Method and system for identifying and inhibiting nonlinear error of hemispherical resonator gyroscope

Abstract

The invention relates to the technical field of intelligent instruments and meters, in particular to a method and system for identifying and inhibiting nonlinear errors of a hemispherical resonator gyro, and the method comprises the following steps: operating the hemispherical resonator gyro in a full-angle mode; setting an initial nonlinear compensation matrix, an initial amplitude gap ratio and a traversal rule of the amplitude gap ratio; the method comprises the following steps: acquiring an amplitude differential signal in the running process of the hemispherical resonator gyroscope, identifying an eighth harmonic amplitude in the amplitude differential signal by using an RLS algorithm filter, and finding out an amplitude gap ratio corresponding to the lowest harmonic amplitude; and adjusting the initial nonlinear compensation matrix based on the amplitude gap ratio to obtain a nonlinear compensation matrix, and compensating a demodulation signal based on the nonlinear compensation matrix to complete identification and compensation of the nonlinear error of the hemispherical resonator gyroscope. The method can be used for accurately identifying and calibrating the nonlinear error of the electrode in the hemispherical resonator gyroscope.

Description

Technical Field

[0001] The present invention relates to the technical field of intelligent instruments and meters, and in particular to a method and system for identifying and suppressing nonlinear errors of a hemispherical resonant gyroscope. Background Art

[0002] During the detection and control process of the hemispherical resonant gyroscope, the tiny capacitor with a variable spacing formed by the gyroscope detection electrode and the hemispherical resonator metal film layer will introduce detection nonlinear errors into the system, which is specifically manifested as the eighth harmonic error related to the precession angle in the amplitude signal and the angular velocity signal. This will directly affect important indicators such as the detection accuracy of the gyroscope's precession angular velocity and zero bias stability.

[0003] However, in existing research, there is a lack of accurate identification and calibration of the detection nonlinear error in the hemispherical resonant gyroscope. In addition, the existing detection nonlinear compensation technology is limited by the detection preamplifier circuit structure and is not applicable in other amplifier circuit environments. To this end, the present invention proposes a method and system for identifying and suppressing the nonlinear error of the hemispherical resonant gyroscope. Summary of the invention

[0004] The purpose of the present invention is to overcome the problem that the nonlinear error in the hemispherical resonant gyroscope system is difficult to accurately identify and suppress during actual operation, and a method and system for identifying and suppressing the nonlinear error of the hemispherical resonant gyroscope is provided by using a recursive least squares algorithm.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] A method for identifying and suppressing nonlinear errors of a hemispherical resonant gyroscope, comprising:

[0007] Run the hemispherical resonant gyro in full-angle mode;

[0008] Setting the initial nonlinear compensation matrix, the initial amplitude-gap ratio and the traversal rule of the amplitude-gap ratio;

[0009] During the operation of the hemispherical resonant gyroscope, an amplitude differential signal is collected, an eighth harmonic amplitude in the amplitude differential signal is identified using an RLS algorithm filter, and an amplitude gap ratio corresponding to the lowest harmonic amplitude is found;

[0010] The initial nonlinear compensation matrix is ​​adjusted based on the amplitude gap ratio to obtain a nonlinear compensation matrix, and the demodulated signal is compensated based on the nonlinear compensation matrix to complete the identification and compensation of the nonlinear error of the hemispherical resonator gyroscope.

[0011] Optionally, the amplitude differential signal is:

[0012]

[0013] In the formula, is the differential signal of the amplitude component, a is the amplitude component, θ is the precession angle, τ is the damping decay time constant, A1 and A2 are the damping anisotropy related error coefficients, A3 and A4 are the electrode nonlinearity related error coefficients.

[0014] Optionally, identifying the eighth harmonic amplitude in the amplitude differential signal by using an RLS algorithm filter includes:

[0015] S1. Selecting a state matrix based on the amplitude differential signal, initializing a covariance matrix, a state transfer matrix and a forgetting factor;

[0016] S2, multiplying the state signal in the state matrix by the corresponding state transfer matrix to obtain an output signal;

[0017] S3, obtaining an error signal by comparing the output signal with the actual measurement signal, and updating the state matrix based on the error signal, repeating S2-S3 until the RLS algorithm converges, and obtaining a final state matrix;

[0018] S4. Calculate the eighth harmonic amplitude in the amplitude differential signal based on the final state matrix.

