Robust Finite-Time Control of an Uncertain Aeroelastic System Using Leading- and Trailing-Edge Flaps

This paper presents a finite-time sliding mode control system for the stabilization of a MIMO nonlinear aeroelastic system using leading-and trailing-edge control surfaces. The selected two-degree-of-freedom aeroelastic model includes uncertain parameters and gust loads. This wing model exhibits limit cycle oscillations (LCOs) beyond a critical free-stream velocity. The objective is to design a control law for stabilization of the LCOs. A control law is derived for the trajectory tracking of the plunge displacement and pitch angle trajectories. The control law includes a finite-time stabilizing control signal for the system without uncertainties and a discontinuous control signal to nullify the effect of uncertain functions. In the closed-loop system, finite-time stabilization of the state vector to the origin is achieved. Simulation results show that the controller accomplishes suppression of LCOs, despite uncertainties in the system parameters and gust loads.