CN111679592A - A closed-loop semi-physical simulation system and method for spacecraft pursuit and escape game - Google Patents

Abstract

The invention discloses a closed-loop semi-physical simulation system of a spacecraft chase and escape game, which includes a relative measurement simulation subsystem, an on-board GNC simulation subsystem, a closed-loop operation control subsystem and a relative kinematics simulation subsystem. According to the principle of parallel simulation, the relative measurement simulation subsystem, the spaceborne GNC simulation subsystem and the relative kinematics simulation subsystem form a parallel closed-loop operation overall system, which makes the time synchronization relationship in the simulation more coordinated, reduces the time delay, and can The interaction among navigation, guidance and calculation links is reflected through the simulation results; the simulation system introduces real measurement links, guidance links and onboard calculation links, which has higher confidence than pure mathematical simulation; lower cost than physical simulation , the implementation is simple; in addition, the simulation system adopts independent parallel processing for the natural motion of the spacecraft orbit and the game maneuver of pursuit and escape, which makes the simulation more realistic.

Description

A closed-loop semi-physical simulation system and method for spacecraft pursuit and escape game

technical field

The invention relates to the technical field of spacecraft orbit control, in particular to a closed-loop semi-physical simulation system and method of a spacecraft pursuit and escape game.

Background technique

With the development and maturity of the rendezvous and docking technology of the world's major powers, my country's orbiting spacecraft is currently facing the threat of being approached, captured or even manipulated. Especially when both spacecraft can perform autonomous tracking maneuvers or evasive maneuvers, a dynamic game of space pursuit and escape will be formed. In this context, the problem of the spacecraft pursuit and escape game has also become a hot issue in academic research. A series of navigation, guidance and control algorithms that support the spacecraft to carry out the orbital pursuit and escape game have also been developed accordingly, including non-cooperative targets only side by side. Angle-relative navigation algorithm, improved line-of-sight guidance algorithm and differential game guidance algorithm, etc. However, there is still a lack of an experimental system to test the effectiveness of the navigation and guidance algorithms of the spacecraft pursuit and escape game, especially an experimental system that can simulate the entire closed-loop process of the spacecraft pursuit and escape game. Since the problem of spacecraft orbital pursuit and escape is a complex process of integrated communication, navigation, control, calculation and motion, the physical simulation of the pursuit and escape game in the real space environment is costly, risky, and has a long period of time. Therefore, it is urgent to A semi-physical simulation system on the ground simulates the key navigation links, guidance links, on-board calculation links and the closed-loop process formed in the spacecraft pursuit and escape game, and tests the effect of the core algorithms related to the orbital pursuit and escape game. However, no closed-loop hardware-in-the-loop simulation system that can be used for spacecraft pursuit and escape game has been found in the open literature.

SUMMARY OF THE INVENTION

The present invention provides a closed-loop semi-physical simulation system and method for a spacecraft pursuit and escape game, which is used to overcome the defects of the prior art, such as the lack of a method capable of simulating the key points in the spacecraft pursuit and escape game and checking the core algorithm.

In order to achieve the above-mentioned purpose, the present invention proposes a closed-loop semi-physical simulation system of a spacecraft chase and escape game, including:

The relative measurement simulation subsystem is used to simulate the measurement environment and measurement methods in space, collect information on the escape spacecraft model and the tracking spacecraft model, obtain the relative state of the escape spacecraft model and the tracking spacecraft model, and convert the relative state Passed to the onboard GNC simulation subsystem and the closed-loop operation control subsystem; the relative state includes the image, the distance between the escape spacecraft model and the tracking spacecraft model, and the inclination of the escape spacecraft model and the tracking spacecraft model;

The satellite-borne GNC simulation subsystem is used to perform filtering iteration by using a navigation filtering algorithm according to the relative state, to obtain six-dimensional state information including relative position and relative velocity, and use the pursuit and escape game according to the six-dimensional state information. The maneuvering algorithm obtains the control quantities of the tracking spacecraft model and the escape spacecraft model, and converts the control quantities into first control commands and sends them to the closed-loop operation control subsystem;

The closed-loop operation control subsystem is used to integrate the natural motion of the spacecraft orbit according to the relative state to generate a second control command, add the first control command and the second control command to obtain a comprehensive command, and combine the Obtaining the position velocity, attitude angle and attitude angular velocity of the escape spacecraft model and the tracking spacecraft model by calculating the integrated command, and sending the position velocity, attitude angle and attitude angular velocity to the relative kinematics simulation subsystem;

a relative kinematics simulation subsystem for driving the escape spacecraft model and tracking the motion of the spacecraft model according to the position velocity, attitude angle and attitude angular velocity;

The closed-loop operation control subsystem is electrically connected in both directions with the relative measurement simulation subsystem, the on-board GNC simulation subsystem and the relative kinematics simulation subsystem, and the relative measurement simulation subsystem, the satellite The GNC simulation subsystem and the relative kinematics simulation subsystem form a parallel closed-loop running overall system.

In order to achieve the above object, the present invention also proposes a closed-loop semi-physical simulation method for the spacecraft pursuit and escape game, which uses the above-mentioned closed-loop semi-physical simulation system for the spacecraft pursuit and escape game for simulation.

