Detection method of spatial large-scale antenna and ground semi-physical experiment verification system

Abstract

The invention discloses a space large-scale antenna detection method and a ground semi-physical experiment verification system, and the method comprises the steps: designing an improved LQR controller for a detection satellite and a target antenna in an actual space environment, and enabling the detection satellite and the target antenna to be suspended at an expected position when the target antenna is suspended at an expected position; controlling the detection satellite to perform attitude and orbit control according to the expected trajectory so as to detect the target antenna; in the system, the verification of the detection method is realized through the design of a ground measurement system, an air floatation simulation system, a ground control system, a detection satellite simulator and a target antenna simulator. The detection method has the advantages of flexible parameter adjustment, high automation, high detection efficiency and the like, and errors and risks caused by manual detection can be reduced; the verification system uses the air floating platform to simulate the zero friction phenomenon in the space, and the air floating satellite simulates the real satellite operation environment, so that the effectiveness and accuracy of the detection method can be verified efficiently and at low cost through experiments.

Description

Technical Field

[0001] The present invention belongs to the field of aerospace technology, and in particular relates to a detection method for a large-scale space antenna and a ground-based semi-physical experimental verification system. Background Art

[0002] As a key component of satellite communication systems, antennas are primarily used to receive and transmit radio waves, enabling signal transmission between ground stations and satellites. They are widely used in civil, commercial, and military fields. However, large-scale antennas in space may be subject to micrometeorite impacts, and thermal expansion and contraction due to temperature changes can cause cracks on their surfaces. Vibrations experienced during launch, orbital insertion, and operation, as well as impacts on the payload, can cause deformation and displacement on the surface. Therefore, it is necessary to design an efficient, accurate, and highly adaptable detection method for the detection of large-scale antennas in space. This detection method is required to not only be able to promptly detect and locate abnormal changes on the antenna, providing key data support for subsequent maintenance and repair, but also to continuously monitor the antenna's health to ensure its long-term stable operation in the complex space environment.

[0003] Testing large-scale antennas in space presents significant difficulties and challenges for human operators. First, large-scale antennas are often mounted on satellites in orbit far from Earth, making direct access and inspection nearly impossible. Second, antennas have large surface areas and complex structures, requiring extensive inspection. Manual inspection often struggles to achieve comprehensive coverage, leading to potential issues being missed. Given these challenges, it is crucial to develop a method that can automatically, efficiently, and accurately inspect large-scale antennas. This method must be able to comprehensively inspect the antennas along their desired trajectory. This automated inspection process improves efficiency and reduces the errors and risks associated with human error. Therefore, it is necessary to develop a method for inspecting large-scale antennas that can replace traditional manual inspection methods, improve accuracy and reliability, and provide strong support for the stable operation of space communication systems. Furthermore, to avoid the high cost of repeated verification during the development process, a semi-physical experimental verification system that simulates the space environment is needed to verify the validity of the designed inspection method, reduce experimental duplication, and save experimental costs. Summary of the Invention

[0004] The purpose of the present invention is to provide a detection method for large-scale space antennas and a ground-based semi-physical experimental verification system to overcome the problems of difficult manual operation and low detection efficiency in the current large-scale antenna detection process, while solving the problem of high cost caused by experimental repetitiveness.

[0005] In order to achieve the above tasks, the present invention adopts the following technical solutions:

[0006] A method for detecting a large-scale spatial antenna, comprising:

[0007] For the detection satellite and target antenna in the actual space environment, an improved LQR controller is designed to control the detection satellite to perform attitude and orbit control according to the desired trajectory when the target antenna is suspended at the expected position, thereby detecting the target antenna. The design process of the improved LQR controller is as follows:

[0008] First, the system dynamic equations of the detection satellite and target antenna are constructed, with the detection satellite's measured trajectory as the output variable, the detection satellite's thrust control amount as the control variable, and the detection satellite's preset expected trajectory as the ideal state variable. The difference between the ideal state variable and the output variable is used to construct an error function. Based on the error function and the control variable, a performance index is constructed. The optimal control output corresponds to the minimum performance index.

[0009] The Hamiltonian function and the canonical equations of the co-state variables and the actual posture are established. The control equation is constructed by taking partial derivatives of the Hamiltonian function on the control variables, thereby obtaining the relationship between the optimal control output and the optimal co-state variables. The solution matrix and feedforward compensation term of the Riccati equation are introduced into the expression of the optimal co-state variables. The relationship between the optimal control output and the solution matrix and feedforward compensation term is obtained through derivation calculation and recursion, thereby solving the optimal control output for trajectory and attitude control of the detection satellite.

