A liquid-floated gyroscopic float air tightness nondestructive testing method and testing tool

Abstract

The present application relates to a gyro detection method and detection tool, in particular to a liquid floated gyro bob airtightness nondestructive detection method and detection tool, which is used to solve the problem that there is no system and complete method suitable for liquid floated gyro bob airtightness nondestructive detection in the whole life cycle. The liquid floated gyro bob airtightness nondestructive detection method can guarantee the precision, stability and reliability of the liquid floated gyro by sequentially detecting the airtightness of the bob before inflation, after inflation, before assembly, before liquid floated gyro debugging delivery and during liquid floated gyro use. The present application has the advantages of easy implementation, simple operation and low difficulty.

Description

Technical Field

[0001] This invention relates to a gyroscope testing method and testing fixture, specifically to a non-destructive testing method and testing fixture for the airtightness of a liquid-float gyroscope float. Background Technology

[0002] Liquid-floating gyroscopes, due to their vibration resistance, shock resistance, high reliability, and long lifespan, are widely used in navigation and attitude control systems of spacecraft, satellites, space stations, missiles, and ships. As attitude-sensing elements, they are crucial inertial sensors used to measure the angular motion of the carrier. The long-term stability of liquid-floating gyroscopes affects the accuracy of navigation and attitude control systems. The manufacturing of liquid-floating gyroscopes involves complex precision machining and assembly techniques. Residual stress deformation caused by assembly and bonding stresses leads to a monotonically slow change in the gyroscope's center of mass over time, thus affecting its stability.

[0003] Figure 1 The diagram shows the coordinate system of a liquid-floating gyroscope. The OA axis, IA axis, and SA axis represent the output axis, input axis, and motor axis of the gyroscope, respectively. The liquid-floating gyroscope is in a vertically upward orientation along the OA axis, achieving full buoyancy at operating temperature, with no contact between the axis tip and the jewel bearing.

[0004] The float is a key component of a liquid-float gyroscope, and its airtightness directly affects the accuracy, stability, and reliability of the gyroscope. Figure 2 , Figure 3 This is a schematic diagram of the assembled float structure, including a frame 01, a float 02 fitted onto the outside of the frame 01, a terminal block 03 mounted on the frame 01, an air inlet 04, and a shaft tip 05 installed inside the frame 01. The sealing components of the float include: the connection between the frame 01 and the float 02, the connection between the terminal block 03 and the mounting hole of the frame 01, the connection between the air inlet 04 and the mounting hole of the frame 01, the welded seal of the air inlet 04, and the connection between the shaft tip 05 and the mounting hole of the frame 01.

[0005] The float houses a motor that provides the angular momentum of the liquid-floated gyroscope and is filled with a high-purity inert gas at a certain pressure, typically high-purity helium, to improve motor heat dissipation, reduce wind resistance losses in the high-speed rotor, and prevent oxidation of the lubricant in the motor, thereby extending its lifespan. The gap between the float and the shell is filled with a levitation fluid, allowing the float to remain fully suspended, thus reducing the normal pressure exerted by the float's own weight on the support. Simultaneously, the oil film formed between the jewel bearing and the support journal reduces the friction coefficient of the support system, thereby improving the instrument's threshold and resolution. Furthermore, it dampens the float's movement, giving the liquid-floated gyroscope excellent dynamic characteristics and enhancing its vibration and shock resistance.

[0006] Leaks in the float seal of a liquid-float gyroscope can cause instability in the center of gravity of the gyroscope assembled with a ball bearing motor, leading to decreased stability. Leaks in liquid-float gyroscopes assembled with an air bearing motor can contaminate the motor's operating environment, causing motor jamming and other unreliable issues. Therefore, to avoid accuracy deviations and motor jamming caused by float airtightness failure during operation, it is necessary to test the float's airtightness before and after inflation, before final assembly, during gyroscope debugging, before product delivery, and during use. This ensures reliable float sealing and guarantees the accuracy, stability, and reliability of the liquid-float gyroscope. Furthermore, airtightness testing must be non-destructive and must not contaminate the motor, otherwise, the reliability and lifespan of the liquid-float gyroscope will be affected. In the existing technology, although there are many non-destructive testing methods applicable to different stages of liquid-floated gyroscope floats, there is no continuity or systematicity among them, which makes it impossible to cover the entire life cycle of liquid-floated gyroscope floats. Moreover, these methods are all complex and cumbersome to operate and have long testing cycles. In other words, there is currently no report of a systematic and complete method applicable to non-destructive airtightness testing of liquid-floated gyroscope floats throughout their entire life cycle. Summary of the Invention

