In-orbit detection system and method for coplanarity of space film spliced multi-sub-mirror system

Abstract

The application provides a spaceflight film spliced multi-sub-mirror system coplanarity on-orbit detection system and method, which comprises the following parts: a measuring frame, which is responsible for fixing all sensors; the sensors, which are arranged below the measuring frame and are respectively aligned with the top surfaces of the central mirror and the sub-mirror covered by the measuring frame; a rotating mechanism, which is responsible for driving the whole measuring frame to rotate and realizing detection of the heights of all sub-mirrors and the central mirror of the whole optical system; a cable, which is a bundled cable and is wired along the measuring frame and connected to a controller; the controller, which controls the rotation of the rotating mechanism and reads the data of all sensors and processes the obtained data; a calibration system, which corrects and compensates the deformation of the measuring frame and the installation error of the sensors; and a base, which fixes the platform of the rotating mechanism and provides installation space for the calibration system. The technical scheme of the application can significantly reduce the one-time measurement range and effectively solve the contradiction between large range and high precision.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of spaceflight, in particular to a system and method for detecting the coplanarity of a spaceflight thin film spliced multi-mirror system in orbit. BACKGROUND

[0002] With the continuous development of space in-orbit assembly technology, more and more large in-orbit assembly optical systems have been practically applied. These large assembly optical systems are often composed of multiple mirrors, and the larger the size of the optical system, the greater the number of mirrors that make up the system, and the speed of the system increases (as shown in the figure). Therefore, how to ensure that these numerous mirrors can be on the plane or curved surface required by the optical design has become the key to the success of the in-orbit spliced optical system. For this reason, in-orbit adjustment will be the only option and technical path, and how to detect the coplanarity of all mirrors in orbit becomes a core key link. Figure 1

[0003] After searching, patent document CN103759922A discloses a space remote sensor two-dimensional pointing mirror pointing accuracy measurement method, establishes a mathematical model of the spatial motion trajectory of the mirror surface normal when the two-dimensional pointing mirror rotates around the roll axis and the pitch axis; uses a theodolite to measure the spatial trajectory of the mirror surface normal; combines the mathematical model and the measurement data, and uses the characteristic root least squares method to process the data; and uses the data processing result as a basis to feedback the two-dimensional pointing mirror controller.

[0004] Patent document CN10714424A discloses a binocular vision high-precision measurement method based on depth compensation, which belongs to the technical field of computer vision measurement and relates to a binocular vision high-precision measurement method based on depth compensation. The method first calibrates the initial position of two cameras, then adjusts the two-dimensional target and the left and right camera planes, solves the distortion coefficient of the position, and solves the structure parameters between the left and right cameras; then, the planar target is translated towards the left and right camera planes, and the parameters are calibrated; a radial distortion compensation model in the depth direction is established, the measurement accuracy of different depth information is compensated, and high-precision measurement of the binocular camera in the depth direction is realized.

[0005] ​Patent document CN108344360A discloses a laser scanning type global calibration device and method of a visual measurement system, which comprises: fixing and installing two line lasers on a multi-degree-of-freedom turntable, controlling the rotation of the turntable, projecting a laser plane into the field of view of a camera to be calibrated, calibrating the laser plane equation in the camera coordinate system with the aid of a plane feature point target, rotating the turntable multiple times to change the position of the laser plane in the camera field of view, and continuing to calibrate the laser plane. Rotate the turntable to project the laser plane into the field of view of another camera to be calibrated to calibrate the laser plane. Through the rotation data output by the turntable in real time, and the laser plane equations calibrated in the camera coordinate system and the turntable coordinate system, the position parameters between the two cameras to be calibrated, i.e. the rotation matrix and the translation vector, are solved by taking the laser plane as a medium.

