Our reporter Guo Guozhong and Wang Zhuhua
At present, my country has three deep-sea manned submersibles, "Jiaolong", "Deep Sea Warrior", and "Struggle", as well as "Sea Fight", "Qianlong", "Swallow", "Sea Wing" and "Sea Dragon". The series of unmanned submersibles such as No. 1 has initially established an all-sea deep submersible pedigree, and has continuously achieved new breakthroughs and major new leaps in the development of deep-sea equipment technology.
At 8:12 am on November 10, 2020, the Chinese manned submersible "Struggle" successfully dived over 10,000 meters in the Mariana Trench in the Western Pacific, reaching 10,909 meters, setting a new record for China's manned deep diving. New records and brought back precious samples of rocks, seawater, and organisms at the bottom of the trench.
Mariana Trench Challenger Abyss is called the "fourth pole of the earth", and it is also one of the harshest areas on the earth, with high water pressure, low temperature, no sunlight, frequent earthquakes...
In the words of Hu Zhen, deputy chief designer of the Struggle, “We are challenging the deepest part of the world. Especially the narrow spherical manned cabin can carry three people down to a depth of 10,000 meters, which is common internationally. Very amazing"!
A reporter from Science and Technology Daily learned that at present, my country has three deep-sea manned submersibles, the "Jiaolong", the "Deep Sea Warrior", and the "Struggle", as well as the "Sea Fight", "Qianlong", "Haiyan" and "Sea Fighter". The series of unmanned submersibles such as "Ying" and "Hailong" have initially established a full-sea deep submersible pedigree, and have continuously achieved new breakthroughs and major new leaps in the development of deep-sea equipment technology.
The successful development of the "Struggle" signifies that my country has reached the world's leading level in the field of deep manned deep diving, and has also given mankind a powerful new platform for exploring the 10,000-meter abyss.
The development of my country's manned submersibles comes from behind
"In the past 20 years, my country's manned deep diving business has developed rapidly. In 2012, the self-integrated "Jiaolong" dived 7062 meters, which is the first step for the Chinese to take an operational manned deep diving journey." China State Shipbuilding Corporation Ye Cong, deputy director of the 702 Research Institute and chief designer of the Struggle, said that from 2017 to the present, the “Deep Sea Warrior”, which has realized localization of all key components, has carried out more than 300 dives. The domestically-made components have withstood the test.
It should be said that my country started relatively late in the research of deep-sea manned submersibles, but it has developed rapidly.
In 1986, China's first manned submersible, the 7103 lifeboat, was successfully developed.
At that time, although it could only dive 300 meters, it was a more advanced rescue manned submersible in that era.
In the new century, with the support of the 863 program, the research and development of independent deep-sea manned submersibles began.
Especially in the 4 years of sea trials, the "Jiaolong" scientific research team has continuously improved and improved the submersible, solved the problems encountered in the sea trial and the shortcomings discovered, so that the "Jiaolong" not only has the world's advanced hovering And the automatic driving function, it can also carry out digital underwater acoustic communication and positioning, and it can more steadily "fix" on the seabed to carry out complex operations tasks.
Over the years, scientific researchers have actively practiced the deep-sea strategy and unswervingly promoted the pedigree of manned submersibles.
In the view of Xiang Changsheng, deputy director of the Deep Sea Technology Laboratory of Hainan Province and director of the Science and Technology Department of the Institute of Deep Seas of the Chinese Academy of Sciences, unlike the "Jiaolong" project established and developed in 10 years, my country's second-generation 4,500-meter manned submersible——" The "Deep Sea Warrior" took only 8 years from the development of the project to the sea trial delivery, and the localization rate reached 95%, making it more practical.
As of June 7, 2021, "Deep Sea Warrior" has completed nearly 400 dive missions. The frequency, cost, and ability of operations are all at the world's advanced level, with outstanding results.
It is worth mentioning that as early as 2016, when the "Deep Sea Warrior" was not launched, the 10,000-meter-class manned submersible began to be developed simultaneously, that is, the "Struggle" all-sea deep manned submersible.
This is the core task of the key special item of the "Thirteenth Five-Year" national key research and development plan "Key Deep-sea Technology and Equipment".
my country has already had 10,000-meter-class unmanned submersibles before, so why develop 10,000-meter-class manned submersibles?
"The project mainly uses the technical foundation of the'Jiaolong' deep-sea submersible and deep-sea exploration equipment to advance to the deepest part of the world’s oceans. The purpose is to conduct scientific investigations and experiments in the Mariana Trench, establish and develop my country’s marine fighting abyssal biology, Sea fighting abyss ecology, sea fighting abyss geology and other discipline systems, and using this as a guide, further conquer the key technology of deep sea exploration equipment, and promote the leap-forward development of deep sea science and deep sea equipment technology in China." Ye Cong said.
