Device and method for testing optical axis offset of optical imager under impact condition

Abstract

The invention discloses equipment and a method for testing optical axis offset of an optical imager under an impact condition, and the equipment comprises a high-rigidity collimator which comprises a high-rigidity optical system, a high-rigidity target and a light source and is used for simulating an optical target, and light emitted by an infrared light source penetrates through the high-rigidity target, enters the high-rigidity optical system and emits an image; the tested optical imager is used for receiving an image emitted by the high-rigidity collimator and imaging the image into a light spot; the data acquisition and comprehensive control system is used for acquiring light spots of the detected optical imager and carrying out optical axis offset calculation and analysis; and the movable platform is used for providing an impact spectrum for the high-rigidity collimator and the measured optical imager. The optical system is high in connection rigidity and reliability, high-stability optical target simulation under the impact condition is achieved, and meanwhile optical imager optical axis offset testing under the impact condition is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of optical testing, and particularly to a device and method for testing the optical axis offset of an optical imager under impact conditions. Background Art

[0002] For an aircraft, an optical imager is a high-precision angle measuring instrument. Since the aircraft needs to continuously correct its attitude and trajectory according to the flight trajectory of a ballistic aircraft, elastic deformation of the optical seeker causes a change in the optical axis direction. Since the optical seeker is a precision guidance component, a deformation at the micron level will cause a deviation of the optical axis of the seeker at the second level, which will reduce the target tracking accuracy or even cause the loss of the target. Seriously, plastic deformation may occur in the optical seeker, resulting in the failure of the optical seeker and directly leading to the failure of the guidance mission. Therefore, it is necessary to measure the optical axis offset of the optical imager under impact conditions before launch. Existing optical axis offset tests all use static test methods, which can only test the change in the optical axis offset before and after impact, and cannot test the optical axis offset of the optical imager under dynamic conditions. Summary of the Invention

[0003] Based on the above, the object of the present invention is to provide a device and method for testing the optical axis offset of an optical imager under impact conditions, which can output a highly stable optical target under impact conditions and can cooperate with an optical axis offset test algorithm to specifically test the optical axis offset of the optical imager to be measured.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A device for testing the optical axis offset of an optical imager under impact conditions, comprising:

[0006] A high-rigidity collimator, including a high-rigidity optical system, a high-rigidity target, and a light source, for simulating an optical target. The light emitted by the infrared light source passes through the high-rigidity target and enters the high-rigidity optical system to emit an image;

[0007] The optical imager to be measured, which is used to receive the image emitted by the high-rigidity collimator and image it into a light spot;

[0008] A data acquisition and integrated control system, which is used to collect the light spot of the optical imager to be measured and perform calculation and analysis of the optical axis offset;

[0009] A moving platform, which is used to provide an impact spectrum for the high-rigidity collimator and the optical imager to be measured.

[0010] As a preferred solution of a device for testing the optical axis offset of an optical imager under impact conditions, the light source is arranged coaxially with the optical path in front of the high-rigidity target;

[0011] The high-rigidity optical system includes a primary mirror and a secondary mirror arranged coaxially along the optical path in sequence, and the focal plane is located on the incident light side of the primary mirror.

[0012] A high-rigidity target, which is installed at the focal plane of the high-rigidity optical system.

[0013] As a preferred solution of a test device for the optical axis offset of an optical imager under impact conditions, the high-rigidity optical system further includes a frame, a primary mirror backplane, and a plurality of spokes. The primary mirror is fixedly connected to the primary mirror backplane, the secondary mirror is fixedly connected to the frame through the spokes, the high-rigidity target is fixedly connected to the primary mirror backplane, holes are provided at the centers of the primary mirror backplane and the primary mirror, and the primary mirror backplane, the primary mirror, and the secondary mirror are arranged coaxially along the optical path in sequence.

[0014] As a preferred solution of a test device for the optical axis offset of an optical imager under impact conditions, the optical system further includes an adjusting pad, which is arranged at the hole of the primary mirror backplane and abuts against the primary mirror backplane and the high-rigidity target.

[0015] As a preferred solution of a test device for the optical axis offset of an optical imager under impact conditions, the optical system further includes a secondary mirror pad, which abuts against the spoke and the secondary mirror.

[0016] As a preferred solution of a test device for the optical axis offset of an optical imager under impact conditions, a through hole is provided at the center of the high-rigidity target, and the shape of the through hole is any one of a circle and a rectangle.

