A process method for aerodynamic moment correction of dynamically tuned gyroscopes

Abstract

The present invention provides a method for correcting the aerodynamic moment of a dynamically tuned gyro. By adding a special-shaped compensation ring (i.e., an inclined ring), the change in aerodynamic force is compensated, and the disturbing moment from the gas acting on the flywheel is eliminated to ensure the stable performance of the gyro.

Description

Technical Field

[0001] The present invention belongs to the technical field of dynamic tuning gyro assembly and adjustment, and particularly relates to a process method for correcting aerodynamic torque of a dynamic tuning gyro. Background Art

[0002] When the gyro rotor of a dynamic tuning gyro rotates at a high speed, the axial and radial clearances are respectively formed between the flywheel and the front cover of the gyro, between the torque coil and the inner ring of the flywheel, between the limiting mechanism and the flywheel, and between the signal core coil and the flywheel. The influence of aerodynamic force on these air gaps comes from the following two aspects:

[0003] One is to generate a frictional resistance torque on the rotation of the flywheel, and the vector is along the opposite direction of the self-rotation axis of the flywheel. It is the main factor for generating the time constant.

[0004] The second is the torque caused by the air density wedge on the rotor. When the flywheel rotor deflects relative to the housing, the axial and radial clearances will be uneven, thereby generating aerodynamic torque. Due to the compressibility of air, the air density is the largest at the smallest clearance, and the corresponding pressure is also the largest at this time. The method of adding a ring on the front cover of the gyro is more closely related to the air density wedge. If the internal air conditions of the gyro do not change, the above torques will not change, that is, the drift remains unchanged, and compensation can be carried out in subsequent components and systems. However, during the use process, when the gyro has temperature changes such as heating and cooling, this will cause changes in the air gap size, pressure, gas viscosity, etc., and the gas adsorbed on the surface of the parts will overflow, and some components in the bearing grease will volatilize, resulting in irreversible changes in the internal gas, causing a unilateral change trend in the drift during the first start and the drift during successive starts.

[0005] In addition, the structural characteristics of the dynamic tuning gyro itself also determine that its flywheel is directly exposed to the surrounding gas, and any disturbing torque from the gas on the flywheel will directly act on the gyro rotor, thereby generating corresponding gyro drift.

[0006] In view of the above situation, it is necessary to explore a process method for correcting the aerodynamic torque of a dynamic tuning gyro to reduce the influence of changes in the properties of the gas medium on the gyro drift. Summary of the Invention

[0007] The purpose of the present invention is to solve the deficiencies of the prior art and provide a process method for correcting the aerodynamic torque of a dynamic tuning gyro.

[0008] Conception of the present invention:

[0009] The researchers of the present invention analyzed that the power-tuned gyro rotor has many air gaps with different shapes such as width, depth, etc. Due to the uneven texture of the material, errors in machining and assembly, their asymmetry relative to the rotor in space is caused. Due to the hydrodynamic wedge and gas density wedge effects of the airflow in the air gap, an aerodynamic torque (aerodynamic moment) directly acting on the gyro rotor is generated.

[0010] Therefore, it is proposed to correct the aerodynamic torque (aerodynamic moment) by pressing a pit on the front cover of the gyro or adding a special-shaped compensation ring inside the front cover of the gyro, and then changing the local air gap between the front cover of the gyro and the rotor to generate a compensating gas dynamic torque; because the principles of these two compensation methods are exactly the same, so the present invention only involves compensating for the change of aerodynamic force by adding a special-shaped compensation ring (i.e., an inclined ring), eliminating the interference torque from the gas to the flywheel, so as to ensure the stable performance of the gyro.

[0011] To achieve the above object, the technical solution provided by the present invention is:

[0012] A process method for correcting the aerodynamic torque of a power-tuned gyro, which is essentially a method of selecting a suitable compensation ring (i.e., the position of the high point of the compensation ring) to achieve this purpose when the influence of the change of the gas medium property on the gyro drift cannot be reduced by rotating the front cover of the gyro. Its special features include the following steps:

[0013] 1) Preliminary selection of the compensation ring

[0014] 1.1) Mark the position on the outer peripheral surface of the front cover of the gyro opposite to the gyro positioning pin.

