Adding wings to a robotic bug helped it run faster and better, but was it enough to achieve takeoff?

Video: A six-legged, 25 g robot has been fitted with flapping wings in order to gain an insight into the evolution of early birds and insects. Published, 18 October, in IOP Publishing’s journal Bioinspiration & Biomimetics, the study showed that although flapping wings significantly increased the speed of running robots, the origin of wings may lie in animals that dwelled in trees rather than on the ground. “A wing assisted running robot and implications for avian flight evolution” (K Peterson, P Birkmeyer, R Dudley and R S Fearing 2011 Bioinspir. Biomim. 6 046008)

Even though the wings significantly improved the running performance of the 10-centimeter-long robot – called DASH, short for Dynamic Autonomous Sprawled Hexapod – they found that the extra boost would not have generated enough speed to launch the critter from the ground. The wing flapping also enhanced the aerial performance of the robot, consistent with the hypothesis that flight originated in gliding tree-dwellers.

The research team, led by Ron Fearing, professor of electrical engineering and head of the Biomimetic Millisystems Lab at U.C. Berkeley, reports its conclusions online Tuesday, Oct. 18, in the journal Bioinspiration and Biomimetics.

Using robot models could play a useful role in studying the origins of flight, particularly since fossil evidence is so limited, the researchers noted.

First unveiled by Fearing and graduate student Paul Birkmeyer in 2009, DASH is a lightweight, speedy robot made of inexpensive, off-the-shelf materials, including compliant fiber board with legs driven by a battery-powered motor. Its small size makes it a candidate for deployment in areas too cramped or dangerous for humans to enter, such as collapsed buildings.

Image right: DASH+Wings showed the possibility of using robotic models to provide insight into biological performance. (Image by Kevin Peterson, Biomimetic Millisystems Lab)

A robot gets its wings

But compared with its biological inspiration, the cockroach, DASH had certain limitations as to where it could scamper. Remaining stable while going over obstacles is fairly tricky for small robots, so the researchers affixed DASH with lateral and tail wings borrowed from a store-bought toy to see if that would help.

The researchers ran tests on four different configurations of the robotic roach, now called DASH+Wings. The test robots included one with a tail only and another that just had the wing’s frames, to determine how the wings impacted locomotion.

With its motorized flapping wings, DASH+Wings’ running speed nearly doubled, going from from 0.68 meters per second with legs alone to 1.29 meters per second. The robot could also take on steeper hills, going from an incline angle of 5.6 degrees to 16.9 degrees.

“With wings, we saw improvements in performance almost immediately,” said study lead author Kevin Peterson, a Ph.D. student in Fearing’s lab. “Not only did the wings make the robot faster and better at steeper inclines, it could now keep itself upright when descending.”

The flapping wings improved the lift-drag ratio, helping DASH+Wings land on its feet instead of just plummeting uncontrolled. Once it hit the ground, the robot was able to continue on its way.

Tree-dwellers vs. ground-runners

The engineering team’s work caught the attention of animal flight expert Robert Dudley, a UC Berkeley professor of integrative biology and researcher at the Smithsonian’s Tropical Research Institute, who noted that the most dominant theories on flight evolution have been primarily derived from scant fossil records and theoretical modeling.

He referenced previous computer models suggesting that ground-dwellers, given the right conditions, would need only to triple their running speed in order to build up enough thrust for takeoff. The fact that DASH+Wings could maximally muster a doubling of its running speed suggests that wings do not provide enough of a boost to launch an animal from the ground. This finding is consistent with the theory that flight arose from animals that glided downwards from some height.

“The fossil evidence we do have suggests that the precursors to early birds had long feathers on all four limbs, and a long tail similarly endowed with a lot of feathers, which would mechanically be more beneficial for tree-dwelling gliders than for runners on the ground,” Dudley says.

The winged version of DASH is not a perfect model for proto-birds – it has six legs instead of two, and its wings use a sheet of plastic rather than feathers – and thus cannot provide a slam-dunk answer to the question of how flight evolved, Dudley explained.

“What the experiments did do was to demonstrate the feasibility of using robot models to test hypotheses of flight origins,” he said. “It’s the proof of concept that we can actually learn something useful about biological performance through systematic testing of a physical model.”—Source: University of California, Berkeley

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Image: This illustration depitcs a section of the exhibit that highlights how modern humans are the one remaining species of a diverse family tree.

