NONLINEAR CONTROL OF NONLINEAR NONMINIMUM PHASE SYSTEMS WITH INPUT MULTIPLICITIES

A model reference nonlinear controller with PI action is applied to a CSTR, with Van de Vusse reaction, which shows a nonlinear nonminimum phase behaviour with input multiplicities in the product concentration. The controller is designed separately for controlling the product concentration via the control of reactant concentration of the exit stream. In both cases, a perfect control action is obtained but with a different levels of manipulated variable, one with a larger value and the later case with a lower value input. Theoretical analysis on the robustness of the controller is also provided. Simulation results show the successful performance of the proposed nonlinear controller.