Vibration signal reading system and vibration signal reading method for axisymmetric gyro based on rotating carrier wave

Abstract

This invention discloses a vibration signal readout method for an axisymmetric gyroscope based on a rotating carrier wave. Conventional vibration signal readout methods include time-division multiplexing readout and dual-frequency carrier readout. Time-division multiplexing achieves time-division multiplexing of the electrodes, but due to the limitations of unidirectional electrode technology, only half of the gyroscope's electrodes are in the readout state, and the asymmetrical circuit parameters of the two electrodes at the readout end introduce new errors. In dual-frequency carrier readout mode, two carrier waves of different frequencies are used to modulate the two electrodes as excitation signals, and readout is achieved through a single channel. However, the different carrier frequencies introduce gain matching problems at the readout end, leading to new errors. This solution employs a vibration signal readout method for an axisymmetric gyroscope based on a rotating carrier wave, specifically using a DDS digital generator to generate single-frequency carrier waves cosω. c The system incorporates the rotational decomposition of the carrier waves sinωt and cosωt. Furthermore, to address the limitation that a single-frequency carrier wave can only generate excitation signals with a fixed direction angle, rotational decomposition modulation is introduced to generate two signals, cosωt. c tcosωt and cosω c The initial carrier signal is modulated onto sine and cosine signals varying at frequency ω, respectively, and the x and y electrodes are excited. This is then read out by a single front-end amplifier circuit. This single front-end processing circuit also avoids the errors introduced by parameter asymmetry in two front-end processing circuits. Finally, a capacitor / voltage conversion circuit generates V. o To reconstruct the initial displacement signal from the readout signal after two modulations, two demodulation processes are used in demodulation: initial carrier demodulation and rotating carrier demodulation, which respectively filter out ω. c With frequency ω, the initial displacement voltage signal V is extracted. x and V y It not only avoids the errors caused by time-division multiplexing readout systems, but also avoids the gain adaptation problem caused by different frequency carriers at the readout end in dual-frequency carrier readout schemes.

Description

TECHNICAL FIELD

[0001] The application relates to a vibration signal reading method of an axisymmetric gyroscope based on a rotating carrier. BACKGROUND

[0002] The axisymmetric gyroscope is a kind of gyroscope with rotational symmetry, which performs well in stability and control characteristics and is widely used in navigation, attitude control and other fields. With the rapid development of the semiconductor industry, the axisymmetric gyroscope has a very broad development prospect due to its advantages of lightweight, low power consumption, low cost and high reliability. The axisymmetric gyroscope includes a hemispherical resonator gyroscope, a micro hemispherical resonator gyroscope, a ring gyroscope, a full-symmetry four-value quantity gyroscope and the like. The reading electrodes are arranged in a differential manner, that is, a pair of electrodes with a difference of 90 degrees in physical space are differential to each other. This mode greatly reduces the electrode eccentricity. In the front-end reading system of the control system, a differential capacitance detection mode is usually used. The conventional vibration signal reading method includes a time-sharing reading method and a double-frequency carrier reading method. In the time-sharing reading scheme, since the axisymmetric gyroscope cannot realize bidirectional electrodes, only half of the electrodes are usually in a reading state, and it is difficult to realize symmetric differential detection. At the same time, at the reading end, the reading signals of the x and y axes are processed by two independent signal processing circuits. Due to the parameter error of the circuits, the asymmetry of the two will also cause a large error in the reading signals. In the double-frequency carrier excitation scheme, two different frequency carriers are used to modulate two electrodes as excitation signals, and one channel is used for reading. Although the error is improved, the different frequency carriers at the reading end bring a new gain adaptation problem. SUMMARY

[0003] Technical problem: In the time-sharing reading scheme system, due to the process limitation of the axisymmetric gyroscope, the gyroscope cannot always be in a reading state, and the asymmetry of the two circuit parameters at the reading end will cause a large error in the reading signals. In the double-frequency carrier scheme, the gain adaptation problem caused by the introduction of two different frequency carriers.

