Researchers are developing underwater robots capable of communicating via acoustic signals to form the basis of the future underwater Internet of Things.
Part of the EU-funded project Sunrise, working prototypes have recently been tested in Portugal with scientist proving the robots can communicate in the aquatic environment and respond to instructions sent to them from the ground as designed.
While communication between smartphones, computers and other gadgets or machines using radio waves is already perfectly mastered, the underwater environment presents its very specific set of challenges. The main obstacle in underwater communication is that radio waves don’t propagate in water and acoustic waves only do so to a limited extent.
However, the scientists are certain that once that issue is solved, the benefits for mankind could be enormous.
‘The gaps in our knowledge of the underwater world are extensive. We know so little despite the fact that marine ecosystems are central to the health of our planet and vital to our economies,’ said Chiara Petrioli, leader of the Sunrise project.
To enable shoals of underwater robots to work together to monitor gas pipelines, examine submerged archaeological sites or study marine geology, researchers are developing a communication system resembling that of dolphins and whales.
By transmitting acoustic waves of specific frequencies, they were able to send commands to the robots, albeit at rather slow rates. However, the limitations are many. Sound waves in water not only travel five orders of magnitude slower than radio waves in the air, theyare also easily disrupted by the morphology of the terrain or water currents. Moreover, only a relatively limited range of frequencies could be used as high tones don’t get very far.
“Salinity, temperature, interference in the form of waves or passing ships, all these will change the range of effective communication,” Petrioli explained.
This unpredictability of the submarine environment is one of the key reasons why the underwater Internet of Things remains such a challenge compared to the land-based WiFi-connected systems. To be able to promptly respond to the changing conditions, the robots had to be carefully programmed.
The team believes that employing larger shoals of underwater robots could help solve some of the problems. If one of the robots is momentarily unable to communicate, others in the shoal could cover for it. Shoals of robots could also carry a greater number of sensors and cover a larger area, while communicating and cooperating together.
The multinational project involves partners from Italy, Germany, Portugal, Netherlands, Turkey and the United States.
“This is the biggest scale endeavour in this field, globally,” Petrolli said. “We are putting Europe at the frontier of this type of work.”
The researchers hope to test their prototypes in other marine environments. After the warm water of the Mediterranean Sea, they would like to move to the colder Baltic Sea, fresh water lakes in the Netherlands or Atlantic and Pacific coast of the US.