Compared with the prior art, the beneficial effects of the present invention are:

1. The closed-loop semi-physical simulation system of the spacecraft chase and escape game provided by the present invention forms a parallel closed-loop operation overall system according to the principle of parallel simulation, the relative measurement simulation subsystem, the on-board GNC simulation subsystem and the relative kinematics simulation subsystem, The time synchronization relationship in the simulation is more coordinated, the time delay is reduced, and the interaction between the navigation, guidance and calculation links can be reflected through the simulation results.

2. The closed-loop semi-physical simulation system of the spacecraft chase and escape game provided by the present invention introduces real measurement links, guidance links and on-board calculation links, which is relatively pure mathematical simulation and has a higher degree of confidence; relatively physical simulation, low cost and simple implementation .

3. The closed-loop semi-physical simulation system of the spacecraft pursuit and escape game provided by the present invention adopts independent parallel processing for the natural motion of the spacecraft orbit and the maneuvering of the pursuit and escape game. Through such a parallel design, it can be ensured that the spacecraft model has no maneuvering instructions or maneuvers. When there is a time delay in planning, the spacecraft model can maintain a free drift state instead of stopping motion in the simulation, which is consistent with the actual space, making the simulation more realistic.

4. The closed-loop semi-physical simulation system of the spacecraft pursuit and escape game provided by the present invention can be well used to verify the navigation and guidance algorithms of the spacecraft and then carry out the closed-loop semi-physical simulation of the spacecraft pursuit and escape game.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can also be obtained according to the structures shown in these drawings without creative efforts.

Fig. 1 is the overall architecture diagram of the closed-loop semi-physical simulation system of the spacecraft chase and escape game provided by the present invention;

Fig. 2 is the working principle diagram of the closed-loop semi-physical simulation system of the spacecraft chase and escape game provided by the present invention;

Fig. 3 is the closed-loop operation schematic diagram of the closed-loop semi-physical simulation system of the spacecraft chase and escape game provided by the present invention;

Figure 4 is a structural diagram of a nine-degree-of-freedom relative motion platform;

Fig. 5 is the structure diagram of the escape spacecraft model and the tracking spacecraft model adopted by the present invention;

6 is a diagram showing the setting of marker points on the escaping spacecraft model and the tracking spacecraft model in the present invention;

Fig. 7 is the time synchronization relation diagram of the measurement link, the movement link and the planning calculation link in the closed-loop semi-physical simulation system of the spacecraft chase and escape game provided by the present invention;

Fig. 8a is a graph of experimental results of R-bar relative distance filtering in Example 1;

Figure 8b is a graph of the experimental results of R-bar relative velocity filtering in Example 1;

Figure 8c is a graph of the experimental results of V-bar relative distance filtering in Example 1;

Figure 8d is a graph of the experimental results of V-bar relative velocity filtering in Example 1;

Figure 8e is a graph of experimental results of H-bar relative distance filtering in Example 1;

Figure 8f is a graph of experimental results of H-bar relative distance filtering in Example 1;

Fig. 9a is the game experiment result diagram of R-bar relative distance in embodiment 2;

Fig. 9b is the game experiment result diagram of R-bar relative velocity in embodiment 2;

Fig. 9c is the game experiment result diagram of V-bar relative distance in embodiment 2;

Fig. 9d is the game experiment result diagram of V-bar relative velocity in embodiment 2;

Fig. 9e is the game experiment result diagram of H-bar relative distance in embodiment 2;

FIG. 9f is a graph showing the result of a game experiment of the relative velocity of H-bar in Example 2. FIG.

Description of the drawing symbols: 1: X-direction translation motor; 2: Y-direction translation motor; 3: The escape analog end rotates the motor around the Y axis; 4: The tracking analog end rotates the motor around the Y axis; 5: Mark point; 51: Far-field marker point; 52: Near-field marker point.

The realization, functional characteristics and advantages of the present invention will be further described with reference to the accompanying drawings in conjunction with the embodiments.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but must be based on the realization by those of ordinary skill in the art. When the combination of technical solutions is contradictory or cannot be realized, it should be considered that the combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

The invention proposes a closed-loop semi-physical simulation system of a spacecraft pursuit and escape game, which utilizes a nine-degree-of-freedom relative motion platform in a laboratory to drive the escape spacecraft model and the pursuit spacecraft model. The nine-degree-of-freedom relative motion platform is shown in Figure 4. One end is the tracking simulation end, and the tracking spacecraft model is installed on it, which controls the translation of the X-axis of the platform during the relative motion. The maximum speed is 0.5m/s, and the maximum acceleration is 0.05m/s2; the other end is the escape simulation end, on which is installed the escape spacecraft model, which controls the translation of the YOZ plane of the platform in relative motion, with a maximum speed of 0.4m/s and a maximum acceleration of 0.05m/s2 ; In addition, the nine-degree-of-freedom relative motion platform also includes guide rails, motors, communication cables, bases, and the like. The 9-DOF relative motion platform can provide 3-DOF position translation and three-degree-of-freedom attitude rotation for tracking the spacecraft model and escape spacecraft model. The maximum allowable rotation angle is ±30°, and the maximum rotation angular velocity is 5 °/s.

