A method for real-time suppression of zero bias drift of a symmetrical gyroscope and improvement of zero bias stability

Abstract

The application discloses a method for real-time suppression of zero bias drift and improvement of zero bias stability of a symmetrical gyroscope, which comprises the following steps: after a micro-electro-mechanical gyroscope is powered on, the working mode of the micro-electro-mechanical gyroscope is periodically exchanged, a damping angle is obtained by real-time identification during the mode exchange, and the damping angle is added to the mode angle of the corresponding working mode after the mode exchange. The application is applied to the field of micro-electro-mechanical gyroscopes, and the damping axis deflection angle error of the mode deflection micro-electro-mechanical gyroscope is identified and corrected on-line, and the traditional mode exchange technology of the gyroscope is combined skillfully, so that the application does not need to introduce any physical mechanism, has no special requirement on the processing technology of the gyroscope, is easy to operate, is stable and reliable, does not introduce additional test and calibration steps, can realize real-time self-calibration and self-compensation of the zero bias output of the gyroscope, improves the zero bias stability of the gyroscope and the repeatability of the gyroscope, and can effectively meet the demand of the military and civilian markets on high-precision micro-electro-mechanical gyroscopes.

Description

Technical Field

[0001] This invention relates to the field of microelectromechanical gyroscope technology, specifically a method for real-time suppression of zero-bias drift and improvement of zero-bias stability in symmetrical gyroscopes. Background Technology

[0002] In recent years, with the rapid development of MEMS technology, microelectromechanical gyroscopes (MEMS) have demonstrated unique advantages in precision guidance, unmanned platforms, and north-finding orientation due to their inherent characteristics such as small size, low weight, low power consumption, and low cost. However, zero-bias drift of MEMS gyroscopes has become a bottleneck in the development of high-precision MEMS gyroscopes.

[0003] While temperature compensation techniques commonly used in this field can effectively compensate for temperature-induced drift in microelectromechanical gyroscopes (MEMS), they do not suppress the slow drift of the gyroscope along its damping axis inherent in the gyroscope structure itself at constant temperatures. On-chip temperature control can also suppress temperature-induced drift, but it requires an additional on-chip temperature control device and places special demands on the gyroscope's manufacturing process, significantly increasing its cost. Furthermore, this method only suppresses temperature-induced drift, not structural drift. The dynamic adjustment and balancing technique proposed by Siemens can effectively identify and compensate for the zero-bias error of MEMS gyroscopes; however, this method requires special manufacturing processes, increasing the difficulty of manufacturing MEMS gyroscopes and hindering their mass production and cost reduction.

[0004] Modal exchange technology can perform real-time differential self-calibration of the slow drift zero-bias error of a gyroscope structure along the damping axis. However, since it cannot track the damping axis in real time, there is still a possibility of further suppression of zero-bias drift across the entire temperature range. Mode shape deflection technology can strongly suppress the gyroscope's drift with temperature, but currently, the calibration of the damping angle needs to be performed offline, and since the damping angle may change with environmental factors such as temperature, the timeliness of the calibration has not yet been verified.

[0005] In summary, there is currently no online identification and correction method for the damped axis deviation error of microelectromechanical gyroscopes (MEMS). Therefore, for MEMS gyroscopes, there is a need for a method that can achieve zero-bias error identification and self-compensation without additional structures and calibration steps, thereby improving the accuracy of MEMS gyroscopes while effectively reducing their system complexity. Summary of the Invention

[0006] To address the shortcomings of the existing technologies, this invention provides a method for real-time suppression of zero-bias drift and improvement of zero-bias stability in symmetrical gyroscopes. This method cleverly combines online identification and correction of damping axis deviation error in microelectromechanical gyroscopes with traditional mode-switching technology. It eliminates the need for any physical mechanisms and places no special requirements on gyroscope manufacturing processes. Furthermore, it is easy to operate, stable, reliable, and requires no additional testing or calibration steps. This allows for real-time self-calibration and self-compensation of the gyroscope's zero-bias output, improving its zero-bias stability and repeatability. This effectively meets the demands of both military and civilian markets for high-precision microelectromechanical gyroscopes.

[0007] To achieve the above objectives, this invention provides a method for real-time suppression of zero-bias drift and improvement of zero-bias stability in a symmetrical gyroscope. After the microelectromechanical gyroscope is powered on, its operating modes are periodically exchanged, and the damping angle is identified in real time during the mode exchange. The damping angle is then superimposed on the mode shape angle of the corresponding operating mode after the mode exchange, thereby suppressing the zero-bias drift error of the microelectromechanical gyroscope and improving its zero-bias stability.

