49 Milan Vukov KU Leuven Kasteelpark Arenberg 10 3001 Leuven Belgium milan.vukov@esat.kuleuven.be www.kuleuven.be
Fast Solvers for Nonlinear Optimal Control and Estimation
with Applications to Tethered Kites
Milan Vukov, Rien Quirynen, Moritz Diehl KU Leuven
Tethered flight can be characterized as a strongly non- linear and unstable process. Those facts motivate usage of control and estimation techniques based on nonlinear optimization. Moreover, the process dynamics requires fast sampling times, thus algorithms which can be executed in millisecond range.
Fast nonlinear model predictive control (NMPC) and mov-ing horizon estimators (MHE) solvers are developed for mechatronic and aerospace applications. Here we present an automatic C-code generation strategy for real-time NMPC and MHE. The automatic code generation is realized as the ACADO Code Generation tool within the software pack-age for dynamic optimization ACADO Toolkit.
The tool enables one to export highly customized solvers for NMPC and MHE which allow for very advanced control strat-egies including nonlinear measurement functions as well as the formulation of general nonlinear constraints along the process trajectory. In the context of estimation, the tool pro-vides an elegant procedure for multi-rate sensor fusion. This procedure for sensor fusion removes the need for intermedi-ate steps, e.g. averaging high frequency measurements be-fore feeding them to the estimator.
Simulation results provide insight into some benchmarks, showing very promising performance and execution times. Furthermore, we present real flight experimental results per-formed on the kite carousel at KU Leuven, Belgium.