[0019] Optionally, the eighth harmonic amplitude is:

[0020]

[0021] In the formula, A n_8θ = is the eighth harmonic amplitude, A3(k) and A4(k) are the discretized electrode nonlinear error coefficients, and k is the number of discrete points.

[0022] Optionally, the nonlinear compensation matrix adjusted based on the amplitude-gap ratio is:

[0023]

[0024] In the formula, r e is the amplitude gap ratio corresponding to the lowest harmonic amplitude, and θ is the precession angle.

[0025] Optionally, the demodulated signal after compensation based on the nonlinear compensation matrix is:

[0026]

[0027] Wherein, cx', cy', sx', sy' are demodulated signals after compensation based on the nonlinear compensation matrix, and cx, cy, sx, sy are demodulated signals.

[0028] To further achieve the above object, the present invention also provides a system for identifying and suppressing nonlinear errors of a hemispherical resonant gyroscope, comprising:

[0029] An operation setting module, used to set the operation mode of the hemispherical resonant gyroscope, wherein the operation mode is a full-angle mode;

[0030] An initial parameter setting module, used to set an initial nonlinear compensation matrix, an initial amplitude-gap ratio, and an ergodic rule for the amplitude-gap ratio;

[0031] An operation data acquisition module is used to collect amplitude differential signals during the operation of the hemispherical resonant gyroscope;

[0032] An error identification module is used to identify the eighth harmonic amplitude in the amplitude differential signal by using an RLS algorithm filter, and find the amplitude gap ratio corresponding to the lowest harmonic amplitude;

[0033] The error compensation module is used to adjust the initial nonlinear compensation matrix based on the amplitude gap ratio, obtain the nonlinear compensation matrix, and compensate the demodulated signal based on the nonlinear compensation matrix.

[0034] The beneficial effects of the present invention are:

[0035] The method and system proposed in the present invention can accurately identify and calibrate the electrode nonlinear errors existing in the hemispherical resonant gyroscope. In addition, the existing detection nonlinear compensation technology is limited by the detection channel preamplifier circuit structure and does not have strong applicability under different control circuit environments. The function of the present invention is easy to implement, and there is no need to adjust the circuit and hardware modules. The overall identification and compensation are completed by the program. In addition, the present invention accurately completes the identification of the amplitude gap ratio, and the compensation matrix based on the amplitude gap ratio is highly applicable and does not rely on the control system environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 A flow chart of a method for identifying and suppressing nonlinear errors of a hemispherical resonant gyroscope according to an embodiment of the present invention;

[0038] Figure 2 is the differential of the amplitude component of the embodiment of the present invention The corresponding relationship curve diagram when θ=0~2π changes;

[0039] Figure 3 4 is a schematic diagram of the nonlinear behavior of the hemispherical resonant gyroscope at the detection electrode according to an embodiment of the present invention. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] This embodiment provides a method for identifying and suppressing a nonlinear error of a hemispherical resonant gyroscope, including:

[0043] Run the hemispherical resonant gyro in full-angle mode;

[0044] Setting the initial nonlinear compensation matrix, the initial amplitude-gap ratio and the traversal rule of the amplitude-gap ratio;

[0045] The amplitude differential signal is collected during the operation of the hemispherical resonant gyroscope, and the eighth harmonic amplitude in the amplitude differential signal is identified using the RLS algorithm filter, and the amplitude gap ratio corresponding to the lowest harmonic amplitude is found;

[0046] The initial nonlinear compensation matrix is ​​adjusted based on the amplitude gap ratio, the nonlinear compensation matrix is ​​obtained, and the demodulated signal is compensated based on the nonlinear compensation matrix to complete the identification and compensation of the nonlinear error of the hemispherical resonant gyroscope.

[0047] Specifically, this embodiment can accurately identify and calibrate the electrode nonlinear error in the hemispherical resonant gyroscope. In addition, the existing detection nonlinear compensation technology is limited by the detection channel preamplifier circuit structure and does not have strong applicability in different control circuit environments. The function of this embodiment is easy to implement, and there is no need to adjust the circuit and hardware module. The overall identification and compensation are completed by the program.

