Engineers have developed a new robot that can swim underwater, then rise to the surface and take flight, in an aerial-aquatic feat that mimics some of nature’s most formidable fliers and swimmers.
Developed by researchers at the Massachusetts Institute of Technology (MIT) and the Swiss Federal Institute of Technology Lausanne (EPFL), the new robot’s capabilities could help launch a new generation of aerial-aquatic exploration vehicles.
Dubbed the “Flapping-Wing Aerial-Aquatic Vehicle” (FAAV), this lightweight robotic platform weighs less than 300 grams and can transition seamlessly between water and air with its very flexible flapping wings. Now, the team’s findings, published in the journal Science, could help scientists better understand how diving birds, which include puffins, petrels, loons, and gulls, are so adept at navigating two vastly different environments.
Such capabilities, the team says, could also pave the way toward advanced drones in the coming years that could transform ocean research.
Inspired by Diving Birds
Departing from conventional modern designs employed for aircraft or underwater vehicles, the team based their design on diving birds, which evolved to fly over water, then plunge beneath the waves to hunt for food, before surfacing and resuming flight.
One problem when it comes to replicating these abilities in robots involves the density of water, which is around 1,000 times denser than air. Because of this, the engineering team had to carefully balance the flexibility of the robotic wings in their design, along with flapping frequency, tail angle, and other factors that allowed the robot to move efficiently through both environments without requiring propellers or separate propulsion systems.
Finding the Sweet Spot for Transmedium Travel
Experiments were undertaken by the team in the lab and in Switzerland’s Lake Geneva, and helped the team determine that the robot achieved best performance with medium-sized wings that flap at approximately five times per second. Under such conditions, the robot was able to swim one meter per second, then by pitching upward at a 70-degree angle, it could break through the surface, and continue this same movement to propel itself through the air.
Although the robot still has some limitations compared to the avian examples that inspired it, interestingly, it does appear to have one advantage: unlike diving birds, which paddle using their feet to achieve aquatic launches into the air, the new robot has no such requirement, and can transition from water to air relying only on its wings and adjustable tail.
Future Drones with “Aerial-Aquatic” Abilities
In the future, drones equipped with such capabilities could be leveraged to monitor marine ecosystems in a variety of ways. The team also says it could help to observe environmental concerns, such as water near glaciers or offshore infrastructure, or even collect data from hazardous locations that are either too difficult or simply too costly for ships to reach.
“Our dream vision is for oceanographers, marine biologists, and members of coastal communities to launch this robot from a boat, or from shore, and it would fly close to the area of interest, such as an iceberg or a port facility, or over a pod of whales,” according to Raphael Zufferey, assistant professor of mechanical engineering at MIT.
“It would dive into the water to take a measurement or collect a sample, and fly back to deliver the data at a fraction of the cost of traditional methods. Then it could go back out to dive for more,” Zufferey recently told MIT News.
Drawing from movements in nature influenced by evolution, the researchers hope their bird-inspired design may eventually help scientists by introducing cost-effective, but formidable new tools to help obtain information from some of the most challenging environments, all with help from robots that can do what only nature’s diving birds could once achieve.
The achievement is detailed in a new paper, “Leaping out of the water: aerial-aquatic locomotion with flapping wings,” which appeared in the journal Science.
Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. A longtime reporter on science, defense, and technology with a focus on space and astronomy, he can be reached at micah@thedebrief.org. Follow him on X @MicahHanks, and at micahhanks.com.