A decoupled micromechanical gyroscope structure with adjustable orthogonal error

Abstract

A decoupled micromechanical gyroscope structure with adjustable orthogonal error comprises: a support frame, a drive frame, a sensor frame, and a detection mass block, wherein the support frame is used to provide a support foundation; the drive frame is arranged on the inner side of the support frame, and the corners of the drive frame are connected to the support frame through a drive assembly, and a comb tooth assembly is arranged between the outer side of the drive frame that is perpendicular to the drive direction and the support frame; the sensor frame is arranged on the inner side of the drive frame, and the two ends of the sensor frame that are symmetrical with the drive direction as the center are connected to the drive frame through a first sensor connection assembly; the detection mass block is arranged on the inner side of the sensor frame, and the two ends of the detection mass block that are symmetrical with the drive direction as the center are connected to the sensor frame through a second sensor connection assembly.

Description

Technical Field

[0001] The invention belongs to the technical field of micro-inertial navigation instrument measuring instrument parts, and in particular relates to a decoupled micro-mechanical gyroscope structure capable of adjusting orthogonal errors. Background Art

[0002] A gyroscope is a sensor used to measure angular rate and is one of the core components of inertial technology. It plays an important role in modern industrial control, aerospace, national defense and military, consumer electronics and other fields.

[0003] For micromechanical gyroscopes, the orthogonal error of the structure is an important factor affecting its performance. For gyroscopes with undecoupled structures, the mass block and the fixed end are connected by a two-dimensional elastic beam. The single mass block has two degrees of freedom, driving and detecting, and there is serious coupling between the modes. Decoupled gyroscopes can be divided into single decoupling and double decoupling. The single decoupling structure gyroscope only removes the coupling of the detection mode to the driving mode, and the driving mode will affect the detection mode. For double-stage decoupling structure gyroscopes, the driving mode does not affect the detection mode, and the detection mode does not affect the driving mode. The coupling error between the two modes can be eliminated, the influence of the orthogonal error can be reduced, and the accuracy of angular velocity signal detection can be improved. In actual process processing, due to the existence of process processing errors, there are errors between the theoretical structure and the actual processing structure, and the coupling situation is difficult to avoid. The present invention aims to reduce the orthogonal coupling error, and reduces the orthogonal coupling error through a reasonable and ingenious gyroscope structure design, which essentially reduces the influence of the coupling error on the performance of the micro gyroscope.

[0004] In addition, the micro-gyroscope in the present invention adopts electrostatic drive, which has many advantages such as good stability and precise control. The driving and detection directions in the structure each have one degree of freedom, realizing decoupling. The orthogonal error adjustment structure reduces the coupling of the driving to the detection direction caused by the process error, and more accurately detects the Coriolis force, while improving the zero bias stability of the gyroscope structure. Summary of the invention

[0005] The purpose of the present invention is to provide a decoupled micro-mechanical gyroscope structure device with adjustable orthogonal error in view of the shortcomings of the background technology, so that the micro-gyroscope has a small orthogonal coupling error and high detection accuracy.

[0006] The technical solution of the present invention is as follows:

[0007] A decoupled micromechanical gyroscope structure capable of adjusting orthogonal error comprises: a support frame, a driving frame, a sensing frame, and a detection mass block, wherein the support frame is used to provide a support foundation;

[0008] The driving frame is arranged inside the supporting frame, and the corners of the driving frame are connected to the supporting frame through a driving assembly, and a comb assembly is arranged between the outer side of the driving frame perpendicular to the driving direction and the supporting frame;

[0009] The sensing frame is arranged inside the driving frame, and two ends of the sensing frame symmetrically centered on the driving direction are connected to the driving frame through a first sensing connection assembly;

[0010] The detection mass block is arranged inside the sensor frame, and two ends of the detection mass block which are symmetrical with respect to the driving direction are connected to the sensor frame through a second sensor connection component.

[0011] Optionally, the comb tooth assembly includes: fixed comb teeth and movable comb teeth, the fixed comb teeth are arranged at equal intervals on the inner side of the support frame, the movable comb teeth are arranged at equal intervals on the outer side of the drive frame, and the fixed comb teeth and movable comb teeth are cross-matched.

