A kind of hemispherical harmonic oscillator non-contact excitation device and frequency characteristic identification method

Abstract

The application discloses a kind of hemispherical resonator non-contact excitation device and frequency characteristic identification method, the device includes quartz sleeve, four separate interdigital electrodes, vacuum device and Doppler laser vibration measurement system.The quartz sleeve is a hollow cylinder without cover up and down, the included angle between the four separate interdigital electrodes is 90 °, plated on quartz sleeve, the Doppler laser vibration measurement system is used to measure resonator vibration signal.The frequency characteristic identification method includes rigid shaft identification method and frequency difference identification method, the rigid shaft identification method is under the same size excitation, two-point resonator vibration signal with angle difference of 22.5 ° is measured in two steps, and the rigid shaft angle of resonator is fitted out;The frequency difference identification method is beat frequency measurement method, after selecting a point on resonator excitation, the frequency difference size is identified by measuring resonator vibration beat frequency signal.The application is a kind of non-contact excitation method, and the surface state of resonator will not be damaged.

Description

Technical Field

[0001] This invention belongs to the field of hemispherical resonator gyroscope technology. It designs a non-contact excitation method and frequency characteristic identification method for hemispherical resonators, which is applied to the vibration excitation of hemispherical resonators and the identification of frequency characteristics such as frequency difference and rigid axis. Background Technology

[0002] The hemispherical resonant gyroscope is a novel type of vibrating gyroscope. The standing wave generated by the oscillating hemispherical harmonic oscillator exhibits a significant precession effect as the outer base rotates. Hemispherical resonant gyroscopes possess superior application characteristics such as miniaturization, low cost, high precision, high stability, and long lifespan, and are widely used in weaponry such as naval vessels, individual combat vehicles, guided weapons, and satellites.

[0003] As the most crucial component of a hemispherical resonator gyroscope, the performance of the hemispherical resonator plays a decisive role in the overall performance of the gyroscope. During the fabrication of the hemispherical resonator, it is impossible to achieve near-perfect properties. In particular, uneven circumferential mass of the hemispherical resonator can cause frequency fragmentation during oscillation, and this frequency difference directly affects the testing accuracy of the entire gyroscope. Therefore, the resonator frequency difference needs to be leveled before the gyroscope can be assembled. Thus, the resonator frequency difference is a key factor affecting gyroscope performance, requiring identification and leveling. The non-destructive and accurate identification of the hemispherical resonator's frequency difference and the location of its rigid axis is crucial.

[0004] Frequency difference identification of a hemispherical harmonic oscillator requires the oscillator to be in a vibrating state. Currently, the commonly used vibration excitation methods are the small hammer contact excitation method and the planar single-point interdigitated electrode excitation method. Among them, the small hammer excitation method may damage the oscillator surface, cannot control the magnitude of the excitation force, and has problems such as stress application to the oscillator. The single-point interdigitated electrode has problems such as small excitation force and inability to select the excitation position of the oscillator while the oscillator is kept fixed. Summary of the Invention

[0005] To address the problems of potential damage to the oscillator surface and the inability to select the oscillator excitation location while keeping the oscillator fixed, the present invention aims to provide a non-contact hemispherical resonator excitation device and frequency characteristic identification method to overcome the problems existing in the prior art.

[0006] To achieve the above objectives, the non-contact hemispherical resonator excitation device provided by this invention adopts the following technical solution:

[0007] A non-contact excitation device for a hemispherical resonator includes a quartz sleeve, four discrete interdigitated electrodes, a vacuum device, and a Doppler laser vibration measurement system.

[0008] The quartz sleeve is a hollow cylinder without top or bottom caps.

[0009] The four discrete interdigitated electrodes are spaced at a 90° angle and plated onto a quartz sleeve.

[0010] The vacuum device includes a combined pump system and a vacuum chamber.

[0011] The Doppler laser vibration measurement system is used to measure the vibration signal of the harmonic oscillator and to identify the frequency difference and rigid shaft.

