A mass leveling system and method for a hemispherical resonator

Abstract

The present disclosure relates to a mass leveling system and method for a hemispherical resonator, the system comprising: an excitation module for exciting the hemispherical resonator to be leveled to generate vibration; a laser interferometer comprising at least two detection probes for collecting vibration information of at least two positions of the hemispherical resonator; an ion beam etching module for etching the hemispherical resonator using an ion beam; and a control module for determining the orientation of the vibration principal axis of the hemispherical resonator and the size of frequency splitting according to the vibration information of the at least two positions of the hemispherical resonator in the vibration decay process; and controlling the ion beam etching module to etch the hemispherical resonator using the ion beam according to the orientation of the vibration principal axis of the hemispherical resonator and the size of frequency splitting, so as to realize mass leveling of the hemispherical resonator. Thus, mass leveling with higher precision and high automation can be realized without reducing the quality factor of the hemispherical resonator.

Description

Technical Field

[0001] This disclosure relates to the field of vibrating gyroscope technology, and in particular to a mass leveling system and method for a hemispherical harmonic oscillator. Background Technology

[0002] A hemispherical resonator gyroscope is an inertial sensor that measures angular rate or attitude angle. It boasts advantages such as simple structure, high accuracy, long lifespan, and high reliability, and is widely used in various scenarios including deep space exploration, satellite attitude measurement, and ship navigation. The hemispherical resonator oscillator is the core component of the hemispherical resonator gyroscope, and its performance determines the gyroscope's final performance. Fused silica glass has a low thermal expansion coefficient and advantages such as isotropy and a high quality factor, and is typically used to manufacture high-performance hemispherical resonators. To ensure high performance, the hemispherical resonator oscillator should have very small frequency fragmentation, meaning a small difference in the resonant frequencies between the two operating modes. However, fused silica is a brittle material, and factors such as current processing precision and residual stress can lead to anisotropic stiffness and uneven mass distribution in the manufactured quartz resonator oscillator, resulting in significant frequency fragmentation and causing zero-bias drift in the hemispherical resonator gyroscope. When a hemispherical harmonic oscillator vibrates, it generates two natural axes that are 45° apart, also known as principal axes. When the hemispherical harmonic oscillator vibrates along the two principal axes, the vibration frequencies are ω1 and ω2, respectively. The absolute value of the difference between the two is called frequency splitting.

[0003] In the prior art, the following schemes can be used to eliminate frequency splitting: (1) Electrostatic tuning. For example, in 2020, the National University of Defense Technology disclosed a frequency splitting elimination method based on electrostatic force tuning. It uses voltage applied to specific mode tuning electrodes to adjust the mode resonant frequency by generating electrostatic negative stiffness, thereby reducing or eliminating frequency splitting. However, the noise of the control circuit and electrodes will introduce additional zero bias error, reducing the gyroscope performance. (2) Mass leveling. This method can fundamentally eliminate frequency splitting without introducing additional tuning control structure. This method is widely used because of its good effect. There are currently many schemes. For example, in 2013, Georgia Institute of Technology disclosed a frequency splitting elimination method based on mechanical adjustment. It removes excess mass from the surface of the quartz resonator shell by mechanical grinding, so that the resonant frequencies of the two modes are close, thus completing mass leveling. However, in this method, residual stress will be generated by mechanical grinding, causing the quartz resonator to generate a subsurface defect layer, reducing the quality factor of the resonator, and ultimately reducing the gyroscope performance index. In 2015, the University of California disclosed a laser-cutting-based frequency fragmentation elimination method. This method uses a laser to cut the end face of a quartz resonator, removing excess mass to achieve mass leveling and eliminate frequency fragmentation. However, this method uses a high-energy laser to evaporate and remove material from a localized area of ​​the resonator, causing the surface temperature in the laser-irradiated area to rise sharply to thousands of degrees Celsius. After laser leveling, the temperature in this area drops sharply, leading to internal stress and increased internal friction, which in turn reduces the quality factor of the resonator. Furthermore, the relationship between the removed mass and the laser leveling position is very complex, making it extremely difficult to accurately remove the pre-calculated mass, which is insufficient for high-precision hemispherical resonator gyroscopes. In 2018, the National University of Defense Technology disclosed a chemical etching-based quartz resonator frequency fragmentation elimination method. This method uses an attitude control fixture to hold the quartz resonator and immerse it in a hydrofluoric acid solution. By establishing a linear model controlling the immersion time and the removed mass, frequency fragmentation can be effectively eliminated quantitatively. However, this method is significantly affected by external environmental factors such as solution concentration and reaction temperature changes, and therefore is only suitable for medium-precision frequency fragmentation correction. However, none of the above leveling schemes can achieve higher precision frequency splitting and tuning, that is, it is difficult to achieve high precision quality leveling, and they cannot meet the development requirements of high precision hemispherical resonant gyroscopes. Summary of the Invention

[0004] In view of this, this disclosure proposes a mass leveling system and method for hemispherical harmonic oscillators, which can achieve higher precision mass leveling with a high degree of automation, while not reducing the quality factor of the hemispherical harmonic oscillator.

[0005] According to one aspect of this disclosure, a mass leveling system for a hemispherical harmonic oscillator is provided, the system comprising: an excitation module for exciting the hemispherical harmonic oscillator to be leveled to vibrate; a laser interferometer including at least two detection probes for acquiring vibration information at at least two positions of the hemispherical harmonic oscillator, the vibration information at the at least two positions including at least two vibration displacements of the lip of the hemispherical harmonic oscillator spaced 45° apart in the circumferential direction; an ion beam etching module for etching the hemispherical harmonic oscillator using an ion beam; and a control module for: according to the laser... The interferometer collects vibration information from at least two positions of the hemispherical resonator during the vibration decay process to determine the orientation of the principal axis of vibration and the magnitude of frequency splitting of the hemispherical resonator. Based on the orientation of the principal axis of vibration and the magnitude of frequency splitting, multiple etching positions for etching the hemispherical resonator and the etching duration corresponding to each etching position are determined. Based on the multiple etching positions and the etching duration corresponding to each etching position, the ion beam etching module is controlled to use an ion beam to etch the hemispherical resonator to achieve mass leveling of the hemispherical resonator.

[0006] In one possible implementation, the ion beam etching module includes: an ion source, a neutralizer, and a movable ion beam baffle; the ion source is used to generate a positively charged ion beam; the neutralizer is used to generate a negatively charged electron beam; the electron beam generated by the neutralizer is used to neutralize the positively charged ion beam generated by the ion source, to prevent the accumulation of positive charges in the ion beam on the surface of the hemispherical resonator; the ion beam baffle includes a closed state and an open state, the closed state being used to block the ion beam from hitting the hemispherical resonator, and the open state being used to allow the ion beam to hit the hemispherical resonator; wherein, the ion beam baffle is initially in the closed state and the ion source and the neutralizer are activated, and the ion beam etching module is controlled to use an ion source based on the plurality of etching positions and the etching duration corresponding to each etching position. The sub-beam etching process for the hemispherical resonator includes: for the nth etching position among the plurality of etching positions, controlling the hemispherical resonator to move and / or rotate to a predetermined position corresponding to the nth etching position, so that the ion beam generated by the ion beam etching module can be focused on the nth etching position, 1≤n≤N, where N is the total number of the plurality of etching positions; when the hemispherical resonator has moved and / or rotated to the predetermined position corresponding to the nth etching position, controlling the ion beam baffle to move from a closed state to an open state, so that the ion beam begins to etch the nth etching position; when the ion beam has continuously etched the etching time corresponding to the nth etching position, controlling the ion beam baffle to move from an open state to a closed state, so as to stop the etching of the nth etching position.

