Bristol researchers develop robots based on sea creatures

By Emily Barrett, SciTech Editor

Researchers at the University of Bristol have developed robotic units called RoboSalps, based on a type of sea creature. These robots could operate in remote or extreme environments where human control is difficult, such as extraterrestrial oceans.

The robots are inspired by salps, which are tunicates – marine invertebrate animals – and resemble jellyfish. Their life cycle includes an ‘aggregate’ period, in which the individual creatures are attached together in a chain. This has informed the design of the RoboSalps, which can operate as individual modules or join together to form colonies.

This idea of a colony of soft-bodied robots has many advantages. Once joined together, the robots are more stable and easier to control, as well as being more robust - if one module breaks, the whole colony can still move.  Multiple configurations are also possible; for example, three units may be joined in a chain or a triangle shape.

The study is led by Veronica Lo Gatto, a researcher from the Department of Aerospace Engineering. She is a PhD student at the EPSRC Centre of Doctoral Training in Future Autonomous and Robotic Systems (FARSCOPE CDT).

In a press release from the University, Lo Gatto said, ‘Because of their low weight and their robustness, they are ideal for extra-terrestrial underwater exploration missions, for example, in the subsurface ocean on the Jupiter moon Europa’.

There is strong evidence that Europa has an ocean of liquid water beneath its icy surface. Water vapour was detected above its surface in 2019, and its magnetic field implies the presence of an electrically conductive fluid below the surface – such as salt water. This moon remains a subject of intense scientific interest, with NASA’s Europa Clipper mission expected to launch in 2024 to study Europa in more detail. Europa could therefore be a prime candidate for exploration by these marine robots.

Here on Earth, the robots may have promising uses as well. Dr Helmut Hauser of the University’s Department of Engineering Maths cites ‘the exploration of remote submarine environments, sewage tunnels, and industrial cooling systems’ as examples. Of particular interest is the fact that the robots are well-suited for autonomous missions; thanks to a drone propeller, they are able to swim on their own and so a colony may split into multiple segments to explore in different directions, and afterwards assemble in a new configuration.

What is next for the researchers? According to Prof Jonathan Rossiter, a professor of robotics at Bristol, the goal is ‘achieving energy efficient movements close to those observed in biological salps’.

In fact, RoboSalps are not the only robots to be inspired by biology. Other examples include Harvard’s Ambulatory Microrobot (HAMR), inspired by a cockroach, which harnesses surface tension in order to walk on water, or the Bat Bot, designed by a group of researchers at Caltech. This robot is influenced by the complex flying mechanisms of bats and offers more battery efficiency than other drones of its size. In addition, the researchers developed a silicon membrane for its wings to imitate the real wings of a bat; thanks to this, the Bat Bot is able to be used in environments where a quadcopter drone could hurt people or objects.

Such robots are all examples of the power of interdisciplinary scientific development, where biology has informed innovations in engineering. The future of robotics, at Bristol and beyond, looks encouraging.