Multi-stage compound posture control system precision ground test method

Abstract

The present application relates to the field of spacecraft attitude control system ground test technology, and specifically provides a kind of multistage compound attitude control system precision ground test method, first, build full physical simulation ground test platform, including on-orbit environment simulation system and multistage compound attitude control simulation system, two reference calibration devices are constructed using calibration two-axis photoelectric autocollimator, two measurement reference units are constructed using two-axis photoelectric autocollimator and polyhedral prism, based on cube, calibration two-axis photoelectric autocollimator and two-axis photoelectric autocollimator, the multistage compound attitude control simulation system is zero-position reference calibration and angle calibration, after calibration, control multistage compound attitude control simulation system moves from initial position to termination position, and angle information is collected by two measurement reference units respectively, and the attitude control precision is calculated according to angle information.The present application realizes the ground test of multistage compound attitude control system based on full physical simulation.

Description

Technical Field

[0001] This invention belongs to the field of ground testing technology for spacecraft attitude control systems, and particularly relates to a ground testing method for the accuracy of a multi-level composite attitude control system. Background Technology

[0002] With the continuous development of aerospace technology, the requirements for attitude control accuracy of spacecraft attitude control systems are becoming increasingly stringent, leading to the development of two-stage attitude control systems for spacecraft. A spacecraft attitude control system mainly consists of an attitude determination subsystem and an attitude control subsystem, with high-precision angular displacement sensors playing a crucial role in the attitude determination subsystem. To verify the impact of high-precision angular displacement sensors on the attitude control angular displacement accuracy of the two-stage attitude control system and to ensure the stable on-orbit operation of subsequent spacecraft, ground-based tests of the attitude control angular displacement accuracy of the two-stage attitude control system after the installation of high-precision angular displacement sensors are necessary.

[0003] Existing methods for ground testing of spacecraft attitude control accuracy include physical simulation, hardware-in-the-loop simulation, and digital simulation. Hardware-in-the-loop and digital simulation are more widely used, but both rely to varying degrees on establishing mathematical models. However, mathematical models struggle to fully and accurately describe the true characteristics of complex physical systems, and also cannot completely reproduce the characteristics of the space environment. This makes it difficult to fully expose potential problems in the system during testing. Physical simulation, on the other hand, is costly and difficult to implement, limiting its widespread application. Furthermore, existing methods for testing spacecraft attitude control accuracy are designed for single-stage spacecraft control systems and are not suitable for ground testing of attitude control accuracy in multi-stage composite attitude control systems.

[0004] Therefore, there is an urgent need for a ground-based testing method for the attitude control accuracy of a multi-level composite attitude control system. Summary of the Invention

[0005] In view of this, the present invention aims to provide a ground testing method for the accuracy of a multi-level composite attitude control system. By building a full-physical-level spacecraft multi-level attitude control accuracy testing platform, the on-orbit environment and control system are simulated, effectively reproducing the on-orbit working state of the spacecraft's multi-level attitude control system, thereby improving the reliability of ground test results, ensuring the stable operation of the spacecraft in orbit, and effectively reducing testing costs and implementation difficulty by using a dual-axis photoelectric autocollimator instead of a traditional laser interferometer and visual measurement system.

[0006] To achieve the above objectives, the technical solution created by this invention is implemented as follows:

[0007] This invention provides a ground-based method for testing the accuracy of a multi-level composite attitude control system, comprising:

[0008] S1: Build a ground test platform, including an on-orbit environment simulation system and a multi-level composite attitude control simulation system;

[0009] The on-orbit environment simulation system includes an air-bearing platform, an optical platform, and an air-bearing bearing mounted on the optical platform; the multi-level composite attitude control simulation system includes a primary control system for the satellite mounted on the air-bearing platform and a secondary control system for the load simulator mounted on the air-bearing bearing; the secondary control system for the load simulator includes a tracking and pointing mechanism and a cubic mirror, with the tracking and pointing mechanism rigidly connected to the cubic mirror.

[0010] S2: Construct a first reference calibration device using a first calibrated dual-axis photoelectric autocollimator; construct a measurement reference unit A using the first dual-axis photoelectric autocollimator and a first polyhedron; determine the position of the measurement reference unit A based on the optical transfer alignment of the cubic mirror, the first calibrated dual-axis photoelectric autocollimator, and the first dual-axis photoelectric autocollimator; perform zero-position reference calibration on the multi-level composite attitude control simulation system through the optical axis of the first dual-axis photoelectric autocollimator;

[0011] A second reference calibration device is constructed using a second calibrated dual-axis photoelectric autocollimator; a measurement reference unit B is constructed using a second dual-axis photoelectric autocollimator and a second polyhedron; the position of the measurement reference unit B is determined based on the optical transmission alignment of the cubic mirror, the second calibrated dual-axis photoelectric autocollimator, and the second dual-axis photoelectric autocollimator; and the multi-level composite attitude control simulation system is calibrated with a preset test angle through the optical axis of the second dual-axis photoelectric autocollimator.

[0012] S3: Control the multi-level composite attitude control simulation system to point to measurement reference unit A and measurement reference unit B in sequence. Use the first dual-axis photoelectric autocollimator and the second dual-axis photoelectric autocollimator to measure the angle information of the multi-level composite attitude control simulation system in sequence. Obtain the attitude control accuracy of the multi-level composite attitude control simulation system based on the output angle information.

