Orbit control for a power generating airfoil based on nonlinear MPC

The Airborne Wind Energy paradigm proposes to generate energy by flying a tethered airfoil across the wind flow. An essential problem posed by Airborne Wind Energy is the control of the tethered airfoil trajectory during power generation. Tethered flight is a fast, strongly nonlinear, unstable and constrained process, motivating control approaches based on fast Nonlinear Model Predictive Control. In this paper, a computationally efficient 6-DOF control model for a high performance, large-scale, rigid airfoil is proposed. A control scheme based on receding-horizon Nonlinear Model Predictive Control to track reference trajectories is applied to the proposed model. In order to make a real-time application of Nonlinear Model Predictive Control possible, a Real-Time Iteration scheme is proposed and its performance investigated.

[1]  Lucy Y. Pao,et al.  Control of wind turbines: Past, present, and future , 2009, 2009 American Control Conference.

[2]  Moritz Diehl,et al.  A Lyapunov Function for Economic Optimizing Model Predictive Control , 2011, IEEE Transactions on Automatic Control.

[3]  H. Bock,et al.  A Multiple Shooting Algorithm for Direct Solution of Optimal Control Problems , 1984 .

[4]  MORITZ DIEHL,et al.  A Real-Time Iteration Scheme for Nonlinear Optimization in Optimal Feedback Control , 2005, SIAM J. Control. Optim..

[5]  Jan Van Impe,et al.  Towards enhanced weight selection for (N)MPC via multi-objective optimisation , 2012 .

[6]  Moritz Diehl,et al.  Real-Time Control of a Kite-Model Using an Auto-Generated Nonlinear MPC Algorithm , 2011 .

[7]  Moritz Diehl,et al.  ACADO toolkit—An open‐source framework for automatic control and dynamic optimization , 2011 .

[8]  M. Diehl,et al.  Real-time optimization and nonlinear model predictive control of processes governed by differential-algebraic equations , 2000 .

[9]  Ervin Bossanyi,et al.  Wind Energy Handbook , 2001 .

[10]  Moritz Diehl,et al.  Optimal control for power generating kites , 2007, 2007 European Control Conference (ECC).

[11]  M. L. Loyd,et al.  Crosswind kite power (for large-scale wind power production) , 1980 .

[12]  Ervin Bossanyi,et al.  Further load reductions with individual pitch control , 2005 .

[13]  Moritz Diehl,et al.  Windenergienutzung mit schnell fliegenden Flugdrachen: eine Herausforderung für die Optimierung und RegelungWind Power via Fast Flying Kites: a Challenge for Optimization and Control , 2009, Autom..

[14]  M. V. Cook.  Flight Dynamics Principles , 1997 .

[15]  Moritz Diehl,et al.  An auto-generated real-time iteration algorithm for nonlinear MPC in the microsecond range , 2011, Autom..