Modeling of nonlinear systems for linear robust control theory: Identification via linear model sets under shifts of operating points

Considering shifts of operating points of nonlinear systems, total methods of identifying linearized models and designing feedback control systems for the nonlinear systems are presented. In the methods, a set of linear models is identified, which includes the linearized models of the nonlinear system at all the points in the entire range of expected changes of the operating point. For the model set, a linear stabilizing controller is designed by linear robust control theory and it is applied to the original nonlinear system. The obtained feedback control system for the nonlinear system is valid since all the expected equilibrium states are asymptotically stable.