Field Validation of Novel Low-Cost Underwater Robot for Deepwater Exploration and Characterization

Past Expedition

Primary Goal

Improve/develop low-cost, open-source, autonomous underwater vehicles and automatic annotation software

Dates

August 14-18, 2023
June 30-July 3, 2025

Location

Atlantic Ocean, Near Key Biscayne Florida; Florida Keys (Year One)
Pacific Ocean, Makapu‘u Precious Coral Bed off Oahu, Hawai‘i (Year Two)

Vessel

Research Vessel Dewey Dewayne, Research Vessel Bond (Year One)
MANAO II (Year Two)

Primary Technology

Hybrid remotely operated vehicle/autonomous underwater vehicle
Autonomous underwater vehicle

Project Summary (Year One)

As part of an effort to help protect deep-sea coral ecosystems, a team of engineers and scientists have been developing two low-cost, open-source, underwater vehicle systems for the survey and classification of deep-sea corals. From August 14 to 18, 2023, they successfully tested these systems and collected data at natural and artificial reefs near Key Biscayne, Florida, and in the Florida Keys known for their high diversity and density of corals, including Emerald, Rainbow, Conch, and Eagle reefs.

The DROPSphere autonomous underwater vehicle (AUV) and the hybrid remotely operated vehicle (ROV)/AUV Bruce were the stars of this project. Compact and custom-built using off-the-shelf parts, these underwater vehicles are deployable by a single operator, affordable, and open source.

Locations of fieldwork during Field Validation of Novel Low-Cost Underwater Robot for Deepwater Exploration and Characterization. — Locations of fieldwork during Field Validation of Novel Low-Cost Underwater Robot for Deepwater Exploration and Characterization in 2023. *Image courtesy of Field Validation of Novel Low-Cost Underwater Robot for Deepwater Exploration and Characterization.*
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Low-cost underwater robots for deepwater exploration: DROPSphere autonomous underwater vehicle (left) and Bruce hybrid remotely operated vehicle/autonomous underwater vehicle (right). — Low-cost underwater robots for deepwater exploration used during Field Validation of Novel Low-Cost Underwater Robot for Deepwater Exploration and Characterization: DROPSphere autonomous underwater vehicle (left) and Bruce hybrid remotely operated vehicle/autonomous underwater vehicle (right). *Image courtesy of Field Validation of Novel Low-Cost Underwater Robot for Deepwater Exploration and Characterization.*
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Team members with DROPSphere (left) and Bruce (right) underwater vehicles. — Team members with DROPSphere (left) and Bruce (right) underwater vehicles during Field Validation of Novel Low-Cost Underwater Robot for Deepwater Exploration and Characterization in 2023. *Image courtesy of Field Validation of Novel Low-Cost Underwater Robot for Deepwater Exploration and Characterization.*
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Project Summary (Year Two)

During their second and final year of fieldwork, this team of engineers and scientists tested two low-cost underwater vehicles during shore-based day operations at the Makapu‘u Precious Coral Bed, a federally protected deepwater habitat off the east coast of Oahu, Hawai‘i. Despite significant technical setbacks, they collected seafloor imagery, gained valuable insights for further vehicle development, and provided important hands-on learning for undergraduate students.

Satellite view of O'ahu, Hawaii, showing terrain, roads, and a red location marker.

Location of fieldwork during Field Validation of Novel Low-Cost Underwater Robot for Deepwater Exploration and Characterization in 2025. Image courtesy of Field Validation of Novel Low-Cost Underwater Robot for Deepwater Exploration and Characterization. Download largest version (jpg, 106 KB)

The Vehicles

The team’s primary objective was to continue evaluating the DROPSphere autonomous underwater vehicle (AUV) and hybrid remotely operated vehicle (ROV)/AUV Bruce with the goal of demonstrating that affordable robotic platforms can support long-term monitoring and research in sensitive and remote marine environments. Specifically, they aimed to assess the vehicles’ imaging capabilities, navigation precision, and operational reliability in challenging oceanic conditions.

Bruce remained unchanged since the previous fieldwork in 2023, but several upgrades had been made to the DROPSphere system, including a new microcontroller, onboard computers, and thrusters.

Yellow DROPSphere AUV floating on blue ocean water.

DROPSphere autonomous underwater vehicle (AUV), a custom-built AUV equipped with cameras to record seafloor images and/or video, during Field Validation of Novel Low-Cost Underwater Robot for Deepwater Exploration and Characterization in 2025. Image courtesy of Field Validation of Novel Low-Cost Underwater Robot for Deepwater Exploration and Characterization. Download largest version (jpg, 728 KB).

Yellow hybrid ROV floating in deep blue ocean with a tethering cable.

Bruce hybrid remotely operated vehicle (ROV)/autonomous underwater vehicle, a custom-built vehicle developed for deepwater operations, operating in ROV-mode during Field Validation of Novel Low-Cost Underwater Robot for Deepwater Exploration and Characterization in 2025. Image courtesy of Field Validation of Novel Low-Cost Underwater Robot for Deepwater Exploration and Characterization. Download largest version (jpg, 789 KB).

Challenges and Successes

The team deployed both vehicles, but testing was hampered by internal leaks on both as well as thruster failure on DROPSphere and damage to the fiber-optic tether on Bruce, the latter which occurred during transit to Hawai‘i. Unfortunately, Bruce could not be repaired in the field and was thus unusable.

While the team was unable to explore deepwater coral reefs, they were able to use DROPSphere to explore and collect visual footage of shallow water coral reefs.

Two individuals on a boat managing tethers for underwater vehicles, with the ocean and cloudy sky in the background.

Mikhalib Green and Richard Ray managing tethers for the underwater vehicles during Field Validation of Novel Low-Cost Underwater Robot for Deepwater Exploration and Characterization in 2025. Image courtesy of Field Validation of Novel Low-Cost Underwater Robot for Deepwater Exploration and Characterization. Download largest version (jpg, 516 KB).

The experience underscored the inherent difficulties of operating underwater vehicles, emphasizing that no matter how thoroughly one prepares, things may not go as planned and that each deployment should be approached with deep respect for the marine environment. Despite the challenges encountered, the experience provided valuable insights that will inform improvements to the vehicles. Additionally, the fieldwork served as an excellent hands-on learning opportunity for the undergraduate students involved, offering them meaningful exposure to real-world conditions and the complexities of ocean robotics.

Future Plans

In the coming months, the team will use artificial intelligence developed by the team to process and analyze the imagery collected during fieldwork and begin to rebuild the vehicles to address the damage they sustained during travel and deployment. They remain optimistic, and during the rebuilds they will identify design enhancements to improve the reliability and performance of the vehicles with the ultimate goal of drastically increasing the scope and economic efficiency of collecting ocean exploration data.