Optimal model reduction of discrete-time systems

A. S. Hauksdóttir*

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review

4 Citations (Scopus)


Closed-form expressions of transfer function responses are used in this paper towards model-reduction of n-th order discrete-time systems. The contribution of each eigenvalue to the output for a unit step input is evaluated, thus defining the dominant eigenvalues. The reduced-order model is set up retaining the most contributing eigenvalues, maintaining the same DC gain as the original system, but leaving other numerator coefficients to be determined. Then a cost function is formed measuring the discrete pulse response deviation between the original and the reduced-order model. The cost function is subsequently minimized, rendering new numerator coefficients for the reduced model. The resulting reduced-order model is easily computed, maintains stability for an originally stable system, and renders time responses practically identical to the original system's.

Original languageEnglish
Pages (from-to)2584-2589
Number of pages6
JournalProceedings of the American Control Conference
Publication statusPublished - 2001
Event2001 American Control Conference - Arlington, VA, United States
Duration: 25 Jun 200127 Jun 2001

Other keywords

  • Model reduction
  • N-th order linear discrete-time systems
  • Optimal zeros


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