This paper reports our results in using a discrete fault diagnosis system, Livingstone 2 (L2), on-board an autonomous underwater vehicle (AUV), Autosub 6000. Due to the difficulty of communicating between an AUV and its operators, AUVs can benefit particularly from increased autonomy, of which fault diagnosis is a part. However, they are also restricted in their power consumption. We show that a discrete diagnosis system can detect and identify a number of faults that would threaten the health of an AUV, while also being sufficiently lightweight computationally to be deployed on-board the vehicle. Since AUVs also often have their missions designed just before deployment in response to data from previous missions, a diagnosis system that monitors the software as well as the hardware of the system is also very useful. We show how a software diagnosis model can be built automatically that can be integrated with the hardware model to diagnose the complete system. We show empirically that on Autosub 6000 this allows us to diagnose real vehicle faults that could potentially lead to the loss of the vehicle.More
Advanced AUVs that are capable of long duration missions are becoming increasingly common. However, making the vehicles reliable is a significant challenge, and fault detection has an important role to play in achieving this. To enhance the state of the art we present the data of a selection of Autosub 6000 missions. The data is given in DXC format with known faults injected into the logs.More
This paper addresses the problem of low cost actuator fault detection, diagnosis and accommodation for Remotely Operated Vehicles. The research is based on the analysis of the telemetry of Romeo, the overactuated ROV developed by C.N.R.-I.A.N., operating both in nominal and different failure conditions. Results demonstrate how the monitoring of the servoamplifiers’ I/O variables enables the detection and diagnosis of actuator faults for operating ROVs, supporting the pilot in making decisions on the realtime reconfiguration of the propulsion system. The integration of the servo-level FDDA module with a conventional navigation, guidance and control system is discussed. On the basis of experienced time-varying effects of operating failures, suitable models of the damaged actuators and algorithms for the generation of fault symptoms and alarms have been designed, implemented and satisfactorily tested on a large
amount of recorded ROV data. The conventional fault accommodation procedure based on the reconfiguration
of the vehicle’s thrust control matrix has been applied. The capability of Romeo of working in a reduced actuation configuration has been operationally demonstrated executing shallow water benthic missions for scientific users.
Autonomous underwater vehicle technology continues to advance at a rapid pace. REMUS (Remote Environmental Monitoring UnitS), developed by the Oceanographic Systems Laboratory at the Woods Hole Oceanographic Institution, is one of the most widely used autonomous underwater vehicles in the world. Each year REMUS vehicles participate in numerous field exercises in support of scientific and navy research objectives. Designed for coastal operations, REMUS is normally deployed with a CTD, light scattering sensor, side scan sonar and an up-and-down looking acoustic doppler current profiler (ADCP). Additional sensors are easily integrated in the vehicle and a bioluminescence instrument and a turbulence sensor package. Recent development efforts have improved the REMUS vehicle overall design and performance, and include integration of two new sensors. Vehicle improvements include lower drag, a new propulsion, new lithium-ion batteries and a new external interface. Maximum speed has been increased from 1.75 m/s to almost 3 m/s (6 knots) and mission length has increased to 22 hours at the 1.5 m/s (3 knots) cruising speed. REMUS has been used to demonstrate a new autonomous underwater vehicle application: plume mapping. A rhodamine fluorometer was installed to map a plume on a steep sloping sea floor. Results from the field test demonstrate the effectiveness of an AUV as a tool in this task. A second REMUS vehicle has been deployed with an optical sensor package. The instruments in the package include a chlorophyll fluorometer and up-and-down looking, seven channel radiometers. This package combined with the standard CTD and ADCP generates a significant scientific data set, which supports both physical and biological oceanographic researchMore