CN112833869A

CN112833869A - Decoupling type double-mass silicon micromechanical vibration gyroscope structure

Info

Publication number: CN112833869A
Application number: CN202110014421.XA
Authority: CN
Inventors: 裘安萍; 施芹; 赵阳; 夏国明
Original assignee: Nanjing University of Science and Technology
Current assignee: Nanjing University of Science and Technology
Priority date: 2021-01-06
Filing date: 2021-01-06
Publication date: 2021-05-25
Anticipated expiration: 2041-01-06
Also published as: CN112833869B

Abstract

The invention discloses a decoupling type double-mass silicon micromechanical vibration gyroscope structure, which is used for measuring an angular rate measuring instrument vertical to the horizontal direction of a base and comprises upper-layer monocrystalline silicon, middle-layer monocrystalline silicon and lower-layer monocrystalline silicon, wherein the upper-layer monocrystalline silicon is a silicon micro-gyroscope packaging cover plate provided with a lead for signal input/output, a gyroscope mechanical structure is manufactured on the middle-layer monocrystalline silicon, the lower-layer monocrystalline silicon is a gyroscope substrate provided with a fixed base, and the middle-layer monocrystalline silicon is sealed in a closed cavity formed by the upper-layer monocrystalline silicon and the lower-layer monocrystalline silicon. The invention has small mechanical coupling error, high mechanical sensitivity, low vibration sensitivity and low temperature sensitivity, and can realize motion decoupling, large amplitude vibration and detection output decoupling of the driving structure and the detection structure.

Description

Decoupling type double-mass silicon micromechanical vibration gyroscope structure

Technical Field

The invention belongs to micro-electromechanical systems and micro-inertia measurement technologies, and particularly relates to a decoupling type double-mass silicon micro-mechanical vibration gyroscope structure.

Background

The silicon micromechanical gyroscope is an inertial sensor for measuring the rotation angular rate, adopts the micromechanical processing technology to realize structural processing, and can be completely integrated with a measurement and control circuit thereof on a silicon chip, so that the silicon micromechanical gyroscope has the advantages of small volume, low cost, light weight, high reliability and the like, and has important application value in the dual-purpose field of military and civil.

At present, the performance of the silicon micromechanical gyroscope in the laboratory environment in China has been developed from the level of a common automobile to the level close to the tactical level (1 degree/h). Two key problems to be solved by the silicon micromechanical gyroscope from a laboratory to a practical application occasion are vibration environment adaptability and temperature environment adaptability. When the vibration magnitude of the silicon micromechanical vibration gyroscope (201511004405.3) with an I-shaped structure developed by Nanjing university of Physician is 7.0grms, the vibration variation is less than 10 degrees/h, the zero offset stability in the full temperature range is close to 10 degrees/h, and the silicon micromechanical vibration gyroscope has engineering application capability. In the research, the mechanical coupling error of the silicon micro mechanical gyroscope is found to be larger, and about 40.3 percent of the structural chips with the orthogonal coupling error of less than 300 DEG/s and the in-phase coupling error of less than 10 DEG/s exist in the current technology level. The mechanical coupling error has a great influence on the performance of the silicon micromechanical vibration gyro, wherein the orthogonal coupling error limits the measuring range of the silicon micromechanical vibration gyro, and the in-phase coupling error influences the temperature characteristic. The mechanical coupling error mainly comes from a driving structure, and for this reason, a decoupling type dual-mass gyro structure (gyro with structure for use of anti-phase drive and linear coupled anti-phase sense-mode, Transducers 2009) is proposed in 2009 by the university of california at usa. Based on the idea of decoupling the movement of a driving structure and a detection structure of a gyroscope structure, the university of southeast (201410449942.8, 201410362573.9, 20140164249.6 and 201510479060.0), the university of Nanjing Physician (201610878919.X) and other units propose a decoupling type double-mass silicon micromechanical gyroscope. In fact, compared with the traditional manufacturing process, the relative error of the MEMS process is about 2-3 orders of magnitude, the processing error causes structural asymmetry, and a larger coupling effect still exists between the driving structure and the detection structure of the decoupling type dual-mass gyroscope. Particularly, when the driving structures are distributed, firstly, the comb gap error generated by etching is large, and then large non-ideal force is generated on the driving comb, and large orthogonal coupling error and in-phase coupling error are generated; secondly, the deformation of the driving comb fixing electrode generated during the temperature change is large, the temperature coefficients of the orthogonal coupling error and the in-phase coupling error are large, and the temperature performance of the gyroscope is poor.

Disclosure of Invention

The invention aims to provide a silicon micromechanical gyroscope with small mechanical coupling error, high mechanical sensitivity, low vibration sensitivity and low temperature sensitivity, which can realize motion decoupling and large-amplitude vibration of a driving structure and a detection structure.