[0007] The purpose of this invention is to address the current lack of a system and complete method for non-destructive airtightness testing of liquid-floated gyroscope floats throughout their entire lifecycle, and to provide a non-destructive testing method and testing fixture for the airtightness of liquid-floated gyroscope floats.

[0008] To address the shortcomings of the existing technology, the present invention provides the following technical solution: A non-destructive testing method for the airtightness of a liquid-float gyroscope float, characterized by the following steps: Step 1: Before filling the float with gas, use the helium injection method to check for leaks in the float; and determine the leak rate of the float based on the amount of helium gas detected in the float. If the leak rate of the float meets the standard, proceed to Step 2; otherwise, it indicates that the airtightness of the float is abnormal, and the detection process ends. Step 2: After the float is inflated and before final assembly, perform a leak test on the float; The float is placed in a sealed cavity, the sealed cavity is evacuated by a mass spectrometer, and the leakage rate of the float is determined based on the detected amount of helium in the sealed cavity. If the float's leakage rate meets the standard, proceed to step 3; otherwise, it indicates that the float's airtightness is abnormal, and the testing process ends. Step 3: Debug the liquid-float gyroscope and check for leaks in the float before delivery; Step 3.1: After calibrating the sensitive axis of the liquid-floating gyroscope, make the positive direction of the SA axis of the liquid-floating gyroscope parallel to the direction of gravitational acceleration and upward, and the OA axis horizontally northward. After stabilizing for at least 10 minutes, rotate the liquid-floating gyroscope 90° around the OA axis so that the positive direction of the IA axis is parallel to the direction of gravitational acceleration and upward, and the OA axis horizontally northward. Immediately and continuously collect the gyroscope drift output for 120 min to 150 min, and plot the corresponding liquid-floating gyroscope output curve. Step 3.2: Determine whether the output curve of the liquid-floated gyroscope obtained in Step 3.1 meets the preset requirements; if it does, proceed to Step 3.3; otherwise, it indicates that the float is not airtight and the detection process ends. Step 3.3: Continue to continuously rotate the liquid-floating gyroscope after step 3.1 to collect the random drift of the fixed position of the liquid-floating gyroscope in multiple attitudes, and plot the corresponding output curve of the liquid-floating gyroscope; Step 3.4: Determine whether the output curves of the liquid-floated gyroscope obtained in Step 3.3 all meet the preset requirements; if they do, proceed to Step 4; otherwise, it indicates that the float's airtightness is abnormal, and the detection process ends. Step 4: Check the float for leaks during use of the liquid-float gyroscope; After the liquid-floating gyroscope is installed and calibrated, when the liquid-floating gyroscope is delivered to the inertial assembly for use, the gyroscope mounting plate is pressed against the positioning pin to realize the transformation between the coordinate system of the liquid-floating gyroscope and the coordinate system of the inertial assembly; combined with the test position and results of the inertial assembly, the airtightness of the float is judged by the methods in steps 3.3 and 3.4.

[0009] Further, in step 3.3, the multiple attitudes include the positive SA axis direction being parallel to the gravitational acceleration direction and downward, the positive IA axis direction being parallel to the gravitational acceleration direction and downward, the positive SA axis direction being parallel to the gravitational acceleration direction and upward, and the positive IA axis direction being parallel to the gravitational acceleration direction and upward.

