Optimal model-following control-system synthesis techniques

The paper considers three control-system-synthesis methods in which optimisation techniques are used to design controllers that make the closed-loop system behave like a specified ideal system or model. The necessary background theory is summarised, and the techniques of real and implicit model-following are discussed, especially their practical and computational aspects. A simpler algebraic form of the implicit-model-following performance criterion is presented. It is shown that, provided certain conditions are satisfied, this formulation yields a control law that is easily computed, unique, and useful in practical problems.