[0007] In one possible implementation, determining the multiple etching positions to be etched on the hemispherical resonator and the etching time corresponding to each etching position based on the orientation of the principal axis of vibration of the hemispherical resonator and the magnitude of frequency fragmentation includes: determining multiple etching positions to be etched on the surface of the hemispherical resonator based on the orientation of the principal axis of vibration of the hemispherical resonator; determining the total etching time based on the magnitude of frequency fragmentation of the hemispherical resonator and the preset ion beam etching rate corresponding to the ion beam etching module; and determining the etching time corresponding to each etching position based on the number of the multiple etching positions and the total etching time.

[0008] In one possible implementation, the control module is further configured to: control the excitation module to apply an excitation signal with the same natural frequency as the hemispherical harmonic oscillator to the hemispherical harmonic oscillator to excite the hemispherical harmonic oscillator to vibrate; when the vibration amplitude of the hemispherical harmonic oscillator is stable, control the excitation module to disconnect the excitation signal so that the vibration of the hemispherical harmonic oscillator can decay freely; and control the laser interferometer to collect vibration information of the hemispherical harmonic oscillator at at least two positions during the vibration decay process.

[0009] In one possible implementation, the excitation module includes at least one set of interdigital electrodes and a high-voltage amplifier connected to each set of interdigital electrodes. The input of the high-voltage amplifier is connected to the control module and is used to amplify at least one excitation signal output by the control module and transmit the amplified excitation signal to the at least one set of interdigital electrodes to apply the amplified excitation signal to the hemispherical resonator through the at least one set of interdigital electrodes, thereby exciting the hemispherical resonator to vibrate. Each excitation signal corresponds to one set of interdigital electrodes.

[0010] In one possible implementation, the system further includes: a vacuum chamber, a displacement stage, a rotary stage, a resonator fixture, and a fixing fixture; wherein, the vacuum chamber provides a vacuum environment for the system; the displacement stage controls the horizontal and vertical movement of the hemispherical resonator to adjust the horizontal and vertical etching positions of the hemispherical resonator relative to the ion source in the ion beam etching module; the rotary stage is fixedly connected above the displacement stage and controls the rotation of the hemispherical resonator around its axis of symmetry to achieve etching at different circumferential positions of the hemispherical resonator; the resonator fixture is coaxially fixed to the rotary stage and passes through the fixing fixture to fix the hemispherical resonator above the fixing fixture; the fixing fixture is coaxially fixed to the displacement stage and fixes at least one set of interdigitated electrodes in the excitation module and at least two detection probes of the laser interferometer; wherein, the at least two detection probes are circumferentially distributed on the fixing fixture and the angle between the line connecting two adjacent detection probes and the hemispherical resonator support column is 45°.

[0011] According to another aspect of this disclosure, a method for mass leveling a hemispherical harmonic oscillator is provided, characterized in that the method includes: exciting the hemispherical harmonic oscillator to vibrate using an excitation signal with the same natural frequency as the hemispherical harmonic oscillator to be leveled; disconnecting the excitation signal when the vibration amplitude of the hemispherical harmonic oscillator is stable, so that the vibration of the hemispherical harmonic oscillator can decay freely; acquiring vibration information of the hemispherical harmonic oscillator at at least two positions during the vibration decay process, wherein the vibration information of the at least two positions includes at least two vibration displacements of the lip of the hemispherical harmonic oscillator at 45° intervals in the circumferential direction; determining the orientation of the principal axis of vibration and the magnitude of frequency splitting of the hemispherical harmonic oscillator based on the acquired vibration information of the at least two positions; determining multiple etching positions for etching the hemispherical harmonic oscillator and the etching duration corresponding to each etching position based on the orientation of the principal axis of vibration and the magnitude of frequency splitting of the hemispherical harmonic oscillator; and etching the hemispherical harmonic oscillator using an ion beam based on the multiple etching positions and the etching duration corresponding to each etching position, so as to achieve mass leveling of the hemispherical harmonic oscillator.

[0012] In one possible implementation, determining multiple etching positions for etching the hemispherical resonator and the etching duration corresponding to each etching position based on the orientation of the principal axis of vibration and the magnitude of frequency fragmentation includes: determining multiple etching positions for etching the surface of the hemispherical resonator based on the orientation of the principal axis of vibration; determining the total etching duration based on the magnitude of frequency fragmentation of the hemispherical resonator and the preset ion beam etching rate corresponding to the ion beam etching module; and determining the etching duration corresponding to each etching position based on the total number of etching positions and the total etching duration.

[0013] In one possible implementation, etching the hemispherical resonator with an ion beam based on the plurality of etching positions and the etching duration corresponding to each etching position includes: for the nth etching position among the plurality of etching positions, controlling the hemispherical resonator to move and / or rotate to a predetermined position corresponding to the nth etching position, so that the ion beam can be focused on the nth etching position, 1≤n≤N, where N is the total number of the plurality of etching positions; and when the hemispherical resonator has been moved and / or rotated to the predetermined position corresponding to the nth etching position, using the ion beam to etch the nth etching position for the etching duration corresponding to the nth etching position.

[0014] In one possible implementation, after etching the hemispherical resonator with an ion beam according to the plurality of etching positions and the etching duration corresponding to each etching position, the method further includes: redetermining the orientation of the principal axis of vibration of the hemispherical resonator and the magnitude of the frequency split, and determining whether the redetermined magnitude of the frequency split meets a preset index; if the redetermined magnitude of the frequency split does not meet the preset index, etching the hemispherical resonator again with an ion beam according to the redetermined orientation of the principal axis of vibration and the magnitude of the frequency split.

[0015] According to embodiments of this disclosure, vibration information of at least two positions of a hemispherical resonator during vibration decay can be collected by a laser vibrometer with at least two detection probes. This allows for the determination of the orientation of the main vibration axis and the magnitude of frequency fragmentation with higher accuracy. Consequently, multiple etching positions and etching durations can be determined, and etching can be performed using an ion beam. This enables higher precision quality leveling with a high degree of automation, without reducing the quality factor of the hemispherical resonator.

[0016] Other features and aspects of this disclosure will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0017] The accompanying drawings, which are included in and form part of this specification, illustrate exemplary embodiments, features, and aspects of this disclosure together with the specification and serve to explain the principles of this disclosure.

[0018] Figure 1 A block diagram of a mass leveling system for a hemispherical harmonic oscillator according to an embodiment of the present disclosure is shown.

[0019] Figure 2 This diagram illustrates the distribution of two sets of interdigitated electrodes within an excitation module according to an embodiment of the present disclosure.

[0020] Figures 3(a) and 3(b) show schematic diagrams of the structure of an ion beam etching module according to an embodiment of the present disclosure.

[0021] Figure 4 A schematic diagram of a quality leveling system according to an embodiment of the present disclosure is shown.

[0022] Figure 5 A schematic diagram of the layout of a fixture according to an embodiment of the present disclosure is shown.

[0023] Figure 6 This diagram illustrates a process for determining the orientation and frequency splitting magnitude of a vibration principal axis according to an embodiment of the present disclosure.

[0024] Figure 7 A schematic diagram of an etching location according to an embodiment of the present disclosure is shown.

