In-flight estimation of the aerodynamic characteristics of a Magnus effect-based airborne wind energy system

Magnus effect-based Airborne wind energy (AWE) systems are a promising yet still unexplored concept for harnessing wind power at high-altitudes. While other aspects of the technology have been recently studied, the problem of obtaining accurate information regarding the aerodynamic behavior of the suspended cylinder as its spin ratio varies remains open. This paper presents an adaptation of an existing estimation strategy based on a constrained Extended Kalman filter (EKF) for the aerodynamic characterization of a small-scale Magnus effect-based AWE prototype. The evaluation is performed on data obtained during wind tunnel experiments, and results indicate that, after minor modifications, the chosen approach can indeed be applied to Magnus effect-based AWE systems. Moreover, provided that the cylinder's angular velocity is available, it can be employed for approximately determining the relationship existing between the aerodynamic coefficients of lift and drag and the spin ratio of the airborne structure.