Micro-nano satellite attitude semi-physical simulation experiment demonstration system

Abstract

The invention discloses a micro-nano satellite attitude semi-physical simulation experiment demonstration system, which comprises a control system, a semi-physical simulation machine and a three-axis turntable used for installing a tested micro-nano satellite, and is characterized in that through the cooperation of the control system, the semi-physical simulation machine and the three-axis turntable, a solution-control-feedback-iteration closed-loop process is formed; the specific operation steps of the demonstration system are as follows: S1, initialization and parameter calculation; s2, issuing and driving a target attitude; s3, physical state feedback and closed loop iteration are carried out; through cooperation of the control system, the semi-physical simulation machine and the three-axis rotary table and superposition disturbance of the semi-physical simulation machine, unbiased mapping of physical motion-digital model-space environment is realized, attitude dynamic characteristics of a micro-nano satellite in a real space can be reproduced, simulation fidelity is greatly improved, and the simulation precision of the micro-nano satellite is greatly improved. And the high-precision micro-nano satellite attitude simulation requirement is met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of satellite attitude simulation experiment, in particular to a micro-nano satellite attitude semi-physical simulation experiment demonstration system. BACKGROUND

[0002] Micro-nano satellites are widely used in the fields of communication relay, earth observation and scientific experiments due to their small size, low cost and flexible deployment. The attitude control accuracy of the micro-nano satellites directly determines the success or failure of the mission. For example, the high-resolution imaging task requires an attitude stability better than 0.01°, and the orbit maneuvering task needs to correct the attitude deviation to within 0.1° in real time. As a key means for verifying the attitude control algorithm, the ground semi-physical simulation can simulate the attitude dynamics in the space environment through the linkage of "digital model + physical execution" before launch, thereby reducing the on-orbit risk. Therefore, the ground semi-physical simulation becomes a key link in the development of micro-nano satellites. However, the existing micro-nano satellite attitude semi-physical simulation system has significant limitations in structural design, control accuracy, algorithm coordination and adaptability, and is difficult to meet the high-precision and multi-model simulation requirements. SUMMARY

[0003] The technical problem to be solved by the present application is to provide a micro-nano satellite attitude semi-physical simulation experiment demonstration system, which can meet the high-precision micro-nano satellite attitude simulation requirements.

[0004] To solve the above technical problems, the technical solution adopted by the present application is as follows.

[0005] A micro-nano satellite attitude semi-physical simulation experiment demonstration system, comprising a control system, a semi-physical simulation machine and a three-axis turntable for installing a measured micro-nano satellite. The control system, the semi-physical simulation machine and the three-axis turntable are cooperatively matched to form a closed loop process of calculation-control-feedback-iteration. The specific operation steps of the demonstration system are as follows: S1, initialization and parameter calculation: the semi-physical simulation machine calculates the physical parameters of the measured micro-nano satellite, such as mass distribution and moment of inertia, generates compensation parameters required by the control system, and completes the parameter matching between the physical layer and the algorithm layer; S2, target attitude issuing and driving: based on the simulation requirements, the semi-physical simulation machine generates satellite target attitude instructions and transmits them to the control system for instruction analysis, drives the three-axis turntable to move the measured micro-nano satellite, and simulates the target attitude; S3, physical state feedback and closed loop iteration: when the three-axis turntable moves, the torque, position and speed of the motor in the three-axis turntable are collected in real time, and are transmitted back to the semi-physical simulation machine after being processed by the control system. In this process, the semi-physical simulation machine generates corrected control instructions again based on the feedback data and superimposes disturbance parameters, and then issues the instructions to the control system again to form a closed loop control of "instruction-execution-feedback-correction", thereby simulating the attitude dynamic process in the real space environment.

[0006] The above-mentioned micro-nano satellite attitude semi-physical simulation experiment demonstration system, the control system includes a motor control board, a drive board, and a sampling board. The sampling board is used to sample the motor torque, position and speed; the drive board receives instructions from the motor control board to implement current setting and frequency setting, and then drives the three-axis turntable to move; the motor control board is used to receive instructions from the semi-physical simulation machine and generate corresponding control signals, and summarize the torque, position and speed data obtained by the sampling board and transmit them back to the semi-physical simulation machine.