The technical solution for realizing the purpose of the invention is as follows:

a decoupling type double-mass silicon micromechanical vibrating gyroscope is composed of an upper layer of monocrystalline silicon, a middle layer of monocrystalline silicon and a lower layer of monocrystalline silicon, wherein the upper layer of monocrystalline silicon is a silicon micro-gyroscope packaging cover plate which is provided with a lead, a getter and a fixed base for signal input/output, a gyroscope mechanical structure is manufactured on the middle layer of monocrystalline silicon, the lower layer of monocrystalline silicon is a gyroscope substrate which is provided with the fixed base, and the middle layer of monocrystalline silicon is sealed in a closed cavity formed by the upper layer of monocrystalline silicon and the lower layer of monocrystalline silicon; the mechanical structure of the middle-layer monocrystalline silicon is characterized by comprising two first and second fully symmetrical sub-structures, a first cross beam and a second cross beam which are respectively positioned on two sides of the two sub-structures, and a first torsion bar, a second torsion bar and a driving coupling beam which are positioned between the two sub-structures; the first substructure and the second substructure are decoupling type single mass angular rate detection units, the first driving structure of the first substructure and the second driving structure of the second substructure are of an integral frame type structure, and the first driving structure and the second driving structure are respectively positioned at the central positions of the first substructure and the second substructure; the first driving structure and the second driving structure form coupling through the driving coupling beam and move oppositely along the driving shaft under the action of electrostatic force; the first and second sub-structures are symmetrically arranged about the detection axis and are connected with the first and second fixed bases through the first and second cross beams, the first and second torsion bars; the first and second fixed bases are respectively connected with the fixed bases of the upper layer monocrystalline silicon and the lower layer monocrystalline silicon, so that the mechanical structure of the middle layer monocrystalline silicon is suspended between the upper layer monocrystalline silicon and the lower layer monocrystalline silicon.

Compared with the prior art, the invention has the following remarkable advantages:

(1) the driving structure of the substructure is an integral frame structure and is positioned in the middle of the substructure, and the driving comb teeth are arranged in a concentrated manner, so that the tooth gap asymmetry caused by process errors and the base displacement change caused by temperature change are reduced, the in-phase coupling error and the orthogonal coupling error are reduced, the temperature coefficients of the in-phase coupling error and the orthogonal coupling error are reduced, and the performance of the gyroscope in a temperature environment is improved; (2) the driving frames of the two substructures are connected through the middle driving coupling beam, so that the consistency of driving motion of the two substructures is ensured, and a driving mode and an x-direction in-phase mode are well isolated; (3) the driving structures and the mass blocks of the two substructures are connected with the detection structure through reasonable supporting beams, so that the decoupling of the movement of the driving structures and the movement of the detection structure is realized, and the movement coupling of the driving structures to the detection structure under the non-ideal condition is greatly reduced; (4) the detection comb teeth of the single substructure are symmetrical about the driving shaft (x axis), the two substructures are fully symmetrical about the detection shaft (y axis), and the detection comb tooth capacitor greatly reduces the influence of process errors on output through twice difference.

Drawings

Fig. 1 is a schematic structural cross-sectional view of a decoupling type double-mass silicon micromechanical vibration gyroscope according to the present invention.

Fig. 2 is a schematic structural diagram of a decoupling type double-mass silicon micromechanical vibration gyroscope according to the present invention.

Fig. 3 is a schematic diagram of a driving structure of a silicon micromachined gyroscope of the present invention.

Fig. 4 is a schematic diagram of a variable pitch detection structure of a silicon micromechanical gyroscope according to the present invention.

Fig. 5 is a schematic diagram of a variable-area detection structure of the silicon micromechanical gyroscope of the present invention.

Fig. 6 is a schematic diagram of a comb structure of the open-loop detection scheme of the silicon micromechanical gyroscope according to the present invention.

Fig. 7 is a schematic diagram of a comb structure of a closed-loop detection scheme of the silicon micromechanical gyroscope according to the present invention.

Detailed Description

The invention is further described with reference to the following figures and embodiments.

The invention relates to a decoupling type double-mass silicon micromechanical vibration gyroscope structure, which is used for measuring an angular rate measuring instrument vertical to a base level and comprises an upper layer monocrystalline silicon 51, a middle layer monocrystalline silicon 52 and a lower layer monocrystalline silicon 53, wherein the upper layer monocrystalline silicon 51 is a silicon micro gyroscope packaging cover plate provided with a lead 54 for signal input/output, a getter 55 and a fixed base 56, a gyroscope mechanical structure is manufactured on the middle layer monocrystalline silicon 52, the lower layer monocrystalline silicon 53 is a gyroscope substrate provided with a fixed base 57, and the middle layer monocrystalline silicon 52 is sealed in a closed cavity formed by the upper layer monocrystalline silicon 51 and the lower layer monocrystalline silicon 53. The mechanical structure of the middle layer monocrystalline silicon 52 comprises two fully symmetrical substructures, a cross beam, a coupling beam and a torsion bar, wherein the two substructures are symmetrically arranged about a detection axis (y axis) and are connected with the fixed base through the cross beam and the torsion bar; the substructure is a decoupling type single mass angular rate detection unit, wherein the driving structure is an integral frame structure and is positioned at the center of the substructure. All the fixed bases are connected with the fixed bases of the upper layer monocrystalline silicon and the lower layer monocrystalline silicon, so that the mechanical structure of the middle layer monocrystalline silicon is suspended between the upper layer monocrystalline silicon and the lower layer monocrystalline silicon.

