DISCRETE-TIME NONLINEAR FEEDBACK-CONTROL OF MULTIVARIABLE PROCESSES

Discrete-time nonlinear feedback control laws are derived for multivar iable nonlinear processes, whose ''delay-free'' parts are minimum phas e. These include mixed error- and state-feedback, error-feedback, and mixed error- and output-feedback laws, which can induce lineal input-o utput closed-loop response. This study is carried out within the frame work of the discrete-time globally linearizing control. The broader cl ass of nonlinear processes, in which controlled outputs as well as som e other process variables are measured, are also considered. A mired e rror- and output-feedback control law is derived for this class of pro cesses. The conditions under which the mixed error- and output-feedbac k can be applied to a process operating at or around an open-loop unst able equilibrium point are determined. The application and performance of the derived control laws are illustrated by the numerical simulati on of a chemical reactor.