Review on fault-tolerant control of unmanned underwater vehicles

Unmanned underwater vehicles (UUVs) are invaluable tools for ensuring the safety and efficiency of marine activities and have shown exceptional potential in resource exploration, underwater facility construction, and seafood fishing. However, unpredictable and complex underwater environments pose significant risks to UUVs, making them susceptible to faults that threaten their motion reliability and system safety. Fault-tolerant control (FTC) techniques have been developed to improve the system robustness and provide acceptable performance in the presence of faults, thereby enhancing their reliability and safety. This study conducts a comprehensive analysis and provides a summary of the latest UUV-FTC research spanning 1999-2022, covering actuators, sensors, and cooperative systems. FTC for actuating systems is classified into multi-model reconfiguration, actuator thrust reconfiguration, and thrust reallocation. Additionally, this study explores fault-tolerant strategies (FTSs) for sensors that leverage physical or analytical redundancies to reproduce or correct sensor signals. Furthermore, the study addresses FTCs for multi-UUV cooperation systems, focusing primarily on issues related to consensus, containment, and formation under actuator or communication-link faults. Finally, the unresolved scientific issues are discussed to inspire future research. The UUV-FTC review presented a complementary perspective by revealing both the shared characteristics and unique aspects, which have not been addressed in existing FTC reviews.