Satellite ground staring attitude control multi-software joint simulation system and construction method thereof

Abstract

The invention discloses a satellite ground staring attitude control multi-software joint simulation system and a construction method thereof, and belongs to the technical field of computer simulation, and the construction method comprises the steps: 1, constructing an ADAMS-based microsatellite ontology model; 2, constructing a satellite orbit model and an attitude sensor model based on STK; step 3, constructing a torque execution mechanism model based on MATLAB (matrix laboratory) and Simulink; 4, designing an attitude determination algorithm and a control algorithm of a ground staring task simulation model capable of combining a microsatellite body model, a satellite orbit model, an attitude sensor model and a torque execution mechanism model; according to the method, ADAMS, STK and MATLAB are combined to simulate a satellite body, an attitude sensor, a torque execution mechanism and a running orbit, the attitude control task of the satellite is simulated, and the method has the advantages of being good in simulation effect and visual and intuitive in simulation process.

Description

Technical Field

[0001] The present invention relates to the technical field of computer simulation, and in particular to a multi-software joint simulation system for satellite earth gaze attitude control and a construction method thereof. Background Art

[0002] The attitude pointing of a satellite is one of the primary factors that determine satellite applications, and directly affects the design of satellite application payloads and the formulation of satellite application performance indicators. The attitude control system of a satellite is implemented using classical or modern control theory methods based on attitude dynamics, attitude determination, and attitude control modeling. Since the ground does not have the conditions to simulate the actual on-orbit space environment, the use of mathematical simulation and semi-physical simulation to simulate the on-orbit operation state has become a necessary means for the demonstration and evaluation of satellite attitude control systems.

[0003] The mathematical simulation technology of satellite attitude control system has basically matured. For example, with the development of computer technology, the use of digital simulation technology can not only shorten the development cycle of satellites, but also greatly improve the design efficiency. It is an essential technology in the early stage of satellite design. The satellite attitude control system is a key subsystem for satellites to ensure the completion of payload missions. The high-precision simulation of the satellite attitude control system plays a vital role in the design of the attitude control system. However, the current digital simulation is mainly based on one software, such as using STK for scene-level simulation, or using MATLAB to design specific control algorithms for algorithm-level simulation. Or combine the two and use STK to provide a space environment to verify the performance of the MATLAB algorithm.

[0004] Staring imaging refers to the satellite's rapid attitude maneuvers to make the optical axis of the camera fixed on the star always point to the desired ground point, so that the ground scene can be observed and recorded continuously and in real time. It is an emerging satellite earth remote sensing technology in recent years. However, due to the attitude control problem of the satellite when using this technology, the satellite cannot effectively perform staring imaging when in use. Therefore, it is necessary to simulate it on the ground, establish the corresponding satellite body model, torque actuator and star sensor model to simulate and control its motion attitude; and the above-mentioned single simulation software cannot complete the visual simulation of the satellite body, attitude sensor, torque actuator and orbit when in use, so it is impossible to conduct effective joint simulation research on the staring imaging process on the ground.

[0005] In view of the above problems, it is urgent to design a multi-software joint simulation system for satellite ground gaze attitude control and its construction method, so as to further improve the simulation accuracy of satellite attitude control by combining the advantages of different professional software and solve the problems existing in the above-mentioned existing technologies. Summary of the invention

[0006] In view of the above-mentioned problems, the present invention aims to provide a multi-software joint simulation system for satellite earth gaze attitude control and a construction method thereof. The method combines ADAMS+STK+MATLAB to simulate the satellite body, attitude sensor, torque actuator and orbit, and simulates the satellite's attitude control task. The method has the characteristics of good simulation effect, and the simulation process is visualized and intuitive.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] The construction method of the multi-software joint simulation system for satellite ground gaze attitude control includes:

[0009] Step 1: Construct a microsatellite ontology model based on ADAMS;

[0010] Step 2: Build satellite orbit model and attitude sensor model based on STK;

[0011] Step 3: Construct a torque actuator model based on MATLAB and Simulink;

[0012] Step 4: Design an attitude determination algorithm and a control algorithm for the Earth staring mission simulation model that can combine the microsatellite body model, satellite orbit model, attitude sensor model and torque actuator model.