With reference to fig. 2, the gyroscope mechanical structure on the middle layer monocrystalline silicon wafer of the decoupling type dual-mass silicon micromechanical vibrating gyroscope structure of the present invention is composed of a first substructure 100, a second substructure 200, a first beam 2a, a second beam 2b, a first torsion bar 3a, a second torsion bar 3b, and a driving coupling beam 5, wherein the first substructure 100 and the second substructure 200 are completely the same in composition and structure and are symmetrically arranged about a detection axis (y axis); the first driving structure 150 of the first substructure 100 is connected with the second driving structure 250 of the second substructure 200 by the driving coupling beam 5; the upper end of the first substructure 100 and the upper end of the second substructure are connected to the two ends of the first beam 2a, and then connected to the first fixed base 4a by the first torsion bar 3 a; the lower end of the first substructure 100 and the lower end of the second substructure are connected with two ends of a second beam 2b, and then connected with a second fixed base 4b through a second torsion bar 3b, and the first fixed base 4a and the second fixed base 4b are bonded with the corresponding fixed bases on the upper layer monocrystalline silicon and the lower layer monocrystalline silicon.

The first substructure 100 of the decoupled dual-mass silicon micromachined vibratory gyroscope structure of the present invention includes a first driving structure 150, first, second, third, and fourth

detection isolation beams

105a, 105b, 105c, 105d, a first frame-type mass 106, first, second, third, and fourth

driving isolation beams

107a, 107b, 107c, 107d, first and

second detection structures

160a, 160b, first, second, third, and fourth

detection support beams

109a, 109b, 109c, 109d, and third, fourth, and fifth fixed

bases

4c, 4d, 4 e. The first driving structure 150 is located in the middle of the first substructure 100, and the third fixed base 4c is located in the middle of the first driving structure 150; the fourth and fifth fixed

bases

4d and 4e are symmetrically arranged on both sides of the first driving structure 150 with respect to the driving shaft; the first, second, third, and fourth

detection isolation beams

105a, 105b, and 105c and the first, second, third, and fourth

detection support beams

109a, 109b, 109c, and 109d are respectively centrosymmetric with respect to the third fixed base 4 c.

And the third, fourth and fifth fixed

bases

4c, 4d and 4e are bonded with the corresponding fixed bases on the upper layer of monocrystalline silicon and the lower layer of monocrystalline silicon. The first driving structure 150 is located in the middle of the first substructure 100, and two sides of the upper and lower ends of the first driving structure 150 are respectively connected with the first frame-type mass block 106 through the first and second

detection isolation beams

105a and 105b and the third and fourth

detection isolation beams

105c and 105 d; the first detection structure 160a and the second detection structure 160b are symmetrically arranged on two sides of the first frame-type mass block 106 about the driving shaft (x axis), two sides of the upper end of the first frame-type mass block 106 are connected with the first detection structure 160a through the first and second

driving isolation beams

107a and 107b, and two sides of the lower end of the first frame-type mass block 106 are connected with the second detection structure 160b through the third and fourth

driving isolation beams

107c and 107 d; two sides of the lower end of the first detection structure 160a are respectively connected with the

fixed bases

4d and 4a through the first detection supporting beam 109a and the second detection supporting beam 109b, and the

fixed bases

4a and 4d are bonded with the corresponding fixed bases on the upper layer of monocrystalline silicon and the lower layer of monocrystalline silicon; both sides of the upper end of the second detecting structure 160b are connected to the

fixed bases

4b and 4e through the third detecting support beam 109c and the fourth detecting support beam 109d, respectively.

The second substructure 200 includes a second driving structure 250, fifth, sixth, seventh, eight

detection isolation beams

205a, 205b, 205c, 205d, a second frame-type mass 206, fifth, sixth, seventh, eight

driving isolation beams

207a, 207b, 207c, 207d, first and

second detection structures

160a, 160b, fifth, sixth, seventh, eight

detection support beams

209a, 209b, 209c, 209d, and sixth, seventh, eight

fixed bases

4f, 4g, 4 h. The second driving structure 250 is located in the middle of the second substructure 200, and the sixth fixed base 4f is located in the middle of the second driving structure 250; the seventh and eighth fixed

bases

4g and 4h are symmetrically arranged on both sides of the second driving structure 250 with respect to the driving shaft; the fifth, sixth, seventh, and eighth

detection partition beams

205a, 205b, and 205c, and the fifth, sixth, seventh, and eighth

detection support beams

209a, 209b, 209c, and 209d are respectively centrosymmetric with respect to the sixth fixed base 4 f.

