Robot fish can communicate directly with each other under water

In the robot world that operates under water, robotic fishes belong to the robot group. While most ocean robots require periodic communication with scientists or intermediate satellites to share information, these robotic fishes can communicate collaboratively.

For the past 5 years, Kristi Morgansen, a professor of aerodynamics and astronautics at Washington University, has built three Robofish that can communicate with each other underwater. Recently, at the International Federation Meeting on Automatic Control in the field of orientation, guidance and control of underwater equipment, she presented the results showing that these robots have completed the test. The first major investigation was very successful. Programmed robots all swim in one direction or in different directions, basic tasks that can form obstacles to moving in line.

Success in testing in indoor tanks will eventually provide the foundation for systems going down to the ocean to explore a deeper ocean environment.'Water robots don't need oxygen. The only reason they surfaced was to communicate. ' Morgansen's robots do not need to return to the water surface until the mission is completed.

In the future, ocean robots can collaborate and monitor underwater moving targets, such as rampant whales or pollutants, exploring caves under cool icy waters. in hazardous environments. Robots of fish can work together to do things that they cannot do alone, like tracking large flocks of animals or mapping out polluted areas that can grow and change shape.

The collaborators in this work include PhD student Daniel Klein and Benjaminn Triplett, Washington University, aerodynamics and cosmology, Patrick Bettale mechanical engineering. The project receives support from the National Science Foundation and the Scientific Research Department of Air Force.

Robofish has fins designed at Washington University.The robot pre-set the coin to compare its size.(Photo: Washington University)

Robofish is about the same size as a salmon weighing about 4.5kg, looks somewhat like fish because they use fins, not propellers. Fins make them easier to control and can be reviewed lower than those with propellers.

But while other research groups are also building fish-like robots, the system is new to the point where robot fish can communicate wirelessly underwater. Once again, Morgansen took natural systems as inspiration. They partnered with Julia Parrish, a trainer in the School of Fish and Ocean Sciences, Washington University, to document the behavioral patterns of the fish.

'For herd animals, you can achieve more efficient coordination and flexible behavior than what we can do in the current engineering and engineering industry. The idea of ​​these experiments (with live fishes) is to ask 'How do they do that' and see if we can think of anything. '

The live fish training team reacted to a stimulus by swimming to the feeding area. Scientists found that even when less than one-third of the fish in the herd were trained, both the fish swam to the feeding area thanks to the signal.

'Fish with strong thoughts seem to dominate those that don't. This hides what will happen in a group of moving vehicles. Is it possible for a means of transportation to make the rest do something based on its behavior? '

In addition to finding the best way to coordinate robot movement, researchers face many other challenges in making robots transmit signals through water environments. The energy needed to send information over long distances is hampered by the fact that robots only have limited battery power. Moreover, the signal may be shortened when it bounces off the surface or obstructions.

Robots send signals to each other thanks to low-frequency ultrasonic pulses, or pressure waves. The new results show that only about half of the information is successfully received, but thanks to the way robots are programmed, they can still fulfill their tasks. Which robot can independently perform two simple instruction groups - swimming in one direction or in different directions - will be devoted to more complex tasks.

Now researchers are using the fish's coordination ability to perform a task similar to what they would face in the ocean. The first mission of this Robofish fish will be to follow a remote control toy shark.