Further results on adaptive robust control of uncertain time-delay systems

The problem of adaptive robust control for uncertain systems with multiple time delays is considered. The parameter uncertainties are assumed to be time-varying norm-bounded, whose bounds are unknown. The objective is to design adaptive robust state-feedback controllers such that the resulting closed-loop system is globally uniformly exponentially convergent to a ball with a certain convergence rate. In terms of a linear matrix inequality, a sufficient condition for the solvability of this problem is presented and the expression of a desired adaptive robust state-feedback controller is given. It is shown that the result obtained improves certain existing ones in the literature.