And the sixth, seventh and eighth fixed

bases

4f, 4g and 4h are bonded with the corresponding fixed bases on the upper and lower layers of monocrystalline silicon. The second driving structure 250 is located in the middle of the second substructure 200, and the upper and lower ends of the second driving structure 250 are connected to the second frame-type proof mass 206 through the fifth and sixth

detection isolation beams

205a and 205b and the seventh and eighth

detection isolation beams

205c and 205d, respectively; the third detection structure 260a and the fourth detection structure 260b are symmetrically arranged on two sides of the second frame-type mass 206 with respect to the driving axis (x-axis), two sides of the upper end of the second frame-type mass 206 are connected to the third detection structure 260a through the fifth and sixth driving isolation beams 207a and 207b, and two sides of the lower end of the second frame-type mass 206 are connected to the fourth detection structure 260b through the seventh and eighth

driving isolation beams

207c and 207 d; the third detecting structure 260a is connected to the

fixed bases

4a and 4g through the fifth detecting support beam 209a and the sixth detecting support beam 209b on both sides of the lower end thereof, and the second detecting structure 260b is connected to the

fixed bases

4b and 4h through the seventh detecting support beam 209c and the eighth detecting support beam 209d on both sides of the upper end thereof.

Referring to fig. 2 and 3, the first driving structure 150a includes a first driving frame 101, first and second

driving support beams

102a and 102b, first and second driving comb-teeth fixed

electrodes

103a and 103b, and first and second driving detection comb-teeth fixed

electrodes

104a and 104 b. The first driving frame 101 is provided with movable comb teeth, and part of the movable comb teeth and fixed comb teeth on the first driving comb tooth fixed electrode 103a and the second driving comb tooth fixed electrode 103b form a driving comb tooth capacitor; part of the movable comb teeth and the fixed comb teeth on the first drive detection comb fixed electrode 104a and the second drive detection comb fixed electrode 104b form a drive detection comb capacitor; the first drive comb-tooth fixed electrode 103a, the second drive comb-tooth fixed electrode 103b, the first drive detection comb-tooth fixed electrode 104a, and the second drive detection comb-tooth fixed electrode 104b are arranged side by side, wherein the first drive comb-tooth fixed electrode 103a and the second drive comb-tooth fixed electrode 103b are located between the four fixed electrodes; applying an alternating current voltage with direct current bias to the first driving comb-tooth fixed electrode 103a, and applying an opposite alternating current voltage with direct current bias to the second driving comb-tooth fixed electrode 103b to form bilateral driving; the first drive detection comb-tooth fixed electrode 104a and the second drive detection comb-tooth fixed electrode 104b are applied with reverse-phase dc voltages, respectively, to form differential capacitance detection.

The detection structure of the decoupling type double-mass silicon micromechanical vibration gyroscope structure can adopt two schemes of variable-pitch detection and variable-area detection of comb capacitors, and FIG. 4 is a variable-pitch detection scheme of the gyroscope detection structure. With reference to fig. 2 and 4, the first detecting structure 160a and the second detecting structure 160b have the same composition and structure, and are symmetrically disposed on the upper and lower sides of the first sub-structure 100. The first detecting structure 160a includes a first detecting frame 108a, first and second detecting comb-tooth fixed

electrodes

110a, 110b, a first detecting movable comb-tooth 161a and a first detecting fixed comb-tooth 162 a; the first detection movable comb tooth 161a is disposed on the first detection frame 108a, and the first detection fixed comb tooth 162a is disposed on the first and second detection comb-tooth fixed

electrodes

110a, 110 b. The first movable detection comb 161a and the first fixed detection comb 162a constitute a detection comb capacitor, and the first detection structure 160a and the detection comb capacitor of the second detection structure 160b constitute differential detection.

FIG. 5 shows a top detection structure with a variable area detection scheme, wherein the first detection structure 160a comprises a first detection frame 108a, first and second detection comb-

fixed electrodes

110a and 110b, a detection movable comb arm 163, a detection movable comb 164, a detection fixed comb arm 165 and a detection fixed comb 166; the first detection frame is provided with a detection movable comb tooth arm 163, the detection movable comb tooth arm 163 is provided with a detection movable comb tooth 164, the first detection comb tooth fixed electrode 110a is provided with a detection fixed comb tooth arm 165, the detection fixed comb tooth arm 165 is provided with a detection fixed comb tooth 166, and the detection movable comb tooth 164 and the detection fixed comb tooth 166 form a detection comb tooth capacitor.