[0008] In one embodiment, the microelectromechanical gyroscope has a first mode and a second mode under force balance mode, wherein the mode shape angle of the first mode is α1 and the mode shape angle of the second mode is α2;

[0009] The method for real-time suppression of zero-bias drift and improvement of zero-bias stability of the symmetrical gyroscope includes the following steps:

[0010] Step 1: After the microelectromechanical gyroscope is powered on, control the microelectromechanical gyroscope to operate in a force balance mode with a mode angle of α1;

[0011] Step 2: After a preset time, control the microelectromechanical gyroscope to operate in full-angle precession mode, causing the mode shape angle of the microelectromechanical gyroscope to precess from α1 to α2, and identify the damping angle θ during the process of the mode shape angle precessing from α1 to α2. τ1 Then, the microelectromechanical gyroscope is controlled to operate at a mode angle of α2+θ. τ1 Under the force balance mode;

[0012] Step 3: After a preset time, control the microelectromechanical gyroscope to operate in full-angle precession mode, so that the mode angle of the microelectromechanical gyroscope changes from α2+θ. τ1 Precession to α1, and identification of the mode shape angle from α2+θ τ1 Damping angle θ during precession to α1 τ2 Then, the microelectromechanical gyroscope is controlled to operate at a mode angle of α1+θ. τ2 Under the force balance mode;

[0013] Step 4: After a preset time, control the microelectromechanical gyroscope to operate in full-angle precession mode, so that the mode angle of the microelectromechanical gyroscope changes from α1+θ. τ2 Precession to α2, and identification of the mode shape angle from α1+θ τ2 Damping angle θ during precession to α2 τ1 Then, the microelectromechanical gyroscope is controlled to operate at a mode angle of α2+θ. τ1 Under the force balance mode;

[0014] Step 5: Repeat steps 3 to 4 to achieve the identification and self-calibration of the damping axis of the microelectromechanical gyroscope, thereby improving the zero-bias stability of the microelectromechanical gyroscope.

[0015] In one embodiment, during the mode shape precession process in steps 2 to 4, the damping angle is obtained by fitting the curve of the driving force or the in-phase balancing force of the gyroscope's short axis in full-angle self-precession mode as a function of the mode shape angle.

[0016] In one embodiment, in steps 1 to 5, the virtual rotation of the microelectromechanical gyroscope's operating mode is achieved through a rotation control module. This rotation control module can be implemented by switching the microelectromechanical gyroscope's drive and detection operating mode closed-loop control circuit via a virtual digital switch. Alternatively, the rotation angle of the microelectromechanical gyroscope's drive and detection operating mode can be controlled through a virtual rotation closed-loop measurement and control circuit, both of which eliminate the need for a physical rotation mechanism.

[0017] In one embodiment, a timing controller is used to periodically switch the operating modes of the microelectromechanical gyroscope, calculating and compensating for the zero-bias error of the microelectromechanical gyroscope. A mode shape precession controller is used to calculate the mode shape angles of the microelectromechanical gyroscope's mode shape rotation. The timing controller and mode shape precession controller can be implemented through computer programming.

[0018] Compared with the prior art, the present invention has the following beneficial technical effects:

[0019] 1. This invention utilizes mode exchange control technology based on mode deflection to self-compensate the gyroscope zero bias error of a microelectromechanical gyroscope, without introducing additional calibration steps and additional physical mechanisms, which facilitates the miniaturization, portability, integration, and cost reduction of microelectromechanical gyroscopes.

[0020] 2. This invention utilizes a microelectromechanical gyroscope measurement and control circuit to achieve mode exchange control under mode deflection, which has the advantages of simple operation, stability and reliability, and ease of use. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the control method for real-time suppression of zero-bias drift and improvement of zero-bias stability of a symmetrical gyroscope in an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the honeycomb microelectromechanical gyroscope resonant structure in an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of the microelectromechanical gyroscope driving mode in an embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of the detection modes of the microelectromechanical gyroscope in an embodiment of the present invention;

[0026] Figure 5 This is a schematic diagram of frequency splitting between the driving mode and the detection mode of the microelectromechanical gyroscope in an embodiment of the present invention;

[0027] Figure 6 This is a schematic diagram of the quality factor of the microelectromechanical gyroscope driving mode in an embodiment of the present invention;

