A method for magnetorheological finishing-ion beam fractional frequency splitting trimming of a ground and pickled hemispherical resonator

Abstract

The application discloses a kind of grinding pickling after hemispherical resonator magnetorheological polishing-ion beam grading frequency cracking tuning method, it is related to hemispherical resonator precision manufacturing technical field, to solve the problem of low efficiency, long cycle of existing pure magnetorheological polishing or ion beam tuning method.For technical points of the present application include: S1, the hemispherical resonator after grinding is pickled;S2, obtain the high-frequency axis direction of hemispherical resonator, low-frequency axis direction and frequency cracking value;S3, if the frequency cracking value measured is greater than the first preset threshold value, then determine the local pre-tuning position according to the high-frequency axis direction, low-frequency axis direction, and the hemispherical resonator is locally pre-tuned using magnetorheological polishing;S4, repeat steps S2-S3 until the frequency cracking value measured is less than or equal to the first preset threshold value;S5, determine the precision tuning position based on the high-frequency axis direction, low-frequency axis direction, and the hemispherical resonator is tuned using ion beam.

Description

Technical Field

[0001] This invention relates to the field of precision manufacturing technology of hemispherical resonators, specifically to a magnetorheological polishing-ion beam graded frequency splitting and adjustment method for hemispherical resonators after grinding and acid washing. Background Technology

[0002] The hemispherical resonator is the core sensitive element in a high-precision hemispherical resonator gyroscope. Its circumferential mass distribution, circumferential stiffness distribution, surface quality, and structural symmetry have a significant impact on frequency splitting, quality factor, and operational stability.

[0003] The fabrication of hemispherical resonators typically involves grinding, pickling, and adjustment. After grinding, the surface of the hemispherical resonator usually exhibits subsurface damage of a certain depth, such as microcracks, chipping pits, brittle fracture zones, and localized plastic striations. To remove the subsurface damage introduced by grinding, pickling with an etchant containing hydrofluoric acid is commonly used.

[0004] However, for hemispherical resonators that are directly acid-washed after grinding, the reaction rates between surface cracks, chipping pits, and different damaged areas and the etching solution are significantly different. This leads to uneven etching during the acid-washing process, which deteriorates the surface roughness and produces morphological features such as pits, canyons, and boundary lines in local areas. These surface roughening and localized uneven removal further cause an imbalance in the circumferential mass and stiffness distribution of the hemispherical resonator, resulting in significant initial frequency fragmentation.

[0005] Currently, frequency fragmentation correction of hemispherical resonators typically employs ion beam correction. Ion beam correction offers advantages such as non-contact operation, high removal precision, and the ability to achieve minute-level precision removal, making it suitable for fine correction under low-frequency fragmentation conditions. However, when the initial frequency fragmentation of the acid-washed hemispherical resonator is significant, relying solely on gradual ion beam correction often results in a long correction cycle due to the low material removal efficiency of the ion beam, leading to low correction efficiency.

[0006] Magnetorheological polishing (MRP) is an ultra-precision machining method characterized by high removal efficiency, low processing damage, and excellent controllability. A ball-head permanent magnet MRP head can create a flexible polishing zone at the working end and achieve stable removal of complex curved surfaces through a controllable polishing gap. Therefore, if MRP is introduced into the frequency splitting and tuning process of a hemispherical harmonic oscillator, first using MRP to quickly remove the roughened surface layer from acid pickling and reduce significant initial frequency splitting, and then using an ion beam for high-precision finishing, it is hoped that both tuning efficiency and tuning accuracy can be achieved.

[0007] Therefore, there is an urgent need to propose a graded adjustment method for hemispherical harmonic oscillators after grinding and pickling, in order to solve the problem of long adjustment cycles when using ion beams alone in the existing technology. Summary of the Invention

[0008] The technical problem to be solved by this invention is:

[0009] To address the problems of low efficiency and long cycle time in existing simple magnetorheological polishing or ion beam trimming methods.

[0010] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0011] To solve the above-mentioned technical problems, the present invention provides a magnetorheological polishing-ion beam graded frequency splitting and tuning method for a hemispherical resonator after grinding and acid pickling, comprising the following steps:

[0012] S1. Grind the hemispherical harmonic oscillator and then pickle the ground hemispherical harmonic oscillator to remove the subsurface damage layer formed by grinding.

