But here’s an interesting twist to the tale. A recently designed robot at the Biomimetic Millisystems Lab at UC Berkeley is now shedding light on flight evolution.

A research team, led by Ron Fearing—we highlighted some of his early biomimicry work a few years ago here—wanted their robotic cockroach, DASH, to move faster. DASH is a lightweight, speedy robot made of inexpensive, off-the-shelf materials first launched in 2009. Its small size makes it a candidate for deployment in areas too cramped or dangerous for humans to enter, such as collapsed buildings.

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,” says 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 engineering team’s work caught the attention of animal flight expert Robert Dudley, a UC Berkeley professor of integrative biology, 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,” says Dudley.

Dudley said that 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.

“It’s still notable that adding wings to DASH resulted in marked improvements in its ability to get around,” Fearing adds. “It shows that flapping wings may provide some advantages evolutionarily, even if it doesn’t enable flight.”

Their research was published online today in the journal Bioinspiration and Biomimetics.

Image by Kevin Peterson, Biomimetic Millisystems Lab

Which leads us to the latest headline, rock and roll robots inspired by caterpillars.

Some caterpillars have the extraordinary ability to rapidly curl themselves into a wheel and propel themselves away from predators. This highly dynamic process, called ballistic rolling, is one of the fastest wheeling behaviors in nature. (You can see a great video of ballistic rolling on YouTube.)

Researchers from Tufts University saw this behavior as a way to give soft robots more speed and power. The results of their study are published today in Bioinspiration & Biomimetics.

To simulate the movement of a caterpillar, the researchers designed a 10cm long soft-bodied robot, called GoQBot, made out of silicone rubber and actuated by embedded shape memory alloy coils. It was named GoQBot as it forms a “Q” shape before rolling away at over half a meter per second.

The GoQBot was designed to specifically replicate the functional morphologies of a caterpillar, and was fitted with 5 infrared emitters along its side to allow motion tracking using one of the latest high-speed 3D tracking systems. Simultaneously, a force plate measured the detailed ground forces as the robot pushed off into a ballistic roll.

In order to change its body conformation so quickly, in less than 100 milliseconds, GoQBot benefits from a significant degree of mechanical coordination in ballistic rolling. Researchers believe this coordination is mediated by the nonlinear muscle coupling in the animals.

The researchers were also able to explain why caterpillars don’t use the ballistic roll more often as a default mode of transport; despite its impressive performance, ballistic rolling is only effective on smooth surfaces, demands a large amount of power and often ends unpredictably.

Not only did the study provide an insight into the fascinating escape system of a caterpillar, it also put forward a new locomotion strategy that could be used in future robot development. According to Science News,

Robots similar to GoQBot may someday aid in search and rescue operations that require both crawling through tight, dangerous spaces and moving across flat ground.

Image courtesy of Huai-Ti Lin

That’s not aliens speaking to humans, but rather scientists speaking to worms, Caenorhabditis elegans, to be exact.

Poor C. elegans. It’s often researchers’ favorite choice because of its optical transparency and its well-defined nervous system of exactly 302 neurons. This time two different groups are using optogenetics, a way to control cell function with light, to manipulate the worms locomotion and behavior.

A group of scientists from Harvard, the University of Pennsylvania and the University of Massachusetts Medical School have come up with CoLBeRT (Controlling Locomotion and Behavior in Real Time) that uses colored lasers to control the worm while it’s moving.

“This optical instrument allows us to commandeer the nervous system of swimming or crawling nematodes [worms] using pulses of blue and green light—no wires, no electrodes,” says Aravinthan Samuel, a professor of physics and affiliate of Harvard’s Center for Brain Science. “We can activate or inactivate individual neurons or muscle cells, essentially turning the worm into a virtual biorobot.”

“If you shine blue light at a particular neuron near the front end of the worm, it perceives that as being touched and will back away,” says co-author Andrew M. Leifer, a PhD student also in Harvard’s Department of Physics and Center for Brain Science. “Similarly, blue light shined at the tail end of the modified worm will prompt it to move forward.”

(A video is of this mind-control is available here.)

By stimulating neurons associated with the worm’s reproductive system, they were even able to rouse the animal into secreting an egg.

A team from the Georgia Institute of Technology found that by using LCD projectors, they could also manipulate the worms’ movements. Apparently, according to Science News there are benefits to both technologies. CoLBeRT works as the worm is moving, and the Georgia Tech system has more precise targeting.

Both studies are published in the recent edition of Nature Methods. A subscription is needed to read the articles (Harvard et al and Georgia Tech), but an entire feature on optogenetics is available for free.

Image: Leifer et. al. / Nature Methods