Both the escape spacecraft model and the tracking spacecraft model are shown in Figure 5. Image acquisition equipment and measurement equipment are installed on the escape spacecraft model and the tracking spacecraft model. The installation positions of the image acquisition equipment are respectively the escape spacecraft model. And trace the center axis of the spacecraft model, the center of the bottom line of the front and the center of the side line of the front.

Because when the distance between the tracking spacecraft model and the escape spacecraft model is far, the image of the target in the image acquisition device is a light spot or bright spot; when the distance is short, the target appears in the image acquisition device as a general outline. Therefore, in the present invention, two sets of optical marker points are installed on the escape spacecraft model, which are respectively applicable to the near field and the far field, as shown in FIG. 6 .

The present invention proposes a closed-loop semi-physical simulation system for spacecraft pursuit and escape game, as shown in Figures 1 to 3, including:

(1) The relative measurement simulation subsystem is used to simulate the measurement environment and measurement methods in space to collect information on the escape spacecraft model and the tracking spacecraft model, and obtain the relative state of the escape spacecraft model and the tracking spacecraft model. The relative state is passed to the onboard GNC simulation subsystem and the closed-loop operation control subsystem; the relative state includes the image, the distance between the escape spacecraft model and the tracking spacecraft model, and the inclination of the escape spacecraft model and the tracking spacecraft model. ;

The image is acquired by the image acquisition device set on the spacecraft model;

The distance between the escape spacecraft model and the tracking spacecraft model is acquired by the laser rangefinder set on the spacecraft model;

The inclination angles of the escape spacecraft model and the tracking spacecraft model are acquired by the goniometer set on the spacecraft model.

(2) On-board GNC (guidance navigation and control, navigation, guidance and control) simulation subsystem, which is used to perform filtering iteration by using the navigation filtering algorithm according to the relative state to obtain six-dimensional state information including relative position and relative velocity , according to the six-dimensional state information, use the pursuit-escape game maneuvering algorithm to obtain the control quantities of the tracking spacecraft model and the escape spacecraft model, and convert the control quantities into first control commands and send them to the closed-loop operation control subsystem;

The control quantity is the variation of the position velocity, attitude angle and attitude angular velocity of the tracking spacecraft model and the escape spacecraft model.

The functions of the on-board GNC simulation subsystem are completed on the simulated on-board aircraft, and the calculations in the on-board GNC simulation subsystem are performed on the on-board computer chip.

(3) The closed-loop operation control subsystem is used to integrate the natural motion of the spacecraft orbit according to the relative state to generate a second control command, add the first control command and the second control command to obtain a comprehensive command, and solve the comprehensive command Calculate the position velocity, attitude angle and attitude angular velocity of the escape spacecraft model and the tracking spacecraft model, and send the position velocity, attitude angle and attitude angular velocity to the relative kinematics simulation subsystem;

The solution includes six-degree-of-freedom dynamics solution, attitude kinematics solution and relative motion solution.

(4) The relative kinematics simulation subsystem is used to drive the escape spacecraft model and track the motion of the spacecraft model according to the position velocity, attitude angle and attitude angular velocity;

The relative kinematics simulation subsystem realizes its functions mainly through the nine-degree-of-freedom relative motion platform.

The closed-loop operation control subsystem is electrically connected to the relative measurement and simulation subsystem, the spaceborne GNC simulation subsystem and the relative kinematics simulation subsystem, respectively, and connects the relative measurement and simulation subsystem, the spaceborne GNC simulation subsystem and the relative kinematics simulation subsystem. Form a parallel closed-loop operation of the overall system.

In order to make the time synchronization relationship of each subsystem in the simulation process more coordinated and reduce the time delay, the measurement link, motion link and planning calculation link are parallel to each other when _designing the closed _- loop operation of the overall system. In a frame of , the time synchronization relationship of each link is shown in Figure 7. At the same time, in order to make the motion continuity of the nine-degree-of-freedom relative motion platform better, in the parallel simulation experiment, set the simulation step size as Δt, the measurement period as Δt _z , and the motion period as Δt _m , the three should satisfy the following synchronization Relation: Δt≥Δt _m ＞＞Δt _z , the previous inequality can take the equal sign, in order to ensure that the measurement data is close to the simulation node, the measurement frequency should be high enough relative to the simulation step size.

In one of the embodiments, the closed-loop hardware-in-the-loop simulation system for the spacecraft pursuit and escape game further includes a platform integrated monitoring subsystem, which is used to monitor the entire closed-loop operation system.

The functions of the platform integrated monitoring subsystem are to monitor the simulation data, monitor the video of the test site, and display the simulated motion of the nine-degree-of-freedom relative motion platform. The simulation data monitoring includes the monitoring of the spacecraft model simulation attitude data, the spacecraft model simulation position data monitoring, and the spacecraft model simulation relative position speed monitoring. When an exception or overrun occurs anywhere in the simulation process, the platform integrated monitoring subsystem will send a timely stop command to terminate the simulation process.