Assemble nearly a thousand scientific researchers to overcome difficulties
"In the development of the'Striver' all-sea deep manned submersible, we have assembled 20 research institutes, 13 universities, 60 research institutes, including the 702 Research Institute of China State Shipbuilding Corporation, the Institute of Deep Sea Science and Engineering of the Chinese Academy of Sciences, etc. Nearly a thousand scientific research personnel including Yu Jia Enterprise have organized and carried out key technical research on the basis of the development and application of the "Jiaolong" and "Deep Sea Warrior" manned submersibles." Ye Cong said.
The reporter learned that the project was formally established in 2016. The Ministry of Science and Technology has set up 19 projects and invested 767 million yuan in central government funding around the overall goal of research on deep-sea manned submersibles.
Among them, the 702nd Research Institute of China Shipbuilding Corporation took the lead in the overall design and integrated construction of the Struggle, and the Institute of Deep Sea Science and Engineering of the Chinese Academy of Sciences took the lead in conducting sea trials as the owner.
The joint R&D team has gone through nearly 5 years in design and safety evaluation of pressure-resistant structure, preparation and welding of titanium alloy materials, development and processing of buoyancy materials, acoustic communication positioning, intelligent control technology, lithium ion batteries, sea water pumps, operation manipulators, etc. A number of major technological breakthroughs have been achieved.
Relevant experts revealed that the Struggle combines the "excellent pedigree" of the previous two generations of deep diving equipment. It not only uses a safe, stable and powerful energy system, but also has a more advanced control system and positioning system, as well as more pressure resistance. The manned ball cabin and buoyancy materials.
"With the Chinese manned deep diving spirit of'rigorous truth-seeking, unity and cooperation, hard work and dedication, and bravely climbing peaks', we have successfully completed the design of the submersible, the assembly and construction of the submersible, the joint on-land adjustment, and the tank test through the interdisciplinary integration Hehai’s test acceptance has the capability of full-sea deep entry, detection and operation, and it has officially entered the experimental application stage.” Ye Cong said.
To challenge the deepest part of the world’s oceans, the first difficulty to overcome is the huge water pressure.
The Mariana Trench is one of the harshest areas on the planet.
At a depth of 10,000 meters in the trench, the water pressure exceeds 1,100 atmospheres, which is equivalent to 2,000 African elephants stepping on a person's back.
How to make the Struggle freely walk on the seabed of 10,000 meters without fear of high-pressure extreme environments?
According to Yang Rui, a researcher at the Institute of Metal Research of the Chinese Academy of Sciences and the person in charge of the manned cabin project of the All-Sea Deep Manned Submersible, the manned cabin is the largest pressure vessel in the entire submersible. The material is very special and its success is directly related to its success. The success or failure of the entire submersible.
Therefore, the manned cabin is the core and key component of the full-sea deep manned submersible, the hardware guarantee and safety barrier for humans to enter the 10,000-meter deep sea, and it also marks the technical level of a country's manned submersible.
At that time, under extreme pressure conditions at a depth of 10,000 meters, in accordance with the target size and thickness requirements of the Struggle, the materials used in the previous submersibles could not meet the standards. It was necessary to find a high-strength, high-toughness, and weldable Titanium alloy.
However, there is no manufacturing precedent in the world, and no foreign manufacturer can be found. The only way out is to make it ourselves.
To this end, the Institute of Metal Research of the Chinese Academy of Sciences has organized a number of companies and research institutes within the United Nations to form a "national team" for the development of the deep-titanium alloy manned cabin. After a series of investigations, demonstrations, and research experiments, the materials and molding of the manned cabin A series of key technical bottlenecks such as welding and welding.
"Our original new titanium alloy material has successfully solved the strength, toughness and weldability problems faced by the manned cabin materials, and finally manufactured a spacious and strong manned cabin made of new titanium alloy materials." Yang Rui said. .
The reporter learned that the manned cabin of the Struggle is spherical, capable of accommodating three submariners at the same time.
Previously, some foreign deep-submersible vehicles successfully challenged the pressure of 10,000 meters by relying on the spherical manned cabin, but the cabin space can only accommodate 1-2 people and cannot carry more people and equipment.
The deep sea is pitch black and the terrain environment is highly complicated. How can the Struggle avoid the risk of "strike on the rocks"?