[0013] S2. Vibration detection is performed on the pickled hemispherical harmonic oscillator to obtain the natural frequencies of the high-frequency working mode, the natural frequencies of the low-frequency working mode, the high-frequency axis orientation, and the low-frequency axis orientation of the hemispherical harmonic oscillator. The frequency splitting value is calculated through the natural frequencies of the high-frequency working mode and the natural frequencies of the low-frequency working mode.

[0014] S3. If the measured frequency splitting value is greater than the first preset threshold, the local pre-adjustment position is determined according to the high frequency axis orientation, the low frequency axis orientation and the preset adjustment latitude angle range, and magnetorheological polishing is used to perform local pre-adjustment on the outer spherical surface and / or inner spherical surface of the hemispherical harmonic oscillator.

[0015] S4. Repeat steps S2-S3 until the measured frequency splitting value is less than or equal to the first preset threshold, then enter the ion beam precision adjustment stage.

[0016] S5. Based on the high-frequency axis orientation, low-frequency axis orientation, and preset adjustment latitude angle range, determine the precision adjustment position, and use an ion beam to perform graded precision adjustment on the outer and / or inner spherical surfaces of the hemispherical harmonic oscillator until the frequency splitting value is less than or equal to the third preset threshold, thus completing the adjustment of the hemispherical harmonic oscillator.

[0017] Furthermore, in step S1, the hemispherical harmonic oscillator after grinding is subjected to acid pickling treatment, and the etching solution used is an etching solution containing hydrofluoric acid.

[0018] Furthermore, before pre-adjusting the outer and / or inner spherical surfaces of the hemispherical resonator in step S3, the hemispherical resonator is subjected to global homogenization polishing using magnetorheological polishing to remove the acid-washed roughened surface layer and improve the surface roughness.

[0019] Furthermore, the amount of material removed in a single pass by magnetorheological polishing is determined by the magnetorheological polishing removal rate and the residence time, and the local removal depth of magnetorheological polishing is: Δh MRF =vMRF* t d , where Δh MRF For local removal depth, v MRF For magnetorheological polishing removal rate, t d For length of stay.

[0020] Furthermore, in step S3, the preset adjustment latitude angle θ is set at 0° at the edge of the hemispherical harmonic oscillator opening, and gradually increases towards the transition fillet area of ​​the support rod along the generatrix of the hemispherical shell. The local pre-adjustment position includes one or more of the following positions:

[0021] (1) The low-frequency axial orientation of the first adjustment region of the outer spherical surface, wherein the first adjustment region of the outer spherical surface satisfies 0°≤θ≤18°;

[0022] (2) The high-frequency axis orientation of the second adjustment area of ​​the outer spherical surface, wherein the second adjustment area of ​​the outer spherical surface satisfies θ≥55° and is located in the area of ​​the outer spherical surface near the transition fillet of the support rod;

[0023] (3) The low-frequency axis orientation of the third adjustment zone of the inner sphere, wherein the third adjustment zone of the inner sphere satisfies 10°≤θ≤58°.

[0024] Furthermore, the graded precision adjustment positions mentioned in step S5 include one or more of the following positions:

[0025] (1) The low-frequency axial orientation of the first adjustment region of the outer spherical surface, wherein the first adjustment region of the outer spherical surface satisfies 0°≤θ≤18°;

[0026] (2) The high-frequency axis orientation of the second adjustment area of ​​the outer spherical surface, wherein the second adjustment area of ​​the outer spherical surface satisfies θ≥55° and is located in the area of ​​the outer spherical surface near the transition fillet of the support rod;

[0027] (3) The low-frequency axis orientation of the third adjustment zone of the inner sphere, wherein the third adjustment zone of the inner sphere satisfies 10°≤θ≤58°.