In another embodiment, the relative measurement simulation subsystem includes an optical environment simulation module and a measurement module;

The optical environment simulation module is used to simulate the actual space environment including the starry sky background and ground shadow occlusion; for the simulation of the starry sky background, the static scene simulation of the starry sky image is required, and the brightness of the stars is simulated by LED light sources of different powers. For stars with large dynamic changes in position, such as the sun, a movable light source is used for approximate simulation.

The measurement module is used to measure the distance between the escape spacecraft model and the tracking spacecraft model and the inclination angle of the escape spacecraft model and the tracking spacecraft model in real time through the measurement equipment in the environment provided by the optical environment simulation module, and collect in real time through the image acquisition equipment. Images of the escape and pursuit spacecraft models.

In this embodiment, the image acquisition device selects the camera model A5131MG75, the resolution is 1280×1024, the frame rate is 75fps, the optical size is 1/2″, the pixel size is 4.8μm, and the lens model is: MH0620S. The effective focal length is 6mm, the relative aperture is F2.0, the horizontal field of view is 60.8°, the vertical field of view is 42.7°, the distortion rate is less than 0.1%, the minimum object distance is 0.1m, the interface is C-Mount, and the filter interface is M25.5 ×P0.5.

Measurement equipment includes laser rangefinders and inclinometers. The laser rangefinder model is SLD-C30, the range is 0.15m-30m, the measurement accuracy is 2mm, and the output interface is RS485. The model of the inclinometer in the measuring equipment is SCA126V, the measuring angle range is -60° to +60°, the resolution is 0.01, the absolute accuracy is 0.08, the response time is 0.02S, and the output interface is RS485.

In the next embodiment, the on-board GNC simulation subsystem includes an image processing module, a navigation filtering module and a maneuver planning module;

The image processing module is used for processing the image to obtain the angle measurement of the image acquisition device; the angle measurement is the angle when the image acquisition device captures the image.

The navigation filtering module is used to perform filtering iteration by using the navigation filtering algorithm according to the angle measurement and the distance between the escape spacecraft model and the tracking spacecraft model to obtain six-dimensional state information including relative position and relative velocity;

The maneuver planning module is used to obtain the control quantities of the tracking spacecraft model and the escape spacecraft model according to the six-dimensional state information and using the pursuit-escape game maneuvering algorithm, and convert the control quantities into first control instructions and send them to the closed-loop operation control subsystem.

In this embodiment, the calculation in the on-board GNC simulation subsystem is performed on the on-board computer chip. In this embodiment, TMS320C6000 series DSP chips are used for data processing, and the main frequency is 300MHZ. The peripheral devices of the system are integrated on the PCB backplane. Including LCD interface (display terminal), external expansion (DSP expansion slot), program download and online debugging interface (JATG), power interface, network communication interface (Ethnernet) and UART serial port.

In a certain embodiment, the image processing module processes the image, and the specific process of obtaining the angle measurement of the image acquisition device is as follows:

get image;

Extract the grayscale matrix of the image, find the suspected mark point in the grayscale matrix, match the suspected mark point with the actual mark point, and obtain the position of the mark point in the image;

According to the principle of camera imaging, the inverse geometric relationship of the position of the marker point is solved, and the angle measurement of the image acquisition device is obtained. The solution obtains the angle measurement corresponding to the mark point in the image acquisition device in reverse through the corresponding proportional relationship between the image length and width and the camera's field of view angle.

In a certain embodiment, the navigation filtering algorithm loaded in the navigation filtering module is one of Kalman filtering, extended Kalman filtering, unscented Kalman filtering, and filtering algorithms under camera eccentric installation.

In another embodiment, the maneuvering algorithm of the chase-and-flight game loaded in the maneuver planning module is one of a proportional guidance law, an optimal guidance law and a differential game guidance law.

The present invention also proposes a closed-loop semi-physical simulation method for a spacecraft chase and escape game, which uses the above-mentioned closed-loop semi-physical simulation system for a spacecraft chase and escape game for simulation.

In a certain embodiment, the closed-loop hardware-in-the-loop simulation method of the spacecraft chase and escape game includes:

101: According to the similarity principle, set the scaling factor of the simulation system;

102: According to the scaling factor, convert the actual initial position and attitude of the escape spacecraft and the tracking spacecraft into the initial position and attitude of the escape spacecraft model and the tracking spacecraft model in the simulation system, and drive the escape spacecraft model and tracking. The spacecraft model moves to the initial position and attitude;

103: Use the relative measurement simulation subsystem to simulate the measurement environment and measurement methods in space to collect information on the escape spacecraft model and the tracking spacecraft model, and obtain the status information of the escape spacecraft model and the tracking spacecraft model;

According to the state information, the spaceborne GNC simulation subsystem is used to filter and iterate through the navigation filtering algorithm to obtain six-dimensional state information including relative position and relative velocity. The control quantity of the spacecraft model and the escape spacecraft model is converted into the first control command;

The closed-loop operation control subsystem is used to integrate the natural motion of the spacecraft orbit according to the relative state to generate a second control command, add the first control command and the second control command to obtain a comprehensive command, and solve the comprehensive command to obtain an escape spacecraft model and track the position velocity, attitude angle and attitude angular velocity of the spacecraft model;

Use the relative kinematics simulation subsystem to drive the escape spacecraft model and track the motion of the spacecraft model according to the position velocity, attitude angle and attitude angular velocity;

The closed-loop operation control subsystem is used to drive the relative measurement simulation subsystem, the on-board GNC simulation subsystem and the relative kinematics simulation subsystem, so that the escape spacecraft model and the tracking spacecraft model continue to move, so as to realize the closed-loop semi-physical object of the spacecraft pursuit and escape game. simulation.

