An international team of scientists has created an insect-size robot capable of swimming about underwater and flying in the air.
In a paper published in the journal Science Robotics, engineer Yufeng Chen from Harvard University, US, and colleagues, describe a 175-milligram microbot “capable of flying, swimming, and transitioning between air and water”.
Proof-of-concept prototypes, as shown in this video, represent an important advance in robotics, because the tiny machines have been successfully designed to operate in two very different sets of physical constraints.
The bots feature sets of wings capable of flapping in different configurations, allowing them to navigate through air and the much denser medium of water.
For such tiny machines, the relative strength needed to not only move through water but to then break through the meniscus and suddenly recalibrate to lift into the air is considerable.
Chen and his team solved these issues elegantly. The bot contains lightweight electrolytic plates. In order to rise up while submerged, these plates interact with the water to produce oxyhydrogen, which is stored in onboard buoyancy tanks.
As the amount of oxyhydrogen increases so too does the buoyancy force. Eventually that force becomes great enough to push the robot’s wings out of the water into the air.
At this point the bot exploits surface tension to remain upright. At the same time, it produces a tiny spark which ignites the stored gas, causing the robot to take off from the water’s surface, allowing its wings to switch to aerial mode.
The next step for Chen’s team is to install tiny sensors and motion-tracking systems, allowing future swimming and flying insect-bots to monitor their own movements.