[0028] Further, in step S5, the outer spherical surface of the hemispherical resonator is precisely tuned using an ion beam in stages. Specifically: if the frequency splitting value Δf satisfies Δf2<Δf≤Δf1, then local removal of the ion beam is performed in the high-frequency axis orientation of the second tuning region of the outer spherical surface to achieve stiffness-dominant tuning; if the frequency splitting value Δf satisfies Δf3<Δf≤Δf2, then local removal of the ion beam is performed in the low-frequency axis orientation of the first tuning region of the outer spherical surface and / or the low-frequency axis orientation of the third tuning region of the inner spherical surface to achieve mass-stiffness coupling precision tuning; if the frequency splitting value Δf≤Δf3, then the frequency splitting tuning of the hemispherical resonator is completed; where Δf1 is the first preset threshold, which is the switching threshold between magnetorheological polishing pre-tuning and ion beam precision tuning; Δf2 is the second preset threshold, which is the switching threshold between ion beam stiffness-dominant tuning and mass-stiffness coupling precision tuning; Δf3 is the first preset threshold, which is the switching threshold between ion beam stiffness-dominant tuning and mass-stiffness coupling precision tuning; and Δf3 is the second preset threshold, which is the first ... first preset threshold, which is the second preset threshold, which is the first preset threshold, which is the first preset threshold, which is the second preset threshold, which is the first preset threshold, which is the second preset threshold, which is the first preset threshold, which is the second preset threshold, which is the first preset threshold, which is the second preset threshold, which is the second preset threshold, which is the first preset threshold, which is the second preset threshold, which is the second preset threshold, which is The third preset threshold is the final target threshold, and Δf1 > Δf2 > Δf3 is satisfied.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] (1) By introducing magnetorheological polishing before ion beam finishing, the present invention can take advantage of the high efficiency and low damage of magnetorheological polishing to quickly remove the acid-washed roughened surface and significantly reduce the large initial frequency pyrolysis.

[0031] (2) By reducing the frequency splitting to below the first preset threshold and then switching to ion beam precision adjustment, the high precision advantage of the ion beam can be fully utilized to achieve precision adjustment of the final small frequency splitting. By adopting the graded adjustment method of "magnetorheological rapid pre-adjustment + ion beam precision adjustment", the overall adjustment cycle is significantly shortened.

[0032] (3) The present invention can achieve partitioned adjustment of the outer spherical surface and / or the inner spherical surface of the hemispherical harmonic oscillator. According to the range of frequency splitting value, stiffness-dominated adjustment can be performed at the high-frequency axis position of the outer spherical surface θ≥55°, or mass-stiffness coupled precision adjustment can be performed at the low-frequency axis position of the outer spherical surface 0°≤θ≤18° and / or the inner spherical surface 10°≤θ≤58°, thereby taking into account the adjustment efficiency, adjustment accuracy and controllability of the adjustment mechanism.

[0033] The method of this invention fully combines the advantages of high efficiency and low damage of magnetorheological polishing with the high precision of ion beam, and has good engineering application value. Attached Figure Description

[0034] Figure 1 This is a flowchart of the magnetorheological polishing-ion beam graded frequency splitting and adjustment method for a hemispherical harmonic oscillator after grinding and acid washing in an embodiment of the present invention.

[0035] Figure 2This is a schematic diagram of the roughening evolution of the grinding surface after pickling in an embodiment of the present invention;

[0036] Figure 3 This is a schematic diagram of the structure of the ultra-precision magnetorheological polishing rapid pre-adjustment device in an embodiment of the present invention;

[0037] Figure 4 This is a schematic diagram of the shared local adjustment position for magnetorheological polishing pre-adjustment and ion beam precision adjustment in an embodiment of the present invention.

[0038] Figure 5 This is a schematic diagram illustrating the relationship between the frequency splitting value and the preset threshold during the magnetorheological polishing-ion beam graded adjustment process in an embodiment of the present invention.

[0039] Figure 6 This is a schematic diagram showing the flexible polishing area and polishing gap formed at the ball end of the ball-head permanent magnet magnetorheological polishing head in an embodiment of the present invention.

[0040] Figure 7 This is a schematic diagram of the actual object used for magnetorheological polishing pre-adjustment in an embodiment of the present invention.

[0041] Explanation of reference numerals in the attached figures:

[0042] 1—Z-axis motion platform, 2—C-axis rotary platform, 3—U-axis micro-displacement platform, 4—magnetorheological fluid recovery peristaltic pump, 5—magnetorheological fluid storage tank, 6—worktable, 7—tool spindle, 8—small diameter ball head permanent magnet polishing head, 9—hemispherical resonator, 10—workpiece spindle, 11—magnetorheological fluid nozzle, 12—magnetorheological fluid recovery tank, 13—magnetorheological fluid supply peristaltic pump, 14—XY-axis motion platform. Detailed Implementation

[0043] To enable those skilled in the art to better understand the present invention, exemplary embodiments or examples of the present invention will be described below in conjunction with the accompanying drawings. Obviously, the described embodiments or examples are merely some, not all, of the embodiments or examples of the present invention. All other embodiments or examples obtained by those skilled in the art based on the embodiments or examples of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0044] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0045] The present invention will be further described below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited thereto.