Researchers from the Shenyang Institute of Automation, Chinese Academy of Sciences, tackled technical problems such as large-inertia carrier multi-degree-of-freedom navigation and control, safe and reliable operation of the system in the abyss and complex environment, and made the "Struggle" control system based on data and Online intelligent fault diagnosis based on model prediction, fault-tolerant control based on online control distribution, and autonomous collision avoidance on the seabed.
"The neural network optimization algorithm we designed allows the Struggle to cruise, navigate and hover over the complex terrain of the seabed." said Zhao Yang, a researcher at the Shenyang Institute of Automation, Chinese Academy of Sciences and deputy chief designer of the Struggle. .
In addition, the scientific researchers also installed a pair of highly flexible and powerful "hands" for the "Struggle". When carrying out 10,000-meter operations, they have strong operational capabilities and successfully complete rocks, biological grasping and sediments. Precise tasks such as sampler operation.
This technology fills the gap in my country's application of full-sea deep hydraulic manipulators for 10,000-meter operations.
In February 2020, the "Struggle" completed the final assembly and on-land joint adjustment as planned, and the tank test was immediately carried out in March.
In the course of the tank test, a total of 25 test tasks including full-process assessment and multiple submariners undertaking training for diving in the tank were completed.
To swim in the deepest part of the world's oceans in the future
Ye Cong told reporters that from July to November 2020, the "Striver" officially entered the sea trials. A total of 30 submarine tests were carried out, and the total subsea operation time was 141 hours.
Among them, 8 dives in the Mariana Trench exceeded 10,000 meters, the longest time in the water was 13 hours, and the maximum dive depth was 10,909 meters.
The reporter learned that the continuous and repeated 10,000-meter-level sea trials of the Struggle not only verified that the overall performance of the submersible is stable and the system is reliable, and that it can meet the safety regulations of large-depth manned submersibles; at the same time, it has passed Use the manned cabin, buoyancy materials, lithium batteries, thrusters, sea water pumps, manipulators, acoustic communication, hydraulic pumps, underwater positioning, navigation control, imaging sonar and other key equipment and important technologies produced in China. They are also domestic watertight connectors. It provides a test opportunity at a depth of 10,000 meters, fully verifies the full-sea deep operation capability and practical value of the manned submersible, and lays the foundation for subsequent operation and maintenance applications.
Relevant experts believe that the successful development and sea trial of the Struggle has significantly improved my country’s manned deep diving technical equipment capabilities and independent innovation level, and promoted the development of submersibles to the deep-sea pedigree and functionalization. Deep-sea scientific mystery, protection and rational use of marine resources have provided another weapon, and made outstanding contributions to guiding the public’s awareness of the ocean, raising the nation’s awareness of the ocean, and accelerating the building of a maritime power.
On March 16 this year, the "Struggle" all-sea deep manned submersible delivery event was held in Sanya.
On the same day, the team of experts participating in the acceptance agreed that the Struggle had many significant advantages in the 10,000-meter sea trial, such as the cabin that can carry 3 people, the ability to operate continuously for 6 hours on the seabed, and the sea trial process. It has reached the seabed of 10,000 meters deep in 8 times, the operational capabilities demonstrated in the collection of various types of scientific research samples and multiple target search, deployment and recovery operations, automatic cruise, and high-speed digital underwater acoustic communication linked to the surface of the water. The "Struggle" has comprehensive technical strength in the 10,000-meter class.
The on-site acceptance score of the "Struggle" sea trial reached 99.25 points.
Sun Qing, member of the Scientific Steering Committee for the User of "Deep Sea Warrior" and "Fighter" manned submersibles, and former director of the Ocean Division of China Agenda 21 Management Center, is the "Jiaolong", "Deep Sea Warrior" and "Fighter" Participants and witnesses who were delivered three times.
He said: "The full-sea deep manned submersible'Struggle' was officially delivered to the owner. This is the first step and an important step for my country to reach the peak of deep-sea scientific research. However, there is still a lot of scientific investigation work ahead. To do, many new problems have to be overcome."
Professor Jian Zhitian of Tongji University revealed that in the future, the Manned Submersible User Scientific Steering Committee will build a communication and exchange platform for the scientific application of the "Deep Sea Warrior" and "Struggle" manned submersibles, and actively promote the development of manned submersibles. Deep dive international cooperation to promote the multidisciplinary integration and application of academic communities.
In Ye Cong's view, in the near future, my country's self-developed 10,000-meter manned submersible will carry more Chinese scientists freely to swim in the deepest part of the world's oceans and realize their scientific dreams.