Wind Tunnel Testing Active Gust Load Alleviation of a Flexible Wing

Abstract

Increasing efficiency is at the core of next generation aircraft development. Aerodynamics can be improved by high aspect ratio wings, but as these wings are more susceptible to loads from gusts and maneuvers, structural weight might increase. Active load control enables the use of high aspect ratio wings while maintaining a relatively low structural weight. To enhance the technology readiness of such secondary flight control functions, experiments are indispensable. This paper describes the wind tunnel testing of a gust load alleviation controller on a flexible swept wing, equipped with multiple trailing edge flaps and acceleration sensors. Disturbances are injected by a gust generator located upstream of the model. The complete process leading up to the active control experiment is outlined: the simulation model used for controller development, the experimental identification of the system and updating of said model, the controller design, and the validation in the wind tunnel. µ-synthesis robust control is used, achieving the best possible performance with respect to the uncertainties in the system. The robust controller achieves a significant load reduction of up to 80% in the wind tunnel tests.