[0004] Technical scheme: To solve the above technical problems, the application provides a vibration signal reading method of an axisymmetric gyroscope based on a rotating carrier. In the scheme, a DDS digital generator is used to generate an initial carrier and a rotating decomposition carrier, and the initial carrier is decomposed into x and y directions. Through the rotating carrier modulation, the initial carrier is modulated on the frequency of the rotating carrier, so that the carrier extraction at any angle can be realized. Then, the two axial carriers are used to excite the x and y electrodes of the gyroscope resonator. At this time, the gyroscope resonator structure is equivalent to a common capacitor plate. The weak change of the surface capacitance is picked up by a front-end amplification circuit and converted into a reading signal V by a capacitance / voltage conversion circuit. oAt this point, the read signal contains ω. d ,ω,ω c And combined harmonic components and higher-order harmonic components. ω d This is the gyroscope's resonant frequency, which is the frequency component that needs to be retained. The readout signal quantity V... o First, it passes through the initial carrier demodulation module to remove ω. c Its higher harmonic components are then demodulated separately in two paths by a rotating carrier demodulation module to remove ω and its higher harmonic components, while retaining frequency ω. d Finally, the original displacement signal V containing the x electrode was extracted. x and the original displacement signal V of the y electrode y .

[0005] To achieve the above objectives, the technical solution of the present invention is as follows: a vibration signal readout system for an axisymmetric gyroscope based on a rotating carrier wave, the system comprising a gyroscope resonator, a DDS initial carrier signal generator, a DDS rotating carrier cosine signal generator, a DDS rotating carrier sine signal generator, a front-end amplifier module, a capacitor / voltage conversion circuit module, an initial carrier demodulation module, and a rotating carrier demodulation module. First, the DDS initial carrier signal generator generates an initial carrier wave cosω. c Simultaneously, the DDS rotating carrier sine wave generator generates a rotating carrier sinωt along the y-axis, and the DDS rotating carrier cosωt generates a rotating carrier cosωt along the x-axis. Then, the initial carrier cosωt... c t is modulated with the rotating carriers cosωt of the x-axis and sinωt of the y-axis, respectively, with the initial carrier cosωt c Under the influence of a rotating carrier wave cosωt along the x-axis and a rotating carrier wave sinωt along the y-axis, a wave can be generated whose direction changes with the frequency ω of the rotating carrier wave. c The changing x-channel carrier signal cosω c The carrier signal cosωt of the t and y paths c tsinωt is used to generate excitation signals at arbitrary angles. Furthermore, the generated x-channel carrier signals cosωt... c The carrier signal cosωt of the t and y paths c tsinωt excites the x and y electrodes of the gyroscope resonator, respectively. The resulting change in surface capacitance is amplified by the front-end amplifier circuit and converted into a voltage V by the capacitor-to-voltage converter circuit. o At this time, it contains ω. d ,ω,ω c And combined harmonic components and higher-order harmonic components. Voltage quantity V o First, the initial carrier signal is demodulated by the initial carrier demodulation module, using the initial carrier cosω generated by the DDS initial carrier signal generator.c t as the demodulation signal, remove ω c and its harmonic components, and then pass through the rotating carrier demodulation module, and are demodulated in two paths respectively, the x-axis adopts the DDS rotating carrier cosine signal generator to generate the rotating carrier cosωt as the demodulation signal, remove ω d and its harmonic components, and retain the frequency ω d , and finally extract the original displacement signal V x of the x electrode and the original displacement signal V y of the y electrode. In the excitation carrier generation link, an initial carrier is generated by using a DDS carrier signal generator, which avoids the gain adaptation problem caused by the double-frequency carrier mode in the front-end amplifier circuit of the gyro resonator, and at the same time introduces a rotating carrier signal generator to generate the x-axis rotating carrier cosωt and the y-axis rotating carrier sinωt, which modulates the initial carrier signal cosω c t on the sine and cosine waveforms with a frequency of ω respectively, at this time, the x-axis carrier signal cosω c tcosωt and the y-axis carrier signal cosω c tsinωt can realize signal excitation at any angle. In addition, in the front-end amplifier module, a single amplifier circuit is used to extract the small capacitance change on the surface of the gyro resonator, which effectively solves the problem of incomplete symmetry of circuit parameters compared with the two-path amplifier circuit structure.

[0006] A vibration signal reading method of an axisymmetric gyro based on a rotating carrier, the method comprising the following steps:

[0007] Step 1) DDS initial carrier signal generator generates an initial carrier cosω c t, DDS rotating carrier sine signal generator generates a rotating carrier sinωt, and DDS rotating carrier cosine signal generator generates a rotating carrier cosωt.

