When we talk about drones we automatically think of flying vehicles, but there are also underwater drones. What is not so common is that the same drone is capable of doing both. It’s just what MIT has just achieved: a small robot with wings able to fly and dive into wateras if it were a seabird when it hunts.
The robot, which they have baptized with the not at all suggestive name “flipping-wing air-water vehicle” (FAAV), has been developed by a team of engineers from MIT and EPFL and lays the foundations for the creation of a new type of drones capable of moving in various environments.
Inspired by nature
The design is nothing like that of a typical flying drone since it does not have propellers, but to fly it uses two wings like those of a bird. The wings are attached to a small central fuselage where the battery and motor that move them are located.
The wings are made of a thin membrane with a water-repellent coating that repels water, so that it does not add weight or slow down your movements when leaving the water. It also has an adjustable tail that allows you to make turns and adjust the inclination both when entering and leaving the water. In total it weighs only 300 grams.
For its creation, engineers analyzed the characteristics of more than 100 species of diving birds, such as puffins, petrels and kingfishers. What they have observed is that smaller birds are capable of flapping their wings about ten times in the air and four times in the water, while the frequency is lower in the case of larger birds such as seagulls. To simulate different types of flight, they created several types of wings of different sizes that can be interchanged.
There is a curious nuance and that is that the majority of diving birds use their legs to gain momentum and take off from the water. The robot does not have them and still achieves the same effect, The trick is in the takeoff angle. After several tests they saw that it needs to leave the water at 70 degrees, if it goes too far, instead of taking off, it falls backwards.
Remote research and exploration
The logical question is what is this for, and there are two answers. The first is that they wanted to study in more depth the flight mechanics of these birds and how they modify it when going from air to water and vice versa. The second is to use this robot as exploration vehicle for remote areas.
The idea of Raphael Zufferey, lead author of the study, is that these robots can be launched from a ship or the coast to fly to areas of interest (such as an iceberg, a port, a group of whales), submerge to take a sample or measurement, and fly again to deliver the data. Everything a lot cheaper than with traditional oceanographic meansand with the possibility of repeating the process every hour instead of every week.
The team’s next steps include give the wings turning capacity (in addition to flapping) and test the robot in more adverse conditions, such as rough water or wind.
Images | M.I.T.
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