Observer-based terminal sliding mode control for attitude stabilization of flexible spacecraft with fuel slosh

In this paper, an observer-based terminal sliding mode control approach is proposed and applied to the attitude system of the flexible spacecraft with fuel slosh. The disturbances from the vibration of the flexible appendage and fuel slosh are modelled as derivative-bounded disturbances which can be estimated and rejected by the disturbance-observer-based-control (DOBC). Next, composite controller by combining the DOBC with terminal sliding mode controller (TSMC) is proposed to realize the finite time convergence. Therefore, anti-disturbance and finite time attitude stabilization can be guaranteed by the proposed composite controller. Linear matrix inequality (LMI) -based algorithm is used to compute the observer parameters. Finally, theoretical analysis and simulation results are given to verify the effectiveness of the proposed method.