A decade ago, industries that needed to perform underwater inspection and maintenance had only one option: send a human diver into the water. In both the military and commercial industries, the role of a skilled diver is critically important — but inherently risky. Despite the training and experience that these divers possess, accidents still happen, making a human diver's job one of the most dangerous in the world.

Today, many industries, the military included, are turning to robots to keep divers out of harm's way. Advances in computer vision and artificial intelligence are enabling robotic systems to perform tasks with human-like control. And when exploration must take place in deep waters deemed unsafe for the human body, robotics steps in.

The Evolution of Underwater Robotics

Developing robots that can move, see, and grasp objects underwater is not without its challenges. Varying lighting conditions, rapid currents, and turbid waters can affect the way a robot is controlled, how it moves, and what it is able to “see” underwater.

RE2 Robotics has been developing outdoor mobile manipulation systems for commercial and military customers for more than twenty years. In 2015, the company was awarded its first contract with the Office of Naval Research (ONR) to develop underwater robotic systems that mimic the dexterity and control of its ground-based robots. By 2018, the company developed and tested its first subsea system that was capable of remotely and effectively neutralizing waterborne improvised explosive devices (WBIEDs).

Since then, RE2's subsea technology has continued to evolve. In 2020, RE2 received additional funding from ONR to continue the development of its underwater system. During this phase, the RE2 team upgraded the system for deep ocean use, enabling it to descend deeper than its standard operating depth of 300 meters. It also applied its computer vision and machine-learning algorithms, RE2 Detect™ and RE2 Intellect™ to the system to enable autonomous manipulation capabilities. The system had been teleoperated up until then, and these upgrades were focused on providing Navy personnel with the ability to autonomously perform mine countermeasure (MCM) missions using supervised autonomy, which allows a human operator to provide oversight during the mission and intervene if necessary.

In 2021, RE2 branded its underwater robotic arms RE2 Sapien™ Sea Class. That same year, the company announced that it had received $9.5 million from ONR to create a robotic system for the autonomous neutralization of underwater mines for the U.S. Navy. This system, called the Maritime Mine Neutralization System (M2NS), uses RE2 Sapien™ Sea Class arms to precisely place and attach neutralization devices to underwater mines and WBIEDs.

“The detection and neutralization of WBIEDs and other underwater explosives is a critically dangerous task for Navy divers. Consistent with our mission of improving worker safety, the M2NS will enable the Navy to find and autonomously neutralize targets in deep ocean waters, while experienced divers supervise from a safe distance,” said Jorgen Pedersen, president and CEO of RE2 Robotics.

Underwater Autonomy Capabilities

The M2NS uses RE2 Detect and RE2 Intellect to enable the precise, autonomous, and clandestine neutralization of WBIEDs. RE2 Detect is perception software that can detect and track objects in just about any environment. RE2 Detect leverages multi-modal 2D and 3D imaging sensors and algorithms that can adapt to various lighting and environmental conditions. RE2 Intellect handles anomalies that are common in unstructured, outdoor environments, similar to the way human brains perceive and process information. Working together, RE2 Detect and RE2 Intellect provide human-like decision processing capabilities to control the RE2 Sapien Sea Class arms as well as the ROV of the M2NS.

With two symmetrical 7-function arms, RE2 Sapien Sea Class provides human-like dexterity in constrained underwater environments. The closed, sealed design of the RE2 Sapien Sea Class system protects the electrical system from water ingress and contamination.

“The M2NS uses RE2 Detect computer vision software to locate targets underwater, and RE2 Intellect to autonomously and precisely place devices on those targets,” said Dr. Amanda Sgroi, director of computer vision and autonomy at RE2. “We have also integrated new sensors to provide situational awareness and aid autonomy, allowing the system to navigate to extended depths in the ocean.”

Electromechanical Design

Along with RE2 Sapien Sea Class arms, M2NS uses VideoRay's Defender remotely operated vehicle (ROV), which both exhibit unprecedented power density. RE2 Sapien Sea Class arms feature a compact, strong, electromechanical design with human-like dexterity (7-functions per arm). The system is neutrally buoyant, which means that the system stays balanced and controllable at any depth — an essential feature when grasping objects. These features work together to provide superior strength and precision while manipulating neutralization devices. The design of RE2 Sapien Sea Class has been tested to withstand and counteract the corrosive effects of extended saltwater exposure, which corresponds to a longer service life.

