Sparse RKHS estimation via globally convex optimization and its application in LPV-IO identification

Autor: Dario Piga, Mohamed Abdelmonim Hassan Darwish, Roland Tóth, Vincent Laurain
Přispěvatelé: Control Systems, EAISI High Tech Systems, Centre de Recherche en Automatique de Nancy (CRAN), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Eindhoven University of Technology [Eindhoven] (TU/e), DALLE MOLLE INSTITUTE FOR ARTIFICIAL INTELLIGENCE IDSIA LUGANO CHE, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Assiut University
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Zdroj: Automatica, 115:108914. Elsevier
Automatica
Automatica, Elsevier, 2020, 115, pp.108914. ⟨10.1016/j.automatica.2020.108914⟩
ISSN: 0005-1098
Popis: International audience; Function estimation using the Reproducing Kernel Hilbert Space (RKHS) framework is a powerful tool for identification of a general class of nonlinear dynamical systems without requiring much a priori information on model orders and nonlinearities involved. However, the high degrees-of-freedom (DOFs) of RKHS estimators has its price, as in case of large scale function estimation problems, they often require a serious amount of data samples to explore the search space adequately for providing high-performance model estimates. In cases where nonlinear dynamic relations can be expressed as a sum of functions, the literature proposes solutions to this issue by enforcing sparsity for adequate restriction of the DOFs of the estimator, resulting in parsimonious model estimates. Unfortunately, all existing solutions are based on greedy approaches, leading to optimization schemes which cannot guarantee convergence to the global optimum. In this paper, we propose an $\ell_1$-regularized non-parametric RKHS estimator which is the solution of a quadratic optimization problem. Effectiveness of the scheme is demonstrated on the non-parametric identification problem of LPV-IO models where the method solves simultaneously (i) the model order selection problem (in terms of number of input–output lags and input delay in the model structure) and (ii) determining the unknown functional dependency of the model coefficients on the scheduling variable directly from data. The paper also provides an extensive simulation study to illustrate effectiveness of the proposed scheme.
Databáze: OpenAIRE