Anti-disturbance Control for Flexible Spacecraft with Time-varying Input Delay

This paper focuses on the anti-disturbance attitude control problem of flexible spacecraft with time-varying input delay. A composite hierarchical control structure is designed by combining delays-dependent H-infinity control with disturbance-observer-based control (DOBC). The proposed composite method not only can compensate the disturbances caused by flexible appendages but also can reduce the effects of delay on attitude control. Specially, a decomposition coefficient of delay integral inequality is introduced in the process of solving functional, which may further reduce the design algorithm conservatism. Finally, numerical simulations are used to verify the effectiveness of the proposed method and to show the effects of time delay bound and decomposition coefficient on the closed-loop system performance.