A Small-Scale Prototype to Study the Take-Off of Tethered Rigid   Aircrafts for Airborne Wind Energy
  The design of a prototype to carry out take-off and flight tests with tethered aircrafts is presented. The system features a ground station equipped with a winch and a linear motion system. The motion of these two components is regulated by an automatic control system, whose goal is to accelerate a tethered aircraft to take-off speed using the linear motion system, while reeling-out the tether from the winch with low pulling force and avoiding entanglement. The mechanical, electrical, measurement and control aspects of the prototype are described in detail. Experimental results with a manually-piloted aircraft are presented, showing a good matching with previous theoretical findings. 
Lorenzo Fagiano, Eric Nguyen-Van, Felix Rager, Stephan Schnez and   Christian Ohler
cs.SY math.OC