[0046] This invention effectively solves the problem of large-frequency fragmentation of hemispherical harmonic oscillators after grinding and acid washing by adopting a graded process flow of "grinding and pickling - vibration detection and adjustment position determination - magnetorheological polishing rapid pre-adjustment - retesting - ion beam graded precision adjustment".

[0047] Specific Implementation Plan 1: (e.g.) Figure 1 As shown, this embodiment provides a magnetorheological polishing-ion beam graded frequency splitting adjustment method for a hemispherical resonator after grinding and acid pickling, which specifically includes the following steps:

[0048] S1. First, the fused silica hemispherical resonator is ground to form the target shape and basic dimensions. Then, the ground hemispherical resonator is acid-washed to remove the subsurface damage layer formed by the grinding process.

[0049] S2. Vibration excitation and vibration response detection are performed on the acid-washed hemispherical resonator to obtain the natural frequency f of the high-frequency operating mode of the hemispherical resonator. H Low-frequency operating mode natural frequency f L High-frequency axial orientation φ H Low-frequency axial orientation φ L And calculate the frequency splitting value Δf=|f H -f L |

[0050] S3. If the measured frequency splitting value is greater than the first preset threshold, then according to the high-frequency axis orientation φ H Low-frequency axial orientation φ L In addition, a preset latitude angle range is used to determine the local adjustment position of the hemispherical harmonic oscillator; magnetorheological polishing is used to perform local pre-adjustment on the outer and / or inner spherical surfaces of the hemispherical harmonic oscillator.

[0051] S4. Repeat steps S2-S3 until the measured frequency splitting value is less than or equal to the first preset threshold, then enter the ion beam precision adjustment stage.

[0052] S5. Based on the high-frequency axis orientation, low-frequency axis orientation, and preset adjustment latitude angle range, determine the precision adjustment position, and use an ion beam to perform graded precision adjustment on the outer and / or inner spherical surfaces of the hemispherical harmonic oscillator until the frequency splitting value is less than or equal to the second preset threshold, thus completing the adjustment of the hemispherical harmonic oscillator.

[0053] It should be noted that the latitude angle θ is adjusted with the edge of the hemispherical harmonic oscillator opening at θ=0°, gradually increasing towards the transition radius region of the support rod along the generatrix of the hemispherical shell. The applicant established a finite element model of local material removal from the hemispherical harmonic oscillator, equating local material removal with the corresponding mass loss and stiffness reduction. Combined with fixed-point ion beam removal experiments, the influence of material removal at different latitude angles and axial orientations on frequency fragmentation was determined. The results show that when local material removal is located in the outer spherical region where θ≥55°, its influence on frequency fragmentation is mainly dominated by stiffness; when local material removal is located in the outer spherical region where 0°≤θ≤18° and the inner spherical region where 10°≤θ≤58°, its influence on frequency fragmentation is a mass-stiffness coupling effect. Furthermore, the influence of removing the same material in the stiffness region on frequency fragmentation is greater than that in the mass-stiffness coupling region. Therefore, in this embodiment, the low-frequency axis position of the outer spherical surface 0°≤θ≤18°, the high-frequency axis position of the outer spherical surface θ≥55°, and the low-frequency axis position of the inner spherical surface 10°≤θ≤58° are selected as preferred local adjustment positions.

[0054] Specific Implementation Scheme Two: In step S1, the ground hemispherical harmonic oscillator is acid-washed with a hydrofluoric acid-containing etchant to remove the subsurface damage layer introduced by grinding. During the acid washing process, due to the different reaction rates between grinding cracks, chipping pits, and different damaged areas and the hydrofluoric acid-containing etchant, roughened areas and locally non-uniform removal areas will form on the surface of the hemispherical harmonic oscillator. Other aspects of this implementation scheme are the same as in Specific Implementation Scheme One.

[0055] like Figure 2 As shown, plastic striations and brittle features are visible on the surface before acid etching. With increasing chemical etching time, micro-defects, canyon-like defects, pits, and boundary lines gradually appear, eventually manifesting as surface roughening. This type of surface roughening not only deteriorates the surface quality but also causes uneven circumferential removal, resulting in an imbalance in circumferential mass and stiffness distribution, leading to higher frequency fractures.

[0056] Specific Implementation Scheme 3: In step S3, when the detected frequency fragmentation value is greater than the first preset threshold Δf1, it indicates that the acid-washed hemispherical resonator has a large initial frequency fragmentation. At this time, magnetorheological polishing is used for rapid pre-adjustment. First, magnetorheological polishing is used to perform global homogenization polishing on the hemispherical resonator to remove the roughened surface layer from the acid washing and improve the surface roughness. Then, the outer and / or inner spherical surfaces of the hemispherical resonator are pre-adjusted to perform local material removal in specific orientation and latitude regions to quickly reduce frequency fragmentation. The rest of this implementation scheme is the same as Specific Implementation Scheme 1.

