OUTPUT-FEEDBACK CONTROL OF NONMINUMUM-PHASE NONLINEAR PROCESSES

This work concerns the development of a general framework for the anal ysis and output feedback control of open-loop stable nonminimum-phase nonlinear processes. A Smith-type abstract operator structure is intro duced, allowing the reduction of the controller synthesis problem for nonminimum-phase processes to the one for minimum-phase processes. Sta te-space methods are used to derive a reduced-order output feedback co ntroller that induces a desired input/output behavior for processes wi th unstable inverse dynamics and deadtime. The underlying structure of the reduced-order controller is also identified and studied. Finally, an example from a class of chemical reaction systems with nonminimum- phase characteristics is used for evaluating the performance and robus tness of the developed control method.