For the first time, fully independent underwater robots have successfully removed a plastic bottle from the seabed. This is the first step to cleaning up a lot more waste.
The robot system was made by researchers from TU Delft, among others. It is intended to efficiently and safely clean up waste from the seabed. The robot was thrown into the deep sea for a test in the sea near Croatia, and passed with flying colors.
The amount of waste in the oceans is difficult to determine. It is estimated that 26 to 66 million tons can be found, of which about 94 percent is on the sea floor. All that plastic has major consequences for animals that get trapped in it, and for the environment if, for example, plastic particles dissolve in the water.
Projects such as The Ocean Cleanup that try to clean up floating plastic are therefore only part of the solution. The scant efforts now being made to remove the sunken debris come from divers. This mainly happens in tourist areas. Human divers are good at spotting and picking up the debris, but it’s an arduous and sometimes dangerous task.
Search and fish
That’s why . develops the SeaClear project robots that can take over this task. The system consists of two underwater robots, an accompanying ship and a drone. ‘One robot scans the seabed and detects where waste is’, says Bart de Schutter, professor at the Delft Center for Systems and Control. ‘He then passes this information on to the second robot, which has a sort of gripper and can pick up the waste.’ Both robots are attached to the ship with long lines for communication and power supply.
The drone contributes by searching for waste on the seabed from the air. If the water is clear, this is done via direct detection. In other cases, he looks at where floating plastic moves through the current, says De Schutter. ‘That often gives an indication of where there is also a lot of waste on the seabed.’
The detective robot works independently. Image recognition techniques trained by artificial intelligence allow him to recognize and distinguish waste from fish, plants and other marine life that he should leave alone.
Underwater robots in the Croatian sea
The waste disposal system was tested in September in the sea off the island of Lokrum, near Dubrovnik in Croatia. That’s a tourist spot that’s at the top of the researchers’ list for cleaning once the SeaClear system is up and running. In the clear water, the tracking robot successfully detected its first piece of litter: a plastic bottle.
The researchers will further improve the system in the coming period. ‘First of all, there is the size and weight of the objects that can be picked up,’ says De Schutter. ‘The underwater robots are now limited to objects of up to ten kilograms. That means that cleaning up a heavy car tire is not yet possible.’
Furthermore, they will improve image recognition and combine it with sonar, so that the clearing system works even in poor visibility. De Schutter: ‘In two years’ time we want to start working in Hamburg, for example, where the water contains a lot of sand and mud.’