Attitude stabilization of slosh-coupled satellite with flexible appendage

In this paper, a robust control scheme is proposed for flexible satellite attitude stabilization in the presence of multiple disturbances including the disturbances caused by flexible appendages with the sloshing dynamics of the liquid propellant and external disturbances from space environment. A composite control scheme is designed by combining a composite disturbance observer (CDO) with feed-forward controller. First, a CDO is constructed to estimate the lumped disturbances, where the lumped disturbances in the system are equivalent into two parts: a slow varying disturbance and periodic disturbance.  Then a PD controller is adopted to stabilize the system and restrain the residue disturbance. Finally, the simulation results for flexible satellite verify that the proposed method can make the satellite asymptotically stable and demonstrate the effectiveness of the proposed scheme.