A Robust Nonlinear Tracking MPC using qLPV Embedding and Zonotopic
Uncertainty Propagation
Abstract
In this paper, we propose a novel Nonlinear Model Predictive Control
(NMPC) framework for tracking for piece-wise constant reference signals.
The main novelty is the use quasi-Linear Parameter Varying (qLPV)
embeddings in order to describe the nonlinear dynamics. Furthermore,
these embeddings are exploited by an extrapo- lation mechanism, which
provides the future behaviour of the scheduling parameters with bounded
estimation error. Therefore, the resulting NMPC becomes compu-
tationally efficient (comparable to a Quadratic Programming algorithm),
since, at each sampling period, the predictions are linear. Benefiting
from artificial target variables, the method is also able to avoid
feasibility losses due to large set-point variations. Robust constraint
satisfaction, closed-loop stability, and recursive fea- sibility
certificates are provided, thanks to uncertainty propagation zonotopes
and parameter-dependent terminal ingredients. A benchmark example is
used to illustrate the effectiveness of the method, which is compared to
state-of-the-art techniques.