[0013] Preferably, the air-bearing platform is a single-axis air-bearing platform, and the optical platform is a marble optical platform. Both the air-bearing platform and the optical platform are horizontally fixed on the vibration-isolated foundation. The air-bearing platform is used to provide on-orbit gravity conditions for the primary control system of the satellite. The air-bearing bearing is used to provide on-orbit gravity and friction conditions for the secondary control system of the load simulator.

[0014] Preferably, the tracking and pointing mechanism includes an angular displacement sensor and a dual-axis turntable, wherein the angular displacement sensor is mounted on the dual-axis turntable and is used to acquire the yaw angle of the azimuth axis of the dual-axis turntable in real time.

[0015] Preferably, a first multi-tooth indexing stage is set on the optical platform, and a first calibration biaxial photoelectric autocollimator is installed on the first multi-tooth indexing stage to form a first reference calibration device.

[0016] Preferably, the zero-position reference calibration of the multi-level composite attitude control simulation system is performed using the optical axis of the first dual-axis photoelectric autocollimator, including:

[0017] Adjust the optical axis of the first calibrated biaxial photoelectric autocollimator to be collinear with the normal of the center of the reference working surface of the cubic mirror to determine the zero reference.

[0018] A second multi-tooth indexing stage is set on the optical platform, and a first polyhedral prism is installed on the second multi-tooth indexing stage, such that the center normal of the first working surface of the first polyhedral prism is collinear with the optical axis of the first calibrated biaxial photoelectric autocollimator.

[0019] A first biaxial photoelectric autocollimator is set on the first polyhedral prism, such that the optical axis of the first biaxial photoelectric autocollimator is collinear with the normal of the center of the reference working surface of the cubic mirror, forming a measurement reference unit A.

[0020] Preferably, a third multi-tooth indexing stage is set on the optical platform, and a second calibration biaxial photoelectric autocollimator is installed on the third multi-tooth indexing stage to form a second reference calibration device.

[0021] Preferably, the multi-level composite attitude control simulation system is calibrated by pre-setting a test angle using the optical axis of the second dual-axis photoelectric autocollimator, including:

[0022] The optical axis of the second calibrated biaxial photoelectric autocollimator is made collinear with the second working surface of the first polyhedron by using the third multi-tooth indexing table;

[0023] The second calibration biaxial photoelectric autocollimator is rotated by a preset test angle using the third multi-tooth indexing table; a fourth multi-tooth indexing table is set on the optical platform, and a second polyhedral prism is installed on the fourth multi-tooth indexing table. The position of the fourth multi-tooth indexing table is adjusted so that the second working surface of the second polyhedral prism is collinear with the optical axis of the second calibration biaxial photoelectric autocollimator.

[0024] Adjust the position of the first reference calibration device on the optical platform and the angle of the first multi-tooth indexing table so that the optical axis of the first calibration biaxial photoelectric autocollimator is collinear with the first working surface of the second polyhedron.

[0025] Adjust the optical axis of the first calibrated biaxial photoelectric autocollimator to be collinear with the normal of the center of the reference working surface of the cubic mirror;

[0026] A second biaxial photoelectric autocollimator is set on the second polyhedron, so that the optical axis of the second biaxial photoelectric autocollimator is collinear with the normal of the center of the reference working surface of the cubic mirror, thus forming the measurement reference unit B.

[0027] Preferably, the preset test angle is 45 degrees.

[0028] Preferably, the first dual-axis photoelectric autocollimator and the second dual-axis photoelectric autocollimator sequentially measure the angle information of the multi-level composite attitude control simulation system, including:

[0029] When the multi-level composite attitude control simulation system points to the measurement reference unit A, the yaw angle of the multi-level composite attitude control simulation system is recorded multiple times using the first dual-axis photoelectric autocollimator of the measurement reference unit A.

[0030] When the multi-level composite attitude control simulation system points to the measurement reference unit B, the yaw angle of the multi-level composite attitude control simulation system is recorded multiple times using the second dual-axis photoelectric autocollimator of the measurement reference unit B.

[0031] Preferably, the attitude control accuracy of the multi-level composite attitude control simulation system is:

[0032] 3 +( - );

[0033] Among them, 3 For random error, The average yaw angle obtained by the first biaxial photoelectric autocollimator of the measurement reference unit A:

[0034] = ;

[0035] Where N represents the number of yaw angles collected. , … This represents the yaw angle collected by N when the multi-level composite attitude control simulation system sequentially points to the measurement reference unit A;

[0036] The average yaw angle obtained by the second biaxial photoelectric autocollimator of the measurement reference unit B:

[0037] = ;

[0038] in, , … This represents the yaw angle collected by N when the multi-level composite attitude control simulation system sequentially points to the measurement reference unit B.

[0039] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0040] First, this invention proposes a ground testing method based on full physical simulation for the performance verification of multi-level composite control systems, filling the gap in ground testing of multi-level composite attitude control systems. It simulates the on-orbit microgravity environment by combining a single-axis air-bearing platform with a high-load-bearing air-bearing bearing, replacing the complex gravity unloading device. A marble optical platform provides a high-flatness, vibration-isolated mounting reference for the entire system. By replacing part of the mathematical simulation with full physical simulation, it can more effectively reproduce the on-orbit working state of the spacecraft's multi-level attitude control system, significantly improving the reliability of ground test results for the multi-level composite attitude control system. This provides stronger ground verification support for the stable on-orbit operation of spacecraft, and the testing cost is lower and the testing process is simpler.

