-axis rigid beams 9a and 9b of the driving frame through the movable comb teeth 21. The detection structure includes an elliptical magnifying detection beam 11, detection sensitive beams 12a and 12b, a drive-detection decoupling beam 13a and 13b, a detection beam 14, a detection beam 15, and multiple sets of comb tooth structures. Two mass blocks 7a and 7b are connected to the top of the major semi-axis of the elliptical ring of the elliptical magnifying detection beam 11 via two detection sensitive beams 12a and 12b, respectively. Each set of comb tooth structures includes movable comb teeth and fixed comb teeth. The movable comb teeth are connected to the minor semi-axis of the elliptical ring of the elliptical magnifying detection beam 11 via... The shaft top end is connected and coupled, and the movable comb teeth and fixed comb teeth are staggered along the detection movement direction and do not contact each other; the detection beams 14 and 15 are connected to the movable comb teeth 20a and 20d in the comb tooth structure, respectively, and their ends are fixed to the anchor point; the drive-detection decoupling beams 13a and 13b are connected to the detection sensitive beams 12a and 12b, respectively, and their ends are fixed to the anchor point; the mass block in the detection mode is coupled to each other through the detection sensitive beams 12a and 12b, the amplified detection beam 11, and the detection beams 14 and 15.

[0008] Furthermore, when the two mass blocks, driving structure, and detection structure exceed one set, it also includes driving coupling beams 10a and 10b respectively installed on rigid beams 9a and 9b on the y-axis and located between each set of mass blocks, and the detection structure of each set is connected by beam 25.

[0009] Furthermore, the motion directions of any adjacent mass blocks are opposite.

[0010] Furthermore, the driving frame, mass block, driving structure, and detection structure are arranged symmetrically about the x-axis.

[0011] Furthermore, the driving frame, mass block, driving structure, and detection structure are arranged symmetrically about the y-axis.

[0012] Furthermore, the x-axis rigid beams 8a and 8b are fixed at anchor points 1a and 1b at the center of the drive frame and are connected by short beams.

[0013] Furthermore, the detection-drive decoupling beams 24a and 24b, detection beams 14 and 15, and drive-detection decoupling beams 13a and 13b are all fixed at the anchor points at the two ends of the beams.

[0014] It should be noted that, as a type of ellipse, the circular shape, and the aforementioned magnified detection beam 11 being circular, means that the displacement is magnified by a factor of 1, but it is still within the scope of protection of this application.

[0015] The technical solution provided by this utility model has the following beneficial technical effects: 1. A structure combining an elliptical ring structure and a comb structure is proposed to form a lever effect to amplify the displacement of the sensitive mode. The driving structure, detection structure and mass block are independent of each other. The driving structure is restricted by the driving frame lever and can only move in the driving direction. The detection structure is restricted by its supporting structure and can only move in the detection direction. The mass block has two degrees of freedom in the plane, which can achieve decoupling. The size of the key flexible beam is systematically adjusted instead of changing the topology, and the frequencies of the driving mode and the detection mode are tuned to the first three orders of the system. The frequency of the main parasitic mode is pushed to the fourth order or higher, thereby eliminating the parasitic mode between the driving mode and the sensitive mode, and improving the long-term and short-term zero-bias stability of the gyroscope.

[0016] 2. According to the technical solution of this utility model, each group uses at least two symmetrical large-area sensitive mass blocks, which has the advantage of decoupling the driving mode and the detection mode, and also has a large signal output gain.

[0017] 3. The use of symmetrical sensitive mass blocks and detection frames, as well as other symmetrical structures, enables differential detection. External interference is processed differentially, further ensuring sensitivity and anti-interference capability. Moreover, the symmetrical structure can effectively suppress manufacturing errors, thereby improving the stability of the gyroscope. Attached Figure Description