[0025] Figure 8 A flowchart is shown for a mass leveling method for a hemispherical harmonic oscillator according to an embodiment of the present disclosure. Detailed Implementation

[0026] Various exemplary embodiments, features, and aspects of this disclosure will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0027] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0028] Furthermore, to better illustrate this disclosure, numerous specific details are set forth in the following detailed description. Those skilled in the art will understand that this disclosure can be practiced without certain specific details. In some instances, methods, means, components, and circuits well known to those skilled in the art have not been described in detail in order to highlight the main points of this disclosure.

[0029] As mentioned above, existing balancing schemes are unable to achieve higher precision frequency splitting correction, i.e., they are unable to achieve high-precision mass balancing, thus failing to meet the development requirements of high-precision hemispherical resonator gyroscopes. In view of this, this disclosure proposes a mass balancing system and method for hemispherical resonators, which can achieve mass balancing of the hemispherical resonator, thereby reducing frequency splitting. It has advantages such as not reducing the quality factor of the hemispherical resonator, high balancing accuracy, and high automation, and has broad application prospects in the field of inertial navigation. Specifically, the mass balancing system and method proposed in this disclosure can accurately determine the orientation of the hemispherical resonator's principal axis of vibration and the magnitude of frequency splitting. Then, based on the relationship between ion beam etching time and frequency splitting, the ion beam is used to remove unbalanced mass at the position of the hemispherical resonator's heavy axis (i.e., the low-frequency principal axis of vibration), achieving mass balancing of the hemispherical resonator, reducing frequency splitting, and thus reducing the zero-bias drift problem of the hemispherical resonator gyroscope.

[0030] The following is passed Figures 1 to 7 The quality leveling system of the present disclosure will be described in detail.

[0031] Figure 1 A block diagram of a mass leveling system for a hemispherical harmonic oscillator according to an embodiment of the present disclosure is shown. Figure 1 As shown, the system includes:

[0032] Excitation module 11 is used to excite the hemispherical harmonic oscillator to be leveled to vibrate;

[0033] The laser interferometer 12 includes at least two detection probes for acquiring vibration information at at least two positions of the hemispherical harmonic oscillator. The vibration information at the at least two positions includes at least two vibration displacements of the lip of the hemispherical harmonic oscillator in the circumferential direction with a spacing of 45°.

[0034] Ion beam etching module 13 is used to etch a hemispherical harmonic oscillator using an ion beam;

[0035] The control module 14 is used to: determine the orientation of the principal axis of vibration and the magnitude of frequency splitting of the hemispherical harmonic oscillator based on the vibration information of at least two positions of the hemispherical harmonic oscillator during the vibration decay process collected by the laser interferometer 12; determine multiple etching positions to be etched on the hemispherical harmonic oscillator and the etching time corresponding to each etching position based on the orientation of the principal axis of vibration and the magnitude of frequency splitting of the hemispherical harmonic oscillator; and control the ion beam etching module to use an ion beam to etch the hemispherical harmonic oscillator based on the multiple etching positions and the etching time corresponding to each etching position, so as to achieve mass leveling of the hemispherical harmonic oscillator.

[0036] Optionally, the excitation module 11 may include a striking device to excite the hemispherical resonator by striking it, thereby causing the hemispherical resonator to vibrate. Alternatively, the excitation module 11 may also apply an AC voltage signal, or a sinusoidal excitation signal, to the hemispherical resonator to vibrate. In one possible implementation, to achieve vibration of the hemispherical resonator by applying a sinusoidal excitation signal, the excitation module 11 may include at least one set of interdigital electrodes 111 and a high-voltage amplifier 112 connected to each set of interdigital electrodes 111. The input of the high-voltage amplifier 112 is connected to the control module 14, amplifying at least one excitation signal output by the control module 14 and transmitting the amplified excitation signal to the at least one set of interdigital electrodes 111, thereby applying the amplified excitation signal to the hemispherical resonator and exciting it to vibrate. Each excitation signal corresponds to one set of interdigital electrodes. This method allows for more precise control of the vibration frequency and excitation direction of the hemispherical harmonic oscillator by controlling the frequency and direction of the excitation signal.

[0037] For example, Figure 2 The diagram illustrates the distribution of two sets of interdigitated electrodes within an excitation module, such as... Figure 2 As shown, each set of interdigital electrodes includes two interdigital electrodes connected to each other diagonally at 180°. 111_a1 and 111_a2 form one set of interdigital electrodes, and 111_b1 and 111_b2 form the other set. The two sets of interdigital electrodes are spaced 45° apart, that is, 111_a1 and 111_b2 are spaced 45° apart, and 111_a2 and 111_b2 are spaced 45° apart. The input terminals (a1 and a2, b1 and b2) of the two sets of interdigital electrodes are connected to the output terminals of the high-voltage amplifier. Excitation signals can be applied to the two excitation channels (each corresponding to one set of interdigital electrodes) to excite the hemispherical resonator to vibrate in two different directions. Alternatively, excitation signals of different amplitudes can be applied to the two excitation channels simultaneously. Different applied excitation signals can generate driving forces at different angular positions, thereby enabling the hemispherical resonator to vibrate at different angular positions. It should be understood that... Figure 2 The distribution of the interdigitated electrodes shown is one possible implementation provided by the embodiments of this disclosure. In fact, those skilled in the art can set the number and distribution of the interdigitated electrodes included in the excitation module 11 according to actual needs. For example, only one set of interdigitated electrodes can be set, or the two sets of interdigitated electrodes can be distributed at a 90° interval. That is, in order to achieve multi-angle excitation, different forms of interdigitated electrodes can be used, etc. The embodiments of this disclosure do not limit this.

[0038] In practical applications, the laser interferometer 12 can be any instrument known in the art for measuring multi-channel vibration information (i.e., vibration signals), such as a fiber laser interferometer. It should be understood that this laser interferometer can also be understood as a laser vibration meter. This disclosure does not limit the type or model of the laser interferometer.

[0039] To facilitate the acquisition of at least two 45° intervals between vibration displacements of the hemispherical harmonic oscillator lip along its circumferential direction using at least two detection probes of the laser interferometer 12, the at least two detection probes of the laser interferometer can be distributed along the circumference of the hemispherical harmonic oscillator and form an angle of 45° with the line connecting the hemispherical harmonic oscillator support column. The reason for designing the measurement at two 45° intervals is determined by the vibration law of the harmonic oscillator. When the harmonic oscillator vibrates, there are four antinodes (maximum amplitude) and four nodal points (zero amplitude). To identify the orientation of the principal axis of vibration, the detection probes are designed to be distributed at 45° intervals.

[0040] The ion beam etching module 13 uses an ion beam to etch the hemispherical harmonic oscillator. This involves utilizing the sputtering effect of the ion beam interacting with the oscillator surface to remove unbalanced mass (i.e., surface material), or, in other words, using kinetic-energy-carrying ions to bombard the atoms in the material. During the collision, the ions transfer energy to the atoms in the harmonic oscillator material. When the energy of an atom on the material surface in a direction perpendicular to the surface exceeds its surface binding energy, the atom detaches from the material. The mass removed by ion beam etching is approximately linearly related to the leveling time, allowing the removed mass to be controlled in the microgram range, thus achieving very high leveling accuracy. Furthermore, ion beam leveling does not produce significant thermal effects, which helps maintain a good quality factor for the hemispherical harmonic oscillator.

