The flight mechanics of rigid wing Airborne Wind Energy Systems (AWESs) is fundamentally different from the one of conventional aircrafts. The presence of the tether largely impacts the system dynamics, making the flying craft to experience forces which can be an order of magnitude larger than those experienced by conventional aircrafts. Moreover, an AWES needs to deal with a sustained yet unpredictable wind, and the ensuing requirements for flight maneuvers in order to achieve prescribed control and power production goals. A way to maximize energy capture while facing disturbances without requiring an excessive contribution from active control is that of suitably designing the AWES craft to feature good flight dynamics characteristics. In this study, a baseline circular flight path is considered, and a steady state condition is defined by modeling all fluctuating dynamic terms over the flight loop as disturbances. In-flight stability is studied by linearizing the equations of motion on this baseline trajectory. In populating a linearized dynamic model, analytical derivatives of external forces are computed by applying well-known aerodynamic theories, allowing for a fast formulation of the linearized problem and for a quantitative understanding of how design parameters influence stability. A complete eigenanalysis of an example tethered system is carried out, showing that a stable-by-design AWES can be obtained and how. With the help of the example, it is shown how conventional aircraft eigenmodes are modified for an AWES and new eigenmodes, typical of AWESs, are introduced and explained. The modeling approach presented in the paper sets the basis for a holistic design of AWES that will follow this work.


    Access

    Download


    Export, share and cite



    Title :

    Flight Stability of Rigid Wing Airborne Wind Energy Systems



    Publication date :

    2021-01-01



    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English


    Classification :

    DDC:    629



    Cascaded Pumping Cycle Control for Rigid Wing Airborne Wind Energy Systems

    Rapp, Sebastian / Schmehl, Roland / Oland, Espen et al. | AIAA | 2019


    AIRBORNE VEHICLE WING AND AIRBORNE VEHICLE'S FLIGHT METHOD

    UOLKER STIVEN P / BEKHZADPUR FORUZAN / OUKS GARI D et al. | European Patent Office | 2021

    Free access

    Semi-Rigid Deployable Wing (SDW)-Advanced Precision Airborne Delivery Systems

    Fisher, J. / Wellman, S. / American Institute of Aeronautics and Astronautics | British Library Conference Proceedings | 1997


    Stabilization of the vertical take-off of a rigid flying wing for an airborne wind energy system

    Fuest, H. / Duda, D. F. / Islam, T. et al. | Springer Verlag | 2021

    Free access

    Stabilization of the vertical take-off of a rigid flying wing for an airborne wind energy system

    Fuest, Hendrik / Duda, Dominik / Islam, Tobias et al. | DataCite | 2021