Adaptive fuzzy command filtered control for incommensurate fractional-order MIMO nonlinear systems with input saturation

In this paper, an adaptive fuzzy control approach for incommensurate fractional-order multi-input multi-output (MIMO) systems with unknown nonlinearities and input saturation is presented. First, the nonlinear terms of MIMO systems are identified by introducing the fuzzy logic systems, and an adaptive compensating control term is provided to estimate the approximation errors. Then, the drawback of "explosion of complexity " in the typical backstepping is effectively figured out via an improved command filter, and the influence of filtered error is avoided by constructing the error compensation laws. Meanwhile, the input saturation issue is addressed by utilizing the fractional-order auxiliary equations. Derived from the fractional-order Lyapunov stability theory, it is proved that all signals of the closed-loop system are guaranteed to be bounded. Finally, the availability of the investigated control scheme is verified by simulation examples.