Finite Sample Analysis for a Class of Subspace Identification Methods

Fuente: arXiv
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Autori principali: He, Jiabao, Ziemann, Ingvar, Rojas, Cristian R., Hjalmarsson, Håkan
Natura: Preprint
Pubblicazione: 2024
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author He, Jiabao
Ziemann, Ingvar
Rojas, Cristian R.
Hjalmarsson, Håkan
author_facet He, Jiabao
Ziemann, Ingvar
Rojas, Cristian R.
Hjalmarsson, Håkan
contents While subspace identification methods (SIMs) are appealing due to their simple parameterization for MIMO systems and robust numerical realizations, a comprehensive statistical analysis of SIMs remains an open problem, especially in the non-asymptotic regime. In this work, we provide a finite sample analysis for a class of SIMs, which reveals that the convergence rates for estimating Markov parameters and system matrices are $\mathcal{O}(1/\sqrt{N})$, in line with classical asymptotic results. Based on the observation that the model format in classical SIMs becomes non-causal because of a projection step, we choose a parsimonious SIM that bypasses the projection step and strictly enforces a causal model to facilitate the analysis, where a bank of ARX models are estimated in parallel. Leveraging recent results from finite sample analysis of an individual ARX model, we obtain an overall error bound of an array of ARX models and proceed to derive error bounds for system matrices via robustness results for the singular value decomposition.
format Preprint
id arxiv_https___arxiv_org_abs_2404_17331
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Finite Sample Analysis for a Class of Subspace Identification Methods
He, Jiabao
Ziemann, Ingvar
Rojas, Cristian R.
Hjalmarsson, Håkan
Systems and Control
While subspace identification methods (SIMs) are appealing due to their simple parameterization for MIMO systems and robust numerical realizations, a comprehensive statistical analysis of SIMs remains an open problem, especially in the non-asymptotic regime. In this work, we provide a finite sample analysis for a class of SIMs, which reveals that the convergence rates for estimating Markov parameters and system matrices are $\mathcal{O}(1/\sqrt{N})$, in line with classical asymptotic results. Based on the observation that the model format in classical SIMs becomes non-causal because of a projection step, we choose a parsimonious SIM that bypasses the projection step and strictly enforces a causal model to facilitate the analysis, where a bank of ARX models are estimated in parallel. Leveraging recent results from finite sample analysis of an individual ARX model, we obtain an overall error bound of an array of ARX models and proceed to derive error bounds for system matrices via robustness results for the singular value decomposition.
title Finite Sample Analysis for a Class of Subspace Identification Methods
topic Systems and Control
url https://arxiv.org/abs/2404.17331