China's deep-sea robot conquers world's deepest trenches

A Chinese team has developed a small robot that can operate in the world's deepest sea trench under extremely high pressure.

The robot's operational ability is an engineering marvel that was previously achievable only by large, rigid submersibles weighing several tonnes.

Drawing inspiration from the movement patterns of the batfish, researchers led by Beihang University faculty members designed a 50-centimeter-long robot capable of swimming, gliding and crawling.

Experts report that this pressure-resistant robot has successfully completed these tasks in the Haima Cold Seep and the Mariana Trench at depths of 1,384 meters and 10,666 meters, respectively. "We've figured out how to make its movement in the deep sea just as good as, or even better than it performs on land under normal temperature and pressure," said Wen Li, a professor from the Department of Mechanical Engineering and Automation at Beihang University.

While swimming, the robot generates thrust through its tail fin, reaching a maximum speed of 5.5 centimeters per second. When crawling, it can move at 3 centimeters per second on sandy surfaces using its limbs, according to the study published this week in the Science Robotics journal. 

In the 10,600-meter-deep Mariana Trench, pressure can reach 110 million pascals – akin to a 1-tonne weight being placed on a thumbnail. The team crafted a flexible actuation device that exploits the stiffening properties of soft silicone materials under high pressure.

"The material structure transforms external high pressure into enhanced speed and amplitude for the actuator, turning the weakness into an asset," said Pan Fei, the paper's first author from Beihang. 

In deep-sea temperatures of 2 to 4 degrees Celsius, the team attached shape-memory alloy springs to the robot's actuator. By heating the springs with periodic currents to force them to alternately contract, they enabled high-frequency, rapid oscillation, according to the study.

Currently, the team is actively pursuing research in the field of deep-sea morphable robotics combined with artificial intelligence, aiming to create more extensive opportunities for intelligent operations in deep-sea environments.

(With input from Xinhua)