Drawing provided by Shenyang Automation Station for "Qianlong No.3"

Have you ever seen the "Clownfish" that is bigger than people? There is such a "Clownfish" in the Shenyang Institute of Automation of the Chinese Academy of Sciences (hereinafter referred to as the Shenyang Institute of Automation), which is 3.5 meters long, 1.5 meters high and weighs 1.5 tons. Its full name is "Qianlong No.3" 4500 meter autonomous underwater robot, which was once famous for the appearance of "Clownfish" Nemo.

It is reported that there are four members of the "Qianlong" series of autonomous underwater robots, who have successively carried out ocean voyages in the Pacific, Atlantic, Indian Ocean and other waters, making important contributions to China's independent exploration of deep-sea resource mining areas. Among them, "Qianlong 2" has made a total of 59 dives, ranking first among family members.

Liu Jian, the chief designer of "Qianlong 2" and "Qianlong 3" and a researcher at Shenyang Institute of Automation, introduced to China Science Daily: "The 'Qianlong' series was born during the 12th and 13th Five Year Plans. However, our team has been exploring and researching in the field of autonomous underwater robots for decades, and Zui has finally completed the development of domestic deep-sea autonomous underwater robots from scratch, from catching up to running in parallel

Recently, the "Qianlong" series deep-sea autonomous underwater robot research and development and application team won the 2021 Science and Technology Promotion Development Award of the Chinese Academy of Sciences.

Core technology cannot be purchased with money

The deep sea contains treasures that are far from being recognized and developed on Earth, and is an important strategic Xinjiang region for human survival and development in the future. Deep sea mineral resources are considered an important terrestrial mineral replacement resource in the 21st century, and as an undeveloped treasure land and one of the high-tech application fields, they have become an important strategic goal for various countries.

Since 2001, China has successively obtained five ocean bottom exploration contract areas, including three resource types: polymetallic nodules, polymetallic sulfides, and cobalt rich crusts, effectively expanding new sources of national strategic resources. With the signing of exploration contracts for these mining areas, the demand for high-precision and deep-sea exploration equipment has also emerged. Autonomous underwater vehicle (AUV), as a kind of unmanned cableless Submersible that can detect underwater for a long time, is a means for people to understand, develop, utilize and protect the ocean.

It is understood that deep-sea autonomous underwater robots can conduct large-scale, full coverage, and high-precision detection of seabed topography, geological structure, seabed flow field, marine environmental parameters, and other factors by carrying multiple types of detection loads. However, there are not many deep-sea autonomous underwater robots in the world with this ability.

In the early days of our country, we rented a foreign deep-sea autonomous underwater robot, which was not only expensive but also operated by foreign personnel throughout the entire process. "Liu Jian said," China also tried to import equipment from abroad, but when it was implemented, it was indefinitely postponed. In recent years, foreign restrictions on us have become stricter

Since the core technology cannot be purchased with money, we will do it ourselves, "Liu Jian recalled. With the support of national and ministerial projects, Shenyang Automation Institute, in conjunction with domestic advantageous units, began developing the" Qianlong "series of deep-sea autonomous underwater robots.

From principle prototype to practical model

As early as 2000, Liu Jian led a team to develop the "Qianlong" series of underwater robots, and he was the project leader of the "Qianlong 1" project. After the lake trial of "Qianlong 1", the development of "Qianlong 2" was put on the agenda.

Xu Huixi, a member of the "Qianlong" project team and a researcher at Shenyang Institute of Automation, took over the important role of the chief designer of "Qianlong No.1". Prior to this, we developed a majority of shallow water autonomous underwater robots. After participating in the 'Qianlong' project, we found that the technical requirements varied from shallow to deep water, and further exploration was needed to enhance the practicality of the equipment. "Xu Huixi told China Science Daily.

Since the project was approved at the end of 2011, the "Qianlong 1" has undergone laboratory testing, lake testing, sea testing, and voyage applications after completing its design and commissioning. Xu Huixi witnessed the growth of "Qianlong No.1" throughout the entire process, and repeated experiments have also made Xu Huixi confident.

From October 1 to 12, 2013, the "Qianlong 1" made seven dives in the Pacific Ocean and operated for nearly 30 hours near the seabed in the detailed exploration area of over 5000 metal nodules, completing the acoustic microtopography survey line task.

The development of Qianlong 2 is also underway. Unlike the cylindrical shape of Qianlong 1, Qianlong 2 resembles a standing flat fish in appearance. In appearance, "Qianlong 2" and "Qianlong 3" are a pair of "twin brothers".

This design is not simply for the sake of aesthetics. The non rotating body vertical flat fish shaped design is based on the results of hydrodynamic optimization calculations, which is beneficial for it to climb in the vertical plane of complex seabed terrain and have the ability to navigate on the water surface. Liu Jian introduced, "Although the water depth level of the 'Qianlong 2' and 'Qianlong 3' designs is only 4500 meters, they face more complex seabed terrain, and the entire seabed operation is almost completed in climbing and descending mountains

In 2019, the successful application of "Qianlong 3" in the Atlantic marked the beginning of practicality and normalization of China's deep-sea exploration underwater robots.

Domestic sharp tools for deep-sea resource exploration

The "Qianlong" series of deep-sea autonomous underwater robots are a deep-sea resource exploration system with functions such as micro terrain and geomorphology measurement, seabed photography, water anomaly detection, and magnetic detection. They not only fill the gap in China's deep-sea resource exploration, but also surpass foreign deep-sea autonomous underwater robots in some performance indicators, becoming a sharp tool for China's independent exploration of deep-sea resources.

Taking "Qianlong 3" as an example, researchers have abandoned traditional ranging sonar. "Due to the small perspective of the underwater stone forest, ranging sonar is difficult to accurately determine the surrounding environment. Introduction by Liu Jian.

During the actual seabed operation, Qianlong 3 senses the obstacles in front with the forward-looking sonar, calculates its position in combination with the inertial navigation system, navigates according to the specified navigation path based on the altitude information perceived by the Acronyms and abbreviations in avionics and the depth information perceived by the depth meter, and at the same time correctly turns on or off all detection equipment to "climb mountains and mountains" in a dark deep sea. During the voyage of "Qianlong 3", information such as its position and working status can also be sent to the mother ship through the acoustic communication system on its back.

Polymetallic sulfide resources are products of seafloor hydrothermal activity, and the seafloor hydrothermal zone includes active and inactive hydrothermal zones. The Qianlong III has a magnetometer installed at the fish's tail, which is particularly important for the exploration of polymetallic sulfide resources. Liu Jian said: "In view of the characteristics that hydrothermal precipitation will cause changes in the seabed Magnetic anomaly, the three component magnetometer can help find active and inactive hydrothermal areas and become an important equipment for exploration of polymetallic sulfide resources."

Although the "Hidden Dragon" series has successfully completed tasks every time, the placement and recycling have always been a source of concern. The window period for offshore operations is short and there are many uncertain factors. Once such expensive equipment encounters an accident, the losses cannot be recovered. In the future, we hope to build base stations on the seabed to achieve cluster detection and better serve deep-sea resource exploration, "Liu Jian said.

According to Xu Huixi, "Qianlong 4" is a customized 6000 meter autonomous underwater robot product purchased by the China Ocean Association, which is tailored to meet user application needs. Its main technical indicators have been significantly improved compared to "Qianlong No.1", with better reliability. In 2020, the "Qianlong IV" carried out an ocean survey mission.

At present, "Qianlong 3" and "Qianlong 4" have been handed over to the application unit. The upgrade and renovation of "Qianlong 1" and "Qianlong 2" are nearing completion and will also be delivered later. The continuous application of the "Qianlong" series of underwater robots will undoubtedly make greater contributions to the investigation of deep-sea mineral resources in China.

We are deeply aware that improving the ability to develop marine resources is one of the important characteristics of building a maritime power. As a national team in the field of marine research, which shoulders the mission and responsibility of building a maritime power, we will devote ourselves to research and development, continue to conquer the core key technologies of underwater robot equipment, and make intelligent equipment more serve China's deep-sea resource exploration. "Li Shuo, Deputy Director of Shenyang Institute of Automation, told China Science Daily Represent.

(Originally published in the first edition of China Science Daily on January 25th, 2022)