Robust design method for discrete-time controllers with simple structures

Min Lang Lin, Shyh Hong Hwang

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


This paper first presents the design of a discrete-time general-structure controller, the order of which is determined by the process model order. Through the modified internal model control and dominant pole placement algorithms, the direct design is achievable by specifying one to three readily understandable parameters. Simple-structure controllers with user-specified orders can then be derived based on ingenious approximations of the general controller design. For example, a low-order proportional-integral-derivative and a high-order controller are obtainable in the same fashion. Furthermore, with a newly developed index for stability robustness, a methodology is proposed to optimize the controller designs of various structures. It is concluded that the resultant simple-structure controllers are vastly superior to the general-structure controller in almost all respects. The method is demonstrated with a wide range of process dynamics including time delay, right-half-plane and left-half-plane zeros, low- to high-order lags, integrators, and unstable poles.

Original languageEnglish
Pages (from-to)2705-2715
Number of pages11
JournalIndustrial and Engineering Chemistry Research
Issue number11
Publication statusPublished - 2002 May 29

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Chemical Engineering(all)
  • Industrial and Manufacturing Engineering


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