[0010] Furthermore, step 3.3 specifically includes: Step 3.3.1: Rotate the liquid-floating gyroscope 90° around the OA axis so that the positive direction of SA is parallel to the direction of gravitational acceleration and downward, and the OA axis is horizontal and northward. Immediately and continuously collect the gyroscope drift output for 120 min to 150 min, and plot the corresponding liquid-floating gyroscope output curve. Step 3.3.2: Rotate the liquid-floating gyroscope 90° around the OA axis so that the positive direction of IA is parallel to the direction of gravitational acceleration and downward, and the OA axis is horizontal and northward. Immediately and continuously collect the gyroscope drift output for 120 min to 150 min, and plot the corresponding liquid-floating gyroscope output curve. Step 3.3.3: Rotate the liquid-floating gyroscope 90° around the OA axis so that the positive direction of SA is parallel to the direction of gravitational acceleration and upward, and the OA axis is horizontal and northward. Immediately and continuously collect the gyroscope drift output for 120 min to 150 min, and plot the corresponding liquid-floating gyroscope output curve. Step 3.3.4: Rotate the liquid-floating gyroscope 90° around the OA axis so that the positive direction of IA is parallel to the direction of gravitational acceleration and upward, and the OA axis is horizontal and northward. Immediately and continuously collect the gyroscope drift output for 120 min to 150 min, and plot the corresponding liquid-floating gyroscope output curve.

[0011] Further, in steps 3.1 and 3.3, the acquisition frequency is 1 data point per second; in steps 3.2 and 3.4, the preset requirements are: the gyroscope drift output change is significantly monotonically within the first 1 to 2 minutes, and the change in the zero point value of the gyroscope output is no greater than 0.0005 mA thereafter, and the standard deviation σ of the gyroscope drift output within the first 120 minutes is no greater than 0.05° / h.

[0012] Further, in step 1, the helium-spraying method for leak detection of the float before inflation specifically involves: placing the float on a V-shaped pad, and connecting the float inflation nozzle sequentially through a silicone tube, a glass tube, and a rubber tube to the detection terminal of a helium mass spectrometer; extracting air from the float's inner cavity using the helium mass spectrometer, and blowing air into the float's sealing area using a helium gun; if a leak occurs at the sealing area, helium enters the float's inner cavity, and the helium mass spectrometer detects helium ions, determining the float's leakage rate based on the amount of helium ions detected.

[0013] Meanwhile, the present invention provides a non-destructive testing fixture for the airtightness of a liquid-floating gyroscope float, used to form the sealing cavity described in step 2 of the above-mentioned non-destructive testing method for the airtightness of a liquid-floating gyroscope float. Its special feature is that it includes a shell, a quick-release clamp, and a leak detection cover. The outer wall of the housing is provided with a radial annular groove adapted to the quick-release clamp, and the housing is provided with an axial through hole; one side of the leak detection cover is hinged to the upper end of the housing to seal the upper end of the axial through hole, and the quick-release clamp is used to be set in the radial annular groove to fix the lower end of the axial through hole to the mass spectrometer to be connected, so that the axial through hole between the leak detection cover, the housing and the mass spectrometer forms the sealing cavity.

[0014] Furthermore, a hinge seat is provided on one side of the upper end of the housing, and a hinge member corresponding to the hinge seat is provided on one side of the leak detection cover. The leak detection cover is hinged to the upper end of the housing through the hinge member, the hinge seat, and the hinge shaft. A handle is provided on the outside of the leak detection cover on the side away from the hinge member.

[0015] Compared with the prior art, the beneficial effects of the present invention are: (1) The present invention provides a non-destructive testing method for the air tightness of a liquid-floating gyroscope float. By performing non-destructive testing on the air tightness of the float before inflation, after inflation, before final assembly, before commissioning and delivery of the liquid-floating gyroscope, and during use of the liquid-floating gyroscope, the accuracy, stability and reliability of the liquid-floating gyroscope can be guaranteed. Furthermore, the present invention has the advantages of being easy to implement, simple to operate and low in difficulty.

[0016] (2) The present invention provides a non-destructive testing method for the air tightness of a liquid-floating gyroscope float. Before the float is inflated, a helium spraying method is used for non-destructive testing, which does not pollute the motor. The test ensures that the sealing parts do not leak before inflation, thus confirming the reliability of the float's seal before inflation.

