Manta motion marvel
Robotics engineers want to copy the manta ray—a creature that swims “with mesmerizing ease and grace”—in their designs for underwater robots.1
“Mantas are everything one could want in an autonomous underwater vehicle (AUV)” wrote a commentator in Science journal, describing it as “the envy of engineers”. Consider the manta’s manoeuvrability, for example—currently the best robotic submarines have a turning radius of about 0.7 body lengths but the manta’s is just 0.27 body lengths. And while other marine organisms have already inspired significant advances in AUV design,2,3 the powerful-yet-smooth ‘ride’ of the manta is now recognized as a particularly desirable target for robotic mimicry.
Helping to spearhead the research thrust is Adam Summers, a comparative biomechanist at Washington State University: “I’ve thought for a long time that the people who are interested in robotic mimicry were missing the boat in not looking at manta rays.” He pointed out that in contrast to the manta, the fish species that engineers have thus far tried to copy swing their body from side to side, a mode of motion “that’s not very handy if you are trying to stuff [instruments] inside.”
But it was only after filming more than 36 hours of manta manoeuvres that research teams began to understand just how “incredibly challenging” their quest to mimic manta fin movement would be. “The motion is far more complicated than what we find from a dolphin or tuna,” explained biologist Frank Fish, of West Chester University. The manta’s wing-like fin not only flaps up and down but also undulates, sending a traveling wave from the front to the rear of the fin. “This undulatory part of the swimming is really the most important part of it,” explained Alexander Smits, a fluid mechanics expert from Princeton University, also pointing out that it provides four times as much propulsive force as the flapping motion does.
However, understanding how a manta moves isn’t the same thing as successfully copying it. So far, even with topline researchers collaborating across multiple universities and funded by multi-million dollar research grants, progress towards manta-like propulsion (in common with other biomimetics4 efforts) has been dogged by “hiccups and bumps”. The experimental manta-bots still fall way short of the engineers’ stated goal: to produce a flexible mantalike wing that can be controlled accurately. But no-one would deny that the researchers’ faltering prototypes were designed, and intelligently so. How much more respect and honour, then, should be accorded the manta’s Maker?
References and notes
- All quotes and manta research information in this article sourced from: Pennisi, E., Bio-inspired engineering: manta machines, Science 332(6033):1028–1029, 2011 | doi: 10.1126/science.332.6033.1028. Return to text.
- For example: Trafton, A., MIT team building robotic fin for submarines, web.mit.edu, 30 July 2007; also see Catchpoole, D., Submarines with fish fins? Creation 31(3):22–23, 2009; creation.com/submarines. Return to text.
- Wakefield, J., Mimicking Mother Nature, Scientific American 286(1):24–25, 2002; see also Sarfati, J., ‘Primitive’ cell inspires advanced robot mini-sub, creation.com/microhunter. Return to text.
- The list of organisms in nature that have inspired engineers to copy them is growing ever longer. See, e.g., creation.com/biomimetics. Return to text.