[0041] In one possible implementation, as shown in Figures 3(a) and 3(b), the ion beam etching module 13 may include: an ion source 131, a neutralizer 132, and a movable ion beam baffle 133; the ion source 131 is used to generate a positively charged ion beam to remove the unbalanced mass on the surface of the hemispherical harmonic oscillator. Optionally, since argon ions generated by argon gas as a gas source have high kinetic energy and are suitable for etching, the ion beam generated by the ion source 131 may be an argon ion beam; the neutralizer 132 is used to generate a negatively charged electron beam; the electron beam generated by the neutralizer 132 is used to neutralize ions. The positively charged ion beam generated by the ion source 131 is used to prevent the accumulation of positive charges on the surface of the hemispherical harmonic oscillator, which would affect the ion beam etching effect. The ion beam baffle 133 includes a closed state shown in Figure 3(a) and an open state shown in Figure 3(b). The closed state shown in Figure 3(a) is used to block the ion beam from hitting the hemispherical harmonic oscillator, and the open state shown in Figure 3(b) is used to allow the ion beam to hit the hemispherical harmonic oscillator. It should be understood that by controlling the duration between the closed and open states of the ion beam baffle 133, the etching duration of the ion beam on the hemispherical harmonic oscillator can be controlled. In particular, the ion beam baffle 133 can more accurately control the etching duration of the ion beam on the hemispherical harmonic oscillator. This is because the ion source and neutralizer require a certain stabilization time from startup to beam stabilization. Especially when etching multiple positions of the hemispherical harmonic oscillator is required, the ion beam baffle can be used without frequently starting the ion source and neutralizer, which is also beneficial to the stability of the etching rate.

[0042] The positively charged ion beam generated by the ion source 131 can be a stable and controllable ion beam, and the negatively charged electron beam generated by the neutralizer 132 can be a stable and controllable electron beam. In practical applications, the ion beam baffle 133 can be fixed to the actuator by a connecting shaft. The control module 14 can control the actuator to move according to the ion beam etching time, thereby driving the ion beam baffle 133 to move, that is, controlling the change of the ion beam baffle 133 between the closed state and the open state.

[0043] Figure 4 This diagram illustrates the structure of a quality leveling system according to an embodiment of the present disclosure, as shown below. Figure 4 As shown, the system also includes: a vacuum chamber 15, a displacement stage 16, a rotary stage 17, a resonator fixture 18, and a fixed fixture 19; wherein, the vacuum chamber 15 is used to provide a vacuum environment for the system;

[0044] The displacement stage 16 is used to control the horizontal and vertical movement of the hemispherical resonator 00 to adjust the horizontal position and vertical etching position of the hemispherical resonator 00 relative to the ion source 131 in the ion beam etching module. That is, to adjust the spatial position between the fixed fixture 19 and the hemispherical resonator 00 relative to the ion source 131, so as to ensure that the focus of the ion beam falls on the outer surface near the lip of the hemispherical resonator 00. At the same time, it can also etch different etching positions in the vertical direction.

[0045] The rotary table 17 is fixedly connected above the displacement table 16 and is used to control the rotation of the hemispherical resonator 00 around the axis of symmetry so as to achieve etching of different etching positions of the hemispherical resonator 00 in the circumferential direction.

[0046] The resonator clamp 18 is coaxially fixed to the rotary table 17 and passes through the fixed fixture 19. It is used to fix the hemispherical resonator 00 above the fixed fixture 19, that is, to achieve the clamping and fixing of the hemispherical resonator.

[0047] The fixed fixture 19 is coaxially fixed to the displacement stage 17 and is used to fix at least one set of interdigital electrodes in the excitation module 11 and at least two detection probes of the laser interferometer 12; wherein, at least two detection probes are circumferentially distributed on the fixed fixture 17 and the angle between the line connecting two adjacent detection probes and the hemispherical resonator support column is 45°.

[0048] In practical applications, the vacuum chamber 15 is used to generate the vacuum environment required for the operation of the ion source 131 and the neutralizer 132. Several flange interfaces of specific specifications can be left on the outer wall of the vacuum chamber for installing the ion source 131, the neutralizer 132, the glass observation window, the vacuum feedthrough, etc.

[0049] The displacement stage 16 and the rotation stage 17 can be used to control the spatial position of the hemispherical harmonic oscillator to move and rotate. This is beneficial because the horizontal movement of the displacement stage 16 can make the focus of the ion beam fall on the outer surface near the lip of the harmonic oscillator. The vertical movement of the displacement stage 16 can remove mass from different latitudes of the harmonic oscillator, and the rotation of the rotation stage 17 can remove mass from different circumferential positions of the harmonic oscillator.

[0050] The interdigitated electrodes fixedly mounted on the fixture 19 can be connected to the output of the high-voltage amplifier 112 in the excitation module 11 via a vacuum feedthrough, thereby enabling excitation of at least one channel of the hemispherical resonator. The high-voltage amplifier 112 amplifies the AC voltage signal (i.e., the excitation signal) generated by the control module 14, with an adjustable amplification factor. The input of the high-voltage amplifier 112 is connected to the DA output (which converts digital signals into analog signals) of the control module 14, and the output of the high-voltage amplifier 112 is connected to the interdigitated electrodes 111 via a vacuum feedthrough.

[0051] The laser interferometer 12 is used to measure the vibration information of the resonator. The laser interferometer 12 has at least two detection probes 121 (i.e., detection channels) for synchronously detecting the vibration information of the resonator lip at a circumferential interval of 45° (i.e., at least two vibration displacements at a 45° interval). In other words, the detection channel is the measurement channel of the laser interferometer, used to synchronously measure the vibration displacement of the hemispherical resonator at two positions. The input end of the laser interferometer 12 is connected to at least two detection probes at a 45° interval on the fixed fixture 19 in the vacuum chamber 15 through a vacuum feedthrough. The output end of the laser interferometer 12 is connected to the control module 14 through an adapter.

[0052] For example, Figure 5 This diagram illustrates the layout of a fixed tooling provided in an embodiment of the present disclosure, as shown below. Figure 5 As shown, a set of interdigital electrodes 111 and two detection probes 121 are provided on the fixed fixture 19. The angle between the line connecting the two detection probes 121 and the support shaft of the hemispherical resonator 00 is 45°. The support shaft of the hemispherical resonator 00 can be clamped by the resonator clamp 18 to fix the hemispherical resonator 00 above the fixed fixture 19, so that the interdigital electrodes 11 can apply excitation signals to the hemispherical resonator, and the detection probes 121 can detect the vibration information of the hemispherical resonator.

[0053] It should be understood that the above Figure 4 The system structure shown is one possible implementation provided by the embodiments of this disclosure. In fact, those skilled in the art can design the hardware structure and components included in the system according to actual needs. For example, vibration isolation air floating platforms and cabinet groups can also be set up. The embodiments of this disclosure do not limit this.

[0054] In practical applications, the control module 14 may employ a device known in the art that has computational processing and control capabilities. For example, the control module 14 may employ one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSP devices, DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), general-purpose processors, controllers, microcontrollers, microprocessors, other electronic units for performing the functions required thereto, or combinations thereof. This disclosure does not limit the scope of the embodiments.

