Abstract :
In two previous publications, the authors have shown that normal form theory, a method used extensively
in dynamic analysis, can be applied in the structure identification of nonlinear systems. In particular, normal
form theory bridges the gap between structure of a nonlinear, low order polynomial dynamical system and
the behavior it is able to predict or represent. This is important because knowing a systemʹs dynamic
behavior automatically leads to a simple nonlinear normal form model that can be used for (nonlinear) control.
Previously, only two-dimensional normal form models were derived. For this paper, simple, n-dimensional,
low order polynomial dynamical models will be derived that can represent a nonlinear system with
multiple steady states or a limit cycle in the operating region of interest. Using as a plant the nonisothermal
Continuous Stirred Tank Reactor with consecutive reactions (A~B~C), it is shown that identification
and control of this three-dimensional system using the aforementioned normal form models is
feasible.
