A new robot created by researchers at the University of Bristol has the mission of cleaning ponds and lakes. Powered by the microbes it scoops up from the water and digests, it doesn’t need any recharging to keep going. The Row-bot is inspired by the water boatman insect and uses a similar mechanism to glide across the surface of water, in the robot’s case, a paddle powered by a 0.75 Watt DC motor. Both bug and robot maximize surface area when making a power stroke and then minimize surface area during the recovery stroke to have the most efficiency.
The Row-bot is a essentially a fuel cell powered by electricity that is generated solely by bacteria living inside the device. The beauty of this particular bacteria-powered fuel cell, however, is the means by which the tiny organisms living in its gut generate that electricity. The Row-bot has four tiny buoyant stabilizers for feet and two paddles that extend from the middle of its body. While the feet keep Row-bot afloat, the paddles send it skimming across the surface of a body of water. The device takes water into a cavity in its housing as it moves, where electrogenic bacteria digest pollutants found within the water. The byproducts of that digestion are carbon dioxide and electricity, which in turn fuels the Row-bot and keeps it moving.
“We present a design for an energetically autonomous artificial organism, combining two subsystems; a bioinspired energy source and bio-inspired actuation,” the researchers wrote in a paper covering their work on Row-bot. “The work is the first demonstration of energetically autonomy in a microbial fuel cell (MFC)-powered, swimming robot taking energy from it’s surrounding, aqueous environment. In contrast to previous work using stacked MFC power sources, the Row-bot employs a single microbial fuel cell as an artificial stomach and uses commercially available voltage step-up hardware to produce usable voltages.” The team continued, “The energy generated exceeds the energy requirement to complete the mechanical actuation needed to refuel. Energy production and actuation are demonstrated separately with the results showing that the combination of these subsystems will produce closed-loop energetic autonomy. The work shows a crucial step in the development of autonomous robots capable of long term self-power.”
The robot also features a “stomach” that houses a microbial fuel cell (MFC) that runs on bacteria extracted from the water and feeds electricity to the motor. Within the MFC, the bacteria is broken down into carbon dioxide, protons, and electrons which the fuel cells uses to generate electricity. The robot ingests some water from the lake or pond it’s floating on and then the fuel cell generates electricity from the bacteria in the water. This provides enough energy for a few strokes of the paddle. As it glides across the water, more water is taken into the “stomach” and the process keeps repeating, letting the Row-bot move around the water continuously. The parts were created using a 3D printer for the frame with an elastic membrane stretched around the body. The next steps are adding monitoring and control systems that would allow the robot to be used for environmental sensing and clean-up projects. In the future, the Row-bots could be deployed in bodies of water to monitor for pollution or pathogens and then, outfitted with the right tools, immediately take steps to remove pollutants or improve the water quality. It’s a scientific breakthrough that could have a dramatic impact on the environment.
For more information please visit: www.bristol.ac.uk
