On March 4th, 2021, Beijing time, the cover of Nature, a top international journal, published the latest research on bionic deep-sea soft robot: self-powered soft robot in the Mariana Trench, which was jointly conducted by Zhijiang Laboratory and Zhejiang University. The research team took the lead in realizing soft robot’s 10,000-meter deep-sea control and deep-sea autonomous swimming experiment!
Dr. Li Guorui, a senior researcher in the Intelligent Robot Research Center of Zhijiang Laboratory, is the first author (ranked first), Liang Yiming, an engineering specialist in the Intelligent Robot Research Center of Zhijiang Laboratory, is the second author, Professor Li Tiefeng of Zhejiang University is the correspondent author, and Professor Zhu Shiqiang and Professor Gu Jianjun, directors of Zhijiang Laboratory, are co-authors.
Unlocking the “Secret of Life” in the Deep Sea and Developing soft robot Adapting to Ten Thousand-meter Hydrostatic Pressure
Mariana Trench in the western Pacific Ocean is the deepest known ocean, with high water pressure, low temperature and complete darkness, and is called “the fourth pole of the earth”. With the continuous development of deep diving technology, it is found that the vast deep sea is not dead. There are still hundreds of species living in the ultra-high pressure deep water area between 6000 and 11000 meters in the Mariana Trench, among which snailfish is a typical representative.
Biological studies have found that the bones of lionfish are finely distributed in the gel-like soft body, which can withstand the pressure of nearly 100 MPa, equivalent to 1000 atmospheric pressures. To make an inappropriate analogy, this huge pressure is equivalent to a car weighing about a ton pressing on the fingertips. “The peculiar structure of lionfish has inspired us a lot. If we can turn the’ mystery of life’ in the deep sea into the’ power of machines’, we can develop bionic, software and miniaturized intelligent deep-sea robots that can adapt to the extreme environment of the deep sea, which can not only help deep-sea exploration, but also develop new robots and intelligent equipment. ” Li Guorui talked about the initial research and development is still difficult to suppress the excitement.
The research direction was clarified. In May 2018, the Intelligent Robot Research Center of Zhijiang Laboratory and the team of Professor Li Tiefeng from the Cross Mechanics Center of Zhejiang University launched the bionic deep-sea soft robot research based on lionfish. Based on the characteristic that the head bones of lionfish are dispersed and fused in soft tissues, the project team designed the structure and materials of electronic devices and soft matrix mechanically, and optimized the stress state in the robot body under high pressure environment. The bionic deep-sea soft robot developed by the project team looks like a fish, with a length of 22cm and a wingspan width of 28cm, which is about the length and width of an A4 paper. Hard devices such as control circuit and battery are integrated into the gel-like soft body; By designing the materials and structures of adjusting devices and software, the robot can withstand the deep-sea hydrostatic pressure of 10,000 meters without a pressure-resistant shell.
“Compared with the traditional’ armored’ anti-high-pressure deep diving equipment, we have developed a bionic deep-sea soft robot with a new technical route, striving to greatly reduce the difficulty and cost of deep-sea exploration.” Li Guorui said.
Breaking through the Limit and Innovating “Intelligent Artificial Muscle Drive”
How do deep-sea robots achieve propulsion? The robot relies on its own miniaturized energy control system and the Dielectric elastomer (DE muscle) in the oval part between the wings. When the electronic device in the silica gel body generates an electrical signal, the dielectric elastic body will generate a muscle-like deformation mode under the stimulation of the voltage signal, and the wings of the bionic robot fish will flapping with the expansion and contraction of the muscle to drive the robot forward.
However, in order to realize the driving of dielectric elastomer in deep sea, it is necessary to overcome the attenuation of electric driving performance of polymer materials under high pressure and low temperature. The project team cooperated with Professor Luo Yingwu from the School of Chemical Engineering and Bioengineering of Zhejiang University to develop an electrically driven artificial muscle that can adapt to extreme environments such as low temperature and high pressure in the deep sea, and it can still work normally even in the low temperature (0-4℃) and high pressure environment (110 MPa) in the Mariana Trench. “Another breakthrough in our research is to design an electrically driven intelligent soft material that can still maintain good electrical driving performance in high pressure and low temperature environment.” Professor Li Tiefeng said.
To sum up, the new bionic deep-sea soft robot is created by two technological breakthroughs, namely, the soft-hard fusion machine system adapted to the deep-sea hydrostatic pressure and the new dielectric elastomer actuator adapted to the deep-sea high-pressure and low-temperature environment.
Fearless abyss soft robot has broad application prospects.
In the course of research, a series of numerical calculations and a large number of pressure environment simulation experiments have verified the feasibility of the scheme. In order to further prove the reliability of the robot in the deep-sea field environment, with the joint support of Shanghai Ocean University, Institute of Deep-sea Studies of Chinese Academy of Sciences, Dalian Maritime University, Guangdong Marine Geological Survey and other units, the bionic robot developed by the project team has successively carried out deep-sea sea trials in Mariana Trench, China Nanhai and other sea areas.
In December 2019, the bionic deep-sea soft robot sat at the bottom of the Mariana Trench. The image records of the sea trial showed that the robot achieved a stable flapping-wing drive at the depth of 10,900 meters in the Mariana Trench. On the night of August 27th, 2020, the soft robot successfully swam autonomously in the depth of 3224m in the South China Sea. “At three o’clock in the morning, we watched the minutes in the master control room, waiting for the robot to start at the bottom of the sea. When the robot successfully completed the scheduled swimming, the hanging heart was finally put down, and several years of difficult exploration finally made milestone progress. ” Li Guorui said.
“Our robots have good development and application prospects in harsh and special environments such as deep sea, polar regions and high impact.” Li Guorui said. In the future, the project team will continue to study the integrated system of energy, drive and perception of deep-sea software intelligent equipment to improve the intelligence of bionic deep-sea soft robot and reduce the application cost. Liang Yiming said: “We also plan to apply the key technologies of bionic soft robot to the submersible, develop miniaturized deep-sea equipment, and realize functions such as deep-sea communication and deep-sea detection.”
(Source: Zhejiang Online)