This study focuses on the disturbance observer design and vibration control problems for a flexible aircraft wing system. The flexible aircraft wing is modeled as a coupled twist-bending infinite dimensional distributed parameter system. The dynamic equations and boundary conditions are described by partial differential equations and ordinary differential equations, respectively. In this paper, an infinite dimensional disturbance observer is proposed to estimate both the boundary disturbances and the distributed spatiotemporally varying disturbances. Considering the coupling between the bending deformation and the twist deformation, a boundary controller is proposed to suppress the vibration and inhibit the adverse effects of external disturbances. By using the proposed disturbance observer and controller, the uniform boundednesss of the closed-loop system is validated through theoretical analysis. Finally, simulation results are carried out to illustrate the effectiveness of the proposed infinite dimensional disturbance observer and boundary controller.
