New delay-dependent stability criteria and robust control of nonlinear time-delay systems

This paper investigates the stability analysis and H∞ control for a class of nonlinear time-delay systems, and proposes a number of new results. Firstly, an equivalent form is given for this class of systems by means of coordinate transformation and orthogonal decomposition of vector fields. Then, based on the equivalent form, some delay-dependent results are derived for the stability analysis of the systems by constructing a novel Lyapunov functional. Thirdly, the authors use the equivalent form and the obtained stability results to investigate the H∞ control problem for a class of nonlinear time-delay control systems, and present a control design procedure. Finally, an illustrative example is given to show the effectiveness of the results obtained in this paper. It is shown that the main results of this paper are easier to check than some existing ones, and have less conservatism.