Event‐Triggered Anti‐Disturbance Attitude Control for Flexible Spacecraft With Unknown Harmonic Disturbances via Adaptive Disturbance Observer

ABSTRACT This article addresses the attitude control issue subject to unknown harmonic disturbances and inertial uncertainties for flexible spacecraft based on a dynamic event‐triggered mechanism and a T–S fuzzy modeling method. To estimate the flexible modes, a flexible vibration observer is constructed. An auxiliary filter is applied to transform unknown harmonic disturbances into an expression with unknown parameters. Then according to the estimations of unknown parameters, an adaptive disturbance observer is constructed. Additionally, the control scheme based on the dynamic event‐triggered mechanism is designed to guarantee the boundedness of all closed‐loop. Finally, two simulation cases are given for disturbances with single frequency and multiple frequencies to show the feasibility and effectiveness of the proposed control strategy.