On Modeling, Filtering and Automatic Control of Flexible Tethered Wings for Airborne Wind Energy

An overview of recent results on the control engineering aspects of airborne wind energy is given, for the particular problem of automatic crosswind flight of tethered flexible wings. Mathematical modeling, sensor fusion and control design are presented in a unified framework, hence providing a complete description of an approach to achieve autonomous figure-eight flight patterns. Differently from other existing techniques, the described approach involves few parameters, which can be tuned intuitively, it does not require a measurement of the wind speed, either at ground level or at the wing’s location, but just of the wind direction, and it does not rely on pre-computed flying paths or on complex on-line optimization. The presentation of the methodology is supported by the experimental results obtained with a small-scale prototype.