[0013] Preferably, the process of constructing the microsatellite ontology model based on ADAMS described in step 1 includes:

[0014] Step 11: Use Pro / E software to build the appearance of the small satellite body model, generate the corresponding file and import it into ADAMS software, and define the direction of the satellite's body coordinate system; assign the moment of inertia of the small satellite in ADAMS, and set the environment to a zero-gravity environment;

[0015] Step 12: Set up the interface function in ADAMS to define the input and output of the microsatellite model;

[0016] Step 13: Export the built satellite model as a file that can be recognized by MATLAB.

[0017] Preferably, the process of defining the input and output of the microsatellite ontology model in step 12 includes:

[0018] (1) First, the Euler angle variables, angular velocity variables, and control torque variables of the microsatellite body model are created through algebraic equations;

[0019] The satellite's Euler angles are: YAW, PITCH, ROLL, PITCH is the opposite of the pitch angle; the angular velocity functions are: WX, WY, WZ; the control torque variable is input from the outside, so its function is defined as 0;

[0020] (2) The defined Euler angle variables and angular velocity variables are set as the output of the satellite model, and the control torque variables are set as the input of the satellite model.

[0021] Preferably, the process of constructing the satellite orbit model based on STK in step 2 is to perform orbit simulation in a "generate first, then call" manner, specifically including:

[0022] Step 21: First, use STK to generate a mission scenario, which contains the orbit information of the small satellite, and then MATLAB uses the corresponding command to store the orbit data during the entire simulation time in the workspace;

[0023] Step 22: At the beginning of the simulation, the first orbital data is used to set the initial position of the small satellite, and then the orbital data of the next moment is used to update the position of the small satellite in the next cycle. And so on, the position of the small satellite is continuously updated to realize the in-orbit operation of the small satellite.

[0024] Preferably, the process of constructing the torque actuator model based on MATLAB / Simulink described in step 3 includes:

[0025] Step 31: Directly model the flywheel using Simulink;

[0026] Step 32: Modeling the Jet Thruster Using Simulink

[0027] When modeling, the jet thruster is controlled by pulse width modulation. The pulse width modulator and the jet thruster switch use different calculation cycles, and the two are simulated separately. Among them, the pulse width modulator calculates the pulse instruction in the MATLAB command space, and then passes it to Simulink to control the jet thruster switch time, and then outputs the pulse torque to control the satellite.

[0028] Preferably, the implementation process of the posture algorithm determination described in step 4 includes:

[0029] (1) In the MATLAB command space, the satellite attitude determination algorithm and the initial expected attitude of the ground gaze are used to solve the satellite error attitude;

[0030] (2) In the Simulink module, the attitude control algorithm is used to calculate the flywheel output torque, and feedback adjustment is performed through interference observation to achieve rapid adjustment of the satellite in orbit.

[0031] Preferably, the design process of the control algorithm described in step 4 includes:

[0032] (1) In the MATLAB command space, the satellite attitude determination algorithm and the initial expected attitude of the ground gaze are used to solve the satellite error attitude, and the satellite path is planned after the solution;

[0033] (2) In the Simulink module, attitude control is used to calculate the output torque of the jet thruster on the satellite path to achieve high-precision tracking of the satellite attitude.

[0034] A satellite-to-earth gaze attitude control multi-software joint simulation system is established by using a construction method of a satellite-to-earth gaze attitude control multi-software joint simulation system, including a micro-satellite body model, a satellite orbit model, an attitude sensor model, a torque actuator model, and an attitude determination and control computer model;

[0035] The micro-satellite body model is established based on ADAMS and is used to simulate the satellite in staring imaging;

[0036] The satellite orbit model and attitude sensor model are established based on STK. The satellite orbit model is used to simulate the satellite flight orbit in the simulated staring imaging, and the attitude sensor model is used to provide observation vector information when the satellite is flying.