Deep Ocean Testing

Over the past year, the company has successfully tested the autonomy capabilities of the RE2 Sapien Sea Class system in deep ocean water off the coast of San Diego.

Computer vision enables autonomous manipulation and aids navigation to extended depths.

“Although the Naval tasks cannot be publicly disclosed, the tasks demonstrated highly sophisticated capability analogous to non-military tasks, such as turning a valve, painting a surface, threading a pulley, and precisely inspecting seams,” said Pedersen.

In addition to the testing of its autonomy capabilities, the RE2 system recently reached an unprecedented depth milestone of 1 kilometer. During the test event, which took place in the Pacific Ocean with support from Naval Information Warfare Center Pacific in Point Loma, CA, four successful dives exceeding 1,000 meters of depth were completed.

The dives were conducted using supervised autonomy, which allows human operators to monitor the robotic system's autonomous movements and make corrections if necessary. All onboard electronics remained operational during the dives, including the ROV's camera feed and data to the support vessel, proving the survivability of the complete system to a depth of more than 1,000 meters.

RE2 Sapien Sea Class is designed with neutral buoyancy, ensuring that the system stays balanced and controllable at any depth.

“These tests allowed us to demonstrate the continuing success of the M2NS project for the U.S. Navy,” said Jack Reinhart, vice president of project management, RE2 Robotics. “The progress we made during these deep dives shows that we could successfully complete an underwater supervised autonomous mission at depths of more than 1,000 meters without any damage to the system. The M2NS system succeeded where no other system of this class has before.”

“We've proven the ability to deploy the Defender with a large payload to 1,000-meter depths from a small deck footprint,” said Marcus Kolb, chief technology officer, VideoRay. “We performed complex, autonomous manipulation tasks with the RE2 system while station keeping a few feet off the bottom. We are excited about the direction of this program and how it will help accelerate commercial solutions.”

M2NS is a lightweight, environmentally hardened underwater robotic system. Its small footprint and neutrally buoyant design allow it to access confined, precarious spaces that bulkier systems cannot, and enables it to perform tasks that are often identified as too dangerous, complex, or remote for humans.

In addition to defense tasks, the human-like capability of the M2NS allows it to be used for complex offshore infrastructure and maintenance applications in the oil & gas and renewable wind industries. For example, M2NS can be used for weld inspection of rig piles, ships and FPSO (Floating Production Storage and Offloading) systems; mooring inspection and measurement; and valve inspection and manipulation.

Advanced Control System

In addition to its work on the M2NS project, RE2 is also pioneering a new method of control for its underwater systems. The company recently announced that it has received U.S. Navy funding to develop a system that enables “coupled control” of an ROV and robotic manipulator through a single control system. The project, called Coupled Locomotion and Manipulation System (CLAMS), will combine the robotic arms’ control system and the ROV control system into one unit, improving coordination of the underwater manipulator and the ROV's movements.

CLAMS will also enable topside operators to control a system's robotic arms and ROV simultaneously using one control station by combining RE2's newly developed Coupled Remote Link Software (CTRLS) and the System Unification Model (SUM) to enable interoperability between ROV and robotic arm systems. CTRLS allows the topside ROV operator to send mission goals to the SUM module located on the vehicle. This enables the vehicle and robotic arms to quickly and efficiently achieve those mission goals, improving the ease of operators completing complex, underwater tasks.

“Currently, robotic arms and ROVs are controlled with separate control systems. CLAMS will enable both the robotic arms and the mobile platform to be operated with a single control unit,” said Pedersen. “Integrating these platforms will enable users to increase efficiency by eliminating the need for an operator to monitor two separate control stations while completing a mission.”

Looking Ahead

With the majority of the earth's surface covered in water, there is a need for robotic technology that can assist in the inspection and exploration of the world's oceans and waterways. From the inspection and neutralization of underwater mines for the U.S military to commercial industry maintenance tasks, underwater robotic systems across numerous industries are technology is finally available to deliver those capabilities.

This article was written by Jennifer Brozak, Director of Marketing, RE2 Robotics (Pittsburgh, PA). For more information, visit here .