Command filtering-based adaptive backstepping control for a class of discrete-time uncertain nonlinear systems with mismatched disturbances

This paper investigates the adaptive fuzzy backstepping control problem for uncertain discrete-time nonlinear systems with mismatched disturbances. A novel adaptive fuzzy command filtered backstepping approach is proposed, which can overcome the noncausal problem by using the command filter. The filter errors generated by filter are removed by constructing error compensation mechanism. The fuzzy logic systems are used to approximate the uncertain nonlinear dynamics, and the unknown mismatched disturbances are actively attenuated by using adaptive control technique. Based on the proposed new weighed Lyapunov functions, all the signals in the close-loop system are proved to be uniformly ultimately bounded. The viability of proposed method is demonstrated by simulation results.