[0018] Figure 1 This utility model discloses a dual-mass structure for a MEMS gyroscope with amplitude amplification. Figure 2 This utility model discloses a four-mass block structure for a MEMS gyroscope with amplitude amplification. Wherein: 1a-anchor point, 1b-anchor point, 7a-mass block, 7b-mass block, 8a-x-axis rigid beam, 8b-x-axis rigid beam, 9a-y-axis rigid beam, 9b-y-axis rigid beam, 10a-drive coupling beam, 10b-drive coupling beam, 11-magnification detection beam, 12a-detection sensitive beam, 12b-detection sensitive beam, 13a-drive-detection decoupling beam, 13b-drive-detection decoupling beam, 14-detection beam, 15-detection beam, 20a-movable comb tooth, 20b-movable comb tooth, 24a-detection-drive decoupling beam, 24b-detection-drive decoupling beam, 21-movable comb tooth, 22-drive comb tooth, 23-drive detection comb tooth. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0020] Example 1 like Figure 1 As shown, a MEMS gyroscope structure with amplitude amplification is disclosed. The structure includes a drive frame, two mass blocks, a drive structure, and a detection structure. The drive frame consists of x-axis rigid beams 8a and 8b, and y-axis rigid beams 9a and 9b connected to the left and right ends of the x-axis rigid beams 8a and 8b, respectively. The drive frame is fixed to anchor points 1a and 1b. The y-axis rigid beams 9a and 9b connect to two mass blocks 7a and 7b, respectively. The x-axis rigid beams 8a and 8b are rigid in the x-axis direction and do not easily deform when force is applied in the x-direction, such as through compression and elongation. However, they are flexible in the y-axis direction, and deform when force is applied in the y-axis direction. Similarly, the y-axis rigid beams 9a and 9b are flexible in the x-direction but rigid in the y-direction.

[0021] The driving structure includes detection-drive decoupling beams 24a and 24b and multiple sets of comb tooth structures. Detection-drive decoupling beams 24a and comb tooth structures are connected to the y-axis rigid beam 9a and distributed on both sides of the mass block 7a. Detection-drive decoupling beams 24b and comb tooth structures are connected to the y-axis rigid beam 9b and symmetrically distributed on both sides of the mass block 7b. Detection-drive decoupling beams 24a and 24b are symmetrical about the y-axis rigid beams 9a and 9b, respectively, and their endpoints are fixed to anchor points. Each set of comb tooth structures consists of movable comb teeth 21, driving comb teeth 22, and driving detection comb teeth 23, and is connected to the y-axis rigid beams 9a and 9b of the driving frame through the movable comb teeth 21. The detection structure includes an elliptical magnifying detection beam 11, detection sensitive beams 12a and 12b, a drive-detection decoupling beam 13a and 13b, a detection beam 14, a detection beam 15, and multiple sets of comb tooth structures. Two mass blocks 7a and 7b are connected to the top of the major semi-axis of the elliptical ring of the elliptical magnifying detection beam 11 via two detection sensitive beams 12a and 12b, respectively. Each set of comb tooth structures includes movable comb teeth and fixed comb teeth. The movable comb teeth are connected to the minor semi-axis of the elliptical ring of the elliptical magnifying detection beam 11 via... The shaft top end is connected and coupled, and the movable comb teeth and fixed comb teeth are staggered along the detection movement direction and do not contact each other; the detection beams 14 and 15 are connected to the movable comb teeth 20a and 20d in the comb tooth structure, respectively, and their ends are fixed to the anchor point; the drive-detection decoupling beams 13a and 13b are connected to the detection sensitive beams 12a and 12b, respectively, and their ends are fixed to the anchor point; the mass block in the detection mode is coupled to each other through the detection sensitive beams 12a and 12b, the amplified detection beam 11, and the detection beams 14 and 15.

[0022] The working principle of the gyroscope in this embodiment is as follows: In this embodiment, the drive frame, as the main motion-bearing structure, performs in-plane reciprocating motion. Its motion principle is achieved by applying voltages of the same amplitude but opposite phase to the drive comb 22, thereby generating electrostatic forces in opposite directions. Under the action of electrostatic forces, the entire structure of the in-plane gyroscope resonates in the drive mode. When the entire structure resonates in the drive mode, the drive frame drives the mass block to also resonate. At this time, the adjacent mass blocks move in opposite directions. At the same time, the drive detection comb 23 can provide real-time feedback on the vibration state (frequency, phase, amplitude) of the mass block, enabling the drive system to start and maintain stable self-excited oscillation, keeping the vibration amplitude constant, thereby ensuring the stability of the generated Coriolis force and ensuring measurement accuracy.

