A method for selecting parameters of inertial vibration damper

Abstract

A shock absorber selection method for an inertial navigation component can make a shock absorption system meet the use requirements by matching the performance parameters of a single shock absorber. According to the current installation method of the shock absorber, a specific measurement method of the height difference is provided, and a method for determining the static deformation and the static stiffness is determined. Based on the current method, a height size requirement range for shock absorber size matching and a stiffness matching requirement range for shock absorber size matching are proposed, which is not limited to the eight-point installation matching method, has a clear method flow, and is flexible in selection.

Description

Technical Field

[0001] The invention relates to a method for selecting parameters of an inertial group vibration damper, and belongs to the field of design and selection of laser inertial navigation components. Background Art

[0002] As one of the main devices of the control system, the main working principle of the laser inertial navigation unit is to use laser gyroscopes and quartz accelerometers as inertial sensitive components to measure the carrier's speed, attitude and other information in real time, providing a basis for the control system to perform navigation solutions. The strapdown inertial navigation system has the characteristics of simple structure, long service life, strong adaptability to mechanical environment, and higher reliability. The laser gyroscope and the laser strapdown inertial navigation system composed of it represent the future development direction of high-precision and high-reliability inertial measurement devices, and have become the core guidance and control equipment of international space launch vehicles, aircraft, spacecraft, missile weapons and other systems.

[0003] During the flight, the laser inertial group will be subjected to various aerodynamic forces and strong vibration excitations from the engine. These vibration components will cause large deviations in the attitude and position information output by the laser inertial group. The commonly used method at present is to reduce the impact of vibration through vibration absorbers, but there are also many problems, such as the coupling problem of linear vibration and angular vibration, and the problem of excessive horizontal difference of static inertial instruments.

[0004] Based on years of production experience, it is found that the vibration absorber selection parameters are one of the important factors affecting the accuracy of the laser inertial group. The current vibration absorber selection method is to calibrate the whole product and perform vibration tests to determine the horizontal difference and the consistency of the vibration absorber resonant frequency. The process is cumbersome and affects the production process. In addition, there is a risk of damage to the inertial instrument due to vibration. Summary of the invention

[0005] The technical problem solved by the present invention is: in view of the problems that the traditional shock absorber selection method in the current prior art is cumbersome process and slow generation process, a method for selecting parameters of an inertial group shock absorber is proposed, which involves calibrating and vibration testing the entire product.

[0006] The present invention solves the above technical problems by the following technical solutions:

[0007] A method for selecting parameters of an inertial group shock absorber, the steps are as follows:

[0008] (1) Perform an appearance inspection on the shock absorber and select shock absorber products that have no surface defects and meet the size requirements;

[0009] (2) Install the selected shock absorber on a special tooling, set measurement point distribution positions on the surface of the shock absorber, and use a measuring instrument that meets the accuracy requirements to measure the height difference parameters between the installation surface and the measurement surface of the shock absorber at all measurement point distribution positions;

[0010] (3) Install the shock absorber on the static stiffness test fixture and fix them together on the static stiffness tester. Repeat the preloading and unloading tests twice in the load-bearing direction of the shock absorber. During the third preloading, the load peak is maintained for a specified time and then gradually unloaded. Record the deformation values ​​of the distribution positions of each measuring point on the shock absorber at different loads during the three preloading and unloading tests;

[0011] (4) calculating the average deformation value of the same measuring point distribution position in the same preloading and unloading test according to the deformation value obtained in step (3), as the static deformation of the shock absorber at that point;

[0012] (5) Calculate the static stiffness of the shock absorber;

[0013] (6) Based on the data obtained in step (3), step (4), and step (5) and the specific requirements for shock absorber selection, determine whether the current shock absorber meets the selection criteria.

[0014] In the step (2), the method for measuring the height difference parameter is specifically as follows:

[0015] At all measurement point distribution locations, measure the height difference between the highest point, the lowest point and the mounting surface, and calculate the average original height and original height difference of the shock absorber based on the obtained height difference values. The calculation formula is as follows:

[0016]

[0017] ΔHo=Ho + -Ho -

[0018] Where, the height difference between the highest point of the measurement point distribution and the installation surface, and the height difference between the lowest point of the measurement point distribution and the installation surface.

[0019] In the step (3), the axial direction of the shock absorber is consistent with the compression or tension direction of the static stiffness tester.

[0020] In the step (3), in the preloading and unloading tests, the loading load range is 0 to 1.25 times the rated load of the shock absorber, and the loading speed is not greater than 8 mm / min.

[0021] In the step (3), during the third preloading, the load peak must be maintained for 30 seconds.

[0022] In the step (3), the deformation values ​​at the distribution positions of the measuring points at least include deformation values ​​under conditions of 0.9, 1, and 1.1 times the rated load.

[0023] In the step (5), the calculation formula of the static stiffness of the shock absorber is as follows:

[0024]

[0025] Where, P0 is the rated load of the shock absorber, ΔP is the static load increment, ΔX is the static deformation increment, X 0.9 , X 1.1 ——Static deformation at 0.9 and 1.1 times the rated load respectively.