[0012] Optionally, the first sensing connection component includes: a sensing frame connecting block and a sensing beam, one end of the sensing frame connecting block is connected to the inner wall of the driving frame, the other end of the sensing frame connecting block is connected to the middle of the sensing beam, and both ends of the sensing beam are respectively connected to the ends of the sensing frame.

[0013] Optionally, the second sensing connection component includes: a concave connection block, an orthogonal adjustment structure, a detection connection structure and a detection beam, the concave connection block has a first recessed portion, the orthogonal adjustment structure is arranged in the first recessed portion of the concave connection block, the detection mass block has a second recessed portion near the orthogonal adjustment structure, the detection beam is arranged in the second recessed portion along the driving direction, and both ends are respectively connected to the inner side walls of the recessed portion of the detection mass block, the orthogonal adjustment structure is connected to the middle part of the detection beam, the detection connection structure is symmetrically arranged on both sides of the concave connection block, and the detection connection structure is respectively connected to the sensing frame, the concave connection block and the detection mass block.

[0014] Optionally, the orthogonal adjustment structure includes: fixed adjustment comb teeth, movable adjustable comb teeth, a fixed comb tooth connecting block and an orthogonal adjustment connecting block, one end of the orthogonal adjustment connecting block is connected to the middle part of the detection beam, and the other end of the orthogonal adjustment connecting block is connected to the fixed comb tooth connecting block, the fixed adjustment comb teeth are respectively connected to both sides of the fixed comb tooth connecting block along the driving direction, the movable adjustable comb teeth are connected to the inner wall of the first recessed portion on the concave connecting block along the driving direction corresponding to the position of the fixed comb tooth connecting block, and the movable adjustable comb teeth are staggered with the fixed adjustment comb teeth.

[0015] Optionally, the driving component includes: a first driving elastic beam, a second driving elastic beam, a driving connecting block and a driving connecting beam, the driving connecting beam is arranged at one end of the driving connecting block, the first driving elastic beam and the second driving elastic beam are respectively arranged on both sides of the driving connecting block and one end is respectively connected to the driving connecting beam, the other ends of the first driving elastic beam and the second driving elastic beam are respectively connected to the driving frame, and the other end of the driving connecting block is connected to the support frame.

[0016] Optionally, the detection connection structure includes: a first detection elastic beam, a second detection elastic beam, a detection connection block and a detection connection beam, the detection connection beam is arranged at one end of the detection connection block, the first detection elastic beam and the second detection elastic beam are respectively arranged on both sides of the detection connection block and one end is respectively connected to the detection connection beam, the first detection elastic beam is connected to the sensor frame, the second detection elastic beam is connected to the concave connection block at the other end, and the other end of the detection connection block is connected to the detection mass block.

[0017] The micromechanical gyroscope structure of the present invention has a symmetrical overall structure, and the driving direction and the detection direction are decoupled respectively, and the orthogonal error can be adjusted. The structure is reasonable and compact, and the structure has the advantages of good zero bias stability and good reliability.

[0018] The present invention provides a decoupled micromechanical gyroscope structure device with adjustable orthogonal error. The overall structure is reasonable and compact, the orthogonal coupling error is small, and electrostatic drive is adopted. The electrostatic drive has many advantages such as good stability and precise control. In the structure, the driving direction and the detection direction each have a degree of freedom to achieve decoupling. The orthogonal error adjustment structure reduces the coupling of the driving direction to the detection direction caused by the process error, and the Coriolis force is detected more accurately, while the zero bias stability of the gyroscope structure is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The advantages of the above and / or additional aspects of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0020] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0021] Figure 2 It is a top view schematic diagram of the overall structure of the present invention;

[0022] Figure 3 It is a top view schematic diagram of the orthogonal adjustment structure of the present invention;

[0023] Figure 4 This is a schematic diagram of the structure of the drive assembly of the present invention;

[0024] Figure 5 It is a schematic diagram of the detection connection structure of the present invention.

