Sensor failure detection and isolation for control system of underwater vehicle

By means of concept of direct redundancy, the method of sensor fault detection and isolation (FDI) during motion of the underwater vehicle was proposed. The method of sequence probability ratio testing (SPRT) was introduced. The faults were inspected by sequence probability ratio between two hypotheses through surveying of residue in each time, in which the residue was defined as the difference of output of the sensor and estimated value obtained by analytical expression among outputs of the other sensors. The residue expressions for each gyro sensors were given. The procedure and decision logic of the FDI were presented. The simulation results have shown that the proposed method is effective, which applies to FDI for large range of maneuver process of the underwater vehicle.