[0041] This invention uses a dual-axis photoelectric autocollimator for angle measurement. Compared with laser interferometers and vision measurement systems, it has higher measurement accuracy and resolution, and can directly read the values ​​without the need for complex displacement-angle conversion algorithms or image reconstruction algorithms. The data processing is simple and intuitive.

[0042] This invention utilizes the optical alignment transfer between a cubic mirror multifaceted prism and a dual-axis photoelectric autocollimator. It establishes two measurement reference units through a two-step method of zero-position reference calibration and angle calibration, minimizing systematic errors and eliminating random errors in angle measurement. Ultimately, it can accurately calibrate the rotation angle for attitude control accuracy testing, ensuring accurate measurement of the spacecraft's multi-level composite attitude control system from the initial position to the final position by measurement reference unit A and measurement reference unit B during the testing process. Attached Figure Description

[0043] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0044] Figure 1 This is a schematic diagram of zero-point reference calibration provided according to an embodiment of the present invention;

[0045] Figure 2 This is a schematic diagram of the 45° test angle calibration provided according to an embodiment of the present invention. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and do not constitute a limitation thereof. Similar elements in different embodiments are referred to by associated similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of the invention. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, some operations related to the invention are not shown or described in the specification. This is to avoid obscuring the core parts of the invention with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; the relevant operations can be fully understood based on the description in the specification and general technical knowledge in the art.

[0047] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined to form various implementations. Furthermore, the order of the steps or actions in the method description can be changed or adjusted in a manner readily apparent to those skilled in the art. Therefore, the various orders in the specification and drawings are merely for the clear description of a particular embodiment and do not imply a mandatory order, unless otherwise stated that a particular order must be followed.

[0048] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0049] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0050] The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0051] Please see Figure 1 and Figure 2 In one embodiment of the present invention, a ground-based method for testing the accuracy of a multi-level composite attitude control system is provided, comprising:

[0052] S1: Build a ground test platform, including an on-orbit environment simulation system and a multi-level composite attitude control simulation system;

[0053] The on-orbit environment simulation system includes an air-bearing platform, an optical platform, and an air-bearing bearing mounted on the optical platform; the multi-level composite attitude control simulation system includes a primary control system for the satellite mounted on the air-bearing platform and a secondary control system for the load simulator mounted on the air-bearing bearing; the secondary control system for the load simulator includes a tracking and pointing mechanism and a cubic mirror, with the tracking and pointing mechanism rigidly connected to the cubic mirror.

[0054] S2: Construct a first reference calibration device using a first calibrated dual-axis photoelectric autocollimator; construct a measurement reference unit A using the first dual-axis photoelectric autocollimator and a first polyhedron; determine the position of the measurement reference unit A based on the optical transfer alignment of the cubic mirror, the first calibrated dual-axis photoelectric autocollimator, and the first dual-axis photoelectric autocollimator; perform zero-position reference calibration on the multi-level composite attitude control simulation system through the optical axis of the first dual-axis photoelectric autocollimator;

[0055] A second reference calibration device is constructed using a second calibrated dual-axis photoelectric autocollimator; a measurement reference unit B is constructed using a second dual-axis photoelectric autocollimator and a second polyhedron; the position of the measurement reference unit B is determined based on the optical transmission alignment of the cubic mirror, the second calibrated dual-axis photoelectric autocollimator, and the second dual-axis photoelectric autocollimator; and the multi-level composite attitude control simulation system is calibrated with a preset test angle through the optical axis of the second dual-axis photoelectric autocollimator.

[0056] S3: Control the multi-level composite attitude control simulation system to point to measurement reference unit A and measurement reference unit B in sequence. Use the first dual-axis photoelectric autocollimator and the second dual-axis photoelectric autocollimator to measure the angle information of the multi-level composite attitude control simulation system in sequence. Obtain the attitude control accuracy of the multi-level composite attitude control simulation system based on the output angle information.

[0057] In step S1, the main task is to build a ground-based test platform for full physical simulation. This platform includes an on-orbit environment simulation system and a multi-level composite attitude control simulation system. The on-orbit environment simulation system is used to realize the spacecraft's on-orbit operating environment and achieve microgravity environment simulation. Specifically, the on-orbit environment simulation system includes a single-axis air-bearing platform, a high-load-bearing air-bearing bearing, and a marble optical platform. The single-axis air-bearing platform and the marble optical platform are both horizontally fixed on the vibration-isolated foundation of the laboratory. The high-load-bearing air-bearing bearing is set on the marble optical platform, which provides vibration isolation.

[0058] The multi-level composite attitude control simulation system includes a primary control system for the satellite and a secondary control system for the payload simulator. The primary control system is mounted on a single-axis air-bearing platform, which provides it with an on-orbit microgravity environment. The secondary control system for the payload simulator is mounted on a high-load-bearing air-bearing bearing, which provides it with an on-orbit microgravity and micro-friction environment. This embodiment of the invention uses a combination of air-bearing bearings and a single-axis air-bearing platform, replacing the complex gravity unloading device in existing technologies. This significantly reduces the difficulty and cost of implementing on-orbit environment simulation technology, while enhancing the versatility of the ground testing platform.

