Introduction
SHOAL, the pan-European information and communication technology project, has successfully developed and delivered intelligent robotic fish capable of detecting and identifying pollution in ports and other aquatic areas.
Luke Speller, SHOAL project leader and senior research scientist at BMT Group Ltd, believes that underwater robots will revolutionise the way we manage our oceans. He describes the key areas of major development and the significant role each of the partners have played in bringing these mechanical fish to life. Previously, methods of monitoring pollution and identifying its sources, involved taking water samples which were then sent to a laboratory for testing, the results of which could take weeks to establish. This meant that any remedial action, such as repairing a leak, would be delayed and pollution would continue to make the situation worse. A vessel which had not been appropriately identified as the cause of pollution may then continue its journey spreading contaminants the entire way up a coastline. Either scenario is environmentally unacceptable.
The solution that SHOAL provides
Now, through the use of autonomously controlled robot fish, ports and harbours around the world can receive this information in real-time. SHOAL, a research project managed by BMT Group Ltd and part-funded by the European Union under the Seventh Framework Programme for ICT, has designed and developed these specialised robotic fish. They have sensitive chemical sensors attached to them and are able to identify the source of pollution by working together, using artificial intelligence.
Given the nature of how these systems can be used, it was apt that a fish-shaped robot was chosen, but in fact the choice was not based on aesthetics, but design. The fish shape is a very manoeuvrable, efficient solution due to its small turning circle, allowing the robots to navigate quickly in ports to find pollution, and also avoiding ships and the port infrastructure. It's also low-noise so it does not disturb the environment when outside of busy ports.
BMT hopes that the biomimetic solution will inspire future generations of engineers as it is an example of how we do not need to be constrained by typical designs, but by merging creative ideas with engineering principles, we allow the potential for new possibilities. This removal of boundaries and rules from our thinking are what allows real advances in technology to be made. Weighing approximately 35 kilograms, the fish are 60 centimetres high, 150 centimetres long and 35 centimetres wide. Limited by an acoustic range of a kilometre from the ‘pingers’, the fish can travel 15 kilometres out from the shore station and return without localisation restrictions. The fish can operate for up to eight hours before it needs to return to the shore station to be recharged.
The key developments that made it possible
The last three years has seen no less than five key areas of major development that have helped in the development of the SHOAL solution.
Artificial and swarm intelligence
Importantly, artificial and swarm intelligence technology was developed by BMT Group’s research and development team. This means that each robotic fish has been given artificial intelligence to operate independently, and also as a swarm. It allows each individual robot to be able to manage multiple problems such as; avoiding obstacles, knowing where to monitor pollution, finding the source of a pollutant, maintaining communication distance from the other fish and returning to be recharged. Each individual robotic fish has an array of sensors and external information sources that allows it to navigate its environment. BMT has also created a real-time navigation and control system for a team of three robotic fish which deploys cooperative strategies for the robotic fish team to build a 3D pollution map. The robotic fish can seek, find, identify and report the precise location of pollutants including heavy metals such as copper, lead and phenols. They can also analyse oxygen levels and salinity to ensure the water is a healthy environment for wildlife.
Robotic design
The University of Essex in the UK, built upon its earlier prototype and developed the robotic fish further by making them stronger, allowing them to be able to better survive harsh conditions, provide more power and have a longer battery life. They also developed the ability to incorporate the intelligence, sensing and localisation technologies from the other research partners. Furthermore, the fish now have a jointed tail and use an oscillatory fish-like motion to propel themselves through the water, as well as a weight inside to allow them to dive and rise when required. This provides a quieter solution as opposed to using propellers and allows for high manoeuvrability.
Chemical sensors
The Tyndall National Institute in Ireland has developed novel chemical sensor subsystems which have been incorporated into the robot, enabling the analysis of sea water on board the robotic fish. Using electro-analysis of the water, they are able to calculate the concentration of an array of contaminants in the water.
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