High-resolution space camera secondary mirror gasket calibration method and system

Abstract

The invention relates to the technical field of spaceflight optical remote sensors, and particularly discloses a calibration method and system for a secondary mirror gasket of a high-resolution space camera, and the method comprises the following steps: 1, carrying out the calibration of a secondary mirror gasket to be repaired in a state that the secondary mirror gasket to be repaired is assembled in the high-resolution space camera; obtaining a first reference point test result of a measurement plane of a secondary mirror installation and adjustment auxiliary tool connected with the secondary mirror structure; 2, when the high-resolution space camera is in the optimal wave aberration state, obtaining a second reference point test result of the measurement plane of the secondary mirror installation and adjustment auxiliary tool connected with the secondary mirror structure; 3, comparing the first reference point test result with the second reference point test result, and calculating to obtain the required grinding thickness of the secondary mirror gasket; and fourthly, the secondary mirror gasket to be repaired is corrected based on the obtained grinding thickness of the secondary mirror gasket. The method is high in calibration efficiency, high in calibration precision and wide in application scene.

Description

Technical Field

[0001] The present invention relates to the technical field of aerospace optical remote sensors, and in particular to a method and system for calibrating a secondary mirror gasket of a high-resolution space camera. Background Art

[0002] High-resolution space cameras often include reflector elements such as primary mirrors and secondary mirrors. During optical design, the secondary mirror often has the highest installation accuracy requirements, and its three-axis linear positioning accuracy is required to be in the micron level, and the angle positioning accuracy is in the second level. Therefore, it is necessary to add a gasket between the secondary mirror and the mounting base, and achieve high-precision installation of the secondary mirror by grinding and adjusting the gasket. At present, the conventional method is to adjust the position of the secondary mirror to the optimal system wave aberration, and then use a feeler gauge or a gauge block to roughly measure the thickness of the secondary mirror gasket, and the measurement accuracy can only reach tens of microns. For example, a Chinese patent with the publication number CN107608089B and the name of a discrete space camera secondary mirror precision adjustment and fixing method mentions a secondary mirror gasket calibration method. The idea of ​​this method is to preliminarily calibrate the thickness d1 of the secondary mirror gasket based on the feeler gauge, and use the thickness d as a reference value to make a gradient wedge-shaped gasket with a central thickness of d1 at each mounting point, cut the wedge-shaped gasket into several gaskets, and find the most suitable gasket combination through repeated trial assembly.

[0003] Although the above method makes the secondary mirror gasket production process relatively simple and improves the production efficiency of the secondary mirror gasket to a certain extent, it still has the following disadvantages: a) the feeler gauge calibration accuracy is low, and its calibration error will eventually affect the wedge-shaped gasket production accuracy; b) the gasket still needs to be repeatedly tested during the installation and adjustment process. The secondary mirror is often installed in a three-point form. If the number of discrete gasket groups made of wedge-shaped gaskets at a single installation point is n, then the total number of trial installation combinations can reach n3. The trial installation workload is huge, which affects the installation and adjustment efficiency; c) the final achievable secondary mirror positioning accuracy can reach 5μm, and the angle positioning accuracy can reach 5″. This value is still relatively large. For some systems with high requirements for secondary mirror installation, the resulting system wave aberration degradation is significant.

[0004] Based on this, technical personnel in this field urgently need to provide a new high-resolution space camera secondary mirror gasket calibration solution to overcome the technical problems existing in the above technical solutions. Summary of the invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defects existing in the above-mentioned prior art, thereby providing a method for measuring the thickness of the secondary mirror gasket of a high-resolution space camera and a calibration system.

[0006] A high-resolution space camera secondary mirror gasket calibration system, comprising: a high-resolution space camera, a secondary mirror gasket to be repaired, a secondary mirror assembly auxiliary tooling, a five-dimensional adjustment frame, a micrometer assembly, a plane mirror and a four-dimensional dynamic interferometer; The secondary mirror gasket to be repaired is detachably connected to the high-resolution space camera; One end of the secondary mirror assembly and adjustment auxiliary tooling is detachably connected to the secondary mirror structure in the high-resolution space camera, and the other end is a measuring plane that fits the micrometer component; The secondary mirror assembly and adjustment auxiliary tooling is detachably connected to the five-dimensional adjustment frame; Among them, the five-dimensional adjustment frame, four-dimensional dynamic interferometer and plane mirror work together to ensure that the high-resolution space camera is in the optimal state of wave aberration.

[0007] Preferably, the micrometer assembly is composed of three micrometers and a micrometer seat; The three dial indicators are all installed on the dial indicator stand.

[0008] Preferably, the measuring directions of the three micrometers are highly parallel.

