Bubble Plume Tracking Using a Backseat Driver on an Autonomous Underwater Vehicle

Abstract

Autonomous underwater vehicles (AUVs) have been applied in various scientific missions including oceanographic research, bathymetry studies, sea mine detection, and marine pollution tracking. We have designed and field-tested in the ocean a backseat driver autonomous system for a 5.5 m survey-class Explorer AUV to detect and track a mixed-phase oil plume. While the first driver is responsible for controlling and safely operating the vehicle; the second driver processes real-time data surrounding the vehicle based on in situ sensor measurements and adaptively modifies the mission details. This adaptive sensing and tracking method uses the Gaussian blur and occupancy grid method. Using a large bubble plume as a proxy, our approach enables real-time adaptive modifications to the AUV’s mission details, and field tests show successful plume detection and tracking. Our results provide for remote detection of underwater oil plumes and enhanced autonomy with these large AUVs.

Adaptive AUV Mission Control System Tested in the Waters of Baffin Bay

“…This work extended our previous research, where we extensively examined three different sonars, each with a distinct frequency, against oil droplets and gas bubbles in a wave tank, along with micro air bubbles (100 to 500 microns) in a local lake [15]. Additionally, we conducted further tests using the Ping360 sonar against micro air bubbles (<100 microns) in an open ocean setting [16], and in a towing tank against micro air bubbles (100 to 250 microns) [17]. These tests assessed the detection capability and performance of the selected sonar in capturing micro air bubbles, closely resembling the acoustic features of oil droplets.…”

“…The trials were designed to collect acoustic data of a micro air bubble plume, which was used as an acoustically similar, environmentally friendly proxy for an oil plume. The plume was created by a bubble generator [16], and the Explorer AUV executed a lawnmower mission around the generator's submerged discharge nozzle. The Ping360 scanning sonar mounted on the Explorer AUV continuously scanned a 120 0 sector on the To fortify our adaptive system's capabilities, we implemented a Backup Opinion Strategy (BOS) as a contingency plan to address potential limitations during the Search module, particularly when the Ping360 sonar was active yet unable to detect any sign of a hydrocarbon plume.…”

“…The trials were designed to collect acoustic data of a micro air bubble plume, which was used as an acoustically similar, environmentally friendly proxy for an oil plume. The plume was created by a bubble generator [16], and the Explorer AUV executed a lawnmower mission around the generator's submerged discharge nozzle. The Ping360 scanning sonar mounted on the Explorer AUV continuously scanned a 120 0 sector on the port side of the vehicle during the mission.…”