[0017] As a preferred solution of a test device for the optical axis offset of an optical imager under impact conditions, the number of the spokes is at least 12, and the width of each spoke is ≥5 mm.

[0018] As a preferred solution of a test device for the optical axis offset of an optical imager under impact conditions, the specific stiffness of the materials used for the high-rigidity target and the high-rigidity optical system is ≥60×10^6 m.

[0019] A method for testing the optical axis offset of an optical imager under impact conditions, based on the test device for the optical axis offset of an optical imager under impact conditions, includes the following steps:

[0020] Place the high-rigidity collimator and the optical imager under test facing each other on the moving platform, and the high-rigidity collimator emits an image to the optical imager under test:

[0021] The optical imager under test receives and stores the image emitted by the high-rigidity collimator in real time and forms a light spot for imaging;

[0022] The data acquisition and integrated control system acquires the spot stored in the optical imager under test, and performs interpretation according to the centroid algorithm to obtain the optical axis offset of the optical imager under test under impact conditions.

[0023] As a preferred solution of the optical axis offset test method for the optical imager under impact conditions, the centroid algorithm is specifically:

[0024]

[0025]

[0026] Among them, the centroid of X is the centroid position of the spot in the X direction in the entire image, x is the abscissa of the target pixel, B is the gray level of the target pixel point, the centroid of Y is the centroid position of the spot in the Y direction in the entire image, and y is the ordinate of the target pixel.

[0027] The beneficial effects of the present invention are:

[0028] In the present invention, the optical system includes a primary mirror, a secondary mirror, a frame, a primary mirror backplane, and a plurality of spokes. The primary mirror is fixedly connected to the primary mirror backplane and the frame, the secondary mirror is fixedly connected to the frame through the spokes, and the target is fixedly connected to the primary mirror backplane, with relatively high connection stiffness and reliability, realizing a high-stability optical target simulation under impact conditions; by placing the optical axis offset test device and the optical imager under test relatively on the moving platform, the optical imager under test receives and stores the image sent by the optical axis offset test device in real time, the data acquisition and integrated control system acquires the image stored by the optical imager under test, and calculates the optical axis offset according to the centroid algorithm, realizing the optical axis offset test of the optical imager under impact conditions. Description of the Drawings

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments of the present invention. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the content of the embodiments of the present invention and these drawings.

[0030] Figure 1 is a schematic structural diagram of the optical system provided by the embodiment of the present invention;

[0031] Figure 2 is Figure 1 the A-direction structural diagram of

[0032] Figure 3 is the shock spectrum diagram provided by the embodiment of the present invention;

[0033] Figure 4It is a schematic diagram of the test method provided by an embodiment of the present invention.

[0034] In the figure: 1, primary mirror; 2, secondary mirror; 3, frame; 4, backplane of primary mirror; 5, high-rigidity target; 6, light source; 7, secondary mirror pad; 8, adjustment pad; 9, spoke. Specific Embodiments

[0035] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only for explaining the present invention, rather than limiting the present invention. Additionally, it should be noted that for the sake of description, only the parts related to the present invention are shown in the drawings, rather than all the structures.

[0036] In the description of the present invention, unless otherwise clearly specified and defined, the terms "connected", "connected to", and "fixed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] In the present invention, unless otherwise clearly specified and defined, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features between them. Moreover, the first feature being "above", "over", and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "under", and "beneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or simply means that the horizontal height of the first feature is lower than that of the second feature.

[0038] In the description of this embodiment, the orientation or positional relationship terms such as "above", "below", "left", and "right" are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of description and simplifying the operation, 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 a limitation to the present invention. In the description of the present invention, unless otherwise stated, the meaning of "a plurality of" is two or more. In addition, the terms "first" and "second" are only used for distinction in description and do not have special meanings.

[0039] Since the aircraft needs to continuously correct its attitude and trajectory according to the flight trajectory of the ballistic missile, the optical seeker generates elastic deformation, resulting in a change in the optical axis direction of the optical imager. For example, in order to improve the orbit-changing response speed of the aircraft, new aircraft have abandoned the method of changing orbit by using a steering gear and instead adopted the method of rapid ignition of multiple lateral engines for orbit-changing. Therefore, the lateral engines of the aircraft need to be ignited frequently, especially when approaching the target, the engine ignition is extremely frequent. When the lateral engine ignites, a large lateral thrust will be generated, and this thrust will act on the aircraft and be transmitted to various components on the aircraft. Among them, the optical seeker will also receive the thrust transmitted from the missile body. When the lateral thrust is large, the optical seeker generates elastic deformation, resulting in a change in the optical axis direction of the optical imager. Since the optical seeker is a precision guidance component, a deformation of the micron level will cause a deviation of the optical axis of the seeker at the second level. This embodiment provides a method for measuring the optical axis offset of the optical imager under impact conditions before launch.

