Disclosure of Invention
The invention aims to provide an in-plane sensitive axis micromechanical gyroscope based on a lever structure.
In order to achieve the above object, the present invention provides an in-plane sensitive axis micromechanical gyroscope based on a lever structure, including: the lever-type decoupling units are connected with the coupling units;
the lever type decoupling unit includes: the device comprises a driving mass block, a detection mass block, a decoupling structure, a driving structure and a detection electrode;
the driving mass block and the detection mass block are arranged adjacently at intervals and are fixedly connected with two ends opposite to the decoupling structure respectively;
the decoupling structure is a lever-type decoupling structure and can generate elastic deformation perpendicular to the axial direction under the action of external force;
the driving structure is connected with the driving mass block, and the detection electrode is arranged under the detection mass block.
According to one aspect of the invention, a plurality of the lever-type decoupling units are arrayed in a regular multi-row mode, and adjacent lever-type decoupling units are in mirror symmetry.
According to one aspect of the invention, the decoupling structure comprises: a drive lever portion, a detection lever portion and a lever fulcrum beam;
the driving lever part and the detection lever part are respectively and fixedly connected with the lever fulcrum beam and are respectively positioned at two opposite sides of the lever fulcrum beam;
the drive lever portion has a bending rigidity smaller than that of the detection lever portion.
According to an aspect of the present invention, the decoupling structure is a flat structure, and the driving lever portion has a bending rigidity in a thickness direction larger than a bending rigidity in a width direction, and the detecting lever portion has a bending rigidity in a thickness direction larger than a bending rigidity in a width direction.
According to an aspect of the present invention, the driving lever portion includes: a plurality of drive lever beams arranged in an array on the fulcrum beams at intervals in an axial direction of the fulcrum beams; wherein the bending stiffness of the driving lever portion is adjusted by adjusting at least one of the size, the sectional shape, the setting interval, and the setting number of the driving lever beam;
the detection lever portion includes: a plurality of detection lever beams arranged in an array at equal intervals in an axial direction of the lever fulcrum beam; wherein the bending rigidity of the driving lever portion is adjusted by adjusting at least one of a size, a sectional shape, a setting interval, and a setting number of the detection lever beam.
According to one aspect of the invention, the two axial ends of the lever fulcrum beam are respectively provided with a connecting anchor point;
the connecting anchor point is connected with the driving mass block through an elastic beam.
According to one aspect of the invention, the driving mass and the detection mass are both flat structures and are in the same plane with the decoupling structure;
the detection mass blocks of the lever-type decoupling units are elastically connected with each other;
the driving mass blocks of the lever-type decoupling units are elastically connected with each other.
According to one aspect of the invention, the driving structures are arranged on two opposite sides of the driving mass block of each lever-type decoupling unit;
the driving structure is used for driving the driving mass to move back and forth along the direction parallel to the decoupling structure.
According to one aspect of the invention, the number of the lever-type decoupling units is four;
the coupling unit includes: the first connecting beam, the second connecting beam, the third connecting beam and the coupling anchor point;
the first connecting beam is a rod-shaped beam and is arranged on the outer side of the in-plane sensitive axis micromechanical gyroscope;
elastic connecting parts are arranged at the end parts and the middle parts of the first connecting beams, the elastic connecting parts at the end parts are used for connecting the driving structures on the driving mass blocks arranged at intervals, and the elastic connecting parts at the middle parts are used for connecting the adjacent detection mass blocks;
the second connecting beam is an elastic beam and is used for connecting the driving structures on the adjacent driving mass blocks;
the third connecting beam is an elastic beam, is arranged in the middle of the in-plane sensitive axis micromechanical gyroscope and is used for connecting the adjacent detection mass blocks;
the coupling anchor points are provided with elastic connecting structures and are connected with the adjacent detection mass blocks through the elastic connecting structures;
the coupling anchor point is located between the third connecting beam and the first connecting beam.
According to an aspect of the present invention, the second connection beam includes: the elastic connecting device comprises elastic rhombic connecting frames and elastic beams arranged at two ends of the rhombic connecting frames in the length direction;
two ends of the rhombic connecting frame in the width direction are connected with the adjacent driving structures, and two opposite ends of the elastic beam are connected with the adjacent driving structures;
the driving structure drives the driving mass block by adopting a horizontal electrostatic force generated by the comb tooth structure.