[0008] Step 2) The carrier signal cosω c t is decomposed by the rotating carrier, and after being modulated by the x-axis rotating carrier cosωt and the y-axis rotating carrier sinωt respectively, the x-axis carrier signal cosω c tcosωt and the y-axis carrier signal cosω c tsinωt are generated. Wherein, ω cLet ω be the frequency of the initial carrier wave (single-channel), cosωt be the carrier frequency decomposed to the x-axis, and sinωt be the carrier frequency decomposed to the y-axis. To address the issue that a single-channel initial carrier wave cannot generate an excitation signal with angular direction changes, a rotating carrier signal is added, and the initial carrier signal cosωt is decomposed to the x-axis. c When t is modulated onto a sine and cosine signal that varies with frequency ω, the excitation signals cosω of the two paths are... c tcosωt,cosω c The combination of tsinωt generates excitation signals in different angles and directions.

[0009] Step 3) Generate the two carrier signals, i.e., the carrier signal cosω of the x-channel. c The carrier signal cosωt of the t and y paths c The x and y electrodes of the gyroscope resonator are excited by tsinωt, respectively, causing a slight change in capacitance on the surface of the gyroscope structure. This change is picked up and read by the front-end amplifier circuit, and then converted into V by the capacitance-to-voltage conversion circuit. o , which contains ω d ,ω,ω c In addition to combined harmonic components and higher harmonic components.

[0010] Step 4) Read out the signal V o Initial carrier demodulation is performed using the initial carrier signal generated by the DDS initial carrier signal generator, i.e., cosω. c t is multiplied by the readout signal, and then filtered by a low-pass filter to remove ω. c And its high-frequency harmonic components.

[0011] Step 5) Perform rotating carrier demodulation on the signal after initial carrier demodulation. Multiply the x-axis rotating decomposed signal (cosωt) generated by the DDS rotating carrier cosine signal generator with the signal after initial carrier demodulation, and then pass it through a low-pass filter to remove ω and its high-frequency harmonic components. Multiply the y-axis rotating decomposed signal (sinωt) generated by the DDS rotating carrier sine signal generator with the signal after initial carrier demodulation, and then pass it through a low-pass filter to remove ω and its high-frequency harmonic components, finally retaining the signal containing the resonant frequency ω. d The initial x-electrode displacement signal V x and the initial y-electrode displacement signal V y .

[0012] Furthermore, in step 1), the DDS digital generator is a direct frequency synthesizer, capable of outputting the required sine and cosine signals based on the input voltage signal. In this system, the DDS needs to generate two signals with different frequencies, namely, generating an initial carrier signal cosω. ct and the rotating carrier signals cosωt and sinωt with frequencies ω c and ω, where ω c is the single-channel carrier signal frequency to avoid gain adaptation problems in the front-end amplification circuit caused by multiple carrier frequencies, and the size of ω affects the rotation rate of the initial carrier. The carrier generated by the DDS not only provides the excitation signal for the gyroscopic resonator, but also provides the demodulation signal cosω c t for the initial carrier demodulation module, and the DDS rotating carrier signal generator provides the demodulation signals cosωt and sinωt for the rotating carrier demodulation module. In addition, it is ensured that the ω c and ω frequency components and their higher harmonic components can be successfully filtered out in the subsequent filter demodulation module, and the size of ω c and ω is at least one order of magnitude larger than the resonant frequency ω d , and ω c needs to be at least one order of magnitude larger than ω, so that the frequency spectrum of the modulated signal is far away from the resonant frequency ω d , and at the same time, enough frequency space size is left for the design of the filter.

[0013] Further, step 2) decomposes the carrier signal cosω c t into the x-axis rotating carrier cosωt and the y-axis rotating carrier sinωt, respectively, and modulates them to generate the x-channel carrier signal cosω c tcosωt and the y-channel carrier signal cosω c tsinωt. Wherein, ω c is the frequency of the single-channel initial carrier, ω is the frequency of the rotating decomposed carrier, cosωt represents the carrier decomposed to the x-axis, and sinωt represents the carrier decomposed to the y-axis. To solve the problem that the initial carrier with a single-channel frequency cannot generate an excitation signal with angular direction changes, the rotating carrier signal is added to modulate the initial carrier signal cosω c t on the cosine signal with a frequency of ω, at this time, the two-channel excitation signals cosω c tcosωt and cosω c tsinωt combine to generate excitation signals with different angular directions.

