Tiny amphibious robot could aid in search and rescue missions

A tiny amphibious robot could help in search-and-rescue missions and monitoring water quality, its creators have said.

The international team of researchers were inspired by insect life as they designed the flapping 175mg drone. The robot can navigate between the air and water repeatedly, giving it the adaptability needed for a variety of tasks.

Among the requirements for air-to-water and water-to-air transitions, breaking the water is one of the most challenging, especially for tiny robots. The team, including researchers at Harvard University, successfully broke through that barrier by using an innovative technique.  

The flapping robot descends to the water’s surface. Breaking the surface tension with its titanium legs, the drone immerses itself and sinks. It then gradually "swims" to the surface, where it breaks surrounding water down into hydrogen and oxygen, storing them in a gas container. It then ignites the gas with a spark, throwing itself into the air and staying aloft.

“This is the first microrobot capable of repeatedly moving in and through complex environments,” said first author Yufeng Chen. “We designed new mechanisms that allow the vehicle to directly transition from water to air, something that is beyond what nature can achieve in the insect world.”

At the millimetre scale, the gas propellant is needed because the water’s surface tension is 10 times the weight of the tiny robot and three times its maximum lift. The device “represents a platform where forces are different than what we - at human scale - are used to experiencing,” said senior author Robert Wood. “While flying the robot ‘feels’ as if it is treading water; while swimming it ‘feels’ like it is surrounded by molasses... these small robots give us the opportunity to explore these non-intuitive phenomena in a very rich way.”

The team, also involving researchers from London, California and Hong Kong, are working on enhancing motion-tracking systems and adding sensors to monitor the environment. Their paper was published in Science Robotics.

Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.