[0059] The primary control system of the spacecraft consists of the spacecraft and its primary control loop, used to simulate the free rotation state of the spacecraft in orbit. The secondary control system of the payload simulator includes an active pointing platform, a payload simulator, a secondary control loop for the payload simulator, and a tracking pointing mechanism. The active pointing platform is installed between the spacecraft and the payload simulator to achieve physical connection and control coupling between the primary control system of the spacecraft and the secondary control system of the payload simulator, jointly simulating the working mode of multi-level composite attitude control of the spacecraft in orbit. The payload simulator is used to simulate the payload characteristics of the spacecraft and can be adjusted according to the testing requirements of different spacecraft models. The tracking pointing mechanism includes an angular displacement sensor, a dual-axis turntable, a servo motor, a motion control unit, and a power drive unit. The angular displacement sensor, i.e., the optical payload, is installed on the azimuth axis of the dual-axis turntable to obtain the yaw angle of the turntable in real time. The ground test of this embodiment verifies the improvement of the attitude control pointing accuracy of the multi-level composite control system of the spacecraft by the high-precision angular displacement sensor. The multi-level composite attitude control simulation system achieves steering control through the sensing readings of an angular displacement sensor. In this embodiment of the invention, a measurement reference unit is constructed to measure the actual rotation of the multi-level composite attitude control simulation system. By comparing this measurement with the control parameters of the angular displacement sensor, the attitude control accuracy can be determined. The servo motor is a high-precision torque motor used to provide stable torque for the orientation axis of the dual-axis turntable. The motion control unit and power drive unit can drive the dual-axis turntable according to the specific rotation parameters of the angular displacement sensor.

[0060] To facilitate the determination of the actual pointing of the optical payload, a cubic mirror is also set in the secondary control system of the payload simulator in this embodiment of the invention. The cubic mirror is rigidly connected to the optical payload in the tracking pointing mechanism to form a whole, and they rotate together around the azimuth axis and pitch axis of the dual-axis turntable. Thus, the actual pointing of the optical payload can be characterized by the cubic mirror, which is convenient for subsequent angle calibration and ground testing of attitude control accuracy.

[0061] In step S2, a calibration and measurement platform needs to be built to calibrate the zero-position reference of the multi-level composite attitude control simulation system and determine the measurement reference unit B. Specifically, the calibration and measurement equipment includes multiple autocollimators and autocollimator software, multiple multi-tooth indexing tables, and multiple multi-faceted prisms. The autocollimators can accurately determine the angular offset of the measured object by measuring the position change of the reflected light spot. The multi-tooth indexing tables are used for high-precision angle adjustment and positioning. Among them, the autocollimators are divided into calibration dual-axis photoelectric autocollimators for calibration and dual-axis photoelectric autocollimators for measurement, according to their functions. The calibration of the dual-axis photoelectric autocollimator specifically includes a first calibration of the dual-axis photoelectric autocollimator and a second calibration of the dual-axis photoelectric autocollimator; the dual-axis photoelectric autocollimator specifically includes a first dual-axis photoelectric autocollimator and a second dual-axis photoelectric autocollimator; the multi-tooth indexing table includes a first multi-tooth indexing table, a second multi-tooth indexing table, a third multi-tooth indexing table, and a fourth multi-tooth indexing table; the multi-faceted prism includes a first multi-faceted prism (8 faces) and a second multi-faceted prism (8 faces).

[0062] In the zero-point reference calibration process, it is first necessary to build a zero-degree reference calibration platform. The first multi-tooth indexing table is placed horizontally on the marble optical platform, and the first calibration dual-axis photoelectric autocollimator is installed on the rotation axis of the first multi-tooth indexing table. It is ensured that the optical axis of the first calibration dual-axis photoelectric autocollimator intersects and is perpendicular to the rotation axis of the first multi-tooth indexing table. Finally, the first calibration dual-axis photoelectric autocollimator is locked and fixed on the first multi-tooth indexing table to form the first reference calibration device.

[0063] The cube mirror is used to characterize the maneuvering yaw angle of the multi-level composite attitude control simulation system. Specifically, the optical working surface of the cube mirror, which is perpendicular to the azimuth axis of the dual-axis turntable of the tracking and pointing mechanism, is defined as the reference working surface of the cube mirror.

[0064] After setting up the first reference calibration device, the first multi-tooth indexing stage is continuously adjusted to ensure that the optical axis of the first calibration dual-axis photoelectric autocollimator mounted on the first multi-tooth indexing stage is collinear with the center normal of the cubic mirror reference working surface on the multi-level composite attitude control simulation system. The collinearity adjustment process is as follows: the first calibration dual-axis photoelectric autocollimator is connected to the computer. When the crosshair image of the first calibration dual-axis photoelectric autocollimator displayed on the computer overlaps with the electronic crosshair in the center of the software interface of the first calibration dual-axis photoelectric autocollimator, and the crosshair image remains stable and still, it indicates that the first calibration dual-axis photoelectric autocollimator on the first reference calibration device and the reference working surface of the cubic mirror on the multi-level composite attitude control simulation system have achieved optical alignment.