[0048] Different preamplifier circuits and drive voltages make it difficult to accurately estimate the amplitude-gap ratio r of the hemispherical resonant gyroscope. Even if the initial spacing d0 of the plates is determined, it is still very difficult to estimate the small vibration displacement x of the resonator. Therefore, a method is needed to effectively and accurately estimate the amplitude-gap ratio r, so as to complete the calculation of the electrode nonlinear error compensation matrix. Figure 1-Figure 3 A method for identifying and suppressing the nonlinear error of a hemispherical resonant gyroscope proposed in this embodiment is described in detail, specifically including:

[0049] Step 1: Mount the HRG on a single-axis rate stage and operate the HRG in full-angle mode.

[0050] Step 2: Set the initial nonlinear compensation matrix And set a compensation strategy, that is, use the initial nonlinear error compensation matrix to multiply the real-time demodulated signals cx, cy, sx, sy, and set the initial amplitude gap ratio a / d0=r to 0. In fact, the demodulated signal is not compensated at this time.

[0051] Step 3: Use the RLS algorithm filter to differentiate the acquired amplitude signal The eighth harmonic error term amplitude in is used for identification. At the same time, the amplitude gap ratio r is adjusted in the compensation program to be accumulated every 0.001 between 0 and 0.1, and the traversal interval is adjusted based on the convergence time of the RLS algorithm. Further sacrificing the algorithm traversal speed can improve the identification accuracy of the amplitude gap ratio. For example, the traversal interval is reduced to 0.0005 to improve the identification accuracy of the final amplitude gap ratio.

[0052] Step 4: Compare the eighth harmonic amplitudes identified by the RLS algorithm during the entire amplitude-gap ratio traversal process. The lowest value is the actual amplitude-gap ratio r of the corresponding hemispherical resonant gyro system. e ; Finally, based on the actual amplitude gap ratio r of the system e The nonlinear error compensation matrix in step 2 is adjusted to achieve compensation for the nonlinear error of the electrode.

[0053] Furthermore, in step 3, the amplitude differential signal The definition and representation are as follows:

[0054] Differentiation of amplitude components based on the traditional elliptical parameter equation of hemispherical resonant gyroscope The expression takes into account the electrode nonlinear error. Based on existing related research, it is known that this nonlinear error is mainly caused by the non-speed coupling term A n1 sin8(θ+θ n1 ) and the speed coupling term [A n2 sin8(θ+θ n2 )]γΩ, the elliptic parameter equation of the amplitude component affected by the electrode nonlinearity is:

[0055]

[0056] Among them, θ is the precession angle, a is the amplitude component, q is the orthogonal component, γ is the precession factor, Ω is the external speed of the gyroscope, With θ τ are the damping anisotropy and the damping misalignment angle, Δω and θ respectively ωare stiffness anisotropy and stiffness misalignment angle, A n1 With A n2 is the eighth harmonic amplitude caused by the electrode nonlinear error, θ n1 With θ n2 is the electrode nonlinear phase shift. Orthogonal control makes the orthogonal component much smaller than the amplitude component. As shown in formula (1), the fourth harmonic in the amplitude differential signal comes from the influence of damping inhomogeneity and stiffness inhomogeneity, while the eighth harmonic component comes from the electrode nonlinear error. In addition, this error will also be affected by the coupling of the external speed. Simplifying and transforming formula (1), we can get:

[0057]

[0058] Simplify formula (2) and let:

[0059]

[0060] Then the differential equation of the amplitude component affected by the damping mismatch error and nonlinear error can be written as:

[0061]

[0062] From equation (4), we can draw the differential of the amplitude component: The relationship curve when θ=0~2π is as follows Figure 2 shown.

