A bionic robot from China has proven in a test in the Marianne graben that it can withstand the immense water pressure. The design opens up new possibilities for deep-sea research.
Only about five percent of about 300 million square kilometers of seabed have been explored so far. Thanks to the development of a new deep-sea robot in China, however, this could soon change.
A research team led by scientist Tiefeng Li has designed a robotic ray at Zhejiang University in China. The fish-like research device was presented together with all test reports in the science magazine Nature. There, the team also published videos showing the robot rays in action.
Due to the extremely high pressure in the deep sea, rigid housings and pressure compensation systems are typically required to protect mechatronic systems. However, deep-sea creatures lacking bulky or severely pressure-tolerant systems can thrive at extreme depths.
Design of the robot ray copied from real deep-sea fish
The structure of the robot ray is inspired by a deep-sea snail fish, the article continues. Strictly speaking, this is the deep-sea disc belly.
The advantage of this fish is that its body is softer than that of other fish. Therefore, it can withstand the great pressure in the depth better than other conspecifics.
Following this model, the Chinese scientists also developed the ray. With 22 centimeters Its length is almost as long as its role model. To imitate the soft body, the robot is made of elastic silicone rubber.
Robot ray is powered by battery
It is powered by artificial muscles made of an electroactive plastic. These are contracted by current pulses from an integrated lithium-ion battery and then relax again.
This sequence of movements can be compared to wing beats. This enables the ray to move at a speed of five centimeters per second.
During the development of the deep-sea robots, it was also important to protect the sensitive technology from the immense water pressure. To ensure this, the equipment was distributed decentrally over the entire body of the ray.
A pressure-resistant electronic circuit specially developed for the robot can also measure changes in water pressure.
Robot rays swim for almost an hour in the Mariannengraben
The functionality of the robot ray was tested in three steps. First, the researchers tested their newly developed ray in a high-pressure water tank in the laboratory.
After passing the test, they exposed an identical robot in the China Sea at a depth of 3,224 meters.
After that, the research ray finally dived into the Mariannengraben. There it withstood a depth of 10,900 meters and a water pressure of 100 megapascals. This is almost 1000 times the air pressure at sea level.
According to media reports, the ray swam for about 45 minutes before rising again of its own accord.
Researchers hope for robot swarm
In the future, the researchers want to send not just one, but several robots into the deep sea. Speaking to the online magazine Sixthone, one of the co-authors of the Nature article Zhou Haofei said that the lower cost could make it possible to design entire swarms of robots in the future.
“The ocean is huge, it’s impossible to rely on a single robot being able to study everything,” Zhou said. In his view, there is much to improve. A communication system, for example, would allow the robot to transmit the collected data directly.
Despite the need for improvement, one thing is clear: the new approach to the design of the robotic ray opens up new possibilities for deep-sea research. This could soon increase the five percent of our knowledge about the seabed.
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