[0009] A high-resolution space camera secondary mirror gasket calibration method is implemented based on a high-resolution space camera secondary mirror gasket calibration system. The calibration method comprises the following steps: Step 1: When the secondary mirror gasket to be repaired is assembled on the high-resolution space camera, obtain the first reference point test result of the measurement plane of the secondary mirror assembly auxiliary tooling connected to the secondary mirror structure; Step 2: When the high-resolution space camera is in an optimal state of wave aberration, obtain a second reference point test result of the measurement plane of the secondary mirror assembly auxiliary tooling connected to the secondary mirror structure; Step 3: Compare the first benchmark point test result and the second benchmark point test result to calculate the grinding thickness of the secondary mirror gasket; Step 4: Correct the secondary mirror gasket to be repaired based on the obtained grinding thickness of the secondary mirror gasket.

[0010] Preferably, step one specifically includes: S1. Build a primary and secondary mirror adjustment workbench, and ensure that the measurement axis of the four-dimensional dynamic interferometer on the primary and secondary mirror adjustment workbench is parallel to the optical axis of the high-resolution space camera, and the measurement axis of the four-dimensional dynamic interferometer coincides with the measurement point of the measurement plane; S2. Connect the secondary mirror gasket to be repaired to the high-resolution space camera; S3. The secondary mirror assembly auxiliary fixture is fixedly connected to the secondary mirror structure of the high-resolution space camera; S4. Use a micrometer to measure the initial position of each measuring point on the measuring plane, and record the first benchmark point test result and return to zero.

[0011] Preferably, step 2 specifically includes: S5. Disassemble the secondary mirror structure in the high-resolution space camera, and fix the secondary mirror structure to the five-dimensional adjustment frame through the secondary mirror adjustment auxiliary tooling; S6. Build a camera wave aberration test optical path based on a four-dimensional dynamic interferometer and a plane mirror, and adjust the spatial position of the secondary mirror structure through a five-dimensional adjustment frame to achieve the best wave aberration state for the optical image plane of the high-resolution space camera; S7. Use a micrometer to measure the displacement of each measuring point on the measuring plane after adjustment; S8. According to the displacement of each measuring point, the change in the positional relationship of the measuring plane is calculated as the result of the second reference point test.

[0012] Preferably, step three specifically includes: S9. Compare and calculate the first reference point test results and the second reference point test results to obtain the displacement of each measuring point and the deflection angle of the measuring plane in the change of the positional relationship of the measuring plane; S10. The grinding thickness of the secondary mirror gasket adapted to the secondary mirror mounting surface is calculated using the length L of the left and right end surfaces of the adjustment fixture, the displacement of each measuring point, and the deflection angle of the measuring plane in the change of the positional relationship of the measuring plane.

[0013] Preferably, the measuring points on the measuring plane are all edge measuring points, and there are three of them in total, which are compatible with the number and installation position of the micrometer.

[0014] The technical solution of the present invention has the following advantages: 1) High calibration efficiency: The parameters of the secondary mirror gasket to be repaired can be obtained with one measurement, without multiple measurements and adjustments, reducing the secondary mirror installation and adjustment time from days to hours; 2) High calibration accuracy: The present invention can achieve a positioning accuracy of the secondary mirror relative to the primary mirror of better than 3 μm and an angular positioning accuracy of better than 3″; 3) Wide application scenarios: The present invention can not only be applied to the assembly and adjustment of secondary mirror components of various types of high-resolution space cameras, but can also be promoted and applied to other optical component assembly and adjustment scenarios that also have high-precision assembly and adjustment requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 This is a schematic diagram of the structure of the high-resolution space camera secondary mirror gasket calibration system of the present invention; Figure 2 A three-dimensional schematic diagram of the secondary mirror assembly and adjustment auxiliary tooling structure in the secondary mirror gasket calibration system for a high-resolution space camera of the present invention; Figure 3It is a three-dimensional schematic diagram of the micrometer and micrometer stand structure in the high-resolution space camera secondary mirror gasket calibration system of the present invention.

[0017] Description of reference numerals: 1-high-resolution space camera, 2-secondary mirror structure, 3-secondary mirror gasket to be repaired, 4-secondary mirror assembly and adjustment auxiliary tooling, 401-measuring plane, 5-five-dimensional adjustment frame, 6-micrometer, 7-micrometer base, 8-plane mirror, 9-four-dimensional dynamic interferometer. DETAILED DESCRIPTION

[0018] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0020] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0021] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0022] Example 1 like Figure 1-3 The embodiment shown discloses a high-resolution space camera secondary mirror gasket calibration system, comprising: a high-resolution space camera 1, a secondary mirror gasket to be repaired 3, a secondary mirror assembly auxiliary tool 4, a five-dimensional adjustment frame 5, a micrometer assembly, a plane mirror 8 and a four-dimensional dynamic interferometer 9; The secondary mirror gasket 3 to be repaired is detachably connected to the high-resolution space camera 1; One end of the secondary mirror assembly and adjustment auxiliary tooling 4 is detachably connected to the secondary mirror structure 2 in the high-resolution space camera 1, and the other end is a measuring plane 401 that fits the micrometer component; The secondary mirror assembly and adjustment auxiliary tooling 4 is detachably connected to the five-dimensional adjustment frame 5; Among them, the five-dimensional adjustment frame 5, the four-dimensional dynamic interferometer 9 and the plane mirror 8 cooperate to ensure that the high-resolution space camera 1 is in the optimal state of wave aberration.