[0017] (3) The present invention provides a non-destructive testing method for the air tightness of a liquid-floating gyroscope float. The method uses helium pressure non-destructive testing after the float is inflated and before final assembly. It does not pollute the motor and verifies that the sealing parts do not leak after inflation, thus confirming the reliability of the float's seal after inflation.

[0018] (4) The present invention provides a non-destructive testing method for the airtightness of a liquid-floating gyroscope float. During the gyroscope debugging stage, before delivery, and during delivery and use, the drift output of the gyroscope is detected by attitude flipping to confirm that the float has no sealing quality problems.

[0019] (5) The present invention provides a non-destructive testing method for the air tightness of a liquid-floating gyroscope float. During the assembly stage, including before the float is filled with gas, after the float is filled with gas, and before the gyroscope is assembled, a helium mass spectrometer leak detection device is connected through a non-destructive testing fixture to quantitatively assess the air tightness of the float. During the debugging, delivery, and use of the liquid-floating gyroscope, the air tightness of the float is quantitatively assessed through the output of the gyroscope. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the coordinate system of a liquid-floated gyroscope. Figure 2 Schematic diagram of the structure of a liquid-float gyroscope float Figure 1 ; Figure 3 Schematic diagram of the structure of a liquid-float gyroscope float Figure 2 ; Figure 4 This is a schematic diagram of an embodiment of a non-destructive testing fixture for the air tightness of a liquid-floating gyroscope float according to the present invention (the leak detection cover and quick-release clamp are not shown). Figure 5 This is a schematic diagram of the leak detection cover in an embodiment of the present invention; Figure 6 This is a schematic diagram of the quick-release clamp in an embodiment of the present invention; Figure 7 This is a schematic diagram of step 1 in an embodiment of the non-destructive testing method for the airtightness of a liquid-floating gyroscope float according to the present invention; Figure 8 This is a schematic diagram of step 2 in an embodiment of the present invention.

[0021] The annotations in the attached figures are explained as follows: 01-Frame; 02-Float; 03-Connecting post; 04-Inflation nozzle; 05-Shaft tip; 010-Float; 1-Housing; 11-Hinge seat; 2-Quick release clamp; 3-Leak detection cover; 31-Hinge; 32-Handle; 4-Radial annular groove; 5-Axial through hole; 6-Silicone tube; 7-Glass tube; 8-Rubber tube; 9-V-shaped pad. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and exemplary embodiments.

[0023] Reference Figures 4 to 6 A non-destructive testing fixture for the airtightness of a liquid-floating gyroscope float includes a housing 1, a quick-release clamp 2, and a leak detection cover 3.

[0024] The outer wall of the housing 1 is provided with a radial annular groove 4 adapted to the quick-release clamp 2, and the housing 1 is provided with an axial through hole 5. A hinge seat 11 is provided on one side of the upper end of the housing 1, and a hinge member 31 corresponding to the hinge seat 11 is provided on one side of the leak detection cover 3. The leak detection cover 3 is hinged to the upper end of the housing 1 through the hinge member 31, the hinge seat 11 and the hinge shaft, and is used to seal the upper end of the axial through hole 5. A handle 32 is provided on the outer side of the leak detection cover 3 away from the hinge member 31. The quick-release clamp 2 is used to be set in the radial annular groove 4 to fix the lower end of the axial through hole 5 to the mass spectrometer to be connected, so that the axial through hole 5 between the leak detection cover 3, the housing 1 and the mass spectrometer forms a sealed cavity.