[0014] Further, in step 3), the excitation mode of the axisymmetric gyroscope is a flat plate capacitive electrostatic excitation, and the excitation is only related to the voltage on the electrode. In terms of readout signals, the weak change amount of the capacitor is extracted from the resonator structure, and the capacitive change amount ΔC of each mode is only positively correlated with the displacement of the corresponding mode, so it can be set that:

[0015]

[0016] Where ω dThe readout current is calculated according to the formula as follows:

[0017]

[0018] The displacement signals of the x electrode and the y electrode are read out by one front-end circuit, avoiding errors caused by parameter asymmetry of two front-end processing circuits. The signals are processed and amplified by a front-end amplifier, and then converted into a voltage signal V o , which contains the modulation signals of the x electrode and the y electrode, contains ω d , ω c , combined harmonic components and high-order harmonic components, and contains ω c + ω + ω d , ω c + ω - ω d , ω c - ω + ω d , ω c - ω - ω d .

[0019] In step 3), the x-channel carrier signal cos ω c tcos ωt and the y-channel carrier signal cos ω c tsin ωt are respectively used to excite the x electrode and the y electrode of the gyro resonator, so that a weak capacitance change is generated on the surface of the gyro resonator, which is picked up and read out by a front-end amplification circuit, and is amplified as much as possible without distortion to a magnitude that can be recognized by a subsequent initial carrier demodulation and a rotating carrier demodulation module, and is converted into a readout signal V o , which contains ω d , ω c , combined harmonic components and high-order harmonic components, and ω d is the resonant frequency of the gyro resonator. In the front-end readout system in the system, only one front-end amplification processing circuit is used, and the readout signal contains the original displacement signals of the x electrode and the y electrode, avoiding the readout signal error problem caused by parameter asymmetry of the double-channel readout circuit.

[0020] In step 3), the x-channel carrier signal cos ω c tcos ωt and the y-channel carrier signal cos ω c tsin ωt are respectively used to excite the x electrode and the y electrode of the gyro resonator, so that a weak capacitance change is generated on the surface of the gyro resonator, which is picked up and read out by a front-end amplification circuit, and is amplified as much as possible without distortion to a magnitude that can be recognized by a subsequent initial carrier demodulation and a rotating carrier demodulation module, and is converted into a readout signal V o , which contains ωd ,ω,ω c And combined harmonic components and higher harmonic components, where ω d This is the resonant frequency of the gyroscope resonator. In this system, only one front-end amplification circuit is used in the front-end readout system. The readout signal simultaneously contains the original displacement signals of both the x and y electrodes, avoiding the readout signal error problem caused by parameter asymmetry in dual-channel readout circuits.

[0021] Further, in step 4), the signal V is read out. o The modulation process involves two modulation stages, introducing two modulation frequencies: the frequency ω introduced by carrier modulation. c The frequency ω introduced by the rotating carrier decomposition modulation contains harmonic components of ω. c +ω+ω d ω c +ω-ω d ω c -ω+ω d ω c -ω-ω d Therefore, demodulation is required twice to preserve the resonant frequency ω in the initial displacement signal. d Read out signal V o First, it undergoes demodulation by the initial carrier module to filter out ω. c The component, i.e., the initial carrier signal generated by the DDS initial carrier signal generator, is cosω. c t and readout signal V o By multiplying, the carrier wave cosω can be filtered out. c The frequency component of t, and for 2ω c High-frequency harmonic components, etc., can be filtered out from the original signal using only a low-pass filter. c Due to the influence of components, the signal after the initial carrier demodulation module contains the following components: ω + ω d With ω-ω d .

[0022] Further, in step 5), the signal demodulated by the initial carrier is subjected to rotating carrier demodulation. The x-axis rotating decomposition signal (cosωt) generated by the DDS rotating carrier cosine signal generator is multiplied with the signal demodulated by the initial carrier, and then filtered by a low-pass filter to remove ω and its high-frequency harmonic components. The y-axis rotating decomposition signal (sinωt) generated by the DDS rotating carrier sine signal generator is multiplied with the signal demodulated by the initial carrier, and then filtered by a low-pass filter to remove ω and its high-frequency harmonic components, ultimately retaining the signal containing the resonant frequency ω. d The initial x-electrode displacement signal V x and the initial y-electrode displacement signal V y .

