High-integration micro-mechanical accelerometer-gyroscope

Abstract

The invention discloses a high-integration micro-mechanical accelerometer-gyroscope, and belongs to the technical field of inertial sensing. According to the invention, by sharing a mechanical structure and an electrode, applying a pair of direct-current voltage, resonance voltage and carrier voltage with opposite symbols on a symmetrical parallel-plate capacitor structure, and combining a PLL phase closed-loop control method, resonance driving, amplitude detection and frequency detection of a three-axis structure can be realized at the same time; force balance feedback voltage can be obtained through weighted fusion and controller calculation, the position of the mass block is kept constant, and at the moment, the feedback voltage reflects the acceleration; meanwhile, the three-axis resonant structure is subjected to the coriolis force coupling effect, the sum of the resonant frequencies of the two orthogonal axes comprises angular velocity information of the third orthogonal axis, and the angular velocity can be obtained through multiplication demodulation and low-pass filtering calculation with a sinusoidal signal with the frequency being the difference between the two frequencies. The micro-mechanical accelerometer-gyroscope integration method is simple, and temperature drift can be effectively inhibited at the same time.

Description

Technical Field

[0001] The present invention belongs to the technical field of inertial sensing, and more specifically, relates to a highly integrated micro-mechanical accelerometer-gyroscope. Background Art

[0002] Micromechanical accelerometers and gyroscopes are sensors for measuring acceleration and angular velocity, and are widely used in consumer electronics, automobiles, drones and other systems. The micro inertial measurement unit (MIMU) is composed of a 3-axis accelerometer and a 3-axis gyroscope, in which the two types of sensors usually adopt independent structures and are not highly integrated. A few micromechanical accelerometer-gyroscope integrated sensors also use different sensitive elements or detection modules to measure acceleration and angular velocity respectively. Although the acceleration detection module and the angular velocity detection module can be decoupled from each other, there is mutual interference due to the use of the same decoupling sensitive element or different detection methods. Summary of the invention

[0003] In view of the shortcomings and deficiencies of the existing micromechanical accelerometer-gyroscope integrated sensor, the present invention provides a highly integrated micromechanical accelerometer-gyroscope, which integrates an amplitude modulation / frequency modulation (AM / FM) composite accelerometer and a Lissajous frequency modulation (LFM) gyroscope, and adopts the same sensitive structure and resonant detection module to simultaneously realize XYZ three-axis acceleration and XYZ three-axis angular velocity detection. The present invention combines the AM / FM detection method to improve the sensor integration and reduce the mutual interference between acceleration and angular velocity detection.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0005] A highly integrated micromechanical accelerometer-gyroscope, using an XYZ three-degree-of-freedom mass-spring-damper system as a common sensitive structure, includes:

[0006] A mass block assembly, which is symmetrical about the Y axis, comprises an intermediate mass block, a torsion mass block located inside the intermediate mass block, and a pair of X-axis mass blocks and a pair of Y-axis mass blocks symmetrically distributed around the intermediate mass block about the center; the X-axis mass block and the Y-axis mass block are connected to the intermediate mass block through an X-axis decoupling spring and a Y-axis decoupling spring, respectively, and are connected to the anchor area through an X-axis mass block support spring and a Y-axis mass block support spring, respectively; the torsion mass block is connected to the intermediate mass block through a pair of Y-axis torsion elastic beams; the mass block assembly is located in the same XY plane;

[0007] An XYZ axisymmetric parallel plate capacitor, comprising a pair of first X axisymmetric parallel plate electrodes located in the negative direction of the X axis, a pair of second X axisymmetric parallel plate electrodes located in the positive direction of the X axis, a pair of first Y axisymmetric parallel plate electrodes located in the negative direction of the Y axis, a pair of second Y axisymmetric parallel plate electrodes located in the positive direction of the Y axis, and a pair of first Z axisymmetric parallel plate electrodes and a pair of second Z axisymmetric parallel plate electrodes located on the same side of the Z axis;

[0008] An XYZ axis driver comprises an XY axis variable area comb tooth driver and a Z axis variable pitch driver, wherein the XY axis variable area comb tooth driver comprises a first X axis variable area comb tooth electrode located in the negative direction of the X axis, a second X axis variable area comb tooth electrode located in the positive direction of the X axis, a first Y axis variable area comb tooth electrode located in the negative direction of the Y axis, and a second Y axis variable area comb tooth electrode located in the positive direction of the Y axis; and the Z axis variable pitch driver comprises a pair of first Z axis variable pitch driving electrodes and a pair of second Z axis variable pitch driving electrodes located on the same side of the Z axis.

[0009] As a preferred embodiment of the present invention, the first X-axis symmetric parallel plate electrode and the second X-axis symmetric parallel plate electrode are fixed in the anchor region and are symmetrically distributed about the Y axis;

[0010] The first X-axis variable-area comb-tooth electrode and the second X-axis variable-area comb-tooth electrode are fixed in the anchor region and are symmetrically distributed about the Y-axis;

[0011] The first X-axis symmetric parallel plate electrode and the movable parallel plate electrode installed on the left / right side of an X-axis mass block form a parallel plate capacitor, and the first X-axis variable area comb-tooth electrode and the movable comb teeth on the right / left side of the same X-axis mass block form a comb-tooth capacitor;

[0012] The second X-axis symmetric parallel plate electrode and the movable parallel plate electrode installed on the right / left side of another X-axis mass block form a parallel plate capacitor, and the second X-axis variable area comb electrode and the movable comb teeth on the left / right side of the same X-axis mass block form a comb capacitor.

