AIChE Journal, Vol.42, No.1, 187-203, 1996
Discrete-Time Nonlinear Feedback-Control of Multivariable Processes
Discrete-time nonlinear feedback control laws are derived for multivariable nonlinear processes, whose "delay-free" parts are minimum phase. These include mixed error- and state-feedback, error-feedback, and mixed error- and output-feedback laws, which can induce lineal input-output closed-loop response. This study is carried out within the framework of the discrete-time globally linearizing control. The broader class of nonlinear processes, in which controlled outputs as well as some other process variables are measured, are also considered. A mired error- and output-feedback control law is derived for this class of processes. The conditions under which the mixed error- and output-feedback can be applied to a process operating at or around an open-loop unstable equilibrium point are determined. The application and performance of the derived control laws are illustrated by the numerical simulation of a chemical reactor.