A method for compensating the gain error of a hemispherical resonant gyroscope control circuit

Abstract

This invention belongs to the field of inertial measurement technology and discloses a method for gain error compensation in a hemispherical resonant gyroscope control circuit. A carrier signal with frequency ω2 is applied to the gyroscope signal, where ω2 is far from the resonant frequency ω1 of the resonator, thereby achieving estimation and compensation of the gain error Δk at the resonant frequency ω1. This invention can achieve real-time estimation of gain asymmetry error without affecting the normal operation of the hemispherical resonant gyroscope, improving the accuracy of hemispherical resonant gyroscope signal processing and full-angle control.

Description

Technical Field

[0001] This invention belongs to the field of inertial measurement technology, specifically relating to a method for compensating for gain error in a hemispherical resonant gyroscope control circuit. Background Technology

[0002] In modern warfare, new-generation weapons and equipment are required to possess precision strike, rapid response, and strong anti-jamming capabilities. Gyroscopes are the core components of inertial navigation systems and are a key technology for improving the battlefield adaptability, survivability, and collaborative combat capabilities of weapon systems.

[0003] The rate integral hemispherical resonator gyroscope is a solid-state wave gyroscope that uses the precession of the standing wave along the circumferential direction of a hemispherical resonator to sense the angular motion of the base. It employs a two-piece structure of a resonator and a planar electrode, offering high precision while being structurally simpler and more suitable for low-cost mass production. It can directly measure the rotation angle of the carrier, and the precession coefficient of the standing wave is determined solely by the resonator structure, exhibiting excellent scaling factor stability. It possesses unique advantages such as high precision, radiation resistance, low power consumption, small size, high reliability, long lifespan, and maintenance-free operation throughout its lifespan, meeting the development requirements of next-generation weaponry.

[0004] Signal detection in a hemispherical resonator gyroscope is achieved through the current signal generated by the change in distance between the lip of the sensitive resonator and the plate electrode. By acquiring signals at 45-degree intervals on the resonator and using a traditional IQ demodulation algorithm, information such as vibration amplitude, quadrature amplitude, and phase can be extracted. Because the resonator's vibration amplitude is small, typically tens of micrometers, the current signal generated by the plate electrode is extremely weak and susceptible to noise. Therefore, signal conditioning and amplification circuits are required for signal processing. The signal acquisition circuits at 45-degree intervals on the resonator are defined as X-channel and Y-channel circuits, respectively. To ensure accurate extraction of the vibration signal, the X and Y channels must have identical circuit characteristics. However, due to differences in the performance of electronic components such as capacitors, resistors, operational amplifiers, and switches in the signal acquisition circuit, the gains of the X and Y channels are asymmetrical. This means that when the same signal passes through the two channels, the sampled signal amplitudes will differ. This difference leads to errors in the information obtained through IQ demodulation of the vibration signal. These errors are further fed back to the resonator through control loops such as amplitude stabilization, quadrature, and frequency tracking, thus causing gyroscope output errors. Summary of the Invention

[0005] This invention addresses the problem of gyroscope output error caused by asymmetric X and Y channel gains. It proposes a method for excitation and identification of asymmetric channel gain error in the control circuit of a hemispherical resonant gyroscope, thereby improving the signal processing and control accuracy of the hemispherical resonant gyroscope in full-angle operating mode.

[0006] To achieve the objective of this invention, the present invention provides a gain error compensation method for a hemispherical resonant gyroscope control circuit, and the technical solution is as follows:

[0007] A carrier signal with frequency ω2 is applied to the gyroscope signal. The frequency ω2 is far away from the resonant frequency ω1 of the harmonic oscillator (ω2≥3ω1), so as to realize the estimation and compensation of the gain error Δk at the resonant frequency ω1.

[0008] Furthermore, the gain error Δk at the resonant frequency is estimated using the following formula:

[0009]

[0010] Where, k x (ω1), k y (ω1) represents the X and Y channel gains at the resonant frequency ω1, respectively, k x (ω2), k y (ω2) are the X and Y channel gains at the resonant frequency ω2, respectively, and the function H(·) is obtained by taking the circuit's transfer function.

[0011] Furthermore, when the circuit is complex and the function H(·) is difficult to obtain directly, multiple carrier signals of different frequencies are applied to obtain the gain at multiple frequency points and establish a gain estimation model, thereby realizing real-time estimation and compensation of the gain asymmetry error at the resonant frequency ω1.

[0012] The beneficial effects of this invention are that, based on the amplitude-frequency characteristics of the hemispherical resonant gyroscope control circuit and the vibration signal characteristics of the hemispherical resonant gyroscope, a carrier signal of a specific frequency is designed to excite and identify the gain asymmetry error of the control circuit. The algorithm is simple in principle and easy to implement, and can realize real-time estimation of gain asymmetry error without affecting the normal operation of the hemispherical resonant gyroscope, thereby improving the signal calculation and full-angle control accuracy of the hemispherical resonant gyroscope. Detailed Implementation

[0013] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. 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 them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0014] The core of this invention is to design a carrier wave of a specific frequency to excite and identify the gain asymmetry error of the X / Y channel based on the amplitude-frequency characteristics of the hemispherical resonant gyroscope control circuit and the characteristics of the gyroscope vibration signal.

