A charge amplifier-based resonator gyroscope feedthrough error compensation device and method

Abstract

This invention discloses a resonant gyroscope feedthrough error compensation device and method based on a charge amplifier. First, under normal operating conditions, a signal with a fixed amplitude, far from the gyroscope's resonant frequency, is differentially injected into the driving electrode and force feedback electrode, respectively, to ensure that the injected signal does not cause vibration of the resonator. The charge amplifier simultaneously amplifies the feedthrough signal and the gyroscope vibration signal, and after sampling, sends them to the demodulation module. Then, the demodulation module demodulates the injected feedthrough signal to obtain the feedthrough gain from the driving electrode and force feedback electrode to the driving detection electrode and detection electrode, respectively. Finally, the feedthrough error can be calculated based on the amplitude of the applied driving signal and the amplitude of the force feedback signal, and the feedthrough error is compensated accordingly. This invention compensates for the feedthrough error in real time without affecting the normal operation of the gyroscope, thereby reducing the output bias and noise of the resonant gyroscope and improving the stability of the system.

Description

Technical Field

[0001] This invention belongs to the field of resonant gyroscope technology, specifically relating to a resonant gyroscope feedthrough error compensation device and method based on a charge amplifier. Background Technology

[0002] Resonant gyroscopes, commonly used in the field of navigation, include silicon micro dual-mass gyroscopes, silicon micro quad-mass gyroscopes, and silicon micro ring gyroscopes. They all use the Coriolis effect to detect input angular velocity. Due to their advantages such as small size, light weight, high reliability, and mass production capability, they are widely used in marine inertial navigation systems, aviation inertial navigation systems, weapon inertial navigation systems, and space inertial navigation systems.

[0003] Feedthrough effect is a common source of error in resonant gyroscopes, affecting the gyroscope's output bias and noise level. It occurs because there is a capacitive coupling channel between the excitation and readout electrodes inside the resonant gyroscope. The applied drive and force feedback signals are directly coupled to the drive and detection ports through this capacitor, superimposing with the resonant gyroscope's vibration signal, resulting in a significant error. This affects the control system's ability to distinguish valid signals and the system's stability. Summary of the Invention

[0004] To address the aforementioned issues, this invention discloses a resonant gyroscope feedthrough error compensation device and method based on a charge amplifier. This device compensates for the feedthrough error in real time without affecting the normal operation of the gyroscope, thereby reducing the output bias and noise of the resonant gyroscope and improving system stability.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A resonant gyroscope feedthrough error compensation device based on a charge amplifier includes a charge amplifier and a demodulation module. During normal operation of the gyroscope, a signal with a fixed amplitude and far from the gyroscope's resonant frequency is differentially injected into the driving and force feedback electrodes, respectively. The charge amplifier simultaneously amplifies the feedthrough signal and the vibration signal, which are then sampled and sent to the demodulation module. The demodulation module demodulates the injected signals to obtain the feedthrough gains from the driving and force feedback electrodes to the driving and detection electrodes, respectively. Based on the phase and amplitude of the driving and force feedback signals, the corresponding feedthrough error is obtained. Online compensation is performed on the driving phase, driving amplitude, quadrature, and Coriolis demodulation values ​​to reduce system errors and improve the stability of the resonant gyroscope.

[0007] Furthermore, the signal frequency f injected into the driving electrode and the force feedback electrode respectively a f b All of these must be far from the gyroscope's resonant frequency, and the frequency difference must be much greater than the gyroscope's bandwidth, and f a ≠f bSince both the gyroscope driving mode and the detection mode can be equivalent to a second-order resonator, the response at frequencies far from the resonant frequency is negligible. Only the corresponding feedthrough signal can be detected on the driving and detection electrodes. In addition, the gain of the charge amplifier for the gyroscope capacitive feedthrough signal is only related to the ratio of the feedthrough capacitor to the feedback capacitor, and is independent of the signal frequency. Therefore, the feedthrough gain is consistent for signals of different frequencies.

[0008] Furthermore, the frequency f is used to drive the detection and readout from the detection electrode. a and f b The feedthrough signals are demodulated to obtain their amplitude information, thereby obtaining the feedthrough gain between the drive and force feedback electrodes and the drive detection and detection electrodes.

[0009] Furthermore, based on the gain of the controllable gain amplifier, the amplitude ratio of the applied drive and force feedback signals to the additional injection signal is obtained, thereby calculating the amplitude information of the corresponding feedthrough signal after demodulation. Then, based on the phase information of the feedthrough signal, online compensation is performed on the amplitude, phase, Coriolis and quadrature demodulation values ​​in the control loop.

[0010] The beneficial effects of this invention are:

[0011] (1) When driving and force feedback signals are applied to the resonant gyroscope, the charge amplifier can detect not only vibration displacement information, but also feedthrough error signal. This invention compensates for the feedthrough error caused by driving and force feedback signals by demodulating the additionally injected feedthrough signal. This does not affect the normal operation of the resonant gyroscope, and can also reduce the impact of feedthrough error on the system.