[0007] A micro-nano satellite attitude semi-physical simulation experimental demonstration system, wherein in step S1 and step S3, the semi-physical simulation machine performs solving and iterative operations based on an internal simulation algorithm, and the simulation algorithm comprises a core mathematical model solving module, an error and control quantity generating module, a disturbance simulation and parameter correction module, and a digital-physical interaction module. The core mathematical model solving module solves attitude dynamics and kinematic equations in real time based on the micro-nano satellite rigid body assumption and three-axis decoupling, providing a digital model benchmark for simulation; the error solving and control quantity generating module calculates attitude and angular velocity errors and generates control torque in combination with PD control logic, providing an instruction benchmark for a three-axis turntable; the disturbance simulation and parameter correction module improves simulation fidelity by introducing disturbance factors and dynamically correcting model parameters; and the digital-physical interaction module forms a closed loop with the physical system via Ethernet.

[0008] A micro-nano satellite attitude semi-physical simulation experiment demonstration system is proposed. The core mathematical model solution module includes attitude dynamics model solution and attitude kinematics model solution. The attitude dynamics model solution is based on the momentum theorem to solve the dynamic characteristics of the angular acceleration of the micro-nano satellite under the action of the control torque. The dynamic equation of formula (1) is used to solve the equation in real time through a numerical integration algorithm to obtain the angular velocity. Dynamic changes: (1) In the formula is the satellite three-axis vector torque ( ), is the angular velocity of the satellite in this system ( ), is the moment of inertia of the micro-nano satellite, represents the cross product, which is calculated using the following formula (2): (2) In formula (2), is the mass of the satellite, are the length, width and height of the satellite respectively; The attitude kinematic model solution uses quaternions to describe the satellite attitude transformation to avoid the Euler angle singularity problem. Based on the quaternion definition and multiplication rules of equations (3)-(5), the evolution law of attitude with angular velocity is solved. The core equation is the kinematic model of equation (4). By solving this equation in real time, the real-time value of the satellite attitude quaternion q is obtained, which is converted into an attitude angle for comparison between the target attitude and the actual attitude. The quaternion is defined as (3) In the formula is the vector part of the quaternion, is the scalar part of the quaternion, is the rotation axis, For around Axis rotation angle; The expression of the satellite attitude kinematic model based on quaternion description is: (4) In the formula Represents the multiplication operation of quaternions, It is defined as formula (5) (5) in Expressed as A skew-symmetric matrix.

[0009] A semi-physical simulation experimental demonstration system for micro-nano satellite attitude is proposed. The error calculation and control quantity generation module includes error quantity calculation and control torque generation. When calculating the error quantity, the deviation between the actual attitude and the target attitude is quantified based on the quaternion attitude error and angular velocity error defined by formula (7). The error calculation result is directly used for control quantity adjustment. The control torque generation adopts the PD control algorithm with a feedforward channel (formula (6)). The control torque T is generated according to the error quantity. The generated T is sent to the control system to drive the three-axis turntable to simulate the satellite attitude motion. Among them, the micro-nano satellite attitude controller with feedforward channel can be designed as (6) The micro-nano satellite attitude error term defined by quaternion can be expressed as (7) In the formula is the expected quaternion, is the desired angular velocity.

[0010] A semi-physical simulation experimental demonstration system for micro-nano satellite attitude. The disturbance simulation and parameter correction module includes space disturbance simulation and model parameter adaptive correction. The space disturbance simulation can superimpose typical space disturbances including external disturbances and internal disturbances in real time. The disturbance term is realized by modifying the dynamic equation: T总 = T + T 扰动 wherein T 扰动 The synthetic interference torque ensures that the physical turntable movement is closer to the real satellite working condition; the model parameter adaptive correction is combined with the physical feedback data of the three-axis turntable to correct the simulation model parameters in real time.

[0011] The digital-physical interaction module includes data receiving and fusion and instruction iterative output, the data receiving and fusion receives the physical feedback data uploaded by the motor control system in real time: the actual position, the actual angular velocity ω and the actual motor output torque T of the three-axis turntable, and after filtering the data, the data are fused to the digital model to update the measured values of q and ω; the instruction iterative output is based on the error between the fused measured attitude and the target attitude, and the error solving and control torque generation steps are re-executed to generate the corrected T and are issued to the motor control system.