[0023] Specifically: like Figure 1 and 3 As shown, in this embodiment, the micrometer assembly is composed of three micrometers 6 and a micrometer seat 7; The three micrometer gauges 6 are all installed on the micrometer gauge base 7.

[0024] Furthermore, in this embodiment, the measuring directions of the three micrometers 6 are highly parallel.

[0025] like Figure 2 As shown, the secondary mirror assembly and adjustment auxiliary tooling 4 is composed of a measuring plane 401, a connecting member 402 and a mounting plane 403 which are fixedly connected in sequence; The mounting plane 403 is connected to the secondary mirror structure 2 ; and the mounting plane 403 is parallel to the measuring plane 401 .

[0026] Example 2 Based on Example 1, this example discloses a method for calibrating a secondary mirror gasket of a high-resolution space camera, comprising the following steps: Step 1: When the secondary mirror gasket 3 to be repaired is assembled on the high-resolution space camera 1, a first reference point test result of the measuring plane 401 of the secondary mirror assembly auxiliary tooling 4 connected to the secondary mirror structure 2 is obtained; Step 2: When the high-resolution space camera 1 is in an optimal state of wave aberration, a second reference point test result of the measuring plane 401 of the secondary mirror assembly auxiliary tooling 4 connected to the secondary mirror structure 2 is obtained; Step 3: Compare the first benchmark point test result and the second benchmark point test result to calculate the grinding thickness of the secondary mirror gasket; Step 4: Correct the secondary mirror gasket 3 to be repaired based on the obtained grinding thickness of the secondary mirror gasket.

[0027] Specifically: Step 1 specifically includes: S1. Build the primary and secondary mirror adjustment workbench, and ensure that the measurement axis of the four-dimensional dynamic interferometer 9 on the primary and secondary mirror adjustment workbench is parallel to the optical axis of the high-resolution space camera 1, and the measurement axis of the four-dimensional dynamic interferometer 9 coincides with the measurement point of the measurement plane 401; S2. The secondary mirror gasket 3 to be repaired is fixedly connected to the high-resolution space camera 1, specifically by screws; S3. The secondary mirror assembly auxiliary tooling 4 is fixedly connected to the secondary mirror structure 2 of the high-resolution space camera 1, specifically by screws; S4. Use the micrometer 6 to measure the initial position of each measuring point on the measuring plane 401, and record the first reference point test result and then return to zero.

[0028] Step 2 specifically includes: S5. The secondary mirror structure 2 of the high-resolution space camera 1 is disassembled, and the secondary mirror structure 2 is fixedly connected to the five-dimensional adjustment frame 5 by the secondary mirror mounting auxiliary tooling 4, specifically by screws; S6. A camera wave aberration test optical path is constructed based on a four-dimensional dynamic interferometer 9 and a plane mirror 8, and the spatial position of the secondary mirror structure 2 is adjusted by a five-dimensional adjustment frame 5 so that the optical image plane of the high-resolution space camera 1 reaches the optimal wave aberration state; S7. Use the micrometer 6 to measure the displacement of each measuring point on the measuring plane 401 after installation and adjustment; S8. According to the displacement of each measuring point, the position relationship change of the measuring plane 401 is calculated as the second reference point test result.

[0029] Step three specifically includes: S9. Compare and calculate the first reference point test results and the second reference point test results to obtain the displacement of each measuring point and the measurement plane deflection angle in the change of the positional relationship of the measurement plane 401; S10. The grinding thickness of the secondary mirror gasket adapted to the secondary mirror mounting surface is calculated using the length L of the left and right end surfaces of the adjustment fixture, the displacement of each measuring point, and the measurement plane deflection angle in the change of the position relationship of the measurement plane 401.

[0030] The measuring points on the measuring plane 401 are all edge measuring points, and there are three of them, which are adapted to the number and installation position of the micrometer 6. Furthermore, the installation direction of the micrometer 6 is adjusted so that the relative error of the three micrometers 6 when measuring the same plane is less than 1 μm; and by ensuring that the measuring directions of the three micrometers 6 are highly parallel, the measurement accuracy of the three micrometers 6 is better than 1 μm.

