A bio-inspired robot uses water from the environment to produce a gas and then launch itself from the surface.
The robot has the ability to travel 26 m through the air following take-off and hence could be employed to collect water samples in cluttered and risky environments, for instance, while monitoring ocean pollution and at the time of flooding.
In these conditions, robots with the potential to travel from water to air are desirable. However, the launch necessitates a lot of power, which has been challenging to realize in small robots.
Currently, scientists from Imperial College London have developed a new system that needs just 0.2 g of calcium carbide powder stored within a combustion chamber. The system’s only moving part—a small pump—brings in water from the environment in which the robot is placed, such as an ocean or a lake.
Then, the calcium carbide powder and water combine in a reaction chamber, synthesizing acetylene gas that is combustible. When the gas is ignited and expands, it pushes the water out in the form of a jet, thus propelling the robot clear of the water and into a glide of up to 26 m.
The robot has been described in Science Robotics on September 11th, 2019.
Only One Moving Part
According to Dr Mirko Kovac, lead researcher and Director of the Aerial Robotics Laboratory at Imperial, “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.”
We have used water-reactive chemicals to reduce the materials that the robot needs to carry. Since the chamber fills passively and the environmental water acts as a piston, we can create a full combustion cycle with only one moving part, which is the pump that mixes the water with the fuel.
Dr Mirko Kovac, Director, Aerial Robotics Laboratory, Imperial College London
The robot was tested by the team in a laboratory, in a wave tank, and in a lake, demonstrating that it has the ability to escape from the surface of water even under comparatively harsh conditions. Similar robots usually necessitate calm conditions to glide from the water, whereas the system developed by team produces a force 25 times the weight of the robot, increasing the chances of overcoming the waves.
Next: Field Trials
The robot weighs just 160 g and can “jump” a number of times once its water tank is refilled. This could enable it to float on water and collect samples at several points without the need for extra power, thereby saving energy over longer distances than an electrically powered robot.
The researchers are now partnering with collaborators in Switzerland to develop new vehicles with sophisticated materials and start field trials of the robot in different environments, such as, monitoring offshore energy platforms and the oceans around coral reefs.
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.
Raphael Zufferey, Study First Author, Imperial College London
The investigations were performed in the Brahmal Vasudevan Multi-Terrain Robotics Arena, which was established with a philanthropic gift from Mr Brahmal Vasudevan.
Video of the robot in action and how it works. (Video credit: Aerial Robotics Lab/Imperial College London)