[0055] As described above, the control module 14 determines the orientation of the principal axis of vibration and the magnitude of frequency splitting of the hemispherical harmonic oscillator based on the vibration information of at least two positions of the hemispherical harmonic oscillator during the vibration decay process acquired by the laser interferometer. Thus, the control module 14 can first control the excitation module 11 to excite the hemispherical harmonic oscillator to vibrate, for example by striking the hemispherical harmonic oscillator to produce vibration, or by applying an excitation signal to make the hemispherical harmonic oscillator vibrate and then disconnecting the excitation signal to allow the vibration of the hemispherical harmonic oscillator to decay freely. Then, the control module 14 controls the laser interferometer 12 to acquire the vibration information of at least two positions of the hemispherical harmonic oscillator during the vibration decay process.

[0056] Specifically, regarding the method of driving the hemispherical harmonic oscillator to vibrate by applying an excitation signal, in order to better drive the hemispherical harmonic oscillator to vibrate, the control module 14 is further configured to: control the excitation module 11 to apply an excitation signal with the same natural frequency as the hemispherical harmonic oscillator to excite the hemispherical harmonic oscillator to vibrate; when the vibration amplitude of the hemispherical harmonic oscillator is stable, control the excitation module 11 to disconnect the excitation signal to allow the vibration of the hemispherical harmonic oscillator to decay freely; and control the laser interferometer 12 to collect vibration information from at least two positions of the hemispherical harmonic oscillator during the vibration decay process. In this way, the hemispherical harmonic oscillator can produce significant vibration, making it easier to collect vibration information with a good signal-to-noise ratio.

[0057] It is known that the closer the frequency of the excitation signal applied to the hemispherical harmonic oscillator is to the natural frequency of the hemispherical harmonic oscillator, the greater the vibration amplitude of the hemispherical harmonic oscillator. Therefore, it is easier to drive the hemispherical harmonic oscillator to produce obvious vibration by using an excitation signal with the same natural frequency as the hemispherical harmonic oscillator, or a sinusoidal excitation signal with the same natural frequency after being amplified by a high-voltage amplifier (i.e., an AC voltage signal).

[0058] In practical applications, the natural frequency of the hemispherical harmonic oscillator can be determined by frequency sweeping. Then, a sinusoidal excitation signal with the same natural frequency is used to excite the hemispherical harmonic oscillator to vibrate. When the vibration amplitude stabilizes, the excitation signal is disconnected. For example, the stability of the vibration amplitude of the hemispherical harmonic oscillator can be determined visually using an oscilloscope or by measuring the vibration amplitude detected by the laser interferometer 12. Then, the laser interferometer 12 is controlled to collect vibration information of the hemispherical harmonic oscillator in real time during the free decay process. Vibration information can be collected for a specified duration (e.g., 100 seconds, 300 seconds, etc.) from the beginning of the decay process because the vibration amplitude is larger and the signal-to-noise ratio is higher in the early stage of decay, which is beneficial for vibration detection. Then, the vibration information collected by the laser interferometer is synchronously demodulated and processed, that is, the frequency splitting magnitude and the orientation of the principal axis of vibration are identified using a high-precision identification algorithm for the harmonic oscillator performance parameters.

[0059] It is known that the natural frequency of a hemispherical resonator is related to the material, the diameter of the resonator, and the wall thickness, and can be obtained through theoretical calculation formulas. However, during the manufacturing process of the hemispherical resonator, there are manufacturing errors, and the actual natural frequency may deviate from the theoretical value. Therefore, the true natural frequency of the hemispherical resonator can be measured by frequency sweep. Specifically, a frequency sweep can be performed by setting a frequency range, that is, setting an upper and lower frequency limit based on the theoretical value. Excitation signals are applied to the hemispherical resonator in sequence from the lower frequency limit to the upper frequency limit. Based on the vibration amplitude during the frequency sweep process, a reference frequency that is approximately close to the natural frequency is determined (that is, the frequency at which the vibration amplitude is the largest is used as the reference frequency). Then, the excitation signal with the reference frequency (that is, the AC voltage signal) is used to excite the hemispherical resonator to vibrate to a certain amplitude. After the excitation signal is disconnected, the hemispherical resonator is allowed to decay freely. By measuring the periodic change law of the vibration signal during the free decay process, the natural frequency can be calculated.

[0060] The natural frequency is the specific frequency at which an object vibrates under external excitation, determined solely by the object's inherent properties. It is also called the natural frequency. When an object vibrates freely, its displacement changes with time according to a sine or cosine law. The frequency of the vibration depends only on the object's inherent characteristics, such as mass, shape, and material, and is independent of external excitation; it is an inherent property of the object. In other words, a hemispherical harmonic oscillator undergoing simple harmonic motion without external force has a period or frequency independent of amplitude, determined solely by the oscillator's own properties. The vibration produced under these conditions is called natural vibration, and the frequency of this natural vibration is called the natural frequency.

[0061] Figure 6 A schematic diagram illustrating a process for determining the orientation and frequency fragmentation magnitude of a vibration principal axis according to an embodiment of the present disclosure is shown, as follows. Figure 6 As shown, after the hemispherical harmonic oscillator is excited to vibrate until the amplitude stabilizes, the excitation signal is disconnected to allow the hemispherical harmonic oscillator to decay freely, and two vibration information signals (i.e., two vibration displacements x and y) spaced 45° apart are collected. These two vibration displacements x and y can be understood as generalized displacements under two vibration modes. Then, the reference frequency ω is used to... r Demodulate the two vibration signals (close to the natural frequency ω0) to obtain four demodulated quantities x. c ,x s ,y c ,y s , where x c ,x s These are the displacement components of vibration information x that are in phase with the excitation signal and the displacement components that are orthogonal to the excitation signal, respectively. c ,y sThese are the displacement components of the vibration information y that are in phase with the excitation signal and the displacement components that are orthogonal to the phase, respectively. The identification algorithm utilizes the demodulated quantity (i.e., x and y) corresponding to the vibration information (i.e., x) collected during the free vibration process. c ,x s ,y c ,y s ), calculate the frequency difference Δω (i.e., angular frequency difference) and the azimuth θ of the principal frequency axis. ω Where Δω represents frequency decomposition, and the orientation of the principal axis of vibration is 0.5θ. ω .

[0062] In practical applications, the basic idea of ​​the identification algorithm is to establish a dynamic equation for the demodulated quantity containing vibration asymmetry error parameters, and then select a suitable identification algorithm to identify the parameters using demodulated quantity observation data of the free vibration process. For example, taking two vibration information channels as an example, vibration displacements x and y and demodulated quantity x c ,x s ,y c ,y s The following relationship exists, as shown in formula (1):

[0063]

[0064] Where, ω r Here, t is the reference frequency, and t is the change over time.

[0065] Substituting the above formula (1) into the following formula (2), we get the free vibration equation of the hemispherical harmonic oscillator:

[0066]

[0067] in, These represent the second derivatives (i.e., accelerations) of x and y, respectively. Let x and y represent the first derivatives (i.e., velocities), τ0 be the average decay time constant, Δ(1 / τ) be the damping difference, and θ be the first derivatives (i.e., velocities). τ Let θ be the orientation of the damping principal axis, γ be the angular gain coefficient, Ω be the angular velocity of the hemispherical harmonic oscillator, ω0 be the natural frequency (i.e., the natural angular frequency), Δω be the angular frequency difference, i.e., frequency fragmentation, and θ be the frequency response. ω The frequency axis is the main axis.