[0025] A non-destructive testing method for the airtightness of a liquid-float gyroscope float includes the following steps: Step 1: Before inflating float 010, use the helium injection method to check for leaks in float 010; Reference Figure 7 Place float 010 on V-shaped pad 9, and connect the float 010 inflation nozzle to the detection terminal of the helium mass spectrometer in sequence through silicone tube 6, glass tube 7, and rubber tube 8. Air is extracted from the inner cavity of float 010 using a helium mass spectrometer. Air is then blown into the sealing part of float 010 using a helium gun. If the sealing part leaks, helium enters the inner cavity of float 010. The helium mass spectrometer leak detector detects helium ions, and the leak rate of float 010 is determined based on the amount of helium ions detected. If the leakage rate of float 010 meets the standard, proceed to step 2; otherwise, it indicates that the airtightness of float 010 is abnormal, and the testing process ends. Step 2: After the float 010 is inflated and before final assembly, the float 010 is leak-tested using the helium pressure method; Reference Figure 8Place the float 010 into the axial through hole 5 of the above-mentioned liquid float gyroscope airtightness non-destructive testing tool, seal the upper end of the axial through hole 5 with the leak detection cover 3, connect the mass spectrometer at the lower end of the axial through hole 5, and set the quick release clamp 2 in the radial annular groove 4 to fix the lower end of the axial through hole 5 and the mass spectrometer. The leak detection cover 3, the housing 1 and the mass spectrometer form a sealed cavity through the axial through hole 5. The mass spectrometer evacuates the sealed cavity. Since the float 010 is filled with helium, once the sealed part of the float 010 leaks, helium enters the sealed cavity. The mass spectrometer detects helium ions and determines the leak rate of the float 010 based on the amount of helium ions detected. If the leakage rate of float 010 meets the standard, proceed to step 3; otherwise, it indicates that the airtightness of float 010 is abnormal, and the testing process ends. Step 3: Debug the liquid-float gyroscope and check for leaks in float 010 before delivery; Step 3.1: After calibrating the sensitive axis of the liquid-floating gyroscope (see CN114166244A), make the positive direction of the SA axis of the liquid-floating gyroscope parallel to the direction of gravitational acceleration and upward, and the OA axis horizontally northward. After stabilizing for 10 minutes, rotate the liquid-floating gyroscope 90° around the OA axis so that the positive direction of IA is parallel to the direction of gravitational acceleration and upward, and the OA axis horizontally northward. Immediately and continuously collect the gyroscope drift output for 120 minutes and plot the corresponding liquid-floating gyroscope output curve. Step 3.2: Determine whether the output curve of the liquid-floated gyroscope obtained in Step 3.1 meets the preset requirements; if it does, proceed to Step 3.3; otherwise, it indicates that the airtightness of float 010 is abnormal, and the detection process ends. Step 3.3: Continue to continuously rotate the liquid-floating gyroscope after step 3.1 to collect random drift data of fixed positions in multiple attitudes of the liquid-floating gyroscope, and plot the corresponding output curves of the liquid-floating gyroscope, specifically as follows: Step 3.3.1: Rotate the liquid-floating gyroscope 90° around the OA axis so that the positive direction of SA is parallel to the direction of gravitational acceleration and downward, and the OA axis is horizontal and northward. Immediately and continuously collect the gyroscope drift output for 120 minutes and plot the corresponding liquid-floating gyroscope output curve. Step 3.3.2: Rotate the liquid-floating gyroscope 90° around the OA axis so that the positive direction of IA is parallel to the direction of gravitational acceleration and downward, and the OA axis is horizontal and northward. Immediately and continuously collect the gyroscope drift output for 120 minutes and plot the corresponding liquid-floating gyroscope output curve. Step 3.3.3: Rotate the liquid-floating gyroscope 90° around the OA axis so that the positive direction of SA is parallel to the direction of gravitational acceleration and upward, and the OA axis is horizontal and northward. Immediately and continuously collect the gyroscope drift output for 120 minutes and plot the corresponding liquid-floating gyroscope output curve. Step 3.3.4: Rotate the liquid-floating gyroscope 90° around the OA axis so that the positive direction of IA is parallel to the direction of gravitational acceleration and upward, and the OA axis is horizontal and northward. Immediately and continuously collect the gyroscope drift output for 120 minutes and plot the corresponding liquid-floating gyroscope output curve. Step 3.4: Determine whether the output curves of the liquid-floated gyroscope obtained in Step 3.3 all meet the preset requirements; if they do, proceed with Step 3.3; otherwise, it indicates that the airtightness of float 010 is abnormal, and the detection process ends. In steps 3.1 and 3.3, the data acquisition frequency is 1 data point per second; In steps 3.2 and 3.4, the preset requirements are: the change in gyroscope drift output is significantly monotonically changing within the first 1 minute, and the change in the zero point value of gyroscope output is no greater than 0.0005 mA thereafter, and the standard deviation σ of gyroscope drift output within the first 120 minutes is no greater than 0.05° / h. Step 4: During the use of the liquid-float gyroscope, check the float 010 for leaks; After the liquid-floating gyroscope is installed and calibrated, when the liquid-floating gyroscope is delivered to the inertial assembly for use, the gyroscope mounting plate is pressed against the positioning pin to realize the transformation between the coordinate system of the liquid-floating gyroscope and the coordinate system of the inertial assembly; combined with the test position and results of the inertial assembly, the airtightness of float 010 is judged by the methods in steps 3.3 and 3.4.

