The Norwegian subsea technology company Sperre has developed a revolutionary new generation of remotely operated underwater vehicles (ROVs).
An advanced propulsion system, auto-tracking, and an ingenious multiple-tool platform mean that much is required of the controller, which was developed in collaboration with Data Respons Kongsberg.
A new generation of ROV, which has been given the designation H-ROV (Hybrid-ROV), is now in the final phase of development. This new generation will have a broad area of application because it has a more flexible propulsion system and a tool platform that can be equipped with up to four different tool configurations that can alternate underwater.
"The H-ROV will be particularly suitable for subsea DP and auto-traction operations," said Thor Olav Sperre, owner-director of Sperre AS.
Versatile tool platform
The new tool platform allows the ROV to be equipped with a number of different tool configurations before it is sent down to the working area.
"Previously, the ROV would have to be brought back to the surface to be fitted with a new set of tools," said Sperre. "This new versatile tool platform saves a lot of time, and in practice this means that the deeper the ROV works, the greater the time savings."
The propulsion system, the tool platform and the fact that the various segments can be rotated independently of each other represents no small revolution in the ROV market, which according to Thor Olav Sperre is conservative and lacking in innovation.
"Each of the four thrusters can be rotated through 360 degrees around its own axis. This means that the driving power is radically increased in comparison with traditional ROVs, and the driving power as well as the compensation for current and cable drag can be utilised to the maximum. Our calculations show that up to 100 percent of the H-ROV’s propulsion can be utilised. With traditional ROVs, the degree of utilization is only between 50 and 70 percent," explained Sperre.
The propulsion system is just one of several improvements. The main body itself, with the buoyancy element, can rotate independently of the H-ROVs main chassis and the thruster platform, allowing the H-ROV to simply redefine "fore" and "aft." The result of this functionality is that more equipment can be fitted and that the pilot enjoys a 360-degree view.
"The tool solution (or tooling skid) has been designed in such a way that four sets of tools can be fitted on the surface, each on its own side of a square frame, before the ROV descends to the working area. When the various tasks are to be carried out, the tool frame is rotated independently of the ROV's main structure so that the relevant tool is positioned in front of the defined working zone," explained Sperre.
Extended area of application
The patent is in place in Norway, and Sperre envisages major international potential for the H-ROV.
"This is a design that will extend the areas of application for ROV operations. The H-ROV will be a perfect tool for the offshore industry, research, marine biology and archaeology, environmental studies, and so on. All subsea contractors, especially those engaged in deep-water operations, are likely to save both time and money with the H-ROV," said Sperre.
New brain for the H-ROV
In 2004 Sperre AS developed a controller for dynamic positioning (DP). This solution made considerable demands of the pilot due to hardware limitations and the use of an external mapping system. The new H-ROV needed a new brain, and the time had come to develop a controller that was flexible, offered good performance and that was developed to be upgradeable so that it could be used with future generations of ROVs.
"We wanted to transfer information from the sensors into the ROV controller and allow the ROV to adjust its position itself," said Jesper Nordgård, head of Sperre AS's electronics department.
This demanded a completely new generation of controller, and the company contacted three suppliers for help with developing the new controller, which was named the Hybrid CPU Controller. The controller is central to the control system, marshalling communication with the pilot top-side as well as with the sensors and actuators in the ROV.
On the market soon
The new H-ROV will soon be ready for the market, and Thor Olav Sperre reckons that it will be ready for delivery by the end of 2010. The company is now looking for an R&D partner that can help them to launch the H-ROV on the international market.
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