Thruster fault accommodation for underwater vehicles

This paper introduces a new approach associated with fault detection and accommodation for remotely operated underwater vehicles. The proposed fault detection and accommodation system (FDAS) consists of two subsystems: fault detection subsystem (FDS) and fault accommodation subsystem (FAS). The FDS uses fault detector units (FDU), associated with each thrusler, to monitor Iheir healthy slate. Robust and reliable fault detection units are based on integration of self-organising maps and fuzzy logic clustering methods. The FAS uses information provided by the FDS to accommodate faults and perform an appropriate reconfiguration. A control energy cost function is used as the optimisation criteria. In fault-free and faulty cases the FAS finds the optimal solution, which minimise this criteria. The feasible region concept, related with the problem of thruster velocity saturation, is described.