The decoupling type double-mass silicon micromechanical vibration gyroscope structure can adopt two schemes of open loop and closed loop, and is explained by using a variable-interval detection structure of a comb capacitor. FIG. 6 is a schematic diagram of the detection comb structure for open-loop detection of the gyroscope, the detection comb structure for open-loop detection of the gyroscope is composed of first, second, third and fourth detection comb-

fixed electrodes

110a, 110b, 110c, 110d, fifth, sixth, seventh and eighth detection comb-

fixed electrodes

210a, 210b, 210c, 210d, first, second, third and fourth

fixed detection combs

162a, 162b, 262a and 262b, and first, second, third and fourth

movable detection combs

161a, 161b, 261a and 261b respectively disposed on the first, second, third and

fourth detection frames

108a, 108b, 208a and 208b, the first, second, third, fourth, fifth, sixth, seventh and eighth detection comb-

fixed electrodes

110a, 110b, 110c, 110d, 210a, 210b, 210c and 210d respectively disposed on the first, second, third, fourth

fixed detection combs

162a, 162b, 262a and 262b, and the first, second, third, fourth

fixed detection combs

162a, 162b, 262a and 262b respectively disposed on the first, second, third, fourth detection comb-fixed, The first, second, third and fourth movement

detection comb teeth

161a, 161b, 261a and 261b on the second, third and

fourth detection frames

108a, 108b, 208a and 208b are oppositely inserted to form eight groups of detection comb tooth capacitors; the first fixed detection comb teeth 162a and the first movable detection comb teeth 161a on the first and second detection comb-tooth fixed

electrodes

110a and 110b form first and second detection capacitors D1 and D2, the second fixed detection comb teeth 162b and the second movable detection comb teeth 161b on the third and fourth detection comb-tooth fixed electrodes 110c and 110D form third and fourth detection capacitors D3 and D4, and the first and second detection capacitors D1 and D2 and the third and fourth detection capacitors D3 and D4 are symmetrically arranged to form differential detection for detecting the movement displacement of the first and

second detection frames

108a and 108b of the first substructure 100 in the y-axis direction; the third fixed detection comb teeth 262a and the third movable detection comb teeth 261a on the fifth and sixth detection comb tooth fixed

electrodes

210a and 210b form fifth and sixth detection capacitors D5 and D6, the fourth fixed detection comb teeth 262b and the fourth movable detection comb teeth 261b on the seventh and eighth detection comb tooth fixed electrodes 210c and 210D form second detection capacitors D7 and D8, and the fifth and sixth detection capacitors D5 and D6 and the seventh and eighth detection capacitors D7 and D8 are symmetrically arranged to form differential detection for detecting the movement displacement of the third and

fourth detection frames

208a and 208b of the second substructure 200 in the y-axis direction; the first detection capacitors D1 and D2 are the same as the comb tooth arrangements of the fifth detection capacitors D5 and D6, the third detection capacitors D3 and D4 are the same as the comb tooth arrangements of the seventh detection capacitors D7 and D8, the substructure 100 moves opposite to the substructure 200, the first detection capacitors D1 and D2 and the fifth detection capacitors D5 and D6 form differential detection, the third detection capacitors D3 and D4 and the seventh detection capacitors D7 and D8 form differential detection, and the influence of processing error and equidirectional motion on output is greatly inhibited by the two differential detections.

The detection comb structure of closed-loop detection is shown in fig. 7. First, second, third, fourth detection comb-tooth fixed

electrodes

110a, 110b, 110c, 110d, fifth, sixth, seventh, eighth detection comb-tooth fixed

electrodes

210a, 210b, 210c, 210d, first, second, third, fourth force-application comb-tooth fixed

electrodes

111a, 111b, 111c, 111d, fifth, sixth, seventh, eighth force-application comb-tooth

fixed electrodes

211a, 211b, 211c, 211d, first, second, third, fourth fixed detection comb-

teeth

162a, 162b, 262a, 262b, and first, second, third, fourth movable detection comb-

teeth

161a, 161b, 261a, 261b respectively disposed on first, second, third,

fourth detection frames

108a, 108b, 208a, 208b constitute a detection comb-tooth structure for closed-loop detection, the first fixed detection comb-teeth 162a are also disposed on the first, second, third, fourth force-application comb-tooth fixed

electrodes

111a, 162b, and the third, fourth force-application comb-tooth fixed electrodes 11c, 111d are also provided with second fixed detection comb teeth 162b, fifth and sixth forcing comb-tooth fixed electrodes 211a, 211b are also provided with third fixed detection comb teeth 262a, and seventh and eighth forcing comb-tooth fixed

electrodes

211c, 211d are also provided with second fixed detection comb teeth 262 b. The first, second, third, fourth, fifth, sixth, seventh, eighth detection comb-tooth fixed

electrodes

110a, 110b, 110c, 110d, 210a, 210b, 210c, 210d and the first, second, third, fourth, fifth, sixth, seventh, eighth forcing comb-tooth fixed

electrodes

111a, 111b, 111c, 111d, 211a, 211b, 211c, 211d are oppositely inserted with the first, second, third, and fourth fixed detection comb-

