CN-116520719-B - Method and system suitable for full physical simulation of attitude dynamics of flexible spacecraft

CN116520719BCN 116520719 BCN116520719 BCN 116520719BCN-116520719-B

Abstract

The invention provides a method, a system and a system suitable for full physical simulation of attitude dynamics of a flexible spacecraft, and relates to the technical field of spacecraft dynamics and control, wherein the method comprises the steps of simulating a dynamic environment of the spacecraft during in-orbit flight by adopting a static pressure gas lubrication triaxial air bearing table; the platform balancing weight is increased or decreased to coarsely adjust the platform balance, the mass center of the platform is finely adjusted to the origin by the sliding blocks on the guide rail on the platform, inertia identification is carried out on the platform, triaxial moment of inertia of the air bearing platform is obtained, the scaling factor required by the test is determined, flexible interference moment generated in the air injection process is simulated through the interference simulator, the attitude angle of the platform is measured according to different measuring ranges, and the influence of the interference moment generated by the flexible accessory on the attitude of the spacecraft is analyzed. The invention adopts the flexible disturbance moment generator to simulate the disturbance moment generated by the vibration of the flexible accessory to the spacecraft, can ensure that the mass center of the spacecraft is kept unchanged, avoids the phenomenon of backstop, and can also provide reference for the design and demonstration of the spacecraft attitude control scheme.

Inventors

LV WANG
LU GUOPING
Wang tianye
XIN SIBO

Assignees

上海卫星工程研究所

Dates

Publication Date: 20260508
Application Date: 20220124

Claims (8)