[0028] Figure 7 This is a schematic diagram of the quality factor of the microelectromechanical gyroscope detection mode in an embodiment of the present invention;

[0029] Figure 8 This is a schematic diagram of the equivalent system model of a two-degree-of-freedom vibrating gyroscope with error in an embodiment of the present invention;

[0030] Figure 9 This is a schematic diagram illustrating the principle of mode switching technology in an embodiment of the present invention;

[0031] Figure 10 This is a schematic diagram of the damping constraint on the harmonic oscillator and its equivalent orthogonal damping axis in an embodiment of the present invention, wherein: (a) is a schematic diagram before simplification, and (b) is a schematic diagram after simplification.

[0032] Figure 11 The graph shows the test results of the gyroscope damping angle and driving frequency changing with temperature in an embodiment of the present invention.

[0033] Figure 12 This is a schematic diagram illustrating the modal exchange control principle under mode shape deflection in an embodiment of the present invention.

[0034] Figure 13This is a schematic diagram of the timing controller in the modal exchange control method under mode deflection in an embodiment of the present invention;

[0035] Figure 14 This is a schematic diagram illustrating the working timing principle of the online identification and correction method for the damped axis deflection error of a microelectromechanical gyroscope based on mode deflection in an embodiment of the present invention.

[0036] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0038] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0039] This embodiment discloses a method for real-time suppression of zero-bias drift and improvement of zero-bias stability in a symmetrical gyroscope. This method utilizes the mode precession process during mode switching to complete the real-time identification of the damping angle, and superimposes the identified damping angle onto the driving mode angle during the next mode switching, thereby realizing online identification and self-compensation of damping error and real-time suppression of zero-bias drift in the microelectromechanical gyroscope. Specifically: After the microelectromechanical gyroscope is powered on, it is made to output in force balance mode; full-angle precession mode is used for mode rotation and damping angle identification, and the damping angle information is obtained by calculating the driving force of precession or the in-phase balancing force of the gyroscope's short axis; the working modes of the microelectromechanical gyroscope are periodically exchanged by the timing controller, the zero bias error of the microelectromechanical gyroscope is calculated and compensated, and the damping angle identification of mode deflection and the inter-mode mode rotation of mode exchange are realized by the mode precession controller; among them, the damping angle identification is obtained by inputting the full-angle precession mode output data obtained by mode precession into the data register for fitting calculation, and the identified damping angle information is calculated. This angle is superimposed on the driving mode angle of the next mode exchange.

[0040] The microelectromechanical gyroscope in this embodiment has a first mode and a second mode under force balance mode, wherein the mode shape angle of the first mode is α1 and the mode shape angle of the second mode is α2. The specific implementation process of the method for real-time suppression of zero-bias drift and improvement of zero-bias stability of symmetrical gyroscope includes the following steps:

[0041] Step 1: After the microelectromechanical gyroscope is powered on, control the microelectromechanical gyroscope to work in the force balance mode with a mode angle of α1;

[0042] Step 2: After a preset time, control the microelectromechanical gyroscope to operate in full-angle precession mode, causing the mode shape angle of the microelectromechanical gyroscope to precess from α1 to α2, and identify the damping angle θ during the process of the mode shape angle precessing from α1 to α2. τ1 Then control the microelectromechanical gyroscope to operate at a mode angle of α2+θ τ1 Under the force balance mode;

[0043] Step 3: After a preset time, control the microelectromechanical gyroscope to operate in full-angle precession mode, so that the mode angle of the microelectromechanical gyroscope changes from α2+θ τ1 Precession to α1, and identification of the mode shape angle from α2+θ τ1 Damping angle θ during precession to α1 τ2 Then control the microelectromechanical gyroscope to operate at a mode angle of α1+θ τ2 Under the force balance mode;

[0044] Step 4: After a preset time, control the microelectromechanical gyroscope to operate in full-angle precession mode, so that the mode angle of the microelectromechanical gyroscope changes from α1+θ τ2 Precession to α2, and identification of the mode shape angle from α1+θ τ2 Damping angle θ during precession to α2 τ1 Then control the microelectromechanical gyroscope to operate at a mode angle of α2+θ τ1 Under the force balance mode;

[0045] Step 5: Repeat steps 3 to 4 to achieve identification and self-calibration of the damping axis of the microelectromechanical gyroscope, thereby improving the zero-bias stability of the microelectromechanical gyroscope.