According to one scheme of the invention, the decoupling structure not only realizes decoupling of the driving mode and the detection mode of the in-plane gyroscope, but also improves the signal-to-noise ratio of the in-plane sensitive axis micro-mechanical gyroscope through the amplification effect of the lever.
According to one scheme of the invention, the overall structure of the invention is composed of a plurality of symmetrical lever-type decoupling units, and the lever-type decoupling units are connected through the coupling units to realize differential motion, thereby effectively eliminating the influence of external environment and improving the stability.
According to one scheme of the invention, the lever type decoupling structure adopts the multi-beam levers with different bending rigidities (realized by changing the beam width, the section shape and the like) in the design of the driving lever part and the detection lever part, so that the bending rigidity of the driving lever part in the horizontal direction is reduced, and the bending rigidity in the normal direction is increased. Meanwhile, through the isolation effect of the lever fulcrum beam supported by the anchor point, the horizontal displacement of the detection lever part caused by the horizontal bending of the driving lever part is greatly reduced, and thus the modal decoupling is more effectively realized.
According to one scheme of the invention, because the normal bending rigidity of the driving lever part and the detection lever part in the decoupling structure is higher, the normal direction displacement of the driving mass block can be transmitted to the detection mass block, and the detection of the angular velocity is effectively realized.
According to one scheme of the invention, the lever has the displacement amplification effect, so that the decoupling structure can realize amplification of detection displacement by reasonably designing the proportion of the moment arm of the driving lever part and the moment arm of the detection lever part, and the normal displacement of the detection mass block is improved, thereby improving the signal-to-noise ratio of the decoupling structure.
According to one scheme of the invention, the in-plane sensitive axis micromechanical gyroscope is based on the principles of comb electrostatic driving and plate capacitance detection. Four symmetrical large-area sensitive mass blocks are adopted, and the device has the advantages of high sensitivity and strong anti-interference capability. The structure has the advantages of decoupling of the driving mode and the detection mode, and can effectively inhibit the mode coupling error caused by the machining error, so that the stability of the gyroscope is improved.
According to one scheme of the invention, the specific decoupling structure of the invention can realize the modal decoupling of the MEMS in-plane gyroscope. By designing the horizontal bending rigidity and the normal bending rigidity of the multi-beam, the decoupling in the horizontal direction and the coupling in the normal direction are realized.
Detailed Description
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.
In describing embodiments of the present invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship that is based on the orientation or positional relationship shown in the associated drawings, which is for convenience and simplicity of description only, and does not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus, the above-described terms should not be construed as limiting the present invention.
The present invention is described in detail below with reference to the drawings and the specific embodiments, which are not repeated herein, but the embodiments of the present invention are not limited to the following embodiments.
Referring to fig. 1 and 2, according to an embodiment of the present invention, an in-plane sensitive axis micromechanical gyroscope based on a lever structure includes: the device comprises a plurality of lever-type decoupling units 1 and a coupling unit 2 connected with the lever-type decoupling units 1. In the present embodiment, the lever type decoupling unit 1 includes: the device comprises a driving mass block 11, a detection mass block 12, a decoupling structure 13, a driving structure 14 and detection electrodes; the driving mass block 11 and the detection mass block 12 are arranged adjacently at intervals, and two ends opposite to the decoupling structure 13 are respectively and fixedly connected; the decoupling structure 13 is a lever-type decoupling structure, and can generate elastic deformation perpendicular to the axial direction under the action of external force; the driving structure 14 is connected to the driving mass 11, and the detection electrodes are disposed directly below the detection mass 12.
In the present embodiment, the detection electrode is disposed on one side of the proof mass 12, and the detection electrode is made of a single silicon wafer and forms a capacitor structure with a gap between the detection electrode and the proof mass 12. When the detection mass block 12 changes, the capacitance structure formed changes, so that the detection of the motion of the detection mass block 12 can be realized. In the present embodiment, the gap between the detection electrode and the proof mass 12 may be set to 2 μm.