In a certain embodiment, for step 101, according to the similarity principle, the step of setting the scaling factor of the simulation system includes:

001: In order to realize that the orbital game control ground experiment process is completely similar to the real process in space, and thus achieve the purpose of process reproduction, it is necessary to make the ground verification experimental model and the space prototype system satisfy the time similarity, motion similarity, geometric similarity, force similarity, etc. For similar systems, the similarity criterion maintains the same value at the corresponding point and at the corresponding time. That is, according to the similarity π theorem, the similarity criterion in the measurement process of the relative measurement simulation subsystem and the game process of the relative kinematic simulation subsystem is obtained as:

(π _i ) _p = (π _i ) _m , i = 1,2,3,...,kr (1)

In the formula, π _i is the variable; k is the number of all variables in the system; r is the basic dimension number of the system; the subscript p is the prototype system; the subscript m is the model system;

002: According to the measurement process and the game process, the scaling factor of the variable is defined as the ratio of the model system variable to the prototype system variable:

In the formula, λ _f is the scaling factor of the variable f; the subscript p is the prototype system; the subscript m is the model system;

Through analysis, there are three basic dimensions involved in the measurement process and the game process: time, length and quality.

和

利用λ_t、λ_xn和λ_m，通过相似准则，获得其他变量的缩比因子应满足的关系式：003: Define the scaling factors λ _t , λ _xn and λ _m of the three basic dimensions of time, length and quality according to step 002, namely

and

Using λ _t , λ _xn and λ _m , through the similarity criterion, the relational expressions that the scaling factors of other variables should satisfy are obtained:

In the formula, λ _v , λ _a , λ _ω , λ _α are the scaling factors corresponding to the velocity, acceleration, angular velocity, and angular acceleration, respectively; λ _J is the scaling factor corresponding to the moment of inertia; λ _μ is the gravitational constant corresponding to Scaling factor.

In this certain embodiment, when the scaling factor is actually designed, the scaling factor should satisfy the following design criteria at the same time:

The selection of the scaling factor should make the scaled distance scale within the three-dimensional scale of the relative kinematics simulation subsystem;

The selection of the scaling factor should make the scaled spacecraft maneuverability within the range of the motion capability of the relative kinematics simulation subsystem;

The selection of the scaling factor should meet the needs of the motion display effect of the escape spacecraft model and the tracking spacecraft model.

Example 1

This embodiment is mainly for verifying the effect of the navigation filtering algorithm loaded by the navigation filtering module in the closed-loop hardware-in-the-loop simulation system of the spacecraft chase and escape game provided by the present invention.

In this embodiment, the navigation filtering algorithm loaded by the navigation filtering module is Kalman filtering.

(1) Parameter configuration

Set the scaling factor of the experiment: the length scaling factor is 10000, and the time scaling factor is 1. Tracking spacecraft initial orbital number [a,e,i,ω,Ω,f]=[7020137.0m, 0.0001°, 33°, 18°, 12°, 13.2°], a, e, i, ω, Ω , f are the semi-major axis, eccentricity, orbital inclination, ascending node right ascension, perigee angular distance, true perigee angle, respectively. The initial relative state of the escape spacecraft is: [x,y,z,v _x ,v _y ,v _z ]=[65000m, -1000m, 4000m, -26m/s, 8m/s, -11m/s], x, y, z, v _x , v _y , v _z are respectively x, y, The position and velocity on the z three-axis, the total experiment time is 400s, the experimental simulation step size is 0.5s, and the measurement frequency is 50Hz. The covariance matrix of the initial error is:

(2) Extended Kalman filter to be tested

The state equation and observation equation of the chase-and-flight game system can be written as:

x，y，z为三坐标轴上的相对位置，

为对应的相对速度；观测量z_k＝[r,α,β]^T，r,α,β分别为逃逸航天器模型相对追踪航天器模型的距离、俯仰角、偏航角；k为仿真节点；f(·)和h(·)分别为状态方程和观测方程；u_p(x_k-1)为追踪航天器模型的控制量；u_E(x_k-1)为逃逸航天器模型的控制量；w和v分别为过程噪声和观测噪声。In the formula, the state quantity

x, y, z are the relative positions on the three coordinate axes,

is the corresponding relative velocity; the observed value z _k =[r,α,β] ^T , r,α,β are the distance, pitch angle and yaw angle of the escape spacecraft model relative to the tracking spacecraft model; k is the simulation node ; f(·) and h(·) are the state equation and observation equation, respectively; u _p (x _k-1 ) is the control quantity of the tracking spacecraft model; u _E (x _k-1 ) is the control of the escape spacecraft model quantity; w and v are process noise and observation noise, respectively.

