Control of Vertical Take Off, Pumping Operation and Vertical Landing of Hybrid Drones for Airborne Wind Energy

Computational flow simulation of a Skypull prototype: streamlines and surface pressure coefficient

Skypull’s AWE system ready for launch (1 December 2018)

Composite photo of a successful test flight of the Skypull system (May 2019) 140

Lorenzo Fagiano

Associate Professor Politecnico di Milano

Dipartimento di Elettronica, Informazione e Bioingegneria

Piazza Leonardo da Vinci 32 20133 Milano

Italy

lorenzo.fagiano@polimi.it www.polimi.it

Control of Vertical Take Off, Pumping Operation and Vertical Landing

of Hybrid Drones for Airborne Wind Energy

Davide Todeschini1_{, Lorenzo Fagiano}1_{, Aldo Cattano}2_{, Claudio Micheli}2 1_{Politecnico di Milano}

2_{Skypull SA} A control design approach for a tethered, hybrid multi-copter/box-wing drone for pumping airborne wind en-ergy is presented. The drone, designed by Skypull SA [1] (see Figure), features four propellers and multiple aerodynamic control surfaces, and can operate either as multi-copter or as an airplane. The goal is to achieve fully autonomous vertical take-off, transition to dynamic flight and pumping operation, and vertical landing. A model-based, hierarchical feedback controller is proposed, with linear inner control loops to stabilize the drone’s attitude, and outer nonlinear loops to obtain the desired flight tra-jectory. A switching strategy is employed to transition from hovering mode (i.e. multi-copter) to dynamic flight mode (i.e. airplane), and vice-versa. Each mode has a dif-ferent outer controller, while the low-level loops are the same. Simulation results with a realistic system model in-dicate that the controller can achieve good performance and robustness in all flight conditions, notwithstanding its simplicity and ease of implementation, and carry out the wanted pumping cycles. This work builds on a re-cently presented contribution [2], where an untethered system was considered.

Example of prototypes of the considered hybrid drones during tests in the Swiss Alps

References:

[1] Skypull SA. [Online]. Available: https://www.skypull.technology (last accessed September 2019)

[2] D. Todeschini, L. Fagiano, C. Micheli and A. Cattano. Control of vertical take off, dynamic flight and landing of hybrid drones for air-borne wind energy systems. In Proc. of the 2019 American Control Conference (ACC), Philadelphia, PA, USA, pp. 2177-2182 (2019)