Manuel Soler Assistant Professor Universidad Carlos III de Madrid
Bioengineering and Aerospace Engineering Department Dynamics and Control in Aerospace
Systems Group Avda. Universidad 30 28911 Leganés (Madrid) Spain masolera@ing.uc3m.es www.aero.uc3m.es
Determination of Optimal Control Laws in Airborne Wind Energy Scenarios With a
Self-Consistent Kite Dynamics Model
Daniel Expósito, Manuel Soler, Gonzalo Sánchez-Arriaga Universidad Carlos III de Madrid
In the reel-in and real out phases of yo-yo airborne wind energy generation schemes, appropriate control laws should be imposed to the lengths of the bridle and the main tether of a power kite. The determination of the op-timal control laws that maximize the energy production for a given wind conditions is a complex problem that re-quires a kite flight simulator and robust and efficient op-timization algorithms. This work makes use of a recently proposed kite flight simulator based on Lagrangian for-mulation that explicitly removes the tension force from the equations of motion. Although being a low-order dy-namical system with only five degrees of freedom, the simulator captures self-consistently the dynamics of the full system (kite, bridle and tether) and provides a reli-able framework with a moderate computation cost. Op-timal control laws for the lengths of the three lines of the bridle and the tether are determined by embedding the kite flight simulator in a homemade optimal control li-brary. The continuous-time optimal control problem is transcribed into a nonlinear programming problem us-ing a collocation method and imposus-ing periodic bound-ary conditions for the trajectories. The optimal open-loop control laws that maximize the generated power were de-termined by using an interior point solver. As expected, optimal trajectories involve a reel-out phase with the kite flying in cross-wind conditions and a reel-in phase at low angle of attack. The stability of the resulting periodic
orbits is studied by using Floquet theory, and the main features of the trajectories are compared with previous works already available in the literature.
Figure: Methodological block diagram for the determination of op-timal control laws in a self-consistent kite dynamics model.
References:
[1] J. Alonso-Pardo and G. Sánchez-Arriaga: Kite Model with Bridle Control for Wind-Power Generation. Journal of Aircraft 52(3), 917-923 (2015)