[0012] The three-axis turntable includes an outer frame, a middle frame and an inner frame, the outer frame has a U-shaped structure, the bottom of the outer frame is supported by a base, and an outer frame turntable is arranged between the outer frame and the base, and an X-axis driving motor for driving the outer frame to rotate is arranged on the outer frame turntable; the middle frame is nested on the inner side of the outer frame, a middle frame turntable is arranged between the middle frame and the outer frame, and a Y-axis driving motor for driving the middle frame to rotate is arranged on the middle frame turntable; the inner frame is nested on the inner side of the middle frame, an inner frame turntable is arranged between the inner frame and the middle frame, and a Z-axis driving motor for driving the inner frame to rotate is arranged on the inner frame turntable; the inner frame is provided with an adjustable clamp for clamping the measured micro-nano satellite.

[0013] The micro-nano satellite attitude semi-physical simulation experiment demonstration system further includes a GUI display host computer capable of monitoring the micro-nano satellite attitude data in real time, and the communication connection between the control system and the semi-physical simulation machine and between the semi-physical simulation machine and the GUI display host computer is established through Ethernet.

[0014] Thanks to the above technical solutions, the technical progress achieved by the present application is as follows.

[0015] The present invention provides a micro-nano satellite attitude semi-physical simulation experiment demonstration system, which forms a closed-loop process of solution-control-feedback-iteration through the coordination of a control system, a semi-physical simulator, and a three-axis turntable, and superimposes disturbances through the semi-physical simulator, thereby realizing the unbiased mapping of "physical motion-digital model-space environment", and can reproduce the attitude dynamic characteristics of micro-nano satellites in real space, greatly improving the simulation fidelity; the three-axis turntable adopts a motor and a harmonic reducer to eliminate the transmission gap, providing a physical basis for the control accuracy, and at the same time cooperates with the disturbance simulation and parameter correction module based on PD control and error solution to generate correction values, and dynamically By compensating for inertia deviation and disturbance, the three form a three-level precision guarantee of "zero transmission gap, zero feedback delay, and zero correction accumulation", ultimately achieving an angle control accuracy of 0.01° (better than the existing technology of 0.1°), and a repeat positioning error of ≤0.005°, meeting the high-precision attitude algorithm verification requirements of micro-nano satellites; and by combining an adjustable fixture in the inner frame, it can be adapted to mainstream micro-nano satellites of different specifications such as 6U (230mm×140mm×340mm), 3U (100mm×100mm×300mm), etc., solving the problem of single adaptation and limited scenarios of traditional equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Fig. 1 Schematic diagram of the specific operation process of the present invention; Fig. 2 It is a structural block diagram of the present invention; Fig. 3 A specific flow chart of the control system of the present invention; Fig. 4 It is a structural schematic diagram of the three-axis turntable of the present invention.

[0017] Among them: 1. outer frame, 2. inner frame, 3. base, 4. outer frame turntable, 5. middle frame turntable, 6. inner frame turntable, 7. upper clamping mechanism, 8. lower clamping mechanism. DETAILED DESCRIPTION

[0018] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] A semi-physical simulation experimental demonstration system for micro-nano satellite attitude, such as Figs. 1 to 4 As shown, it includes a control system, a semi-physical simulator, a three-axis turntable for installing the micro-nano satellite under test, and a GUI display host computer. Communication connections are established between the control system and the semi-physical simulator, as well as between the semi-physical simulator and the GUI display host computer via Ethernet. Through the coordinated cooperation of the control system, the semi-physical simulator, and the three-axis turntable, a closed-loop process of solution-control-feedback-iteration is formed, in which the GUI display host computer can monitor the attitude data of the micro-nano satellite in real time.

[0020] The specific operation steps of the demonstration system are: S1, initialization and parameter solving: the semi-physical simulation machine is used to solve the physical parameters of the measured micro-nano satellite, such as mass distribution and moment of inertia, to generate compensation parameters required by the control system, and to complete the parameter matching of the physical layer and the algorithm layer.

[0021] S2, target attitude issuing and driving: based on simulation requirements, the semi-physical simulation machine generates satellite target attitude instructions (such as expected roll angle, pitch angle, and yaw angle), and transmits them to the control system for instruction analysis, to drive the three-axis turntable to move the measured micro-nano satellite, simulating the target attitude.