[0013] As a preferred embodiment of the present invention, the first Y-axis symmetric parallel plate electrode and the second Y-axis symmetric parallel plate electrode are fixed in the anchor region and are symmetrically distributed about the X-axis;

[0014] The first Y-axis variable-area comb-tooth electrode and the second Y-axis variable-area comb-tooth electrode are fixed in the anchor region and are symmetrically distributed about the X-axis;

[0015] The first Y-axis symmetric parallel plate electrode and the movable parallel plate electrode installed on the lower side / upper side of a Y-axis mass block form a parallel plate capacitor, and the first Y-axis variable area comb-tooth electrode and the movable comb teeth on the upper side / lower side of the same Y-axis mass block form a comb-tooth capacitor;

[0016] The second Y-axis symmetric parallel plate electrode and the movable parallel plate electrode installed on the upper / lower side of another Y-axis mass block form a parallel plate capacitor, and the second Y-axis variable area comb electrode and the movable comb teeth on the lower / upper side of the same Y-axis mass block form a comb capacitor.

[0017] As a preferred embodiment of the present invention, the pair of first Z-axis symmetric parallel plate electrodes and the pair of second Z-axis symmetric parallel plate electrodes are fixed on a substrate parallel to the mass block assembly, and there is a gap with the torsion mass block; wherein the pair of first Z-axis symmetric parallel plate electrodes are symmetric about the X-axis, the pair of second Z-axis symmetric parallel plate electrodes are symmetric about the X-axis, and the pair of first Z-axis symmetric parallel plate electrodes and the pair of second Z-axis symmetric parallel plate electrodes are symmetric about the Y-axis;

[0018] A pair of first Z-axis symmetric parallel plate electrodes and a movable parallel plate electrode mounted on the top or bottom of the torsion mass form a pair of parallel plate capacitors;

[0019] A pair of second Z-axis symmetric parallel plate electrodes and a movable parallel plate electrode mounted on the top or bottom of the torsion mass form a pair of parallel plate capacitors;

[0020] The two pairs of parallel plate capacitors are in a centrally symmetrical structure in the initial state.

[0021] As a preferred embodiment of the present invention, the pair of first Z-axis variable spacing driving electrodes and the pair of second Z-axis variable spacing driving electrodes are fixed on a substrate parallel to the mass block assembly, and there is a gap with the torsion mass block; wherein the pair of first Z-axis variable spacing driving electrodes are symmetrical about the X-axis, the pair of second Z-axis variable spacing driving electrodes are symmetrical about the X-axis, and the pair of first Z-axis variable spacing driving electrodes and the pair of second Z-axis variable spacing driving electrodes are symmetrical about the Y-axis;

[0022] A pair of first Z-axis variable pitch driving electrodes and a moving parallel plate electrode mounted on the top or bottom of the torsion mass form a pair of Z-axis variable pitch drivers;

[0023] A pair of second Z-axis variable pitch driving electrodes and a moving parallel plate electrode mounted on the top or bottom of the torsion mass form a pair of Z-axis variable pitch drivers;

[0024] The two pairs of variable pitch drivers are centrally symmetrical in structure.

[0025] As a preferred embodiment of the present invention, the X-axis decoupling spring has a smaller elastic coefficient in the X-axis and a larger elastic coefficient in the Y-axis and the Z-axis; the Y-axis decoupling spring has a smaller elastic coefficient in the Y-axis and a larger elastic coefficient in the X-axis and the Z-axis; the Y-axis torsional elastic beam has a smaller torsional elastic coefficient around the Y-axis and a larger torsional elastic coefficient around the X-axis and the Z-axis.

[0026] As a preferred embodiment of the present invention, the torsion mass block has a non-centrosymmetric seesaw structure.

[0027] As a preferred embodiment of the present invention, a method for detecting uniaxial acceleration includes:

[0028] Apply a DC voltage V with opposite signs to two pairs of symmetrical parallel plate electrodes on the target axis. di and -V di , resonant voltage A i sin(ω i t) and -A i sin(ω i t), carrier voltage A ci sin(ω ci t) and -A ci sin(ω ci t), obtain the signal of the intermediate mass block and demodulate it to obtain the target axis resonance amplitude and resonance frequency; where A i ,ω i Represents the resonant voltage amplitude and frequency, A ci ,ω ci represents the carrier voltage amplitude and frequency, t represents time, and the subscript i is any one of X, Y, and Z. When i=X, it corresponds to the detection of X-axis acceleration, when i=Y, it corresponds to the detection of Y-axis acceleration, and when i=Z, it corresponds to the detection of Z-axis acceleration;

[0029] The detected target axis resonance amplitude and resonance frequency are subtracted from the preset amplitude and frequency, and are multiplied by the preset weights of the resonance amplitude deviation and the preset weights of the resonance frequency deviation, respectively, and then summed and input into the PID controller to calculate the force balance feedback voltage, which is applied to the target axis driver after passing through the push-pull circuit to drive the corresponding mass block to keep the displacement constant. At this time, the force balance feedback voltage reflects the acceleration of the target axis.

[0030] As a preferred embodiment of the present invention, a method for detecting a single-axis angular velocity includes:

[0031] When the target axis generates angular velocity, the resonant frequencies of the two single axes other than the target axis are obtained by using a single-axis acceleration detection method;

[0032] The sum and difference of the resonant frequencies of the two single axes other than the target axis are obtained by respectively summing and subtracting them;

[0033] A sinusoidal signal with a frequency equal to the difference between the resonant frequencies is generated, and the sum of the resonant frequencies is multiplied, demodulated and low-pass filtered using the sinusoidal signal to obtain the target shaft angular velocity.