[0026] The advantages of the present invention compared with the prior art are:

[0027] The present invention provides a method for selecting parameters of an inertial group shock absorber, which can match the performance parameters of a single shock absorber to make the shock absorption system meet the use requirements. According to the current installation method of the shock absorber, a specific method for measuring the height difference is provided, and a method for determining the static deformation and the static stiffness is determined. On the basis of the current method, a height dimension requirement range for shock absorber size matching can be proposed, and a shock absorber stiffness matching requirement range can be proposed. The method is not limited to the eight-point installation matching method, and the resonant frequency of the shock absorption system can be controlled by matching the static stiffness of the shock absorber. The method flow is clear and the selection is flexible. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A flow chart of the conventional shock absorber selection method provided for the invention;

[0029] Figure 2 A schematic diagram of the size and structure of the shock absorber provided for the invention;

[0030] Figure 3 A flow chart of a method for selecting a shock absorber for an inertial navigation assembly provided by the invention; DETAILED DESCRIPTION

[0031] A method for selecting parameters of inertial group shock absorber, for example Figure 1 The existing vibration damper selection process shown in the figure can be improved. The performance parameters of a single vibration damper can be matched to make the vibration damping system meet the use requirements. The installation methods of vibration dampers for inertial sensitive components of laser inertial groups are roughly divided into four or eight points symmetrically arranged on two relative installation surfaces of the components. The height size of the vibration damper should be matched, the deformation amount should be confirmed, and the stiffness should be calculated. Figure 3 As shown, the specific process is as follows:

[0032] (1) Perform an appearance inspection on the shock absorber and select shock absorber products that have no surface defects and meet the size requirements;

[0033] (2) Install the selected shock absorber on a special tooling, such as Figure 2 As shown, measuring points are distributed on the surface of the shock absorber, and the height difference parameters between the mounting surface and the measuring surface of the shock absorber are measured at all measuring points using measuring instruments that meet the accuracy requirements.

[0034] The specific method for measuring the height difference parameter is as follows:

[0035] At all measurement point distribution locations, measure the height difference between the highest point, the lowest point and the mounting surface, and calculate the average original height and original height difference of the shock absorber based on the obtained height difference values. The calculation formula is as follows:

[0036]

[0037] ΔHo=Ho + -Ho -

[0038] Where, the height difference between the highest point of the measurement point distribution and the installation surface, and the height difference between the lowest point of the measurement point distribution and the installation surface;

[0039] (3) Install the shock absorber on the static stiffness test fixture and fix them together on the static stiffness tester. The axial direction of the shock absorber is consistent with the compression or tension direction of the static stiffness tester. Repeat the preloading and unloading tests twice in the load-bearing direction of the shock absorber. During the third preloading, the load peak is maintained for a specified time and then gradually unloaded. Record the deformation values ​​of the distribution positions of each measuring point on the shock absorber at different loads during the three preloading and unloading tests;

[0040] Among them, in the preloading and unloading tests, the loading load range is 0 to 1.25 times the rated load of the shock absorber, and the loading speed is not more than 8mm / min; when preloading for the third time, it is necessary to maintain the load peak for 30s; the deformation values ​​of the distribution positions of each measuring point include at least the deformation values ​​under 0.9, 1, and 1.1 times the rated load;

[0041] (4) calculating the average deformation value of the same measuring point distribution position in the same preloading and unloading test according to the deformation value obtained in step (3), as the static deformation of the shock absorber at that point;

[0042] (5) Calculate the static stiffness of the shock absorber;

[0043] The calculation formula of the static stiffness of the shock absorber is as follows:

[0044]

[0045] Where, P0 is the rated load of the shock absorber, ΔP is the static load increment, ΔX is the static deformation increment, X 0.9 , X 1.1 ——Static deformation at 0.9 and 1.1 times the rated load respectively;

[0046] (6) Based on the data obtained in step (3), step (4), and step (5) and the specific requirements for shock absorber selection, determine whether the current shock absorber meets the selection criteria.

[0047] The following is further described in conjunction with specific embodiments:

[0048] In this embodiment, the installation and matching method of the eight-point vibration damper of the laser inertial group sensor component is as follows:

[0049] The surface of the shock absorber product should be free of scratches, degumming, tears or burrs, and the surface of the rubber material should be free of pores, cracks, aging, impurities and local defects; the surface of the metal material should be smooth, free of oil stains and excess rubber; the internal threads should be clean and complete, and the size should meet the requirements.

[0050] Install the shock absorber on a special tool and use a measuring instrument with an accuracy better than 0.01mm to measure the Figure 3 The height difference between the installation surface (surface A) and the measuring surface (surface B) shown in the figure, select 4 measuring points from the specific positions of the measuring surface (surface B) and the installation surface (surface A). After measurement, record the height difference values ​​Ho+ and Ho- between the highest point + and the lowest point - and the A surface.

[0051] Average original height: Original height difference: ΔHo=Ho + -Ho - .