[0015] 1.2) After the gyro operates in a closed loop, place the marked position on the front cover of the gyro in the east direction and the south direction respectively for the air pressure sensitivity test of the gyro (where the gyro positioning pin always points to the east direction); according to the sum of the change amounts of the constant components of the air pressure sensitivity test of the X-axis and Y-axis of the gyro in each direction (specifically, the value of Δω x +Δω Y in the air pressure sensitivity curve graph in each direction), determine the difference in size between the high and low points of the compensation ring.

[0016] 1.3) Select the corresponding compensation ring according to the difference in size between the high and low points obtained in step 1.2), clean the compensation ring, and then adhesively bond it coaxially inside the front cover of the gyro, where the high point of the compensation ring faces the marked position on the front cover of the gyro.

[0017] 2) Check the correction effect of the compensation ring

[0018] Place the scribed mark on the front cover of the gyroscope in the south direction or the east direction and conduct the air pressure sensitivity test again. According to the air pressure sensitivity curve change trend diagram when the high point of the compensation ring rotates counterclockwise from the south direction to the east direction or the air pressure sensitivity curve change trend diagram when the high point of the compensation ring rotates clockwise from the east direction to the south direction; adjust and test the correction effect of the compensation ring selected in step 1):

[0019] If the Δω of both axes is ≥ 0.1 (i.e., the dynamically tuned gyroscope senses two axial directions - the X-axis and the Y-axis, Δω refers to the change in the constant component of the gyroscope, if it is Δω x then it refers to the change in the constant component of the X-axis, Δω Y refers to the change in the constant component of the Y-axis), rotate the front cover according to the change trend of the air pressure sensitivity curve until the Δω of at least one axis is < 0.1; when the Δω of one axis is < 0.1, compare the air pressure sensitivity curve at this time with the curve without the ring to see whether the Δω of the other axis and the Δω without the ring have the same sign or different signs (Δω is a vector, and the positive and negative signs represent directions); if they have the same sign, it means that the difference between the high and low points of the compensation ring is insufficient and the aerodynamic torque correction is not enough, and it is necessary to grind the low point of the compensation ring or replace a compensation ring with a larger difference between the high and low points, and recheck the correction effect; if they have different signs, it means that the aerodynamic torque correction is too large, and it is necessary to grind the high point of the compensation ring or replace a compensation ring with a smaller difference between the high and low points, and recheck the correction effect;

[0020] If the Δω of both axes is < 0.1, it means that the selected compensation ring is appropriate and the aerodynamic torque correction can be carried out;

[0021] 3) Weld and fix the compensation ring selected in step 2).

[0022] In step 1.2), the difference in size between the high and low points of the initially selected compensation ring is arbitrarily selected between the values obtained by adding the change amounts of the constant components of the air pressure sensitivity test curves of the X-axis and Y-axis of the gyroscope in two directions;

[0023] Furthermore, in step 1.2), after adhesively bonding the compensation ring coaxially inside the front cover of the gyroscope with Loctite glue, use acetone to wipe off the overflowed glue.

[0024] Furthermore, the compensation ring is an inclined circular ring and is made of the same material as the front cover of the gyroscope.

[0025] The principle of the present invention:

[0026] The torque of the gas medium on the rotor is caused by the non-uniformity of the gap between the rotor and the housing and the non-coincidence of the rotor rotation axis and the motor drive axis, and is only related to the properties of the gas medium when the gyro structure is fixed. Aerodynamic torque correction is achieved by pasting an inclined ring on the front cover of the gyro to change the local air gap between the front cover of the gyro and the rotor. When the gyro rotor rotates, the flowing gas medium generates an additional aerodynamic torque to compensate for this resultant torque, and the torque originally generated by the gas medium on the rotor cancels out the newly generated torque, thus achieving the purpose of reducing the influence of changes in the properties of the gas medium on the gyro drift.