[0006] However, it is very difficult to realize the detection of the coplanarity of the plurality of sub-mirrors. The main difficulties are as follows: firstly, the heights of the sub-mirrors are inevitably uneven, so that the coplanarity of the sub-mirrors of the entire optical system belongs to a large-size, multi-target, three-dimensional position and attitude measurement problem, which is extremely difficult; secondly, the rigidity, stability and stability of the detection system will inevitably directly affect the measurement precision of the final coplanarity, which is also the biggest obstacle; thirdly, how to calibrate and calibrate the detection system to realize the traceability of precision is a guarantee of the in-orbit detection precision and reliability, and is also an unavoidable problem; fourthly, the detection system has difficulty in guaranteeing the detection precision requirement due to the large amplitude temperature difference change in the in-orbit detection.

[0007] The above problems become the key to realize the in-orbit detection of the optical system, and are one of the technical problems that cannot be solved in the industry at present.

[0008] Patent document CN109813240A (application number: CN201910160359.8) discloses a coplanarity detection device of an electrical connector, which comprises: a reference platform, a positioning adjuster for moving the electrical connector to a detection hole is arranged on the reference platform; a two-dimensional laser displacement sensor, a fan-shaped laser plane emitted by a laser emitting end can be reflected to a laser receiving end by the electrical connector located at the detection hole; a controller, which analyzes the position information of the lowest part of the soldering foot in the to-be-measured region of the electrical connector and the position information of the bottom surface of the base part, calculates the height difference between the lowest part of the soldering foot and the bottom surface of the base part, and judges whether the height difference exceeds the coplanarity threshold; a display, which is used to display the profile line image converted from the profile line information and the detection result of whether the coplanarity of the electrical connector is qualified. However, the invention is not used in the field of aerospace. SUMMARY

[0009] Aiming at the defects in the prior art, the purpose of the present application is to provide a space film splicing type multi-sub-mirror system coplanarity on-orbit detection system and method.

[0010] The space film splicing type multi-sub-mirror system coplanarity on-orbit detection system provided by the present application comprises:

[0011] The measuring frame is located at a preset distance above the sub-mirror, can cover a central mirror and a preset number of sub-mirrors, is responsible for fixing all the sensors, and keeps the positions of all the sensors accurate and stable.

[0012] The sensors are a plurality of sensors arranged below the measuring frame, are respectively aligned with the top surfaces of the central mirror and the sub-mirrors covered by the measuring frame.

[0013] The rotating mechanism is a central rotating system, is connected with the measuring frame at the top, is responsible for driving the whole measuring frame to rotate, and realizes detection of the heights of all the sub-mirrors and the central mirror of the whole optical system.

[0014] The cable is a bundled cable, is a bundle of cables for the sensors on the measuring frame and the rotating mechanism, is wired along the measuring frame, and is connected to the controller.

[0015] The controller controls the rotation of the rotating mechanism, reads the data of all the sensors, processes the obtained data, and obtains the coplanarity detection result.

[0016] The calibration system is arranged beside the detection system, corrects and compensates for the deformation of the measuring frame and the installation error of the sensors.

[0017] The base is a platform for fixing the rotating mechanism, and provides an installation space for the calibration system.

[0018] Preferably, the measuring frame is a light-weight high-rigidity structure.

[0019] Preferably, the sensors are laser displacement sensors, and the laser triangulation principle is adopted to realize non-contact measurement of the top surface height of the sub-mirror.

[0020] Preferably, the number of the sensors should ensure that at least three sensors can work when the central mirror and each sub-mirror are measured.

[0021] Preferably, the rotating mechanism starts to measure after rotating through a certain angle each time, and the angle of rotation ensures that the sensors can measure the top surface height of the next group of sub-mirrors, and the angle is called a division angle.

[0022] The space film splicing type multi-sub-mirror system coplanarity on-orbit detection method provided by the present application adopts the space film splicing type multi-sub-mirror system coplanarity on-orbit detection system, and executes the following steps.

