Reconfigurable robots could make a splash in rescue missions

Researchers from Sheffield University have created an aquatic robot system that could be used for underwater search and rescue operations, or perform inspections inside ageing water pipes.

The robots, developed by a team from Sheffield’s Department of Automatic Control and Systems Engineering (ACSE), can be assembled – and may eventually self-assemble – into arbitrary shapes, allowing them to be customised to meet the changing demands of their task.

Six prototype cubic modules have been assembled with four micro-pumps built into them. They currently float on the surface of water and use their pumps to achieve motion via a process called Modular Hydraulic Propulsion (MHP).

“Rather than using some thrusters that are externally attached to their bodies, the robots move by routing fluid through themselves,” said team leader Dr Roderich Gross. “The fluid can enter and leave the body in a large number of places – the more modules, the more possibilities for the fluid to be routed. This concept could enable underwater robots to move far more precisely than is currently possible.”

The researchers set the robot a task to detect and move towards a light source and it executed the mission with what Gross described as a ‘decentralised brain’.

“Each module contains an identical fraction of it,” he said. “The advantage of this is that all modules are identical, and hence, if a module breaks it can easily get replaced. The modules can also be produced in larger quantities and at a lower price. Another advantage is flexibility. For example, if a robot is split up into two, each part still has a brain.”

Modular Hydraulic Propulsion could offer new solutions to problems requiring reconfigurable systems to move precisely in 3D confined spaces, such as the inspection of underground water pipes. In the future, miniaturised versions of MHP robots may even enter the vascular network to monitor the health of patients or deliver drugs in a targeted manner.

The research was funded by an EPSRC grant and the team is now hoping for additional funding to develop the research further. Gross added that Sheffield’s Department of Civil and Structural Engineering has a 600m long test pipe that the robots could one day be tested in.

“We have not tested yet our system there, because the current modules are too large [8cm side length],” he said. “To fit through the test pipe, the modules would need to be about half of their current size. This is what we hope to achieve in the future.”