Abstract
This paper aims to give a theoretical foundation to the ideal closedloop properties of high gain feedback systems, such as complete desensitization, complete tracking performance and complete disturbance rejection, which have been so far explained only heuristically in most text books of control theory. A synthesis method of high gain controller for single input single output plants is proposed based upon closed-loop root loci assignment, which achieves the ideal closed-loop performance mentioned above asymptotically. The method is extended to non-minimal phase plants via a cascade decomposition of the plant into the minimal phase part and the maximal phase part. This is shown to be a generalization of the celebrated design method by Smith for plants with dead time. Some numerical examples are shown to demonstrate the actural performance of high gain feedback systems.