[0023] Step S1: Place the measuring frame on the calibration system, record the measurement values of all sensors, and save as the reference value;

[0024] Step S2: Place the measuring frame on the optical system to be measured, record the measurement values of all sensors, and subtract the reference value saved previously to obtain the measurement deviation value of each sensor;

[0025] Step S3: Average the three sensors corresponding to the center mirror and each sub-mirror respectively to obtain the height value of the center mirror and each sub-mirror;

[0026] Step S4: Subtract the height value of each sub-mirror from the height value of the center mirror to obtain the coplanarity deviation value of the sub-mirror relative to the center mirror;

[0027] Step S5: Under the control of the controller, drive the rotating mechanism to rotate by a preset angle, so that the measuring frame rotates to the next group of sub-mirrors;

[0028] Repeat steps S2 to S5 to complete the measurement of the remaining all sub-mirrors to obtain the coplanarity deviation value of all sub-mirrors relative to the center mirror.

[0029] Preferably, the measuring frame is a light-weight high-rigidity structure;

[0030] Preferably, the sensor is a laser displacement sensor, which realizes non-contact measurement of the height of the top surface of the sub-mirror by using the laser triangulation principle.

[0031] Preferably, the number of sensors should ensure that at least 3 sensors can work when measuring the center mirror and each sub-mirror.

[0032] Preferably, the rotating mechanism starts to measure after rotating by a certain angle, and the angle of rotation ensures that the sensors can measure the top surface height of the next group of sub-mirrors, which is called the indexing angle.

[0033] Compared with the prior art, the present application has the following beneficial effects:

[0034] 1. The technical scheme of the present application can significantly reduce the one-time measurement range, not only ensuring high measurement accuracy, but also considering the coverage of the entire optical system, effectively solving the contradiction between large range and high accuracy;

[0035] 2. The detection system of the technical scheme of the present application always has a center mirror as a reference during rotation, and only needs to focus on the relative height information of a few sub-mirror frames and the center mirror during each measurement, without interfering and affecting each measurement, greatly reducing the rigidity and stability requirements of the mechanical unit of the detection system, and greatly reducing the implementation difficulty;

[0036] 3、The detection system of the technical scheme of the present application can adapt to large amplitude slow temperature change, and meets the actual demand of in-orbit detection. BRIEF DESCRIPTION OF DRAWINGS

[0037] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments, made with reference to the following drawings:

[0038] Figure 1 It is a schematic diagram of a typical in-orbit spliced optical system;

[0039] Figure 2 It is a schematic diagram of the composition of the in-orbit detection system of the present application for the co-planarity of multiple sub-mirrors;

[0040] Figure 3 It is a schematic diagram of the sensor layout of the in-orbit detection system of the present application for the co-planarity of multiple sub-mirrors;

[0041] Figure 4 It is a schematic diagram of the indexing angle of the in-orbit detection system of the present application for the co-planarity of multiple sub-mirrors.

[0042] Wherein, 1 is a measuring frame, 2 is a sensor, 3 is a rotating mechanism, 4 is a cable, 5 is a controller, 6 is a calibration system, 7 is a base, 8 is a sub-mirror, and 9 is a central mirror. DETAILED DESCRIPTION

[0043] The present application will be described in detail below with specific embodiments. The following embodiments will help those skilled in the art to further understand the present application, but do not limit the present application in any form. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present application. These are within the scope of protection of the present application.

[0044] Example 1:

[0045] The present application discloses an in-orbit detection system for the co-planarity of a spliced multiple sub-mirror of a spaceflight thin film, which is composed of a measuring frame, a sensor, a rotating mechanism, a cable, a controller and a calibration system. The measuring frame covers a central mirror and several sub-mirrors, and at least three laser displacement sensors are used for measuring each sub-mirror. The rotating mechanism measures the relative co-planarity information of the sub-mirror and the central mirror each time, and rotates by a certain angle to ensure the measurement of the top surface height of the next group of sub-mirrors.