[0023] The advantages of the present application over the prior art are as follows: due to the limitations of the process, only half of the electrodes in the vibration signal reading method of the axisymmetric gyroscope under the time-division multiplexing scheme work in the reading state, it is difficult to realize symmetric differential detection, and at the reading end, the reading signals of the x and y axes will pass through two independent signal processing circuits, and due to the parameter errors on the circuit, the asymmetry of the two will also cause large errors in the reading signals. The reading scheme under the dual-frequency carrier uses two carrier signals of different frequencies to excite two electrodes respectively, and reads by one channel, which improves the error, but at the same time, the carriers of different frequencies have different frequency responses, which introduces a new gain adaptation problem at the reading end. The present application adopts a vibration signal reading method of an axisymmetric gyroscope based on a rotating carrier, that is, a DDS digital generator is used to generate a single-frequency carrier cosω c t and a rotating decomposition carrier sinω c tcosω c tsinω o t on the sine and cosine signals with a frequency of ω respectively, and excite the x and y electrodes respectively, and then read by one front-end amplifier circuit, one front-end processing circuit also avoids the error introduced by the asymmetry of the two front-end processing circuits. After that, the capacitance / voltage conversion circuit generates V c , and the reading signal quantity after two modulations is used for demodulation twice, that is, initial carrier demodulation and rotating carrier demodulation, to filter out ω x and ω y frequencies to extract the initial displacement voltage signals V c and V x , which not only avoids the error caused by the time-division multiplexing reading system, but also avoids the gain adaptation problem at the reading end caused by the carriers of different frequencies in the dual-frequency carrier reading scheme. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is the system implementation block diagram of the present application;

[0025] Figure 2 is the principle block diagram of the rotating decomposition carrier module of the present application;

[0026] Figure 3 is the waveform diagram of the rotating decomposition carrier module of the present application;

[0027] Figure 4 is the implementation block diagram of the initial carrier demodulation module of the present application;

[0028] Figure 5This is a block diagram illustrating the implementation of the rotating carrier demodulation module of the present invention. Detailed Implementation

[0029] To enhance understanding of the present invention, the embodiments will be described in detail below with reference to the accompanying drawings.

[0030] Example 1: A vibration signal readout system for an axisymmetric gyroscope based on a rotating carrier wave, such as... Figure 1 As shown, the system includes a gyro resonator, a DDS initial carrier signal generator, a DDS rotating carrier cosine signal generator, a DDS rotating carrier sine signal generator, a front-end amplifier module, a capacitor / voltage conversion circuit module, an initial carrier demodulation module, and a rotating carrier demodulation module. The initial carrier signal cosω is generated by the DDS digital generator. c t and the rotating carrier signals cosωt and sinωt, the initial carrier signal cosω c When t is modulated with the rotating carriers cosωt of the x-axis and sinωt of the y-axis respectively, an x-channel carrier signal cosωt in any direction can be generated. c The carrier signal cosωt of the t and y paths c tsinωt. Furthermore, the two generated carrier signals excite the x and y electrodes of the gyroscope resonator respectively. The resulting change in surface capacitance is detected by an amplifier circuit and converted into V through a capacitor / voltage converter circuit. o , which contains ω d ,ω,ω c In addition to combined harmonic components and higher-order harmonic components. After initial carrier demodulation, ω is removed. c The frequency ω and its higher harmonic components are demodulated separately in two paths by rotating carrier demodulation. ω and its higher harmonic components are removed, and finally, frequency ω is retained. d And this includes the original displacement signal V of the x electrode. x and the original displacement signal V of the y electrode y .