[0025] As shown in the figures, the list of reference numerals is as follows:

[0026] Support frame-1, fixed comb teeth-2, 24, movable comb teeth-3, 25, driving components-4, 6, 7, 10, driving frame-5, sensing frame-8, detection mass block-9, detection connection structure-11, 12, 16, 19, orthogonal adjustment structure-13, 18, sensing frame connection block-14, 17, sensing beam-15, 20, detection beam-21, 26, concave connection block-22, 23, first driving elastic beam-27, second driving elastic beam-28, driving connection block-29, driving connection beam-30, fixed adjustment comb teeth-31, 32, movable adjustment comb teeth-33, 34, fixed comb teeth connection block-35, orthogonal adjustment connection block-36, first detection elastic beam-37, second detection elastic beam-37a, detection connection block-38, detection connection beam-39. DETAILED DESCRIPTION

[0027] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0028] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by the terms "center", "up", "down", "front", "back", "left", "right", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0029] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] The present invention will be further described below in conjunction with the accompanying drawings:

[0031] like Figure 1 , 2As shown, a decoupled micromechanical gyroscope structure with adjustable orthogonal error includes: a support frame 1, a driving frame 5, a sensor frame 8, and a detection mass block 9, wherein the support frame 1 is used to provide a support foundation;

[0032] The driving frame 5 is arranged inside the supporting frame 1, and the corners of the driving frame 5 are connected to the supporting frame 1 through driving components 4, 6, 7, and 10, and a comb tooth component is arranged between the outer side of the driving frame 5 perpendicular to the driving direction and the supporting frame 1;

[0033] The sensing frame 8 is arranged inside the driving frame 5, and two ends of the sensing frame 8 symmetrically centered about the driving direction are connected to the driving frame 5 through a first sensing connection assembly;

[0034] The detection mass block 9 is arranged inside the sensor frame 8 , and two ends of the detection mass block 9 symmetrically centered about the driving direction are connected to the sensor frame 8 through a second sensor connection assembly.

[0035] like Figure 1 , 2 As shown, the inner side of the support frame 1 has a space for installing the drive frame 5, the drive frame 5 is arranged inside the support frame 1, and the corners of the drive frame 5 are provided with grooves for accommodating the drive components 4, 6, 7, and 10. The drive frame 5 is connected to the support frame 1 through the drive components 4, 6, 7, and 10.

[0036] like Figure 1 , 2 As shown, the comb teeth assembly is arranged between the outer side of the driving frame 5 perpendicular to the driving direction and the support frame 1, that is, between the outer side of the driving frame 5 perpendicular to the X-axis direction and the support frame 1 in this embodiment, the comb teeth assembly includes: fixed comb teeth 2, 24 and movable comb teeth 3, 25, the fixed comb teeth 2, 24 are arranged on the inner side of the support frame 1 at equal intervals, the movable comb teeth 3, 25 are arranged on the outer side of the driving frame 5 at equal intervals, and the fixed comb teeth 2, 24 and the movable comb teeth 3, 25 are cross-matched. The movable comb teeth 3, 25 cross-match with the fixed comb teeth 2, 24, which can accurately control the drive and is easy to implement. The number of comb teeth can be appropriately increased or decreased according to the required driving force. The comb teeth drive speed is fast, the power consumption is low, the compatibility is good, the required driving current is small, the manufacturing is simple, and the reliability is high. During driving, due to the electrostatic force between the movable comb teeth 3, 25 and the fixed comb teeth 2, 24, the driving frame 5 moves along the X-axis direction under the action of the driving components 4, 6, 7, 10.

[0037] like Figure 1 , 2As shown, the sensing frame 8 is arranged inside the driving frame 5 and connected to the driving frame 5 through a first sensing connection component. The first sensing connection component is located at two ends of the sensing frame 8 that are symmetrical with the driving direction as the center and at two ends that are symmetrical with the X-axis as the center.