[0010] Furthermore, the detection of the target antenna includes detecting the communication interconnection between the satellite and the target antenna, and detecting the attitude and orbit control of the satellite; at the same time, the detection satellite captures the actual condition of the target antenna through an onboard camera, and transmits the captured image back according to a real-time communication system.

[0011] Furthermore, the performance indicators are:

[0012]

[0013] in, Represents the time from the initial time t0 to the terminal time t f The integral of the error function e(t) = z(t)-y(t) requires the optimal control output u * (t), so that the performance index J is minimized; Q is the state error weight matrix, R is the control input weight matrix; z(t) is the desired trajectory, y(t) is the output variable, and u(t) is the control variable.

[0014] Furthermore, the Hamiltonian function is as follows:

[0015]

[0016] Where λ(t) refers to the covariate variable and the canonical equation is:

[0017]

[0018] Among them, x * (t) is the optimal actual posture, indicating the optimal control output u * The optimal state variable under (t); λ * (t) represents the optimal co-state variable, A is the state transfer matrix, and B is the control input matrix.

[0019] Furthermore, the control equation is constructed by taking partial derivatives of the control variables, thereby obtaining the relationship between the optimal control output and the optimal co-state variable; the solution matrix of the Riccati equation and the feedforward compensation term are introduced into the expression of the optimal co-state variable, including:

[0020]

[0021] From this we get:

[0022] u * (t)=-R -1 B T λ * (t)

[0023] Since the canonical equation is a linear equation, assume that:

[0024] λ * (t) = P(t)x * (t)-g(t)

[0025] Where P(t) is the solution matrix of the Riccati equation, and g(t) is the feedforward compensation term.

[0026] Furthermore, by * (t) = P(t)x * (t)-g(t) is differentiated and brought into the Hamiltonian function and the canonical equation to obtain:

[0027] -P(t)AA T P(t)+P(t)BR -1 B T P(t)-Q=0

[0028] g(t)=[A T -P(t)BR -1 B T ] -1 Qz(t)

[0029] Then the optimal control output for the detection satellite is:

[0030] u * (t)=-R -1 BT [P(t)x * (t)-g(t)].

[0031] Furthermore, the ground control console plans the trajectory of the detection satellite to obtain the expected trajectory z(t) of the detection satellite; the sensor on board the detection satellite obtains the measurement trajectory y(t) of the detection satellite, and the error between the two is taken as e(t); the control variable u(t) of the detection satellite is obtained as [F x ,F y ,F z ] T , which means the output component of the control force generated by the cold jet thruster in the x, y, and z directions; e(t) and u(t) are input into the improved LQR controller to calculate the optimal control output u * (t) is [F cx ,F cy ,F cz ] T , that is, the thrust components applied by the cold jet propulsion in the x, y, and z directions; using the optimal control output u * (t) Adjust the position and attitude information of the entire detection satellite relative to the target antenna to realize the trajectory control of the detection satellite; during the flyby observation process, the onboard camera on the detection satellite captures the surface image of the target antenna in real time, which is then encoded and transmitted to the ground control console through the communication module. The ground end decodes the image and analyzes the deformation and displacement parameters of the target antenna.

[0032] A ground semi-physical experimental verification system includes: a ground measurement system, an air flotation simulation system, a ground control system, a detection satellite simulator and a target antenna simulator, wherein:

[0033] The ground measurement system is used to determine the real-time trajectory of the detection satellite simulator and the target antenna simulator; the flotation simulation system is used to simulate the actual space environment and provide operational support for the detection satellite simulator and the target antenna simulator; the ground control system is used to control the target antenna simulator, plan the desired trajectory of the detection satellite simulator, use the improved LQR controller to control the trajectory of the detection satellite simulator, receive the observation data of the target antenna simulator from the detection satellite simulator and perform data analysis; the detection satellite simulator and the target antenna simulator are used to simulate the detection satellite and target antenna in the actual space environment, respectively.

