Continuous Robust Control for Two-Dimensional Airfoils with Leading- and Trailing-Edge Flaps

In this paper, a class of multi-input/multi-output aeroelastic systems with unstructured nonlinear uncerta inty is considered. By using leading- and trailing-edge control surface actuations, a continuous robust controller is proposed to suppress the aeroelastic vibrations of a nonlinear wing-section model with plunging and pitching degrees of freedom. Under a mild restriction that the system uncertainties are second-order differentiable, the control design yields a semiglobal asymptotic stability result, leading to rapid suppression of the plunging and pitching motions. Numerical simulation results demonstrate the performance of the multi-input/multi-output continuous robust control toward suppressing aeroelastic vibration and limit cycle oscillations at pre- and postflutter flight speed regimes, even in the presence of bounded unknown external disturbance.