Fixed-time adaptive fuzzy control for nonlinear interconnection high-order systems with  unknown control direction

Abstract This study investigates an adaptive fixed-time tracking problem of nonlinear interconnected high-order systems with unknown control direction and stochastic disturbances. By utilizing the Nussbaum gain technique, an adaptive fixed-time controller is proposed to overcome difficulties associated with unknown control directions. Under the framework of adaptive feedback, the backstepping method and fuzzy logic system are utilized to deal with the stochastic disturbances and the packaged unknown nonlinearities. Adding a power integrator is used within the adaptive backstepping control scheme to deal with the positive odd integer terms. The designed control strategy guarantees that the tracking error converges within a fixed settling time and all signals of the closed-loop system are fixed-time bounded. Simulation results validate the designed control approach.