[0022] S3, physical state feedback and closed-loop iteration: when the three-axis turntable moves, the torque, position, and speed of the motor in the three-axis turntable are collected in real time, and after being processed by the control system, they are returned to the semi-physical simulation machine. In this process, the semi-physical simulation machine generates corrected control instructions based on the feedback data, superimposes disturbance parameters, and issues them again to the control system to form a closed-loop control of “instruction-execution-feedback-correction”, simulating the attitude dynamic process in the real space environment.

[0023] The control system includes a motor control board card, a drive board card, and a sampling board card. The sampling board card is used to sample the torque, position, and speed of the motor; the drive board card receives the instructions of the motor control board card to realize current setting and frequency setting, and then drives the three-axis turntable to act; and the motor control board card is used to receive the instructions of the semi-physical simulation machine and generate corresponding control signals, and to return the torque, position, and speed data obtained by the sampling board card to the semi-physical simulation machine.

[0024] The internal working process of the control system is as follows: First, the motor control board card receives the control compensation parameters (such as system inertia) and satellite target attitude instructions issued by the semi-physical simulation machine through Ethernet, and generates control signals for the drive board card after analysis.

[0025] Second, the drive board card receives the instructions of the motor control board card to realize current setting and frequency setting, directly drives the three-axis motor to operate, and completes the attitude motion execution.

[0026] During the satellite attitude simulation motion process, the sampling board card undertakes the real-time state feedback function, collects the key physical quantities (including torque, position, and speed) of the three-axis turntable motor through sensors, and transmits the collected data to the motor control board card through a hardware interface, so as to facilitate feedback to the semi-physical simulation machine for algorithm analysis.

[0027] In step S1 and step S3, the operation of solving and participating in iteration of the semi-physical simulation machine is internally realized based on a simulation algorithm, which includes a core mathematical model solving module, an error and control quantity generating module, a disturbance simulation and parameter correction module, and a digital-physical interaction module.

[0028] The core mathematical model solving module is based on the rigid body assumption of the micro-nano satellite and three-axis decoupling, and solves the attitude dynamics and kinematics equations in real time to provide a digital model benchmark for simulation.

[0029] The core mathematical model solving module includes attitude dynamics model solving and attitude kinematics model solving. The attitude dynamics model solving is based on the momentum theorem, and solves the angular acceleration dynamic characteristics of the micro-nano satellite under the action of the control torque. The dynamics equation of formula (1) is used to solve the equation in real time by a numerical integration algorithm to obtain the dynamic change of the angular velocity (1) In formula (1), is the three-axis vector moment of the satellite , is the angular velocity of the satellite in the body system , is the moment of inertia of the micro-nano satellite, represents the cross product, which is calculated by formula (2) as follows: (2) In formula (2), is the mass of the satellite, is the length, width and height of the satellite, respectively.

[0030] The attitude kinematics model solving uses quaternions to describe the satellite attitude transformation to avoid the singularity problem of Euler angles. Based on the quaternion definition and multiplication rules of formulas (3)-(5), the evolution law of the attitude with the angular velocity is solved. The core equation is the kinematics model of formula (4). By solving the equation in real time, the real-time value of the satellite attitude quaternion q is obtained, which is converted into the attitude angle (roll, pitch and yaw) for comparison between the target attitude and the actual attitude. The quaternion is defined as (3) In formula (3), is the vector part of the quaternion, is the scalar part of the quaternion, is the rotation axis, is the rotation angle around the axis.

[0031] The expression of the satellite attitude kinematics model based on the quaternion description is (4)​ wherein denotes the multiplication of quaternions, is defined as formula (5) (5) wherein is defined as skew-symmetric matrix.

[0032] The error solving and control quantity generating module generates control torque by calculating attitude and angular velocity errors in combination with PD control logic to provide instruction reference for the physical execution layer (three-axis turntable).

[0033] The error solving and control quantity generating module includes error quantity solving and control torque generation. In the error quantity solving, the quaternion attitude error and angular velocity error defined based on formula (7) are used to quantify the deviation between the actual attitude and the target attitude, and the error solving result is directly used for control quantity adjustment. The control torque generation adopts a PD control algorithm (formula (6)) with a feedforward channel to generate control torque T according to the error quantity. The generated T is issued to the control system to drive the three-axis turntable to simulate satellite attitude motion. wherein the micro-nano satellite attitude controller with a feedforward channel can be designed as (6) The quaternion-defined micro-nano satellite attitude error term can be expressed as (7) wherein is the expected quaternion, is the expected angular velocity.

