An Adaptive Fault-tolerant Robust Controller with Fault Diagnosis for Submarine's Vertical Movement

In this paper, an integrated design of fault diagnosis and adaptive fault-tolerant robust control for a submarine with bow and stern plane faults is proposed. Considering the disturbance coming from waves when a submarine operates near sea surface, a simplified linear system of submarine's vertical movement with both wave disturbance and bow and stern plane faults is presented. An unknown input observer is designed to decouple the wave disturbance and the bow and stern plane faults. Then a fault parameter tracking law is designed to estimate the bow and stern plane fault parameters without any prior fault information. Based on the estimated fault parameters, an adaptive robust fault-tolerant controller is designed. Simulation results show that the proposed control scheme has a satisfactory effect in the both pitch and depth control when the bow and stern planes suffer from unknown faults.