Sliding mode control of uncertain time-delay systems

Sliding mode control synthesis is developed for a class of nonlinear time-delay systems. The corresponding free-delay system is assumed to be controllable whereas no stability assumptions are imposed on the open-loop system. The synthesis is based on a new delay-dependent stability criterion. The controller constructed proves to be robust against sufficiently small delay variations and external disturbances. An admissible upperbound such that the corresponding closed-loop system remains globally asymptotically stable for all delay values less than this upperbound is derived.