[0065] A second multi-tooth indexing stage is placed on a marble optical platform, horizontally positioned along the reverse extension of the optical axis of the first calibrated biaxial photoelectric autocollimator. A first polyhedral prism, a regular octagonal prism, is provided, its lateral surfaces reflecting light. A central positioning hole is formed on the axis of the first polyhedral prism, through which it is mounted at the center of the upper surface of the second multi-tooth indexing stage. The first multi-tooth indexing stage is adjusted to rotate 180° precisely, thereby synchronously rotating the first calibrated biaxial photoelectric autocollimator mounted on it by 180°. By adjusting the angle of the second multi-tooth indexing stage, the central normal of the 0° reference working surface of the first multi-tooth prism is aligned with the optical axis of the first calibrated biaxial photoelectric autocollimator. The collinear adjustment process is as follows: Connect the first calibration dual-axis photoelectric autocollimator to the computer. When the crosshair image of the first calibration dual-axis photoelectric autocollimator displayed by the software on the computer overlaps with the electronic crosshair in the center of the software interface, and the crosshair image remains stable and still, it indicates that the first calibration dual-axis photoelectric autocollimator on the first reference calibration device has achieved optical alignment with the 0° reference working surface of the first multi-faceted prism on the second multi-tooth indexing stage.

[0066] A first biaxial photoelectric autocollimator is installed on the first polyhedron, ensuring that its optical axis intersects and is perpendicular to the rotation axis of the second multi-tooth indexing stage, and that its optical axis is collinear with the center normal of the cubic mirror reference working surface on the multi-level composite attitude control system. The collinearity adjustment process is as follows: connect the first biaxial photoelectric autocollimator to a computer. When the crosshair image of the first biaxial photoelectric autocollimator displayed on the computer software overlaps with the electronic crosshair in the center of the interface, and the crosshair image remains stable and stationary, it indicates that the first biaxial photoelectric autocollimator on the first polyhedron and the cubic mirror reference working surface on the multi-level composite attitude control system have achieved optical alignment.

[0067] After aligning the first dual-axis photoelectric autocollimator with the multi-level composite attitude control system, the first dual-axis photoelectric autocollimator and the first polyhedral prism are locked and fixed on the second multi-tooth indexing stage, forming measurement reference unit A. Through the adjustment of the above process, based on the optical transmission alignment of the cubic mirror, the first calibration dual-axis photoelectric autocollimator, and the first dual-axis photoelectric autocollimator, the position of measurement reference unit A can be determined. The optical axis of the first dual-axis photoelectric autocollimator is used to achieve zero-position reference calibration of the multi-level composite attitude control simulation system, providing a zero-position reference for subsequent ground testing of attitude control accuracy. That is, measurement reference unit A serves as the starting position in the subsequent testing process of the multi-level composite attitude control system.

[0068] Measurement reference unit A has a dual function: First, during the zero-degree reference calibration stage, the first polyhedron is used as the calibration object, and the first reference calibration device calibrates the first polyhedron to complete the calibration of measurement reference unit A; in the subsequent testing stage, the first dual-axis photoelectric autocollimator is used to read and record the angle information generated during the measurement process of the spacecraft multi-level composite attitude control simulation system.

[0069] During the angle calibration process, the first step is to determine the preset test angle. In this embodiment of the invention, the preset test angle is 45°. The attitude control accuracy of the spacecraft's multi-level composite attitude control simulation system is tested under a maneuver angle of 45° counterclockwise. The calibration platform required for the angle calibration process is built upon the zero-degree reference calibration platform.

[0070] A third multi-tooth indexing stage is provided and placed on a marble optical platform, positioned to one side of measurement reference unit A. A second calibration biaxial photoelectric autocollimator is then provided and mounted on the rotation axis of the third multi-tooth indexing stage, ensuring that the optical axis of the second calibration biaxial photoelectric autocollimator intersects and is perpendicular to the rotation axis of the third multi-tooth indexing stage. The second calibration biaxial photoelectric autocollimator is locked and fixed to the third multi-tooth indexing stage, forming the second reference calibration device. The third multi-tooth indexing stage is adjusted so that the optical axis of the second calibration biaxial photoelectric autocollimator is collinear with the center normal of the second working surface of the first polyhedral prism on measurement reference unit A. The collinear adjustment process is as follows: Connect the second calibration dual-axis photoelectric autocollimator to the computer. When the crosshair image of the second calibration dual-axis photoelectric autocollimator displayed by the software on the computer overlaps with the electronic crosshair in the center of the interface, and the crosshair image remains stable and still, it indicates that the second working surface of the first polyhedron on the measurement reference unit A is optically aligned with the second calibration dual-axis photoelectric autocollimator on the second reference calibration device.

[0071] After the measurement reference unit A is optically aligned with the second calibration biaxial photoelectric autocollimator on the second reference calibration device, the third multi-tooth indexing table is adjusted so that its indexing is accurate and rotated counterclockwise by 45°. This causes the second calibration biaxial photoelectric autocollimator mounted on the third multi-tooth indexing table to rotate counterclockwise by 45° synchronously, reaching the preset test angle.