[0046] The present application proposes an in-orbit detection method of "local measurement + global rotation" to overcome the shortcomings and defects of the existing detection method of in-orbit spliced optical system. The detection system measures the co-planarity of several local sub-mirrors each time for rapid measurement, and then the detection system rotates and moves to gradually cover the entire optical system, so as to realize the co-planarity detection of all sub-mirrors. The present application is realized by the following technical scheme:

[0047] A multi-sub-mirror co-planarity on-orbit detection system, as shown in Figures 1-4 characterized in that:

[0048] The detection system is composed of a measuring frame 1, sensors 2, a rotating mechanism 3, a cable 4, a controller 5 and a calibration system 6, wherein:

[0049] The measuring frame 1 is a lightweight and high-rigidity structure, located at a distance above the sub-mirror 8, can cover a central mirror 9 and several sub-mirrors 8, and is responsible for fixing all the sensors 2 and keeping the positions of all the sensors 2 accurate and stable;

[0050] The sensors 2 are multiple, arranged below the measuring frame 1, respectively aligned with the top surfaces of the central mirror 9 and the sub-mirrors 8 covered by the measuring frame, to obtain distance information of each point on the top;

[0051] The rotating mechanism 3 is a central rotating system, responsible for driving the entire measuring frame 1 to rotate, to realize detection of the heights of all the sub-mirrors 8 and the central mirror 9 of the entire optical system; the bottom of the rotating mechanism 3 is connected with the base 7, and the top is connected with the measuring frame 1;

[0052] The cable 4 is a bundled cable, responsible for connecting all the sensors 2 and the rotating mechanism 3 to the controller 5; the cable 4 is a combination of the cables of the sensors 2 and the rotating mechanism 3 on the measuring frame 1, and is routed along the measuring frame 1 to the controller 5.

[0053] The controller 5 is a high-performance industrial control computer, with built-in data processing software, which can not only control the rotation of the rotating mechanism 3 and read the data of all the sensors 2, but also process the obtained data to finally obtain the co-planarity detection results;

[0054] The calibration system 6 is arranged beside the detection system, responsible for calibrating the entire detection system to correct and compensate for the deformation of the measuring frame 1 and the installation error of the sensors 2.

[0055] The measuring system includes two parts of the detection system and the calibration system; the calibration system 6 is not needed when the detection system is normally working, and is used only when the precision of the detection system needs to be calibrated. Therefore, the calibration system 6 is placed beside the detection system when not in use, and is placed on the base 7 when in use, and is taken off from the base 7 after calibration.

[0056] The base 7 is a platform for fixing the rotating mechanism 3, and provides installation space for the calibration system 6;

[0057] The sensors 2 are laser displacement sensors, which realize non-contact high-precision measurement of the height of the top surface of the sub-mirror by using the laser triangulation principle.

[0058] The number of sensors 2 should ensure that at least 3 sensors can work when the center mirror 9 and each sub-mirror 8 is measured, so as to accurately obtain the height information of the mirror.

[0059] The rotation mechanism 3 starts to measure after rotating through a certain angle, and the angle of rotation can ensure that the sensors 2 can measure the top surface height of the next group of sub-mirrors 8, which can be called the index angle.

[0060] A processing method of the multi-sub-mirror coplanarity on-orbit detection system, characterized in that the processing steps are as follows:

[0061] (1) Place the measuring frame 1 on the calibration system 6, and after stabilization, record the measurement values of all sensors 2 and save them as reference values;

[0062] (2) Place the measuring frame 1 on the measured optical system, and after stabilization, record the measurement values of all sensors 2, and subtract the reference values saved before, that is, the measurement deviation values of each sensor 2 can be obtained;

[0063] (3) Average processing is performed on the three sensors 2 corresponding to the center mirror 9 and each sub-mirror 8, respectively, and the height values of the center mirror 9 and each sub-mirror 8 can be obtained;

[0064] (4) Subtract the height value of each sub-mirror 8 from the height value of the center mirror 9, and the coplanarity deviation value of the sub-mirror 8 relative to the center mirror 9 can be obtained;

[0065] (5) Under the control of the controller 5, drive the rotation mechanism 3 to rotate through a certain angle, generally equal to the index angle, so that the measuring frame 1 rotates to the next group of sub-mirrors;

[0066] (6) Repeat steps (2)-(5) above to complete the measurement of the remaining all sub-mirrors 8, and obtain the coplanarity deviation values of all sub-mirrors 8 relative to the center mirror 9;

[0067] Example 2:

[0068] Embodiment 2 is a preferred example of Embodiment 1, which more specifically illustrates the present application.