[0034] As a preferred embodiment of the present invention, when detecting angular velocity, two single axes except the target axis work in the amplitude modulation accelerometer working mode, that is, the preset weight of the resonance amplitude deviation is 1, and the preset weight of the resonance frequency deviation is set to 0.

[0035] The present invention designs a symmetrical parallel plate capacitor structure and applies a pair of voltages with opposite signs on it, including a DC voltage, a resonant voltage and a carrier voltage, and combines the PLL phase closed-loop control method to simultaneously realize the resonant drive, amplitude modulation detection and frequency modulation detection of the three-axis structure; on the one hand, when there is external acceleration, the parallel plate electrode connected to the mass block is displaced, and at this time the symmetrical parallel plate capacitor generates an eccentric resonant force, which is expressed as F d =4εAV d V a x / d 2 , where ε, A, V d 、V a , x, and d are dielectric constant, parallel plate overlap area, DC voltage, AC excitation voltage, displacement, and parallel plate gap, respectively. The resonant force produces a certain resonant amplitude under PLL control, that is, the displacement caused by acceleration is modulated into a resonant amplitude change; at the same time, due to the soft spring effect of the symmetrical parallel plate capacitor, the resonant frequency is approximately linearly related to the displacement of the parallel plate electrode connected to the mass block, and the expression is f = f 0 -2εAV d 2 x / (md 4 f 0 ), where f 0 is the initial resonant frequency, that is, the displacement caused by acceleration is frequency modulated into a resonant frequency change; the resonance amplitude change and the resonant frequency change caused by acceleration can be detected simultaneously through amplitude modulation-demodulation and phase-locked loop, and the difference is calculated by comparing with the preset amplitude and preset frequency, and the force balance feedback voltage can be obtained after weighted fusion and controller calculation. By applying it to the variable area comb driver, the position of the mass block can be maintained constant. At this time, the feedback voltage reflects the magnitude of acceleration; on the other hand, when there is a rotational angular velocity, the resonant structure shared by the two orthogonal axes is coupled by the Coriolis force, and the sum of the resonant frequencies of the two orthogonal axes contains the angular velocity information of the third orthogonal axis. The angular velocity can be obtained by multiplying, demodulating and low-pass filtering with a sinusoidal signal with a frequency equal to the difference between the resonant frequencies of the two orthogonal axes.

[0036] Since acceleration and angular velocity detection use the same mechanical structure and resonant detection principle, interference between signals is avoided, reliability is higher, and integration is higher. At the same time, since acceleration detection uses an amplitude modulation / frequency modulation composite detection method to reduce the temperature drift of the mechanical structure, the angular velocity uses a frequency modulation detection method with better scale factor stability.

[0037] In general, the technical solution conceived by the present invention has the following beneficial effects compared with the prior art:

[0038] (1) The present invention simplifies the structure and circuit by sharing the mechanical structure and electrodes, thereby improving the space utilization and integration of micromechanical devices, and has the advantages of simple processing technology, high integration, and miniaturization.

[0039] (2) In the present invention, both the accelerometer and the gyroscope operate in a resonant state and share a set of PLL control algorithms, which not only reduces the complexity of the control system but also avoids mutual interference between signals.

[0040] (3) The accelerometer of the present invention can flexibly operate in frequency modulation / amplitude modulation mode and its mixed mode. When the accelerometer operates in amplitude modulation and the gyroscope operates in frequency modulation, interference between the two in detection is avoided. The method is easy to implement in a digital controller. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a schematic diagram of a typical micromechanical accelerometer-gyroscope integrated structure in an embodiment of the present invention;

[0042] Figure 2 It is a schematic diagram of an XY axis integrated control method of a typical micro-mechanical accelerometer-gyroscope in an embodiment of the present invention;

[0043] Figure 3 Schematic diagram of a typical XZ axis integrated control method of a micromechanical accelerometer-gyroscope in an embodiment of the present invention;

[0044] Figure 4 It is a schematic diagram of a YZ axis integrated control method of a typical micro-mechanical accelerometer-gyroscope in an embodiment of the present invention; Figure 5 Schematic diagram of the working mode of the frequency modulation / amplitude modulation accelerometer in an embodiment of the present invention;

[0045] In all the drawings, the same reference numerals are used to represent the same structure, wherein: 1-intermediate mass block; 21-X-axis mass block, 22-first X-axis symmetric parallel plate electrode, 23-second X-axis symmetric parallel plate electrode, 24-first X-axis variable area comb-tooth electrode, 25-second X-axis variable area comb-tooth electrode, 26-X-axis decoupling spring, 27-X-axis mass block supporting spring; 31-Y-axis part including Y-axis mass block, 32-first Y-axis symmetric parallel plate electrode, 33-second Y-axis symmetric parallel plate electrode, 34-first Y-axis variable area comb-tooth electrode, 35-second Y-axis variable area comb-tooth electrode, 36-Y-axis decoupling spring, 37-Y-axis mass block supporting spring; 41-torsion mass block, 42-first Z-axis symmetric parallel plate electrode, 43-second Z-axis symmetric parallel plate electrode, 44-first Z-axis variable spacing driving electrode, 45-second Z-axis variable spacing driving electrode, 46-Y-axis torsion elastic beam; 5-anchor area. DETAILED DESCRIPTION

[0046] In order to more clearly express the purpose, technical solutions and advantages of the present invention, further explanation is given below in conjunction with the accompanying drawings and formula derivations. It should be understood that the principles herein are used to explain the present invention, but are not limited to the present invention.