[0057] The magnetorheological polishing employs a ball-head permanent magnet magnetorheological polishing head. This head forms a flexible polishing zone at its working end and maintains a preset polishing gap with the surface of the hemispherical harmonic oscillator. The magnetorheological polishing head is controlled and adjusted for latitude and azimuth via a multi-axis motion platform. The magnetorheological polishing head is used in conjunction with a magnetorheological fluid circulation device, which includes a magnetorheological fluid storage tank, a magnetorheological fluid supply peristaltic pump, a magnetorheological fluid nozzle, a magnetorheological fluid recovery tank, and a magnetorheological fluid recovery peristaltic pump, used to achieve the supply, recovery, and circulation of the magnetorheological fluid.

[0058] Specific Implementation Scheme Four: The single-pass removal amount of the magnetorheological polishing rapid pre-adjustment is determined by the magnetorheological polishing removal rate and residence time, and the removal depth of the magnetorheological polishing is: Δh MRF =v MRF* t d , where Δh MRF To remove depth, v MRF For magnetorheological polishing removal rate, t d This refers to the length of stay. All other aspects of this implementation plan are the same as those in Specific Implementation Plan One.

[0059] Specific Implementation Scheme 5: Local frequency fragmentation pre-adjustment can be selected at different adjustment positions based on the magnitude of the frequency fragmentation value, the axial orientation, and the preset adjustment latitude angle range. As shown in Figure 4, the local adjustment position in this embodiment is a shared adjustment position for both magnetorheological polishing pre-adjustment and ion beam precision adjustment. The local pre-adjustment position includes one or more of the following positions:

[0060] (1) Local pre-adjustment is performed in the low-frequency axis orientation of the first adjustment zone of the outer spherical surface, wherein the first adjustment zone of the outer spherical surface satisfies 0°≤θ≤18°;

[0061] (2) Local pre-adjustment is performed in the high-frequency axis orientation of the second adjustment area of ​​the outer spherical surface, wherein the second adjustment area of ​​the outer spherical surface satisfies θ≥55° and is located in the area of ​​the outer spherical surface near the transition fillet of the support rod;

[0062] (3) Local pre-adjustment is performed in the low-frequency axis orientation of the third adjustment zone of the inner sphere, wherein the third adjustment zone of the inner sphere satisfies 10°≤θ≤58°.

[0063] Let the low-frequency axis orientation be φ L The high-frequency axis orientation is φ H The corresponding positions for the four low-frequency axes and the four high-frequency axes are as follows:

[0064] φ L,i =φ L +iπ / 2, i=0,1,2,3

[0065] φ H,i =φ H+iπ / 2, i=0,1,2,3

[0066] Where, φ L,i For the i-th low-frequency axis adjustment orientation, φ H,i Let φ be the adjustment orientation for the i-th high-frequency axis. During actual adjustment, the local adjustment position is determined by the adjustment orientation φ. L,i or φ H,i It is determined together with the adjusted latitude angle θ. All other aspects of this implementation plan are the same as in Specific Implementation Plan One.

[0067] Specific implementation plan six: The graded precision adjustment positions mentioned in step S5 include one or more of the following positions:

[0068] (1) The low-frequency axis position φ in the first adjustment region of the outer spherical surface L,i The ion beam is precisely adjusted locally, with the first adjustment region on the outer spherical surface satisfying 0°≤θ≤18°.

[0069] (2) The high-frequency axis position φ in the second adjustment zone of the outer spherical surface H,i The ion beam is precisely adjusted locally, and the second adjustment area on the outer spherical surface satisfies θ≥55° and is located in the area of ​​the outer spherical surface near the transition radius of the support rod.

[0070] (3) The low-frequency axis position φ in the third adjustment zone of the inner spherical surface L,i The ion beam is precisely adjusted locally, with the third adjustment region on the inner sphere satisfying 10°≤θ≤58°. All other aspects of this implementation scheme are the same as in specific implementation scheme five.

