Heading Angle Control for Path–following Guidance with Large Domain of Attraction of a Pumping Kite Generator

Manuel C.R.M. Fernandes PhD Researcher Universidade do Porto Faculdade de Engenharia Dept. of Electrical & Computer Engineering

Systec/ISR, Upwind Project Rua Dr. Roberto Frias, s/n

4200-465 Porto Portugal mcrmf@fe.up.pt www.upwind.pt

Heading Angle Control for Path–following Guidance with

Large Domain of Attraction of a Pumping Kite Generator

Manuel C.R.M. Fernandes, Luís Tiago Paiva, Fernado A.C.C. Fontes SYSTECśISR, Universidade do Porto

We address the problem of controlling the heading angle of a power kite to follow a prescribed geometric path. In a first stage, we solve an optimal control problem to de-termine a kite trajectory that maximizes the energy gen-erated during the traction phase of a Pumping Kite Gen-erator. (This problem has been widely studied in the liter-ature; see e.g. [1] and references therein.) The obtained trajectory is then used to define a timeśindependent ge-ometrical path, parameterized in the azimuth and eleva-tion angle, in spherical coordinates, as well as a target speed under which the path should be followed. In a second stage, such path is used as the reference in a pathśfollowing guidance method, based on a modified nonlinear guidance logic, given by an explicit expression. Such controller has been shown to be asymptotically sta-ble and has demonstrated a superior performance in fol-lowing straight and curved paths when compared with other common navigational guidance laws. In the mod-ified controller, the domain of attraction is significantly enlarged, which represents our main contribution (see [2]). Robustness of the method under fast changing wind conditions, such as wind gusts, is analyzed in simulation.

Reference path (dashed-blue line) closely followed by the kite tra-jectory (solid red) during production phase.

References:

[1] Paiva, L.T., Fontes, F.A.C.C.: Optimal Control Algorithms with Adaptive TimeśMesh Refinement for Kite Power Systems. Energies 11(3):475, February (2018)

[2] Silva, G.B., Paiva, L.T., Fontes, F.A.C.C.: A Pathśfollowing Guid-ance Method for Airborne Wind Energy Systems with Large Domain of Attraction. IFAC Proceedings of 2019 American Control Confer-ence, pp. 2771ś2776, Philadelphia, USA, July (2019)