Researchers from Harvard John A. Paulson School of Engineering and Applied Sciences developed an underwater robotic cockroach capable of swimming and walking.
Cockroaches are capable of surviving underwater for around 30 minutes. Now, researchers from Harvard John A. Paulson School of Engineering and Applied Sciences created a robotic cockroach that can sustain underwater for even longer duration. The Harvard’s Ambulatory Microrobot (HAMR), can walk and swim both on land and underwater. HAMR is laced with multifunctional foot pads that apply the principle of surface tension to walk on land and surface tension induced buoyancy to swim. It ability to apply a voltage to break the water surface enables it to sink underwater. This process is called electrowetting. Moving on water surfaces allows HAMR to pass through submerged obstacles and reduces drag. The four pairs of asymmetric flaps and custom designed swimming gaits enables HAMR robo-paddles on the water surface to swim. The research was published in the journal Nature Communications on June 27, 2018.
The researchers state that the size of HAMR is the key to its performance. It weighs 1.65 grams and is capable of carrying an additional payload of 1.44 grams without sinking and can paddle its legs with a frequency up to 10 Hz. Its Parylene cover protects it from shorting underwater. HAMR uses on land- gait movement to walk once it is on underwater surfaces. The water surface tension force and induced torque elevates friction on the robot’s hind legs. To overcome such friction and hold the researchers stiffened the robot’s transmission and installed soft pads to the robot’s front legs. These soft pads increase payload capacity and redistribute friction during climbing, which in turn enables the robot to break out of the water’s hold. The researchers aim to further improve HAMR’s locomotion to avoid ramping while returning to land.