Synthesis of variable gain robust controllers based on point memory LQ regulator for a class of uncertain time-delay systems

This paper proposes a design method of a variable gain robust controller based on point memory feedback for a class of uncertain time-delay systems. The proposed variable gain robust controller consists of a fixed gain controller derived by using the nominal time-delay system and a variable gain one, and the fixed gain controller is a point memory LQ regulator. In this paper, we show that sufficient conditions for the existence of the proposed variable gain robust controller are given in terms of LMIs. Finally, a simple numerical example is included to show the effectiveness of the proposed robust control system.