The observation equation satisfies:

x，y，z为三坐标轴上的相对位置。In the formula, r, α, β are the distance, pitch angle and yaw angle of the escape spacecraft model relative to the tracking spacecraft model, respectively,

x, y, z are relative positions on the three coordinate axes.

In order to use the extended Kalman filter in a nonlinear system, it is necessary to approximate the nonlinear observation system. The extended Kalman filter performs Taylor expansion on f and h, and takes the first-order term to obtain the state transition matrix Φ _k and the observation matrix H _k .

In the formula, the meanings of symbols are the same as those of formulas (4) and (5).

Further, the state update equation of the filter can be obtained:

为k-1节点的状态估计值；

为预测的k节点的状态估计值；Φ_k为状态转移矩阵；Q_k为过程噪声协方差矩阵；

为k-1节点的估计误差协方差矩阵；

为预测的k节点的估计误差协方差矩阵；

为预测的k节点的观测值。In the formula,

is the estimated value of the state of the k-1 node;

is the predicted state estimate value of k nodes; Φ _k is the state transition matrix; Q _k is the process noise covariance matrix;

is the estimated error covariance matrix of k-1 nodes;

is the estimated error covariance matrix of the predicted k nodes;

is the observed value of the predicted k nodes.

Then the filtered measurement update equation can be obtained:

为k节点的状态估计值；z_k为k节点的状态估计值；

为k节点的估计误差协方差矩阵；I为单位矩阵；R_k为测量噪声协方差矩阵；K_k为卡尔曼增益；其他符号含义同公式(8)。In the formula, the "+" and "-" signs are respectively after the measurement update and before the update;

is the estimated value of the state of node k; z _k is the estimated value of the state of node k;

is the estimated error covariance matrix of k nodes; I is the identity matrix; R _k is the measurement noise covariance matrix; K _k is the Kalman gain; other symbols have the same meanings as in formula (8).

的值为航天器模型经过滤波处理后的包含相对位置和相对速度在内的六维度状态信息。from the filtering algorithm

The value of is the six-dimensional state information including relative position and relative velocity after filtering processing of the spacecraft model.

(3) Experimental results

The experimental results of the space non-cooperative target navigation filtering are displayed in the three directions of V-bar, H-bar, R-bar, position, velocity, acceleration, and position error, velocity error, and acceleration error, respectively, as shown in Figures 8a-8f. It can be seen from the figure that the Kalman filter (classical filtering algorithm) is used to navigate and filter the space non-cooperative target, and the convergence speed is fast and the precision is high. At the same time, through the error analysis, it can be seen that due to the introduction of the real measurement link, the filtering error presents non-Gaussian characteristics.

Example 2

This embodiment is mainly for verifying the effect of the pursuit and escape game maneuver algorithm loaded by the maneuver planning module in the spacecraft pursuit and escape game closed-loop semi-physical simulation system provided by the present invention.

In this embodiment, the navigation filtering algorithm loaded by the navigation filtering module is a differential game guidance law.

(1) Parameter configuration

Set the scaling factor of the experiment: the length scaling factor is 1000, and the time scaling factor is 20. At the initial moment, the escape spacecraft is on a circular orbit at a height of 400km, and the tracking spacecraft is near the escape spacecraft 5km. The two sides are about to start a game of time. In the virtual moving point LVLH coordinate system, the relative states of the two spacecraft models [x, y, z, v _x , v _y , v _z ]=[250m,-5000m,-200m,0m/s,0m/s, 0m/s], x, y, z, v _x , v _y , v _z are the position and velocity on the x, y, z axes in the LVLH coordinate system, respectively. The configuration of the simulation parameters is shown in Table 1, and the experimental results are shown in Figure 9a to Figure 9f.

Table 1 Parameter configuration of the simulation experiment of the chase and escape game

(2) Guidance law of differential game to be tested

The relative states of the two spacecraft models satisfy the following equations of motion:

In the formula, x(t) is the relative state quantity of the two spacecraft, u _P and u _E are the maneuvering quantities of the tracking spacecraft model and the escape spacecraft model, respectively; A and B are the coefficient matrices in the relative motion equation, assuming the reference The angular velocity of the orbit is ω, then the values of the two satisfy:

The payoff function of the two spacecraft models in the differential game is defined as (the subscripts P and E represent the pursuit spacecraft model and the escape spacecraft model, respectively):

In the formula, Q, R _P , and _RE are the weight coefficients in the payoff function, respectively, and J _P and J _E are the payoff functions of the tracking spacecraft model and the escape spacecraft model, respectively.

According to the maximum and minimum principle, the optimal control law can be obtained:

In the formula, K _P and K _E are the feedback gains of the tracking spacecraft and the escape spacecraft, respectively; P is the Riccati matrix, and the meanings of other symbols are the same as formulas (10) and (11).

In the simulation experiment, the continuous pursuit and flight game system needs to be discretized as:

In the formula, k is the simulation node; the meaning of other symbols is the same as formula (10).