[0012] (2) Compared with ordinary feedthrough error compensation, the present invention achieves real-time feedthrough error compensation by obtaining the feedthrough error magnitude online. Attached Figure Description

[0013] Figure 1 This is a block diagram illustrating the system implementation of the present invention.

[0014] Figure 2 This is a block diagram of the demodulation module I of the present invention.

[0015] Figure 3 This is a block diagram of the demodulation module II of the present invention.

[0016] Figure 4 This is a block diagram of the demodulation module III of the present invention. Detailed Implementation

[0017] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0018] like Figure 1 As shown, the resonant gyroscope feedthrough error compensation method based on charge amplifier of the present invention includes the following steps:

[0019] Step 1: When the resonant gyroscope is working normally, the drive detection electrode and the output signal of the detection electrode pass through the charge amplifier to complete the C / V conversion, and then pass through the demodulation module I (such as...). Figure 2 (As shown) and the PID controller output the drive phase, drive amplitude, quadrature and Coriolis values ​​respectively;

[0020] Step 2: In the orthogonal and Coriolis force feedback control mode, the output of the first PID is sent to the phase-locked loop I to control the drive signal frequency ω. d The outputs of the second, third, and fourth PID controllers are fed into the controllable gain amplifier module, which amplifies the AC signal output from the phase-locked loop I and applies it to the gyroscope drive and force feedback electrodes to achieve control of drive amplitude, quadrature, and Coriolis effect.

[0021] Step 3: In the improved section, two AC signals far from the gyroscope's resonant frequency are output through phase-locked loop II and differentially injected into the gyroscope drive electrode and force feedback electrode, respectively. The charge amplifier simultaneously amplifies the gyroscope vibration signal and the feedthrough signal, and after amplification, they are sent to demodulation module II and demodulation module III to obtain the gyroscope's feedthrough gain.

[0022] Step 4: Divide the amplitudes of the drive signal, Coriolis force feedback signal, and quadrature force feedback signal by the amplitudes of the signals injected into the drive and force feedback electrodes, respectively, and then multiply them by the feedthrough gain of the injected signal to obtain the feedthrough error to be compensated. Based on the phase information, compensate for the drive phase, drive amplitude, Coriolis and quadrature demodulation values ​​to achieve online feedthrough error compensation.

[0023] Step 1 is as follows:

[0024] like Figure 1 The diagram shown is a system block diagram of the present invention. The driving detection electrode and the detection electrode output capacitance detection signal are converted to a voltage signal V by a charge amplifier after C / V conversion. x and V y The signal is sent to demodulation module I, and the demodulation reference signal is a unit amplitude signal, such as... Figure 2 Demodulation is performed as shown to obtain the driving phase, driving amplitude, quadrature, and Coriolis information, i.e., s. x c x c y s y The demodulated signal is then sent to the PID control module.

[0025] Step 2 is as follows:

[0026] The control signal output by the PID controller is fed into the phase-locked loop I and the controllable gain amplifier respectively. The frequency of the output AC signal of the phase-locked loop I and the amplitude of the drive signal, orthogonal force feedback and Coriolis force feedback signals are adjusted in real time to make the resonant gyroscope drive mode oscillate at its resonant frequency with a steady amplitude, and to suppress the vibration of the gyroscope detection mode and keep it in a stationary state. The amplitude of the Coriolis force feedback signal reflects the magnitude of the input angular velocity.

[0027] Step 3 is as follows:

[0028] Due to the capacitive feedthrough effect within the mechanical structure of the resonant gyroscope, the gain of the charge amplifier for the feedthrough signal is... Among them, C ft C is the feedthrough capacitance value. f The value is the feedback capacitor of the charge amplifier. It can be seen that the gain of the charge amplifier for the capacitive feedthrough signal is independent of the signal frequency. In the improved section, two signals far from the gyroscope's resonant frequency are output through phase-locked loop II. These signals are superimposed on the drive and force feedback signals, respectively, and then differentially injected into the gyroscope drive and force feedback electrodes. Based on the transfer functions of the gyroscope drive mode and detection mode:

[0029]

[0030] Where m is the modal mass, ω is the modal resonant frequency, and Q is the modal quality factor.

[0031] The response of the injected signal to the gyroscope's mechanical structure is negligible;

[0032] Taking the driving circuit as an example, when the driving mode is in a resonant state, charge amplifier II only amplifies the feedthrough signal Asin(ω) corresponding to the injected signal. a t), Bsin(ω) b t), the gyroscope vibration signal A controlled by the drive signal. x cos(ω d t) and the corresponding feedthrough signal Msin(ω) d t), the output signal of charge amplifier II is sent to demodulation module II, and the demodulation reference signal is unit amplitude, i.e., sin(ω a t) and sin(ω b Taking multiplication demodulation as an example, after the charge amplifier is multiplied by the reference signal, the output signals are as follows:

[0033]

[0034]

[0035] Due to ω a ω b and ω dThe frequency difference between them is relatively large. After multiplication, the signal is low-pass filtered to obtain the DC component, with amplitudes of [missing values].