[0063] Furthermore, in step 3, the RLS algorithm filter is used to filter the acquired amplitude differential signal The specific process of identifying the amplitude of the eighth harmonic error term in includes:

[0064] S1. Select the state matrix based on the amplitude differential signal, initialize the covariance matrix, state transfer matrix and forgetting factor;

[0065] S2, multiplying the state signal in the state matrix by the corresponding state transfer matrix to obtain an output signal;

[0066] S3, obtaining an error signal by comparing the output signal with the actual measurement signal, and updating the state matrix based on the error signal, repeating S2-S3 until the RLS algorithm converges, and obtaining a final state matrix;

[0067] S4. Calculate the eighth harmonic amplitude in the amplitude differential signal based on the final state matrix.

[0068] Specifically, in this embodiment, an RLS algorithm filter is constructed to identify nonlinear errors, that is, to identify the eighth harmonic amplitude, and the steps are as follows:

[0069] (1) Select the state matrix

[0070] (2) Initialize the covariance matrix P(k) and the forgetting factor λ;

[0071] (3) Initialize the state transfer matrix H(k) = [1(k)cos4θ(k)sin4θ(k)sin8θ(k)cos8θ(k)] T ;

[0072] (4) Multiply the state signal in the state matrix by the corresponding state transfer matrix to obtain the output signal Y(k);

[0073] (5) Subtract the theoretical measurement value from the actual measurement value to obtain the error signal e(k) used to update the state matrix;

[0074] (6) The overall identification algorithm process is given by formula (5):

[0075]

[0076] Where K(k) is the gain vector used to update the state vector.

[0077] After the algorithm converges, the weight coefficient is used for further calculation, and the identification result of the nonlinear error, that is, the amplitude of the eighth harmonic error term, can be obtained as follows: After the nonlinear error is corrected and compensated, the amplitude component and the eighth harmonic error in the angular velocity signal can be made close to zero.

[0078] Furthermore, in step 4, based on the actual amplitude gap ratio r of the system e The nonlinear error compensation matrix in adjustment step 2 includes:

[0079] The detection electrode of the hemispherical resonant gyroscope and the metal film layer of the resonator form a capacitor with variable spacing, in which the detection end preamplifier circuit is composed of a charge amplifier. Figure 3 As shown. The differential voltage equation here is:

[0080] V Sx =V Sx+ -V Sx- ≈K s x+K sn x 3 (6)

[0081] Among them, K s K is the detection loop coefficient, sn To detect the nonlinear coefficient of the loop, V Sx is the detection voltage, V Sx+ is the detection voltage at the x+ electrode of the hemispherical resonant gyroscope, V Sx- is the detection voltage at the x-electrode of the hemispherical resonant gyroscope.

[0082] In full-angle mode, the demodulated signal affected by the nonlinear effect of the electrode is:

[0083]

[0084] Wherein, N1 is the demodulated signal gain coefficient, N2 is the nonlinear error gain coefficient in the demodulated signal, and δ is the system phase difference.

[0085] The nonlinear compensation matrix after adjustment based on the amplitude gap ratio is:

[0086]

[0087] In the formula, r e is the amplitude gap ratio corresponding to the lowest harmonic amplitude, and θ is the precession angle.

[0088] The demodulated signal after compensation based on the nonlinear compensation matrix is ​​as follows:

[0089]

[0090] Wherein, cx', cy', sx', sy' are demodulated signals after compensation based on the nonlinear compensation matrix, and cx, cy, sx, sy are demodulated signals.

[0091] To further optimize the technical solution, this embodiment further provides a system for identifying and suppressing the nonlinear error of a hemispherical resonator gyroscope, which is used to implement a method for identifying and suppressing the nonlinear error of a hemispherical resonator gyroscope, including:

[0092] An operation setting module, used to set the operation mode of the hemispherical resonant gyroscope, wherein the operation mode is a full-angle mode;

[0093] An initial parameter setting module, used to set an initial nonlinear compensation matrix, an initial amplitude-gap ratio, and an ergodic rule for the amplitude-gap ratio;

[0094] An operation data acquisition module is used to collect amplitude differential signals during the operation of the hemispherical resonant gyroscope;

[0095] An error identification module is used to identify the eighth harmonic amplitude in the amplitude differential signal by using an RLS algorithm filter, and find the amplitude gap ratio corresponding to the lowest harmonic amplitude;

[0096] The error compensation module is used to adjust the initial nonlinear compensation matrix based on the amplitude gap ratio, obtain the nonlinear compensation matrix, and compensate the demodulated signal based on the nonlinear compensation matrix.

