Automatic control of tethered wings for airborne wind energy: Design and experimental results

A new approach to control tethered wings for airborne wind energy is described. A fixed length of the lines is considered, and the aim of the control system is to obtain figure-eight crosswind trajectories. The proposed technique is based on the notion of the wing´s “velocity angle” and, in contrast with most existing approaches, it does not require a measurement of the wind speed or of the effective wind at the wing´s location. Moreover, the proposed approach features few parameters, whose effects on the system´s behavior are very intuitive, hence simplifying tuning procedures. Experimental results are presented, obtained by extensively testing the approach with a small-scale prototype.