Adaptive fixed-time fault-tolerant fuzzy control of AUVs with asymmetric output constraints

Abstract

The fast and safe formation tracking problem for multiple autonomous underwater vehicle (AUV) systems (MAUVS) with asymmetric output constraints and actuator faults is studied in this article. Actuator faults are composed of loss of effectiveness and time-varying unknown bias faults, an adaptive fixed-time fault-tolerant controller (AFFTC) is designed by employing fixed-time stable theory and fuzzy logic systems. Under the designed control algorithm, the MAUVS can be practically fixed-time stable, the tracking errors among the follower AUVs and the virtual leader AUV can converge to a small area near the origin within the fixed time, and the settling time is unaffected by the initial state of the system. To enhance the safety of MAUVS, a novel asymmetric barrier function is utilized to constrain the trajectory tracking errors within the prescribed range. Finally, the simulation results demonstrate the effectiveness of the proposed control algorithm.