Picture provided by: Harvard Microrobotics Lab

Cockroaches can survive underwater for the duration of at least half an hour. With the advancement, a robotic cockroach is expected to survive underwater even more than it. A Harvard’s Ambulatory Micro Robot which is popularly known as HAMR can walk on land and swim in water. Also, it can walk as long as it is required underwater. 

With this next-generation advancement, HAMR has footpads which are multifunctional. These footpads rely on surface tension which creates buoyancy when it is required by a HAMR to swim. Also, it can provide a voltage break for breaking the water surface when HAMR is looking forward to sinking. The process of reducing the contact angle between surface water and material by making use of voltage is known as electro-wetting. By making these changes in corners, it is expected that it will offer flexibility to objects for breaking the water surface.

By having the capability to move over the water surface, a micro-robot can avoid obstacles which are present underwater. HAMR paddles over the water surface for swimming by making use of four pairs of flaps which are of asymmetric nature and swimming gaits which are custom designed especially for it.

“According to this research, it can be concluded that micro-robotic can be used for small-scale physics which is surface tension here to perform different functions which are a big challenge for a robot which is big in size.” Kevin Chen mentioned this. He is the first author of the paper.

In Nature Communications journal the recent research is published.

“The size of HAMR is the main reason it can perform so well,” said Neel Doshi. He is the co-author of the paper. If it has been too large or too small, then it would be challenging to support the robot with the surface tension.

The weight of HAMR is near about 1.65 grams which is equivalent to the importance of a large paper clip. Also, it can carry more weight of 1.44 grams without sinking and can paddle efficiently with this much weight. To avoid shorting it is coated with Parylene.

HAMR after reaching underwater make use of gait for walking similarly as it does on dry land. For returning to dry land HAMR has to face a lot of challenges caused by water’s hold. A surface tension force of water whose weight is almost double the weight of the robot tries to push the robot downwards.