Adaptive Observer-Based Global Sliding Mode Control for Uncertain Discrete-Time Nonlinear Systems with Time-Delays and Input Nonlinearity

A new discrete-time adaptive global sliding mode control (SMC) scheme combined with a state observer is proposed for the robust stabilization of uncertain nonlinear systems with mismatched time delays and input nonlinearity. A state observer is developed to estimate the unmeasured system states. By using Lyapunov stability theorem and linear matrix inequality (LMI), the condition for the existence of quasi-sliding mode is derived and the stability of the overall closed-loop system is guaranteed. Finally, simulation results are presented to demonstrate the validity of the proposed scheme.