Extended state observer based control of attitude stabilization for flexible spacecraft with solar pressure and slosh disturbances

The satellite in geostationary orbit present many flexibility due to flexible appendages, solar pressure and fuel sloshing in the tanks which they pose great challenges for accurate attitude control. In this paper, an anti-disturbance proportional-derivative (PD) controller is designed to stabilize the attitude while rejecting the effects of flexible vibrations, environmental disturbances, and unmodeled dynamics, whose are assumed as an extended state. This controller comprises two parts, i.e. an extended state observer and a PD controller with feedforward. First, flexible vibrations, with fuel sloshing and environmental disturbances, and unmodeled dynamics are regarded as an extended state which can be estimated by the extended state observer. Then, the estimated extended state can be compensated by feedforward and the attitude can be stabilized by the PD controller. Numerical simulation results are presented to demonstrate the effectiveness of the control scheme.