The $20.7 million hall will be complemented by ongoing human origins research and education programs, which are all key components of the museum’s broader initiative, “Human Origins: What Does It Mean to Be Human?” The initiative focuses on the epic story of human evolution and how the defining characteristics of the species have evolved over 6 million years as its ancestors adapted to a changing world.

 Visitors to the 15,000-square-foot Hall of Human Origins will be immersed in a unique, interactive museum experience illuminating the major milestones in the origin of human beings and the drama of climate change, survival and extinction that have characterized humans’ ancient past. On entering the exhibition from the Sant Ocean Hall, visitors will travel through a dramatic time tunnel depicting life and environments over the past 6 million years. Visitors will also engage with life-size forensically reconstructed faces of early human species, all designed to provide visitors with a sense of personal connection as they look into the eyes and faces of their distant ancestors.

Image: This illustation shows a section of the exhibit that communicates the message that human characteristics evolved over millions of years.

Other key features in the exhibition include interactive snapshots in time using the actual field sites where research is being conducted, a display of more than 75 skulls (cast reproductions) and an interactive human family tree showcasing 6 million years of evolutionary evidence from around the world, a “One Species Living Worldwide” amphitheater show and a special “Changing the World” gallery, in which visitors can address pressing questions and issues surrounding climate change and humans’ impact on the Earth.

 “The study of human origins is among the most vibrant fields of science and one that draws much public curiosity,” said Rick Potts, director of the Human Origins Program and curator of anthropology at the museum, whose research and vision is the foundation of the Smithsonian’s Human Origins Initiative. “Our hope is that the exhibition will expand knowledge and understanding about our defining cultural and biological characteristics and how those traits emerged during the past 6 million years—one of the most dramatic eras of environmental change in our Earth’s history.”

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Image: 1840 portrait of Charles Darwin by George Richmond

As Darwin’s theories on evolution continue to guide scientific research at the Smithsonian today, it is fitting that Smithsonian Institution Libraries has recently acquired a rare first edition of Darwin’s Geological Observations on the Volcanic Islands, Visited During the Voyage of H.M.S. Beagle, published in London in 1844.

The volume completes the Smithsonian’s collection of Darwin’s three-volume series, Geology of the Voyage of the Beagle, which also includes the volumes:  The structure and distribution of coral reefs (London, 1842) and Geological observation on South America (London, 1846). All three books are now on display in the National Museum of Natural History exhibit Darwin’s Legacy, which celebrates the 150th anniversary of the publication of On the Origin of Species (published Nov. 24, 1859).

In 1831, Darwin, a recent graduate of Cambridge University, embarked upon an adventure as an unpaid naturalist aboard the H.M.S. Beagle.  The Beagle left Plymouth, England on Dec. 27, 1831, and after sailing around the world, returned to Falmouth, England on Oct. 2, 1836. The Beagle’s journey took Darwin to many places, including Tahiti, the Galapagos Islands, New Zealand and Australia. Darwin’s geological work aboard the Beagle brought him his first fame as a scientist. In Tahiti, he developed his theory of the formation of atolls. He proposed that these ring-shaped coral reefs form when the ocean floor gradually subsides beneath an island. The atoll remains after the island has disappeared below the surface of the water. Later investigations confirmed Darwin’s insights.

 Photo: Darwin’s Geological Observations on the Volcanic Islands, Visited During the Voyage of H.M.S. Beagle, on exhibit in Darwin’s Legacy at the National Museum of Natural History.

Published nearly 15 years before On the Origin of Species, the book Geological Observations on the Volcanic Islands, Visited During the Voyage of H.M.S. Beagle, “is an important text in the development of modern geology and in the evolution of Darwin’s thinking on the formation of the earth and the distribution of species,” explains Leslie Overstreet, curator of natural-history rare books at the Smithsonian Institution Libraries.  “SIL’s primary mission is to support the Institution’s scientists and historians,” Overstreet explains. “Global volcanism is a major focus of study at the National Museum of Natural History, and our holdings of published works form a deep, rich resource for researchers.” —Jessica Porter

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