Reduced-Order Dynamic Model of a Morphing Airborne Wind Energy Aircraft

Abstract

Airborne wind energy (AWE) is a power production technique aiming to harvest energy from high-altitude winds through tethered aircraft. In the ground-based power generation concept, the aircraft flies dynamic trajectories at high flight speeds and lift coefficients, thus creating large lift forces. These forces drive a ground-based generator via a tether, thereby producing energy. The tethered aircraft operates over a wide range of wind speeds, with distinct operating modes. Current rigid-wing AWE aircraft adapt to these conditions by using discrete control surfaces. Morphing wings, in contrast, can adjust to the different flight conditions and operating modes by continuously altering their shape, and thus can increase the power production of AWE systems. This paper presents the modeling of a camber-morphing AWE system, focusing in particular on the coupled aeroelastics and flight dynamics of the aircraft and on the reduced-order structural and aerodynamic model of the morphing wing. The resulting framework allows analysis of the entire AWE system consisting of the aircraft, tether, and ground station. Owing to its high computational efficiency, the model enables comparison of different trajectories and flight control strategies, and it permits identification of optimal aerodynamic- and structural-design parameters of morphing AWE wings.