Method for realizing satellite three-axis attitude control by combining available flywheels with magnetic torquer in case of flywheel underactuation

Abstract

A Method for realizing satellite three-axis attitude control by combining available flywheels with a magnetic torquer in case of flywheel underactuation comprises the following steps: (1) determining a magnetic control matrix Gamma(b) according to a geomagnetic field intensity vector B measured by a magnetometer, and determining a flywheel control matrix Kw according to the actual availability conditions of flywheels; (2) calculating a magnetic electric current command Izk=Kic*Mzk for three-axis attitude control; (3) calculating a magnetic electric current command Ixz=Kic*Mxz for three-axis magnetic unloading; and (4) calculating a magnetic torquer command Ick=Izk+Ixz, wherein when the magnetic torquer performs attitude control according to the magnetic torquer command, the available counteractive flywheels continue to perform attitude control based on a command torque Tc. According to the method, when only any two or even one flywheel is available in a system, the two or one available flywheel is combined with the three-axis magnetic torquer to realize high-precision satellite three-axis attitude control. The method is suitable for long-term earth pointing control or long-term sun pointing control and is also suitable for wide-angle maneuvering control of any attitude of a satellite.

Description

technical field [0001] The invention belongs to the field of spacecraft attitude control and relates to a satellite three-axis attitude control method when the flywheel is under-driven. Background technique [0002] Modern small satellites generally do not carry a jet system, and the reaction flywheel has become the main actuator for high-performance attitude stabilization control and large-angle attitude maneuver control of small satellites. When the average value of the disturbing torque on the satellite is not zero, the angular momentum of the flywheel will accumulate over time, eventually leading to the saturation of the flywheel speed. Therefore, modern small satellites also need to be equipped with a magnetic torque device to realize flywheel unloading. That is, the reaction flywheel is usually used for attitude control, and the magnetic torque device is used to cooperate with the flywheel to complete the unloading of the flywheel. [0003] In the past satellite atti...

AI Technical Summary

Problems solved by technology

When any one or any two flywheels fail, the flywheel system will not be able to provide three-axis attitude control torque, so the attitude control system degenerates into a typical flywheel underactuated control system (the number of control inputs is less than the number of system degrees of freedom) , no longer have three-axis attitude control capability

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