[0034] Furthermore, the ground measurement system includes a support frame arranged around the air flotation simulation system, and a plurality of motion capture cameras are mounted on the support frame via a pan / tilt platform; the motion capture cameras are used to capture the measurement trajectory of the detection satellite simulator in real time;

[0035] The air flotation simulation system includes an air flotation platform, on which the detection satellite simulator and the target antenna simulator are placed. The air flotation platform provides a frictionless environment and multi-degree-of-freedom motion conditions for the operation of the detection satellite simulator and the target antenna simulator.

[0036] Furthermore, the structures of the detection satellite simulator and the target antenna simulator are basically the same, both including a satellite shell, a cold jet propulsion system, an industrial computer control card, a gas cylinder, an air foot, a battery, a check valve, and a high-pressure inflation valve, wherein the air foot and the cold jet propulsion system are controlled by the industrial computer control card, and the industrial computer control card realizes information interaction with the ground measurement system through a wireless module; the cold jet propulsion system is installed in the satellite shell to generate a three-axis output component of the control force; the air foot is arranged at the bottom of the satellite shell to cooperate with the air flotation platform to produce suspension; through the coordination of the cold jet propulsion system and the air foot, the motion control and attitude adjustment of the detection satellite simulator and the target antenna simulator are realized; the gas cylinder is used to provide high-pressure gas supply to the air foot, and the high-pressure gas cylinder is used to replenish the high-pressure gas into the gas cylinder through the check valve and the high-pressure inflation valve; the battery is used to provide power for the cold jet propulsion system, the industrial computer control card and the air foot;

[0037] The unique structure of the target antenna simulator is the satellite antenna arranged on the top of the satellite shell and the solar panels arranged on both sides of the satellite shell; the unique structure of the detection satellite simulator is the detection camera installed on the top of the satellite shell, which is used to obtain observation data of the target antenna simulator.

[0038] Furthermore, the target antenna simulator receives the control signal from the ground control system, moves on the surface of the air flotation platform through the air foot to reach the specified position for suspension, and serves as the target satellite; the ground control system generates the expected trajectory of the detection satellite simulator, captures the measured trajectory of the detection satellite simulator in real time through the motion capture camera, inputs the error function of the expected trajectory and the measured trajectory, and the control variables of the detection satellite into the improved LQR controller to calculate the optimal control output, and uses the optimal control output to control the detection satellite simulator so that the detection satellite simulator flies around the target antenna simulator; at the same time, the observation data of the target antenna simulator is obtained through the detection camera carried by the detection satellite simulator, and transmitted to the ground control system; in the ground control system, the measured trajectory of the detection satellite simulator is compared with the expected trajectory to verify the accuracy of the detection method.

[0039] A terminal device includes a processor, a memory, and a computer program stored in the memory; when the processor executes the computer program, the detection method of the spatial large-scale antenna is implemented.

[0040] A computer-readable storage medium stores a computer program; when the computer program is executed by a processor, the method for detecting a spatial large-scale antenna is implemented.

[0041] Compared with the prior art, the present invention has the following technical features:

[0042] The proposed method, based on an improved LQR control strategy, sets a detection satellite simulator to perform state detection on a target antenna simulator along a desired trajectory. This method offers advantages such as flexible parameter adjustment, high automation, and high detection efficiency, reducing the errors and risks associated with manual detection. A ground-based semi-physical experimental verification system was also designed, using an air-floating platform to simulate zero-friction space phenomena and an air-floating satellite to simulate the operating environment of a real satellite. The goal was to experimentally verify the effectiveness and accuracy of the detection method. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Flow chart of the detection method;

[0044] Figure 2 It is the control strategy flow chart;

[0045] Figure 3 This is a schematic diagram of the target antenna simulator;

[0046] Figure 4 Schematic diagram of the satellite simulator for testing;

[0047] Figure 5 The overall physical diagram of the semi-physical experiment verification system;

[0048] Figure 6 A schematic diagram of the modular system for semi-physical experiment verification;

[0049] Figure 7 This is a schematic diagram of the semi-physical experiment verification system operation process;

[0050] Figure 8 The overall flow chart of the semi-physical experiment verification system;

[0051] Figure 9 is the actual running trajectory;

[0052] Figure 10 To detect the attitude and orbit changes of the satellite simulator.

