Coupling Between the Modeling and Controller-Design Problems—Part II: Design

In Part I of this paper, the coupling between the modeling and controller-design problems was quantified in terms of the size of the set of models from which satisfactory controllers may be derived. Herein, the significance of this coupling in controller design is exploited in the formulation of a simultaneous approach to modeling and controller design. The goal is to minimize the worst-case control effort subject to constraints on worst-case performance. It is proven that, by allowing the controller-design model and the controller to vary simultaneously, this approach yields a potential reduction in the control effort required to satisfy the prescribed performance goals in comparison to the traditional sequential approach. Two simple examples illustrating the benefits of this approach are also presented.