Researchers at Harvard’s Wyss Institute for Biologically Inspired Engineering have created a set of fish-shaped underwater robots that can autonomously navigate and find each other, collaborate on performing tasks or just calmly walk together in school.
Just as air drones are proving useful in industry after industry, underwater drones can revolutionize ecology, shipping and other areas where a sustained presence underwater is desirable but difficult.
The last few years there have been interesting new autonomous underwater vehicles or AUVs, but the most common type is basically a torpedo – effective for cruise open water, but not for working your way through nooks and crannies in a coral reef or marina.
To that end, it seems practical to see what Nature itself has seen fit to create, and the Wyss Institute has made a specialty in doing so and creating robots and machines in imitation of the natural world.
In this case, Florian Berlinger, Melvin Gauci, and Radhika Nagpal, all co-authors of a new paper published in Science Robotics, decided not only to mimic the shape of a fish, but also the way it interacts with its fellows.
Inspired by the sight of schooling fish while diving, Nagpal has pursued the question: “How do we create artificial agents that can demonstrate this kind of collective coherence, where an entire collective acts as if it were a single agent?”
Their answer, Blueswarm, is a collection of small “Bluebots”, 3D-printed in the shape of fish, with fins instead of propellers and cameras for the eyes. Although neither you nor I are likely to confuse these with actual fish, they are far less intimidating to an object that a normal fish can see than a six-foot metal tube with a propeller that rotates high at the rear. Bluebots also mimic nature’s innovation of bioluminescence and illuminate with LEDs, as some fish and insects do to signal others. The LED pulses change and adjust depending on each bot’s position and knowledge of its neighbors.
Using the simple senses from cameras and a photosensor at the front, elementary swimming movements and LEDs, Blueswarm automatically organizes itself into group swimming behaviors and establishes a simple “milling pattern” that accommodates new bots as they fall in from any angle.
The robots can also work together on simple tasks, such as searching for something. If the group is given the task of finding a red LED in the tank they are in, they can each see independently of each other, but when one of them finds it, it changes its own LED, which flashes to warn and summon them others.
It is not difficult to imagine applications for this technology. These robots could get closer to reefs and other natural features safely without alarming marine life, monitoring their health or looking for specific objects that their camera eyes could detect. Or they could be meandered around under docks and ships inspecting hulls more efficiently than a single vessel can. Maybe they can even be useful in search and rescue.
Research also promotes our understanding of how and why animals swarm together in the first place.
With this research, we can not only build more advanced robot collectives, but also learn about collective intelligence in nature. Fish need to follow even simpler behavior patterns when swimming in schools than our robots do. This simplicity is so beautiful, yet difficult to discover, ”said Berlinger. “Other researchers have already reached out to me to use my Bluebots as fish surrogates for biological studies of fish swimming and schooling. The fact that they welcome Bluebot among their lab fish makes me very happy. ”