[0072] A fourth multi-tooth indexing stage is set on a marble optical platform, and a second polyhedral prism is provided. The second polyhedral prism is a regular octagonal prism, and its lateral surfaces reflect light. A central positioning hole is opened on the axis of the second polyhedral prism, and the second polyhedral prism is installed at the center of the upper surface of the fourth multi-tooth indexing stage through the central positioning hole. By adjusting the position of the fourth multi-tooth indexing stage on the marble optical platform, the center normal of the second working surface of the second polyhedral prism placed on the fourth multi-tooth indexing stage is made collinear with the optical axis of the second calibration dual-axis photoelectric autocollimator. The collinearity adjustment process is as follows: the second calibration dual-axis photoelectric autocollimator is connected to the computer. When the crosshair image of the second calibration dual-axis photoelectric autocollimator displayed on the computer overlaps with the electronic crosshair in the center of the interface, and the crosshair image remains stable and still, it indicates that the second working surface of the second polyhedral prism is optically aligned with the second calibration dual-axis photoelectric autocollimator on the second reference calibration device.

[0073] The position of the first reference calibration device on the marble optical platform is further adjusted, and indexing is performed using the first multi-tooth indexing table, so that the optical axis of the first calibration biaxial photoelectric autocollimator on the first multi-tooth indexing table is collinear with the center normal of the 0° reference working surface of the second polyhedron on the fourth multi-tooth indexing table. The collinearity adjustment process is as follows: when the crosshair image of the first calibration biaxial photoelectric autocollimator displayed by the software of the first calibration biaxial photoelectric autocollimator on the computer overlaps with the electronic crosshair in the center of the interface, and the crosshair image remains stable and static, it indicates that the 0° reference working surface of the second polyhedron is optically aligned with the first calibration biaxial photoelectric autocollimator on the first reference calibration device.

[0074] After the second polyhedron is optically aligned with the first calibration dual-axis photoelectric autocollimator on the first reference calibration device, the first multi-tooth indexing stage is adjusted to rotate its indexing precisely by 180°, thereby causing the first calibration dual-axis photoelectric autocollimator on the first reference calibration device to rotate synchronously by 180°. Then, the single-axis air-bearing stage is rotated counterclockwise to make the optical axis of the first calibration dual-axis photoelectric autocollimator on the first reference calibration device collinear with the normal line of the center of the cubic mirror reference working surface on the attitude control simulation system. The collinearity adjustment process is as follows: when the crosshair image of the first calibration dual-axis photoelectric autocollimator displayed by the software of the first calibration dual-axis photoelectric autocollimator on the computer overlaps with the electronic crosshair in the center of the interface, and the crosshair image remains stable and still, it indicates that the first calibration dual-axis photoelectric autocollimator and the cubic mirror on the attitude control simulation system have achieved optical alignment.

[0075] A second dual-axis photoelectric autocollimator is provided and mounted on a fourth polyhedral prism. The second dual-axis photoelectric autocollimator is adjusted so that its optical axis is collinear with the normal to the center of the reference working surface of the cubic mirror on the multi-level composite attitude control system. The collinearity adjustment process is as follows: the second dual-axis photoelectric autocollimator is connected to a computer. When the crosshair image of the second dual-axis photoelectric autocollimator displayed on the computer software overlaps with the electronic crosshair in the center of the interface, and the crosshair image remains stable and static, it indicates that the second dual-axis photoelectric autocollimator and the cubic mirror on the multi-level composite attitude control system are optically aligned. Finally, the second dual-axis photoelectric autocollimator is locked and fixed on the fourth multi-tooth indexing table. The device consisting of the fourth multi-tooth indexing table, the second polyhedral prism, and the second dual-axis photoelectric autocollimator is called measurement reference unit B. Through the adjustments described above, based on the optical alignment of the cubic mirror, the second calibration dual-axis photoelectric autocollimator, and the second dual-axis photoelectric autocollimator, the position of measurement reference unit B can be determined. The optical axis of the second dual-axis photoelectric autocollimator is used to calibrate the multi-level composite attitude control simulation system at a preset test angle, providing a test angle reference for subsequent ground-based attitude control accuracy testing. In other words, measurement reference unit B serves as the termination position in the subsequent testing process of the multi-level composite attitude control system. At this point, with the center of the reference working surface of the cubic mirror on the multi-level composite attitude control simulation system as the vertex, the angle between the optical axis of the first dual-axis photoelectric autocollimator on measurement reference unit A and the optical axis of the second dual-axis photoelectric autocollimator on measurement reference unit B is 45°, completing the 45° angle calibration.

[0076] The embodiments of the present invention use optical transmission alignment and a combination of a dual-axis photoelectric autocollimator and a multi-faceted prism for angle calibration. Compared with other calibration methods such as theodolites, the calibrated angles are more accurate and reliable, and the calibration process is also simpler.