[0053] Explanation of the numbers in the figure: 1 motion capture camera, 2 support frame, 3 air flotation platform, 4 detection satellite simulator, 5 target antenna simulator, 6 pan-tilt platform, 7 satellite antenna, 8 satellite shell, 9 solar sail panel, 10 cold jet propulsion, 11 industrial computer control card, 12 gas cylinder, 13 gas foot, 14 battery, 15 check valve, 16 high-pressure inflation valve, 17 detection camera, 18 host computer. DETAILED DESCRIPTION

[0054] The present invention first provides a detection method for large-scale antennas suitable for actual space environments. The detection method is based on a detection satellite and a target antenna. To address the problems of external interference and model uncertainty caused by the detection satellite's orbital flight, an improved LQR controller is designed to control the detection satellite to perform attitude and orbit control along a desired trajectory when the target antenna is suspended at an expected position, thereby detecting the target antenna. The detection process includes communication interconnection between the detection satellite and the target antenna, and attitude and orbit control of the detection satellite. At the same time, the detection satellite captures the actual condition of the target antenna through an onboard camera, and transmits the captured image back according to a real-time communication system for subsequent image analysis and determination of the target antenna detection status.

[0055] The design process of the improved LQR controller is as follows:

[0056] During the actual operation of the detection satellite and target antenna, in addition to the hard indicator of tracking accuracy, propellant consumption is also an important indicator. Therefore, the improved optimal control algorithm LQR control is selected as the control algorithm of this detection method, while considering the control amount of trajectory error and thruster consumption during operation; when the improved LQR controller is used for trajectory tracking, a feedforward controller needs to be designed based on the reference input. At this time, the LQR tracker is an LQR controller with feedforward, that is, the state feedback corresponding to the LQR controller plus the feedforward control related to the reference input.

[0057] First, construct the system dynamic equation as:

[0058]

[0059] y(t)=Cx(t) (2)

[0060] In this solution, the superscript dot on a parameter indicates the derivative of the parameter, the superscript T on a parameter indicates the transpose, the superscript * indicates the optimal solution, and the superscript -1 indicates the inverse matrix. The same applies below.

[0061] In the above formula, x(t) is the state variable, which represents the actual trajectory of the detection satellite at time t; y(t) is the output variable, which represents the measured trajectory of the detection satellite detected by the sensor; u(t) is the control variable, which represents the thrust control amount of the cold jet propulsion system carried by the detection satellite; A is the state transfer matrix, which describes the dynamic characteristics of the detection satellite on the air-floating platform; B is the control input matrix, which reflects the mapping relationship between thrust and posture changes; C is the output matrix, which describes the mapping relationship between the state variable x(t) and the output variable y(t).

[0062] The entire system is fully observable and controllable. The initial state variable is x0(t), the ideal state variable is the expected trajectory and z(t); u(t) is unconstrained and the terminal performance index is not considered, so the performance index is:

[0063]

[0064] in, Represents the time from the initial time t0 to the terminal time t f The integral of is used for global performance optimization; the error function e(t)=z(t)-y(t) requires the optimal control output u * (t), so that the performance index J is minimized; Q is the state error weight matrix, which is used to adjust the weight of each state variable error; R is the control input weight matrix, which is used to adjust the energy consumption of the control input.

[0065] Create the Hamiltonian function:

[0066]

[0067] Where λ(t) refers to the covariate variable, which is used to construct the adjoint equation of the optimal control problem; thus, the canonical equation is obtained:

[0068]

[0069] Among them, x * (t) represents the optimal actual posture, which represents the optimal control output u * The optimal state variable under (t); u * (t) is obtained by minimizing the performance index J; λ * (t) represents the optimal covariate variable. Since the terminal index is not considered, the transversality condition is not considered.

[0070] Since u(t) is unconstrained, the governing equation holds, namely:

[0071]

[0072] From this we get:

[0073] u * (t)=-R -1 B T λ * (t) (7)

[0074] Since the canonical equation is a linear equation, assume that:

[0075] λ * (t) = P(t)x * (t)-g(t) (8)

[0076] Where P(t) is the solution matrix of the Riccati equation, which is obtained by solving the nonlinear differential equation of Equation (12) and is used to construct the optimal feedback control law; g(t) is the feedforward compensation term, which is an unknown function related to the ideal state variable z(t) and is used to eliminate the tracking error;

[0077] Taking the derivative of formula (8), we get:

[0078]

[0079] Substituting equations (5) and (8) into equation (9), we can obtain:

[0080]

[0081] Substituting equations (4) and (8) into equation (10), we can obtain:

[0082]

[0083] Formula (10) should be valid at any time and in any state, so the corresponding terms on both sides of the equation should be equal, thus we can get:

