Data-Driven Estimation of Vinnicombe metric

Fuente: arXiv
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Main Authors: Guerrero, Margarita A., Sandberg, Henrik, Rojas, Cristian R.
Format: Preprint
Published: 2026
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author Guerrero, Margarita A.
Sandberg, Henrik
Rojas, Cristian R.
author_facet Guerrero, Margarita A.
Sandberg, Henrik
Rojas, Cristian R.
contents Quantifying model mismatch in a control-relevant manner is fundamental in robust control. A well-known metric for this purpose is the $ν$-gap, or Vinnicombe metric, which measures the discrepancy between a nominal model and the real system from a closed-loop viewpoint. However, its computation typically requires explicit knowledge of the true system. In this letter, we propose an identification-free, data-driven method to estimate the $ν$-gap between discrete-time SISO systems directly from input-output experiments. The method is complemented by a data-driven winding-number test, based on Welch-type averaging, to verify a required topological condition for the computation of the metric. Numerical simulations on heavy-duty gas-turbine models and a textbook example show that the proposed estimate closely matches MATLAB$^©$ \texttt{gapmetric}, while correctly detecting cases in which the admissibility conditions fail.
format Preprint
id arxiv_https___arxiv_org_abs_2603_17545
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Data-Driven Estimation of Vinnicombe metric
Guerrero, Margarita A.
Sandberg, Henrik
Rojas, Cristian R.
Optimization and Control
Quantifying model mismatch in a control-relevant manner is fundamental in robust control. A well-known metric for this purpose is the $ν$-gap, or Vinnicombe metric, which measures the discrepancy between a nominal model and the real system from a closed-loop viewpoint. However, its computation typically requires explicit knowledge of the true system. In this letter, we propose an identification-free, data-driven method to estimate the $ν$-gap between discrete-time SISO systems directly from input-output experiments. The method is complemented by a data-driven winding-number test, based on Welch-type averaging, to verify a required topological condition for the computation of the metric. Numerical simulations on heavy-duty gas-turbine models and a textbook example show that the proposed estimate closely matches MATLAB$^©$ \texttt{gapmetric}, while correctly detecting cases in which the admissibility conditions fail.
title Data-Driven Estimation of Vinnicombe metric
topic Optimization and Control
url https://arxiv.org/abs/2603.17545