Predefined-Time Adaptive Fuzzy Control for a Class of Nonlinear Systems With Unknown Hysteresis

This article researches a predefined-time adaptive fuzzy tracking control problem for a class of nonlinear systems with unknown hysteresis. Unlike the previous investigations on predefined-time control, unknown input hysteresis is considered within this article. The existence of unknown input hysteresis leads to a control gain whose direction is unknown. The Nussbaum function is introduced to get over this difficulty. Lemma 8 is applied to ensure that an integral term with a Nussbaum function is bounded. Thus, the predefined-time stability criterion is ensured. Furthermore, an adaptive fuzzy control scheme is put forward. The proposed scheme guarantees that the tracking error is able to converge to the vicinity of the origin in an expected time. The practicability of the designed scheme is validated by an electromechanical system.