[0046] During the mode shape precession process in steps 2 to 4, the damping angle is obtained by fitting the curves of the driving force or the in-phase balancing force of the gyroscope's minor axis as a function of the mode shape angle in the full-angle self-precession mode of the microelectromechanical gyroscope. In steps 1 to 5, the virtual rotation of the microelectromechanical gyroscope's working mode is achieved through a rotation control module or a virtual rotation closed-loop measurement and control circuit.

[0047] refer to Figure 1This diagram illustrates modal exchange control based on mode shape deflection. The microelectromechanical gyroscope (MEMS) outputs data in a force balance mode and uses a full-angle precession mode for mode shape precession and damping angle identification. The damping angle information is obtained by calculating the driving force of the precession or the in-phase balancing force of the gyroscope's minor axis. Specifically, a timing controller controls the periodic exchange of the MEMS's working modes, calculating and compensating for the MEMS's zero-bias error. A mode shape precession controller enables damping angle identification for mode shape deflection and periodic rotation of the mode shape during mode exchange. The damping angle identification, achieved by inputting the full-angle precession mode output data obtained from mode shape precession into a data register for fitting calculation, yields the identified damping angle information. This angle is then superimposed on the driving mode shape angle for the next mode exchange.

[0048] The following specific examples further illustrate the method for real-time suppression of zero-bias drift and improvement of zero-bias stability in the symmetrical gyroscope of this embodiment.

[0049] refer to Figure 2 This is a schematic diagram of a honeycomb microelectromechanical gyroscope resonant structure. The resonant structure mainly consists of a central anchor point, spokes, a suspended mass, internal electrodes, and external electrodes. The biomimetic honeycomb topology can improve the overall fabrication symmetry and robustness of the resonant structure, and the design of the suspended mass can effectively improve the quality factor Q of the resonant structure. (Reference) Figures 3 to 7 This microelectromechanical gyroscope operates in a degenerate mode with n=2. The resonant frequency of the driving mode is approximately 4374.5 Hz, and the resonant frequency of the detection mode is approximately 4374.7 Hz. The quality factor Q of both modes is approximately 570,000. The initial frequency split of the operating mode is approximately 0.2 Hz. The detection mode corresponds to the first mode in this embodiment, with a mode shape angle α1 = 0°; the driving mode corresponds to the second mode in this embodiment, with a mode shape angle α2 = 90°.

[0050] refer to Figure 8 The diagram shows a two-degree-of-freedom equivalent system model of a vibrating gyroscope with errors. In this example, the dynamic model of the microelectromechanical gyroscope can be simplified to a two-degree-of-freedom lumped mass vibration model. The output of the gyroscope operating in force balance mode is:

[0051]

[0052] Where α is the mode shape angle of the driving and detection modes, x0 is the vibration amplitude of the driving mode, and ω x The driving mode operating frequency is given by t, time, Ω, external angular velocity output, k, angular gain factor, ω, average natural frequency, τ, average decay time constant, Δ, and θ. ω Let θ be the stiffness normal axis. τLet be the damping normal axis, i.e., the damping angle. According to formula (1), the zero-bias drift of the microelectromechanical gyroscope caused by the stiffness non-uniformity error Δω can be suppressed by the orthogonal error control loop because its phase relationship cosω x t and angular velocity output sinω x t are orthogonal. Therefore, formula (1) can be rewritten as:

[0053] G out (α)=SF·Ω-B sin2(α-θ τ (2)

[0054] Where SF is the scaling factor and B is the zero bias.

[0055] refer to Figure 9 This is a schematic diagram illustrating the principle of modal switching technology. The modal precession controller controls the precession of the mode shape and the periodic exchange between the drive control loop and the force balance loop. The switching of the mode shape is achieved by controlling the rotation of the mode shape angle α through the self-precession of the mode shape in the full-angle mode. At this point, when the external input angular velocity is zero, we can obtain:

[0056] G out (α)=-B sin2(α-θ τ (3)

[0057] When the mode reaches the next working mode after precession, the damping angle θ is obtained by solving the zero bias of the gyroscope during precession. τ1 or θ τ2 The mode shape angles of the driving and detection modes at 0° and 90° are superimposed on the working mode shape angles as the working mode shape angles after the next mode precession. When the driving and detection mode shape angles of the microelectromechanical gyroscope are 0°+θ, ... τ2 and 90°+θ τ1 At that time, the following result will be obtained:

