Innovative ALBATROSS Robot Spins Like a Maple Seed Then Sails Off Across the Water

Researchers at the Singapore University of Technology and Design built a small robot that leaves a drone, spins on the way down, and keeps moving once it meets the water. They named it ALBATROSS, short for Airborne Lander with Buoyant AuToROtating Sailing Sensor. Lead author Shane Kyi Hla Win, working with professor Foong Shaohui, describes the machine in Science Robotics as a way to put sensors on a lake or a sheltered stretch of sea without sending a boat out to meet them.

A drone raises the one-kilogram prototype about 150 meters and then releases it. The inflexible wingsails attached to one side of the hull grab some air and begin spinning within a few seconds, much like a maple seed does on its journey to the earth. During tests on a reservoir, the craft settled into a very constant glide of around 7.4 meters per second, or roughly 26 kilometers per hour. According to Foong’s team, an identical hull without the spin would smack into the sea with nearly 18 and a half times the force, so the wings effectively negate the need for a parachute.

The weight is responsible for landing the thing. A good heavy keel and ballast will turn the boat upright in approximately a second after it enters the water, and no power is required to flip it over. Once it floats, those same wings transform into sails. The main sail just turns freely with the help of a tail rudder, whilst a smaller front sail can alter angle to maintain the spin stable and catch any wind on the sea. To complete the task, only three actuators and three navigation sensors are required, which is quite small when compared to some air-and-water machines that require six to eight actuators.

Once it reaches that threshold, the wind takes over. Trials on Singapore’s Bedok and Pandan lakes revealed that a larger test version could reach a top speed of roughly a kilometer per hour and maintain that speed for nearly three hours while recording humidity, heat, and wind direction. Not bad given it only consumed almost half of its main battery. When the air lowers, a rudder shaped like a fish tail starts rotating and can provide the ship a moderate push forward at up to 0.4 meters per second, allowing it to make some headway when operating upwind.

Currently, the limit is relatively calm water. The design is primarily intended for still reservoirs and peaceful areas of coastline, and the team believes it would not last long in severe swell. Future versions are expected to be able to stay out for weeks, monitoring things like algal blooms, oil spills, trash, and the flow of heat between the sea and the air, and having a rapid release mechanism will come in useful if they need to conduct a search or inspect a remote beach. For now, though, it’s all about the sequence: one set of wings, one drop, one smooth landing, and a miniature boat that sails away on its own.