[0084] -P(t)AA T P(t)+P(t)BR -1 B T P(t)-Q=0 (12)

[0085] g(t)=[A T -P(t)BR -1 B T ] -1 Qz(t) (13)

[0086] where R -1 Is the inverse matrix of the control input weight matrix R; K = -R -1 B T is the feedback gain matrix, which is used to map the state error to the control input;

[0087] The optimal control output for the detection satellite is obtained as follows:

[0088] u * (t)=-R -1 B T [P(t)x * (t)-g(t)] (14)

[0089] like Figure 2 As shown, for the target antenna in the actual space environment, the specific detection method is as follows:

[0090] First, the ground control console plans the trajectory of the detection satellite to obtain the expected trajectory z(t) of the detection satellite; the sensor on board the detection satellite obtains the measurement trajectory y(t) of the detection satellite, and the error between the two [x e ,y e ,ψ e ] T As e(t); where x e is the error in the x direction, y e is the error in the y direction, ψ e is the angle error; the control variable u(t) of the detection satellite is obtained as [F x ,F y ,F z ] T , which means the output component of the control force generated by the cold jet thruster in the three directions of x, y, and z; input e(t) and u(t) into the improved LQR controller and calculate the optimal control output u through formula (14): * (t) is [F cx ,F cy ,F cz ] T , that is, the thrust components applied by the cold jet propulsion in the x, y, and z directions; using the optimal control output u * (t) Adjust the position and attitude information of the detection satellite relative to the target antenna to realize the trajectory control of the detection satellite; during the flyby observation process, the onboard camera on the detection satellite takes real-time images of the target antenna surface, which are encoded and transmitted to the ground control console through the communication module. The ground end decodes the images and analyzes the deformation, displacement and other parameters of the target antenna.

[0091] The preliminary design of this detection method has been completed. This method incorporates satellite control strategy research, intersatellite communication interconnection, high-precision image processing technology, and a real-time control system to avoid the high costs associated with experimental repetitiveness during the design and verification of the detection method. Building on the aforementioned technical solution, the present invention further proposes a ground-based semi-physical experimental verification system to verify the effectiveness of the designed detection method. The core components of this experimental system are an air-floating satellite and an air-floating platform, which not only perform large-scale antenna positioning but also simulate the microgravity environment of space. The air-floating platform, a key foundation of the experimental system, possesses high-precision and high-stability motion control capabilities. The precise air-floating system achieves frictionless levitation, enabling high-precision displacement and attitude adjustment over a wide range. The air-floating satellite, another core component of the experimental system, simulates the operational state of a real satellite. Through its internal control system, the air-floating satellite can simulate various satellite motion states in orbit, including attitude adjustment and orbital changes.

[0092] See also Figures 3 to 5The present invention provides a ground semi-physical experimental verification system, comprising: a ground measurement system, an air flotation simulation system, a ground control system, a detection satellite simulator 4 and a target antenna simulator 5, wherein:

[0093] The ground measurement system is used to determine the real-time trajectory of the detection satellite simulator 4 and the target antenna simulator 5; the flotation simulation system is used to simulate the actual space environment and provide operation support for the detection satellite simulator 4 and the target antenna simulator 5; the ground control system is used to control the target antenna simulator 5, plan the expected trajectory of the detection satellite simulator 4, use the improved LQR controller to control the trajectory of the detection satellite simulator 4, receive the observation data of the detection satellite simulator 4 on the target antenna simulator 5 and perform data analysis; the detection satellite simulator 4 and the target antenna simulator 5 are used to simulate the detection satellite and target antenna in the actual space environment, respectively.

[0094] Specifically, the ground measurement system includes a support frame 2 arranged around the flotation simulation system, and multiple motion capture cameras 1 are mounted on the support frame 2 through a pan-tilt head 6; the measurement trajectory of the detection satellite simulator 4 is captured in real time by the motion capture camera 1, and the measurement trajectory is compared with the expected trajectory to verify the accuracy of the detection method.

[0095] The air flotation simulation system includes an air flotation platform 3, on which the detection satellite simulator 4 and the target antenna simulator 5 are placed. The air flotation platform 3 provides a frictionless environment and multi-degree-of-freedom motion conditions for the operation of the detection satellite simulator 4 and the target antenna simulator 5.

