Disturbance observer based on controller for roll/yaw attitude stabilization of flexible spacecraft

This study proposed a composite control strategy to realize high-precision attitude stabilization for roll/yaw axes of flexible communication satellites while attenuate the effects of multiple disturbances including elastic vibrations, environmental disturbances, and un-modelled dynamics, etc. The strategy comprises two parts: one is a disturbance observer, and the other is a state feedback controller with feedforward. First, a disturbance observer is designed for multiple disturbances which are modelled as a lumped disturbance with bounded derivative. Then, a state feedback controller is designed to stabilize the roll/yaw attitude after the estimated disturbance is compensated by the feedforward. Numerical simulation results are presented to demonstrate the effectiveness of the control scheme.