[0027] The advantages of the present invention are as follows:

[0028] The present invention seeks to reduce the causes of changes in the air pressure sensitivity curve. By changing the local air gap between the front cover of the gyro and the rotor, a compensating gas dynamic torque is generated to reduce the drift caused by the gas dynamic torque and improve the random drift accuracy of the dynamically tuned gyro; reduce the drift caused by changes in the gas dynamic torque due to temperature changes during gyro operation; reduce the gyro drift caused by changes in the properties of the gas medium during long-term operation of the gyro and improve the repeatability of the gyro drift. Brief Description of the Drawings

[0029] Figure 1 It is the air pressure sensitivity curve when the front cover of the gyro points east without pasting the ring;

[0030] Figure 2 It is the air pressure sensitivity curve when the front cover of the gyro points south without pasting the ring;

[0031] Figure 3 It is the schematic diagram of the bonding position of the compensation ring of the present invention;

[0032] Markings in the figure:

[0033] 1 - Front cover of the gyro, 2 - Compensation ring, 3 - Scratch mark;

[0034] Figure 4 It is the air pressure sensitivity curve when the front cover of the gyro points south after pasting a 0.4 mm compensation ring;

[0035] Figure 5 It is the trend chart of the change of the air pressure sensitivity curve when the high point of the compensation ring rotates counterclockwise from the south direction to the east direction;

[0036] Figure 6 It is the trend chart of the change of the air pressure sensitivity curve when the high point of the compensation ring rotates clockwise from the east direction to the south direction;

[0037] Figure 7 It is Figure 4 The air pressure sensitivity curve when the front cover of the gyro rotates 30° eastward after pasting the compensation ring;

[0038] Figure 8 For Figure 4 The air pressure sensitivity curve of the gyro front cover rotating 50° eastward after pasting the compensation ring;

[0039] Figure 9 It is the result of the random drift test of the gyro at a fixed position starting once under 40 mmHg. Specific implementation manners

[0040] The following further describes in detail the content of the present invention in conjunction with the accompanying drawings and specific embodiments:

[0041] A process method for aerodynamic moment correction of a dynamically tuned gyro. For medium and high-precision gyros (random drift < 0.02° / h), the internal aerodynamic moment of the gyro can be controlled by pasting a compensation ring on the gyro front cover to ensure that the random drift of the gyro meets the requirements. The specific correction method is as follows:

[0042] 1. Mark the position on the outer peripheral surface of the gyro front cover opposite to the gyro positioning pin by scribing;

[0043] 2. After the gyro enters the working state, place the scribed marks on the gyro front cover in the east direction and the south direction respectively for the air pressure sensitivity test of the gyro. According to the sum of the change amounts of the constant components of the air pressure sensitivity test curves of the X-axis and Y-axis of the gyro in each direction, determine the difference in dimensions between the high and low points of the compensation ring (as shown in Figures 1 and 2, when the scribed mark on the gyro front cover points to the east direction, Δω₁ + Δω₂ is 0.4473, and when the scribed mark on the gyro front cover points to the south direction, Δω₃ + Δω₄ is 0.3858). In this embodiment, the gyro selects the difference in dimensions between the high and low points of the compensation ring to be 0.4 mm. Figure 1 、 Figure 2 As shown in Figures 1 and 2, when the scribed mark on the gyro front cover points to the east direction, Δω₁ + Δω₂ is 0.4473, and when the scribed mark on the gyro front cover points to the south direction, Δω₃ + Δω₄ is 0.3858. In this embodiment, the gyro selects the difference in dimensions between the high and low points of the compensation ring to be 0.4 mm. x +Δω Y For 0.4473, when the scribed mark on the gyro front cover points to the south direction, Δω x +Δω Y Is 0.3858). In this embodiment, the gyro selects the difference in dimensions between the high and low points of the compensation ring to be 0.4 mm.