[0031] Example 2: A method for reading out vibration signals from an axisymmetric gyroscope based on a rotating carrier wave. For example... Figure 1 As shown, the entire system includes a gyroscope resonator, a DDS initial carrier signal generator, a DDS rotating carrier cosine signal generator, a DDS rotating carrier sine signal generator, a front-end amplifier module, a capacitor / voltage conversion circuit module, an initial carrier demodulation module, and a rotating carrier demodulation module. The DDS initial carrier signal generator produces the initial carrier cosω. c The DDS rotating carrier sine wave generator generates a carrier wave sinωt, and the DDS rotating carrier cosine wave generator generates a carrier wave cosωt. Additionally, it ensures that ωt can be successfully filtered out in the subsequent filtering and demodulation module. cAnd the ω frequency component and its higher harmonic components, ω c And the magnitude of ω must be greater than the resonant frequency ω. d At least one order of magnitude, and ω c It needs to be at least an order of magnitude greater than ω, so that the spectrum of the modulated signal is far from the resonant frequency ω. d At the same time, sufficient frequency space is reserved for filter design. The carrier signal cosω c The signal t is decomposed by a rotating carrier wave and modulated with the rotating carrier waves cosωt of the x-axis and sinωt of the y-axis respectively, to generate the carrier signal cosωt of the x-axis. c The carrier signal cosωt of the t and y paths c tsinωt, the schematic implementation is as follows Figure 2 As shown. Where ω c Let ω be the frequency of the initial carrier wave (single-channel), cosωt be the carrier frequency decomposed to the x-axis, and sinωt be the carrier frequency decomposed to the y-axis. To address the issue that a single-channel initial carrier wave cannot generate an excitation signal with angular direction changes, a rotating carrier signal is added, and the initial carrier signal cosωt is decomposed to the x-axis. c When t is modulated onto a sine and cosine signal that varies with frequency ω, the excitation signals cosω of the two paths are... c tcosωt,cosω c The combination of tsinωt generates excitation signals in different angular directions, and the resulting waveforms are shown in the figure. Figure 3 As shown. Further, the generated carrier signal excites the x and y electrodes of the hemispherical gyroscope respectively. The axisymmetric gyroscope is excited by a parallel plate capacitor electrostatic excitation method, and its excitation is only related to the voltage on the electrodes. Regarding the readout signal, the weak changes in the capacitor are extracted from the resonant oscillator structure. Since the capacitance change ΔC of each mode is only positively correlated with the displacement of the corresponding mode, it can be assumed that:

[0032]

[0033] Where ω d Given the resonant frequency of the gyroscope resonator, the readout current can be calculated using the formula:

[0034]

[0035] The displacement signals of the x and y electrodes are simultaneously read from a single front-end circuit, avoiding errors introduced by parameter asymmetry between the two front-end processing circuits. This signal is amplified by a front-end amplifier and then converted into a voltage signal V by a capacitor-to-voltage converter circuit. o It contains the modulation signals of the x and y electrodes, and contains ω d ,ω,ω cIn addition to combined harmonic components and higher-order harmonic components, the harmonic components included are ω c +ω+ω d ω c +ω-ω d ω c -ω+ω d ω c -ω-ω d For the modulated signal quantity V o Two modulation frequencies were introduced: the frequency ω introduced by carrier modulation. c The frequency ω introduced by the rotating carrier decomposition modulation contains harmonic components of ω. c +ω+ω d ω c +ω-ω d ω c -ω+ω d ω c -ω-ω d Therefore, demodulation is required twice to preserve the resonant frequency ω in the initial displacement signal. d Read out signal V o First, it undergoes demodulation by the initial carrier module. The specific implementation principle is as follows: Figure 4 As shown. To filter out ω c The component, i.e., the initial carrier signal generated by the DDS initial carrier signal generator, is cosω. c t and readout signal V o By multiplying, the carrier wave cosω can be filtered out. c The frequency component of t, and for 2ω c High-frequency harmonic components, etc., can be filtered out from the original signal using only a low-pass filter. c Due to the influence of components, the signal after the initial carrier demodulation module contains the following components: ω + ω d With ω-ω d The signal after initial carrier demodulation is then subjected to rotated carrier demodulation. The specific implementation principle is as follows: Figure 5 As shown, the x-axis rotation decomposition signal (cosωt) generated by the DDS rotating carrier cosine signal generator is multiplied by the demodulated signal of the initial carrier, and then filtered by a low-pass filter to remove ω and its high-frequency harmonic components. Similarly, the y-axis rotation decomposition signal (sinωt) generated by the DDS rotating carrier sine signal generator is multiplied by the demodulated signal of the initial carrier, and then filtered by a low-pass filter to remove ω and its high-frequency harmonic components, ultimately retaining the signal containing the resonant frequency ω. d The initial x-electrode displacement signal V x and the initial y-electrode displacement signal V y .