[0069] The present application is realized by the following technical solutions:

[0070] The special feature of the multi-sub-mirror coplanarity on-orbit detection system of the present application is that the detection system is composed of a measuring frame 1, sensors 2, a rotation mechanism 3, a cable 4, a controller 5 and a calibration system 6, as shown in Figure 2 , wherein:

[0071] The measuring frame 1 is a light-weight high-rigidity structure, which can be made of aluminum alloy or carbon fiber material for example; the measuring frame 1 is located above the sub-mirror 8 at a distance, which is generally determined by the working distance of the sensor 2 and the installation height; the measuring frame 1 can cover a central mirror 9 and several sub-mirrors 7, for example Figure 2 The measuring frame 1 can cover a central mirror and two adjacent sub-mirrors; the measuring frame 1 is responsible for fixing all the sensors 2 and keeping the positions of all the sensors 2 accurate and stable;

[0072] The sensor 2 is provided in plurality and arranged below the measuring frame 1, and respectively aligned with the top surfaces of the central mirror 9 and the sub-mirror 7 covered by the measuring frame 1 to obtain the distance information of each point on the top; for example Figure 2 In the embodiment shown in FIG. 1, there are 9 sensors 2 in total, of which 3 sensors 2 are aligned with the central mirror, and the remaining 6 sensors 2 are respectively aligned with the two adjacent sub-mirrors;

[0073] The rotating mechanism 3 is a central rotating system, which is responsible for driving the entire measuring frame 1 to rotate to realize the detection of the heights of all the sub-mirrors 7 and the central mirror 9 of the entire optical system;

[0074] The cable 4 is a bundled cable, which is responsible for connecting all the sensors 2 and the rotating mechanism 3 to the controller 5; for example Figure 2 In the embodiment shown in FIG. 1, the cable includes 9 sensor cables and one rotating mechanism control cable;

[0075] The controller 5 is a high-performance industrial control computer, which is provided with data processing software, and can not only control the rotation of the rotating mechanism 3 and read the data of all the sensors 2, but also process the obtained data to finally obtain the coplanarity detection result;

[0076] The calibration system 6 is arranged beside the detection system, which is responsible for calibrating the entire detection system to correct and compensate for the deformation of the measuring frame 1 and the installation error of the sensor 2.

[0077] The working process of the multi-sub-mirror coplanarity on-orbit detection system of the present application is as follows: first, the measuring frame 1 is placed on the calibration system 6 to calibrate all the sensors 2; then the measuring frame 1 is placed on the rotating mechanism 3, and the readings of all the sensors 2 are obtained under the unified control of the controller 5; next, the controller 5 controls the rotating mechanism 3 to rotate and drive the measuring frame 1 to rotate, and then the other sub-mirrors 7 are measured in turn, so as to realize the coplanarity measurement of all the sub-mirrors 7.

[0078] The multi-sub-mirror coplanarity on-orbit detection system of the present application is special in that the sensor 2 is a laser displacement sensor, which realizes the absolute measurement of the target distance by using the laser triangulation principle, and can realize the non-contact high-precision measurement of the height of the top surface of the sub-mirror 7.

[0079] The speciality of the multi-sub-mirror co-planarity on-orbit detection system of the present application is that the number of the sensors 2 should ensure that at least three sensors 2 can work when the center mirror and each sub-mirror 7 are measured, so as to accurately obtain the height information of the mirror, as shown in Figure 3 .

[0080] The speciality of the multi-sub-mirror co-planarity on-orbit detection system of the present application is that the rotation mechanism 3 starts to measure after rotating through a certain angle each time, and the angle of rotation can ensure that the sensors 2 can measure the top surface height of the next group of sub-mirrors 7, which can be called the indexing angle; as shown in Figure 3 , the optical system has a total of 8 sub-mirrors, and they are uniformly distributed, so the indexing angle is 45°.

