An underwater robot can delicately propel itself in any direction with its 12 flexible arms, inspired by the flagella of bacteria. Its creators claim it can carry out underwater inspections without endangering humans or wildlife, as propeller-driven robots would.
Flagella are tiny, hair-like protrusions found on many bacteria that can spin clockwise or counterclockwise to create propulsion. 鈥淸Bacteria] have something called a biological motor, which rotates this elongated structure, and this elongated structure produces thrust, and that鈥檚 how bacteria is propelled,鈥� says at Khalifa University in Abu Dhabi, United Arab Emirates. 鈥淲e took this idea and applied it to a macro-scale bacteria, you could say.鈥�
His team鈥檚 underwater drone, named ZodiAq, uses a dozen artificial flagella to generate finely controlled movements in any direction. The core of the robot is 20 centimetres in diameter and the flagella are 30 centimetres long. Each flagellum has a motor at its base that can rotate it when commanded by a small Raspberry Pi computer housed inside the drone. The device also has sensors to detect depth and movement, and an acoustic modem allows it to communicate with a computer on the surface via sound waves.
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鈥溈烀ǘ淌悠祍 say that the propulsion of bacteria is the most efficient propulsion mechanism in that scale, in the small scale, but scaling it up to this big scale makes the mechanism entirely different. [But] it seems to work,鈥� says Mathew.
In experiments, the researchers were able to control ZodiAq to depths of up to 2.5 metres for an hour. Mathew says the robot can steer itself to any point commanded, but it isn鈥檛 fast 鈥� it takes 15 seconds to cover its own body length twice. In maritime surveys where delicacy is prioritised over speed, this wouldn鈥檛 be a hindrance, he says.
The group is now working on creating flagella that are flexible when used for propulsion, but can become rigid and grasp objects when needed. This would allow ZodiAq to not only survey objects and ecosystems, but also interact with them.
Soft Robotics
