Frequency-domain-based, control-relevant model reduction for nonlinear plants

C. Shreesha, Ravindra D. Gudi, P. S.V. Nataraj

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Chemical plants exhibit nonlinear dynamics that need to be captured accurately for modelbased control. This paper focuses on a frequency-domain-based, control-relevant model reduction strategy for nonlinear process plants. The generalized frequency response function proposed for the nonlinear plants has been used to analyze the characteristics of nonlinear structures in the frequency domain, from a control-relevant viewpoint. Control-relevant model reduction is sought by minimizing the mismatch between a higher order, nonlinear proxy plant and candidate reduced order nonlinear model structures. The minimization is proposed to be done by prefiltering of identification data to shape the mismatch in a control-relevant manner. For these prefilters as well, candidate linear and nonlinear structures are evaluated and an algorithm to design the prefilters to reflect the servo and regulatory performance specifications is proposed. The model reduction methodology is used along with a nonlinear internal model control (NIMC) algorithm and is demonstrated on a simple simulation as well as on a representative nonlinear chemical reactor studied in the literature.

Original languageEnglish
Pages (from-to)5006-5015
Number of pages10
JournalIndustrial and Engineering Chemistry Research
Issue number20
Publication statusPublished - 02-10-2002

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • General Chemical Engineering
  • Industrial and Manufacturing Engineering


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