文档介绍：Linear Control of Nonlinear Processes:
Recent Developments and Future Directions
Michael Nikolaou and Pratik Misra
Chemical Engineering Dept.
University of Houston
Houston, TX 77204-4004
******@
CEPAC 2001, Guarujá, Sao Paulo, Brazil,
Abstract
Virtually all chemical processes are nonlinear, but for several of them linear feedback
control is adequate. Therefore, before nonlinear controller design is attempted, it is
natural to ask “When is linear control adequate for a nonlinear process?” to ensure
favorable cost/benefit ratio. Consequently, methods are needed that quantify the
nonlinearity of a process within the context of assessing whether linear control is
adequate or nonlinear control is warranted. In this work we summarize efforts towards
this end and elaborate on our latest research in this area. Specifically, we present a
rigorous and general theoretical framework as well as an associated, heuristically
putational methodology that allow not only analysis but also synthesis of a
linear control system for a nonlinear process. Application to the multivariable case is
presented. Potential future developments within this framework are discussed.
1 Introduction
A basic question: Linear or nonlinear control?
Interest in nonlinear feedback control of chemical processes has been steadily increasing over the
last several years. This is due both to the pronounced nonlinear nature of several chemical
processes (whether in mature or emerging fields) and to the increased sensing putational
capabilities afforded by modern sensors, computers, algorithms, and software. Such capabilities
have been claimed and at times proven to offer benefits in better operation and control of
chemical processes. However, nonlinear control systems usually pose substantially higher data,
design, implementation, and maintenance demands than linear control syst