[0023] Under a fixed driving mode frequency, if an external angular velocity is input, the mass block will generate a Coriolis force in the detection direction. Since adjacent mass blocks in the driving mode move in opposite directions, under the action of the Coriolis force, the mass blocks in the detection mode also move in opposite directions (according to the right-hand rule), generating left-right motion in the detection direction. This provides a basis for using differential detection technology, thereby amplifying the useful signal and suppressing common-mode interference. During the vibration of the elliptical amplification detection beam 11, the displacement of the mass block (along the minor axis of the central ellipse) is coupled to the displacement of the sensitive comb teeth (along the minor axis of the combined elliptical beam, parallel to the driving displacement direction). When the central elliptical ring reaches the resonant state, its maximum amplitude along the major and minor axes is approximated by the following formula: Ymax / Xmax = b / a; In the formula, b represents the major semi-axis, a represents the minor semi-axis, Ymax is the maximum displacement of the major semi-axis, and Xmax is the maximum displacement of the minor semi-axis, meaning the displacement of the major semi-axis is amplified by a factor of b / a. Under a fixed driving modal frequency, if an external angular velocity is input, the mass block will generate a Coriolis force in the detection direction. Under the action of the Coriolis force, the mass block will move in the detection direction. When the mass block is displaced under the action of the Coriolis force, the position of the moving comb tooth relative to the fixed comb tooth changes, resulting in a change in capacitance. This change in capacitance is converted into a voltage or current signal by a capacitance sensor and then processed by signal processing circuits (such as amplifiers, filters, analog-to-digital converters, etc.). Finally, the input angular velocity is calculated using a digital signal processing algorithm. During this process, due to the displacement coupling between the central elliptical ring and the sensitive comb tooth, and its amplifying effect, the vibration displacement of the sensitive comb tooth also increases by a factor of b / a, improving detection sensitivity and thus enhancing the gyroscope's zero-bias stability.

[0024] Furthermore, since the driving structure, detection structure, and mass block are independent of each other, the driving structure is restricted by the driving frame lever detection-driving decoupling beam and can only move along the driving direction. The detection structure is restricted by its supporting structure and the driving-detection decoupling beam and can only move along the detection direction. The mass block has two degrees of freedom in the plane, thus achieving decoupling. At the same time, the size of the key flexible beam is systematically adjusted rather than the topology is changed, the frequency of the driving mode and the detection mode is tuned to the first three orders of the system, and the frequency of the main parasitic mode is pushed to the fourth order or higher, thereby eliminating the parasitic mode between the driving mode and the sensitive mode. The driving mode and the detection mode can achieve the decoupling effect.

[0025] Example 2 like Figure 2 As shown, compared with Embodiment 1, the MEMS gyroscope structure with amplitude amplification provided in this embodiment is different in that it includes two groups of four mass blocks, two driving structures and a detection structure, and also includes driving coupling beams 10a and 10b respectively installed on rigid beams 9a and 9b on the y-axis and located between each group of mass blocks, and the detection structure of each group is connected by beam 25.

[0026] The working principle of the gyroscope structure in this embodiment is the same as that in Embodiment 1. In addition, it has the following technical effects: The four-mass block structure adopted in this embodiment has the advantage of decoupling the driving mode and the detection mode due to the use of a large-area sensitive mass block. At the same time, it also has a large signal output gain, which further improves the detection accuracy.

[0027] Example 3 Compared with Embodiments 1 and 2, the MEMS gyroscope structure with amplitude amplification provided in this embodiment differs in that, based on Embodiments 1 and 2, the driving frame, mass block, driving structure, and detection structure are arranged symmetrically about the x-axis.

[0028] Example 4 Compared with Embodiments 1, 2, and 3, the MEMS gyroscope structure with amplitude amplification provided in this embodiment differs in that, based on Embodiments 1, 2, and 3, the driving frame, mass block, driving structure, and detection structure are arranged symmetrically about the y-axis.

[0029] Example 5 Compared to Example 4, the MEMS gyroscope structure with amplitude amplification provided in this example differs in that: the x-axis rigid beams 8a and 8b are fixed at anchor points 1a and 1b at the center of the drive frame and are connected by short beams. The detection-drive decoupling beams 24a and 24b, detection beams 14 and 15, and drive-detection decoupling beams 13a and 13b are fixed at the anchor points at the two ends of the beams.

[0030] The gyroscope structures provided in Examples 3, 4, and 5 also have the following technical effects: they adopt a symmetrical structure, which enables differential detection, and the same external interference is processed differentially, further ensuring sensitivity and anti-interference ability; and the symmetrical structure can effectively suppress manufacturing errors, thereby improving the stability of the gyroscope.