[0037] The torque actuator model is constructed based on MATLAB and Simulink, and is used to receive control signals from the attitude determination and control computer model to control the satellite flight position and attitude;

[0038] The attitude determination and control computer model is used to control the action of the torque actuator model using built-in attitude determination algorithms and control algorithms.

[0039] Preferably, the simulation process of the satellite ground gaze attitude control multi-software joint simulation system includes:

[0040] S1. Use STK to calculate and generate high-precision satellite orbit data and space environment simulation data, and save them in text form to the local computer;

[0041] S2. Using MATLAB to read the above orbital information and store it in the calculation space;

[0042] S2. Use MATLAB to set the position and attitude of the satellite at the first moment in STK;

[0043] S3. Read the attitude sensor information through MATLAB and input it into the satellite attitude determination algorithm;

[0044] S4. Calculate the current satellite attitude through an attitude determination algorithm;

[0045] S5. passing the attitude information to the satellite attitude controller;

[0046] S6. The satellite attitude controller calculates the control torque and converts it into a control signal to drive the actuator to execute;

[0047] S7. Establish a three-dimensional dynamic model of the satellite body in ADAMS;

[0048] S8. Loading the torque output by executing the maneuver to the ADAMS satellite dynamics three-dimensional model;

[0049] S9.ADAMS satellite dynamics model changes attitude and outputs current attitude data in real time to MATLAB;

[0050] S11. Complete a cycle of attitude control process in MATLAB;

[0051] S12. Use MATLAB to read the satellite position data at the next moment and complete the calculation of the next control cycle.

[0052] The beneficial effects of the present invention are as follows: the present invention discloses a satellite ground gaze attitude control multi-software joint simulation system and a construction method thereof. Compared with the prior art, the present invention has the following improvements:

[0053] 1. The present invention designs a multi-software joint simulation system for satellite staring attitude control and a construction method thereof. The method combines ADAMS+STK+MATLAB to design a set of visualized digital simulation system for satellite staring attitude control. The system simulates the satellite's attitude control task by simulating the satellite's body, attitude sensor, torque actuator and orbit, and has a visualization function, making the attitude control and simulation process more intuitive.

[0054] 2. This method uses ADAMS software to establish the dynamic model of the satellite body, which makes it easier to analyze and study the dynamic and kinematic relationship of the complex system, effectively improving the controllability of the dynamic model of the satellite body and the convenience of studying the dynamic and kinematic relationship; this method uses STK software to perform numerical simulation of the attitude sensor, effectively avoiding the problem that the spatial position of the star cannot be accurately given and the space environment is difficult to simulate; it has the advantages of good simulation effect and visual and intuitive simulation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is a flow chart of satellite attitude control of the present invention.

[0056] Figure 2 This is the overall scheme of the digital simulation system of the present invention.

[0057] Figure 3This is a workflow diagram of the joint simulation system of the present invention.

[0058] Figure 4 This is a diagram of satellite angular velocity changes in the present invention.

[0059] Figure 5 A yaw angle variable map is defined for the present invention.

[0060] Figure 6 An input and output diagram of a satellite model is set for the present invention.

[0061] Figure 7 The satellite model output by the present invention is a file diagram recognizable by MATLAB.

[0062] Figure 8 A simulation scene graph is established for the STK of the present invention.

[0063] Fig. 9 A process diagram for establishing a jet thruster model of the present invention.

[0064] Fig.10 This is a flow chart of attitude determination and control during the large-angle maneuvering phase of the present invention.

[0065] Fig.11 This is a flow chart of posture determination and control in the gaze tracking stage of the present invention.

[0066] Fig.12 This is a simulation interface diagram of the digital simulation system of Example 2 of the present invention.

[0067] Fig.13 This is the quaternion diagram of the expected ground gaze posture according to embodiment 2 of the present invention.

[0068] Fig.14 This is a diagram of the expected angular velocity for ground gaze according to embodiment 2 of the present invention.