[0040] As Figures 1 to 2 shown, this embodiment provides an optical axis offset test device for an optical imager under impact conditions, including a high-rigidity collimator. The high-rigidity collimator includes a high-rigidity optical system, a high-rigidity target, and a light source, which is used to simulate an optical target. The light emitted by the infrared light source passes through the hole of the high-rigidity target and enters the high-rigidity optical system to emit an image; the optical imager to be measured is used to receive the image emitted by the high-rigidity collimator and image it into a light spot; the data acquisition and integrated control system is used to collect the light spot of the optical imager to be measured and perform calculation and analysis of the optical axis offset; the moving platform is used to provide an impact spectrum for the high-rigidity collimator and the optical imager to be measured, and the impact spectrum pattern is as Figure 3 shown. The light source can be an infrared light source or a visible light source. When the imager to be measured is in the infrared band, an infrared light source is selected to illuminate the target, and when the imager to be measured is in the visible light band, a visible light source is selected to illuminate the target.

[0041] Specifically, the light source is arranged coaxially with the optical axis along the optical path in front of the high-rigidity target; the high-rigidity optical system includes a primary mirror and a secondary mirror arranged coaxially along the optical path in sequence, and the focal plane is located on the incident light side of the primary mirror; the high-rigidity target is installed at the focal plane of the high-rigidity optical system, and a through hole is provided at the center of the high-rigidity target, and the shape of the through hole is any one of a circle and a rectangle.

[0042] More specifically, the high-rigidity optical system further includes a frame, a primary mirror backplane, and multiple spokes. The frame serves both as a support structure connecting the primary mirror and the secondary mirror and as a connection interface between the high-rigidity collimator and the impact test bench. The primary mirror is connected to the primary mirror backplane by screws, and the primary mirror backplane is connected to the frame by screws to ensure good connection rigidity and reliability. The high-rigidity target is connected to the primary mirror backplane by screws, and the secondary mirror is connected by screws. The secondary mirror is fixedly connected to the frame through spokes. Holes are provided at the centers of the primary mirror backplane and the primary mirror. The primary mirror backplane, the primary mirror, and the secondary mirror are coaxially arranged in sequence along the optical path. Multiple connection holes are provided between the high-rigidity collimator and the moving platform to ensure good installation rigidity. At the same time, the manufacturability of the installation is considered during the design to ensure that there is a certain operating space for the installation screws with respect to the primary mirror and the secondary mirror. The optical system further includes an adjustment pad and a secondary mirror pad. The adjustment pad is arranged at the hole of the primary mirror backplane and abuts against the primary mirror backplane and the high-rigidity target. The secondary mirror pad abuts against the spoke and the secondary mirror, and has good stability under impact. In the embodiment of the present invention, the number of spokes is at least 12, and the width of each spoke is ≥5 mm to ensure good connection rigidity and reliability of the high-rigidity collimator.

[0043] The specific stiffness of the materials used for the high-rigidity target and the high-rigidity optical system is ≥60×10^6 m. The high-rigidity collimator uses an all-metal opto-mechanical system, and its first-order mode needs to be above 2000 Hz. Under impact conditions, the optical axis offset is ≤1″, and the anti-impact performance is strong.

[0044] As Figure 4 shown, a method for testing the optical axis offset of an optical imager under impact conditions includes the following steps:

[0045] Place the high-rigidity collimator and the optical imager under test face to face on the moving platform. The moving platform can provide an impact spectrum with certain characteristic parameters for the optical imager optical axis offset test equipment and the optical imager under test. The waveform diagram of the impact spectrum is as Figure 3 shown. The ordinate is acceleration, the abscissa is impact time, and the unit is millisecond (ms). The rise time of the trapezoidal spectrum is 1 ms, the stable duration is 15 ms, the fall time is 1 ms, and the impact peak acceleration is 5.7 g. The high-rigidity collimator emits a high-rigidity circular image to the optical imager under test:

[0046] The optical imager under test receives and stores the circular image emitted by the high-rigidity collimator in real time and forms a circular light spot;

[0047] The data acquisition and integrated control system collects the light spot stored by the optical imager under test and performs interpretation according to the centroid algorithm. The centroid algorithm is specifically as follows:

[0048]

[0049]

[0050] The X centroid is the centroid position of the light spot in the X direction in the entire image, x is the abscissa of the target pixel, B is the gray level of the target pixel point, the Y centroid is the centroid position of the light spot in the Y direction in the entire image, y is the ordinate of the target pixel, that is, the optical axis offset of the optical imager under test under impact conditions is obtained, and the test of the optical axis offset of the optical imager under impact conditions is realized. The centroid positions of the light spot in the X direction and the Y direction in the entire image are the optical axis offsets of the optical imager under test under impact.

