Morphing technology for gust alleviation: an UAS application

Atmospheric turbulence can significantly affect aircraft missions in terms of aerodynamic loads and vibration. These effects are particularly meaningful for MALE-HALE UAS because of their high aspect ratios and because of their low speed, sometimes comparable with that of the gust itself. Many studies have been conducted to reach the goal of efficient gust alleviation. A viable solution appears the application of morphing technology. However, the design of morphing aircraft is a strongly multidisciplinary effort involving different expertise from structures to aerodynamics and flight control. In this study, a multidisciplinary wing-and-tail morphing strategy is proposed for attaining gust attenuation in UAVs. The strategy is based on the combined use of: i) an automatic detection system that identifies gust direction and entity and ii) an aeroelastic model stemming from the coupling between a high-order structural model that is able to resolve the motion and the strain and stress distributions of wings with complex internal structures and a Vortex Lattice Method (VLM) model that accounts for the aerodynamics of the wing-tail system. The gust alleviation strategy employs the information from the detection system and the aeroelastic model to determine the modifications of the wing and the tail surfaces aimed at contrasting wind effects, reducing induced loads and flight path errors. Numerical results are presented to assess the capability of the framework.