[0069] Fig.15 This is the quaternion diagram of the actual ground gaze posture according to embodiment 2 of the present invention.

[0070] Fig.16 This is a diagram of the actual angular velocity of staring at the ground according to embodiment 2 of the present invention.

[0071] Fig.17 This is a diagram of the Euler angle error during the entire mission of Example 2 of the present invention.

[0072] Fig.18 This is a diagram of the angular velocity error during the entire mission of Example 2 of the present invention.

[0073] Fig.19 This is a diagram of the Euler angle error during the ground gaze phase of Example 2 of the present invention.

[0074] Fig. 20This is a diagram of the angular velocity error during the ground gaze phase of Example 2 of the present invention.

[0075] Among them: Figure 4 In the figure, Figure (a) is the torque diagram in the x-axis direction, Figure (b) is the angular velocity diagram in the x-axis direction, Figure (c) is the torque diagram in the y-axis direction, Figure (d) is the angular velocity diagram in the y-axis direction, Figure (e) is the torque diagram in the z-axis direction, and Figure (f) is the angular velocity diagram in the z-axis direction.

[0076] exist Fig.12 In the figure, Figure (a) is a diagram of the ground orientation posture, Figure (b) is a diagram of large-angle maneuvering, Figure (c) is a diagram of the early stage of gazing at the target, Figure (d) is a diagram of the middle stage of gazing at the target, and Figure (e) is a diagram of the late stage of gazing at the target. DETAILED DESCRIPTION

[0077] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0078] Embodiment 1: refer to the attached Figure 1-11 The satellite staring attitude control multi-software joint simulation system and its construction method shown in the figure include:

[0079] Step 1: ADAMS / STK / MATLAB joint simulation system design

[0080] Step 1.1: System overall structure design

[0081] The general process of satellite attitude control can be described as follows: the expected attitude is calculated according to the mission, the current attitude of the satellite is obtained through the attitude determination system, and then the difference between the current attitude and the expected attitude is calculated. The attitude controller uses the corresponding attitude control algorithm based on the difference to calculate the control instruction, and transmits the instruction to the torque actuator to output the torque, which acts on the satellite body to change the satellite attitude. The process is as follows: Figure 1 shown.

[0082] Through Figure 1 It can be seen from the satellite attitude control flow chart that in order to simulate satellite attitude control, it is necessary to establish a satellite body model, a torque actuator and a star sensor model, and an attitude determination and control computer model (including attitude determination algorithm, attitude control algorithm, and calculation of attitude difference and other functions);

[0083] (1) In satellite attitude control, the main concern is the dynamic characteristics of the satellite body, so the dynamics of the satellite body are mainly considered. Automatic Dynamic Analysis of Mechanical Systems (ADAMS) studies the dynamics and kinematics relationship of complex systems. It is based on the calculation of multi-body system dynamics and has unique advantages in dynamic modeling. Therefore, the dynamic model of the satellite body is established using ADAMS software in this embodiment.

[0084] (2) In satellite attitude determination, attitude sensors are mainly used to provide observation vector information. It is difficult to model attitude sensors using mathematical formulas. The main reason is that the spatial position of stars cannot be accurately given and the space environment is difficult to simulate. Therefore, the satellite tool kit (STK) software can be used to perform numerical simulation of attitude sensors. STK can also simulate the complex mission environment of satellites.

[0085] The attitude determination and control computer mainly provides attitude determination algorithm, attitude control algorithm and attitude difference calculation functions, so MATLAB / Simulink can be used directly for modeling and simulation.

[0086] Based on the above analysis, this embodiment uses ADAMS, STK, and MATLAB software to design a satellite attitude control digital simulation system. The overall design route is as follows: Figure 2 shown.

[0087] Step 1.2: Design of three software interconnection methods

[0088] In order to realize joint simulation, data exchange is required between the three softwares, and the three softwares need to be interconnected.

