Design and Experimental Validation of a Damping Augmentation Controller via a Saturated Destabilizing/Stabilizing Approach

Abstract

During the development of aircraft next-generation with high-aspect-ratio and highly flexible wings, lightly damped or even unstable aeroelastic modes may emerge. Active control technologies have the potential to increase the aeroelastic damping of such modes by commanding appropriate flap deflections. To further investigate these techniques, safe experimental studies are essential. The goal of this paper is twofold. Firstly, it defines a method, the so-called saturated destabilizing approach, to artificially destabilize an aeroelastic configuration while enabling its safe testing. Secondly, a damping augmentation controller is synthesized to perform the stabilizing task, namely restoring the stability of the destabilized configuration. The feasibility of the proposed approaches is demonstrated on a scaled, flexible, swept wing equipped with multiple trailing-edge flaps and acceleration sensors. Wind-tunnel tests show that the damping augmentation controller effectively restores the stability of the wing, while the saturated destabilizing approach not only enables controlled destabilization of the wing but also ensures safe testing throughout the entire experimental campaign.