Prototype robot drops from a plane, lands, and sails on wind

A robot falls out of the sky over empty water, spinning slowly like a maple seed, and then it is sailing. That is the sequence the team at the Singapore University of Technology and Design (SUTD) has shown with ALBATROSS, a prototype designed to be dropped from an aircraft over remote waters and then to stay at sea on its own.

The problem it targets is a trade-off. Boats can stay in an area for long periods, but they can take a long time to get there. Aircraft reach a destination quickly, but cannot stay on station nearly as long. ALBATROSS, short for Airborne Lander with Buoyant AuToROtating Sailing Sensor, is meant to use both strengths. Its two rigid wingsails slow the fall through autorotation, the passive spin that the team compares to a maple seed. That means no separate parachute or landing mechanism. Once on the water, the platform rights itself through its weight distribution, and the wings act as sails. A fish-tail-inspired rudder steers it, and it moves between set waypoints using just three actuators and three navigation sensors.

In the tests reported so far, a prototype released from 150 meters (492 ft) stabilized during descent and landed with low impact. The researchers estimate that a similar platform without the autorotation system would take about 18.5 times more impact energy when it hits the water. A larger prototype, tested on a reservoir in Singapore, reached a peak sailing speed of about 1 km/h (0.62 mph) and ran for about three hours, gathering humidity, heat and wind direction data with its onboard sensors.

For the people who monitor remote seas, the change would be in how quickly and how long a sensor can be put to work. If the design holds up, a platform that lands itself and runs on wind could be placed over an area far from any port, then left to collect data for weeks rather than hours. The researchers name environmental monitoring, climate change research, search and rescue and maritime security as possible uses. The timing is the open question. The team's own description is blunt: ALBATROSS has so far worked only in sheltered test waters, and getting it ready for open-sea conditions is the next stage. That means a more rugged, durable design, and later versions with underwater sensors, sonar and larger energy storage.

The study was published in Science Robotics, with Dr. Shane Kyi Hla Win as lead author. Prof. Foong Shaohui, of SUTD's Engineering Product Development Pillar, put the logic simply: the design uses the environment rather than fighting it.