[0047] The highly integrated micromechanical accelerometer-gyroscope in the present invention shares a mechanical structure, and adopts an XYZ three-degree-of-freedom mass-spring-damper system as a common sensitive structure. For the convenience of explanation, it is structurally divided into a main mass block part, an X-axis part, a Y-axis part, a Z-axis part and an anchor area part; wherein the main mass block part is an intermediate mass block 1, and the X-axis part includes an X-axis mass block 21, a first X-axis symmetrical parallel plate electrode 22, a second X-axis symmetrical parallel plate electrode 23, a first X-axis variable area comb tooth electrode 24, a second X-axis variable area comb tooth electrode 25, an X-axis decoupling spring 26, and an X-axis symmetrical parallel plate electrode 27. The Y-axis portion includes a Y-axis mass block supporting spring 27; the Y-axis portion includes a Y-axis mass block 31, a first Y-axis symmetrical parallel plate electrode 32, a second Y-axis symmetrical parallel plate electrode 33, a first Y-axis variable area comb tooth electrode 34, a second Y-axis variable area comb tooth electrode 35, a Y-axis decoupling spring 36 and a Y-axis mass block supporting spring 37; the Z-axis portion includes a torsional mass block 41, a first Z-axis symmetrical parallel plate electrode 42, a second Z-axis symmetrical parallel plate electrode 43, a first Z-axis variable spacing driving electrode 44, a second Z-axis variable spacing driving electrode 45 and a Y-axis torsional elastic beam 46; the anchor area portion is uniformly defined as the anchor area 5.

[0048] Functionally, micromechanical accelerometer-gyroscopes include:

[0049] The mass block assembly is symmetrical about the Y axis, including an intermediate mass block 1, a torsion mass block 41 located inside the intermediate mass block, and a pair of X-axis mass blocks 21 and a pair of Y-axis mass blocks 31 symmetrically distributed around the intermediate mass block about the center; the X-axis mass block 21 and the Y-axis mass block 31 are connected to the intermediate mass block 1 through an X-axis decoupling spring 26 and a Y-axis decoupling spring 36, respectively, and are connected to the anchor area 5 through an X-axis mass block support spring 27 and a Y-axis mass block support spring 37, respectively; the torsion mass block 41 is connected to the intermediate mass block 1 through a pair of Y-axis torsion elastic beams 46; the mass block assembly is located in the same XY plane. Preferably, the torsion mass block 41 is a cross-like structure, and the four ends of the cross-like structure point to the four quadrants, and the whole is a seesaw structure symmetrical about the Y axis, and the intermediate mass block is located outside the torsion mass block, and its structure is similar.

[0050] The XYZ-axis symmetric parallel plate capacitor comprises a pair of first X-axis symmetric parallel plate electrodes 22 located in the negative direction of the X-axis, a pair of second X-axis symmetric parallel plate electrodes 23 located in the positive direction of the X-axis, a pair of first Y-axis symmetric parallel plate electrodes 32 located in the negative direction of the Y-axis, a pair of second Y-axis symmetric parallel plate electrodes 33 located in the positive direction of the Y-axis, and a pair of first Z-axis symmetric parallel plate electrodes 42 and a pair of second Z-axis symmetric parallel plate electrodes 43 located on the same side of the Z-axis; the above-mentioned symmetric parallel plate electrodes are fixed on the anchor area 5 or the substrate.

[0051] The XYZ axis driver comprises an XY axis variable area comb tooth driver and a Z axis variable spacing driver, wherein the XY axis variable area comb tooth driver comprises a first X axis variable area comb tooth electrode 24 located in the negative direction of the X axis, a second X axis variable area comb tooth electrode 25 located in the positive direction of the X axis, a first Y axis variable area comb tooth electrode 34 located in the negative direction of the Y axis, and a second Y axis variable area comb tooth electrode 35 located in the positive direction of the Y axis; the Z axis variable spacing driver comprises a pair of first Z axis variable spacing driving electrodes 44 and a pair of second Z axis variable spacing driving electrodes 45 located on the same side of the Z axis; the above-mentioned fixed electrodes are fixed on the anchor area 5 or the substrate.

[0052] like Figure 1As shown, in the present invention, a pair of X-axis mass blocks 21 and an intermediate mass block 1 are superimposed to form a resonant equivalent mass in the X-axis direction, an X-axis mass block support spring 27 and an X-axis decoupling spring 26 are connected in parallel to form a resonant equivalent spring in the X-axis direction, and a pair of Y-axis mass blocks 31 and an intermediate mass block 1 are superimposed to form a resonant equivalent mass in the Y-axis direction, and a Y-axis mass block support spring 37 and a Y-axis decoupling spring 36 are connected in parallel to form a resonant equivalent spring in the Y-axis direction. The X-axis decoupling spring 26 has a lower elastic coefficient in the X-axis and a larger elastic coefficient in the Y-axis and Z-axis; the Y-axis decoupling spring 36 has a lower elastic coefficient in the Y-axis and a larger elastic coefficient in the X-axis and Z-axis; the intermediate mass block 1 and the torsion mass block 41 are the sensitive mass of the Z-axis gyroscope, and the torsion elastic beam Y-axis torsion elastic beam has a lower torsion elastic coefficient around the Y-axis and a larger elastic coefficient on other axes.

