Meet the flying machine that was inspired by a jellyfish

(Video courtesy of Leif Ristroph)

Leif Ristroph wanted to build the “simplest possible” flying machine. The applied mathematician at New York University glued together several tubes of carbon fiber to build this: a sphere with four wings attached to it that propels it as a jellyfish swims.

The flyer is only about eight centimeters in diameter — small enough to fit in the palm of your hand — and its mass is only about two grams, the equivalent of two paper clips.

Half of the mass is the motor, a commercially available component about the size of the vibrator in a phone. There’s no battery on board. For the time being, the flying jellyfish is tethered to a power cord.

(Photo courtesy of Leif Ristroph)

What’s most remarkable about the device, though, is that even though it has absolutely no circuitry and no sensors, it manages to keep itself upright in the air. That’s apparently a physical property of the arrangement of the wings that Ristroph says he can’t fully explain, but he hopes it will allow his prototype to evolve into a new generation of very small and inexpensive drones.

Researchers have built slightly larger machines with impressive stability and control. Raffaello D’Andrea and his team at the Swiss Federal Institute of Technology in Zurich are well known for their ”robotic athletes,” which have four helicopter rotors. The machines can catch a ball and perform other autonomous feats of balance and coordination.

The problem is that conventional propellers are ineffective at small scales, Ristroph explains. Other groups have tried to mimic birds and insects, designing robots with wings that flap. The Harvard Microrobotics Laboratory has built a device even tinier than Ristroph’s that resembles a three-legged mosquito.

Ristroph, though, wanted to try something different. “My initial thinking was basically, ‘Okay, insects beat their wings like this. Birds beat their wings like that. Everyone else is building their robots to copy that,’ ” he said. “Let me think of new ways to fly.”

He and his colleague, Stephen Childress, have considered a number of outlandish designs, including a machine with a single, conical wing that Ristroph believes could theoretically keep a machine aloft.

The flying jellyfish was particularly exciting. 

The device would right itself in response to disturbances. Flying machines modeled on insects typically require a computer on board or fins of some kind to maintain their stability, but Ristroph wanted to do away with all of those systems entirely. Doing so would make the machine lighter, which in principle would allow for an even smaller motor and a cheap, miniature drone.

Of course, any practically useful version of the jellyfish would have to carry a small battery and a navigation system — right now, all the navigation controls are manual — but Ristroph is optimistic those problems could be solved.

(Photo courtesy of Leif Ristroph)

A more difficult problem is explaining the machine’s stability in the air. It will wobble and flit back and forth in flight, like a moth, but never stalls. Each deviation is compensated for somehow, and the jellyfish stays aloft.

Ristroph wrote a list of formulas to account for the device’s behavior, but he didn’t find them persuasive.

“The assumptions I make in the model don’t seem to be justified,” he said. It’s a concession you don’t often hear from researchers.

He envisions flying jellyfish that cost 50 cents each. They could be deployed to monitor air quality, or they could just be disposable toys. “If someone steps on it, it’s fine,” he said.

He isn’t particularly excited about the possibility of a version of his jellyfish being used by the military, and he isn’t comfortable with the Obama administration’s use of drones. But, he said, “Having good drones could, overall, save lives also. I know it’s a big, thorny issue.”

Ristroph demonstrated the device at a conference Sunday, and he’s hoping other researchers will help him figure out why it works.

ORIGINAL: Washington Post

By Max Ehrenfreund
November 25 at 8:20 am

The Rise of Artificial Intelligence

ORIGINAL: 33rdSquare

July 11, 2013

The PBS online series Off Book recently looked at artificial intelligence and asked experts Gary Marcus, Robin Hanson and others about how it may evolve into the future and possibly merge with humanity.

Artificial intelligence is an ever evolving goal for researchers, and the object of endless fascination for writers, filmmakers, and the general public. But despite our best science fiction visions, creating digital intelligence is incredibly difficult.

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The universe is a very complicated place, and humans have had millions of years to evolve the ability to navigate and make sense of it. Contemporary attempts to create AI have us looking more at how our own brains work to see how a computer could simulate the core activities that create our intelligence.

No matter how we get there, it is certain that artificial intelligence will have tremendous impact on our society and economy, and lead us down a path towards evolving our own definitions of humanity.

Produced by PBS Off Book, the video features, Ernest Davis, Department of Computer Science, NYU; Yann LeCann, Center for Data Science, NYU; Robin Hanson, Future of Humanity Institute, Oxford; and Gary Marcus, Department of Psychology, NYU.

Off Book is a web-original series from PBS Arts that explores cutting edge arts and the artists that make it. Episodes range from video games to typography, internet memes to steampunk culture.

SOURCE PBS Off Book

It’s (Almost) Alive! Scientists Create a Near-Living Crystal

ORIGINAL: Wired

BY BRANDON KEIM

01.31.13

Three billion years after inanimate chemistry first became animate life, a newly synthesized laboratory compound is behaving in uncannily lifelike ways.

The particles aren’t truly alive — but they’re not far off, either. Exposed to light and fed by chemicals, they form crystals that move, break apart and form again.

“There is a blurry frontier between active and alive,” said biophysicist Jérémie Palacci of New York University. “That is exactly the kind of question that such works raise.”

Palacci and fellow NYU physicist Paul Chaikin led a group of researchers in developing the particles, which are described Jan. 31 in Science as forming “living crystals” in the right chemical conditions.

Their experiments are rooted in the researchers’ interest in self-organizing collective behaviors, which are easier to study in controlled particle form than in schooling fish or flocking birds.

Each particle is made from a microscopic cube of hematite, a compound consisting of iron and oxygen, sheathed in a spherical polymer coat. One corner is left exposed.

Under certain wavelengths of blue light, hematite conducts electricity. When the particles are placed in a hydrogen peroxide bath under blue light, chemical reactions catalyze around the exposed tips.

'There is a blurry frontier between active and alive.'As the hydrogen peroxide breaks down, concentration gradients form. The particles travel down these, aggregating into crystals that also follow the gradients.

Random forces pull the crystals apart, but eventually they merge again. The process repeats again and again, stopping only when the lights go out.

The ultimate goal of the work is to study how complicated collective behaviors arise from simple individual properties, perhaps informing molecular self-assembly projects, but it’s hard not to think about the origin-of-life implications.

“Here we show that with a simple, synthetic active system, we can reproduce some features of living systems,” Palacci said. “I do not think this makes our systems alive, but it stresses the fact that the limit between the two is somewhat arbitrary.”

Chaikin notes that life is difficult to define, but can be said to possess metabolism, mobility, and the ability to self-replicate. His crystals have the first two, but not the last.

Some scientists think that life’s building blocks once existed in such a form, bouncing back and forth for millions of years until coalescing in configurations that possessed the ability to copy themselves.

Add slight imperfections in the copies — mutations, in other words — and the necessary conditions for natural selection and evolution would be fulfilled.

Inasmuch as it’s possible to say what might have happened billions of years ago, the rest was evolutionary history.

As for what’s happening now in Palacci and Chaikin’s lab, a particle currently under development isn’t mobile, but it has a metabolism and is self-replicating.

“We’re working on it,” Chaikin said.

Citation: “Living Crystals of Light-Activated Colloidal Surfers.” By Jeremie Palacci, Stefano Sacanna, Asher Preska Steinberg, David J. Pine, Paul M. Chaikin. Science, Vol. 339 No. 6119, 1 February 2013.