[0026] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. For those skilled in the art, modifications can be made to the specific technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. However, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions protected by the present invention.

Claims

1. A non-destructive testing method for the airtightness of a liquid-float gyroscope float, characterized in that, The steps include the following: Step 1: Before the float (010) is filled with gas, the float (010) is leak-tested using the helium injection method; and the leak rate of the float (010) is determined based on the amount of inert gas detected in the float (010). If the leak rate meets the standard, proceed to Step 2; otherwise, it indicates that the airtightness of the float (010) is abnormal, and the testing process ends. Step 2: After the float (010) is inflated and before final assembly, the float (010) is leak-tested. The float (010) is placed in a sealed cavity, the sealed cavity is evacuated by a mass spectrometer, and the leakage rate of the float (010) is determined based on the amount of inert gas detected in the sealed cavity. If the leakage rate of float (010) meets the standard, proceed to step 3; otherwise, it indicates that the airtightness of float (010) is abnormal, and the detection process ends. Step 3: Before debugging and delivering the liquid-float gyroscope, perform a leak test on the float (010); Step 3.1: After calibrating the sensitive axis of the liquid-floating gyroscope, make the positive direction of the SA axis of the liquid-floating gyroscope parallel to the direction of gravitational acceleration and upward, and the OA axis horizontally northward. After stabilizing for at least 10 minutes, rotate the liquid-floating gyroscope 90° around the OA axis so that the positive direction of the IA axis is parallel to the direction of gravitational acceleration and upward, and the OA axis horizontally northward. Immediately and continuously collect the gyroscope drift output for 120 min to 150 min, and plot the corresponding liquid-floating gyroscope output curve. Step 3.2: Determine whether the output curve of the liquid-floated gyroscope obtained in Step 3.1 meets the preset requirements; if it does, proceed to Step 3.3; otherwise, it indicates that the airtightness of the float (010) is abnormal, and the detection process ends. Step 3.3: Continue to continuously rotate the liquid-floating gyroscope after step 3.1 to collect the random drift of the fixed position of the liquid-floating gyroscope in multiple attitudes, and plot the corresponding output curve of the liquid-floating gyroscope; Step 3.4: Determine whether the output curves of the liquid-floated gyroscope obtained in Step 3.3 all meet the preset requirements; if they do, proceed to Step 4; otherwise, it indicates that the airtightness of the float (010) is abnormal, and the detection process ends. Step 4: Check the float (010) for leaks during the use of the liquid-floating gyroscope; When the liquid-floating gyroscope is delivered to the inertial assembly for use, the gyroscope mounting plate is pressed against the positioning pin to realize the transformation between the coordinate system of the liquid-floating gyroscope and the coordinate system of the inertial assembly; combined with the test position and results of the inertial assembly, the airtightness of the float (010) is judged by the methods in steps 3.3 and 3.

4.

2. The non-destructive testing method for the airtightness of a liquid-floating gyroscope float according to claim 1, characterized in that: In step 3.3, the multiple attitudes include the positive SA axis direction being parallel to the gravitational acceleration direction and downward, the positive IA axis direction being parallel to the gravitational acceleration direction and downward, the positive SA axis direction being parallel to the gravitational acceleration direction and upward, and the positive IA axis direction being parallel to the gravitational acceleration direction and upward.