[0044] 2. Select the corresponding compensation ring. After cleaning the compensation ring, paste it coaxially inside the gyro front cover using Loctite glue, and the high point of the compensation ring faces the scribed mark on the gyro front cover, as shown in Figure 3. Note: When pasting, it should be ensured that the compensation ring is firmly bonded to the gyro front cover, ensuring that the compensation ring is coaxial with the gyro front cover without obvious deviation; after bonding, acetone can be used to wipe off the overflowed glue; after testing, the marks can be erased. Figure 3 As shown in Figure 3. Note: When pasting, it should be ensured that the compensation ring is firmly bonded to the gyro front cover, ensuring that the compensation ring is coaxial with the gyro front cover without obvious deviation; after bonding, acetone can be used to wipe off the overflowed glue; after testing, the marks can be erased.

[0045] 3. Place the scribed mark on the gyro front cover in the south direction for the air pressure sensitivity test of the gyro, as shown in Figure 4, to verify whether the compensation ring is appropriate. Figure 4 As shown in Figure 4, to verify whether the compensation ring is appropriate.

[0046] 4. According to the change trend of the air pressure sensitivity curve when the high point of the compensation ring rotates counterclockwise from the south direction to the east direction (see Figure 5) When the high point of the compensation ring rotates counterclockwise from the east direction to the south direction, the change trend of the barometric sensitivity curve (see Figure 6 ), and the correction effect of the pasted compensation ring is inspected:

[0047] If the Δω of both axes is greater than or equal to 0.1, then rotate the gyro front cover according to the change trend of the barometric sensitivity curve until Δω of at least one axis < 0.1. When Δω of one axis < 0.1, compare the barometric sensitivity curve at this time with the barometric sensitivity curve without the ring, and see whether the Δω of the other axis has the same sign as the Δω without the ring; if they have the same sign, it means that the difference between the high and low points of the ring is insufficient and the aerodynamic moment correction is not enough, and it is necessary to grind the low point of the ring or replace a ring with a larger difference between the high and low points, and re-inspect the correction effect; if they have different signs, it means that the aerodynamic moment correction is too large, and it is necessary to grind the high point of the ring or replace a ring with a smaller difference between the high and low points, and re-inspect the correction effect. For the gyro of this embodiment, first rotate the gyro front cover from south to east by 30°, and obtain the barometric sensitivity curve as shown in Figure 7 , and then continue to rotate by 20°, and obtain the barometric sensitivity curve as shown in Figure 8 .

[0048] According to Figure 8 shown, during the process where the barometric pressure is approximately 41 mmHg to 70 mmHg, the change of gyro ω x , ω y is relatively small and tends to be a straight line, which is the least sensitive barometric pressure section. Select the front end of 40 mmHg of the straight line part of ω x , ω y to conduct a fixed-position one-time start random drift test (during the operation of the gyro, it is in a closed space, and the heat loss generated by the motor operation will cause the temperature in the closed space where the gyro operates to rise, and the barometric pressure will increase accordingly. Therefore, 40 mmHg is selected, and after the increase, it is basically in the non-sensitive barometric pressure section of 41 mmHg to 70 mmHg). The test results are as shown in Figure 9 . Since the technical requirement of the dynamically tuned gyroscope in the example stipulates that the stable operation time is 5 min, the gyro fixed-position one-time start random drift test starts collecting data from 5 min to 60 min, and the results are as follows.

[0049] From Figure 9 the test results, it can be seen that S y = 0.002952, S x = 0.000875. It can be seen that the fixed-position one-time start random drift of the X-axis and Y-axis both meet the requirement of S < 0.01 for this process; among them, S y is the random drift accuracy of the dynamically tuned gyroscope during the fixed-position one-time start random drift of the Y-axis; S x is the random drift accuracy of the dynamically tuned gyroscope during the fixed-position one-time start random drift of the X-axis.

[0050] Due to manufacturing and assembly errors, the gaps between the gyro rotor (moving part) and the stationary parts such as the housing, torque generator, and signal generator are uneven in space. Due to the effects of the airflow hydrodynamic wedge and gas density wedge in the air gap, a dynamic pressure torque exists on the gyro rotor.

