‘ALIVE’- new autonomous vehicle tackles expanding undersea applications
The EU-funded ALIVE project is developing a new autonomous underwater vehicle (AUV) that, unlike conventional AUVs, features automatic docking and manipulation capabilities.
Decades in development by military and research institutions around the world, the commercially viable AUV has only recently become a reality. High-quality surveys are the most common use for AUVs today, but a major EU project is now working on adding intervention tasks to the repertoire.
What the terms mean
ROV: Remotely Operated Vehicle – linked to a surface support vessel and operated through direct cable link, ROVs can carry out many underwater tasks.
AUV: Autonomous Underwater Vehicle – these vehicles are self-contained untethered devices that, until now, have performed a limited range of non-invasive, mainly survey-related tasks.
AUV or ROV?
While the vast majority of ad hoc ROV interventions involve relatively simple tasks such as video/sonar inspection, opening or closing of a faulty valve, checking for hydrocarbon leaks or light maintenance repair, they can be enormously costly. A single such operation carried out at a depth of 1,500 metres will typically cost in the region of €250,000. The main expense in these ‘light interventions’ is the support vessel to which the ROV must remain physically linked.
The ALIVE (Autonomous Light Intervention VEhicle) project, funded under the EU’s FP5 GROWTH Programme, aims to broaden the scope of tasks carried out by AUVs as opposed to ROVs. In doing so, project partners are addressing the issue of economically carrying out light intervention tasks on standard, un-modified underwater structures without the need for long and heavy umbilicals and costly support vessels.
Alone and unhindered
The ALIVE vehicle can be launched from any suitable vessel of opportunity and proceeds physically independantly under the supervision of an operator, via acoustic modem, to a pre-designated point some ten metres away from the work site.
Once there, on-board sonar and video units lock onto and appraise the structure, sending back images to the surface. The vehicle then proceeds to the structure and latches on using dedicated hydraulic grabbers. A full-function manipulator carries out the required tasks using a series of internal pre-programmed commands triggered and validated by the surface operator.
When the task is completed, ALIVE returns to the surface and is recovered – again, no need for a support vessel or cables.
Successful trials – expanding applications
Following a series of tank and shallow water tests carried out in the summer of 2003, sea trials of ALIVE have now been successfully performed off the French Riviera. ALIVE coped well with difficult sea conditions, docking with a subsea structure and carrying out pre-programmed operations, including opening and closing valves with its hydraulic arm.
Project coordinators at France’s Cybernetix say the success of the sea trials is a major step towards autonomous inspection, maintenance and repair operations using AUVs.
Additional applications now being envisaged include assistance in rescue operations, archaeological missions, hazardous materials collection and any other type of intervention where a light vehicle, cost-effective and easy to mobilise, can replace an ROV.