[0015] 1. Analysis of the impact of gain asymmetry error

[0016] Under ideal conditions, the sampled signals for the X and Y channels are:

[0017]

[0018] In the formula, a represents the vibration amplitude at the antinode, q represents the vibration amplitude at the node, ω1 represents the resonant frequency of the harmonic oscillator, and θ represents the azimuth angle of the standing wave. When the X and Y channel gains are asymmetrical and the X channel gain is used as the reference, the X and Y channel gains can be obtained as k. x =1, k y = 1 + Δk, where Δk is the gain error, and the sampled signals for the X and Y channels are:

[0019]

[0020] Demodulating the above equation using the IQ demodulation algorithm yields:

[0021]

[0022] In the formula, LPF represents low-pass filtering, ω ref Indicates the reference signal frequency. This represents the phase difference between the reference signal and the vibration signal. As shown in the equation above, the asymmetry in the gains of the X and Y channels leads to demodulation errors in the gyroscope vibration signal. This demodulation error is further fed back to the gyroscope through the amplitude stabilization, quadrature, and frequency tracking loops, resulting in decreased control accuracy and affecting the gyroscope's output accuracy.

[0023] 2. Error Excitation Carrier Design

[0024] The amplitude of a signal propagating in the gyroscope control circuit is also affected by the gain asymmetry error of the X and Y channels. Assuming there exists a sinusoidal signal with amplitude b and frequency ω², when this signal is sampled simultaneously by the X and Y channels of the gyroscope control circuit, we can obtain...

[0025]

[0026] The above equation is then applied using the IQ demodulation method to demodulate the X and Y channel signals respectively:

[0027]

[0028]

[0029] The gain errors of the X and Y channels can be obtained from the above formula:

[0030]

[0031]

[0032] The gain asymmetry error of the X and Y channels at any frequency can be calculated using the above formula. If the gain asymmetry error of the X and Y channels in the gyroscope control circuit remains unchanged, this error can be calibrated in advance using the above method, and then compensated to the control modulation signal during normal gyroscope operation to eliminate the error. However, the gain asymmetry error of the X and Y channels is affected not only by the resonant signal frequency but also by external environmental factors such as temperature, requiring real-time observation and compensation. Analysis of the circuit's amplitude-frequency characteristics reveals the following relationship between the gains at any two frequencies:

[0033] k x (ω1)=H(k x (ω2))

[0034] k y (ω1)=H(k y (ω2))

[0035] Therefore, the gain at the resonant frequency ω1 can be obtained by using the channel gain at any frequency ω2. When the gyroscope is in normal operating condition, a carrier signal with a known frequency can be applied to the gyroscope signal, which can be expressed as:

[0036] I in = a sin(ω1t) + b sin(ω2t)

[0037] When a reference signal is used for IQ demodulation, the following can be obtained:

[0038]

[0039]

[0040] Where, ω ref This is the reference signal frequency.

[0041] As shown in the above equation, the accuracy of identifying the resonator vibration parameters is affected by the carrier signal frequency and the performance of the low-pass filter. When the carrier signal frequency ω2 is close to the resonant frequency ω1, eliminating the influence of the carrier signal on the vibration parameter calculation places high demands on the design of the low-pass filter. The cutoff frequency of the low-pass filter needs to be between ω1 and ω2, and it needs to have a high attenuation factor. Therefore, to ensure filtering accuracy, the carrier signal frequency needs to be set far away from the resonator resonant frequency, ω2≥3ω1. At this time, when using the carrier signal itself for IQ demodulation, the following can be obtained:

[0042]

[0043]

[0044] This ensures that the vibration parameters of the harmonic oscillator are calculated normally, while simultaneously enabling real-time calculation of the gain of the gyroscope control circuit at frequency ω2.

[0045] 3. Error Identification and Compensation

[0046] Based on the gain estimation method for the gyroscope control circuit described above, real-time gain calculation at frequency ω2 can be achieved by designing a reasonable carrier signal. Furthermore, this can be further achieved through a function...

[0047]

[0048] This allows for the estimation and compensation of gain asymmetry error at the current resonant frequency. The function H(·) can be obtained by taking the circuit's transfer function. When the circuit is complex and the function H(·) is difficult to obtain directly, the gain asymmetry error at the resonant frequency ω1 can be estimated and compensated in real time by taking the gain at multiple frequency points and establishing a gain estimation model.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for compensating the gain error of a hemispherical resonant gyroscope control circuit, characterized in that, The gain error compensation method for the hemispherical resonant gyroscope control circuit includes: There exists an amplitude of b and a frequency of A sinusoidal signal can be obtained by simultaneously sampling the X and Y channels of the gyroscope control circuit. ， The above equation is then applied using the IQ demodulation method to demodulate the X and Y channel signals respectively: ， The gain errors of the X and Y channels can be obtained from the above formula: ， By analyzing the amplitude-frequency characteristics of the circuit, the following relationship can be obtained regarding the gain at any two frequencies: ， Therefore, it can be done at any frequency point Determine the resonant frequency from the channel gain at that point. Gain at that point. When the gyroscope is in normal operating condition, a carrier signal with a known frequency can be applied to the gyroscope signal, which can be expressed as: ， When a reference signal is used for IQ demodulation, the following can be obtained: ， in, The reference signal frequency; Apply frequency to the gyroscope signal The carrier signal, the frequency Far from the resonant frequency of the harmonic oscillator And satisfy: To achieve the resonant frequency Gain error at Estimation and Compensation: The gain error estimate at the resonant frequency is calculated using the following formula. ， in, , These are the resonant frequencies. X and Y channel gain at the location, , These are the resonant frequencies. X and Y channel gain at the location, function It is obtained by determining the transfer function of the circuit.

2. The gain error compensation method for a hemispherical resonant gyroscope control circuit according to claim 1, characterized in that, When the circuit is complex, the function When it is difficult to obtain the resonant frequency directly, multiple carrier signals of different frequencies are applied to calculate the gain at multiple frequency points, and an estimation model for the gain is established to realize the resonant frequency. Real-time estimation and compensation of gain error at the location.

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