[0051] According to the observation of the gyro production process, under the requirement that the random drift accuracy is higher than 0.02° / h, the correction of the gas dynamic torque is an essential step. The fixing method of the compensation ring should first be bonded, and after determining the size of the compensation ring (i.e., the difference in dimensions between the high point and the low point of the compensation ring) and the angle (the angular position of the compensation ring (including the front cover) relative to the rotation of the gyroscope, such as Figure 7 as shown by 300°, Figure 8 as shown by 320°), it is directly fixed by laser welding. After the aerodynamic torque correction, the random drift of the gyro can remain stable within a certain fluctuation range of the internal air pressure, which has a positive effect on maintaining the service life of the gyro. After compensation by this method, the gyro accuracy can reach 0.005° / h. Under medium and low-precision usage conditions, this method can also be used for compensation and correction to correct the constant value of the gyro and reduce the scrap rate of parts.

[0052] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of the present invention.

Claims

1. A method for correcting aerodynamic torque of a dynamically tuned gyro, comprising the following steps: 1) Preliminary selection of compensation ring 1.1) Mark a line at the position on the outer peripheral surface of the gyro front cover opposite to the gyro positioning pin. 1.2) After the gyro operates in a closed-loop mode, place the marked lines on the gyro front cover in the east and south directions respectively to conduct the air pressure sensitivity test of the gyro. Determine the difference in height between the high and low points of the compensation ring according to the sum of the change amounts of the constant value components of the air pressure sensitivity test curves of the X-axis and Y-axis of the gyro in each direction. 1.3) Select the corresponding compensation ring according to the difference in height between the high and low points obtained in step 1.2), and adhesively bond the compensation ring coaxially inside the gyro front cover, where the high point of the compensation ring faces the marked line on the gyro front cover. 2) Adjust and inspect the correction effect of the compensation ring. Place the marked line on the gyro front cover in the south or east direction again to conduct the air pressure sensitivity test. According to the change trend diagram of the air pressure sensitivity curve when the high point of the compensation ring rotates counterclockwise from the south direction to the east direction or the change trend diagram of the air pressure sensitivity curve when the high point of the compensation ring rotates clockwise from the east direction to the south direction, adjust and inspect the correction effect of the compensation ring selected in step 1): If Δω of both axes is ≥ 0.1, rotate the gyro front cover according to the change trend of the air pressure sensitivity curve until Δω of at least one axis is < 0.1; when Δω of one axis is < 0.1, compare the current air pressure sensitivity curve with the air pressure sensitivity curve without the ring to see whether Δω of the other axis has the same sign or the opposite sign as that without the ring; if they have the same sign, it means that the difference between the high and low points of the compensation ring is insufficient and the aerodynamic torque correction is not enough, and it is necessary to grind the low point of the compensation ring or replace a compensation ring with a larger difference between the high and low points, and re-inspect the correction effect; if they have the opposite sign, it means that the aerodynamic torque correction is too large, and it is necessary to grind the high point of the compensation ring or replace a compensation ring with a smaller difference between the high and low points, and re-inspect the correction effect. If Δω of both axes is < 0.1, it means that the selected compensation ring is appropriate and the aerodynamic torque correction can be carried out. 3) Weld and fix the compensation ring selected in step 2).

2. According to the aerodynamic torque correction process method of the dynamically tuned gyro as described in claim 1, it is characterized in that: In step 1.2), the difference in height between the high and low points of the initially selected compensation ring is selected between the sum of the change amounts of the constant value components of the air pressure sensitivity test curves of the X-axis and Y-axis of the gyro in two directions.

3. According to the aerodynamic torque correction process method of the dynamically tuned gyro as described in claim 2, it is characterized in that: In step 1.2), after adhesively bonding the compensation ring coaxially inside the gyro front cover with Loctite glue, use acetone to wipe off the overflowed glue.

4. According to the aerodynamic torque correction process method of the dynamically tuned gyro as described in any one of claims 1 - 3, it is characterized in that: The compensation ring is an inclined circular ring.

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