The BIOROV suite of projects aims to help autonomous surveying of underwater structures, such as offshore wind turbine jackets or mooring system, underwater cables or undersea water turbines.
These artificial facilities are particularly subjected to marine growth (or biofouling) and require regular inspection. Marine growth is a generic term that gathers all the marine species, which colonize underwater components of marine structures. This induces changes in the hydrodynamic loading because of the added mass, the increase of the size (screen effect) and the change of water flow properties around the components (effect of roughness); this phenomenon hence needs accurate quantification in order to plan the maintenance of these structures.
Due to the high uncertainty of this phenomenon over time, underwater inspections are the only mean to update the information at a given time and for updating time-variant models of growth or planning removing. These data will be more and more integrated in a global strategy of monitoring [Decurey et al.,2020]. Until now, such a task is performed either by human divers or through a Remotely Operated Vehicle (ROV), which is deployed from a surface vessel or platform. Typical issues are risk and cost because numerous human operators are involved, in an environment that can get dangerous. It is also difficult to plan regular inspections due to the uncertainty on weather conditions. Moreover, underwater conditions (luminosity, turbidity) have been shown to impact the accuracy of the inspection and consequently the updating of information Decurey et al., 2020].
Autonomous inspection and tracking of marine growth appear as an appealing alternative, as an Autonomous Underwater Vehicle (AUV) can be easily deployed from the sea shore, travel to the underwater structure and deliver the inspection report.
Scientific advances and innovation
In BIOROV-GPS project we will tackle one of the limitations of AUV’s, that is accurate positioning with regards to the considered structure and we quantify the performance on the basis of user needs (quantification of marine growth). The equipment aims to equip the BlueROV robot which has been subject to modifications and a leak test.
The project targets the acquisition of:
- A GPS and its 3 beacons for global geo-positioning (CAD relationship);
- An instrumented gauge allowing images to be badged at the ideal distance (the automatic calculation and stabilization software is developed as part of the GOROV project funded by the Carnot Mers Institute);
- An electronic card adaptable to any ROV and integrating all the contextual data (turbidity probe, depth, GPS coordinates, distance badge);
- A station equipped with coupons of beacon supports for quality tests in the basin or at sea (tests carried out as part of the GOROV project funded by the Carnot Mers Institute).
Expected technical and economic impact
The BIOROV-GPS project will make it possible, via the continuity of the development of a unique and differentiating know-how on the automatic analysis of bio-colonization by ROV (AuV), to improve the quality of the monitoring of anchor lines and umbilicals, particularly sensitive to bio-colonization, and which present technical specificities and issues in terms of security.
Key project milestones
- 2021 - Acquisition of equipment