Researchers and scientists are always looking for new ways to research deep-sea animals, without permanently removing the animals from their environment. This type of study requires special equipment that is perched on a remotely operated vehicle (ROV). The equipment needs to be durable enough to maintain operation under immense deep-sea pressure. A team has created a soft, flexible and customizable sampling device that allows researchers to collect different types of organisms without harming them or removing them completely from their environment.
A three-finger soft manipulator grasping a sea anemone attached to a rock on a hard substrate. (Source: Schmidt Ocean Institute)
The new device allows for easy modification. Researchers can 3D print modifications for the new device on the boat without having to return to land. This allows researchers to quickly and easily adjust the device depending on any issues they come across as they are doing their research.
The devices have two to five fingers. These fingers are made of polyurethane and other squishy materials. The fingers open and close through a low-pressure hydraulic pump system that uses seawater to drive the movement. The grippers are attached to a wooden ball that is held and manipulated with the ROV's tools and controlled by a human operator on the ship.
Researchers tested their new device on the R.V. Faulkner, a ship in the Phoenix Island Protected Area in the South Pacific. They brought two 3D printers with them on the ship so they could adjust the device and easily create new pieces if something were to break on the robot.
"By 3D printing at sea, we can innovate, on-the-fly, and come up with soft robotics to interact with soft and delicate animals that were previously unexamined - as they were too fragile," said David Gruber, presidential professor of biology and environmental science at the City University of New York's Baruch College and 2017-2018 Radcliffe Fellow and National Geographic Explorer.
"Being on a ship for a month meant that we had to be able to make anything we needed, and it turns out that the 3D printers worked really well for doing that on the boat. We had them running almost 24/7, and we were able to take feedback from the ROV operators about their experience using the soft grippers and make new versions overnight to address any problems," said Daniel Vogt, a research engineer at the Wyss Institute.
The soft gripper device gathered sea slugs, corals, sponges and other marine life while on the month-long research trip. The researchers could prove that it was more effective and less damaging to the animals than the traditionally used methods.
While on the research trip, the team 3D printed “fingernail” extensions that allow the fingers to get under samples that were sitting on hard surfaces underwater. They also added a flexible mesh to the fingers that helped the samples stay in the grip of the device.
The two-finger grasper was developed because the researchers have had previous experience with pinching devices. The samples were held in the hands of the device with either a pinching grasp for small samples or power grasp for larger objects.
The grippers are still being developed. The research team is working on adding sensors to the device to indicate when the grippers come into contact with an object, feeling how soft or hard the object is and more information.
The ultimate goal for the device is to capture sea creatures in the deep ocean to obtain full physical and genetic data from the animal without completely taking it out of its environment.
An upcoming paper on the newly developed device will be published in PLOS One.
