On positive realness and negative imaginariness of uncertain discrete-time state-space symmetric systems

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Original languageEnglish
Pages (from-to)1406-1417
Journal / PublicationInternational Journal of Systems Science
Issue number8
Online published18 May 2020
Publication statusPublished - Jun 2020
Externally publishedYes


This paper provides an analysis of uncertain discrete-time negative imaginary and positive real systems with state-space symmetry. First, a necessary and sufficient condition is provided for a minimal state-space symmetric system to be discrete-time positive real or discrete-time negative imaginary. Then, based on the discrete-time symmetric negative imaginary and positive real lemmas, bounds on symmetrically structured perturbations that maintain the negative imaginariness and positive realness of a discrete-time state-space symmetric system are derived. Finally, an RL network example is provided to illustrate the main results of the paper.

Research Area(s)

  • Discrete time, negative imaginary systems, positive real systems, state-space symmetric systems, uncertain systems, H-INFINITY CONTROL, STABILITY ANALYSIS, MODEL-REDUCTION, STABILIZATION, ROBUSTNESS, BOUNDS