Pole-zero cancellations and closed-loop properties of an H mixed sensitivity design problem

M. C. Tsai, E. J.M. Geddes, I. Postlethwaite

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)


We examine an H mixed sensitivity design problem in order to gain an understanding of the pole-zero cancellation phenomenon that is known to occur with such designs. It is shown how the pole-zero cancellation phenomenon is dependent upon the choice of weighting functions used in the problem formulation, and a particular construction of weighting function is given that gives the designer freedom to exploit or prevent the phenomenon. Furthermore, this weighting function is then a mechanism for (partial) pole placement. As a consequence of the construction of this weighting function, it is shown that for a certain class of plant, the Normalized Coprime Factor design procedure of Glover and McFarlane (1989, Robust Controller Design Using Normalized Coprime Factor Plant Descriptions. Springer-Verlag, Berlin) gives rise to (possibly undesirable) pole-zero cancellations. The results are presented for multivariable systems, and are illustrated with a simple design example.

Original languageEnglish
Pages (from-to)519-530
Number of pages12
Issue number3
Publication statusPublished - 1992 May

All Science Journal Classification (ASJC) codes

  • Control and Systems Engineering
  • Electrical and Electronic Engineering


Dive into the research topics of 'Pole-zero cancellations and closed-loop properties of an H mixed sensitivity design problem'. Together they form a unique fingerprint.

Cite this