ABSTRACT

Currently, pilots maximise the performance of Seaglider underwater gliders by selecting their set-up parameters. Building on existing procedures based on the assumption of steady-state motions, a recommender system for the trim and flight parameters is developed to aid trainee pilots and enable round-the-clock operations. The system has been validated with data from 16 missions run in waters off the United Kingdom and Australia. Whereas close agreement to the actual decisions by pilots is found for the trim parameters, the prediction of the flight parameters requires further smoothing.

INTRODUCTION

Underwater gliders (UGs) represent a type of autonomous underwater vehicles (AUVs) whose vertical motion is obtained through changes in their buoyancy and is converted into horizontal motion through wings (Rudnik, 2016). As a result, they move in a characteristic vertical zigzag pattern or profile. Although they move at slow velocities, their propulsion system, which consists only of a variable buoyancy device (VBD), roll and pitch control mechanisms and sometimes a rudder, is very efficient and as a result UGs may be deployed for months in an area of operation. Therefore, UGs are a fundamental tool for the study of the oceans. Not only are they used to study large-scale effects, e.g. boundary currents and the regional effects of climate variability, but also smaller scale effects like mesoscale and submesoscale features such as fronts and eddies (Rudnik, 2016). Thorough reviews of UG technology with a focus to oceanographic applications may be found in Davis, et al. (2003) and Rudnik (2016).

The National Oceanography Centre (NOC) in the UK operates a fleet of UGs for the study of the oceans, collaborating with the Scottish Association of Marine Sciences and the University of East Anglia. As part of the Oceanids project funded by the Industrial Strategy Challenge Fund, the NOC is developing a new command-and-control system for efficient marine autonomous systems fleet management. The aim of the system is to facilitate the operation of the ever-increasing fleet of AUVs. As part of this work, a recommender system for the selection of the trim and flight parameters of UGs is highly desired. The system would return recommended values to the pilots within the fleet management software. However, pilots would be still able to overwrite the system so that it would not represent fully autonomous operation. Initially, the recommender system may help trainee pilots to determine the correct set-up of UGs. Once the system has been proven to be effective and robust, it may be used during night time and to help expert pilots track the operation of multiple UGs.

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