[0077] In step S3, after the zero-position reference calibration and 45° calibration in step S2, the multi-level composite attitude control simulation system is driven to perform a maneuver, realizing the ground test of the multi-level composite attitude control simulation system and determining the accuracy of the angular displacement sensor in the tracking and pointing mechanism. The maneuver test process of the multi-level composite attitude control simulation system is as follows:

[0078] By controlling the spacecraft to point to the reference position with a 0° yaw using the tracking pointing mechanism, the spacecraft's multi-stage composite attitude control simulation system is activated, and the system is then guided to point towards measurement reference unit A. After the multi-stage composite attitude control simulation system stabilizes, the initial position is zeroed, and relative mode control is performed before maneuvering begins. While the multi-stage composite attitude control simulation system is pointing towards measurement reference unit A, the yaw angle of the system is recorded multiple times using the first dual-axis photoelectric autocollimator of measurement reference unit A. The recorded yaw angle is... The instantaneous period is 10 seconds. The multi-level composite attitude control simulation system starts its maneuver from the initial position (pointing to measurement reference unit A), yaws counterclockwise by 45° to the final position, pointing the multi-level composite attitude control simulation system towards measurement reference unit B. After the multi-level composite attitude control simulation system stabilizes, the yaw angle of the multi-level composite attitude control simulation system is recorded multiple times using the second dual-axis photoelectric autocollimator of measurement reference unit B. The recorded yaw angle is... The instantaneous cycle is 10 seconds.

[0079] After obtaining the yaw angle data of the multi-level composite attitude control simulation system pointing to measurement reference unit A and pointing to measurement reference unit B, the attitude control accuracy of the multi-level composite attitude control simulation system is calculated based on the yaw angle data of measurement reference unit A and pointing to measurement reference unit B.

[0080] First, calculate the average yaw angle of the first biaxial photoelectric autocollimator on measurement reference unit A. :

[0081] = ;

[0082] Where N represents the number of yaw angles collected. , … This indicates the yaw angle collected by N when the multi-level composite attitude control simulation system sequentially points to the measurement reference unit A.

[0083] Calculate the average yaw angle of the second biaxial photoelectric autocollimator on measurement reference unit B. :

[0084] = ;

[0085] in, , … This represents the yaw angle collected by N when the multi-level composite attitude control simulation system sequentially points to the measurement reference unit B.

[0086] Average yaw angle and average yaw angle The difference is the systematic error. After adding random error, the attitude control accuracy of the multi-level composite attitude control simulation system can be obtained as follows:

[0087] 3 +( - );

[0088] Among them, 3 For random error, Empirical values ​​can be used, or the standard deviation of the yaw angle of the first and second dual-axis photoelectric autocollimators can be used to determine the value. Specifically, the standard deviation σ1 of the yaw angle obtained by the first dual-axis photoelectric autocollimator is calculated as follows:

[0089] σ1= ;

[0090] The standard deviation σ2 of the yaw angle obtained by the second biaxial photoelectric autocollimator is calculated as follows:

[0091] σ2= .

[0092] The value is the larger of the standard deviations of the yaw angle σ1 and σ2.

[0093] This invention establishes a full-physics testing platform in a laboratory environment and simulates the microgravity environment of a spacecraft in orbit. The full-physics testing platform reproduces the in-orbit working state of the spacecraft's multi-level composite control system, which is used to measure the angular displacement accuracy of the actual multi-level composite control system of the spacecraft, thus filling the gap in the field of full-physics simulation testing of the spacecraft's multi-level composite control system.

[0094] In summary, the above are merely preferred embodiments of this specification and are not intended to limit the scope of protection of this specification. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this specification should be included within the scope of protection of this specification.

[0095] The systems, apparatuses, modules, or units described in one or more of the above embodiments may be implemented by a computer chip or entity, or by a product having a certain function. A typical implementation device is a computer. Specifically, a computer may be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smartphone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or any combination of these devices.

[0096] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0097] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

Claims

1. A ground-based testing method for the accuracy of a multi-level composite attitude control system, characterized in that, include: S1: Build a ground test platform, including an on-orbit environment simulation system and a multi-level composite attitude control simulation system; The on-orbit environment simulation system includes an air-bearing platform, an optical platform, and an air-bearing bearing mounted on the optical platform; the multi-level composite attitude control simulation system includes a primary control system for the celestial body mounted on the air-bearing platform and a secondary control system for the load simulator mounted on the air-bearing bearing; the secondary control system for the load simulator includes a tracking and pointing mechanism and a cubic mirror, wherein the tracking and pointing mechanism is rigidly connected to the cubic mirror. S2: Construct a first reference calibration device using a first calibrated dual-axis photoelectric autocollimator; construct a measurement reference unit A using the first dual-axis photoelectric autocollimator and a first polyhedron; determine the position of the measurement reference unit A based on the optical transfer alignment of the cubic mirror, the first calibrated dual-axis photoelectric autocollimator, and the first dual-axis photoelectric autocollimator; perform zero-position reference calibration on the multi-level composite attitude control simulation system through the optical axis of the first dual-axis photoelectric autocollimator; A second reference calibration device is constructed using a second calibrated dual-axis photoelectric autocollimator; a measurement reference unit B is constructed using the second dual-axis photoelectric autocollimator and a second polyhedron; the position of the measurement reference unit B is determined based on the optical transmission alignment of the cubic mirror, the second calibrated dual-axis photoelectric autocollimator, and the second dual-axis photoelectric autocollimator; and the multi-level composite attitude control simulation system is calibrated with a preset test angle through the optical axis of the second dual-axis photoelectric autocollimator. S3: Control the multi-level composite attitude control simulation system to point sequentially to measurement reference unit A and measurement reference unit B, and measure the angle information of the multi-level composite attitude control simulation system sequentially through the first dual-axis photoelectric autocollimator and the second dual-axis photoelectric autocollimator, and obtain the attitude control accuracy of the multi-level composite attitude control simulation system based on the output angle information.