[0031] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A high-resolution space camera secondary mirror gasket calibration system, characterized in that: include: A high-resolution space camera (1), a secondary mirror gasket to be repaired (3), a secondary mirror assembly auxiliary tool (4), a five-dimensional adjustment frame (5), a micrometer assembly, a plane mirror (8), and a four-dimensional dynamic interferometer (9); The secondary mirror gasket (3) to be repaired is detachably connected to the high-resolution space camera (1); One end of the secondary mirror assembly auxiliary tooling (4) is detachably connected to the secondary mirror structure (2) in the high-resolution space camera (1), and the other end is a measuring plane (401) that fits the micrometer component; The secondary mirror assembly and adjustment auxiliary tooling (4) is detachably connected to the five-dimensional adjustment frame (5); The four-dimensional dynamic interferometer (9) and the plane mirror (8) cooperate in the optical path to provide a reference datum for the calibration system.

2. The high-resolution space camera secondary mirror gasket calibration system according to claim 1, characterized in that: The micrometer assembly is composed of three micrometers (6) and a micrometer base (7); The three dial gauges (6) are all mounted on the dial gauge seat (7).

3. The high-resolution space camera secondary mirror gasket calibration system according to claim 2, characterized in that: The measuring directions of the three micrometers (6) are highly parallel.

4. A method for calibrating the secondary mirror gasket of a high-resolution space camera, characterized in that: Based on the high-resolution space camera secondary mirror gasket calibration system according to claim 3, the calibration method comprises the following steps: Step 1: When the secondary mirror gasket (3) to be repaired is assembled on the high-resolution space camera (1), a first reference point test result of a measurement plane (401) of a secondary mirror assembly auxiliary tooling (4) connected to the secondary mirror structure (2) is obtained; Step 2: When the high-resolution space camera (1) is in an optimal state of wave aberration, a second reference point test result of a measurement plane (401) of a secondary mirror assembly auxiliary tooling (4) connected to the secondary mirror structure (2) is obtained; Step 3: Compare the first benchmark point test result and the second benchmark point test result to calculate the grinding thickness of the secondary mirror gasket; Step 4: Correct the secondary mirror gasket to be repaired (3) based on the obtained grinding thickness of the secondary mirror gasket.

5. The high-resolution space camera secondary mirror gasket calibration method according to claim 4, characterized in that: Step 1 specifically includes: S1. Build a primary and secondary mirror adjustment workbench, and ensure that the measurement axis of the four-dimensional dynamic interferometer (9) on the primary and secondary mirror adjustment workbench is parallel to the optical axis of the high-resolution space camera (1), and the measurement axis of the four-dimensional dynamic interferometer (9) coincides with the measurement point of the measurement plane (401); S2. The secondary mirror gasket (3) to be repaired is fixedly connected to the high-resolution space camera (1); S3. The secondary mirror assembly auxiliary tooling (4) is fixedly connected to the secondary mirror structure (2) of the high-resolution space camera (1); S4. Use the micrometer (6) to measure the initial position of each measuring point on the measuring plane (401), record the first reference point test result and then return to zero.

6. The high-resolution space camera secondary mirror gasket calibration method according to claim 4, characterized in that: Step 2 specifically includes: S5. The secondary mirror structure (2) in the high-resolution space camera (1) is disassembled, and the secondary mirror structure (2) is fixedly connected to the five-dimensional adjustment frame (5) through the secondary mirror adjustment auxiliary tooling (4); S6. A camera wave aberration test optical path is constructed based on a four-dimensional dynamic interferometer (9) and a plane mirror (8), and the spatial position of the secondary mirror structure (2) is adjusted through a five-dimensional adjustment frame (5) so that the image plane of the high-resolution space camera optics (1) reaches an optimal wave aberration state; S7. Use a micrometer (6) to measure the displacement of each measuring point on the measuring plane (401) after installation and adjustment; S8. Based on the displacement of each measuring point, the positional relationship change of the measuring plane (401) is calculated as the second reference point test result.

7. The high-resolution space camera secondary mirror gasket calibration method according to claim 4, characterized in that: Step three specifically includes: S9. Compare and calculate the first reference point test result and the second reference point test result to obtain the displacement of each measuring point and the deflection angle of the measuring plane in the change of the position relationship of the measuring plane (401); S10. The grinding thickness of the secondary mirror gasket adapted to the secondary mirror mounting surface is calculated by using the length L of the left and right end surfaces of the adjustment tool, the displacement of each measuring point and the measurement plane deflection angle in the change of the position relationship of the measurement plane (401).

8. The method for calibrating the secondary mirror gasket of a high-resolution space camera according to claim 4, characterized in that: The measuring points on the measuring plane (401) are all edge measuring points, and there are three of them in total, which are compatible with the number and installation position of the micrometer (6).

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