Fixed-time adaptive fuzzy command filtering control for a class of uncertain nonlinear systems with input saturation and dead zone

In this article, the problem of fuzzy adaptive fixed-time control is addressed for nonstrict-feedback nonlinear systems with input saturation and dead zone. The universal approximation properties of fuzzy logic systems are employed to model the unknown nonlinear functions. A command filter-based fixed-time adaptive fuzzy control strategy is presented based on the backstepping framework and fixed-time control theory. The command filter technique is presented to address the "computational explosion" problem inherent in the backstepping scheme, and an error compensation mechanism is adopted to reduce the errors arising from command filters. Meanwhile, the non-smooth input saturation and dead zone nonlinearities are approximated using a non-affine smooth function, and they are transformed into an affine form based on the mean-value theorem. The fixed-time convergence of the tracking error and the boundedness of the closed-loop signals are proved using the fixed-time stability theory. Finally, simulation was performed to demonstrate the effectiveness of the presented method.