Two-dimensional active wing/store flutter suppression using H-infinity theory

An active method of decoupling the wing from store pitch inertia effects is presented for the wing/store flutter suppression problem. The proposed active alecoupler pylon involves the use of a piezoceramic wafer strut as an actuator, which acts as a soft spring between the wing and the store. A 2-DOF typical section of an airfoil is used to represent the structural model of an F-16 aircraft wing, and the flutter problem is studied in an incompressible flow regime where the circulatory component of the aero loads is modeled using Jones' approximation to the Theodorsen function. The aerodynamic effects on the store, however, are neglected, and a controller is designed using H-infinity theory to make the closed-loop system robust to such unstructured uncertainties. Under a set of design specifications quantified as weighting functions, a mixed-sensitivity H-infinity optimal control synthesis problem is solved for the design of a controller. Singular-value Bode plots of robust stability and nominal performance measures are used for the analysis of the dosed-loop system. (Author)