Trajectory planning and tracking via MPC for transient control of liquid-propellant rocket engines
Résumé
The new scenarios associated with launchers reusability force the enhancement of control algorithms for their liquid-propellant rocket engines. The transient phases of these engines are generally executed in open loop. The goal of this paper is to improve the control performance and robustness throughout the fully continuous phase of the start-up transient of a generic gas-generator cycle. The controller has to guarantee an accurate tracking in terms of combustion-chamber pressure and chambers mixture ratios, as well as to satisfy a set of hard operational constraints. The selected strategy comprises a nonlinear preprocessor and a linearised MPC (Model-Predictive Control) controller, making use of nonlinear state-space models of the engine. The former plans the reference trajectory of states and control, which is tracked by the latter. Control goals are attained with sufficient accuracy while verifying constraints within the desired throttling range. Robustness to internal parameters variations is considered in the MPC controller by means of an epigraph formulation of the minimax robust optimisation problem, where a finite set of parameter-variation scenarios is treated.
Origine : Fichiers produits par l'(les) auteur(s)
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