2. The ground testing method for the accuracy of the multi-level composite attitude control system according to claim 1, characterized in that, The air-bearing platform is a single-axis air-bearing platform, and the optical platform is a marble optical platform. Both the air-bearing platform and the optical platform are horizontally fixed on a vibration-isolated foundation. The air-bearing platform is used to provide on-orbit gravity conditions for the primary control system of the satellite. The air-bearing bearing is used to provide on-orbit gravity and friction conditions for the secondary control system of the load simulator.

3. The ground testing method for the accuracy of a multi-level composite attitude control system according to claim 1, characterized in that, The tracking and pointing mechanism includes an angular displacement sensor and a dual-axis turntable. The angular displacement sensor is mounted on the dual-axis turntable and is used to obtain the yaw angle of the azimuth axis of the dual-axis turntable in real time.

4. The ground testing method for the accuracy of the multi-level composite attitude control system according to claim 1, characterized in that, A first multi-tooth indexing stage is set on the optical platform, and a first calibration biaxial photoelectric autocollimator is installed on the first multi-tooth indexing stage to form a first reference calibration device.

5. The ground testing method for the accuracy of the multi-level composite attitude control system according to claim 4, characterized in that, The zero-position reference calibration of the multi-level composite attitude control simulation system using the optical axis of the first dual-axis photoelectric autocollimator includes: Adjust the optical axis of the first calibrated biaxial photoelectric autocollimator to be collinear with the normal of the center of the reference working surface of the cubic mirror to determine the zero reference. A second multi-tooth indexing stage is set on the optical platform, and a first multi-faceted prism is installed on the second multi-tooth indexing stage, such that the center normal of the first working surface of the first multi-faceted prism is collinear with the optical axis of the first calibrated biaxial photoelectric autocollimator. A first biaxial photoelectric autocollimator is set on the first polyhedral prism, such that the optical axis of the first biaxial photoelectric autocollimator is collinear with the normal of the center of the reference working surface of the cubic mirror, thus forming a measurement reference unit A.

6. The ground testing method for the accuracy of a multi-level composite attitude control system according to claim 5, characterized in that, A third multi-tooth indexing stage is set on the optical platform, and a second calibration biaxial photoelectric autocollimator is installed on the third multi-tooth indexing stage to form a second reference calibration device.

7. The ground testing method for the accuracy of a multi-level composite attitude control system according to claim 6, characterized in that, The step of calibrating the multi-level composite attitude control simulation system by setting a preset test angle using the optical axis of the second dual-axis photoelectric autocollimator includes: The optical axis of the second calibrated biaxial photoelectric autocollimator is made collinear with the second working surface of the first polyhedron by using the third multi-tooth indexing table; The second calibration biaxial photoelectric autocollimator is rotated by a preset test angle using a third multi-tooth indexing table; a fourth multi-tooth indexing table is set on the optical platform, and a second polyhedral prism is installed on the fourth multi-tooth indexing table; the position of the fourth multi-tooth indexing table is adjusted so that the second working surface of the second polyhedral prism is collinear with the optical axis of the second calibration biaxial photoelectric autocollimator. Adjust the position of the first reference calibration device on the optical platform and the angle of the first multi-tooth indexing table so that the optical axis of the first calibration biaxial photoelectric autocollimator is collinear with the first working surface of the second polyhedron. Adjust the optical axis of the first calibrated biaxial photoelectric autocollimator to be collinear with the normal of the center of the reference working surface of the cubic mirror; A second biaxial photoelectric autocollimator is set on the second polyhedron, such that the optical axis of the second biaxial photoelectric autocollimator is collinear with the normal of the center of the reference working surface of the cubic mirror, thus forming a measurement reference unit B.

8. The ground testing method for the accuracy of a multi-level composite attitude control system according to claim 1, characterized in that, The preset test angle is 45 degrees.

9. The ground testing method for the accuracy of a multi-level composite attitude control system according to claim 1, characterized in that, The first dual-axis photoelectric autocollimator and the second dual-axis photoelectric autocollimator sequentially measure the angle information of the multi-level composite attitude control simulation system, including: When the multi-level composite attitude control simulation system points to the measurement reference unit A, the yaw angle of the multi-level composite attitude control simulation system is recorded multiple times using the first dual-axis photoelectric autocollimator of the measurement reference unit A. When the multi-level composite attitude control simulation system points to the measurement reference unit B, the yaw angle of the multi-level composite attitude control simulation system is recorded multiple times using the second dual-axis photoelectric autocollimator of the measurement reference unit B.

10. The ground testing method for the accuracy of a multi-level composite attitude control system according to claim 9, characterized in that, The attitude control accuracy of the multi-level composite attitude control simulation system is: 3 +（ - )； Among them, 3 For random error, The average yaw angle obtained by the first biaxial photoelectric autocollimator of the measurement reference unit A: = ； Where N represents the number of yaw angles collected. , … This indicates the yaw angle collected by N when the multi-level composite attitude control simulation system sequentially points to the measurement reference unit A; The average yaw angle obtained by the second biaxial photoelectric autocollimator of the measurement reference unit B: = ； in, , … This indicates the yaw angle collected by N when the multi-level composite attitude control simulation system sequentially points to the measurement reference unit B.

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