[0089] (1) MATLAB and STK communication

[0090] The STK / MATLAB interface provides two-way communication between STK and MATLAB. The STK port is opened in the MATLAB workspace through the Connect module using the TCP / IP protocol. In MATLAB, there are more than 150 interface functions that can perform corresponding operations on STK, and the reports generated by STK can also be returned to MATLAB for use.

[0091] The attitude change of the satellite does not affect the orbit of the satellite. This embodiment adopts the "generate first, call later" method to perform orbit simulation, that is, first use STK to generate a mission scene, which contains the orbit information of the small satellite, and then MATLAB uses the corresponding command to store the orbit data during the entire simulation time in the workspace. At the beginning of the simulation, the first orbit data is used to set the position of the small satellite at the initial moment, and then the orbit data of the next moment is used to update the position of the small satellite in the next cycle. And so on, the position of the small satellite is continuously updated to realize the in-orbit operation of the small satellite. The advantage of this is that when updating the spatial position of the small satellite, the attitude of the small satellite can also be updated at the same time, so that the position and attitude correspond.

[0092] (2) Integration between MATLAB and ADAMS

[0093] The ADAMS / Controls module in ADAMS supports co-simulation analysis with MATLAB. The co-simulation of ADAMS and MATLAB mainly includes the following steps:

[0094] Constructing a prototype model

[0095] The model can be created by ADAMS, or it can be created by 3D modeling software such as Pro / E or Solidworks and then imported into ADAMS;

[0096] Determine the input and output of ADAMS, where input refers to the variables returned from the external control program to ADAMS, that is, the output of the control system; output refers to the variables entering the external control program, that is, the output of the control model;

[0097] Constructing a control system block diagram

[0098] The system is built by MATLAB / Simulink;

[0099] System joint simulation analysis

[0100] The first two steps mentioned above are completed in ADAMS, and then the established model is converted into a Simulink module and imported into MATLAB as part of the control system.

[0101] (3) Simulation system workflow

[0102] After the analysis of the first two steps, both ADAMS and STK can realize interconnection with MATLAB, so MATLAB is considered as the main body of the simulation system. Figure 3 This is the workflow diagram of the joint simulation system. The whole working process is divided into two stages: preparation stage and simulation stage.

[0103] In the preparation stage: STK is needed to establish the mission orbit and attitude sensor of the small satellite. The purpose of establishing the mission orbit is to obtain the orbit data of the small satellite and provide data support for the small satellite position update in the simulation stage; the establishment of the attitude sensor is to prepare for the acquisition of the small satellite attitude data in the simulation stage. ADAMS and Simulink are used to establish the small satellite attitude control system to prepare for the calculation of the control signal.

[0104] In the simulation stage: MATLAB is used as the main body of the system to drive the operation of the simulation system. The whole process is carried out in a serial manner, that is, one software completes the calculation and simulation, passes the obtained data to the next software, and then pauses. The next software starts to run the calculation after receiving the data, passes the obtained data to the next one, and then pauses, and so on to carry out the cycle.

[0105] Among them, the data between MATLAB's workspace and Simulink cannot be transmitted in real time, because MATLAB cannot read the data in the running Simulink system. Usually, Simulink can only pass the data to the workspace after the simulation time has completed. For this reason, this embodiment adopts the "start-pause-step" method to achieve real-time data transmission between MATLAB and Simulink.

[0106] Step 2: Establishment of ground staring task simulation model and algorithm implementation

[0107] Step 2.11: Construction of microsatellite body model based on ADAMS

[0108] (1) The appearance of the satellite model was created using Pro / E software, and the corresponding files were imported into ADAMS software after being generated. At the same time, the direction of the satellite's body coordinate system was defined; the moment of inertia of the microsatellite was assigned in ADAMS. Since the satellite is in a space environment, the environment is set to a zero-gravity environment.

[0109] After the model is established, a simple simulation can be performed in ADAMS to verify whether the small satellite model conforms to the actual situation. A torque of 0.4 Nm is applied to the x-axis, y-axis, and z-axis of the satellite coordinate system to observe the change in the satellite angular velocity. The results are as follows: Figure 4 shown.

