Abstract
In this paper an ℋ∞ control algorithm is applied to design a feedback system for active wing/store flutter suppression. A two degree-of-freedom model of a typical section of an airfoil with an external store in incompressible flow is used for analysis. A state space representation is obtained by using a second order rational approximation of the complex Theodorsen function. The active suppression concept is based on the classical decoupler pylon technique that involves the use of passive soft spring-damper elements to decouple the wing torsion mode from the store pitch inertia effects. The current approach proposes to use a piezo wafer strut as an active device to desensitize the wing from store pitch effects and to eventually aid in increasing the flutter speed. Due to some modeling simplifications made in the analysis, a controller design is attempted that yields a closed-loop system that is robust in the face of unstructured uncertainties without sacrificing the nominal performance. A mixed-sensitivity problem in ℋ∞ control theory is solved where the issues of robust stability and performance measures are explicitly handled.