[0068] Then, using the averaging method, the above formula (2) can be derived to obtain the dynamic equation of the demodulated quantity under free vibration conditions shown in formula (3):

[0069]

[0070] in, They represent x respectively c y c xs y s The first derivative, w0=ω0-ω r w c =Δωcos4θ ω w s =Δωsin4θ ω . d a This represents the Coriolis force, the value of which is related to the angular velocity Ω relative to inertial space. z Regarding the hemispherical harmonic oscillator, d a ≈1.108Ω z Theoretically, w a =0, when there is a detection gain error, there may be an equivalent w. a The case where ≠0.

[0071] After obtaining the demodulated sample using the above formula (1), the parameters in the identification equation shown in the above formula (3) can be solved using the linear least squares method or the nonlinear least squares method. That is, the magnitude of the frequency split Δω and the orientation θ of the frequency principal axis can be obtained. ω ,in, This allows us to determine the orientation of the principal axis of vibration:

[0072] After obtaining the orientation of the principal axis of vibration of the hemispherical harmonic oscillator and the magnitude of frequency fragmentation, multiple etching positions for etching the hemispherical harmonic oscillator and the etching time corresponding to each etching position can be determined based on the orientation of the principal axis of vibration of the hemispherical harmonic oscillator and the magnitude of frequency fragmentation. Specifically, multiple etching positions to be etched on the surface of the hemispherical harmonic oscillator can be determined based on the orientation of the principal axis of vibration of the hemispherical harmonic oscillator; the total etching time can be determined based on the magnitude of frequency fragmentation of the hemispherical harmonic oscillator and the preset ion beam etching rate corresponding to the ion beam etching module; and the etching time corresponding to each etching position can be determined based on the number of etching positions and the total etching time.

[0073] The orientation of the principal axis of vibration reflects the distribution of the unbalanced mass of the hemispherical harmonic oscillator. The unbalanced mass is distributed along the low-frequency axis (i.e., the heavy axis). Removing the corresponding unbalanced mass along the heavy axis achieves the leveling purpose. The orientation of the principal axis of vibration calculated above is also one of the orientations of the heavy axis. The orientations of the other three heavy axes can be expressed as follows: This allows us to view from four axes of gravity. One or more orientations can be selected as etching locations to etch away surface mass. For example, all four orientations can be selected as etching locations, which can average the total mass to be etched away, making the mass etching of the hemispherical harmonic oscillator more even. Figure 7A schematic diagram of an etching location is shown, such as... Figure 7 As shown, the acquisition position of a certain vibration displacement x (i.e., the position of the detection probe corresponding to vibration displacement x) can be taken as the 0° azimuth, and the azimuth of the main vibration axis can be obtained based on this. The location is used as an etching location. These are the other three etching locations. Of course, the etching location can also be determined by using the sampling location of the vibration displacement y as the 0° orientation, and this embodiment does not limit this.

[0074] The preset ion beam etching rate corresponding to the ion beam etching module 13 represents the mass that the ion beam etching module 13 can etch within a unit time. In other words, the preset ion beam etching rate can represent the relationship between the pre-calibrated etching time and the removed mass. Since the correspondence between frequency fragmentation and etching mass is also known, after knowing the preset ion beam etching rate of the ion beam etching module 13, the rate of decrease of frequency fragmentation within a unit time can be obtained. Then, the calculated magnitude of the frequency fragmentation of the hemispherical harmonic oscillator can be divided by the rate of decrease of frequency fragmentation within a unit time to obtain the total etching time. This total etching time represents the total mass to be etched away. Then, the total etching time can be divided by the total number of etching positions to obtain the etching time corresponding to each etching position. This is equivalent to distributing the total etching mass evenly to multiple etching positions for etching. For example, the total etching time can be divided by 4 to obtain the above... Figure 7 The etching durations corresponding to the four etching positions shown can reflect the mass to be etched away at each etching position. This can make the mass etching of the hemispherical harmonic oscillator more balanced after etching, which is beneficial to improving the mass leveling effect.

[0075] As described above, at least two detection channels can be used to collect at least two vibration information. Therefore, the orientation and frequency split of the vibration main shaft can be determined by referring to the identification equation shown in the above formula (3) based on the demodulation amount of at least two vibration information. For example, the orientation and frequency split of the vibration main shaft can be determined by the vibration information of each pair of adjacent 45° in the at least two vibration information, and then the etching position and etching time can be determined.

[0076] As described above, the ion beam baffle 133 includes a closed state and an open state. The closed state is used to block the ion beam from hitting the hemispherical resonator, and the open state is used to allow the ion beam to hit the hemispherical resonator. By controlling the duration between the closed and open states of the ion beam baffle, the etching duration of the ion beam on the hemispherical resonator can be controlled. Based on this, in one possible implementation, before using the ion beam etching module 13 to etch the hemispherical resonator, the ion beam baffle 133 can be initially controlled to be in the closed state, and the ion source 131 and the neutralizer 132 can be activated, that is, the ion source 131 and the neutralizer 132 can be activated in advance. The above-mentioned control of the ion beam etching module 13 to use the ion beam to etch the hemispherical resonator according to multiple etching positions and the etching duration corresponding to each etching position includes:

[0077] For the nth etching position among multiple etching positions, the hemispherical harmonic oscillator is controlled to move and / or rotate to the predetermined position corresponding to the nth etching position, so that the ion beam generated by the ion beam etching module 13 can be focused at the nth etching position, 1≤n≤N, where N is the total number of multiple etching positions;

[0078] When the hemispherical harmonic oscillator has been moved and / or rotated to the predetermined position corresponding to the nth etching position, the ion beam baffle 133 is controlled to move from the closed state to the open state so that the ion beam can start etching the nth etching position.

[0079] When the ion beam has been etching the nth etching position for the specified etching time, the ion beam baffle 133 is controlled to move from the open state to the closed state to stop etching the nth etching position.

[0080] As described above, the hemispherical resonator can be moved horizontally and vertically by the moving stage 16, and rotated by the rotating stage 17. Thus, based on the diameter of the hemispherical resonator and the focal length of the ion beam, the moving stage 17 is first moved so that the focus of the ion beam falls on the outer surface near the lip of the hemispherical resonator. Then, based on the first etching position and the spatial position of the ion source 131, the rotating stage 17 is rotated so that the focus of the ion beam falls on the first etching position. That is, the hemispherical resonator is moved and rotated to the predetermined position corresponding to the first etching position. After etching the first etching position for the corresponding etching time, the rotating stage 17 can be sequentially controlled to rotate the hemispherical resonator by 90° so that the focus falls on the second etching position. That is, the hemispherical resonator is rotated to the predetermined position corresponding to the second etching position, thereby etching the second etching position. This process is repeated until all etching positions are etched.

[0081] In practical applications, after completing one round of mass leveling using the aforementioned mass leveling system, the system can be used again to redetermine the orientation of the principal axis of vibration and the magnitude of the frequency break, and to determine whether the redetermined magnitude of the frequency break meets the preset specifications. If the redetermined magnitude of the frequency break does not meet the preset specifications, the system is used to perform mass leveling on the hemispherical resonator again based on the redetermined orientation of the principal axis of vibration and the magnitude of the frequency break, until the magnitude of the frequency break of the leveled hemispherical resonator meets the preset specifications. The preset specifications can be customized by technicians according to actual needs. Hemispherical resonators with a frequency break less than the preset specifications are considered qualified, thus allowing the hemispherical resonators to meet different mass leveling requirements.