[0071] For the high-latitude, high-frequency axis region, material removal primarily serves to adjust stiffness. For the mid-to-low-latitude, low-frequency axis region, material removal simultaneously alters local mass and local stiffness, exhibiting a mass-stiffness coupled adjustment effect. Therefore, magnetorheological polishing is used for local precision adjustment on the outer spherical surface of the hemispherical resonator, employing a hierarchical adjustment logic of "high-latitude, high-frequency axis stiffness adjustment + low-latitude, low-frequency axis mass-stiffness coupled adjustment." Specifically: if the frequency splitting value is greater than the third preset threshold Δf3 and less than the second threshold Δf2, local precision adjustment is performed at the high-latitude, high-frequency axis position on the outer spherical surface of the hemispherical resonator to achieve stiffness adjustment; conversely, if the frequency splitting value is less than or equal to the third preset threshold Δf3, local precision adjustment is performed at the low-latitude, low-frequency axis position on the outer spherical surface of the hemispherical resonator to achieve mass-stiffness coupled adjustment.

[0072] Specific implementation plan seven: In step S5, the outer spherical surface of the hemispherical resonator is precisely tuned using an ion beam in stages. Specifically, when the frequency splitting value Δf satisfies Δf2<Δf≤Δf1, ion beam local removal is first performed at the high-frequency axis position of the second tuning region on the outer spherical surface of the hemispherical resonator to achieve stiffness-dominated tuning; when the frequency splitting value Δf decreases to Δf3<Δf≤Δf2, ion beam local removal is then performed at the low-frequency axis position of the first tuning region on the outer spherical surface of the hemispherical resonator and / or the low-frequency axis position of the third tuning region on the inner spherical surface to achieve mass-stiffness coupling precision tuning; when the frequency splitting value Δf≤Δf3, the frequency splitting tuning of the hemispherical resonator is completed. The first preset threshold Δf1 is the switching threshold between rapid pre-adjustment of magnetorheological polishing and precise adjustment of ion beam; the second preset threshold Δf2 is the switching threshold between ion beam stiffness-dominated adjustment and mass-stiffness coupled precise adjustment; and the third preset threshold Δf3 is the final target threshold, satisfying: Δf1 > Δf2 > Δf3. Other aspects of this implementation scheme are the same as in specific implementation scheme six.

[0073] In a preferred embodiment, a first preset threshold Δf1 can be determined based on the initial frequency fragmentation size and the stability of magnetorheological polishing removal. For example, Δf1 can be approximately 0.01 Hz; a second preset threshold Δf2 can be approximately 0.001 Hz; and a third preset threshold Δf3 can be approximately 0.0001 Hz. The above values ​​are merely preferred examples and do not constitute a limitation on the scope of protection of this invention.

[0074] As shown in Figure 5, in this embodiment, the initial frequency fragmentation of the acid-washed hemispherical harmonic oscillator is approximately 0.11 Hz. Through multiple rapid pre-adjustments using magnetorheological polishing, the frequency fragmentation value gradually decreases, and around the 7th adjustment, it drops to near the first preset threshold Δf1. After that, it switches to ion beam precision adjustment.

[0075] This example demonstrates that, compared to relying entirely on stepwise removal via ion beam, the present invention, through rapid pre-adjustment via magnetorheological polishing, can significantly reduce the initial frequency fragmentation value when entering the ion beam adjustment stage, thereby reducing the amount of removal and the number of adjustments required for subsequent ion beam adjustment.

[0076] like Figure 3 As shown, the magnetorheological polishing rapid pre-adjustment device of this embodiment includes: a Z-axis motion platform 1, a C-axis rotary platform 2, a U-axis micro-displacement platform 3, a magnetorheological fluid recovery peristaltic pump 4, a magnetorheological fluid storage tank 5, a worktable 6, a tool spindle 7, a small-diameter ball-head permanent magnet polishing head 8, a hemispherical resonator 9, a workpiece spindle 10, a magnetorheological fluid nozzle 11, a magnetorheological fluid recovery tank 12, a magnetorheological fluid supply peristaltic pump 13, and an XY-axis motion platform 14.

[0077] The hemispherical resonator 9 is mounted on the workpiece spindle 10, which is located on the worktable 6. The small-diameter ball-head permanent magnet polishing head 8 is mounted on the tool spindle 7, which is located on the Z-axis motion platform 1.

[0078] The XY-axis motion platform 14 is used to control the position adjustment of the workpiece in the horizontal plane; the Z-axis motion platform 1 is used to control the vertical position adjustment of the tool spindle 7 and the small-diameter ball-head permanent magnet polishing head 8; the C-axis rotation platform 2 is used to adjust the posture of the polishing head and adjust the azimuth angle; the U-axis micro-displacement platform 3 is used to precisely adjust the center of the ball of the small-diameter ball-head permanent magnet polishing head 8 to coincide with the rotation axis of the C-axis rotation platform 2, so as to ensure geometric consistency during the posture adjustment process of the polishing head.