[0053] The movable parallel plates of the three-axis symmetrical parallel plate capacitor are respectively fixedly connected to the three-axis mass block. A DC voltage, an AC excitation voltage and a carrier voltage with opposite signs are applied to a pair of fixed parallel plate electrodes. The displacement signal of the mass block can be obtained by carrier demodulation and low-pass filtering of the signal of the movable parallel plate electrode; the DC voltage and the AC excitation voltage can simultaneously realize the resonant drive and its amplitude / frequency modulation. The two working modes are as follows: Figure 5 As shown, the amplitude modulation modulates the displacement of the moving parallel plate caused by acceleration into a change in the resonance amplitude, and the frequency modulation modulates the displacement of the moving parallel plate caused by acceleration into a change in the resonance frequency. In the case of small displacement, the change in the resonance amplitude and the change in the resonance frequency are approximately linearly related to the displacement.

[0054] The detection of the resonant frequency change is to amplify the moving parallel plate electrode signal through the CV circuit, first multiply and demodulate it with the carrier voltage signal, and then multiply and demodulate it with the AC excitation voltage and the AC excitation voltage with a phase difference of 180 degrees and low-pass filter it to obtain two intermediate quantities, and then obtain the division result of the two intermediate quantities, and obtain the phase quantity through the inverse tangent operation, and obtain the feedback frequency adjustment quantity by comparing it with the preset -90 degree phase and calculating the difference through the controller, which is used to change the AC excitation voltage frequency, that is, to obtain the resonant frequency through the phase-locked loop PLL.

[0055] The force balance accelerometer compares the resonant amplitude and resonant frequency with the preset amplitude and preset frequency respectively to obtain the difference. After weighted fusion and controller calculation, the force balance feedback voltage can be obtained. By applying it to the variable area comb driver, the position of the mass block can be maintained constant. At this time, the feedback voltage reflects the magnitude of acceleration; the resonant amplitude is jointly determined by the DC voltage, AC excitation voltage, displacement of the moving parallel plate, stiffness of the resonant structure and the quality factor. The amplitude modulation sensitivity can be improved by increasing the DC voltage, AC excitation voltage and quality factor; the resonant frequency is jointly determined by the mass block and stiffness, DC voltage and angular velocity of the three-axis resonant structure. In the force balance control, the resonant frequency deviation weight is reset to zero to make the resonant frequency open-loop. At this time, the long-term change of the resonant frequency can reflect the temperature change and can be used for temperature drift compensation; when there is a Z-axis angular velocity, the sum of the resonant frequencies of the XY axes will be modulated by the Z angular velocity, and can further work in the Lissajous frequency modulation gyroscope mode; the angular velocities of the X and Y axes can be detected in the same way.

[0056] The shared three-axis mechanical structure satisfies the two-axis resonance state under the accelerometer amplitude modulation working mode. The difference between the two-axis resonant frequencies can be adjusted to a preset frequency difference by changing the DC voltage on the symmetrical parallel plate capacitor of the three axes. The two-axis resonant frequencies can be detected through the PLL closed loop and the difference between the two resonant frequencies and the sum of the two resonant frequencies can be calculated respectively to generate a sinusoidal signal (frequency is the difference between the two resonant frequencies), which is then multiplied and demodulated with the sum of the two resonant frequencies. The angular velocity can be obtained after low-pass filtering.

[0057] For clarity, the three-axis acceleration and three-axis angular velocity measurements are expressed separately. Figure 2 For XY axis acceleration and Z axis angular velocity detection, Figure 3 For XZ axis acceleration and Y axis angular velocity detection, Figure 4 It detects the YZ axis acceleration and X axis angular velocity.

[0058] like Figure 2 and Figure 3 As shown, the first X-axis symmetrical parallel plate electrode 22 and the movable plate electrode fixedly connected to the left side of the left X-axis mass block form a pair of parallel plate capacitors, and the second X-axis symmetrical parallel plate electrode 23 and the movable plate electrode fixedly connected to the right side of the right X-axis mass block form a pair of parallel plate capacitors. The two pairs of parallel plate capacitors are symmetrical structures, that is, the overlapping areas are the same and the initial gaps are the same. When the X-axis equivalent mass produces a motion displacement under the action of the X-axis acceleration, a DC voltage V with opposite signs is applied to the two pairs of parallel plate capacitors. dx and -V dx , resonant voltage A x sin(ω x t) and -A x sin(ω x t) and carrier voltage A cx sin(ωcx t) and -A cx sin(ω cx t), the motion displacement can be obtained through CV circuit and carrier demodulation. Since the equivalent mass of the X-axis deviates from the initial middle position, the DC voltage and AC excitation voltage on the parallel plate capacitor work together to generate a driving force with the same frequency as the AC excitation voltage. The driving force is related to the displacement, DC voltage and AC excitation voltage. The X-axis structure can be resonated through phase-locked loop PLL control, and the X-axis resonance amplitude and resonance frequency can be obtained through secondary demodulation, low-pass filtering and inverse tangent operation. The first X-axis variable area comb tooth electrode 24 and the mobile comb teeth fixedly connected to the right side of the left X-axis mass block form a group of variable area comb tooth drivers, and the second X-axis variable area comb tooth electrode 25 and the mobile comb teeth fixedly connected to the left side of the right X-axis mass block form a group of variable area comb tooth drivers; by comparing the detected X-axis resonance amplitude and resonance frequency with the preset amplitude T x The difference is compared with the frequency, and the sum is input into the first PID controller after multiplication by the preset weight. The force balance feedback voltage can be calculated and applied to the first X-axis variable area comb electrode 24 and the second X-axis variable area comb electrode 25 after passing through the push-pull circuit, driving the displacement of the X-axis mass block to remain constant. At this time, the force balance feedback voltage reflects the X-axis acceleration a x .

