This work concerns the development of a general framework for the analysis and output feedback control of open-loop stable nonminimum-phase nonlinear processes. A Smith-type abstract operator structure is introduced, allowing the reduction of the controller synthesis problem for nonminimum-phase processes to the one for minimum-phase processes. State-space methods are used to derive a reduced-order output feedback controller that induces a desired input/output behavior for processes with 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 robustness of the developed control method.
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AcknowZedyemrnt~Financial support from the National Science Foundation, Grant No. CT%8912836 is gratefully acknowledged. The authors also wish to thank Masoud Soroush for his suggestions on the simulation example.