Model-based control of unstable, non-minimum-phase, nonlinear processes

A model-based control system is presented for nonlinear unconstrained processes. It is applicable to stable and unstable processes, whether non-minimum- or minimum-phase. The control system includes a nonlinear state feedback and a reduced-order nonlinear state observer. The state feedback induces an approximately linear response to state variables of the process. The state feedback is derived by solving a continuous-time moving-horizon optimization problem. The application and performance of the control system are shown by implementing it on a chemical reactor with multiple steady states. The control system is used to operate the reactor at one of the steady states, which is unstable and non-minimum-phase. The simulation results show that the closed-loop system is globally asymptotically stable.