teeth

162a, 162b, 262a, 262b arranged on the first, second, third, and

fourth detection frames

108a, 108b, 208a, 208b to form eight groups of detection comb-tooth capacitors and eight groups of forcing capacitors; the first fixed detection comb teeth 162a and the first movable detection comb teeth 161a on the first and second detection comb tooth

fixed electrodes

110a and 110b form first and second detection capacitors D1 and D2, the second fixed detection comb teeth 162b and the second movable detection comb teeth 161b on the third and fourth detection comb tooth fixed electrodes 110c and 110D form third and fourth detection capacitors D3 and D4, and the first and second detection capacitors D1 and D2 and the third and fourth detection capacitors D3 and D4 are symmetrically arranged to form differential detection for detecting the movement displacement of the first and

second detection frames

electrodes

fourth detection frames

208a and 208b of the second substructure 200 in the y-axis direction; the first detection capacitor D1 and the second detection capacitor D2 are the same as the comb tooth arrangement of the fifth detection capacitor D5 and the sixth detection capacitor D6, the third detection capacitor D3 and the fourth detection capacitor D4 are the same as the comb tooth arrangement of the seventh detection capacitor D7 and the eighth detection capacitor D8, because the substructure 100 moves opposite to the substructure 200, the first detection capacitor D1 and the second detection capacitor D2 and the fifth detection capacitor D5 and the sixth detection capacitor D6 form differential detection, the third detection capacitor D3 and the fourth detection capacitor D4 and the seventh detection capacitor D7 and the eighth detection capacitor D8 form differential detection, and the influence of processing errors and the same-direction movement on output is greatly inhibited by the two-time differential detection. The first fixed detection comb teeth 162a on the first and second force application comb-tooth fixed electrodes 111a and 111b and the first movable detection comb teeth 161a on the first detection frame form first and second force application capacitors A1 and A2, the second fixed detection comb teeth 162b on the third and fourth force application comb-tooth fixed

electrodes

111c and 111d and the second movable detection comb teeth 161b on the second detection frame form third and fourth force application capacitors A3 and A4, the third fixed detection comb teeth 262a on the fifth and sixth force application comb-tooth fixed electrodes 211a and 211b and the third movable detection comb teeth 261a on the third detection frame form fifth and sixth force application capacitors A5 and A6, and the fourth fixed detection comb teeth 262b on the seventh and eighth force application comb-tooth fixed

electrodes

211c and 211d and the fourth movable detection comb teeth 261b on the fourth detection frame form seventh, eighth force application capacitors A7 and A8. Voltages are applied to the force application comb-tooth fixed

electrodes

111a, 111b, 211a, and 211b, and electrostatic forces are generated. The detection capacitors D1-D8 and the force application capacitors A1-A8 form a closed loop detection, and the first, second, third and

fourth detection structures

108a, 108b, 208a and 208b and the first and second frame-type masses 106 and 206 are controlled to be in equilibrium positions.

Applying a dc-biased ac voltage (input through the input line of the upper layer of monocrystalline silicon) to the first drive comb-tooth fixed electrode 103a of the first drive structure 150 and the fourth drive comb-tooth fixed electrode 203b of the second drive structure 250, applying a dc-biased inverted ac voltage (input through the input line of the upper layer of monocrystalline silicon) to the second drive comb-tooth fixed electrode 103b and the third drive comb-tooth fixed electrode 203a, and generating alternating electrostatic drive forces with equal amplitude and 180 degrees difference on the first drive structure 150 and the second drive structure 250, respectively, the electrostatic drive forces having amplitudes:

wherein n is the number of teeth of the driving movable comb of the first substructure 100 or the second substructure 200, ε is the dielectric constant, h is the thickness of the gyroscope structure, d is the comb tooth spacing, U_dDC bias voltage for the drive voltage, U_aIs an alternating voltage, omega_dIs the angular frequency of the ac voltage. Therefore, the first driving structure 150 together with the first frame mass 106 and the second driving structure 250 together with the second frame mass 206 vibrate along the driving axis (x-axis) at opposite simple harmonic lines under the electrostatic driving force.

The drive detection comb-tooth capacitor formed by the movable comb-tooth on the first drive frame 101 and the fixed comb-teeth on the first and second drive detection comb-tooth fixed

electrodes

104a and 104b, and the drive detection comb-tooth capacitor formed by the movable comb-tooth on the second drive frame 201 and the fixed comb-tooth on the third and fourth drive detection comb-tooth fixed

electrodes

204a and 204b are used for detecting drive vibration and feeding back the drive vibration to the drive comb-tooth capacitor to make adjustment, thereby realizing closed-loop drive.

When the driving mode is in resonance, the linear vibration displacement is:

in the formula, k_xFor elastic stiffness of the gyro drive shaft (x-axis), Q_xT is the time, which is the quality factor of the driving mode. The linear vibration speed was:

when the gyroscope has an external input angular rate omega about the z-axis_zAccording to the right-hand rule, the gyro detection axis (Y axis) is subject to the action of coriolis acceleration, and its magnitude is:

in the formula (I), the compound is shown in the specification,

is the right-hand included angle between the input angular rate and the linear vibration speed.

