On the reliability of the Autosub autonomous underwater vehicle

As autonomous underwater vehicles (AUVs) enter operational service, an assessment of their reliability is timely. Using the Autosub AUV as an example, several design issues affecting reliability are discussed, followed by an analysis of recorded faults. Perhaps contrary to expectations, failures rarely involved the autonomous nature of the vehicle. Rather, faults were typical of those that occur with any complex item of marine electromechanical equipment. Reliability under various operating conditions was assessed using Weibull parametric models. This reliability modelling was extended to the case of a vehicle operating under ice in order to estimate the probability of loss in situations where the support vessel could not gain access to a malfunctioning vehicle.