[0081] The present application proposes a processing method based on the above multi-sub-mirror co-planarity on-orbit detection system, and the specific processing process is as follows:

[0082] (1) Place the measuring frame 1 on the calibration system 6, and after stabilization, record the measurement values of all sensors 2 and save them as reference values; for example, as shown in Figure 2 , the measurement values of the 9 sensors 2 are Li (i=1, 2, …9), and the saved reference values L0i (i=1, 2, …9) are saved;

[0083] (2) Place the measuring frame 1 on the measured optical system, and after stabilization, record the measurement values of all sensors 2 and subtract them from the previously saved reference values, that is, the measurement deviation values of each sensor 2 can be obtained; for example, as shown in Figure 2 , the measurement deviation values of each sensor 2 are: ΔLi = Li - L0i (i=1, 2, …9);

[0084] (3) The measurement deviation values of the three sensors 2 corresponding to the center mirror 9 and each sub-mirror 7 are averaged, respectively, and the height values of the center mirror 9 and each sub-mirror 7 can be obtained; for example, as shown in Figure 2 , the height value of the center mirror 9 is: HC = (ΔL1 + ΔL2 + ΔL3) / 3, the height value of the sub-mirror 7-1 is: H1 = (ΔL4 + ΔL5 + ΔL6) / 3, and the height value of the sub-mirror 7-2 is: H2 = (ΔL7 + ΔL8 + ΔL9) / 3;

[0085] (4) The height value of each sub-mirror 7 is subtracted from the height value of the center mirror 9, and the co-planarity deviation value of the sub-mirror 7 relative to the center mirror 9 can be obtained; for example, as shown in Figure 2 , the co-planarity deviation value of the sub-mirror 7-1 is: P1 = H1 - HC, and the height value of the sub-mirror 7-2 is: P2 = H2 - HC;

[0086] (5) Under the control of the controller 5, the rotary mechanism 3 is driven to rotate by an angle, generally equal to the index angle, so that the measuring frame 1 is aligned with the next group of sub-mirrors; and Figure 2 For example, if the index angle is 45°, the measuring frame 1 is transitioned from measuring sub-mirrors 7-1 and 7-2 to measuring sub-mirrors 7-2 and 7-3;

[0087] (6) Repeat the above steps (2) to (5) to complete the measurement of all remaining sub-mirrors 7 to obtain the coplanarity deviation values of all sub-mirrors 7 relative to the center mirror 9.

[0088] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0089] Those skilled in the art know that in addition to implementing the system, device and each module thereof provided by the present application in a pure computer readable program code manner, the same program can also be implemented in the form of logic gates, switches, application specific integrated circuits, programmable logic controllers and embedded microcontrollers by logically programming the method steps. Therefore, the system, device and each module thereof provided by the present application can be considered as a hardware component, and the modules included therein for implementing various programs can also be considered as structures within the hardware component; the modules for implementing various functions can also be considered as both software programs for implementing methods and structures within hardware components.

[0090] The specific embodiments of the present application have been described above. It should be understood that the present application is not limited to the specific embodiments described above, and various changes or modifications can be made by those skilled in the art within the scope of the claims, which do not affect the essential content of the present application. The embodiments of the present application and the features in the embodiments can be arbitrarily combined with each other without conflict, provided that the combinations do not conflict.

