Robot fish that swims in toxic lakes can propel itself and fly off

12 Sep 2019

Illustration of the robot leaping out of the water. Image: Aerial Robotics Lab/Imperial College London

Engineers have developed a flying robot fish designed to collect water samples, which can leap out of water and fly back to base.

Researchers from Imperial College London have ‘leapt’ to the challenge of creating a robot that could travel into hazardous waterways and fly back to base. The flying robot fish design, detailed in Science Robotics, uses water from the environments to create a gas capable of launching it from the water’s surface.

Once airborne, it can travel for up to 26 metres, by which time it would have collected water samples to determine the extent of flooding in an area or for monitoring ocean pollution. While robots similar to this have been designed in the past, they require a lot of power to launch, making many of them unfeasible.

However, this new system requires just 0.2g of calcium carbide powder held in a combustion chamber. The only moving part in the soft robot is a small pump that brings in the water for the chemical reaction to happen.

Once combined, the water and calcium carbide creature a burnable acetylene gas. As it expands and ignites, it pushes the water out as a jet, propelling the machine out of the water.

“Water-to-air transition is a power-intensive process, which is difficult to achieve on a small-scale flying vehicle that needs to be lightweight for flight,” said lead researcher Dr Mirko Kovac.

To test it, the researchers put the flying robot fish in three different arenas: a lab, a lake and a wave tank. In all three, it was able to escape the water’s surface even in rough conditions, unlike others that have required much calmer water.

The robot is lightweight at 160g and has the capacity to jump multiple times after refilling its water tank. This, the researchers said, could allow it to take water samples at multiple points without needing additional power compared with an electric robot.

First author of the paper, Raphael Zufferey, said: “These kinds of low-power, tether-free robots could be really useful in environments that are normally time- and resource-intensive to monitor, including after disasters such as floods or nuclear accidents.”

Colm Gorey was a senior journalist with Silicon Republic