Controller synthesis for multivariable nonlinear nonminimum-phase processes

A general nonlinear controller design method for multivariable nonminimum-phase systems is presented that utilizes a class of synthetic outputs which are statically equivalent to the process outputs. A systematic procedure for the selection of particular synthetic outputs, which lead to prescribed transmission zeros, is outlined. The selected synthetic outputs are then used to construct a model-state feedback controller, which is guaranteed to induce zero steady-state error to the original plant outputs. The proposed control scheme is illustrated in a simulation case study for a multivariable nonisothermal CSTR, where a series/parallel van de Vusse reaction is taking place