Claims

1. A system for detecting on-orbit co-planarity of a spaceflight thin-film tiled sub-mirror system, characterized in that, The system comprises: a measuring frame (1) located at a preset distance above the sub-mirror (8), capable of covering a central mirror (9) and a preset number of sub-mirrors (8), responsible for fixing all sensors (2), keeping the position of all sensors (2) accurate and stable; a plurality of sensors (2) disposed below the measuring frame (1), respectively aligned with the top surface of the central mirror (9) and the sub-mirror (8) covered by the measuring frame; a rotating mechanism (3), which is a central rotating system, connected to the top of the measuring frame (1); responsible for driving the entire measuring frame (1) to rotate, realizing the detection of the height of all sub-mirrors (8) and central mirrors (9) of the entire optical system; a cable (4), which is a bundled cable, combines the cables of the measuring frame (1), the sensors (2) and the rotating mechanism (3) into one bundle, and is wired along the measuring frame (1) to the controller (5); a controller (5) that controls the rotation of the rotating mechanism (3) and reads the data of all sensors (2), processes the obtained data to obtain the coplanarity detection result; a calibration system (6) arranged beside the detection system, which corrects and compensates for the deformation of the measuring frame (1) and the installation error of the sensor (2); a base (7) that fixes the platform of the rotating mechanism (3) and provides installation space for the calibration system (6); the sensor (2) is a laser displacement sensor, which realizes non-contact measurement of the height of the top surface of the sub-mirror by using the laser triangulation principle; the rotating mechanism (3) starts measuring after rotating a certain angle each time, and the angle of rotation ensures that the sensor (2) can measure the top surface height of the next group of sub-mirrors (8), which is called the division angle; During the rotation process, there is always a central mirror (9) as a reference, and the relative height information of all sub-mirror frames and the central mirror is measured each time.

2. The on-orbit coplanarity detection system of the space thin film splicing type multi-sub-mirror system according to claim 1, characterized in that: the measuring frame (1) is a light-weight high-rigidity structure.

3. The on-orbit coplanarity detection system of the space thin film splicing type multi-sub-mirror system according to claim 1, characterized in that: the number of sensors (2) should ensure that at least 3 sensors can work when measuring the central mirror (9) and each sub-mirror (8).

4. A method for detecting the coplanarity of a space film spliced multi-sub-mirror system in orbit, characterized in that, The on-orbit coplanarity detection system of the space thin film splicing type multi-sub-mirror system according to claim 1 is executed, including: Step S1: Place the measuring frame (1) on the calibration system (6), record the measurement values of all sensors (2), and save them as reference values; Step S2: Place the measuring frame (1) on the measured optical system, record the measurement values of all sensors (2), and subtract them from the previously saved reference values to obtain the measurement deviation values of each sensor (2); Step S3: Average the multiple sensors (2) corresponding to the central mirror (9) and each sub-mirror (8) respectively to obtain the height values of the central mirror (9) and each sub-mirror (8); Step S4: Subtract the height value of each sub-mirror (8) from the height value of the central mirror (9) to obtain the coplanarity deviation value of the sub-mirror (8) relative to the central mirror (9). Step S5: under the control of the controller (5), the rotary mechanism (3) is driven to rotate a preset angle, so that the measuring frame (1) rotates to the next group of sub-mirrors; Repeat steps S2 to S5 to complete the measurement of all remaining sub-mirrors (8) to obtain the coplanarity deviation values of all sub-mirrors (8) relative to the center mirror (9).

5. The coplanarity on-orbit detection method of the space thin film spliced multi-sub-mirror system according to claim 4, characterized in that: The measuring frame (1) is a light-weight high-rigidity structure.

6. The coplanarity on-orbit detection method of the space thin film spliced multi-sub-mirror system according to claim 4, characterized in that: The sensor (2) is a laser displacement sensor, which realizes non-contact measurement of the height of the top surface of the sub-mirror by using the laser triangulation principle.

7. The coplanarity on-orbit detection method of the space thin film spliced multi-sub-mirror system according to claim 4, characterized in that: The number of the sensors (2) should ensure that at least three sensors can work when measuring the center mirror (9) and each sub-mirror (8).

8. The coplanarity on-orbit detection method of the space thin film spliced multi-sub-mirror system according to claim 4, characterized in that: The rotary mechanism (3) starts to measure after rotating a certain angle, and the angle of rotation ensures that the sensor (2) can measure the height of the top surface of the next group of sub-mirrors (8), which is called the indexing angle.

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