Robust fixed-time fault-tolerant control for unmanned marine vehicles via integral terminal sliding mode technique.

In this paper, a novel fixed-time fault-tolerant control (FTC) scheme is proposed for unmanned marine vehicles (UMVs) with dynamics uncertainties and ocean disturbances. By introducing a high-order integral term, a fixed-time integral terminal sliding mode (ITSM) with faster convergence rate is proposed, which mitigates the effect of the initial system state on the convergence time successfully. Furthermore, based on the online estimation information from the adaptive mechanism, the effects of thruster faults, dynamics uncertainties, and ocean disturbances can be compensated by designing an adaptive fixed-time fault-tolerant controller. Compared to the existing results, the proposed FTC strategy ensures stability in a fixed-time framework. Finally, the comparison simulations of a floating production ship have demonstrated the efficacy of the proposed scheme. • A new fixed-time integral terminal sliding mode (ITSM) control strategy is designed for UMVs in this paper. Unlike our previous work in asymptotic convergence over an AISMC (Yu et al., 2022), the proposed FTC method can ensure fixed-time convergence. • A novel adaptive FTC strategy in the framework of fixed-time ITSMC is presented. Compared with existing result that neglected actuator faults (Qiao et al., 2018), the fault effect are taken into account. [ABSTRACT FROM AUTHOR]