[0036] It should be noted that the above examples are not intended to limit the scope of the present application, and equivalent transformations or substitutions made on the basis of the above technical solutions all fall within the scope of the claims of the present application.

Claims

1. A vibration signal readout system for a rotationally-carried axisymmetric gyroscope, characterized by, The system includes a gyro resonator, a DDS initial carrier signal generator, a DDS rotating carrier cosine signal generator, a DDS rotating carrier sine signal generator, a front-end amplifier module, a capacitor / voltage conversion circuit module, an initial carrier demodulation module, and a rotating carrier demodulation module. First, the DDS initial carrier signal generator generates an initial carrier cosω. c The DDS rotating carrier sine wave generator generates a rotating carrier sinωt along the y-axis, and the DDS rotating carrier cosine wave generator generates a rotating carrier cosωt along the x-axis. Then, the initial carrier cosωt... c t is modulated with the rotating carriers cosωt of the x-axis and sinωt of the y-axis, respectively, with the initial carrier cosωt c Under the influence of a rotating carrier wave cosωt along the x-axis and a rotating carrier wave sinωt along the y-axis, the direction of the generated component changes with the frequency ω of the rotating carrier wave. c The changing x-channel carrier signal cosω c The carrier signal cosωt of the t and y paths c tsinωt, to achieve excitation signal generation at arbitrary angles, and generate x-channel carrier signals cosω c The carrier signal cosωt of the t and y paths c tsinωt excites the x and y electrodes of the gyroscope resonator, respectively. The resulting change in capacitance on the spherical shell surface is amplified by the front-end amplifier circuit and converted into a voltage V by the capacitor-to-voltage converter circuit. o At this time, it contains ω d ,ω,ω c And combined harmonic components and higher harmonic components, voltage quantity V o First, it passes through the initial carrier demodulation module to remove ω. c Its higher harmonic components are then demodulated separately in two paths by a rotating carrier demodulation module to remove ω and its higher harmonic components, while retaining the resonant frequency ω. d Finally, the original displacement signal V containing the x electrode was extracted. x and the original displacement signal V of the y electrode y .

2. A vibration signal readout system for a rotationally-carried axisymmetric gyroscope according to claim 1, characterized in that: In the generating excitation carrier link, a DDS carrier signal generator is used to generate an initial carrier, and the x-axis rotating carrier cosωt and the y-axis rotating carrier sinωt are generated. The initial carrier signal cosω c t is modulated on the sine and cosine waveforms with frequency ω respectively. At this time, the x-axis carrier signal cosω c tcosωt and the y-axis carrier signal cosω c tsinωt can achieve signal excitation at any angle.

3. A method of reading out a vibration signal of an axisymmetric gyroscope based on a rotating carrier, characterized in that The method comprises the following steps: step 1) generating an initial carrier signal cos ωt by a DDS initial carrier signal generator c t, generating a rotating carrier sin ωt of the y-axis by a DDS rotating carrier sine signal generator, and generating a rotating carrier cos ωt of the x-axis by a DDS rotating carrier cosine signal generator, Step 2) Initial carrier signal cosωt c tcosωt and y route carrier signal cosω c tcosωt and y route carrier signal cosω c tsinωt, where ω is the frequency of the angle change, the initial carrier signal cosω c tis modulated on the sine cosine waveform with a frequency of ω to achieve the extraction of carrier components at any angle, Step 3) The generated two-channel carrier signals, i.e. the x-channel carrier signal cosω c tcosωt and the y-channel carrier signal cosω c tsinωt, respectively excite the x-electrode and the y-electrode of the gyro resonator, so that a weak capacitance change is generated on the surface of the gyro resonator structure, which is picked up and read out by a front-end amplification circuit, and converted into V o , which contains ω d , ω, ω c and combined harmonic components and high-order harmonic components, Step 4) multiplying the read signal V o The initial carrier demodulation is performed using the initial carrier signal generated by the DDS initial carrier signal generator, i.e. cos ω c t, with the read signal and passing through a low-pass filter to filter out the ω c and its high harmonic frequency components, Step 5) Perform rotating carrier demodulation on the signal after initial carrier demodulation. Multiply the x-axis rotating decomposed signal (cosωt) generated by the DDS rotating carrier cosine signal generator with the signal after initial carrier demodulation, and then pass it through a low-pass filter to remove ω and its high-frequency harmonic components. Multiply the y-axis rotating decomposed signal (sinωt) generated by the DDS rotating carrier sine signal generator with the signal after initial carrier demodulation, and then pass it through a low-pass filter to remove ω and its high-frequency harmonic components, finally retaining the signal containing the resonant frequency ω. d The initial x-electrode displacement signal V x and the initial y-electrode displacement signal V y .