[0096] The structures of the detection satellite simulator 4 and the target antenna simulator 5 are basically the same, and both include a satellite shell 8, a cold jet thruster 10, an industrial computer control card 11, a gas cylinder 12, a gas foot 13, a battery 14, a check valve 15, and a high-pressure inflation valve 16. The gas foot 13 and the cold jet thruster 10 are controlled by the industrial computer control card 11, and the industrial computer control card 11 realizes information exchange with the ground measurement system through a wireless module; the cold jet thruster 10 is installed in the satellite shell 8 and is used to generate a three-axis output component of the control force; The gas foot 13 is arranged at the bottom of the satellite shell 8 and is used to cooperate with the air flotation platform 3 to produce suspension; through the coordination of the cold jet thruster 10 and the gas foot 13, the motion control and attitude adjustment of the detection satellite simulator 4 and the target antenna simulator 5 are realized; the gas cylinder 12 is used to provide high-pressure gas supply to the gas foot 13, and the high-pressure gas cylinder is used to replenish the high-pressure gas into the gas cylinder 12 through the check valve 15 and the high-pressure filling valve 16; the battery 14 is used to provide power for the cold jet thruster 10, the industrial computer control card 11 and the gas foot 13.

[0097] Building on the aforementioned common structure, the target antenna simulator 5 features a satellite antenna 7 mounted on top of a satellite housing 8 and solar panels 9 on either side of the housing. The satellite antenna 7 is used to generate a preset deformation pattern, while the solar panels 9 simulate space thermal load disturbances. The detection satellite simulator 4 features a detection camera 17 mounted on top of the satellite housing 8, which is used to acquire observation data from the target antenna simulator 5.

[0098] The ground control system mainly includes a host PC 18 for overall control of the system.

[0099] like Figures 6 to 8 As shown, the verification process of the detection method using the above system is as follows:

[0100] The target antenna simulator 5 receives the control signal from the ground control system, moves on the surface of the air flotation platform 3 through the air foot 13 to reach the specified position for suspension, and serves as the target satellite; the ground control system generates the expected trajectory of the detection satellite simulator 4, and captures the measured trajectory of the detection satellite simulator 4 in real time through the motion capture camera 1, and inputs the error function of the expected trajectory and the measured trajectory, as well as the control variables of the detection satellite into the improved LQR controller to calculate the optimal control output, and uses the optimal control output to control the detection satellite simulator 4 so that the detection satellite simulator 4 flies around the target antenna simulator 5; at the same time, the observation data of the target antenna simulator 5 is obtained through the detection camera 17 carried by the detection satellite simulator 4, and transmitted to the ground control system; the measured trajectory of the detection satellite simulator 4 is compared with the expected trajectory in the host computer 18 to verify the accuracy of the proposed detection method.

[0101] Figure 9 In order to verify the actual operation trajectory of the above detection method in this verification system, Figure 10 In order to use this detection method to detect the attitude and orbit changes of the detection satellite during actual operation, it can be seen that under this strategy, it presents a relatively stable feature compared with the expected trajectory. The detection satellite can fly around according to the predetermined trajectory, and the deviation during the fly-around process is small. The operation results of the above detection method in the actual semi-physical experimental verification system are analyzed, and it can be concluded that the average error in the x-direction is 6.34mm, the average error in the y-direction is 7.31mm, and the angle is The average error was 2.23°, indicating that the error of the initially designed detection method was extremely low, meeting the expected requirements. This validates the accuracy of the detection method and the effectiveness of the semi-physical experimental verification system. This detection method can be implemented on space satellites to achieve highly automated satellite detection. The designed fly-by detection mechanism enables comprehensive detection of the target antenna. To ensure the high adaptability of the detection method, its expected trajectory can be designed accordingly to accommodate different space missions.

[0102] In summary, this large-scale antenna detection method is based on the characteristics of satellite orbits and constructs a closed-loop detection system that integrates physical simulation, mathematical modeling, and real-time control. Using a modified LQR control algorithm combined with gravity compensation and lateral compensation mechanisms, millimeter-level precision control of the dual-satellite trajectory is achieved. Simultaneously, the detection satellite's onboard camera provides real-time feedback of the target satellite's status to the ground control system, forming a data closed loop. Finally, a ground-based semi-physical experimental verification system was used to fully verify the accuracy and rigor of the detection method. The ground-based semi-physical experimental verification system uses an air-floating platform to simulate the microgravity environment of space. Through modularization, the entire verification process is made clear and concise. Motion capture technology is used to synchronously monitor the dual-satellite position and actual trajectory. Experiments show that this detection method can achieve millimeter-level trajectory tracking accuracy in the x / y direction (average error <8mm) and an angular error <2.5°. This verifies the accuracy and robustness of the detection method proposed in this invention under a detection system that simulates the space environment, providing reliable data support for subsequent parameter optimization.

