Recursive identification of structured systems

An instrumental-variable approach applied to mechanical systems

Journal Article (2025)
Author(s)

Koen Classens (Eindhoven University of Technology)

Rodrigo A. González (Eindhoven University of Technology)

Tom Oomen (TU Delft - Team Jan-Willem van Wingerden, Eindhoven University of Technology)

Research Group
Team Jan-Willem van Wingerden
DOI related publication
https://doi.org/10.1016/j.ejcon.2025.101238
More Info
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Publication Year
2025
Language
English
Research Group
Team Jan-Willem van Wingerden
Volume number
84
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Abstract

Online system identification algorithms are widely used for monitoring, diagnostics and control by continuously adapting to time-varying dynamics. Typically, these algorithms consider a model structure that lacks parsimony and offers limited physical interpretability. The objective of this paper is to develop a real-time parameter estimation algorithm aimed at identifying time-varying dynamics within an interpretable model structure. An additive model structure is adopted for this purpose, which offers enhanced parsimony and is shown to be particularly suitable for mechanical systems. The proposed approach integrates the recursive simplified refined instrumental variable method with block-coordinate descent to minimize an exponentially-weighted output error cost function. This novel recursive identification method delivers parametric continuous-time additive models and is applicable in both open-loop and closed-loop controlled systems. Its efficacy is shown using numerical simulations and is further validated using experimental data to detect the time-varying resonance dynamics of a flexible beam system. These results demonstrate the effectiveness of the proposed approach for online and interpretable estimation for advanced monitoring and control applications.