[0059] like Figure 2 and Figure 4 As shown, the first Y-axis symmetrical parallel plate electrode 32 and the movable plate electrode fixedly connected to the lower side of the lower Y-axis mass block form a pair of parallel plate capacitors, and the second Y-axis symmetrical parallel plate electrode 33 and the movable plate electrode fixedly connected to the upper side of the upper X-axis mass block form a pair of parallel plate capacitors. The two pairs of parallel plate capacitors are symmetrical structures, that is, the overlapping areas are the same and the initial gaps are the same. When the Y-axis equivalent mass produces a motion displacement under the action of the Y-axis acceleration, a DC voltage V with opposite signs is applied to the two pairs of parallel plate capacitors. dy and -V dy , resonant voltage A y sin(ω y t) and -A y sin(ω y t) and carrier voltage A cy sin(ω cy t) and -A cy sin(ω cyt), the motion displacement can be obtained through CV circuit and carrier demodulation. Since the Y-axis equivalent mass deviates from the initial middle position, the DC voltage and AC excitation voltage on the parallel plate capacitor work together to generate a driving force with the same frequency as the AC excitation voltage. The driving force is related to the displacement, DC voltage and AC excitation voltage. The Y-axis structure can be resonated through phase-locked loop PLL control, and the Y-axis resonance amplitude and resonance frequency can be obtained through secondary demodulation, low-pass filtering and inverse tangent operation. The first Y-axis variable area comb tooth electrode 34 and the mobile comb teeth fixedly connected to the upper side of the lower Y-axis mass block form a group of variable area comb tooth drivers, and the second Y-axis variable area comb tooth electrode 35 and the mobile comb teeth fixedly connected to the lower side of the upper Y-axis mass block form a group of variable area comb tooth drivers; by comparing the detected Y-axis resonance amplitude and resonance frequency with the preset amplitude T y The difference is compared with the frequency, and the sum is input into the second PID controller after multiplication by the preset weight. The force balance feedback voltage can be calculated and applied to the first Y-axis variable area comb electrode 34 and the second Y-axis variable area comb electrode 35 after passing through the push-pull circuit to drive the displacement of the Y-axis mass block to remain constant. At this time, the force balance feedback voltage reflects the Y-axis acceleration a y .

[0060] like Figure 3 and Figure 4 As shown, the first Z-axis symmetrical parallel plate electrode 42 and the movable plate electrode fixedly connected to the left bottom of the torsion mass block 41 form a pair of parallel plate capacitors, and the second Z-axis symmetrical parallel plate electrode 43 and the movable plate electrode fixedly connected to the right bottom of the torsion mass block 41 form a pair of parallel plate capacitors. The two pairs of parallel plate capacitors are symmetrical structures, that is, the overlapping areas are the same and the initial gaps are the same. When the torsion mass block generates a motion displacement under the action of the Z-axis acceleration, a DC voltage V with opposite signs is applied to the two pairs of parallel plate capacitors. dz and -V dz , resonant voltage A z sin(ω z t) and -A y sin(ω y t) and carrier voltage A cz sin(ω cz t) and -A cz sin(ω czt), the motion displacement can be obtained through CV circuit and carrier demodulation. As the torsional mass deviates from the initial middle position, the DC voltage and resonant voltage on the parallel plate capacitor work together to generate a driving force with the same frequency as the resonant voltage. The magnitude of the driving force is related to the displacement, DC voltage and AC excitation voltage. The Z-axis structure can be resonated through phase-locked loop PLL control, and the Z-axis resonant amplitude and resonant frequency can be obtained through secondary demodulation, low-pass filtering and inverse tangent operation. The first Z-axis variable spacing drive electrode 44 and the mobile plate electrode fixedly connected to the left side of the bottom of the torsional mass block form a group of variable spacing drivers, and the second Z-axis variable spacing drive electrode 45 and the mobile plate electrode fixedly connected to the right side of the bottom of the torsional mass block form a group of variable spacing drivers. By comparing the detected Z-axis resonant amplitude and resonant frequency with the preset amplitude T z The difference is compared with the frequency, and the sum is input into the third PID controller and PWM modulator after multiplication by the preset weight. The force balance feedback voltage can be calculated and applied to the first Z-axis variable spacing drive electrode 44 and the second Z-axis variable spacing drive electrode 45 after passing through the push-pull circuit to drive the torsion mass block to remain constant. At this time, the force balance feedback voltage reflects the Z-axis acceleration a z .

[0061] As a preferred embodiment, the preset weight of the resonance frequency deviation can be set to 0, and the preset weight of the resonance amplitude deviation is set to 1. At this time, the accelerometer works in the amplitude modulation mode;

[0062] like Figure 2 As shown, in the above-mentioned amplitude modulation accelerometer working mode, by summing the detected X-axis and Y-axis resonant frequencies respectively (ω x +ω y ) and the difference (ω x -ω y ), a frequency of (ω x -ω y ) of the sinusoidal signal sin(ω x t-ω y t), use this sinusoidal signal to compare the X-axis and Y-axis frequencies (ω x +ω y ) is multiplied and demodulated and low-pass filtered to obtain the Z-axis angular velocity Ω z .

