Indirect adaptive hierarchical fuzzy sliding mode controller for a class of nonlinear systems

This study presents a novel indirect adaptive hierarchical fuzzy sliding mode controller for a class of high-order SISO nonlinear systems with unknown function in the presence of bounded disturbance. The hierarchical fuzzy system is able to reduce the number of rules and parameters with respect to ordinary fuzzy systems. On-line tuning algorithm for consequent part parameters of fuzzy rules in different layer of hierarchical fuzzy system is derived using defined Lyapunov function. It is proved that the suggested adaptive scheme can achieve asymptotically stable tracking of a reference input with guarantee of the bounded system signals. To show the effectiveness of the proposed method, control of flexible joint robot system is considered in simulations. The simulation results demonstrate the validity, efficiency and feasibility of the proposed approach to control of nonlinear dynamic system.