[0012] Furthermore, the quartz sleeve has a notch located in the middle of two adjacent interdigitated electrodes for laser vibration measurement of the resonator.

[0013] Furthermore, the quartz sleeve has Z-axis movement capability.

[0014] Furthermore, the interdigitated electrodes are arranged in a comb-like pattern and have a periodic structure.

[0015] According to another aspect of the present invention, a method for identifying the frequency characteristics of a non-contact excitation device for a hemispherical resonator is provided, including a rigid shaft identification method and a frequency difference identification method, and the technical solution is as follows:

[0016] Install the oscillator in the vacuum chamber. After the oscillator is fixed, move the interdigitated electrode in the z-direction so that the electrode position is directly opposite the upper side wall of the oscillator lip, and keep the distance between the interdigitated electrode and the oscillator within the set range.

[0017] The rigid shaft identification method involves measuring the vibration signals of two oscillators with an angle difference of 22.5° in two steps under the same excitation magnitude, and fitting the rigid shaft angle of the oscillator.

[0018] The frequency difference identification method is the beat frequency measurement method. After selecting a point on the resonator for excitation, the magnitude of the frequency difference is identified by measuring the beat frequency signal of the resonator vibration.

[0019] Furthermore, a combined pump system is used to evacuate the chamber environment where the oscillator is located to a vacuum level, keeping the air damping at a low level when the oscillator vibrates, and the interdigitated electrodes are energized;

[0020] Furthermore, the frequency difference identification method is as follows: an AC voltage with the same frequency as the resonant frequency of the resonant oscillator is applied to the interdigital electrodes to excite the resonant oscillator to vibrate at its resonant frequency. The oscillator signal is acquired by a Doppler laser vibration measurement system. The signal measurement point is any point on the oscillator. In order to record the vibration signal of the oscillator, two troughs in the beat frequency envelope are found in the signal diagram. The reciprocal of the time interval between the two troughs is the magnitude of the frequency difference of the resonant oscillator.

[0021] Furthermore, the method for identifying the rigid axis of the harmonic oscillator is as follows:

[0022] The first step is to select any point on the oscillator for excitation and obtain the vibration signal at that point. The second step is to apply the same excitation to the oscillator as in the first step, so that the amplitude of the oscillator measured in the second step is basically the same as the amplitude in the first step. The oscillator signal measurement point is 22.5° away from the first measurement point. Two vibration signals are obtained. Each signal is the synthesis of the components of the two rigid shaft vibration signals at that point. By comparing the amplitudes of the two signals that are 22.5° apart, the positions of the two rigid shafts can be determined.

[0023] The advantages of this invention compared to the prior art are:

[0024] (1) It is a non-contact excitation method that will not damage the surface condition of the oscillator;

[0025] (2) By controlling the magnitude of the driving voltage, the force of each excitation of the oscillator can be kept consistent, thus simplifying the measurement process.

[0026] (3) It is a multi-point side excitation method. Compared with the end face excitation method of the oscillator, the effective area is larger and the excitation force is greater, making the oscillator vibration signal easier to measure. Attached Figure Description

[0027] The accompanying drawings, which form part of this specification, are provided to further illustrate embodiments of the invention and, together with the textual description, explain the principles of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0028] Figure 1 A schematic diagram of an interdigital electrode-resonator system structure according to a specific embodiment of the present invention is shown. Detailed Implementation

[0029] 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.

[0030] A non-contact hemispherical resonator excitation device includes a quartz sleeve, four discrete interdigitated electrodes, a resonator fixing device, a vacuum device, and a Doppler laser vibration measurement system.

[0031] The quartz sleeve is a hollow cylinder without top or bottom caps, with a notch located between two adjacent interdigital electrodes for signal detection. The four discrete interdigital electrodes are spaced at a 90° angle and are fixed by a three-claw structure. The four discrete interdigital electrodes are plated onto the quartz sleeve to excite the hemispherical resonator to vibrate. The quartz sleeve has Z-axis movement capability.