4. The vibration signal readout method for a rotationally-carried axisymmetric gyroscope according to claim 3, characterized by, Step 1) DDS digital generator is a direct frequency synthesizer, which can output the required sine and cosine signals according to the input voltage signal. DDS needs to generate two different frequency signals, i.e. generate a initial carrier signal cosω c t and a rotating carrier signal cosωt and sinωt, whose frequencies are ω c and ω respectively, where ω c is the frequency of the single carrier signal. The DDS initial carrier signal generator provides the demodulation signal cosω c t for the initial carrier demodulation module. The DDS rotating carrier signal generator provides the demodulation signal cosωt and sinωt for the rotating carrier demodulation module, which ensures that the ω c and ω frequency components and their high harmonic components can be successfully filtered out in the subsequent filter demodulation module. The size of ω c and ω is at least one order of magnitude larger than the resonant frequency ω d , and the size of ω c t is at least one order of magnitude larger than ω, so that the frequency spectrum of the modulated signal is far away from the resonant frequency ω d , and at the same time, there is enough frequency space size for the design of the filter.

5. The vibration signal readout method for a rotationally-carried axisymmetric gyroscope according to claim 3, characterized by, Step 2) the carrier signal cosω c t is modulated by the rotating carrier cosω c tcosωt and the y-axis rotating carrier sinω c t, where ω c is the frequency of the original carrier signal, ω is the frequency of the rotating carrier, cosω c t represents the carrier decomposed to the x-axis, and sinω c tcosωt and cosω c tsinωt are combined to generate the excitation signal with different angular directions.

6. The vibration signal readout method for a rotationally-carried axisymmetric gyroscope according to claim 3, characterized by, In step 3), the axisymmetric gyroscopes are excited by means of flat-plate capacitive electrostatic excitation, and the excitation is only related to the voltage on the electrode. In terms of the readout signal, the weak change amount of the capacitor is extracted from the resonator structure. The capacitive change amount ΔC of each mode is only positively correlated with the displacement of the corresponding mode. Assuming that: where ω d is the resonant frequency of the gyroharmonic oscillator, the readout current is found from the equation The displacement signals of the x electrode and the y electrode are simultaneously read out by a front-end circuit, the signals are amplified by a front-end amplifier, and then are converted into a voltage signal V by a capacitance / voltage conversion circuit o The modulation signals of the x electrode and the y electrode contain ω d , ω, ω c and combined harmonic components and high-order harmonic components, and the contained harmonic components are ω c + ω + ω d , ω c + ω - ω d , ω c - ω + ω d , ω c - ω - ω d .

7. The vibration signal readout method for a rotationally-carried axisymmetric gyroscope according to claim 3, characterized by, In step 4), the read signal quantity V o after the front-end circuit is demodulated once by the initial carrier demodulation module, the initial carrier signal generated by the DDS initial carrier signal generator, i.e. cosω c t, is multiplied with the read signal V o to filter out the frequency component of the carrier cosω c t, and a low-pass filter is used to filter out the high frequency component of ω c from the original signal for the high harmonic component of 2ω c , at this time, the filtered signal contains ω d , ω and the combination harmonic component and high harmonic component.

8. The vibration signal readout method for a rotationally-carried axisymmetric gyroscope according to claim 3, characterized by, Step 5) The signal after initial carrier demodulation is divided into two paths to carry out rotating carrier demodulation respectively, i.e. to demodulate ω d , ω and combined harmonic component and high harmonic component, for x path, DDS rotating carrier cosine signal generator is used to generate signal cosωt to multiply with the signal after initial carrier demodulation, and a low pass filter is used to filter out ω and high harmonic frequency component, and to reserve x axis displacement signal V d containing harmonic frequency ω x ; DDS rotating carrier sine signal generator is used to generate signal sinωt to multiply with the signal after initial carrier demodulation, and a low pass filter is used to filter out ω and high harmonic frequency component, and to reserve y axis displacement signal V d containing harmonic frequency ω y .

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