[0038] like Figure 1 , 2 As shown, the first sensing connection assembly includes: sensing frame connecting blocks 14, 17 and sensing beams 15, 20, one end of the sensing frame connecting blocks 14, 17 is connected to the inner wall of the driving frame 5, the other end of the sensing frame connecting blocks 14, 17 is connected to the middle of the sensing beams 15, 20, and the two ends of the sensing beams 15, 20 are respectively connected to the ends of the sensing frame 8.

[0039] like Figure 1 , 2 The detection mass block 9 is arranged at the center of the sensing frame 8 and connected to the sensing frame 8 via a second sensing connection assembly. The second sensing connection assembly is located at two ends of the detection mass block 9 that are symmetrical around the driving direction, that is, two ends that are symmetrical around the X-axis.

[0040] like Figure 1 , 2 As shown, the second sensing connection component includes: concave connection blocks 22, 23, orthogonal adjustment structures 13, 18, detection connection structures 11, 12, 16, 19 and detection beams 21, 26, the concave connection blocks 22, 23 have a first concave portion, the orthogonal adjustment structures 13, 18 are arranged in the first concave portions of the concave connection blocks 22, 23, the detection mass block 9 has a second concave portion near the orthogonal adjustment structures 13, 18, the detection beams 21, 26 are arranged in the second concave portion along the driving direction, and the two ends are respectively connected to the inner side walls of the concave portion of the detection mass block 9, the orthogonal adjustment structures 13, 18 are connected to the middle parts of the detection beams 21, 26, the detection connection structures 11, 12, 16, 19 are symmetrically arranged on both sides of the concave connection blocks 22, 23, and the detection connection structures 11, 12, 16, 19 are respectively connected to the sensing frame 8, the concave connection blocks 22, 23 and the detection mass block 9.

[0041] like Figure 1 , 2As shown in Figure 3, the orthogonal adjustment structure 13, 18 includes: fixed adjustment comb teeth 31, 32, movable adjustment comb teeth 33, 34, a fixed comb tooth connecting block 35 and an orthogonal adjustment connecting block 36, one end of the orthogonal adjustment connecting block 36 is connected to the middle of the detection beams 21, 26, and the other end of the orthogonal adjustment connecting block 36 is connected to the fixed comb tooth connecting block 35, the fixed adjustment comb teeth 31, 32 are respectively connected to the two sides of the fixed comb tooth connecting block 35 along the driving direction, the movable adjustable comb teeth 33, 34 are connected to the inner wall of the first inner recess on the concave connecting blocks 22, 23 along the driving direction corresponding to the position of the fixed comb tooth connecting block 35, and the movable adjustable comb teeth 33, 34 are staggered with the fixed adjustment comb teeth 31, 32. When the driving frame 5 moves along the driving direction, the sensing frame 8, the detection connecting structure 11, 12, 16, 19 and the concave connecting blocks 22, 23 are driven to move along the driving direction through the sensing connecting block. Due to the process error, the driving direction has a motion component in the detection direction. The orthogonal adjustment structure 13, 18 offsets the driving motion component in the detection direction through the electrostatic force between the fixed adjustment comb teeth 31, 32 and the movable adjustment comb teeth 33, 34, thereby reducing the structural orthogonal error and improving the zero bias stability of the structure.

[0042] like Figure 2 , 4 As shown, the driving components 4, 6, 7, 10 and the detection connection structures 11, 12, 16, 19 are the same in structure, that is, they are all folded beam structures, and the folded beam structures are thin strip beam structures, and their size can be determined according to the application environment and the stiffness coefficient.

[0043] like Figure 2 , 4 As shown, the driving components 4, 6, 7, 10 include: a first driving elastic beam 27, a second driving elastic beam 28, a driving connection block 29 and a driving connection beam 30. The driving connection beam 30 is arranged at one end of the driving connection block 29, and the first driving elastic beam 27 and the second driving elastic beam 28 are respectively arranged on both sides of the driving connection block 29 and one end is respectively connected to the driving connection beam 30. The other ends of the first driving elastic beam 27 and the second driving elastic beam 28 are respectively connected to the driving frame 5, and the other end of the driving connection block 29 is connected to the support frame 1.

