Automatic Take-Off of a Tethered Aircraft for Airborne Wind Energy: Control Design and Experimental Results

Abstract

Abstract A control approach to realize the autonomous take-off of a tethered aircraft is described, and experimental results on a small-scale prototype are presented. The plant comprises a ground station, equipped with a linear motion system and a controlled winch, connected to a tethered rigid aircraft. The linear motion system is used to accelerate the aircraft to take-off speed. The winch controller has to coordinate the tether reeling with the aircraft motion, and the aircraft controller has to stabilize the attitude and carry out a straight-line climbing phase. The experimental tests show that the designed control system is able to achieve successful and repeatable take-off maneuvers in very compact space. This result is relevant for the ongoing development of airborne wind energy systems, which exploit the flight of tethered aircrafts to convert wind energy into electricity.