Image credit: Rafael Zoveri
Nature has given us amphibians in various forms, from frogs to other multi-habitat creatures, yet few things transcend Earth’s different domains as markedly as the diving birds that have inspired researchers at MIT and École Polytechnique de Lausanne. Scientists have long dreamed of a machine that could fly through clouds like a bird, swim into the depths of the ocean, and then seamlessly return to the sky.
Diving birds, such as the Atlantic puffin, glide easily between air and ocean, although the physical characteristics of the two environments are different. Now a team of engineers from MIT and the Swiss Federal Institute of Technology (EPFL) has finally created a lightweight winged robot that possesses this biological ability, demonstrating that the same wings can navigate through both worlds. This achievement is a huge step in how we explore and monitor our vast and mysterious oceans.
What makes this robot from MIT so special?
To understand the significance of this achievement, we have to look at the science first. Water is about 1,000 times denser than air. A wing designed to lift a robot into the air is usually too fragile or ineffective to survive the extreme resistance of water. Most previous attempts to create “amphibious” drones involved two different systems of propellers and wings working together, making them heavy and complex.
The MIT-led team, headed by Rafael Zoveri, took a different approach by looking at puffins. Their creation, known as the Flapping Wing Aerial Vehicle (FAAV), weighs less than 300 grams, roughly the weight of a large apple. It does not use additional fans or motors. Instead, it relies entirely on a single pair of wings to fly and swim. By studying nearly 100 species of diving birds, researchers have built a machine that handles the transition between air and water seamlessly.
How does this amphibious robot handle air and water at the same time?
The secret lies in the flexibility of the wing. Instead of using mechanical joints to fold its wings underwater like a real bird, the robot uses “flexible membrane wings” reinforced with carbon fiber struts. When the robot is in the air, these wings are stable enough to lift the robot into flight. However, the moment they hit the water, the wings passively bend by up to 90 degrees. This quick shift reduces the wing’s surface area, reducing the load on the engine, allowing it to move through the water without breaking.Another clever design choice was the “open body frame”. Instead of trying to build a heavy, airtight enclosure to protect the electronics, engineers allowed water to flood the entire system. Each individual component such as the motor, battery and sensors is separately waterproofed with silicone. This allows the robot to stay exactly where it is in the water without sinking or floating to the surface. This saves a huge amount of battery power required beforehand to avoid floating.
Image credit: John Frieda
Can this robot really take off without any running?
One of the most impressive parts of the MIT study was the “water outlet.” If you’ve ever watched a duck or puffin take off from a lake, you’ve seen them furiously paddling their feet to gain enough speed to take off. The researchers initially thought their robot would need something similar.However, they discovered a mechanical shortcut. By programming the robot to move upward at a steep 70-degree angle, the wings alone can generate enough thrust to pull it from the water into the air in less than a second.
To achieve this, the robot must flap about 10 times per second to release itself from the surface tension of the water. It’s an energy-intensive movement, but it eliminates the need for heavy robotic legs, making the machine lightweight.
What did this robot teach us about our nature?
This project is a tool for biological discovery. Scientists have long debated why diving birds reduce their wing area underwater. Is it to save energy or increase speed? By testing different wing sizes and elasticities on the robot, the team found that smaller wings did not actually save energy.
Instead, they greatly increase speed and underwater navigation. This suggests that when a puffin folds its wings, it is not trying to be efficient, but rather trying to be fast.
The robot also confirmed that larger diving birds likely use their feet to take off because launching with only the wing requires energy. Only the smallest and lightest birds, such as kingfishers, can afford to take off by foot, which matches exactly what the researchers observed in their bird-scale robot.
What does this mean for the future of ocean research?
The potential applications of FAAV are broad. Traditional ocean research often requires large, expensive vessels or slow-moving underwater robots. Zufferey’s vision is to provide a much cheaper and faster alternative. Imagine a group of these “air-aqua robots” that can fly at speeds of six meters per second, to a specific area of interest, such as a remote coral reef, or a pod of whales. They can dive in and take water samples or temperature readings, then return to base to deliver the data.
On a single charge, the current prototype can fly about four miles or swim just over a mile. Best of all, the researchers have made their designs open source.
Using approximately £230 ($300) of materials and a 3D printer, coastal communities and marine biologists can build their own fleet of aquatic aerial robots.By imitating the amazing diving abilities of birds, we are finally creating technology that can navigate our planet as seamlessly as the animals themselves, opening a new era of oceanography that is faster, cheaper and more detailed than ever before.