As shown in fig. 1, according to one embodiment of the present invention, a plurality of lever-type decoupling units 1 are regularly arrayed in multiple rows, and adjacent lever-type decoupling units 1 are mirror-symmetrical. In the present embodiment, the number of the lever-type decoupling units 1 is four; the two lever type decoupling units 1 are arranged side by side, the lever type decoupling units 1 are arranged symmetrically, and the two rows of lever type decoupling units 1 are also arranged symmetrically.
As shown in fig. 1 and 2, according to one embodiment of the present invention, the decoupling structure 13 includes: a driving lever portion 131, a detecting lever portion 132, and a fulcrum beam 133. In the present embodiment, the driving lever portion 131 and the detecting lever portion 132 are respectively fixedly connected to the lever fulcrum beam 133 and respectively located at two opposite sides of the lever fulcrum beam 133. In the present embodiment, the bending rigidity of the driving lever portion 131 is smaller than that of the detecting lever portion 132.
As shown in fig. 1 and 2, according to one embodiment of the present invention, the decoupling structure 13 is a flat structure, and the bending stiffness in the thickness direction (i.e., the normal direction) of the driving lever portion 131 is greater than the bending stiffness in the width direction (i.e., the horizontal direction), and the bending stiffness in the thickness direction (i.e., the normal direction) of the detecting lever portion 132 is greater than the bending stiffness in the width direction (i.e., the horizontal direction).
As shown in fig. 1 and 2 in combination, according to an embodiment of the present invention, the actuating lever portion 131 includes: a plurality of driving lever beams 1311, the driving lever beams 1311 being arranged in a row on the fulcrum beams 133 at intervals in the axial direction of the fulcrum beams 133; in this embodiment, a cross beam may be further disposed at one end of the driving lever beam 1311 away from the fulcrum beam 133 to connect with the end of all the driving lever beams 1311, and further fixed to the driving mass 11 through the cross beam. In the present embodiment, the bending rigidity of the driving lever portion 131 is adjusted by adjusting at least one of the size, the sectional shape, and the setting interval of the driving lever beam 1311;
in the present embodiment, the detection lever portion 132 includes: a plurality of detection lever beams 1321, the detection lever beams 1321 being arranged on the lever fulcrum beam 133 at equal intervals in the axial direction of the lever fulcrum beam 133; in this embodiment, a cross beam may be further provided at one end of the detection lever beam 1321 away from the fulcrum beam 133 to be connected to the end of all the detection lever beams 1321, and further fixed to the proof mass 12 by the cross beam. Wherein the bending rigidity of the driving lever portion 131 is adjusted by adjusting at least one of the size, the sectional shape, and the arrangement interval of the detection lever beam 1321.
In the present embodiment, the width of the sensing lever part 132 is larger than that of the driving lever part 131, that is, the maximum spacing distance of the sensing lever beams 1321 in the sensing lever part 132 is larger than that of the driving lever beams 1311. Meanwhile, the number of the detection lever beams 1321 may be set to be larger than that of the driving lever beams 1311, and the size (e.g., thickness) of the detection lever beams 1321 may be set to be larger than that of the driving lever beams 1311.
As shown in fig. 1 and 2, according to an embodiment of the present invention, the lever fulcrum beam 133 is provided with connection anchors 1331 at two axial ends thereof, and in this embodiment, the connection anchors 1331 are connected to the driving mass 11 through elastic beams 1331 a. In the present embodiment, the lever fulcrum beam 133 is not in direct contact with the driving mass 11, it functions to connect the driving lever portion 131 and the detection lever portion 132, and it is connected to the driving mass 11 through the anchor point and the elastic beam 1331a provided at the end. In the present embodiment, the driving mass 11 is a flat structure with a hollow structure inside, and includes two driving mass portions a arranged at intervals, the fulcrum beam 133 is horizontally located between the intervals of the two driving mass portions, and the two driving mass portions a are connected to each other through the connecting arm b at the edge position. The anchor point 1331, when provided at the end of the fulcrum beam 133, is also not in contact with the two drive mass portions a, but is interconnected to the connecting arm b only by the spring beam 1331 a. In the present embodiment, the elastic beam 1331a is a meandering beam.
