On Autonomous Take-Off of Tethered Rigid Wings in Compact Space for Airborne Wind Energy

Tethered aircraft during the very first instants after autonomous take-off (20 January 2016)

Lorenzo Fagiano Associate Professor of Controls

Politecnico di Milano

Dipartimento di Elettronica, Informazione e Bioingegneria

Piazza Leonardo da Vinci 32 20133 Milano

Italy

lorenzo.fagiano@polimi.it home.deib.polimi.it/fagiano

On Autonomous Take-Off of Tethered Rigid Wings in

Compact Space for Airborne Wind Energy

Lorenzo Fagiano1,2_{, Eric Nguyen-Van}2_{, Felix Rager}2_{, Stephan Schnez}2_{, Christian Ohler}2 1_{Politecnico di Milano,}2_{ABB Switzerland, Corporate Research}

Notwithstanding the significant achievements and con-tinuous improvements made in the last years, one prob-lem that is still open for most Airborne Wind Energy sys-tems is the aircraft’s capability to take-off autonomously in compact space without large extra-costs, e.g. due to additional required equipments. This is, in turn, a pre-requisite to achieve long-term fully autonomous tests, which would allow the community to ultimately assess the energy conversion efficiency and the capability of these systems to withstand a large amount of operational hours. 0 5 10 15 20 25 30 35 40 45 50 0 10 20 30 40 50 60 Time (s) A lt it u d e (m )

Experimental results of 14 overlayed tests. Course of the aircraft al-titude.

In a recent research activity carried out at ABB Corpo-rate Research, we delivered a small-scale experimental demonstration of a linear take-off approach, in which a ground station is augmented with a linear motion system to accelerate a motorized glider to take-off speed. The experimental results show that a fully autonomous take-off can be realized in very compact space, with a rather small additional power on the ground station to acceler-ate the aircraft. In this presentation, we will provide an overview of the adopted solutions (hardware and soft-ware) and we will present and comment the obtained ex-perimental results. The presented material has been re-cently published in peer-reviewed journals, see [1-3]. A movie of the tests is also available on-line [4].

References:

[1] L. Fagiano and S. Schnez. On the take-off of airborne wind en-ergy systems based on rigid wings. Renewable Enen-ergy, 107:473ś488, 2017.

[2] L. Fagiano et al., Autonomous take off and flight of a tethered aircraft for airborne wind energy. IEEE Trans. on Contr. Sys. Tech.,

In press, 2017. DOI:10.1109/TCST.2017.2661825

[3] L. Fagiano et al., A small-scale prototype to study the take-off of tethered rigid aircrafts for airborne wind energy. IEEE/ASME Trans.

on Mechatronics, 2017. DOI:10.1109/TMECH.2017.2698405

[4] L. Fagiano et al., Autonomous tethered takeoff and

flight for airborne wind energy ś video. March 2016.

https://www.youtube.com/watch?v=UPiTiHPXciE