[0082] According to the quality leveling system of this disclosure, the vibration information of a hemispherical harmonic oscillator at multiple positions during the vibration decay process can be collected by a laser vibrometer with multiple detection probes to determine the orientation of the main vibration axis and the magnitude of frequency fragmentation with higher accuracy. Then, the etching position and etching time can be determined, and ion beam etching can be performed. This system can achieve higher accuracy quality leveling with a high degree of automation, and will not reduce the quality factor of the hemispherical harmonic oscillator.

[0083] Based on the above-described quality leveling system, embodiments of this disclosure also provide, for example... Figure 8 The flowchart shown illustrates a mass leveling method for a hemispherical harmonic oscillator. This method can be applied to the aforementioned mass leveling system, such as... Figure 8 As shown, the method includes:

[0084] Step S801: Using an excitation signal with the same natural frequency as the hemispherical harmonic oscillator to be leveled, the hemispherical harmonic oscillator is excited to vibrate. When the vibration amplitude of the hemispherical harmonic oscillator is stable, the excitation signal is disconnected so that the vibration of the hemispherical harmonic oscillator can decay freely.

[0085] Step S802: Collect vibration information of the hemispherical harmonic oscillator at at least two positions during the vibration decay process, wherein the vibration information of the at least two positions includes at least two vibration displacements of the lip of the hemispherical harmonic oscillator at a circumferential distance of 45°.

[0086] Step S803: Based on the vibration information collected from the at least two locations, determine the orientation of the principal axis of vibration of the hemispherical harmonic oscillator and the magnitude of the frequency split.

[0087] Step S804: Based on the orientation of the principal axis of vibration of the hemispherical harmonic oscillator and the magnitude of frequency splitting, determine multiple etching positions for etching the hemispherical harmonic oscillator and the etching duration corresponding to each etching position.

[0088] Step S805: Based on the plurality of etching positions and the etching duration corresponding to each etching position, an ion beam is used to etch the hemispherical harmonic oscillator to achieve mass leveling of the hemispherical harmonic oscillator.

[0089] In step S801, the excitation module 11 in the aforementioned mass balancing system can be controlled by the control module 14 to excite the hemispherical harmonic oscillator to vibrate using an excitation signal with the same natural frequency as the hemispherical harmonic oscillator to be balanced. Once the vibration amplitude of the hemispherical harmonic oscillator is stable, the excitation signal is disconnected to allow the vibration of the hemispherical harmonic oscillator to decay freely. In step S802, the laser interferometer 12 in the aforementioned mass balancing system can be controlled by the control module 14 to collect vibration information from at least two positions of the hemispherical harmonic oscillator during the vibration decay process. Then, the control module 14 can execute steps S803 to S804, and control the ion beam etching module 13 to etch the hemispherical harmonic oscillator using an ion beam according to the multiple etching positions and the etching duration corresponding to each etching position, thereby achieving mass balancing of the hemispherical harmonic oscillator. The specific implementation methods of each step can be referred to the relevant descriptions of the various modules in the aforementioned mass balancing system, and will not be elaborated here.

[0090] In one possible implementation, determining multiple etching positions and the etching duration corresponding to each etching position based on the orientation of the hemispherical resonator's principal axis of vibration and the magnitude of frequency fragmentation includes: determining multiple etching positions on the surface of the hemispherical resonator based on the orientation of the principal axis of vibration; determining the total etching duration based on the magnitude of frequency fragmentation of the hemispherical resonator and the preset ion beam etching rate corresponding to the ion beam etching module; and determining the etching duration corresponding to each etching position based on the total number of etching positions and the total etching duration. The specific implementation of determining multiple etching positions and the etching duration corresponding to each etching position in the control module 14 of the aforementioned quality leveling system can be referenced, and will not be elaborated upon here.

[0091] In one possible implementation, etching the hemispherical resonator with an ion beam based on the plurality of etching positions and the etching duration corresponding to each etching position includes: for the nth etching position among the plurality of etching positions, controlling the hemispherical resonator to move and / or rotate to a predetermined position corresponding to the nth etching position, so that the ion beam can be focused on the nth etching position, 1≤n≤N, where N is the total number of the plurality of etching positions; after the hemispherical resonator has been moved and / or rotated to the predetermined position corresponding to the nth etching position, using the ion beam to etch the nth etching position for the etching duration corresponding to the nth etching position. The specific implementation method of using the ion beam etching module 13 in the above-described quality leveling system to perform etching for each etching position for a corresponding etching duration can be referred to, and will not be elaborated here.

[0092] In one possible implementation, after etching the hemispherical resonator with an ion beam according to the plurality of etching positions and the etching duration corresponding to each etching position, the method further includes: redetermining the orientation of the principal axis of vibration of the hemispherical resonator and the magnitude of the frequency split, and determining whether the redetermined magnitude of the frequency split meets a preset index; if the redetermined magnitude of the frequency split does not meet the preset index, etching the hemispherical resonator again with an ion beam according to the redetermined orientation of the principal axis of vibration and the magnitude of the frequency split.

[0093] After completing one round of quality balancing according to steps S801 to S805, steps S801 to S803 can be repeated on the balancing hemispherical resonator to redetermine the orientation of the principal axis of vibration and the magnitude of the frequency split. If the redetermined frequency split meets the preset index, the quality balancing of the hemispherical resonator is completed, and a qualified hemispherical resonator is obtained. If the redetermined frequency split does not meet the preset index, steps S804 to S805 are repeated according to the redetermined orientation of the principal axis of vibration and the magnitude of the frequency split, that is, the hemispherical resonator is etched again. It should be understood that the above steps S801 to S805 can be executed multiple times until the frequency split of the hemispherical resonator meets the preset index.

[0094] According to the mass leveling method of this disclosure, the orientation of the main vibration axis and the magnitude of frequency splitting can be determined with higher accuracy by utilizing the vibration information of multiple positions of the hemispherical harmonic oscillator during the vibration decay process. This allows for the determination of multiple etching positions and etching durations, and the use of an ion beam for etching. This method can achieve higher precision mass leveling with a high degree of automation, while not reducing the quality factor of the hemispherical harmonic oscillator.

