ABSTRACT
Linear control strategies provide powerful control design tools under general hypotheses as seen in the previous chapters. The limitation of the linear control design is that a nominal model, expressed around a single operating point, may not be able to represent the nonlinear plant in the whole operating range. Therefore, the effectiveness of linear controllers may be compromised when the operation strays away from the nominal operating point. In this chapter, the concept of gain-scheduling is introduced first as a natural extension of the linear approaches studied so far. This is followed by the operating regime modeling approach as the basis for developing multiple (linear) models towards the representation of the nonlinear process dynamics and for implementing multilinear model-based control, a rigorous generalization of the gain-scheduling approach. Finally, an introduction to the exact linearizing control strategy is provided where the nonlinear model is explicitly introduced into the problem.