[0032] The vacuum device includes a combined pump system and a vacuum chamber.

[0033] The Doppler laser vibration measurement system is used to measure the vibration signal of the harmonic oscillator and to identify the frequency difference and rigid shaft.

[0034] Furthermore, the interdigitated electrodes are arranged in a comb-like pattern, exhibiting a periodic structure. In this embodiment, the interdigitated electrodes are cylindrical and positioned outside the hemispherical harmonic oscillator. A schematic diagram is attached. Figure 1 A capacitor structure is formed between the interdigital electrodes and the resonator. The weak vibration of the resonator and the voltage change of the interdigital electrodes will cause the capacitance to change. Theoretically, the vibration of the resonator can be detected by measuring the change in capacitance. Alternatively, the resonator can be excited to vibrate by applying a specific frequency voltage to the interdigital electrodes. This invention uses the interdigital electrode excitation function.

[0035] The area between the interdigitated electrode and the oscillator is approximately a flat plate electrode, and the capacitance satisfies the following equation:

[0036]

[0037] In the formula, ε is the relative permittivity, ε0 ​​is the vacuum permittivity, S is the effective area of ​​the plate capacitor, and d is the distance between the two plates. By controlling the appropriate spacing, the initial capacitance of the two plates is controlled within the set range. When an AC voltage is applied to the interdigital electrodes, the excitation process of the oscillator can be completed.

[0038] Based on the above-mentioned non-contact hemispherical resonator excitation device, the present invention provides a frequency characteristic identification method, including a rigid shaft identification method and a frequency difference identification method.

[0039] After ultrasonic cleaning and drying, the oscillator is installed in the vacuum chamber. After the oscillator is fixed, the interdigitated electrode is moved in the z-direction so that the electrode position is directly opposite the upper side wall of the oscillator lip, keeping the distance between the interdigitated electrode and the oscillator within the set range.

[0040] The rigid shaft identification method involves measuring the vibration signals of two oscillators with an angle difference of 22.5° in two steps under the same excitation magnitude, and fitting the rigid shaft angle of the oscillator.

[0041] Choose any point on the harmonic oscillator as the initial excitation point, with an excitation amplitude of A0. Let the angle between this point and one of the rigid axes be θ0. Then, the components on the two rigid axes are...

[0042] A1 = A0cos(2θ0)

[0043] A2 = A0sin(2θ0)

[0044] The amplitude of the point at an angle θ from the rigid axis is

[0045] A θ =A1cos(2θ)+A2sin(2θ)=A0[cos(2θ0)cos(2θ)+sin(2θ0)sin(2θ)]

[0046] While ensuring that A0 is consistent, the first measurement angle is θ0, and the second measurement angle is θ0+22.5°. By comparing the amplitudes of the two sets of data, θ0 can be calculated, and the angular position points of the two rigid axes can be identified.

[0047] The frequency difference identification method is the beat frequency measurement method. After selecting a point on the resonator for excitation, the magnitude of the frequency difference is identified by measuring the beat frequency signal of the resonator vibration.

[0048] Specifically, the frequency difference identification method is as follows:

[0049] A dry pump-molecular pump combination system is used to evacuate the chamber environment where the oscillator is located to a vacuum level, so that the air damping is kept at a low level when the oscillator vibrates, and the interdigitated electrodes are energized.

[0050] An AC voltage with the same frequency as the resonant frequency of the resonant oscillator is applied to the interdigitated electrodes to excite the oscillator to vibrate at its resonant frequency. The oscillator signal is acquired using a Doppler laser vibration measurement system, and the signal measurement point can be any point on the oscillator. The frequency difference is measured by recording the oscillator's vibration signal, finding the two troughs in the beat frequency envelope of the signal diagram, and the reciprocal of the time interval between the two troughs is the magnitude of the frequency difference of the resonant oscillator.