[0044] like Figure 5The detection connection structure 11, 12, 16, 19 includes: a first detection elastic beam 37, a second detection elastic beam 37a, a detection connection block 38 and a detection connection beam 39. The detection connection beam 39 is arranged at one end of the detection connection block 38, and the first detection elastic beam 37 and the second detection elastic beam 37a are respectively arranged on both sides of the detection connection block 38 and one end is respectively connected to the detection connection beam 39. The first detection elastic beam 37 is connected to the sensor frame 8, the second detection elastic beam 37a is connected to the concave connection blocks 22 and 23 at the other end, and the other end of the detection connection block 38 is connected to the detection mass block 9.

[0045] The principle of the present invention is as follows:

[0046] The driving frame resonates in the X direction under the precise control of the electrostatic force between the movable comb teeth and the fixed comb teeth. The driving frame drives the sensing frame to move along the driving direction through the first sensing connection component. The detection connection structure and the concave connection block move with the sensing frame. The fixed adjustment comb teeth, the fixed comb teeth connection block and the orthogonal adjustment connection block in the orthogonal adjustment structure do not move along the X direction due to fixation. The detection mass block does not move along the X direction under the fixing action of the orthogonal adjustment connection block.

[0047] Due to the unavoidable reasons of processing errors, when driving, the driving component drives the driving frame, the first sensing connection component, the sensing frame, the concave connection block and the detection connection structure, and does not move strictly along the X-axis, but moves along an axis at a certain angle to the X-axis direction; the detection mass block is fixed in the X direction by the orthogonal adjustment structure, and its X-direction degree of freedom is 0, and the Y-direction degree of freedom is 1, which realizes the decoupling of the detection direction, but it will be displaced in the Y direction under the non-X-axis movement of the connection structure, which is the fundamental reason for the zero bias stability of all gyro structures. The orthogonal adjustment structure can adjust the gyro drive axis to the X-axis through electrostatic adjustment, and limit the displacement of the detection mass block in the Y direction under drive, thereby fundamentally eliminating the zero bias. When there is an angular velocity input from the outside, the detection mass block transmits the action through the sensing frame to realize the detection of the Coriolis force and the displacement generated in the Y direction. The sensing frame does not strictly sense along the Y direction. Due to the asymmetry of the beam structure, the sensing direction is at a certain angle to the Y axis. However, due to the fixed effect of the orthogonal adjustment structure in the X direction, the sensing direction is along the Y direction. There is no motion component in the X axis, so the detection direction is decoupled, avoiding the influence of the detection on the driving direction, thereby reducing the nonlinear behavior of the driving direction.

[0048] When there is an angular velocity input in the Z direction, due to the action of the Coeur force, the sensor frame will drive the detection connection structure, the concave connection block, and the detection mass block to vibrate along the Y direction, and the angular velocity information can be obtained by detecting the displacement of the detection mass block.

[0049] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0050] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A decoupled micromechanical gyroscope structure with adjustable orthogonal error, characterized in that: include: A support frame (1), a driving frame (5), a sensing frame (8), and a detection mass block (9), wherein the support frame (1) is used to provide a supporting foundation; The driving frame (5) is arranged on the inner side of the supporting frame (1); the corners of the driving frame (5) are connected to the supporting frame (1) via driving components (4, 6, 7, 10); and a comb tooth component is arranged between the outer side of the driving frame (5) perpendicular to the driving direction and the supporting frame (1); The sensing frame (8) is arranged inside the driving frame (5), and two ends of the sensing frame (8) symmetrically around the driving direction are connected to the driving frame (5) via a first sensing connection assembly; The detection mass block (9) is arranged inside the sensing frame (8), and two ends of the detection mass block (9) symmetrically centered about the driving direction are connected to the sensing frame (8) via a second sensing connection assembly; The comb teeth assembly comprises: fixed comb teeth (2, 24) and movable comb teeth (3, 25), wherein the fixed comb teeth (2, 24) are arranged at equal intervals on the inner side of the support frame (1), and the movable comb teeth (3, 25) are arranged at equal intervals on the outer side of the drive frame (5), and the fixed comb teeth (2, 24) and the movable comb teeth (3, 25) are cross-matched; The second sensing connection assembly comprises: a concave connection block (22, 23), an orthogonal adjustment structure (13, 18), a detection connection structure (11, 12, 16, 19) and a detection beam (21, 26), wherein the concave connection block (22, 23) has a first inner concave portion, the orthogonal adjustment structure (13, 18) is arranged in the first inner concave portion of the concave connection block (22, 23), the detection mass block (9) has a second inner concave portion near the orthogonal adjustment structure (13, 18), and the detection beam ( The detection beams (21, 26) are arranged in the second inner recess along the driving direction, and the two ends are respectively connected to the inner side walls of the inner recess of the detection mass block (9), the orthogonal adjustment structure (13, 18) is connected to the middle of the detection beams (21, 26), the detection connection structures (11, 12, 16, 19) are symmetrically arranged on both sides of the concave connection blocks (22, 23), and the detection connection structures (11, 12, 16, 19) are respectively connected to the sensing frame (8), the concave connection blocks (22, 23) and the detection mass block (9).

