Time-domain modeling and control of a wing-section stall flutter

In this paper a nonlinear time-domain aeroservoelastic model is developed to study stall flutter and design flutter suppression control systems. A novel state-space model description enables for both aeroelastic analysis and control design. As a case study, limit cycle oscillations and bifurcation behavior of a NACA 0012 airfoil undergoing stall flutter are investigated. The results agree well with experimental results reported in the literature. Further, to demonstrate the model capability for control design, an output feedback controller is employed to suppress stall flutter and to stabilize the system at different incoming flow speeds to expand the flutter envelope. Closed-loop simulations confirm the improvement of the flutter envelope.