The first and second frame-type masses 106 and 206 have a mass m_sThe coriolis force acting on the sensing structure is then:

the direction of the coriolis force is opposite to the direction of the coriolis acceleration, and therefore, the coriolis force acting on the first and second frame masses 106, 206 is opposite. Under the action of the coriolis force, the first frame-type mass 106, together with the first and

second detection frames

108a and 108b, and the second frame-type mass 206, together with the third and

fourth detection frames

208a and 208b, vibrate along the detection axis (y-axis) at opposite simple harmonic lines. Therefore, the gap between the movable detection comb teeth and the fixed detection comb teeth is changed according to a certain simple harmonic vibration rule, and the capacitance difference signal is processed by an electronic circuit through the output line of the upper monocrystalline silicon to obtain an output voltage signal. The output voltage signal is the sum of the output voltage signals of the first and

second substructures

100 and 200, and the magnitude of the output voltage signal is proportional to the magnitude of the input angular rate. The phase relationship between the output voltage signal and the excitation signal is compared by the phase discriminator, so that the direction of the input angular rate can be judged.

The drive structure of the decoupling type double-mass silicon micromechanical vibration gyroscope structure is an integral frame structure and is positioned in the middle of the substructure, so that the influence of process errors on the performance of the gyroscope is reduced. The decoupling type double-mass silicon micromechanical vibration gyroscope structure and the decoupling type double-mass silicon micromechanical vibration structure with the driving structure distributed are prepared by the same SOI process, and wafer test data statistics results show that the structure chip with the orthogonal coupling error smaller than 100 degrees/s and the in-phase coupling error smaller than 1 degree/s of the gyroscope structure is 62.6 percent. And the structure chip with the driving structure distributed with the gyro has quadrature coupling error less than 300 deg/s and in-phase coupling error less than 5 deg/s in 44.8%. Therefore, the invention effect of the invention patent is obvious.

Claims

1. A decoupling type double-mass silicon micromechanical vibration gyroscope structure is composed of an upper layer monocrystalline silicon (51), a middle layer monocrystalline silicon (52) and a lower layer monocrystalline silicon (53), wherein the upper layer monocrystalline silicon (51) is a silicon micro gyroscope packaging cover plate which is provided with a lead (54) for signal input/output, a getter (55) and a fixed base (56), a gyroscope mechanical structure is manufactured on the middle layer monocrystalline silicon (52), the lower layer monocrystalline silicon (53) is a gyroscope substrate provided with a fixed base (57), and the middle layer monocrystalline silicon (52) is sealed in a sealed cavity formed by the upper layer monocrystalline silicon (51) and the lower layer monocrystalline silicon (53); the middle-layer monocrystalline silicon (52) is characterized in that the mechanical structure comprises two fully symmetrical first substructures (100), a second substructure (200), a first cross beam (2a) and a second cross beam (2b) which are respectively positioned at two sides of the two substructures, and a first torsion bar (3a), a second torsion bar (3b) and a driving coupling beam (5) which are positioned between the two substructures; the first substructure (100) and the second substructure (200) are decoupling type single mass angular rate detection units, a first driving structure (150) of the first substructure (100) and a second driving structure (250) of the second substructure (200) are of an integral frame type structure, and the first driving structure (150) and the second driving structure (250) are respectively located at the central positions of the first substructure (100) and the second substructure (200); the first driving structure (150) and the second driving structure (250) form coupling through the driving coupling beam (5) and move oppositely along the driving shaft under the action of electrostatic force; the first and second substructures (100, 200) are symmetrically arranged about the detection axis and are connected with the first and second fixed bases (4a, 4b) through the first and second beams (2a, 2b) and the first and second torsion bars (3a, 3 b); the first and second fixed bases (4a, 4b) are connected to the fixed bases of the upper layer of monocrystalline silicon and the lower layer of monocrystalline silicon, respectively, so that the mechanical structure of the intermediate layer of monocrystalline silicon is suspended between the upper layer of monocrystalline silicon (51) and the lower layer of monocrystalline silicon (53).

2. A decoupled dual-mass silicon micromachined vibratory gyroscope structure of claim 1 wherein the first substructure (100) includes a first drive structure (150), first, second, third, and fourth sense isolation beams (105a, 105b, 105c, 105d), a first frame-type proof mass (106), first, second, third, and fourth drive isolation beams (107a, 107b, 107c, 107d), first and second sense structures (160a, 160b), first, second, third, and fourth sense support beams (109a, 109b, 109c, 109d), and third, fourth, and fifth fixed bases (4c, 4d, 4 e);