[0034] The disturbance simulation and parameter correction module improves simulation fidelity by introducing disturbance factors and dynamically correcting model parameters.

[0035] The disturbance simulation and parameter correction module includes space disturbance simulation and model parameter adaptive correction. The space disturbance simulation can superimpose typical space disturbances including external disturbances and internal disturbances in real time. The disturbance term is realized by correcting the dynamic equation: T 总 =T+T 扰动 , wherein T 扰动 is the combined disturbance torque, ensuring that the physical turntable motion is closer to the real satellite working condition; the model parameter adaptive correction combines the physical feedback data (torque, position, and speed returned by the sampling board) of the three-axis turntable to correct the simulation model parameters in real time.

[0036] Wherein, the external disturbance includes atmospheric resistance moment, solar pressure moment (calculated dynamically according to orbit position), gravity gradient force moment (based on the distance model between satellite centroid and geocenter), the internal disturbance includes sensor measurement noise (modeling white noise, Gaussian noise, superimposed to angular velocity feedback data), actuator hysteresis error (simulate motor response delay).

[0037] The digital-physical interaction module forms a closed loop with the physical system (three-axis turntable, motor control board) through Ethernet.

[0038] The digital-physical interaction module includes data receiving and fusion and instruction iteration output, the data receiving and fusion receives the physical feedback data uploaded by the motor control system in real time: the actual position of the three-axis turntable (corresponding to the satellite attitude angle), the actual measurement of angular velocity ω, the actual measurement of motor output torque T, and after filtering the data (using Kalman filter to suppress noise), the measured values of q and ω are fused to the digital model; the instruction iteration output is based on the error between the fused measured attitude and the target attitude, re-executes the error solving and control torque generation steps to generate the corrected T and issues it to the motor control system.

[0039] The three-axis turntable includes an outer frame 1, a middle frame 2, and an inner frame, the outer frame 1 is in a U-shaped structure, the bottom of the outer frame 1 is supported by a base 3, and an outer frame turntable 4 is arranged between the outer frame 1 and the base 3, and an X-axis drive motor for driving the outer frame 1 to rotate is arranged on the outer frame turntable 4.

[0040] The middle frame 2 is nested inside the outer frame 1, a middle frame turntable 5 is arranged between the middle frame 2 and the outer frame 1, and a Y-axis drive motor for driving the middle frame 2 to rotate is arranged on the middle frame turntable 5.

[0041] The inner frame is nested inside the middle frame 2, an inner frame turntable 6 is arranged between the inner frame and the middle frame 2, and a Z-axis drive motor for driving the inner frame to rotate is arranged on the inner frame turntable 6.

[0042] 23-bit absolute optical encoders, torque sensors and speed sensors are arranged on the X-axis of the outer frame 1, the Y-axis of the middle frame 2 and the Z-axis of the inner frame, respectively, to facilitate detection of the torque, position and speed of the motor shaft, and timely feedback to the hardware-in-the-loop simulator for timely attitude adjustment.

[0043] The X-axis drive motor, Y-axis drive motor and Z-axis drive motor are respectively provided with harmonic reducers to eliminate gaps and improve driving torque, eliminate back error of traditional gear transmission, realize transmission accuracy ≤0.001°, and ensure low-speed stability and high-speed responsiveness.

[0044] The inner frame is provided with an adjustable clamp for clamping the measured micro-nano satellite, the adjustable clamp includes an upper clamping mechanism 7 and a lower clamping mechanism 8, and an anti-skid rubber pad is arranged on the lower clamping mechanism 8 to ensure stable clamping of the measured micro-nano satellite.

[0045] The lower clamping mechanism 8 realizes multi-dimensional size adjustment through a slide rail-locking structure, and can be adapted to different specifications of micro-nano satellites without replacing mechanical parts.

