Uniformly asymptotical stability of nonlinear time delay systems

This paper deals with the problem of uniform stability and asymptotical stability for nonlinear time delay systems. Some new sufficient conditions are established guaranteeing uniformly stability and asymptotical stability, which show that the derivative of the Lyapunov function relaxes to be indefinite instead of negative definite in the literature. A result for determining input to state stability of nonlinear time delay systems is also reported in this paper.