[0051] Note that the above is only the preferred embodiment of the present invention and the technical principles applied. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described here. Various obvious changes, re-adjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the concept of the present invention, more other equivalent embodiments can be included, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. An optical imager optical axis offset measurement device under impact conditions, characterized in that Comprising: A high-rigidity collimator, including a high-rigidity optical system, a high-rigidity target, and a light source, for simulating an optical target. The light emitted by the infrared light source passes through the high-rigidity target and enters the high-rigidity optical system to emit an image. The optical imager under test, which is used to receive the image emitted by the high-rigidity collimator and image it into a light spot. The data acquisition and integrated control system, which is used to collect the light spot of the optical imager under test and perform calculation and analysis on the optical axis offset. A moving platform, which is used to provide an impact spectrum for the high-rigidity collimator and the optical imager under test.

2. The optical imager optical axis offset measurement device under impact conditions according to claim 1, characterized in that, The light source is arranged coaxially with the optical path in front of the high-rigidity target. The high-rigidity optical system includes a primary mirror and a secondary mirror arranged coaxially along the optical path in sequence, and the focal plane is located on the incident light side of the primary mirror. The high-rigidity target is installed at the focal plane of the high-rigidity optical system.

3. The optical axis offset measurement device for an optical imager under impact conditions according to claim 2, characterized in that, The high-rigidity optical system further includes a frame, a primary mirror backplane, and a plurality of spokes. The primary mirror is fixedly connected to the primary mirror backplane, the secondary mirror is fixedly connected to the frame through the spokes, the high-rigidity target is fixedly connected to the primary mirror backplane, and holes are opened at the centers of the primary mirror backplane and the primary mirror. The primary mirror backplane, the primary mirror, and the secondary mirror are arranged coaxially along the optical path in sequence.

4. The optical imager optical axis offset measurement device under impact conditions according to claim 2, characterized in that, The optical system further includes an adjustment pad, which is arranged at the hole of the primary mirror backplane and abuts against the primary mirror backplane and the high-rigidity target.

5. The optical axis offset measurement device for an optical imager under impact conditions according to claim 2, characterized in that, The optical system further includes a secondary mirror pad, which abuts against the spoke and the secondary mirror.

6. The optical axis offset measurement device for an optical imager under impact conditions according to claim 2, characterized in that, A through hole is provided at the center of the high-rigidity target, and the shape of the through hole is any one of a circle and a rectangle.

7. The optical imager optical axis offset measurement device under impact conditions according to claim 3, characterized in that, The number of the spokes is at least 12, and the width of each spoke is ≥5 mm.

8. The optical axis offset measurement device for an optical imager under impact conditions according to claim 1, characterized in that, The specific stiffness of the materials used for the high-rigidity target and the high-rigidity optical system is ≥60×10^6 m.

9. A method for testing the optical axis offset of an optical imager under impact conditions, based on the test equipment for the optical axis offset of an optical imager under impact conditions described in any one of claims 1-8, characterized in that, Including the following steps: Place the high-rigidity collimator and the optical imager under test face to face on the moving platform, and the high-rigidity collimator emits an image to the optical imager under test: The optical imager under test receives and stores the image emitted by the high-rigidity collimator in real time and images it into a light spot. The data acquisition and integrated control system collects the light spot stored by the optical imager under test and performs interpretation according to the centroid algorithm to obtain the optical axis offset of the optical imager under test under impact conditions.

10. The optical imager optical axis offset measurement device under impact conditions according to claim 9, characterized in that, The specific centroid algorithm is: Wherein, X_centroid is the centroid position of the light spot in the X direction in the entire image, x is the abscissa of the target pixel, B is the gray level of the target pixel point, Y_centroid is the centroid position of the light spot in the Y direction in the entire image, and y is the ordinate of the target pixel.

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