[0031] It should be noted that in the above embodiments, the circle is one type of ellipse, and the magnified detection beam 11 is circular. At this time, the displacement is magnified by 1 time, but it is still within the protection scope of this application.

Claims

1. A MEMS gyroscope structure with amplitude amplification function, comprising a drive frame and at least one set of two mass blocks, a drive structure, and a detection structure, characterized in that: The drive frame consists of an x-axis rigid beam (8a) and (8b) and a y-axis rigid beam (9a) and (9b) connected to the left and right ends of the x-axis rigid beam (8a) and (8b) respectively. The x-axis rigid beam (8a) and (8b) drive the frame to be fixed on the anchor point; the y-axis rigid beam (9a) and (9b) are connected to two mass blocks (7a) and (7b) respectively. The driving structure includes a detection-drive decoupling beam (24a) and (24b) and multiple sets of comb tooth structures. The detection-drive decoupling beam (24a) and comb tooth structures are connected to the y-axis rigid beam (9a) and distributed on both sides of the mass block (7a). The detection-drive decoupling beam (24b) and comb tooth structures are connected to the y-axis rigid beam (9b) and symmetrically distributed on both sides of the mass block (7b). The detection-drive decoupling beams (24a) and (24b) are symmetrical about the y-axis rigid beams (9a) and (9b) and fixed at the anchor point. Each set of comb tooth structures consists of movable comb teeth (21), driving comb teeth (22) and driving detection comb teeth (23). The movable comb teeth (21) are connected to the y-axis rigid beams (9a) and (9b) of the driving frame. The detection structure includes an elliptical magnifying detection beam (11), detection sensitive beams (12a) and (12b), a drive-detection decoupling beam (13a) and (13b), a detection beam (14), a detection beam (15), and multiple sets of comb tooth structures, wherein: two mass blocks (7a) and (7b) are respectively connected to the top of the major semi-axis of the elliptical ring of the elliptical magnifying detection beam (11) through two detection sensitive beams (12a) and (12b); each set of comb tooth structures includes movable comb teeth and fixed comb teeth, the movable comb teeth being connected to the elliptical magnifying detection beam (11) through the drive-detection decoupling beam (13a) and (13b). The top of the short semi-axis of the elliptical ring is connected and coupled. The movable comb teeth and the fixed comb teeth are staggered along the detection motion direction and do not contact each other. The detection beam (14) and the detection beam (15) are respectively connected to the movable comb teeth in the comb tooth structure and fixed to the anchor point. The drive-detection decoupling beams (13a) and (13b) are respectively connected to the detection sensitive beams (12a) and (12b) and fixed to the anchor point. The mass block in the detection mode is coupled to each other through the detection sensitive beams (12a) and (12b), the amplified detection beam (11), and the detection beams (14) and (15).

2. The MEMS gyroscope structure with amplitude amplification effect according to claim 1, characterized in that: When the two mass blocks, driving structure, and detection structure are more than one set, the system also includes driving coupling beams (10a) and (10b) respectively installed on rigid beams (9a) and (9b) on the y-axis and located between each set of mass blocks, and the detection structures of each set are connected by beams (25).

3. The MEMS gyroscope structure with amplitude amplification function as described in claim 2, characterized in that: The directions of motion of any adjacent mass blocks are opposite.

4. The MEMS gyroscope structure with amplitude amplification effect of claim 3, wherein: The driving frame, mass block, driving structure, and detection structure are arranged symmetrically about the x-axis.

5. The MEMS gyroscope structure with amplitude amplification effect according to claim 1 or 2 or 3, characterized in that: The driving frame, mass block, driving structure, and detection structure are arranged symmetrically about the y-axis.

6. The MEMS gyroscope structure with amplitude amplification effect of claim 5, wherein: The x-axis rigid beams (8a) and (8b) are fixed at anchor points (1a) and (1b) at the center of the driving frame and are connected to the anchor points by short beams.

7. A MEMS gyroscope structure with amplitude amplification according to claim 6, characterized in that: The detection-drive decoupling beams (24a) and (24b), the detection beam (14), the detection beam (15), and the drive-detection decoupling beams (13a) and (13b) are fixed at the anchor points at the two ends of the beams.

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