1. A method for full physical simulation of attitude dynamics of a flexible spacecraft, comprising: s1, simulating a dynamic environment of a spacecraft in-orbit flight by adopting a static pressure gas lubrication triaxial air bearing table, and reflecting the dynamic influence of disturbance moment generated by vibration of a flexible accessory on the triaxial attitude of the spacecraft; step S2, increasing and decreasing a counter weight of the table body, roughly adjusting the balance of the table body, adjusting a sliding block on a guide rail on the table, and finely adjusting the mass center of the table body to an origin; s3, carrying out inertia identification on the platform body by adopting angular momentum of the flywheel on the platform and angular velocity information measured by the laser gyroscope to obtain triaxial moment of inertia of the air bearing platform, and determining a scaling factor required by a test; S4, providing a control moment for the air bearing table by adopting a cold air thruster on the table, and simulating a flexible interference moment generated in the air injection process by using an interference simulator; S5, measuring the attitude angle of the platform body by adopting a photoelectric autocollimator, a laser tracker and a laser gyro integral according to different measuring ranges, and analyzing the attitude influence of disturbance moment generated by the flexible accessory on the spacecraft; The kinetic equation for a flexible spacecraft is as follows: Wherein, the Is the moment of inertia matrix of the satellite; Is the attitude angular velocity of the spacecraft, Representing the attitude angular velocity of a spacecraft Is the first derivative of (a); is the angular momentum of the spacecraft actuator, Representing angular momentum of spacecraft actuator Is the first derivative of (a); is a rotational coupling coefficient; Is the modal coordinate of the model of the object, Representing modal coordinates Is a second derivative of (2); Is the external disturbance moment of the space environment; For a static pressure gas lubrication triaxial air bearing table, the kinetic equation is as follows: Wherein, the Is an air floating platform body rotational inertia matrix; is the disturbance moment to the table body, including the flexible disturbance moment And other disturbance moment to the table ; To the upper multiplying coefficient The method comprises the following steps: when taking the proper Make the following Close to The air bearing table is considered to be equivalent to the scaled spacecraft inertia, and at the moment, the angular momentum of the spacecraft actuator is considered to be equivalent to the scaled spacecraft inertia And moment of force Flexible disturbance moment A constant amplitude scaling is required.
2. The method for full physical simulation of attitude dynamics of a flexible spacecraft according to claim 1 is characterized in that the mass center of a platform body is unchanged in the static pressure gas lubrication triaxial air bearing platform test process, and a flexible moment generating device is adopted to simulate the vibration frequency of a flexible accessory and the interference moment of the flexible accessory vibration on the spacecraft.
3. The method for full physical simulation of attitude dynamics of a flexible spacecraft according to claim 1, wherein the method for simulating the flexible disturbance moment in the step S4 specifically comprises: S4.1, measuring and collecting triaxial angular velocity information of a platform body in real time by a laser gyroscope on an air bearing platform, transmitting the information to a moment calculation module, and performing differential processing to obtain angular acceleration as input for resolving flexible interference moment; S4.2, setting model parameters of the flexible accessory, and calculating the magnitude of the flexible disturbance moment in real time; And S4.3, obtaining a rotating speed instruction according to a moment distribution algorithm and transmitting the rotating speed instruction to each large moment flywheel.
4. A method for full physical simulation of attitude dynamics of a flexible spacecraft according to claim 3, wherein the model parameters of the flexible accessory in step S4.2 include rotational coupling coefficient, modal frequency and flexible accessory structure damping, and the equation of attitude dynamics of the flexible spacecraft is as follows: Wherein, the Is the attitude angular velocity of the spacecraft, For the cross-multiplication matrix, there are: Wherein, the For the moment of inertia of the whole star, For the whole star angular momentum, Representing disturbance moment generated by vibration of flexible accessory to spacecraft I.e., the simulated disturbance moment, Other external moments.
5. The method for full physical simulation of attitude dynamics of a flexible spacecraft according to claim 3, wherein the three-axis disturbance moment is obtained by resolving the flexible accessory, and the rotation speed of the inner rotor distributed to each moment flywheel is calculated according to the following formula: in the formula, For each rotational speed of the flywheel, Is an installation matrix of the flywheel on the platform body, In order for the disturbance moment to be flexible, The integral variable t is time, which is the inertia of the inner rotor of the flywheel around the rotating shaft.
6. A method for full physics simulation of attitude dynamics of a flexible spacecraft according to claim 3, wherein the flexible accessory vibration equation is: Wherein, the The modal coordinates are represented as such, And Respectively represent First and second derivatives of (2); Representing the structural damping of the flexible attachment; Represented as a flexible attachment modal frequency diagonal matrix; Representing the attitude angular velocity of a spacecraft Is the first derivative of (a); representing a matrix of rotational coupling coefficients Is a transpose of (2); Substituting the flexible accessory vibration equation The calculation formula of the flexible disturbance moment is as follows: therefore, the spacecraft attitude dynamics equation is equivalent to the rigid spacecraft attitude dynamics equation, namely 。
7. The method for full physical simulation of attitude dynamics of a flexible spacecraft according to claim 1, wherein the disturbance simulator is composed of the following components: The flexible moment generating device comprises a plurality of large moment flywheels and a cold air thruster and is used for outputting flexible moment; The laser gyro angular velocity measuring module is used for measuring the angular velocity of the table body; the wireless communication module is used for calculating the flexible interference moment and downloading the telemetry data on the platform; a high-capacity battery for supplying power to each module of the flexible disturbance moment simulation system; The monitoring module consists of an under-platform industrial personal computer and a monitoring computer and is used for monitoring and displaying the magnitude of the flexible interference moment.
8. The method for full physical simulation of attitude dynamics of a flexible spacecraft according to claim 7, wherein the flexible moment generating device is formed by a plurality of large moment flywheels in a three-orthogonal, one-oblique or multiple-oblique configuration, the flexible moment generating device is fixed on an air floating platform body through a tool support, so that the angular momentum of the flywheels and the angular momentum of the air floating platform are exchanged, and the attitude disturbance moment of the spacecraft with flexible accessories is simulated; The wireless communication module calculates flexible disturbance moment in real time after receiving the angular velocity of the gyroscope, generates a flywheel rotating speed command, and sends the flywheel rotating speed remote control command to each large moment flywheel; The flexible moment generating device, the laser gyro angular velocity measuring module, the wireless communication module and the high-capacity battery are bench modules, the bench modules do not contain fans, and the power device radiates heat through the radiating fins.