[0058] G out (0°+θ τ2 )=B sin2(θ τ2 -θ τ (4)

[0059] G out (90°+θ τ1 )=-B sin2(θ τ1 -θ τ (5)

[0060] θ τ1 and θ τ2 Equal to the damping angle θ of the gyroscope at the previous moment τThis achieves real-time tracking of the gyroscope mode angle to the gyroscope damping angle. At this point, both equations (4) and (5) are approximately zero, and the zero bias of the gyroscope is eliminated by real-time tracking of the damping angle. Furthermore, by adding equations (4) and (5), differential calibration of the gyroscope output is achieved, suppressing the zero bias of the gyroscope. The zero-rate output of the gyroscope at this point can be expressed as:

[0061] G out (α)=B sin2(θ τ2 -θ τ )-Bsin2(θ τ1 -θ τ )=0 (6)

[0062] It can be seen that when the angles of the mode shapes are superimposed, the angle θ τ1 and θ τ2 Exactly equal to the damping angle θ τ At this time, the zero-rate output error of the gyroscope is doubly suppressed, and the gyroscope output is no longer sensitive to environmental factors such as temperature.

[0063] refer to Figure 10 The diagram illustrates the damping constraint on the resonator and its equivalent orthogonal damping axis. The motion of the microelectromechanical gyroscope resonator can be equivalent to the vibration of a single particle in a two-dimensional plane. The particle may actually be subject to thermoelastic damping τ. a Support loss τ b Surface loss τ c Air damping τ d Akhiezer damping τ e Various damping constraints in different directions can be equivalently regarded as a pair of virtual orthogonal damping constraints τ1 and τ2. This pair of orthogonal damping constraints is defined as the principal damping axis, which corresponds to the maximum and minimum damping directions of the resonator along the two axes, respectively. The damping difference between the two directions determines the magnitude of the zero bias B in formulas (2) to (6). When the resonator is affected by environmental factors such as large driving force or temperature changes, the various forms of damping experienced by the resonator will change, which will cause changes in the equivalent damping axis direction and the magnitude of the damping difference, thus causing zero bias drift. Therefore, real-time alignment of the mode shape angle with the current damping angle can suppress the zero bias drift of the gyroscope to the greatest extent and ensure better environmental adaptability and stability.

[0064] refer to Figure 11 The figure shows the test results of the gyroscope's damping angle and drive frequency as a function of temperature. Within a temperature range of 30–60°C, the gyroscope's damping angle changed by approximately 0.2 degrees. Therefore, real-time identification and online alignment of the damping angle are crucial for suppressing zero-bias drift in the gyroscope.

[0065] refer to Figure 12This is a schematic diagram illustrating the modal exchange control principle under modal deflection. The purpose of the modal precession controller is to realize the periodic alternation of the driving and detection modal angles α of the microelectromechanical gyroscope between α1 and α2. The modal precession control module controls α to perform modal precession. This is achieved using a full-angle self-precession mode. In this mode, the control forces f applied to the gyroscope along the x and y axes by the driving and detection electrodes... x and f y It changes with the rotation of the mode angle α, and can be expressed as:

[0066] f x =F a cosα-F q sinα (7)

[0067] f y =F a sinα+F q cosα (8)

[0068] Among them, F a and F q They are respectively Figure 12 The driving force and orthogonal force actually applied to the major axis a and minor axis q. F a and F q It can be expressed in the form of in-phase and quadrature quantities as follows:

[0069]

[0070]

[0071] Among them, f ac and f as F respectively a In-phase and quadrature quantities, f qc and f qs F respectively q The in-phase and quadrature quantities. When the input angular velocity is zero, the in-phase balancing force of the minor axis is:

[0072] f qs =B sin2(α-θ) τ (11)

[0073] Where B is zero bias, f qs It changes with the mode angle α, and in practical applications, it can be fitted by f. qs The damping angle θ is obtained by identifying the output curve as a function of α. τ The value of .

[0074] Specifically, in full-angle mode, the driving force f as The in-phase balancing force f of the gyroscope's minor axis qsBoth can be used to identify the damping angle. Since the driving force is more sensitive to temperature, this embodiment uses the in-phase balancing force f of the gyroscope's short axis. qs The damping angle is identified. The identification principle is shown in formula (11), and the unknown parameters are solved using the objective function shown in formula (12). The physical quantities in formula (12) are correlated with those in formula (11), and y is represented as f. qs Let x represent α, and a and b be the parameters to be determined. By substituting the data obtained from the mode precession process into the objective function formula (12), the parameters a and b can be obtained. Referring to formula (11), the damping angle θ can be obtained. τ =b.