[0052] Install a single shock absorber on the static stiffness test fixture and fix it on the static stiffness tester, keeping the axial direction of the shock absorber consistent with the compression (or stretching) direction of the static stiffness tester;

[0053] According to the national standard GB / T 15168, the secondary preloading and unloading tests are repeated in the load direction of the shock absorber. The load range is from zero to 1.25 times the rated load. The deformation of the shock absorber should be uniform and the loading rate should not be greater than 8mm / min.

[0054] The third time, load gradually from zero to 1.25 times of the rated load, hold for 30 seconds, and then gradually unload to zero, while recording the deformation values ​​of each point when loading and unloading (including at least 0.9 times, 1 times and 1.1 times of the rated load). Take the average deformation value (i.e. the average value of the deformation values ​​when loading and unloading at the same load) as the static deformation.

[0055] The static stiffness Ks of the shock absorber is calculated according to the following formula:

[0056]

[0057] Where, P0 is the rated load of the shock absorber, ΔP is the static load increment, ΔX is the static deformation increment, X 0.9 , X 1.1 ——Static deformation at 0.9 and 1.1 times the rated load respectively.

[0058] For the laser inertial group, a four-point vibration damper installation structure is adopted. Two vibration dampers from the same batch with a height difference △H of no more than 0.03mm on a single side are matched into a pair, and the total height of the two groups of vibration dampers after matching should meet H±0.1mm, and the height should be the distance between the highest point of the measuring surface and the mounting surface, and the static stiffness of the four vibration dampers is controlled within the range of ±1N·mm; For the laser inertial group, an eight-point vibration damper installation structure is adopted. Two vibration dampers from the same batch with a height difference △H of no more than 0.03mm on a single side are matched into a pair, and the total height of the two groups of vibration dampers after matching should meet H±0.1mm, and the height should be the distance between the highest point of the measuring surface and the mounting surface, and the static stiffness of the eight vibration dampers is controlled within the range of ±1N·mm; Try to select vibration dampers from the same batch for matching. If it is not possible to match in the same batch, you can match in different batches.

[0059] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

[0060] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A method for selecting a shock absorber for an inertial navigation assembly, characterized in that Here are the steps: (1) Perform an appearance inspection on the shock absorber and select shock absorber products that have no surface defects and meet the size requirements; (2) Install the selected shock absorber on a special tooling, set measurement point distribution positions on the surface of the shock absorber, and use a measuring instrument that meets the accuracy requirements to measure the height difference parameters between the installation surface and the measurement surface of the shock absorber at all measurement point distribution positions; (3) Install the shock absorber on the static stiffness test fixture and fix them together on the static stiffness tester. Repeat the preloading and unloading tests twice in the load-bearing direction of the shock absorber. During the third preloading, the load peak is maintained for a specified time and then gradually unloaded. Record the deformation values ​​of the distribution positions of each measuring point on the shock absorber at different loads during the three preloading and unloading tests; (4) calculating the average deformation value of the same measuring point distribution position in the same preloading and unloading test according to the deformation value obtained in step (3), as the static deformation of the shock absorber at the current measuring point; (5) Calculate the static stiffness of the shock absorber; (6) judging whether the current shock absorber meets the selection criteria based on the data obtained in steps (3), (4), and (5) and the specific requirements for shock absorber selection; In the step (2), the method for measuring the height difference parameter is specifically as follows: At all measurement point distribution locations, measure the height difference between the highest point, the lowest point and the mounting surface, and calculate the average original height and original height difference of the shock absorber based on the obtained height difference values. The calculation formula is as follows: ΔHo=Ho + -To - Where Ho + Ho is the height difference between the highest point of the measurement point distribution and the installation surface. - It is the height difference between the lowest point of the measurement point distribution and the installation surface.

2. The method for selecting a shock absorber for an inertial navigation assembly according to claim 1, characterized in that: In the step (3), the axial direction of the shock absorber is consistent with the compression or tension direction of the static stiffness tester.

3. The method for selecting a shock absorber for an inertial navigation assembly according to claim 1, characterized in that: In the step (3), in the preloading and unloading tests, the loading load range is 0 to 1.25 times the rated load of the shock absorber, and the loading speed is not greater than 8 mm / min.

4. The method for selecting a shock absorber for an inertial navigation assembly according to claim 1, characterized in that: In the step (3), during the third preloading, the load peak must be maintained for 30 seconds.

5. The method for selecting a shock absorber for an inertial navigation assembly according to claim 1, characterized in that: In the step (3), the deformation values ​​at the distribution positions of the measuring points at least include deformation values ​​under conditions of 0.9, 1, and 1.1 times the rated load.

6. The method for selecting a shock absorber for an inertial navigation assembly according to claim 1, characterized in that: In the step (5), the calculation formula of the static stiffness of the shock absorber is as follows: Where, P0 is the rated load of the shock absorber, ΔP is the static load increment, ΔX is the static deformation increment, X 0.9 , X 1.1 ——Static deformation at 0.9 and 1.1 times the rated load respectively.

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