[0063] like Figure 3 As shown, in the above-mentioned amplitude modulation accelerometer working mode, by summing the detected X-axis and Z-axis resonant frequencies respectively (ω x +ω z ) and the difference (ω x -ω z ), a frequency of (ω x -ω z) of the sinusoidal signal sin(ω x t-ω y t), use this sinusoidal signal to calculate the X-axis and Z-axis frequencies (ω x +ω z ) is multiplied and demodulated and low-pass filtered to obtain the Y-axis angular velocity Ω y .

[0064] like Figure 4 As shown, in the above-mentioned amplitude modulation accelerometer working mode, by summing the detected Y-axis and Z-axis resonant frequencies respectively (ω y +ω z ) and the difference (ω y -ω z ), a frequency of (ω y -ω z ) of the sinusoidal signal sin(ω y t-ω z t), use the sine signal to compare the Y-axis and Z-axis frequencies (ω y +ω z ) is multiplied and demodulated and low-pass filtered to obtain the X-axis angular velocity Ω x .

[0065] Those skilled in the art should understand that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A highly integrated micromechanical accelerometer-gyroscope, characterized in that: The XYZ three-degree-of-freedom mass-spring-damper system is used as the common sensitive structure, including: A mass block assembly is symmetrical about the Y axis, comprising an intermediate mass block (1), a torsion mass block (41) located inside the intermediate mass block, and a pair of X-axis mass blocks (21) and a pair of Y-axis mass blocks (31) symmetrically distributed around the intermediate mass block about the center; the X-axis mass block (21) and the Y-axis mass block (31) are connected to the intermediate mass block (1) via an X-axis decoupling spring (26) and a Y-axis decoupling spring (36), respectively, and are connected to the anchor area via an X-axis mass block support spring (27) and a Y-axis mass block support spring (37), respectively; the torsion mass block (41) is connected to the intermediate mass block (1) via a pair of Y-axis torsion elastic beams (46); and the mass block assembly is located in the same XY plane; An XYZ axisymmetric parallel plate capacitor, comprising a pair of first X axisymmetric parallel plate electrodes (22) located in the negative direction of the X axis, a pair of second X axisymmetric parallel plate electrodes (23) located in the positive direction of the X axis, a pair of first Y axisymmetric parallel plate electrodes (32) located in the negative direction of the Y axis, a pair of second Y axisymmetric parallel plate electrodes (33) located in the positive direction of the Y axis, and a pair of first Z axisymmetric parallel plate electrodes (42) and a pair of second Z axisymmetric parallel plate electrodes (43) located on the same side of the Z axis; An XYZ axis driver comprises an XY axis variable area comb tooth driver and a Z axis variable pitch driver, wherein the XY axis variable area comb tooth driver comprises a first X axis variable area comb tooth electrode (24) located in the negative direction of the X axis, a second X axis variable area comb tooth electrode (25) located in the positive direction of the X axis, a first Y axis variable area comb tooth electrode (34) located in the negative direction of the Y axis, and a second Y axis variable area comb tooth electrode (35) located in the positive direction of the Y axis; and the Z axis variable pitch driver comprises a pair of first Z axis variable pitch driving electrodes (44) and a pair of second Z axis variable pitch driving electrodes (45) located on the same side of the Z axis.

2. The highly integrated micromechanical accelerometer-gyroscope according to claim 1, characterized in that: The first X-axis symmetric parallel plate electrode (22) and the second X-axis symmetric parallel plate electrode (23) are fixed in the anchor area and are symmetrically distributed about the Y axis; The first X-axis variable-area comb-tooth electrode (24) and the second X-axis variable-area comb-tooth electrode (25) are fixed in the anchor area and are symmetrically distributed about the Y-axis; The first X-axis symmetrical parallel plate electrode (22) and a movable parallel plate electrode installed on the left / right side of an X-axis mass block (21) form a parallel plate capacitor, and the first X-axis variable area comb tooth electrode (24) and the movable comb teeth on the right / left side of the same X-axis mass block (21) form a comb tooth capacitor; The second X-axis symmetrical parallel plate electrode (23) forms a parallel plate capacitor with a movable parallel plate electrode installed on the right / left side of another X-axis mass block (21), and the second X-axis variable area comb tooth electrode (25) forms a comb tooth capacitor with the movable comb teeth on the left / right side of the same X-axis mass block (21).

3. The highly integrated micromechanical accelerometer-gyroscope according to claim 1, characterized in that: The first Y-axis symmetric parallel plate electrode (32) and the second Y-axis symmetric parallel plate electrode (33) are fixed in the anchor area and are symmetrically distributed about the X-axis; The first Y-axis variable-area comb-tooth electrode (34) and the second Y-axis variable-area comb-tooth electrode (35) are fixed in the anchor area and are symmetrically distributed about the X-axis; A first Y-axis symmetrical parallel plate electrode (32) and a movable parallel plate electrode mounted on the lower side / upper side of a Y-axis mass block (31) form a parallel plate capacitor, and a first Y-axis variable area comb tooth electrode (34) and movable comb teeth on the upper side / lower side of the same Y-axis mass block (31) form a comb tooth capacitor; The second Y-axis symmetrical parallel plate electrode (33) forms a parallel plate capacitor with a movable parallel plate electrode mounted on the upper side / lower side of another Y-axis mass block (31), and the second Y-axis variable area comb tooth electrode (35) forms a comb tooth capacitor with the movable comb teeth on the lower side / upper side of the same Y-axis mass block (31).