Referring to fig. 1 and 2, according to an embodiment of the present invention, the driving mass 11 and the proof mass 12 are both flat structures and are in the same plane with the decoupling structure 13; in the present embodiment, the proof masses 12 of the lever-type decoupling units 1 are elastically connected to each other; the driving masses 11 of the lever-type decoupling units 1 are elastically connected to one another. In the present embodiment, the proof masses 12 of the lever-type decoupling units 1 are elastically connected to each other through anchor points (provided with elastic connection structures) or elastic beams, so that relative elastic motion can be generated between the proof masses 12.
As shown in fig. 1, according to one embodiment of the present invention, the driving mass 11 of each lever-type decoupling unit 1 is provided with driving structures 14 on opposite sides; in this embodiment, the drive structure 14 is used to drive the drive mass 11 to move back and forth in a direction parallel to the decoupling structure 13. In the present embodiment, the driving structure 14 drives the driving mass 11 using the horizontal electrostatic force generated by the comb-tooth structure. The respectively connected drive masses 11 can be pushed in a horizontal direction by means of the drive structure 14 provided for movement.
As shown in fig. 1, according to an embodiment of the present invention, a coupling unit 2 includes: a first connecting beam 21, a second connecting beam 22, a third connecting beam 23 and a coupling anchor point 24. In the present embodiment, the second connecting beams 22 are elastic beams for connecting the driving structures 14 on the left and right adjacent driving masses 11. In the present embodiment, the first connecting beam 21 is a rod-shaped beam, which is disposed on the outermost side of the left and right sides of the in-plane sensitive axis micromechanical gyroscope, and is provided with elastic connecting portions 211 at the end and the middle positions thereof, the elastic connecting portions 211 at the end positions thereof are used for connecting the driving structures 14 on the driving masses 11 disposed at intervals, and the elastic connecting portions 211 at the middle position thereof are used for connecting the adjacent detection masses 12. In the present embodiment, the third connecting beam 23 is an elastic beam, which is disposed at the middle position of the in-plane sensitive axis micromechanical gyroscope and is used for connecting adjacent proof masses 12; because the combined mode of the four lever-type decoupling units 1 is adopted in the embodiment, the third connecting beam 23 at the middle position can be just connected with the four detection mass blocks 12. In the present embodiment, the coupling anchor points 24 are provided with elastic connection structures, and are connected with the adjacent detection mass blocks 12 through the elastic connection structures; in this embodiment, the coupling anchor points 24 are used to connect the middle positions of the proof masses 12 on the upper and lower sides, and the coupling anchor points 24 are located between the third connecting beams 23 and the first connecting beams 21.
As shown in fig. 1, according to an embodiment of the present invention, the second connection beam 22 includes: an elastic rhombic connection frame 221, and elastic beams 222 provided at both ends of the rhombic connection frame 221 in the longitudinal direction; in this embodiment, the diamond-shaped connecting frame 221 is a symmetrical diamond-shaped frame structure with a length greater than a width. In the present embodiment, both ends of the diamond-shaped link 221 in the width direction are connected to the adjacent driving structures 14, and both opposite ends of the elastic beam 222 are connected to the adjacent driving structures 14. In the present embodiment, the elastic beam 222 is a rod-shaped structure, and is disposed parallel to each other at both ends of the diamond-shaped connecting frame 221 in the longitudinal direction, and the end of the diamond-shaped connecting frame 221 is connected to the middle of the elastic beam 222.
Through the arrangement, the second connecting beam 22 adopts a combined structure of the diamond connecting frame and the elastic beam to form a diamond coupling structure, the diamond coupling structure has the advantages that the frequencies of the anti-phase differential motion mode and the in-phase motion mode of the driving mass block are separated, the gyroscope needs the anti-phase differential motion mode (namely the driving mode), and the frequency of the in-phase motion mode can be designed to be far higher than that of the anti-phase differential motion mode through the design of the diamond coupling structure, so that the interference mode during the operation of the gyroscope is reduced, and the modal coupling error is reduced.
In order to further explain the invention, the working mode of the scheme of the application is further explained by combining the attached drawings.