[0103] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A method for detecting a large-scale spatial antenna, characterized in that: include: For the detection satellite and target antenna in the actual space environment, an improved LQR controller is designed to control the detection satellite to perform attitude and orbit control according to the desired trajectory when the target antenna is suspended at the expected position, thereby detecting the target antenna. The design process of the improved LQR controller is as follows: First, the system dynamic equations of the detection satellite and target antenna are constructed, with the detection satellite's measured trajectory as the output variable, the detection satellite's thrust control amount as the control variable, and the detection satellite's preset expected trajectory as the ideal state variable. The difference between the ideal state variable and the output variable is used to construct an error function. Based on the error function and the control variable, a performance index is constructed. The optimal control output corresponds to the minimum performance index. The Hamiltonian function and the canonical equations of the co-state variables and the actual posture are established. The control equation is constructed by taking partial derivatives of the Hamiltonian function on the control variables, thereby obtaining the relationship between the optimal control output and the optimal co-state variables. The solution matrix and feedforward compensation term of the Riccati equation are introduced into the expression of the optimal co-state variables. The relationship between the optimal control output and the solution matrix and feedforward compensation term is obtained through derivation calculation and recursion, thereby solving the optimal control output for trajectory and attitude control of the detection satellite.

2. The method for detecting a large-scale spatial antenna according to claim 1, wherein: The performance indicators are: in, Represents the time from the initial time t0 to the terminal time t f The integral of the error function e(t) = z(t)-y(t) requires the optimal control output u * (t), so that the performance index J is minimized; Q is the state error weight matrix, R is the control input weight matrix; z(t) is the desired trajectory, y(t) is the output variable, and u(t) is the control variable.

3. The method for detecting a large-scale spatial antenna according to claim 1, wherein: The Hamiltonian function is as follows: Where λ(t) refers to the covariate variable and the canonical equation is: Among them, x * (t) is the optimal actual posture, indicating the optimal control output u * The optimal state variable under (t); λ * (t) represents the optimal co-state variable, A is the state transfer matrix, and B is the control input matrix.

4. The method for detecting a large-scale spatial antenna according to claim 1, wherein: The control equation is constructed by taking partial derivatives of the control variables, thereby obtaining the relationship between the optimal control output and the optimal co-state variables; The solution matrix of the Riccati equation and the feedforward compensation term are introduced into the expression of the optimal co-state variable, including: From this we get: u * (t)=-R -1 B T λ * (t) Since the canonical equation is a linear equation, assume that: λ * (t)=P(t)x * (t)-g(t) Where P(t) is the solution matrix of the Riccati equation, and g(t) is the feedforward compensation term.

5. The method for detecting a large-scale spatial antenna according to claim 1, wherein: By * (t) = P(t)x * (t)-g(t) is differentiated and brought into the Hamiltonian function and the canonical equation to obtain: -P(t)A-A T P(t)+P(t)BR -1 B T P(t)-Q=0 g(t)=[A T -P(t)BR -1 B T ] -1 Qz(t) Then the optimal control output for the detection satellite is: u * (t)=-R -1 B T [P(t)x * (t)-g(t)]。 6. The method for detecting a large-scale spatial antenna according to claim 1, wherein: The ground control console plans the trajectory of the detection satellite to obtain the expected trajectory z(t) of the detection satellite; the sensor on board the detection satellite obtains the measurement trajectory y(t) of the detection satellite, and the error between the two is taken as e(t); the control variable u(t) of the detection satellite is obtained as [F x ,F y ,F z ] T , which means the output component of the control force generated by the cold jet thruster in the x, y, and z directions; e(t) and u(t) are input into the improved LQR controller to calculate the optimal control output u * (t) is [F cx ,F cy ,F cz ] T , that is, the thrust components applied by the cold jet propulsion in the x, y, and z directions; using the optimal control output u * (t) Adjust the position and attitude information of the entire detection satellite relative to the target antenna to realize the trajectory control of the detection satellite; during the flyby observation process, the onboard camera on the detection satellite captures the surface image of the target antenna in real time, which is then encoded and transmitted to the ground control console through the communication module. The ground end decodes the image and analyzes the deformation and displacement parameters of the target antenna.

