© 2001

Digital Controller Implementation and Fragility

A Modern Perspective

  • Robert S. H. Istepanian
  • James F. Whidborne


  • Presents the latest advances in the design methodologies and implementation issues of digital controller structures

  • Assembles a number of contributions from distinctive researchers working in these areas to present a state-of-the-art view of the issues concerning the implementation of modern advanced controllers


Part of the Advances in Industrial Control book series (AIC)

Table of contents

  1. Front Matter
    Pages i-xix
  2. Lee H. Keel, Shankar P. Bhattacharyya
    Pages 13-24
  3. Ian J. Fialho, Tryphon T. Georgiou
    Pages 105-121
  4. Pertti M. Mäkilä, Juha Paattilammi
    Pages 161-181
  5. Wassim M. Haddad, Joseph R. Corrado
    Pages 183-211
  6. Guang-Hong Yang, Jian Liang Wang, Yeng Chai Soh
    Pages 213-228
  7. Mauricio C. de Oliveira, Robert E. Skelton
    Pages 229-251
  8. Inés del Campo, José M. Tarela, Koldo Basterretxea
    Pages 253-274
  9. Back Matter
    Pages 275-277

About this book


In the usual process of control system design, the assumption is made that the controller is implemented exactly. This assumption is usually reasonable, since clearly, the plant uncertainty is the most significant source of uncertainty in the control system, while controllers are implemented with high-precision hardware. However, inevitably, there will be some amount of uncertainty in the controller, a fact that is largely ignored in existing modern advanced robust control techniques. If the controller is implemented by analogue means, there are some tolerances in the analogue components. More commonly, the controller will be implemented digitally, and consequently there will be uncertainty involved with the quantization in the analogue-digital conversion and rounding in the parameter representation and in the numerical computations. A failure to account for these uncertainties in the controller may result in a controller that is "fragile". A controller is fragile in the sense that very small perturbations in the coefficients of the designed controller destabilize the closed-loop control system.
This book collects a number of articles which consider the problems of finite-precision computing in digital controllers and filters. Written by leading researchers, topics that the book covers include:
- analysis of fragility and finite-precision effects;
- design of optimal controller realizations;
- design of non-fragile robust controllers;
- design of low-complexity digital controllers;
- analysis of quantization effects in fuzzy controllers.


Hardware algorithms complexity control control system development fuzzy control fuzzy controller identification optimal control optimization programming robust control simulation stability

Editors and affiliations

  • Robert S. H. Istepanian
    • 1
  • James F. Whidborne
    • 2
  1. 1.Department of Electronic and Computer EngineeringBrunel UniversityUxbridge, MiddlesexUK
  2. 2.Department of Mechanical EngineeringKing’s College LondonLondonUK

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