[0110] from Figure 4 It can be seen that the satellite's angular velocity in the three-axis direction increases in direct proportion in the first 5 seconds, and the angular acceleration is a constant value, indicating that the satellite is subject to a constant torque in this direction; the satellite's angular velocity remains unchanged from 5 to 10 seconds, and the angular acceleration is 0, indicating that there is no torque acting on the satellite in this direction. The experimental results are consistent with the actual situation, indicating that the model is established correctly.

[0111] Step 2.12: In order to realize the combination of the microsatellite body and the control system, it is necessary to set up the interface function in ADAMS, that is, to define the input and output of the model:

[0112] (1) First, create Euler angle variables, angular velocity variables, and control torque variables through algebraic equations. The satellite's Euler angles are: YAW, PITCH, ROLL. It is worth noting that PITCH is the opposite of the pitch angle; the angular velocity functions are: WX, WY, WZ; the control torque variable is input from the outside, so its function can be defined as 0; Figure 5 An interface for defining the yaw angle.

[0113] (2) Set the defined Euler angle variables and angular velocity variables as the output of the satellite model, and set the control torque variables as the input of the satellite model, such as Figure 6 shown.

[0114] Step 2.13: At this point, the microsatellite model has been built. In order to realize the joint simulation of ADAMS and MATLAB, the built satellite model is exported as a file that can be recognized by MATLAB, such as Figure 7 As shown in the figure, when Simulink calls the microsatellite model, you only need to enter the saved file name and the "adams_sys" command in the command window.

[0115] Step 2.2: Building satellite orbit and attitude sensor models based on STK

[0116] (1) Although the joint simulation system established according to the first two steps can perform preliminary simulation of attitude control, it cannot reflect the attitude state of the small satellite when it is flying in orbit. Therefore, the simulation made by the above system is not intuitive; at the same time, the output information of the attitude sensor cannot be obtained through simulation. Therefore, this embodiment uses STK software to simulate the orbit of the small satellite, such as Figure 8 shown.

[0117] Since the attitude sensor information obtained by STK (STK can directly output the star vector as the real value of the attitude sensor, and then superimpose noise to generate the simulation value) is an accurate value, it is necessary to introduce a certain error to simulate the actual attitude sensor. For this purpose, the star vector information and angular velocity information can be imported into MATLAB, and the star vector information is added to the star sensor measurement error model to obtain the simulation value of the star sensor; the angular velocity information is substituted into the gyroscope model to obtain the simulation value of the gyroscope.

[0118] Step 2.3: Torque actuator model construction based on MATLAB / Simulink

[0119] Since the satellite's attitude control algorithm is implemented by Simulink, Simulink is mainly used to model the flywheel and jet thruster. The flywheel model is relatively simple and can be modeled directly, so it will not be described in detail here.

[0120] The jet thruster is controlled by pulse width modulation. Since the pulse width modulator and the jet thruster switch use different calculation cycles, they need to be simulated separately. The pulse width modulator calculates the pulse instruction in the MATLAB command space, and then passes it to Simulink to control the jet thruster switch time, and then outputs the pulse torque to control the satellite. The model establishment process is as follows: Fig. 9 shown.

[0121] Step 2.4: Attitude determination and control algorithm implementation

[0122] The attitude determination and control system is mainly implemented by MATLAB / Simulink. According to the characteristics of the attitude determination and control algorithm structure, the attitude determination algorithm can be directly programmed by MATLAB commands, and the attitude control algorithm can be built using Simulink modules. At the same time, combined with the designed path planning method and disturbance observer, as well as the attitude sensor model and torque actuator model, the attitude determination and control system implementation process designed in this embodiment is as follows: Fig.10 , 11 shown.

[0123] Example 2: Refer to the attached Figure 13-20 As shown, the difference from the above-mentioned embodiment 1 is that this embodiment is designed to verify the method described in embodiment 1. The method described in embodiment 1 is used to design a digital simulation system for satellite staring attitude control. The view of multi-software joint simulation is as follows Fig.12 shown.

