Deep water robots

Citation

Loughlin, C. (2010), "Deep water robots", Industrial Robot, Vol. 37 No. 5. https://doi.org/10.1108/ir.2010.04937eaa.001

Deep water robots

Article Type: Editorial From: Industrial Robot: An International Journal, Volume 37, Issue 5

The theme for this issue is non-destructive testing (NDT) and we need look no further than the front pages of our newspapers to witness the failure of an engineering component that may have been avoided had more NDT taken place.

The explosion at the Transocean Deepwater Horizon oil rig led to its sinking on 22 April 2010 in 1,500 m of water in the Gulf of Mexico. In total 11 people died in the explosion and subsequent fires.

The rig was leased to BP and the international press has been quick to hold BP responsible for the disaster and for footing the bill for the clean-up operation that is currently in progress.

It is probably just as well that BP has deep pockets. The cost of fixing the problem is likely to run into billions, but is it really possible to measure the true cost in dollars alone? Nature is remarkably resilient but it cannot be expected to recover from such an onslaught.

When the explosion occurred the rig was engaged in the final casing of the drilled hole with cement. The sinking of the rig and consequent mangling of the sea-bed apparatus gave rise to an oil leak estimated at 40,000 barrels a day.

I do not envy the engineers tasked with stopping the leak, but I hope they have a number of submersible robots to lend a hand.

When a disaster occurs on land it is not long before people are seen scurrying over the wreckage and bulldozers go in and heavy lifting gear is deployed to clear the disaster site. There would not be a lot of scurrying going on at 1,500 m below sea level.

Fortunately, the oil industry has been using unmanned submersible vehicles remote operated vehicles (ROV) that are often equipped with one or more robotic arms that are teleoperated from the surface. Most of these are connected via an umbilical to a ship on the surface and the umbilical is used to provide power for the ROV and communication links.

These ROV are designed to be versatile and are typically used for inspection of subsea installations and also for manual tasks such as the turning on and off of valves. ROVs come in a variety of shapes and sizes but most are about the size of a van. Some have tracks and are designed for sea-bed activities, while others just have skids and are largely free-floating.

The robots arms are typically hydraulically powered and have five to six degrees of freedom and often carry specialist end-effectors for operations such as cutting cables, turning valves (with torque control) and general purpose grippers. They are not designed for heavy lifting themselves but they can be used for attaching heavy lifting cables to submerged structures which can then be pulled away by a crane on the mother ship.

It will always be easy for the general public to pass judgement that more should have been done to prevent the disaster happening in the first place, and that bigger, stronger specialist equipment (like underwater bulldozers and cranes) should have been available on a few hours’ notice.

Clearly more should have been done, and clearly there is always scope for being better prepared, but how much more of a mess would we be in if submersible robots, and their skilled pilots had not been available?

Clive Loughlin