3. The method for non-destructive testing of the airtightness of a liquid-floating gyroscope float according to claim 2, characterized in that, Step 3.3 specifically involves: Step 3.3.1: Rotate the liquid-floating gyroscope 90° around the OA axis so that the positive direction of SA is parallel to the direction of gravitational acceleration and downward, and the OA axis is horizontal and northward. Immediately and continuously collect the gyroscope drift output for 120 min to 150 min, and plot the corresponding liquid-floating gyroscope output curve. Step 3.3.2: Rotate the liquid-floating gyroscope 90° around the OA axis so that the positive direction of IA is parallel to the direction of gravitational acceleration and downward, and the OA axis is horizontal and northward. Immediately and continuously collect the gyroscope drift output for 120 min to 150 min, and plot the corresponding liquid-floating gyroscope output curve. Step 3.3.3: Rotate the liquid-floating gyroscope 90° around the OA axis so that the positive direction of SA is parallel to the direction of gravitational acceleration and upward, and the OA axis is horizontal and northward. Immediately and continuously collect the gyroscope drift output for 120 min to 150 min, and plot the corresponding liquid-floating gyroscope output curve. Step 3.3.4: Rotate the liquid-floating gyroscope 90° around the OA axis so that the positive direction of IA is parallel to the direction of gravitational acceleration and upward, and the OA axis is horizontal and northward. Immediately and continuously collect the gyroscope drift output for 120 min to 150 min, and plot the corresponding liquid-floating gyroscope output curve.

4. The non-destructive testing method for the airtightness of a liquid-floating gyroscope float according to claim 3, characterized in that: In steps 3.1 and 3.3, the acquisition frequency is 1 data point per second; in steps 3.2 and 3.4, the preset requirements are: the gyroscope drift output change is significantly monotonically within the first 1 to 2 minutes, and the change in the zero point value of the gyroscope output is no greater than 0.0005 mA thereafter, and the standard deviation σ of the gyroscope drift output within the first 120 minutes is no greater than 0.05° / h.

5. A non-destructive testing method for the airtightness of a liquid-floating gyroscope float according to any one of claims 1 to 4, characterized in that: In step 1, the method of using helium spraying to detect leaks in the float (010) before inflation is as follows: the float (010) is placed on a V-shaped pad (9), and the inflation nozzle of the float (010) is connected to the detection terminal of the helium mass spectrometer in sequence through the silicone tube (6), glass tube (7), and rubber tube (8); the air in the inner cavity of the float (010) is extracted by the helium mass spectrometer, and air is blown into the sealing part of the float (010) by the helium gun. Once the sealing part leaks, helium enters the inner cavity of the float (010), and the helium mass spectrometer detects helium protons. The leak rate of the float (010) is determined based on the amount of helium protons detected.

6. The non-destructive testing method for the airtightness of a liquid-floating gyroscope float according to claim 1, characterized in that: The sealed cavity includes a housing (1), a quick-release clamp (2), and a leak detection cover (3); The outer wall of the housing (1) is provided with a radial annular groove (4) that is adapted to the quick-release clamp (2), and the housing (1) is provided with an axial through hole (5); one side of the leak detection cover (3) is hinged to the upper end of the housing (1); the quick-release clamp (2) is set in the radial annular groove (4) to fix the lower end of the axial through hole (5) to the mass spectrometer to be connected.

7. The non-destructive testing method for the airtightness of a liquid-floating gyroscope float according to claim 6, characterized in that: A hinge seat (11) is provided on one side of the upper end of the housing (1), and a hinge member (31) corresponding to the hinge seat (11) is provided on one side of the leak detection cover (3). The leak detection cover (3) is hinged to the upper end of the housing (1) through the hinge member (31), the hinge seat (11) and the hinge shaft. A handle (32) is provided on the outside of the leak detection cover (3) away from the hinge member (31).

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