Researchers developed robotic cockroach that are capable of exploring underwater environments, according to a study published on July 2, 2018.
This study was conducted by the researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences. Harvard’s Ambulatory Microrobot, also known as HAMR is capable of walking on land, swimming on the surface of water, and walking underwater for as long as necessary.
Multifunctional foot pads that depends on surface tension and surface tension induced buoyancy are used by HAMR when it has to swim but can also apply a voltage to break the water surface when it needs to sink. This process which reduces the contact angle between a material and the water surface under an applied voltage is called as electrowetting. The objects can easily break the water surface when there is a change of contact angle.
Neel Doshi, co-author of the paper said, “HAMR’s size is key to its performance. If it were much bigger, it would be challenging to support the robot with surface tension and if it were much smaller, the robot might not be able to generate enough force to break it.” This robotic cockroach weighs 1.65 grams and can carry 1.44 grams of additional payload without sinking in the water. Moreover, it can paddle its legs with a frequency up to 10 Hz and is coated in Parylene to keep it from shorting under water.
When it is underwater, it uses the same gait to walk as it does on dry land and is just as mobile. To return to dry land, HAMR faces enormous challenge from the water’s hold. Furthermore, researchers will work on improving the locomotion of HAMR and will find a way by which it can return to the land without a ramp. This might be possible by incorporating gecko-inspired adhesives or impulsive jumping mechanisms into the robotic cockroach.