[0095] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems and methods according to various embodiments of the present disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of an instruction containing one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than those shown in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0096] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A mass leveling system for a hemispherical harmonic oscillator, characterized in that, The system includes: The excitation module is used to excite the hemispherical harmonic oscillator to be leveled to vibrate. A laser interferometer includes at least two detection probes, which are used to collect vibration information at at least two positions of the hemispherical harmonic oscillator. The vibration information at the at least two positions includes at least two vibration displacements of the lip of the hemispherical harmonic oscillator in the circumferential direction with a spacing of 45°. An ion beam etching module is used to etch the hemispherical harmonic oscillator using an ion beam; The control module is configured to: determine the orientation of the principal axis of vibration and the magnitude of frequency splitting of the hemispherical resonator based on the vibration information of at least two positions of the hemispherical resonator during the vibration decay process acquired by the laser interferometer; determine multiple etching positions for etching the hemispherical resonator and the etching duration corresponding to each etching position based on the orientation of the principal axis of vibration and the magnitude of frequency splitting of the hemispherical resonator; and control the ion beam etching module to use an ion beam to etch the hemispherical resonator based on the multiple etching positions and the etching duration corresponding to each etching position, so as to achieve mass leveling of the hemispherical resonator. The ion beam etching module includes an ion source, a neutralizer, and a movable ion beam baffle. The ion source generates a positively charged ion beam. The neutralizer generates a negatively charged electron beam. The electron beam generated by the neutralizer neutralizes the positively charged ion beam generated by the ion source to prevent the accumulation of positive charges in the ion beam on the surface of the hemispherical harmonic oscillator. The ion beam baffle includes a closed state and an open state. The closed state blocks the ion beam from reaching the hemispherical harmonic oscillator, and the open state allows the ion beam to reach the hemispherical harmonic oscillator. Wherein, the ion beam baffle is initially in a closed state and the ion source and the neutralizer are activated, the step of controlling the ion beam etching module to etch the hemispherical harmonic oscillator using an ion beam according to the plurality of etching positions and the etching duration corresponding to each etching position includes: For the nth etching position among the plurality of etching positions, the hemispherical harmonic oscillator is controlled to move and / or rotate to a predetermined position corresponding to the nth etching position, so that the ion beam generated by the ion beam etching module can be focused at the nth etching position, 1≤n≤N, where N is the total number of the plurality of etching positions; When the hemispherical harmonic oscillator has been moved and / or rotated to the predetermined position corresponding to the nth etching position, the ion beam baffle is controlled to move from the closed state to the open state so that the ion beam can start etching the nth etching position; If the ion beam has been continuously etching the etching time corresponding to the nth etching position, the ion beam baffle is controlled to move from the open state to the closed state to stop the etching of the nth etching position.

2. The system according to claim 1, characterized in that, The step of determining multiple etching positions for etching the hemispherical resonator and the etching duration corresponding to each etching position based on the orientation of the principal axis of vibration and the magnitude of frequency fragmentation includes: Based on the orientation of the principal axis of vibration of the hemispherical harmonic oscillator, determine multiple etching positions for etching the surface of the hemispherical harmonic oscillator. The total etching time is determined based on the magnitude of the frequency split of the hemispherical harmonic oscillator and the preset ion beam etching rate corresponding to the ion beam etching module. The etching time corresponding to each etching location is determined based on the number of etching locations and the total etching time.

3. The system according to claim 1, characterized in that, The control module is also used for: The excitation module is controlled to apply an excitation signal with the same natural frequency as the hemispherical harmonic oscillator to the hemispherical harmonic oscillator to excite the hemispherical harmonic oscillator to vibrate; When the vibration amplitude of the hemispherical harmonic oscillator is stable, the excitation module is controlled to disconnect the excitation signal so that the vibration of the hemispherical harmonic oscillator can decay freely. The laser interferometer is controlled to collect vibration information at at least two positions of the hemispherical harmonic oscillator during the vibration decay process.

4. The system according to claim 1 or 3, characterized in that, The excitation module includes at least one set of interdigital electrodes and a high-voltage amplifier connected to each of the at least one set of interdigital electrodes; The input terminal of the high-voltage amplifier is connected to the control module and is used to amplify at least one excitation signal output by the control module and transmit the amplified at least one excitation signal to the at least one set of interdigital electrodes, so as to apply the amplified at least one excitation signal to the hemispherical harmonic oscillator through the at least one set of interdigital electrodes, thereby exciting the hemispherical harmonic oscillator to vibrate, wherein one excitation signal corresponds to one set of interdigital electrodes.

5. The system according to claim 1, characterized in that, The system also includes: a vacuum chamber, a displacement stage, a rotary table, a resonator fixture, and a fixed fixture; wherein, the vacuum chamber is used to provide a vacuum environment for the system; The displacement stage is used to control the horizontal and vertical movement of the hemispherical resonator to adjust the horizontal position and vertical etching position of the hemispherical resonator relative to the ion source in the ion beam etching module. The rotary table is fixedly connected above the displacement stage and is used to control the rotation of the hemispherical harmonic oscillator around the axis of symmetry, so as to achieve etching of different etching positions of the hemispherical harmonic oscillator in the circumferential direction. The resonator clamp is coaxially fixed to the rotary table and passes through the fixing fixture, and is used to fix the hemispherical resonator above the fixing fixture; The fixing fixture is coaxially fixed to the displacement stage and is used to fix at least one set of interdigitated electrodes in the excitation module and at least two detection probes of the laser interferometer; wherein, the at least two detection probes are circumferentially distributed on the fixing fixture and the angle between the line connecting two adjacent detection probes and the hemispherical resonator support column is 45°.

6. A method for mass leveling a hemispherical harmonic oscillator, characterized in that, The method is implemented based on the mass leveling system according to any one of claims 1 to 5, and the method includes: The hemispherical harmonic oscillator is excited to vibrate using an excitation signal that has the same natural frequency as the hemispherical harmonic oscillator to be leveled. Once the vibration amplitude of the hemispherical harmonic oscillator is stable, the excitation signal is disconnected to allow the vibration of the hemispherical harmonic oscillator to decay freely. The vibration information of the hemispherical harmonic oscillator at at least two positions during the vibration decay process is collected, wherein the vibration information at at least two positions includes at least two vibration displacements of the lip of the hemispherical harmonic oscillator at a circumferential distance of 45°. Based on the vibration information collected from at least two locations, the orientation of the principal axis of vibration of the hemispherical harmonic oscillator and the magnitude of the frequency split are determined. Based on the orientation of the principal axis of vibration of the hemispherical harmonic oscillator and the magnitude of the frequency split, multiple etching positions for etching the hemispherical harmonic oscillator and the etching duration corresponding to each etching position are determined. Based on the multiple etching locations and the etching duration corresponding to each etching location, an ion beam is used to etch the hemispherical harmonic oscillator in order to achieve mass leveling of the hemispherical harmonic oscillator.

7. The method according to claim 6, wherein determining multiple etching positions for etching the hemispherical resonator and the etching duration corresponding to each etching position based on the orientation of the principal axis of vibration and the magnitude of frequency fragmentation of the hemispherical resonator comprises: Based on the orientation of the principal axis of vibration of the hemispherical harmonic oscillator, determine multiple etching positions for etching the surface of the hemispherical harmonic oscillator. The total etching time is determined based on the magnitude of the frequency split of the hemispherical harmonic oscillator and the preset ion beam etching rate corresponding to the ion beam etching module. The etching time corresponding to each etching location is determined based on the total number of etching locations and the total etching time.

8. The method according to claim 6, characterized in that, The etching of the hemispherical harmonic oscillator using an ion beam based on the plurality of etching positions and the etching duration corresponding to each etching position includes: For the nth etching position among the plurality of etching positions, the hemispherical harmonic oscillator is controlled to move and / or rotate to a predetermined position corresponding to the nth etching position, so that the ion beam can be focused at the nth etching position, 1≤n≤N, where N is the total number of the plurality of etching positions; When the hemispherical harmonic oscillator has been moved and / or rotated to the predetermined position corresponding to the nth etching position, the nth etching position is etched using an ion beam for the etching duration corresponding to the nth etching position.

9. The method according to any one of claims 6 to 8, characterized in that, After etching the hemispherical harmonic oscillator using an ion beam according to the plurality of etching locations and the etching duration corresponding to each etching location, the method further includes: The orientation of the principal axis of vibration of the hemispherical harmonic oscillator and the magnitude of the frequency split are re-determined, and it is determined whether the re-determined magnitude of the frequency split meets the preset index. If the magnitude of the redefined frequency split does not meet the preset target, the hemispherical harmonic oscillator is etched again using an ion beam based on the redefined orientation of the main vibration axis and the magnitude of the frequency split.

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