In the past few years, the downturn in the offshore oil and gas industry has created a barrier to ROV demand in the industry. However, continued growth in the marine renewable energy industry provides an opportunity for global ROV manufacturers to continue to develop next-generation ROV systems.

In view of this, the “ROV Safe and Effective Operational Practical Guidelines” prepared by the International Maritime Contractors Association (IMCA) has been updated (currently IMCA R004 REV.4), which includes an extended form for ROV based on global ROV. System development has continued to diversify with a clearer definition of classification.

The revised classification is as follows:

the first sort

This ROV is only used for pure observation purposes. It is a relatively inexpensive and portable device that allows customers to perform close-up visual inspections of underwater targets. This type of ROV is usually very compact, so it cannot be used at high flow rates; however, such ROVs can be installed and deployed on a working-level ROV as a slave system. Typical models of this type are:

VideoRay's PRO 4, Tianjin Deep Blue Ocean Equipment Technology Co., Ltd. (hereinafter referred to as Tianjin Deep Blue), White Shark MAX and White Shark MINI.

VideoRay's PRO 4

Tianjin Deep Blue's White Shark MAX

Seaeye Falcon as a ROV master can release the sub-system under water (the ROV of VideoRay in the middle and the Stinger Nano below)

Second class A

Such ROV systems generally have appropriate load capabilities, such as the installation of an auxiliary camera, sensors for investigation and non-destructive testing. Compared to the first type of ROV, this type of ROV has a larger thrust-to-weight ratio to ensure that it can work in applications similar to larger ROVs (such as marine environments, underwater environments with a certain flow rate). . This type of ROV is still very portable and does not require dedicated LARS system support. Typical models of this type are: Tianjin Deep Blue's finless porpoise IV, Seaeye's Falcon, etc.

Ocean Modules V8 Sii

Tianjin Deep Blue's Finless Porpoise IV-A

Second class B

This type of ROV is still an observational ROV, but it already has a strong load capacity, it can be equipped with a light robot to provide light intervention. Although this type of ROV system requires a dedicated LARS system and a box-controlled base station, it only occupies a small part of the area of ​​the ship compared to the third type of ROV, so it can be deployed to more types of ships. Typical models of this type are: Tianjin Deep Blue Dolphin II, ECA H800, Sub-Altantic Mohawk, etc.

Deep Blue Dolphin II

Sub-altantic Mohawk

Third class A

This type of ROV system is the main product type of the underwater industry, and it can be used for most types of underwater work including investigation, measurement, construction, construction intervention. This type of ROV system requires a considerable amount of deck space for deploying its LARS system, box control base station, work shop, etc., so today's DP workboats are better suited for its deployment. Typical models of this type are: Sub-Altantic Comanche, Seaeye's Leopard, etc.

Sub-Altantic Comanche

Third class B

These ROV systems play an important role in the offshore oil and gas industry. They are equipped with large hydraulic power systems for undertaking the shutdown of the BOP (underwater blowout preventer) and at all stages of the rig construction. Typical models of this type are: Oceanering's NEXXUS, Schilling Robotics' HD ROV, etc.

Schilling Robotics HD ROV

SUPPORTER on the Beihai Giants installs natural gas compressors 300 meters underwater

Fourth class A

Such a towed underwater robot system is relatively simple in design and use, and it simply uses a machine to perform a similar furrow operation on the seabed. This simple design and use provides an economical and convenient solution for long-distance underwater cable laying projects, such as along with cross-sea submarine cable laying. Typical models of this type are: SMD's MD3 Plough.

SMD's MD3 Plough

Fourth class B

The crawler underwater robot system will take more time to bury the underwater cable and pipeline than using the towing scheme, but its advantage is that it can achieve more precise control of the cable re-buried depth burying, and The location of the cable is also more precise, and at the same time, such robots have the ability to route cables on rocky seabeds.

Fifth category

This type of robotic system is usually a one-time project for manufacturers to cope with special use scenarios. A typical example is the development of the Rock Grabbers series of underwater robot systems for clearing the seabed area of ​​the Western European seabed and opening the submarine path to facilitate Embed various submarine cables.

Class 6 Class A

Such AUVs can serve a wide variety of missions, from collecting the data needed by marine research institutions to many military uses, such as mine countermeasures. Typical models of this type are: REMUS 100 from Kongsberg, AUV from Orange Deep Blue, and Gavia from Teledyne.

Kongsberg's REMUS 100

Tianjin Deep Blue Orange Shark AUV performs terrain scanning mission in riverside waters

Class 6 Class B

This type of AUV provides a greater load capacity to install more types of probing instruments and sensors, and these AUVs have the potential to intervene in operations, but many of these are constantly being designed and perfected, and in commercial It is forbidden to use.

Bluefin's planned underwater unmanned submersible combat mission system for joint operations and diversified uses

Boeing's ultra-large UUV model Echo Voyager developed for the US Navy

Kongsberg's HUGIN6000

ROV application trends

As the related technologies involving ROVs continue to mature, the use of such "remote control" methods is increasing. The renewable energy industry is the growing industry of ROV applications. For example, the construction of offshore wind power plants requires a long period of time, including installation, maintenance, and maintenance. In these jobs, unmanned submersibles are required for underwater interventions under water (especially at high flow rates and low visibility). Similarly, many of the deepwater operations previously performed on semi-submersible platforms can now be remotely supported using ROVs, significantly reducing implementation costs.

With the continuous development of marine sensor technology, it will undoubtedly promote and expand the application range of ROV and AUV. For example, acoustic positioning and laser technology are used to accurately map seabed terrain and underwater structures, and generate a 3D point cloud data in real time and transmit it to a terrestrial base station. The continued development of underwater acoustic communication technology allows ROV/AUV to communicate directly with underwater control facilities, so that when communication with waterborne communication facilities fails, an additional communication facility coverage can be provided.

Advances in motor drive technology have led to an increase in the number of purely electric ROVs, but such ROVs are typically used in environmentally sensitive areas, such as environmental pollution caused by hydrocarbon leaks. The power consumption of large pure electric ROVs will increase significantly. This power must be transmitted to the underwater ROV body through the umbilical cable, which is also a limiting factor for the development of pure electric ROV. In contrast, the use of hydraulic power as a propeller and power source for the work load is a more efficient way, and in a suitable environmental area, the hydraulic power ROV will undoubtedly take advantage over a period of time.

The latest development is the emergence of an underwater unmanned submersible system that combines the characteristics of ROV and AUV. It shows many advantages in reducing the operating costs of offshore engineering operations. At the level of today's technology, it is entirely possible to permanently deploy an AUV to an underwater "site" and be on standby to accept instructions. But the equipment is long-awaited, and its reliability and maintainability are the key factors for this solution.

In the field of investigation of submarine topography and submarine pipeline routing, this ROV/AUV hybrid system also has considerable capabilities to challenge traditional working-grade ROVs. Although the performance of the sensors that can be carried on the two submersible systems is almost the same, in the dynamic environment under the changing conditions of the underwater, the control decision of the AUV-like system is much faster than that of a ROV flying hand. The system provides a more stable underwater platform for sensors to collect data.

What is the future development of unmanned submersibles? Is the completely unmanned submersible autonomous cruise in various sea areas of the world, or is it using a hybrid unmanned submersible to keep it in automatic flight mode while engineers continuously monitor the state of the submersible? In any case, there is a backup contingency plan when the submersible has an accident under water. The underwater unmanned submersible designer always needs to consider the problem.