4. The highly integrated micromechanical accelerometer-gyroscope according to claim 1, characterized in that: The pair of first Z-axis symmetric parallel plate electrodes (42) and the pair of second Z-axis symmetric parallel plate electrodes (43) are fixed on a substrate parallel to the mass block assembly, with a gap between them and the torsion mass block (41); wherein the pair of first Z-axis symmetric parallel plate electrodes (42) are symmetric about the X-axis, the pair of second Z-axis symmetric parallel plate electrodes (43) are symmetric about the X-axis, and the pair of first Z-axis symmetric parallel plate electrodes (42) and the pair of second Z-axis symmetric parallel plate electrodes (43) are symmetric about the Y-axis; A pair of first Z-axis symmetrical parallel plate electrodes (42) and a movable parallel plate electrode mounted on the top or bottom of the torsion mass block (41) form a pair of parallel plate capacitors; A pair of second Z-axis symmetrical parallel plate electrodes (43) and a movable parallel plate electrode mounted on the top or bottom of the torsion mass block (41) form a pair of parallel plate capacitors; The two pairs of parallel plate capacitors are in a centrally symmetrical structure in the initial state.

5. The highly integrated micromechanical accelerometer-gyroscope according to claim 1, characterized in that: The pair of first Z-axis variable-spacing driving electrodes (44) and the pair of second Z-axis variable-spacing driving electrodes (45) are fixed on a substrate parallel to the mass block assembly, with a gap between them and the torsion mass block (41); wherein the pair of first Z-axis variable-spacing driving electrodes (44) are symmetrical about the X-axis, the pair of second Z-axis variable-spacing driving electrodes (45) are symmetrical about the X-axis, and the pair of first Z-axis variable-spacing driving electrodes (44) and the pair of second Z-axis variable-spacing driving electrodes (45) are symmetrical about the Y-axis; A pair of first Z-axis variable pitch driving electrodes (44) and a movable parallel plate electrode mounted on the top or bottom of the torsion mass block (41) form a pair of Z-axis variable pitch drivers; A pair of second Z-axis variable pitch driving electrodes (45) and a movable parallel plate electrode mounted on the top or bottom of the torsion mass block (41) form a pair of Z-axis variable pitch drivers; The two pairs of variable pitch drivers are centrally symmetrical in structure.

6. The highly integrated micromechanical accelerometer-gyroscope according to claim 1, characterized in that: The X-axis decoupling spring (26) has a smaller elastic coefficient on the X-axis and a larger elastic coefficient on the Y-axis and the Z-axis; the Y-axis decoupling spring (36) has a smaller elastic coefficient on the Y-axis and a larger elastic coefficient on the X-axis and the Z-axis; the Y-axis torsional elastic beam (46) has a smaller torsional elastic coefficient around the Y-axis and a larger torsional elastic coefficient around the X-axis and the Z-axis.

7. The highly integrated micromechanical accelerometer-gyroscope according to claim 1, characterized in that: The torsion mass block (41) presents a non-centrosymmetric seesaw structure.

8. The highly integrated micromechanical accelerometer-gyroscope according to claim 1, characterized in that: The detection method of uniaxial acceleration includes: Apply a DC voltage V with opposite signs to two pairs of symmetrical parallel plate electrodes on the target axis. di and -V di , resonant voltage A i sin(ω i t) and -A i sin(ω i t), carrier voltage A ci sin(ω ci t) and -A ci sin(ω ci t), obtain the signal of the intermediate mass block and demodulate it to obtain the target axis resonance amplitude and resonance frequency; where A i ,ω i Represents the resonant voltage amplitude and frequency, A ci ,ω ci represents the carrier voltage amplitude and frequency, t represents time, and the subscript i is any one of X, Y, and Z. When i=X, it corresponds to the detection of X-axis acceleration, when i=Y, it corresponds to the detection of Y-axis acceleration, and when i=Z, it corresponds to the detection of Z-axis acceleration; The detected target axis resonance amplitude and resonance frequency are subtracted from the preset amplitude and frequency, and are multiplied by the preset weights of the resonance amplitude deviation and the preset weights of the resonance frequency deviation, respectively, and then summed and input into the PID controller to calculate the force balance feedback voltage, which is applied to the target axis driver after passing through the push-pull circuit to drive the corresponding mass block to keep the displacement constant. At this time, the force balance feedback voltage reflects the acceleration of the target axis.

9. The highly integrated micromechanical accelerometer-gyroscope according to claim 8, characterized in that: The method for detecting single-axis angular velocity includes: When the target axis generates angular velocity, the resonant frequencies of the two single axes other than the target axis are obtained by using a single-axis acceleration detection method; The sum and difference of the resonant frequencies of the two single axes other than the target axis are obtained by respectively summing and subtracting them; A sinusoidal signal with a frequency equal to the difference between the resonant frequencies is generated, and the sum of the resonant frequencies is multiplied, demodulated and low-pass filtered using the sinusoidal signal to obtain the target shaft angular velocity.

10. The highly integrated micromechanical accelerometer-gyroscope according to claim 9, characterized in that: When detecting the angular velocity, the two single axes other than the target axis work in the amplitude modulation accelerometer working mode, that is, the preset weight of the resonance amplitude deviation is 1, and the preset weight of the resonance frequency deviation is set to 0.

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