Delay-dependent robust H/sub /spl infin// control of uncertain linear systems with lumped delays

A linear matrix inequality approach to the robust H/sub /spl infin// control problem of uncertain continuous- and discrete-time linear time-invariant systems with time delay in the state vector and control input is developed. The main results provide sufficient delay-dependent conditions for the control problem, where the explicit size of the time delay plays a crucial role for the closed-loop stability. The solutions that are found for the H/sub /spl infin// control problem are less conservative when compared with other approaches in the recent literature.