[0097] The embodiments described above are only descriptions of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for identifying and suppressing nonlinear errors of a hemispherical resonant gyroscope, characterized in that: include: Run the hemispherical resonant gyro in full-angle mode; Setting the initial nonlinear compensation matrix, the initial amplitude-gap ratio and the traversal rule of the amplitude-gap ratio; During the operation of the hemispherical resonant gyroscope, an amplitude differential signal is collected, an eighth harmonic amplitude in the amplitude differential signal is identified using an RLS algorithm filter, and an amplitude gap ratio corresponding to the lowest harmonic amplitude is found; The initial nonlinear compensation matrix is ​​adjusted based on the amplitude gap ratio to obtain a nonlinear compensation matrix, and the demodulated signal is compensated based on the nonlinear compensation matrix to complete the identification and compensation of the nonlinear error of the hemispherical resonator gyroscope.

2. The method for identifying and suppressing the nonlinear error of a hemispherical resonant gyroscope according to claim 1, characterized in that: The amplitude differential signal is: In the formula, is the differential signal of the amplitude component, a is the amplitude component, θ is the precession angle, τ is the damping decay time constant, A1 and A2 are the damping anisotropy related error coefficients, A3 and A4 are the electrode nonlinearity related error coefficients.

3. The method for identifying and suppressing the nonlinear error of a hemispherical resonant gyroscope according to claim 1, characterized in that: Using the RLS algorithm filter to identify the eighth harmonic amplitude in the amplitude differential signal includes: S1. Selecting a state matrix based on the amplitude differential signal, initializing a covariance matrix, a state transfer matrix and a forgetting factor; S2, multiplying the state signal in the state matrix by the corresponding state transfer matrix to obtain an output signal; S3, obtaining an error signal by comparing the output signal with the actual measurement signal, and updating the state matrix based on the error signal, repeating S2-S3 until the RLS algorithm converges, and obtaining a final state matrix; S4. Calculate the eighth harmonic amplitude in the amplitude differential signal based on the final state matrix.

4. The method for identifying and suppressing nonlinear errors of a hemispherical resonant gyroscope according to claim 1, characterized in that: The eighth harmonic amplitude is: In the formula, A n_8θ = is the eighth harmonic amplitude, A3(k) and A4(k) are the discretized electrode nonlinear error coefficients, and k is the number of discrete points.

5. The method for identifying and suppressing the nonlinear error of a hemispherical resonant gyroscope according to claim 1, characterized in that: The nonlinear compensation matrix after adjustment based on the amplitude gap ratio is: In the formula, r e is the amplitude gap ratio corresponding to the lowest harmonic amplitude, and θ is the precession angle.

6. The method for identifying and suppressing the nonlinear error of a hemispherical resonant gyroscope according to claim 5, characterized in that: The demodulated signal after compensation based on the nonlinear compensation matrix is: Wherein, cx', cy', sx', sy' are demodulated signals after compensation based on the nonlinear compensation matrix, and cx, cy, sx, sy are demodulated signals.

7. A system for identifying and suppressing nonlinear errors of a hemispherical resonator gyroscope, used for implementing the method for identifying and suppressing nonlinear errors of a hemispherical resonator gyroscope according to any one of claims 1 to 6, characterized in that: include: An operation setting module, used to set the operation mode of the hemispherical resonant gyroscope, wherein the operation mode is a full-angle mode; An initial parameter setting module, used to set an initial nonlinear compensation matrix, an initial amplitude-gap ratio, and an ergodic rule for the amplitude-gap ratio; An operation data acquisition module is used to collect amplitude differential signals during the operation of the hemispherical resonant gyroscope; An error identification module is used to identify the eighth harmonic amplitude in the amplitude differential signal by using an RLS algorithm filter, and find the amplitude gap ratio corresponding to the lowest harmonic amplitude; The error compensation module is used to adjust the initial nonlinear compensation matrix based on the amplitude gap ratio, obtain the nonlinear compensation matrix, and compensate the demodulated signal based on the nonlinear compensation matrix.

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