Frequency-domain subspace identification of linear time-periodic (LTP) systems

Uyanık, İsmail
Saranlı, Uluç
Ankaralı, Mustafa Mert
Cowan, Noah J.
Morgül, Ömer
This paper proposes a new methodology for subspace-based state-space identification for linear time-periodic (LTP) systems. Since LTP systems can be lifted to equivalent linear time-invariant (LTI) systems, we first lift input-output data from an unknown LTP system as if they were collected from an equivalent LTI system. Then, we use frequency-domain subspace identification methods to find the LTI system estimate. Subsequently. we propose a novel method to obtain a time-periodic realization for the estimated lifted LTI system by exploiting the specific parametric structure of Fourier series coefficients of the frequency-domain lifting method. Our method can be used to obtain state-space estimates for unknown LTP systems as well as to obtain Floquet transforms for known LTP systems.
IEEE Transactions on Automatic Control


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Citation Formats
İ. Uyanık, U. Saranlı, M. M. Ankaralı, N. J. Cowan, and Ö. Morgül, “Frequency-domain subspace identification of linear time-periodic (LTP) systems,” IEEE Transactions on Automatic Control, pp. 2529–2536, 2019, Accessed: 00, 2020. [Online]. Available: