Delay-dependent H∞ control for linear systems with time-varying delayed state

Using the method of linear matrix inequalities (LMI), H_∞ controller is designed for linear system with time-varying delayed state. Both memoryless H_∞ state feedback control and observer-based H_∞ output feedback control are discussed for system analysis and synthesis. Sufficient conditions for feedback controller design are given by using two forms: the first is pure H_∞, state feedback controller, and the second is H_∞ dynamic output feedback controller. Both forms are delay-dependent. Two illustrative examples are given to show the applicability of the proposed approach.