Soft, underwater robots can help study sea creatures

Washington, August 2

Scientists have developed a soft, flexible underwater robot that can gently grab different types of organisms from the sea and study them without inflicting any damage.

The device can even add 3D-printed modifications to itself without the need to return to a land-based laboratory.

The deep ocean is notoriously inhospitable to humans, yet it teems with organisms that manage to thrive in its harsh environment.

Studying those creatures requires specialised equipment mounted on remotely operated vehicles (ROVs) that can withstand those conditions in order to collect samples.

This equipment, designed primarily for the underwater oil and mining industries, is clunky, expensive, and difficult to maneuver with the kind of control needed for interacting with delicate sea life.

Picking a delicate sea slug off the ocean floor with these tools is akin to trying to pluck a grape using pruning shears.

Scientists from Harvard University in the US have developed an alternative sampling device that is soft, flexible, and customisable, allowing scientists to gently grab different types of organisms from the sea without damaging them.

“When interacting with soft, delicate underwater creatures, it makes the most sense for your sampling equipment to also be soft and gentle,” said Rob Wood, from the Harvard John A Paulson School of Engineering and Applied Sciences (SEAS).

“It’s only recently that the field of soft robotics has developed to the point where we can actually build robots that can grasp these animals reliably and harmlessly,” said Wood.

The ‘soft gripper’ devices have anywhere from two to five ‘fingers’ made of polyurethane and other squishy materials that open and close via a low-pressure hydraulic pump system that uses seawater to drive their movement.

The grippers themselves are attached to a wooden ball that is held and manipulated using an ROV’s existing, hard claw-like tools, controlled by a human operator on the ship to which the ROV is tethered.

The soft grippers were able to grab sea slugs, corals, sponges, and other marine life much more effectively and with less damage than traditional underwater sampling tools.

Based on input from the ROV operators, the team 3D-printed ‘fingernail’ extensions that could be added to the gripper’s fingers to help them get underneath samples that were sitting on hard surfaces.

A flexible mesh was also added to each finger to help keep samples contained within the fingers’ grip.

Another, two-fingered version of the grippers was also created based on ROV pilots’ familiarity with controlling existing two-fingered graspers, and their request that the two fingers be able to hold samples with both a ‘pinch’ grasp (for small objects) and a ‘power’ grasp (for large objects).

The team is continuing to develop the grippers, hoping to add sensors that can indicate to the ROV operator when the grippers come into contact with an organism, feel how hard or soft it is, and take other measurements.

Ultimately, their goal is to be able to capture sea creatures in the deep ocean and obtain full physical and genetic data without taking them out of their native habitats. — PTI