A Control Solution for a Tethered Kite Trajectory Tracking with Application to Ship Propulsion

In the field of clean and green energy production systems, airborne wind energy (AWE) systems are really promising technologies. Replacing lightweight tethers with expensive towers, is an innovative solution to get energy from higher altitudes than classical wind turbines. But AWE systems can also be used to produce a traction force through a fast-flying airfoil, or kite. In this paper, the traction force is supposed to be used for ship propulsion. Such an application is permitted if the kite is kept on an appropriate trajectory. This paper thus considers the design of an automatic pilot for trajectory tracking. Its design requires a path-planning and a control strategies that are described here. In terms of control strategy, a robust CRONE controller is designed based on a family of linear models that stands for the nonlinear model of the kite and obtained numerically around several trajectories and for various flight conditions. Efficient trajectories for ship traction being periodic, a method involving tools dedicated to time-varying periodic systems is then used to validate the approach used for CRONE controller design.