[0046] The application provides a micro-nano satellite attitude semi-physical simulation experiment demonstration system, which cooperates with a control system, a semi-physical simulation machine and a three-axis turntable, superimposes disturbance through the semi-physical simulation machine, forms a closed loop process of solving-controlling-feedback-iteration, realizes unbiased mapping of "physical motion-digital model-space environment", can reproduce the attitude dynamic characteristics of the micro-nano satellite in the real space, and greatly improves the simulation fidelity; the motor and the harmonic reducer are used in the three-axis turntable to eliminate transmission gap, to provide a physical basis for control accuracy, and to cooperate with a disturbance simulation and parameter correction module based on PD control and error solving to generate a correction amount, dynamically compensate inertia deviation and disturbance, and form three levels of accuracy guarantee of "no transmission gap-no feedback delay-no correction accumulation", so that the angle control accuracy reaches 0.01° (better than the prior art 0.1° level), the repeat positioning error is less than or equal to 0.005°, and the high-precision attitude algorithm verification requirement of the micro-nano satellite is met; and through the adjustable clamp matched with the inner frame, different specifications of micro-nano satellites such as mainstream micro-nano satellites of 6U (230mm*140mm*340mm), 3U (100mm*100mm*300mm) and the like can be adapted, and the problem of single adaptation and limited scene of the traditional equipment is solved.

Claims

1. A micro-nano satellite attitude semi-physical simulation experiment demonstration system, characterized by: The system includes a control system, a semi-physical simulator, and a three-axis turntable for mounting the micro-nano satellite under test. Through the coordinated cooperation of the control system, semi-physical simulator, and three-axis turntable, a closed-loop process of solution-control-feedback-iteration is formed. The specific operation steps of the demonstration system are as follows: S1. Initialization and parameter calculation: Use a hardware-in-the-loop simulator to calculate the physical parameters of the micro-nano satellite under test, such as mass distribution and moment of inertia, to generate the compensation parameters required by the control system and complete parameter matching between the physical layer and the algorithm layer. S2. Target attitude issuance and driving: Based on simulation requirements, the semi-physical simulator generates satellite target attitude commands and transmits them to the control system for command analysis. It then drives the three-axis turntable to move the micro-nano satellite under test and simulate the target attitude. S3. Physical state feedback and closed-loop iteration: When the three-axis turntable is in motion, the torque, position, and speed of the motor in the three-axis turntable are collected in real time. After being processed by the control system, they are transmitted back to the semi-physical simulator. During this process, the semi-physical simulator regenerates corrected control instructions based on the feedback data and superimposes the disturbance parameters. The instructions are then sent back to the control system, forming a closed-loop control of "instruction-execution-feedback-correction", simulating the posture dynamic process in a real space environment.

2. The micro-nano satellite attitude semi-physical simulation experiment demonstration system according to claim 1 is characterized by: The control system includes a motor control board, a drive board, and a sampling board, wherein the sampling board is used to sample the motor torque, position, and speed; The drive board receives the instructions from the motor control board to realize the current setting and frequency setting, and then drives the three-axis turntable to move; The motor control board is used to receive instructions from the semi-physical simulation machine and generate corresponding control signals, and summarize the torque, position, and speed data obtained by the sampling board and return them to the semi-physical simulation machine.

3. The micro-nano satellite attitude semi-physical simulation experiment demonstration system according to claim 1 is characterized by: In step S1 and step S3, the operations of the semi-physical simulation machine for solving and participating in iteration are all implemented internally based on the simulation algorithm, and the simulation algorithm includes a core mathematical model solving module, an error and control quantity generation module, a disturbance simulation and parameter correction module, and a digital-physical interaction module. The core mathematical model solving module is based on the rigid body assumption and three-axis decoupling of the micro-nano satellite, and solves the attitude dynamics and kinematic equations in real time to provide a digital model benchmark for the simulation; the error solving and control quantity generation module calculates the attitude and angular velocity errors, combines the PD control logic to generate the control torque, and provides an instruction benchmark for the three-axis turntable; the disturbance simulation and parameter correction module improves the simulation fidelity by introducing disturbance factors and dynamically correcting the model parameters; the digital-physical interaction module forms a closed loop with the physical system through Ethernet.

