CORDIS - EU research results

Autonomous Robotic System for the Inspection of Mooring Chains that Thether Offshore Oil Gas Structures to the Ocean Floor.

Final Report Summary - CHAINTEST (Autonomous Robotic System for the Inspection of Mooring Chains that Thether Offshore Oil Gas Structures to the Ocean Floor)

The objective of CHAINTEST was to overcome the limitations of current inspection working practices on chains used in the mooring systems for floating offshore oil and gas production platforms obviating the need for human inspectors, and thereby increasing inspection reliability. The aim was therefore to develop an autonomous vehicle capable of moving along the chain, above and below water, carrying out inspection tasks while the chain is in-situ, eliminating the need to bring the chain on board.

The main components of the system include:
- the development of a cleaning system to remove sufficient marine growth and rust scale from the surfaces of the chain for inspection;
- developing a vision system that can measure chain link dimensions and conduct visual inspection;
- developing novel non-destructive techniques, sensors and systems that will detect fatigue cracks and corrosion with the minimum of surface preparation and probe scanning and on surfaces hidden between chain links. The system will use alternating current field measurement (ACFM) to find surface breaking cracks at the weld, and ultrasonic testing for cracks originating at the inter-grip region;
- crawling vehicle.

In the first year the system specification and requirements document were completed. This was an on-going document to be updated throughout the project duration. The proofs of concept for the functional units were also completed in year 1 and the design and build of the devices by which the functional units are deployed on the chain by the crawler. The design of the robotic crawler was also started during this period.

In year 2 there were a number of changes / improvements to the specifications of the system and these have been incorporated in the final version of the system specification and requirements document. Year 2 of the project also saw:
- completion of the control software for the slider and robot arm;
- completion of the MMI with all hardware components and software;
- integration of the cleaning system and the robot arm and the integration of the ACFM and PAUT probes to the slider being demonstrated and tested before the final integration of both robot arm and slider mechanism onto the crawler;
- the laboratory trials of the integrated system were abandoned due to time constraints and to ensure that the field trials could take place. Field trials were conducted at an indoor seawater facility at Brest in France.

The consortium has not yet fully agreed upon details of publications that will complete dissemination of the results whilst at the same time safeguarding the legitimate business interests of the partners. The consortium anticipates that there will be several key exploitable deliverables in the period following completion of the project.