Furthermore, the solution of the optimal control variable can be discretized as:

值是节点k的滤波估计值；其他符号对应公式(12)中变量在节点k的值。In the formula,

value is the filter estimate for node k; other symbols correspond to the value of the variable at node k in equation (12).

(3) Experimental results

It can be seen from Figures 9a to 9f that the semi-physical simulation trajectories are in good agreement with the mathematical simulation trajectories as a whole, and the two spacecraft models reach the intersection state where the relative speed and position are close to zero after 100 seconds. This kind of differential game rendezvous guidance method is highly feasible to carry out orbital pursuit and escape game in space, and can basically achieve the expected game effect. Careful comparison found that the trajectory error on the x-axis (R-bar direction) will be slightly larger than that on the y-axis (V-bar direction) and z-axis (H-bar direction), and the y-axis (V-bar direction) and z The peak value of the velocity curve on the axis (H-bar direction) will be slightly larger than the peak value of the theoretical curve, which also reflects the difference between the results of mathematical simulation and hardware-in-the-loop simulation. Finally, it should be noted that in order to avoid the collision of the two spacecraft models on the nine-degree-of-freedom relative motion platform, a safety distance of 30cm is preset in the simulation, and the game will end when the game reaches the safety distance.

In general, the process of the present invention for verifying the effectiveness of the navigation and guidance algorithms in the process of chasing and escaping a spacecraft is demonstrated through Embodiment 2 and Embodiment 3.

The above descriptions are only the preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. Under the inventive concept of the present invention, the equivalent structural transformations made by the contents of the description and drawings of the present invention, or the direct/indirect application Other related technical fields are included in the scope of patent protection of the present invention.

Claims (10)

