Observer based adaptive fuzzy sliding mode controller for MIMO nonlinear systems with general input matrix

In this paper a new observer-based adaptive fuzzy sliding mode (AFSM) controller is proposed for tracking control of a class of unknown multi-input multi-output (MIMO) nonlinear systems with general input matrix. The fuzzy system is used to approximate the ideal sliding mode controller. Also, a robust controller is designed to compensate the fuzzy estimation error. The bound of errors are adjusted adaptively. Unlike the previous works, in this paper the more general class of nonlinear MIMO systems are considered in which the subsystems of the plant are coupled through both states and inputs. The normalization factors are used for linear combination of fuzzy system outputs which are tuned adaptively. Adaptive laws are derived based on Lyapunov stability analysis, therefore asymptotic tracking and the stability are guaranteed. Numerical results show the efficiency of the proposed algorithm.