ROVworld Subsea Information

Intelligent ROVs picked for advanced habitat research
Date: Tuesday, July 26, 2005 @ 03:23:04 EDT

Marine science is turning to the new generation of intelligent ROVs for demanding survey and sampling research projects.

Latest to lead the trend is the Agriculture and Environmental Science Division of the Department of Agriculture and Rural Development in Belfast. Delivery of their vehicle from Seaeye Marine follows orders from Scottish Natural Heritage and the Environment and Heritage Service Water Management Unit in Co. Antrim.

Marine scientists now expect from their ROVs a high level of sophistication to meet the growing demands of habitat assessment in support of marine conservation, fisheries and aquaculture. Vehicles need to be highly manoeuvrable and responsive to the lightest touch. Image acquisition must be to the highest quality and able to examine and measure the smallest specimen. Finally, when specimens are needed, the most delicate manipulation must be possible. All these tasks must be performed under the most rigorous of operating conditions.

Success for Seaeye has come from their development of a range of vehicles that are lighter, less costly to operate and, through the use of intelligent electronics, better able to do increasingly complex tasks with more sophisticated data acquisition systems.

The Belfast unit, for instance, needed an ROV that could operate at 1000m in strong currents working in coastal waters to the shelf edge. The Seaeye Tiger they ordered will allow them to complete synoptic maps of key areas in GIF format including developing a video database of benthic habitats. Subsequent analysis will indicate sensitivity to fishing, aquaculture and land run off. To achieve this, the Tiger is fitted with a Kongsberg broadcast quality video camera, a digital stills camera and strobe, a Tritech laser image scaling zoom camera and spare interfaces for scientific sensors and an acoustic tracking system.

Scottish Natural Heritage, working under the European Habitat Directive in the search for conservation of biodiversity in Scotland, seeks to identify animals and plants as part of a rolling programme of 34 marine sites. In choosing their Falcon ROV from Seaeye they specified the very best quality video imaging and picked a 3CCD broadcast quality camera with video multiplexed and transmitted over fibre optics in the umbilical. For their second camera they needed image scaling down to 1 mm so chose a Tritech laser image-scaling colour zoom camera. Also important for SNH was the Falcon's manoeuvrability which gives access to those sites with cliffs over 115m deep and where only an ROV such as this can perform the role needed.

The Water Management Unit at Co. Antrim, Northern Ireland, is also undertaking a major biological survey under the requirements of the EU directive. Their study at Ratlin Island will generate a large number of images as they map the seabed habitat. They also chose a Seaeye Falcon which, in addition to survey studies, is used for checking the leg set down of a jack-up barge used for exploration drilling in preparation for the installation of a marine current turbine. With very little slack water at Strangeford Lough and currents of up to 10 knots, the Falcon had to inspect the eight legs in a very short time before recovery back to the surface.

For marine science work the Falcon has the particular advantage of being able to perform tasks using highly sophisticated technology at a low cost thanks to a pioneering ROV concept developed by Seaeye.

The clever idea is to have a range of task-specific modules that can be simply bolted on to the standard-build Falcon ROV and changed in minutes. This means that the core operating vehicle can be easily tailored to perform various specialized tasks, however complex, by using dedicated modules, and at a much lower cost than building a bespoke. The standard Falcon itself can be modified with options that include a second camera, sonar, acoustic tracking systems and single function manipulator.

Typical is the high-specification imaging module provided on the Northern Ireland Falcon that provided a platform and slaved tilt mechanism for larger specialized cameras not normally fitted on ROVs of comparable size. Other bespoke modules could include multi-function manipulators for sample collection in difficult terrain or an inertia navigation module (a spin-off from nuclear submarine technology) for applications such as tunnel exploration and mapping.

Key to the concept's success is Seaeye's development of an advanced distributed intelligence control system that allows the different mission-specific modules to be easily incorporated within a rugged polypropylene open frame that is attached to the core Falcon vehicle.

The distributed intelligence control system incorporates a single RS485 network and portable surface control units and has adapted the USB port concept to sense whichever system is fitted to the ROV.

This eliminates the need for interface cards on the remote vehicle making fault diagnostics easier and, by removing the need for an electronics pod in the vehicle, makes the ROV lighter.

Highly responsive manoeuvrability and best-of-class handling in strong cross currents in both the Falcon and the Tiger is made possible by the use of 4 vectored brushless DC thrusters in an open frame configuration with a single vertical thruster for dive and surface. The thruster package comes with velocity feedback for precise and rapid thrust control.

Formed in 1987, Seaeye Marine based in Fareham, England is the world's leading manufacturer of electrically operated ROVs. In addition to meeting the needs of marine science, their systems are sold globally for use in the offshore oil and gas industry, along with the military and the emergency services.

July 25, 2005


This article comes from ROVworld Subsea Information

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