[0124] From the above STK animation window, we can see that the microsatellite successfully completed the earth staring mission. In order to facilitate the analysis of accuracy, the simulation data is output using MATLAB. The results are as follows Figures 13 to 20 As shown;

[0125] in, Fig.13 , Fig.14 is the expected attitude quaternion and expected angular velocity, where 0-65s is the satellite orientation attitude to the ground, 65-74s is the satellite large-angle maneuvering stage, and 74-390s is the satellite staring and tracking stage to the ground. Fig.15 , Fig.16 This is the actual attitude of the microsatellite. It can be seen that the satellite can complete the entire attitude control task of staring at the ground.

[0126] Fig.17 , Fig.18is the Euler angle error and angular velocity error of the entire attitude control process. It can be seen that the attitude error of the satellite is large in the large-angle rapid maneuvering stage, but the maneuvering time is short, about 9s. In order to facilitate the observation of the attitude error size in the ground gaze stage, the error in the ground gaze stage is plotted separately. Fig.19 and Fig. 20 ,It can be seen that at the point closest to the target point, the algorithm convergence time increases due to the increase in angular velocity, which in turn leads to a larger error;

[0127] from Fig.19 , Fig. 20 It can be seen that the Euler angle errors in the three directions are stable at |δθ|<0.02°, |δψ|<(4×10 -3 )°, after calculation, the deviation angle δα<0.0206°<0.0716°, which meets the conditions for completely stable ground staring imaging. The target point is at the center of the camera field of view, and the imaging accuracy is high;

[0128] The angular velocity errors of the three axes are respectively stable at (1.5×10 -3 )° / s、(5×10 -3 )° / s、(2×10 -3 )° / s, and the angular velocity in the x-axis and y-axis directions is less than 0.0286° / s, which meets the highest angular velocity requirement of camera imaging and has high imaging quality;

[0129] That is, from the above simulation results, the attitude control simulation system construction method proposed in Example 1 of the present invention can fully realize the satellite's ground gaze attitude control simulation, which proves the effectiveness of the method designed in Example 1 of the present invention.

[0130] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for constructing a multi-software joint simulation system for satellite staring attitude control, characterized in that: include Step 1: Construct a microsatellite ontology model based on ADAMS; Step 2: Build satellite orbit model and attitude sensor model based on STK; Step 3: Construct a torque actuator model based on MATLAB and Simulink; Step 4: Design an attitude determination algorithm and a control algorithm for the Earth staring mission simulation model that can combine the microsatellite body model, satellite orbit model, attitude sensor model and torque actuator model.

2. The method for constructing a multi-software joint simulation system for satellite staring attitude control according to claim 1, characterized in that: The construction process of the microsatellite ontology model based on ADAMS described in step 1 includes: Step 11: Use Pro / E software to build the appearance of the small satellite body model, generate the corresponding file and import it into ADAMS software, and define the direction of the satellite's body coordinate system; assign the moment of inertia of the small satellite in ADAMS, and set the environment to a zero-gravity environment; Step 12: Set up the interface function in ADAMS to define the input and output of the microsatellite model; Step 13: Export the built satellite model as a file that can be recognized by MATLAB.

3. The method for constructing a multi-software joint simulation system for satellite staring attitude control according to claim 2, characterized in that: The process of defining the input and output of the microsatellite ontology model described in step 12 includes: (1) First, the Euler angle variables, angular velocity variables, and control torque variables of the microsatellite body model are created through algebraic equations; The satellite's Euler angles are: YAW, PITCH, ROLL, PITCH is the opposite of the pitch angle; the angular velocity functions are: WX, WY, WZ; the control torque variable is input from the outside, so its function is defined as 0; (2) The defined Euler angle variables and angular velocity variables are set as the output of the satellite model, and the control torque variables are set as the input of the satellite model.