2. The decoupled micromechanical gyroscope structure with adjustable orthogonal error according to claim 1, characterized in that: The first sensing connection assembly comprises: a sensing frame connection block (14, 17) and a sensing beam (15, 20), wherein one end of the sensing frame connection block (14, 17) is connected to the inner wall of the driving frame (5), the other end of the sensing frame connection block (14, 17) is connected to the middle of the sensing beam (15, 20), and both ends of the sensing beam (15, 20) are respectively connected to the end of the sensing frame (8).

3. The decoupled micromechanical gyroscope structure with adjustable orthogonal error according to claim 1, characterized in that: The orthogonal adjustment structure (13, 18) comprises: fixed adjustment comb teeth (31, 32), movable adjustment comb teeth (33, 34), a fixed comb tooth connection block (35) and an orthogonal adjustment connection block (36); one end of the orthogonal adjustment connection block (36) is connected to the middle of the detection beam (21, 26); the other end of the orthogonal adjustment connection block (36) is connected to the fixed comb tooth connection block (35); the fixed adjustment comb teeth (31, 32) are respectively connected to both sides of the fixed comb tooth connection block (35) along the driving direction; the movable adjustment comb teeth (33, 34) are connected to the inner wall of the first inner concave part of the concave connection block (22, 23) along the driving direction corresponding to the position of the fixed comb tooth connection block (35); the movable adjustment comb teeth (33, 34) and the fixed adjustment comb teeth (31, 32) are staggered.

4. The decoupled micromechanical gyroscope structure with adjustable orthogonal error according to claim 1, characterized in that: The driving assembly (4, 6, 7, 10) comprises: a first driving elastic beam (27), a second driving elastic beam (28), a driving connection block (29) and a driving connection beam (30); the driving connection beam (30) is arranged at one end of the driving connection block (29); the first driving elastic beam (27) and the second driving elastic beam (28) are respectively arranged on both sides of the driving connection block (29) and one end is respectively connected to the driving connection beam (30); the other ends of the first driving elastic beam (27) and the second driving elastic beam (28) are respectively connected to the driving frame (5); and the other end of the driving connection block (29) is connected to the supporting frame (1).

5. The decoupled micromechanical gyroscope structure with adjustable orthogonal error according to claim 1, characterized in that: The detection connection structure (11, 12, 16, 19) comprises: a first detection elastic beam (37), a second detection elastic beam (37a), a detection connection block (38) and a detection connection beam (41); the detection connection beam (41) is arranged at one end of the detection connection block (38); the first detection elastic beam (37) and the second detection elastic beam (37a) are respectively arranged on both sides of the detection connection block (38) and one end is respectively connected to the detection connection beam (41); the first detection elastic beam (37) is connected to the sensing frame (8); the second detection elastic beam (37a) is connected to the concave connection blocks (22, 23) at the other end; and the other end of the detection connection block (38) is connected to the detection mass block (9).

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