1. a closed-loop semi-physical simulation system of a spacecraft chasing and fleeing game, is characterized in that, comprises: The relative measurement simulation subsystem is used to simulate the measurement environment and measurement methods in space, collect information on the escape spacecraft model and the tracking spacecraft model, obtain the relative state of the escape spacecraft model and the tracking spacecraft model, and convert the relative state Passed to the onboard GNC simulation subsystem and the closed-loop operation control subsystem; the relative state includes the image, the distance between the escape spacecraft model and the tracking spacecraft model, and the inclination of the escape spacecraft model and the tracking spacecraft model; The satellite-borne GNC simulation subsystem is used to perform filtering iteration by using a navigation filtering algorithm according to the relative state, to obtain six-dimensional state information including relative position and relative velocity, and use the pursuit and escape game according to the six-dimensional state information. The maneuvering algorithm obtains the control quantities of the tracking spacecraft model and the escape spacecraft model, and converts the control quantities into first control commands and sends them to the closed-loop operation control subsystem; The closed-loop operation control subsystem is used to integrate the natural motion of the spacecraft orbit according to the relative state to generate a second control command, add the first control command and the second control command to obtain a comprehensive command, and combine the Obtaining the position velocity, attitude angle and attitude angular velocity of the escape spacecraft model and the tracking spacecraft model by calculating the integrated command, and sending the position velocity, attitude angle and attitude angular velocity to the relative kinematics simulation subsystem; a relative kinematics simulation subsystem for driving the escape spacecraft model and tracking the movement of the spacecraft model according to the position velocity, attitude angle and attitude angular velocity; The closed-loop operation control subsystem is electrically connected in both directions with the relative measurement simulation subsystem, the on-board GNC simulation subsystem and the relative kinematics simulation subsystem, and the relative measurement simulation subsystem, the satellite The GNC simulation subsystem and the relative kinematics simulation subsystem form a parallel closed-loop running overall system. 2 . The closed-loop hardware-in-the-loop simulation system of the spacecraft chase and escape game according to claim 1 , wherein the simulation system further comprises a platform integrated monitoring subsystem for monitoring the closed-loop operation overall system. 3 . 3. The spacecraft pursuit and escape game closed-loop semi-physical simulation system according to claim 1, wherein the relative measurement simulation subsystem comprises an optical environment simulation module and a measurement module; The optical environment simulation module is used to simulate the actual space environment including starry sky background and ground shadow occlusion; The measurement module is used to measure the distance between the escape spacecraft model and the tracking spacecraft model and the inclination angle of the escape spacecraft model and the tracking spacecraft model in real time through the measurement device under the environment provided by the optical environment simulation module. The acquisition device acquires images of the escape spacecraft model and the tracking spacecraft model in real time. 4. The spacecraft pursuit and escape game closed-loop semi-physical simulation system as claimed in claim 1, wherein the on-board GNC simulation subsystem comprises an image processing module, a navigation filter module and a maneuver planning module; The image processing module is used to process the image to obtain the angle measurement of the image acquisition device; The navigation filtering module is configured to perform filtering iteration by using a navigation filtering algorithm according to the angle measurement and the distance between the escape spacecraft model and the tracking spacecraft model, and obtain a six-dimensional state including relative position and relative velocity. information; The maneuvering planning module is used to obtain the control quantities of the tracking spacecraft model and the escape spacecraft model by using the pursuit and escape game maneuvering algorithm according to the six-dimensional state information, and convert the control quantities into first control instructions and send them to the closed loop. Run the control subsystem. 5. The spacecraft chasing and fleeing game closed-loop semi-physical simulation system as claimed in claim 4, wherein the image processing module processes the image, and the specific process of obtaining the angle measurement of the image acquisition device is: obtain the image; Extracting the grayscale matrix of the image, searching for the suspected mark point in the grayscale matrix, matching the suspected mark point with the actual mark point, and obtaining the position of the mark point in the image; According to the principle of camera imaging, the inverse geometric relationship of the position of the marker point is solved, and the angle measurement of the image acquisition device is obtained. 6. The closed-loop semi-physical simulation system of spacecraft chasing and fleeing game as claimed in claim 4, wherein the navigation filtering algorithm loaded in the navigation filtering module is Kalman filtering, extended Kalman filtering, unscented Kalman filtering and one of the filtering algorithms under the eccentric installation of the camera. 7. The closed-loop semi-physical simulation system of spacecraft pursuit and escape game as claimed in claim 4, characterized in that, the pursuit and escape game maneuver algorithm loaded in the maneuver planning module is proportional guidance law, optimal guidance law and differential strategy One of the guidance laws. 8. A closed-loop semi-physical simulation method for a spacecraft pursuit and escape game, characterized in that, applying the spacecraft pursuit and escape game closed-loop semi-physical simulation system according to any one of claims 1 to 7, and the simulation method comprises: According to the similarity principle, the scaling factor of the simulation system is set; According to the scaling factor, the actual initial positions and attitudes of the escape spacecraft and the tracking spacecraft are converted into the initial positions and attitudes of the escape spacecraft model and the tracking spacecraft model in the simulation system, and the escape spacecraft is driven moving the spacecraft model and tracking the spacecraft model to the initial position and attitude; Use the relative measurement simulation subsystem to simulate the measurement environment and measurement methods in space to collect information on the escape spacecraft model and the tracking spacecraft model, and obtain the state information of the escape spacecraft model and the tracking spacecraft model; According to the state information, the satellite-borne GNC simulation subsystem is used to perform filtering and iteration through the navigation filtering algorithm to obtain six-dimensional state information including relative position and relative velocity. According to the six-dimensional state information, use the pursuit and escape game maneuver algorithm , obtain the control quantity of the tracking spacecraft model and the escape spacecraft model, and convert the control quantity into the first control command; The closed-loop operation control subsystem is used to integrate the natural motion of the spacecraft's orbit according to the relative state to generate a second control command, add the first control command and the second control command to obtain a comprehensive command, and combine the composite command Solve the command to obtain the position velocity, attitude angle and attitude angular velocity of the escape spacecraft model and the tracking spacecraft model; Utilize the relative kinematics simulation subsystem to drive the escape spacecraft model and track the movement of the spacecraft model according to the position velocity, attitude angle and attitude angular velocity; The relative measurement simulation subsystem, the on-board GNC simulation subsystem and the relative kinematics simulation subsystem are driven by the closed-loop operation control subsystem, so that the escape spacecraft model and the tracking spacecraft model continue to move, so as to realize the spacecraft Closed-loop semi-physical simulation of chase and escape game. 9. The closed-loop hardware-in-the-loop simulation method of spacecraft pursuit and escape game as claimed in claim 8, wherein, according to the similarity principle, the step of setting the scaling factor of the simulation system, comprising: According to the similarity π theorem, the similarity criterion in the measurement process of the relative measurement simulation subsystem and the game process of the relative kinematic simulation subsystem is obtained as: (π _i ) _p = (π _i ) _m , i = 1,2,3,...,kr (1) In the formula, π _i is the variable; k is the number of all variables in the system; r is the basic dimension number of the system; the subscript p is the prototype system; the subscript m is the model system; According to the measurement process and the game process, the scaling factor of the variable is defined as the ratio of the model system variable to the prototype system variable:

In the formula, λ _f is the scaling factor of the variable f; the subscript p is the prototype system; the subscript m is the model system; The scaling factor λ _t that defines the three basic dimensions of time, length and mass,

and λ _m , using the λ _t ,

and λ _m , through the similarity criterion, the relational expressions that the scaling factors of other variables should satisfy are obtained:

In the formula, λ _v , λ _a , λ _ω , λ _α are the scaling factors corresponding to the velocity, acceleration, angular velocity, and angular acceleration, respectively; λ _J is the scaling factor corresponding to the moment of inertia; λ _μ is the gravitational constant corresponding to Scaling factor. 10. The closed-loop hardware-in-the-loop simulation method of spacecraft pursuit and escape game as claimed in claim 9, wherein the scaling factor needs to satisfy the following design criteria at the same time: The selection of the scaling factor should make the scaled distance scale within the three-dimensional scale of the relative kinematics simulation subsystem; The selection of the scaling factor should make the scaled spacecraft maneuverability within the range of the motion capability of the relative kinematics simulation subsystem; The selection of the scaling factor should meet the needs of the motion display effect of the escape spacecraft model and the tracking spacecraft model.

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