[0036] Similarly, the output of charge amplifier I is processed by demodulation module II to obtain the amplitude information s of the injected feedthrough signal. a1 s b1 Among them, s a1 s b1 s a2 s b2 These respectively reflect the feedthrough gain from the force feedback electrode, the driving electrode to the detection electrode, and the feedthrough gain to the driving and detection electrodes.

[0037] Step 4 is as follows:

[0038] Divide the amplitudes of the drive signal, orthogonal force feedback signal, and Coriolis force feedback signal by the amplitude of the injected signal, and then multiply by the amplitude of the injected feedthrough signal obtained in step 3 to obtain the feedthrough error values ​​caused by the drive signal and force feedback signal. According to the phase information of each signal, the feedthrough of the drive signal and Coriolis force feedback signal causes errors in the phase demodulation value of the drive circuit and the Coriolis demodulation value of the force feedback circuit. The feedthrough of the orthogonal force feedback signal causes errors in the amplitude demodulation value of the drive circuit and the orthogonal demodulation value of the force feedback circuit. After compensating for each error value online in sequence, the zero bias of the system output can be effectively reduced and the system stability can be improved.

[0039] It should be noted that the above content merely illustrates the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. For those skilled in the art, various improvements and modifications can be made without departing from the principle of the present invention, and all such improvements and modifications fall within the scope of protection of the claims of the present invention.

Claims

1. A charge amplifier based resonator gyroscope feedthrough error compensation device, characterized by: The system includes a charge amplifier and a demodulation module. During normal operation, a signal with a fixed amplitude, far from the gyroscope's resonant frequency, is differentially injected into the drive and force feedback electrodes, respectively, and there is also a frequency difference between them. The charge amplifier simultaneously amplifies the feedthrough signal and the vibration signal, which are then sampled and sent to the demodulation module. The demodulation module demodulates the injected signals, and the demodulated value is divided by the amplitude of the injected signal to obtain the feedthrough gain from the drive electrode and the force feedback electrode to the drive detection electrode and the detection electrode, respectively. The amplitudes of the drive signal, the Coriolis force feedback signal, and the orthogonal force feedback signal are multiplied by the feedthrough gain of the injected signal to obtain the feedthrough error to be compensated. In the resonant gyroscope control system, the feedthrough of the drive signal and the Coriolis force feedback signal introduces errors in the phase of the drive circuit and the Coriolis demodulation value of the force feedback circuit. The feedthrough of the orthogonal force feedback signal introduces errors in the amplitude of the drive circuit and the orthogonal demodulation value of the force feedback circuit. Therefore, online compensation can be achieved by injecting additional signals.

2. The charge amplifier based resonator gyro feedthrough error compensation apparatus of claim 1, wherein, The resonant gyroscope has a capacitive feedthrough, and the interface circuit is a charge amplifier. The feedthrough gain is obtained by utilizing the characteristic that the amplitude and phase of the detected feedthrough signal are independent of the frequency.

3. A compensation method using the charge amplifier based resonator gyroscope feedthrough error compensation device of claim 1, characterized in that: Includes the following steps: Step 1: When the resonant gyroscope is working normally, the drive detection electrode and the output signal of the detection electrode are converted by the charge amplifier, and then the drive phase, drive amplitude, quadrature and Coriolis demodulation values ​​are output after passing through the demodulation module I and the PID controller respectively. Step 2: In the orthogonal and Coriolis force feedback control mode, the output of the first PID controller is sent to the phase-locked loop I to control the drive signal frequency. The outputs of the second, third, and fourth PID controllers are fed into a controllable gain amplifier to adjust its gain, thereby amplifying the AC signal output from the phase-locked loop I and applying it to the gyroscope drive and force feedback electrodes to achieve control of the drive amplitude, quadrature, and Coriolis effect. Step 3: In the improved part, two AC signals far from the gyroscope resonant frequency are output through phase-locked loop II and differentially injected into the gyroscope drive electrode and force feedback electrode, respectively. The charge amplifier simultaneously amplifies the gyroscope vibration signal and the feedthrough signal. After amplification, the signals are sent to demodulation module II and demodulation module III, and then divided by the amplitude of the injected signal to obtain the feedthrough gain of the gyroscope. Step 4: Multiply the amplitudes of the drive signal, Coriolis force feedback signal, and orthogonal force feedback signal by the feedthrough gain of the injected signal to obtain the feedthrough error to be compensated. In the resonant gyroscope control system, the feedthrough of the drive signal and the Coriolis force feedback signal introduces errors in the phase of the drive loop and the Coriolis demodulation value of the force feedback loop. The feedthrough of the orthogonal force feedback signal introduces errors in the amplitude of the drive loop and the orthogonal demodulation value of the force feedback loop. Therefore, the feedthrough gain from the drive electrode to the drive detection electrode and the detection electrode, and the feedthrough gain from the force feedback electrode to the drive detection electrode and the detection electrode obtained by the injected signal can be compensated online.

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