1. Driving mode:
the driving masses 11 are pushed by the horizontal electrostatic force generated by the comb structures in the driving structure to reciprocate in the horizontal direction (i.e. the planar direction of the in-plane sensitive axis micromechanical gyroscope), and at this time, the four driving masses 11 in the gyroscope of the present invention perform back and forth tangential motion in the horizontal direction, as shown in fig. 3.
2. Detecting a mode:
when angular velocity is input in the in-plane sensitive axis direction (the thickness direction of the gyroscope structure is called as an out-of-plane direction, the length and width directions are called as in-plane directions, and the two directions parallel to the plane of the gyroscope are referred to herein) of the in-plane sensitive axis micromechanical gyroscope, a coriolis force in the normal direction is generated on the driving mass block 11, so that the lever-type decoupling structure 13 drives the detection mass block to realize torsional motion in the normal direction. The detection electrode is arranged below the detection mass block (and on one side of the detection mass block), so that the change of displacement can be sensed, and the input of the external angular velocity can be demodulated. The detection mode of the gyroscope is shown in fig. 4.
In the present embodiment, a torsional motion is detected. As can be seen from fig. 3, in the driving mode of the in-plane sensitive axis micromechanical gyroscope according to the present invention, the horizontal motion of the driving mass 11 does not drive the proof mass 12, and only the normal motion of the driving mass 11 under the action of the coriolis force drives the proof mass 12, so that mode decoupling is achieved.
Through the arrangement, the decoupling structure 13 not only realizes decoupling of the driving mode and the detection mode of the in-plane gyroscope, but also improves the signal-to-noise ratio of the in-plane sensitive axis micro-mechanical gyroscope through the amplification effect of the lever.
Through the arrangement, the integral structure of the invention is composed of a plurality of symmetrical lever-type decoupling units, and the lever-type decoupling units are connected through the coupling units to realize differential motion, thereby effectively eliminating the influence of external environment and improving the stability.
Through the arrangement, the lever-type decoupling structure 13 adopts the multi-beam levers with different bending rigidities (realized by changing the beam width, the section shape and the like) in the design of the driving lever part and the detection lever part, so that the bending rigidity of the driving lever part in the horizontal direction is reduced, and the bending rigidity in the normal direction is increased. Meanwhile, through the isolation effect of the lever fulcrum beam supported by the anchor point, the horizontal displacement of the detection lever part caused by the horizontal bending of the driving lever part is greatly reduced, and thus the modal decoupling is more effectively realized.
Through the arrangement, the decoupling structure 13 has higher normal bending rigidity of the driving lever part and the detection lever part, so that the normal direction displacement of the driving mass block can be transmitted to the detection mass block, and the detection of the angular velocity is effectively realized.
Through the arrangement, the lever has the displacement amplification effect, so that the decoupling structure 13 can realize amplification of detection displacement by reasonably designing the proportion of the moment arm of the driving lever part and the moment arm of the detection lever part, and the normal displacement of the detection mass block is improved, so that the signal-to-noise ratio of the decoupling structure is improved.
Through the arrangement, the in-plane sensitive axis micro mechanical gyroscope has the advantages of large detection capacitance, high sensitivity and convenience in processing based on the principles of comb electrostatic driving and flat capacitance detection. In addition, four symmetrical large-area sensitive mass blocks (four driving mass blocks and four detection mass blocks) are adopted, differential detection can be formed, the same external interference is given to the differential, and the advantages of high sensitivity and strong anti-interference capability are further guaranteed. In addition, the structure has the advantages of decoupling of a driving mode and a detection mode, and can effectively inhibit mode coupling errors caused by machining errors, so that the stability of the gyroscope is improved.
Through the arrangement, the special decoupling structure can realize the modal decoupling of the MEMS in-plane gyroscope. By designing the horizontal bending rigidity and the normal bending rigidity of the multi-beam, the decoupling in the horizontal direction and the coupling in the normal direction are realized.
The foregoing is merely exemplary of particular aspects of the present invention and devices and structures not specifically described herein are understood to be those of ordinary skill in the art and are intended to be implemented in such conventional ways.
The above description is only one embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.