[0051] The rigid shaft identification method is as follows:

[0052] Identifying the rigid axis of a resonator requires two steps. The first step involves selecting an arbitrary point on the oscillator for excitation and obtaining the vibration signal at that point. The second step applies the same excitation as in the first step, ensuring that the amplitude of the oscillator in the second measurement is approximately the same as in the first step. The oscillator signal measurement point is located 22.5° from the first measurement point. This yields two vibration signals, each a synthesis of the components of the two rigid axis vibration signals at that point. Because the amplitudes of the two excitations are essentially the same, comparing the amplitudes of the two signals, which differ by 22.5°, allows the determination of the positions of the two rigid axes, facilitating subsequent frequency correction of the resonator.

[0053] 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 frequency characteristic identification method based on a non-contact excitation device of a hemispherical resonator, including a rigid shaft identification method and a frequency difference identification method, characterized in that, The non-contact excitation device for the hemispherical resonator includes a quartz sleeve, four discrete interdigitated electrodes, a vacuum device, and a Doppler laser vibration measurement system. The quartz sleeve is a hollow cylinder without top or bottom caps. The four discrete interdigitated electrodes are spaced at a 90° angle and plated onto a quartz sleeve. The vacuum device includes a combined pump system and a vacuum chamber. The Doppler laser vibration measurement system is used to measure the vibration signal of the harmonic oscillator and to identify the frequency difference and rigid shaft. The frequency characteristic identification method includes: Install the oscillator in the vacuum chamber. After the oscillator is fixed, move the interdigitated electrode in the z-direction so that the electrode position is directly opposite the upper side wall of the oscillator lip, and keep the distance between the interdigitated electrode and the oscillator within the set range. The rigid shaft identification method involves measuring the vibration signals of two oscillators with an angle difference of 22.5° in two steps under the same excitation magnitude, and fitting the rigid shaft angle of the oscillator. The frequency difference identification method is the beat frequency measurement method. After selecting a point on the resonator for excitation, the magnitude of the frequency difference is identified by measuring the beat frequency signal of the resonator vibration. The method for identifying the rigid axis of a harmonic oscillator is as follows: The first step is to select any point on the oscillator for excitation and obtain the vibration signal at that point. The second step is to apply the same excitation to the oscillator as in the first step, so that the amplitude of the oscillator measured in the second step is basically the same as the amplitude in the first step. The oscillator signal measurement point is 22.5° away from the first measurement point. Two vibration signals are obtained. Each signal is the synthesis of the components of the two rigid shaft vibration signals at that point. By comparing the amplitudes of the two signals that are 22.5° apart, the positions of the two rigid shafts can be determined.

2. The frequency characteristic identification method according to claim 1, characterized in that, The frequency difference identification method is as follows: A combined pump system is used to evacuate the chamber environment where the oscillator is located to a vacuum level, keeping the air damping at a low level when the oscillator vibrates, and the interdigitated electrodes are energized. An AC voltage with the same frequency as the resonant frequency of the harmonic oscillator is applied to the interdigital electrodes to excite the harmonic oscillator to vibrate at its resonant frequency. The oscillator signal is acquired by a Doppler laser vibration measurement system, and the signal measurement point is any point on the oscillator. The vibration signal of the oscillator is recorded, and two troughs in the beat frequency envelope are found in the signal diagram. The reciprocal of the time interval between the two troughs is the magnitude of the frequency difference of the harmonic oscillator.

3. The frequency characteristic identification method according to claim 1, characterized in that, The quartz sleeve has a notch in the middle of two adjacent interdigitated electrodes for laser vibration measurement of the resonator.

4. The frequency characteristic identification method according to claim 1, characterized in that, The quartz sleeve has Z-axis movement capability.

5. The frequency characteristic identification method according to claim 1, characterized in that, The interdigitated electrodes are arranged in a comb-like pattern and have a periodic structure.

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