On Using Drones for the Take-off and Landing Phases of an AWE System

Audrey Schanen PhD Researcher

Grenoble INP

GIPSA-lab, Control System Departement Domaine Universitaire 11 rue des Mathématiques

Grenoble Campus BP 46 38402 Saint-Martin d’Hères France audrey.schanen@gipsa-lab.grenoble-inp.fr www.gipsa-lab.fr

On Using Drones for the Take-off and Landing Phases of an AWE System

GIPSA-Lab, University of Grenoble-Alpes / CNRS / Grenoble INP Modeling, control and optimization of AWE system have

been extensively studied theoretically, in numerical en-vironments and through infield experiments. Despite of these above-mentioned developments, several relevant and urgent aspects have to be addressed for the techni-cal feasibility and commercial success of AWE systems. One of such aspects is the take-off and landing of the air-borne platform, especially for on-ground production sys-tems with rigid airfoils.

In this work we have studied the control design of the take-off and landing of a rigid-wing airborne wind en-ergy system using a multicopter. First a 2D model was developed including the drone and the airborne airfoils. The system is subject to aerodynamic forces but also to the thrust force of the drone. From this model a con-troller was designed using an output feedback lineariza-tion method. The aim is to transform the nonlinear track-ing problem to a linear stabiliztrack-ing problem. Then, an in-termediate linear control law is computed to ensure the asymptotic stability of the tracking error. The position of the drone is controlled thanks to the winch torque and the lateral force of the drone, while the tension in the tether is controlled with the radial force of the drone. A simulation on a specific scenario is performed including a take-off, a disturbance due to the wind and then a land-ing. The obtained results show the efficiency of the pro-posed control policy in simulation environment of a hy-brid tethered system that is composed of a rigid wing at-tached to multicopter drone both atat-tached to on-ground winch where the torque is controlled.

In the near future, we are working on implementing a tether model [2] and test the algorithm in a ROS/Gazebo simulation environment. Meanwhile, a small-scale pro-totype is under development to validate the approach experimentally.

The airborne wind energy system with the drone connected to the on-ground station. All forces acting on the system are shown.

References:

[1] Lorenzo Fagiano and Stephan Schnez. On the take-off of air-borne wind energy systems based on rigid wings. Renewable en-ergy, 107:473ś488, 2017.

[2] Paul Williams. Cable modeling approximations for rapid simula-tion. Journal of guidance, control, and dynamics, 40(7):1779ś1788, 2017.