7. A ground semi-physical experimental verification system, characterized in that: include: Ground measurement system, air flotation simulation system, ground control system, detection satellite simulator (4) and target antenna simulator (5), wherein: The ground measurement system is used to determine the real-time trajectory of the detection satellite simulator (4) and the target antenna simulator (5); the air flotation simulation system is used to simulate the actual space environment and provide operation support for the detection satellite simulator (4) and the target antenna simulator (5); the ground control system is used to control the target antenna simulator (5), plan the expected trajectory of the detection satellite simulator (4), control the trajectory of the detection satellite simulator (4) using an improved LQR controller, receive observation data of the detection satellite simulator (4) on the target antenna simulator (5) and perform data analysis; the detection satellite simulator (4) and the target antenna simulator (5) are respectively used to simulate the detection satellite and the target antenna in the actual space environment.

8. The ground-based semi-physical experiment verification system according to claim 7, characterized in that: The ground measurement system includes a support frame (2) arranged around the air flotation simulation system, and a plurality of motion capture cameras (1) are mounted on the support frame (2) via a pan / tilt platform (6); the motion capture cameras (1) capture the measurement trajectory of the detection satellite simulator (4) in real time; The air-floating simulation system comprises an air-floating platform (3), on which a detection satellite simulator (4) and a target antenna simulator (5) are placed. The air-floating platform (3) provides a frictionless environment and multi-degree-of-freedom motion conditions for the operation of the detection satellite simulator (4) and the target antenna simulator (5).

9. The ground-based physical-in-the-loop experiment verification system according to claim 7, characterized in that: The structures of the detection satellite simulator (4) and the target antenna simulator (5) are basically the same, and both include a satellite shell (8), a cold jet propulsion unit (10), an industrial computer control card (11), a gas storage bottle (12), a gas foot (13), a battery (14), a check valve (15), and a high-pressure inflation valve (16), wherein the gas foot (13) and the cold jet propulsion unit (10) are controlled by the industrial computer control card (11), and the industrial computer control card (11) realizes information interaction with a ground measurement system through a wireless module; the cold jet propulsion unit (10) is installed in the satellite shell (8) and is used to generate a three-axis output component of a control force; The air foot (13) is arranged at the bottom of the satellite shell (8) and is used to cooperate with the air floating platform (3) to generate suspension; through the cooperation of the cold jet propulsion device (10) and the air foot (13), the motion control and attitude adjustment of the detection satellite simulator (4) and the target antenna simulator (5) are realized; the gas storage bottle (12) is used to provide high-pressure gas supply to the air foot (13), and the high-pressure gas cylinder is used to replenish the high-pressure gas into the gas storage bottle (12) through the check valve (15) and the high-pressure filling valve (16); the battery (14) is used to provide power for the cold jet propulsion device (10), the industrial computer control card (11) and the air foot (13); The unique structure of the target antenna simulator (5) is a satellite antenna (7) arranged on the top of a satellite shell (8) and solar panels (9) arranged on both sides of the satellite shell (8); the unique structure of the detection satellite simulator (4) is a detection camera (17) installed on the top of the satellite shell (8) for acquiring observation data of the target antenna simulator (5).

10. The ground-based physical-in-the-loop experiment verification system according to claim 7, characterized in that: The target antenna simulator (5) receives a control signal from a ground control system, moves on the surface of an air-floating platform (3) through an air foot (13) to reach a designated position for suspension, and serves as a target satellite; the ground control system generates an expected trajectory of a detection satellite simulator (4), captures the measured trajectory of the detection satellite simulator (4) in real time through a motion capture camera (1), inputs the error function of the expected trajectory and the measured trajectory, and the control variable of the detection satellite into an improved LQR controller to calculate an optimal control output, and uses the optimal control output to control the detection satellite simulator (4) so that the detection satellite simulator (4) flies around the target antenna simulator (5); at the same time, observation data of the target antenna simulator (5) is obtained through a detection camera (17) mounted on the detection satellite simulator (4), and transmitted to the ground control system; in the ground control system, the measured trajectory of the detection satellite simulator (4) is compared with the expected trajectory to verify the accuracy of the detection method.

Images