Subsystem identification of multivariable feedback and feedforward systems

Xingye Zhang, Jesse B. Hoagg

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


We present a frequency-domain technique for identifying multivariable feedback and feedforward subsystems that are interconnected with a known subsystem. This subsystem identification algorithm uses closed-loop input–output data, but no other system signals are assumed to be measured. In particular, neither the feedback signal nor the outputs of the unknown subsystems are assumed to be measured. We use a candidate-pool approach to identify the feedback and feedforward transfer function matrices, while guaranteeing asymptotic stability of the identified closed-loop transfer function matrix. The main analytic result shows that if the data noise is sufficiently small and the candidate pool is sufficiently dense, then the parameters of the identified feedback and feedforward transfer function matrices are arbitrarily close to the true parameters.

Original languageEnglish
Pages (from-to)131-137
Number of pages7
StatePublished - Oct 1 2016

Bibliographical note

Funding Information:
This work was supported by the National Science Foundation through CMMI–1405257 . The material in this paper was not presented at any conference. This paper was recommended for publication in revised form by Associate Editor Er-Wei Bai under the direction of Editor Torsten Söderström.

Publisher Copyright:
© 2016 Elsevier Ltd


  • Closed-loop system identification
  • Feedback and feedforward subsystems
  • Frequency-domain system identification
  • Stability
  • Subsystem identification

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Electrical and Electronic Engineering


Dive into the research topics of 'Subsystem identification of multivariable feedback and feedforward systems'. Together they form a unique fingerprint.

Cite this