[0075] y = a·sin[2(xb)] (12)

[0076] refer to Figure 13 This is a schematic diagram of the timing controller in the modal exchange control method under modal deflection. The timing controller is mainly responsible for controlling the periodic switching of the gyroscope between the operating mode and the modal precession mode, and for controlling the identified damping angle as the driving mode angle for the next operating mode. This completes the modal exchange control of the microelectromechanical gyroscope under modal deflection. (Reference) Figure 14 This is a schematic diagram illustrating the working principle of an online identification and correction method for damped axisymmetric error in a microelectromechanical gyroscope based on mode shape deflection. After power-on, the gyroscope operates in force balance mode with a mode shape angle α of 0°. After a set operating time, the gyroscope operates in full-angle mode, and the mode shape angle α precesses from 0° to 90°. The gyroscope damping angle θ during this stage is obtained using the zero-bias identification during this process. τ1 The gyroscope then operates in force balance mode, with the mode shape angle set to 90° + θ. τ1 After the set working time, the gyroscope switches to full-angle mode, and the mode shape angle α changes from 90°+θ. τ1 The gyro precesses to 0°, and the zero-bias identification during this process yields the gyro damping angle θ for this stage. τ2 Subsequently, the gyroscope operates in force balance mode, with the mode shape angle set to 0°+θ. τ2 The above four steps are then repeated continuously to achieve the identification and self-calibration of the damping shaft.

[0077] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for real-time suppression of zero-bias drift and improvement of zero-bias stability in a symmetrical gyroscope, characterized in that, After the microelectromechanical gyroscope is powered on, the working modes of the microelectromechanical gyroscope are periodically exchanged, and the damping angle is identified in real time during the mode exchange process. The damping angle is then superimposed on the mode angle of the corresponding working mode after the mode exchange. The microelectromechanical gyroscope has a first mode and a second mode under force balance mode, wherein the mode shape angle of the first mode is... The mode shape angle of the second mode is ; The method for real-time suppression of zero-bias drift and improvement of zero-bias stability of the symmetrical gyroscope includes the following steps: Step 1: After the microelectromechanical gyroscope is powered on, control the microelectromechanical gyroscope to operate at a mode angle of [value missing]. Under the force balance mode; Step 2: After a preset time, control the microelectromechanical gyroscope to operate in full-angle precession mode, so that the mode angle of the microelectromechanical gyroscope changes from... Precession And identify the mode angle from Precession Damping angle during the process Then control the microelectromechanical gyroscope to operate at a mode angle of... Under the force balance mode; Step 3: After a preset time, control the microelectromechanical gyroscope to operate in full-angle precession mode, so that the mode angle of the microelectromechanical gyroscope changes from... Precession And identify the mode angle from Precession Damping angle during the process Then control the microelectromechanical gyroscope to operate at a mode angle of... Under the force balance mode; Step 4: After a preset time, control the microelectromechanical gyroscope to operate in full-angle precession mode, so that the mode angle of the microelectromechanical gyroscope changes from... Precession And identify the mode angle from Precession Damping angle during the process Then control the microelectromechanical gyroscope to operate at a mode angle of... Under the force balance mode; Step 5: Repeat steps 3 to 4 to achieve the identification and self-calibration of the damping axis of the microelectromechanical gyroscope, thereby improving the zero-bias stability of the microelectromechanical gyroscope.

2. The method for real-time suppression of zero-bias drift and improvement of zero-bias stability of a symmetrical gyroscope according to claim 1, characterized in that, During the mode shape precession process in steps 2 to 4, the damping angle is obtained by fitting the curve of the driving force or the in-phase balancing force of the gyroscope's short axis in the full-angle self-precession mode as a function of the mode shape angle.

3. The method for real-time suppression of zero-bias drift and improvement of zero-bias stability of a symmetrical gyroscope according to claim 1, characterized in that, In steps 1 to 5, the virtual rotation of the microelectromechanical gyroscope's working mode is achieved through a rotation control module or a virtual rotation closed-loop measurement and control circuit.

4. The method for real-time suppression of zero-bias drift and improvement of zero-bias stability of a symmetrical gyroscope according to any one of claims 1 to 3, characterized in that, A timing controller is used to periodically switch the operating modes of the microelectromechanical gyroscope.

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