[0079] The magnetorheological fluid nozzle 11 is connected to the magnetorheological fluid supply peristaltic pump 13 and the magnetorheological fluid storage tank 5, and is used to provide fresh magnetorheological fluid to the vicinity of the small-diameter ball-head permanent magnet polishing head 8; the magnetorheological fluid recovery tank 12 is connected to the magnetorheological fluid recovery peristaltic pump 4, and is used to recover the used magnetorheological fluid and send it back to the storage tank 5, thereby forming a magnetorheological fluid circulation loop.

[0080] The multi-axis motion platform works in conjunction with the workpiece spindle 10 and the tool spindle 7, enabling the small-diameter ball-head permanent magnet polishing head 8 to achieve rapid pre-adjustment at different latitudes and azimuth angles on the outer and / or inner spherical surfaces of the hemispherical harmonic oscillator 9.

[0081] like Figure 6 As shown, the ball-head permanent magnet magnetorheological polishing head has a permanent magnet at its working end. Under the action of the permanent magnetic field, the ferromagnetic particles of the magnetorheological fluid align along the magnetic field lines, causing the magnetorheological fluid to form a flexible polishing zone with a certain yield stress at the ball end.

[0082] The flexible polishing zone is located between the ball-head permanent magnet magnetorheological polishing head and the surface of the hemispherical harmonic oscillator, maintaining a certain polishing gap. Fresh magnetorheological fluid is delivered to the polishing zone through the magnetorheological fluid nozzle 11. Under the action of the permanent magnetic field and relative motion, the abrasive particles in the magnetorheological fluid participate in material removal. The used magnetorheological fluid flows into the magnetorheological fluid recovery tank 12 and is recycled.

[0083] The aforementioned flexible polishing zone can reduce the risk of surface damage caused by rigid contact while ensuring high removal efficiency, making it suitable for rapid removal of roughened surfaces after acid pickling.

[0084] like Figure 7As shown, during the rapid pre-adjustment process of magnetorheological polishing, the small-diameter spherical permanent magnet polishing head approaches the surface of the hemispherical harmonic oscillator. Magnetorheological fluid is continuously replenished through the magnetorheological fluid nozzle 11, forming a magnetorheological fluid layer covering the polishing area on the surface of the hemispherical harmonic oscillator, and creating a stable local polishing area near the polishing head. This demonstrates that the spherical permanent magnet magnetorheological polishing head of the present invention can not only achieve adaptive contact with the complex curved surface of the hemispherical harmonic oscillator, but also achieve continuous, stable, and rapid pre-adjustment through the magnetorheological fluid circulation system.

[0085] While the present invention has been disclosed above, its scope of protection is not limited to the embodiments described above. Those skilled in the art can make various changes, substitutions, and modifications to the present invention without departing from its concept and scope of protection, and all such changes, substitutions, and modifications should fall within the scope of protection of the present invention.

Claims

1. A magnetorheological polishing-ion beam graded frequency splitting adjustment method for a hemispherical resonator after grinding and acid pickling, characterized in that: Includes the following steps: S1. Grind the hemispherical harmonic oscillator and then pickle the ground hemispherical harmonic oscillator to remove the subsurface damage layer formed by grinding. S2. Vibration detection is performed on the pickled hemispherical harmonic oscillator to obtain the natural frequencies of the high-frequency working mode, the natural frequencies of the low-frequency working mode, the high-frequency axis orientation, and the low-frequency axis orientation of the hemispherical harmonic oscillator. The frequency splitting value is calculated through the natural frequencies of the high-frequency working mode and the natural frequencies of the low-frequency working mode. S3. If the measured frequency splitting value is greater than the first preset threshold, the local pre-adjustment position is determined according to the high frequency axis orientation, the low frequency axis orientation and the preset adjustment latitude angle range, and magnetorheological polishing is used to perform local pre-adjustment on the outer spherical surface and / or inner spherical surface of the hemispherical harmonic oscillator. S4. Repeat steps S2-S3 until the measured frequency splitting value is less than or equal to the first preset threshold, then enter the ion beam precision adjustment stage. S5. Based on the high-frequency axis orientation, low-frequency axis orientation, and preset adjustment latitude angle range, determine the precision adjustment position, and use an ion beam to perform graded precision adjustment on the outer and / or inner spherical surfaces of the hemispherical harmonic oscillator until the frequency splitting value is less than or equal to the third preset threshold, thus completing the adjustment of the hemispherical harmonic oscillator.