Description

Method and system suitable for full physical simulation of attitude dynamics of flexible spacecraft Technical Field The invention relates to the technical field of spacecraft dynamics and control, in particular to a method, a system and a system suitable for full physical simulation of attitude dynamics of a flexible spacecraft. Background Spacecraft in order to meet the richer mission requirements, the configuration of the spacecraft is gradually developed from rigidity to great flexibility. The flexible accessories are various, and comprise an antenna, a solar sailboard, a stretching rod mechanism and the like, wherein for example, a high-orbit satellite with a large-scale film antenna is designed by people, the antenna area reaches hundreds of square meters, a larger solar cell array is needed to be carried on the satellite in order to meet the power supply requirement of high power of load, and the light stretching rod mechanism is used for supporting various detector loads in order to avoid the influence of residual magnetism of a satellite platform on the detector. Vibration of the flexible attachment can seriously affect the pointing accuracy and attitude stability of the spacecraft platform. Particularly, when the spacecraft is required to orbit maneuver or orbit position is kept during orbit control, the orbit control engine is ignited and the thrust direction is eccentric, or the attitude control thruster is used for injecting air, flexible vibration can be excited, so that the attitude of the spacecraft is influenced, and the success or failure of a task can be influenced when serious. For example, in 1990, the U.S. hab telescope causes elastic vibration due to thermal deformation in a shadow area, so that the attitude stability does not reach the index requirement, and the image quality is reduced. The "terrestrial satellite-4" observer in the united states in 1982 was disturbed by the flexible solar panel drive system and did not perform as expected. Therefore, aiming at the requirements of high-precision control and high-stability control of the spacecraft with the flexible part, all-physical experiments must be carried out on the static pressure gas lubrication triaxial air bearing table by each type of spacecraft control system to check whether the spacecraft control system meets the index requirements. If the flexible accessory is directly arranged on the air floating table, the barycenter change caused by the vibration of the flexible accessory can lead the barycenter of the static pressure gas lubrication triaxial air floating table to deviate from the center of the air floating ball bearing, and the phenomenon of falling down can occur. The published literature and published patents focus on the full physical simulation method of the flexible spacecraft on the single-axis air bearing table, and a mature method exists. Li Jisu, mou Xiaogang and Wang Chuntao in the "full physical simulation technical research of large flexible structure satellite" ("System simulation academy" 1995.6) propose a scheme related to simulation test of flexible spacecraft of a single-axis air bearing table, and design a flexible arm installed on a table body as simulation equipment of a flexible device, and provide mathematical simulation results. Zhou Jun and Liu Yingying in the experimental study of active vibration feedback full physical simulation of a spacecraft (vibration, test and diagnosis, volume 28, 1 st period in 2008) propose a scheme for configuring a micro accelerometer at the top end of a flexible sailboard of a full physical simulation system and measuring vibration at the micro accelerometer. The invention discloses a test method for simulating three-axis attitude coupling motion of a flexible satellite by adopting a single-axis air bearing table, which comprises the following steps of 1, simulating X-axis rigid main body motion of the flexible satellite to obtain X-direction attitude information of the flexible satellite, 2, constructing the flexible satellite, simulating Y-direction and Z-direction attitude motion of the flexible satellite, establishing and resolving a vibration dynamics model and a space environment interference moment model of a flexible accessory, 3, calculating Y-direction attitude information of the flexible satellite, Z-direction attitude information of the flexible satellite, coupling moment of the flexible accessory and space environment interference moment, 4, controlling an executing mechanism and a moment output device by receiving signals to simulate the three-axis attitude motion of the flexible satellite by adopting the single-axis air bearing table, and 5, repeating the steps 1 to 4 to finish the test of the three-axis attitude coupling motion of the flexible satellite. The upper part is only suitable for a single-shaft air bearing table, cannot be used for a static pressure air lubrication three-shaft air bearing table, and otherwise has the risk of falling dow