Robust tracking control design for fractional-order interval type-2 fuzzy systems
Abstract In this paper, a robust control strategy is proposed to deal with the state tracking problem of fractional-order interval type-2 fuzzy system with external disturbance, model uncertainties and state delay. In particular, footprints of uncertainty of the underlying fuzzy system is taken into account to capture and model different level of uncertainties. The uncertainty and disturbance estimator is used to promote the tracking behavior of rejecting disturbance in the control system. First, by applying Lyapunov approach, we focus on the examination of stability and performance of the fractional-order tracking error system. Next, unknown system uncertainties, external disturbances and nonlinearities are accurately estimated via an appropriate filter design. Especially, the proposed control technique does not require any prior knowledge about above said unknown factors and it only require the bandwidth information about low-pass filter.Finally, the feasibility and advantages of the proposed design scheme are confirmed by three numerical examples.
