Optimum response of discontinuous feedback control systems

THE CONCEPT of “optimum” lies at the heart of all sophisticated design work. The intelligent designer always wants to know which design meets a given set of conflicting conditions and constraints in the best possible, or optimum, way. This is especially true in feedback control system engineering, where, in order to describe optimum quantitatively, its meaning is narrowed to include only system performance characteristics. Usually a performance index is chosen, and the optimum system is defined as the system that minimizes (or maximizes) the performance index for the given set of constraints.