Adaptive control of MIMO nonlinear systems with disturbances and time delays

Based on the principle of sliding mode control, an adaptive control scheme is proposed for a class of multi-input multi-output (MIMO) nonlinear time-varying delay systems with unknown dis urbances. Neural networks are used to approximate the unknown nonlinear functions. By choosing appropriate Lyapunov-Krasovskii functionals, unknown time-varying delay uncertainties are compensated for. By utilizing the integral-type Lyapunov function and Young´s inequality, the restrictions of the control gain and the assumptions of time-varying delay uncertainties are relaxed. By theoretical analysis, it is shown that all the signals in the closed-loop system are uniformly ultimately bounded. Finally, simulation results are provided to illustrate the effectiveness of the proposed approach.