Improving fault handling in marine vehicle course-keeping systems

Proposes a FDI algorithm that is tested by simulation of the rudder servosystem in the closed-loop course-keeping system for a Mariner Class vessel. A properly adjusted recursive extended least-squares (RELS) identification algorithm is utilized for fault-detection purposes, since hardly detectable faults (also called multiplicative faults) are handled. The rudder subsystem model, as a part of the overall closed-loop course-keeping system, is presented, and the three main parts of the proposed FDI module, which are configured on the basis of a RELS algorithm, are described. We show simulation results and provide comments for both linear and nonlinear (complete 3 degree-of-freedom model) Mariner Class vessel dynamics. We also discuss the connection to some other approaches and provide possible improvements for the suggested algorithm.