While the whirligig beetle may not be the most interesting insect to watch for long periods of time, there is a calming effect in its swooning a path atop the water, alternating between motivated sashays and thoughtful drifts, like an ice skater suddenly capable of flight. Their movement will be mimicked in the development of a robot that will no doubt inspire a non-poetic dance craze.
These Size-Undetermined Freakin’ Robots are being developed by Mingjun Zhang, Associate Professor of Mechanical, Aerospace, and Biomedical Engineering at the University of Tennessee, Knoxville. Zhang won the 2011 Young Investigator Award from the Office of Naval Research through the Department of Defense, with whom he’s working to build the prototype. The study was published in the latest PLOS Computational Biology.
“The propulsive efficiency of the species has been claimed in literature to be one of the highest measured for a thrust-generating apparatus within the animal kingdom,” Zhang says, in a direct reflection how little I myself think about animal propulsion. In order to solve the mystery of the insect’s movement, Zhang’s team used high-speed imaging, dynamics modeling, and a series of simulations, revealing some surprises.
The beetle’s three pairs of legs all perform different duties, beating in different directions and working in alternate shifts to achieve their energy-efficient curved trajectories. The directional variation eases the transition from swimming to diving. There is a thin laminae tissue on either side of the swimming legs that expands when the beetle takes off, increasing the surface area and generating more thrust than the legs alone. Furthermore, the legs are able to move in multiple angles and aren’t restricted to locking its legs forward as the beetle moves. It kind of makes our big lumbering legs look simple in comparison, but it’s probably just because our complicated mechanisms are covered in skin.
Not content making Rubber Duckie-complementing bath toys, Zhang will be developing a series of bio-mechanical swimming and diving military robots for the Navy, based on the whirligig’s leg movements. I can’t wait to see those quick flutters ratcheted up in size. It’s a novel purpose, but if the whole D.O.D. thing doesn’t work out, he can always create the most easily destroyable and hard-to-put-together bath toy in history.