4. The method for constructing a multi-software joint simulation system for satellite staring attitude control according to claim 1, characterized in that: The process of building a satellite orbit model based on STK in step 2 is to use the "generate first, then call" method to perform orbit simulation, which specifically includes Step 21: First, use STK to generate a mission scenario, which contains the orbit information of the small satellite, and then MATLAB uses the corresponding command to store the orbit data during the entire simulation time in the workspace; Step 22: At the beginning of the simulation, the first orbital data is used to set the initial position of the small satellite, and then the orbital data of the next moment is used to update the position of the small satellite in the next cycle. And so on, the position of the small satellite is continuously updated to realize the in-orbit operation of the small satellite.

5. The method for constructing a multi-software joint simulation system for satellite staring attitude control according to claim 1, characterized in that: The construction process of the torque actuator model based on MATLAB / Simulink described in step 3 includes: Step 31: Directly model the flywheel using Simulink; Step 32: Modeling the Jet Thruster Using Simulink When modeling, the jet thruster is controlled by pulse width modulation. The pulse width modulator and the jet thruster switch use different calculation cycles, and the two are simulated separately. Among them, the pulse width modulator calculates the pulse instruction in the MATLAB command space, and then passes it to Simulink to control the jet thruster switch time, and then outputs the pulse torque to control the satellite.

6. The method for constructing a multi-software joint simulation system for satellite staring attitude control according to claim 1, characterized in that: The implementation process of the posture algorithm determination described in step 4 includes (1) In the MATLAB command space, the satellite attitude determination algorithm and the initial expected attitude of the ground gaze are used to solve the satellite error attitude; (2) In the Simulink module, the attitude control algorithm is used to calculate the flywheel output torque, and feedback adjustment is performed through interference observation to achieve rapid adjustment of the satellite in orbit.

7. The method for constructing a multi-software joint simulation system for satellite staring attitude control according to claim 1, characterized in that: The design process of the control algorithm described in step 4 includes (1) In the MATLAB command space, the satellite attitude determination algorithm and the initial expected attitude of the ground gaze are used to solve the satellite error attitude, and the satellite path is planned after the solution; (2) In the Simulink module, attitude control is used to calculate the output torque of the jet thruster on the satellite path to achieve high-precision tracking of the satellite attitude.

8. A satellite staring attitude control multi-software joint simulation system established by the construction method as claimed in claim 1, characterized in that: Including micro-satellite body model, satellite orbit model, attitude sensor model, torque actuator model, attitude determination and control computer model; The micro-satellite body model is established based on ADAMS and is used to simulate the satellite in staring imaging; The satellite orbit model and attitude sensor model are established based on STK. The satellite orbit model is used to simulate the satellite flight orbit in the simulated staring imaging, and the attitude sensor model is used to provide observation vector information when the satellite is flying. The torque actuator model is constructed based on MATLAB and Simulink, and is used to receive control signals from the attitude determination and control computer model to control the satellite flight position and attitude; The attitude determination and control computer model is used to control the action of the torque actuator model using built-in attitude determination algorithms and control algorithms.

9. The satellite staring attitude control multi-software joint simulation system as claimed in claim 8, characterized in that: The simulation process of the satellite ground gaze attitude control multi-software joint simulation system includes: S1. Use STK to calculate and generate high-precision satellite orbit data and space environment simulation data, and save them in text form to the local computer; S2. Using MATLAB to read the above orbital information and store it in the calculation space; S2. Use MATLAB to set the position and attitude of the satellite at the first moment in STK; S3. Read the attitude sensor information through MATLAB and input it into the satellite attitude determination algorithm; S4. Calculate the current satellite attitude through an attitude determination algorithm; S5. passing the attitude information to the satellite attitude controller; S6. The satellite attitude controller calculates the control torque and converts it into a control signal to drive the actuator to execute; S7. 在 Establish the satellite body dynamics 3D model in ADAMS; S8. Loading the torque output by executing the maneuver to the ADAMS satellite dynamics three-dimensional model; S9.ADAMS satellite dynamics model changes attitude and outputs current attitude data in real time to MATLAB; S11. Complete a cycle of attitude control process in MATLAB; S12. Use MATLAB to read the satellite position data at the next moment and complete the calculation of the next control cycle.

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