4. The micro-nano satellite attitude semi-physical simulation experiment demonstration system according to claim 3 is characterized by: The core mathematical model solution module includes attitude dynamics model solution and attitude kinematics model solution. The attitude dynamics model solution is based on the momentum theorem to solve the dynamic characteristics of the angular acceleration of the micro-nano satellite under the control torque. The dynamic equation of formula (1) is used to solve the equation in real time through the numerical integration algorithm to obtain the angular velocity Dynamic changes: (1) In the formula is the satellite three-axis vector torque ( ), is the angular velocity of the satellite in this system ( ), is the moment of inertia of the micro-nano satellite, represents the cross product, which is calculated using the following formula (2): (2) In formula (2), is the mass of the satellite, are the length, width and height of the satellite respectively; The attitude kinematic model solution uses quaternions to describe the satellite attitude transformation to avoid the Euler angle singularity problem. Based on the quaternion definition and multiplication rules of equations (3)-(5), the evolution law of attitude with angular velocity is solved. The core equation is the kinematic model of equation (4). By solving this equation in real time, the real-time value of the satellite attitude quaternion q is obtained, which is converted into an attitude angle for comparison between the target attitude and the actual attitude. The quaternion is defined as (3) In the formula is the vector part of the quaternion, is the scalar part of the quaternion, is the rotation axis, For around Axis rotation angle; The expression of the satellite attitude kinematic model based on quaternion description is: (4) In the formula Represents the multiplication operation of quaternions, It is defined as formula (5) (5) in Expressed as A skew-symmetric matrix.

5. The micro-nano satellite attitude semi-physical simulation experiment demonstration system according to claim 3 is characterized by: The error calculation and control quantity generation module includes error calculation and control torque generation. When calculating the error, the deviation between the actual attitude and the target attitude is quantified based on the quaternion attitude error and angular velocity error defined by formula (7). The error calculation result is directly used for control quantity adjustment. The control torque generation adopts the PD control algorithm with a feedforward channel (formula (6)). The control torque T is generated according to the error. The generated T is sent to the control system to drive the three-axis turntable to simulate the satellite attitude motion. Among them, the micro-nano satellite attitude controller with feedforward channel can be designed as (6) The micro-nano satellite attitude error term defined by quaternion can be expressed as (7) In the formula is the expected quaternion, is the desired angular velocity.

6. The micro-nano satellite attitude semi-physical simulation experiment demonstration system according to claim 3 is characterized by: The disturbance simulation and parameter correction module includes spatial disturbance simulation and model parameter adaptive correction. The spatial disturbance simulation can superimpose typical spatial disturbances including external disturbances and internal disturbances in real time. The disturbance term is realized by modifying the dynamic equation: T 总 =T+T 扰动 , where T 扰动 To synthesize the interference torque and ensure that the physical turntable motion is closer to the actual satellite working conditions; The adaptive correction of model parameters is combined with the physical feedback data of the three-axis turntable to correct the simulation model parameters in real time.

7. The micro-nano satellite attitude semi-physical simulation experiment demonstration system according to claim 3 is characterized by: The digital-physical interaction module includes data reception and fusion and command iteration output. The data reception and fusion receives physical feedback data uploaded by the motor control system in real time: the actual position of the three-axis turntable, the measured angular velocity ω, and the measured motor output torque T. After filtering the data, it is fused into the digital model to update the measured values ​​of q and ω; the command iteration output is based on the error between the measured posture after fusion and the target posture, re-executes the error solution and control torque generation steps, generates a corrected T, and sends it to the motor control system.

8. The micro-nano satellite attitude semi-physical simulation experiment demonstration system according to claim 1 is characterized by: The three-axis turntable comprises an outer frame (1), a middle frame (2), and an inner frame, wherein the outer frame (1) is in a U-shaped structure, the bottom of the outer frame (1) is supported by a base (3), an outer frame turntable (4) is provided between the outer frame (1) and the base (3), and an X-axis driving motor for driving the outer frame (4) to rotate is provided on the outer frame turntable (4); the middle frame (2) is nested inside the outer frame (1), a middle frame turntable (5) is provided between the middle frame (2) and the outer frame (1), and a Y-axis driving motor for driving the middle frame (2) to rotate is provided on the middle frame turntable (5); the inner frame is nested inside the middle frame (2), an inner frame turntable (6) is provided between the inner frame and the middle frame (2), and a Z-axis driving motor for driving the inner frame to rotate is provided on the inner frame turntable (6); and the inner frame is provided with an adjustable fixture for clamping the micro-nano satellite to be measured.

9. The micro-nano satellite attitude semi-physical simulation experiment demonstration system according to claim 1 is characterized by: It also includes a GUI display host computer that can monitor the micro-nano satellite attitude data in real time. Communication connections are established between the control system and the semi-physical simulation machine, as well as between the semi-physical simulation machine and the GUI display host computer via Ethernet.

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