the third, fourth and fifth fixed bases (4c, 4d and 4e) are bonded with the corresponding fixed bases on the upper layer monocrystalline silicon and the lower layer monocrystalline silicon; the first driving structure (150) is positioned in the middle of the first substructure (100), and the third fixed base (4c) is positioned in the middle of the first driving structure (150); the fourth and fifth fixed bases (4d, 4e) are symmetrically arranged on both sides of the first driving structure (150) about the driving shaft; the first, second, third and fourth detection isolation beams (105a, 105b, 105c) and the first, second, third and fourth detection support beams (109a, 109b, 109c, 109d) are respectively in central symmetry with respect to the third fixed base (4 c);

two sides of two ends of the first driving structure (150) are respectively connected with the first frame-type mass block (106) through the first detection isolation beam (105 a), the second detection isolation beam (105 b), the third detection isolation beam (105 c), and the fourth detection isolation beam (105 d); the first detection structure (160a) and the second detection structure (160b) are symmetrically arranged on two sides of the first frame-type mass block (106) relative to the driving shaft, two sides of one end of the first frame-type mass block (106) are connected with the first detection structure (160a) through the first driving isolation beams (107 a) and the second driving isolation beams (107 b), and two sides of the other end of the first frame-type mass block (106) are connected with the second detection structure (160b) through the third driving isolation beams and the fourth driving isolation beams (107c and 107 d); two sides of the other end of the first detection structure (160a) are respectively connected with a fourth fixed base (4d) and a first fixed base (4a) through a first detection supporting beam (109a) and a second detection supporting beam (109b), and the first fixed base (4a) and the fourth fixed base (4d) are bonded with the corresponding fixed bases on the upper layer of monocrystalline silicon and the lower layer of monocrystalline silicon; two sides of one end of the second detection structure (160b) are respectively connected with the second fixed base (4b) and the fifth fixed base (4e) through the third detection supporting beam (109c) and the fourth detection supporting beam (109d), and the second fixed base (4b) and the fifth fixed base (4e) are bonded with the corresponding fixed bases on the upper layer of monocrystalline silicon and the lower layer of monocrystalline silicon.

3. A decoupled dual mass silicon micromachined vibratory gyroscope structure of claim 2 wherein the first drive structure (150a) comprises a first drive frame (101), first and second drive support beams (102a, 102b), first and second drive comb fixed electrodes (103a, 103b), first and second drive sense comb fixed electrodes (104a, 104 b);

movable comb teeth are arranged on the first driving frame (101), and a part of the movable comb teeth, the first driving comb teeth fixed electrode (103a) and the fixed comb teeth on the second driving comb teeth fixed electrode (103b) form a driving comb teeth capacitor; part of movable comb teeth, the first drive detection comb tooth fixed electrode (104a) and the fixed comb teeth on the second drive detection comb tooth fixed electrode (104b) form a drive detection comb tooth capacitor; the first drive comb-tooth fixed electrode (103a), the second drive comb-tooth fixed electrode (103b), the first drive detection comb-tooth fixed electrode (104a), and the second drive detection comb-tooth fixed electrode (104b) are arranged side by side, wherein the first drive comb-tooth fixed electrode (103a) and the second drive comb-tooth fixed electrode (103b) are located between the four fixed electrodes.

4. The structure of a decoupled dual-mass silicon micromachined vibratory gyroscope of claim 3 wherein a DC-biased AC voltage is applied to the first drive comb fixed electrode (103a) and a DC-biased opposing AC voltage is applied to the second drive comb fixed electrode (103b) to form a dual-sided drive; the first drive detection comb-tooth fixed electrode (104a) and the second drive detection comb-tooth fixed electrode (104b) are applied with reverse-phase DC voltage to form differential capacitance detection.

5. The decoupled dual mass silicon micromachined vibratory gyroscope structure of claim 2, employing variable pitch detection of comb capacitors: the first detection structure (160a) comprises a first detection frame (108a), first and second detection comb-tooth fixed electrodes (110a, 110b), a first detection movable comb-tooth (161a) and a first detection fixed comb-tooth (162 a); a first detection movable comb (161a) is disposed on the first detection frame (108a), and a first detection fixed comb (162a) is disposed on the first and second detection comb fixed electrodes (110a, 110 b). The first detection movable comb teeth (161a) and the first detection fixed comb teeth (162a) form detection comb tooth capacitors, and the first detection structures (160a) and the detection comb tooth capacitors of the second detection structures (160b) form differential detection.

6. The decoupled dual mass silicon micromachined vibratory gyroscope structure of claim 2, employing variable area detection: the first detection structure (160a) comprises a first detection frame (108a), first and second detection comb-tooth fixed electrodes (110a, 110b), a detection movable comb-tooth arm (163), a detection movable comb-tooth (164), a detection fixed comb-tooth arm (165) and a detection fixed comb-tooth (166); arrange on the first detection frame and detect activity broach arm (163), arrange on detecting activity broach arm (163) and detect activity broach (164), arrange on first detection broach fixed electrode (110a) and detect fixed broach arm (165), arrange on detecting fixed broach arm (165) and detect fixed broach (166), detect activity broach (164) and detect fixed broach (166) and constitute and detect broach capacitance.