2. The method according to claim 1, characterized in that: In step S1, the hemispherical harmonic oscillator after grinding is subjected to acid pickling, and the etching solution used is an etching solution containing hydrofluoric acid.

3. The method according to claim 1, characterized in that: Before pre-adjusting the outer and / or inner spherical surfaces of the hemispherical resonator in step S3, the hemispherical resonator is further subjected to global homogenization polishing using magnetorheological polishing to remove the acid-washed roughened surface layer and improve the surface roughness.

4. The method according to claim 1, characterized in that: The single removal amount of the magnetorheological finishing is determined by the magnetorheological finishing removal rate and the residence time, and the local removal depth of the magnetorheological finishing is: Δh MRF = v MRF* t d , wherein Δh MRF is the local removal depth, v MRF is the magnetorheological finishing removal rate, and t d is the residence time.

5. The method according to claim 1, characterized in that: In step S3, the preset adjustment latitude angle θ is set at the edge of the hemispherical harmonic oscillator opening as θ=0°, and gradually increases along the generatrix of the hemispherical shell towards the transition fillet area of ​​the support rod. The local pre-adjustment position includes one or more of the following positions: (1) The low-frequency axial orientation of the first adjustment region of the outer spherical surface, wherein the first adjustment region of the outer spherical surface satisfies 0°≤θ≤18°; (2) The high-frequency axis orientation of the second adjustment area of ​​the outer spherical surface, wherein the second adjustment area of ​​the outer spherical surface satisfies θ≥55° and is located in the area of ​​the outer spherical surface near the transition fillet of the support rod; (3) The low-frequency axis orientation of the third adjustment zone of the inner sphere, wherein the third adjustment zone of the inner sphere satisfies 10°≤θ≤58°.

6. The method according to claim 5, characterized in that: The graded precision adjustment positions mentioned in step S5 include one or more of the following positions: (1) The low-frequency axial orientation of the first adjustment region of the outer spherical surface, wherein the first adjustment region of the outer spherical surface satisfies 0°≤θ≤18°; (2) The high-frequency axis orientation of the second adjustment area of ​​the outer spherical surface, wherein the second adjustment area of ​​the outer spherical surface satisfies θ≥55° and is located in the area of ​​the outer spherical surface near the transition fillet of the support rod; (3) The low-frequency axis orientation of the third adjustment zone of the inner sphere, wherein the third adjustment zone of the inner sphere satisfies 10°≤θ≤58°.

7. The method according to claim 6, characterized in that: In step S5, an ion beam is used to perform graded precision tuning on the outer spherical surface of the hemispherical resonator. Specifically: if the frequency splitting value Δf satisfies Δf2<Δf≤Δf1, then ion beam local removal is performed in the high-frequency axis orientation of the second tuning region of the outer spherical surface to achieve stiffness-dominant tuning; if the frequency splitting value Δf satisfies Δf3<Δf≤Δf2, then ion beam local removal is performed in the low-frequency axis orientation of the first tuning region of the outer spherical surface and / or the low-frequency axis orientation of the third tuning region of the inner spherical surface to achieve mass-stiffness coupling precision tuning; if the frequency splitting value Δf≤Δf3, then the frequency splitting tuning of the hemispherical resonator is completed; where Δf1 is the first preset threshold, which is the switching threshold between magnetorheological polishing pre-tuning and ion beam precision tuning; Δf2 is the second preset threshold, which is the switching threshold between ion beam stiffness-dominant tuning and mass-stiffness coupling precision tuning; Δf3 is the first preset threshold, which is the switching threshold between ion beam stiffness-dominant tuning and mass-stiffness coupling precision tuning; and Δf3 is the second preset threshold, which is the first ... first preset threshold, which is the second preset threshold, which is the first preset threshold, which is the first preset threshold, which is the second preset threshold, which is the first preset threshold, which is the first preset threshold, which is the second preset threshold, which is the first preset threshold, which is the second preset threshold, which is the first preset threshold, which is the second preset threshold, which is the first preset threshold, which is the second preset threshold, which is the second preset threshold, which is the second preset threshold The third preset threshold is the final target threshold, and Δf1 > Δf2 > Δf3 is satisfied.

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