Scientists Program Largest Swarm of Robots Ever

[humble3d]

Scientists Program Largest Swarm of Robots Ever

MEDIA & MORE VIA THE LINK(S) BELOW...


Alone, the simple little robot can’t do much, shuffling around on three vibrating tooth-pick legs. But working with 1,000 or more like-minded fellow bots, it becomes part of a swarm that can self-assemble into any two-dimensional shape.

These are some of the first steps toward creating huge herds of tiny robots that form larger structures—including bigger robots. Building swarming robots can also help scientists understand collective behavior seen in nature, from bird flocks and fish schools to networks of cells and neurons.

In the past, researchers have only been able to program at most a couple hundred robots to work together. Now, researchers at Harvard University have programmed the biggest robot swarm yet.

“It’s really a big accomplishment,” said roboticist Hod Lipson of Cornell University, who wasn’t involved in the work. “It’s the first demonstration of this swarm robotic behavior at the scale of 1,000 physical robots.” Getting even tens or a hundred robots to work together is difficult, with a lot of algorithmic and technical challenges, he says.

Fancy robots with wheels, odometers, orientation sensors, and cameras can make self-assembly easier, said Mike Rubenstein, the roboticist who led the research team. “But if it’s too complicated, you can’t build a thousand robots.” That would be too expensive and difficult. At the same time, if you make your robots too simple, their capabilities become too limited. “So there’s a difficult trade-off.”

The researchers used robots they designed and built called Kilobots, which aren’t much bigger than a penny. Each one costs $14 in parts and only takes a few minutes to put together—you can even order some for yourself. To program them all at once, the researchers beam down instructions via an infrared light from an overhead controller. The robots communicate with one another by sending and receiving infrared signals. The team programmed 1,024 of these robots to gather into the shape of a star, the letter “K,” and a wrench (watch the robots at work in the video below).

The shape formation begins with four seed robots that act as the origin of a two-dimensional coordinate system. The other robots scurry one-by-one along the edge of the group toward the seed robots. Once the robots sense they’re behind another robot or at the boundary of the shape they’ve been programmed to form, they stop. The newly positioned robots then broadcast their locations so that their bot brethren know where to go. Each robot keeps track of its location and orientation relative to its neighbors.

These kinds of self-organizing algorithms have many applications, such as in driverless cars, Lipson says. Sooner or later, driverless cars will chauffeur us around, he says, and they’re going to need sophisticated algorithms to ensure smooth traffic flow and to avoid collisions.

Eventually, swarming robots could even lead to what’s called programmable matter. Imagine thousands of tiny robots forming whatever three-dimensional structure you want, whether it’s a hammer or a cell phone—a kind of 3-D printing that works like programmable, self-molding clay. “That’s the dream,” Lipson said.

Or, Rubenstein says, these tiny robots can act as biological cells, forming the building blocks for bigger, shape-shifting robots. The idea is that such a robot could take whatever shape is best suited for a particular task. It could assume the shape of a snake to slither across sand, form legs to crawl over rock, or even a wheel to roll up and down a hill. A swimming robot could become more aerodynamic to slice through water. It could even split into two if the task requires it. And, these collective robots would be easily fixed, since ideally every one of the tiny robots would be cheap and replaceable.

Of course, that’s still a long way away, Rubenstein says. For now, he’d like to design robots that can actually attach to one another and form rigid structures. Another area of improvement would be to refine the algorithm so that robots can arrange themselves more quickly. Right now, the robots scuttle around one at a time, taking hours to form a shape. But with an algorithm that allows them to assemble in parallel, then they can shape up faster.

A faster algorithm would also enable even larger swarms of 10,000 robots to self-assemble, which could otherwise take days. But first, there are practical issues. “I would need a bigger table,” Rubenstein said.

Heads up for the gathering robot swarm

Fish gotta school, birds gotta flock, and robots, it seems, gotta swarm. At least, that’s what they’re doing on the workbench of Harvard University computer scientists Michael Rubenstein and Radhika Nagpal and Massachusetts Institute of Technology computer scientist Alejandro Cornejo. Each of their 1024 robots, called Kilobots, is a three-legged disk the size of a U.S. quarter, sporting a single curl of metallic hair. En masse, they form a mechanical multitude an order of magnitude larger than any robot swarm ever built—a possible precursor to future robot work squads choreographed for chores such as cleaning up oil spills.

“That is a beautiful accomplishment,” says Hod Lipson, a roboticist at Cornell University who was not involved with the work. “Really getting a thousand robots to perform in sort of perfect synchrony.”

The idea for swarms of robots working together comes from nature. Army ants link themselves together to form rafts and bridges, and neurons in a brain fire off signals that collectively create intelligence. They do it all by following collective algorithms—shared sets of rules and instructions—and taking their cues from what’s going on around them. Each individual is “just doing its own thing, locally. But fantastic things emerge out of their collective behavior,” Lipson says.

In the past, a group of scientists including Nagpal created small teams of termitelike robots that built simple structures by similarly obeying a shared algorithm. But the robot termites were only a trio. Roboticists have long dreamed of making robotic collectives that could rival natural ones in number and function. Researchers had played around with thousands of virtual robots in computer simulations, but making that vision a reality was no simple task. “Truth is, things rarely behave the way we simulate them,” Nagpal says. What’s more, she adds, “making a thousand robots is really hard.”

The team solved the problem of getting all 1024 robots to communicate by putting an infrared light transmitter and receiver on each robot’s belly and programming them to pulse messages to one another. Their three little metal legs both vibrate, letting the bots scuttle along, and are a charging mechanism. Sitting atop one charging plate with another plate pressing down on the Kilobots’ single metallic hair, every bot can recharge its batteries at the same time. They kept the robots simple, Rubenstein says, because “every penny you spend on each robot becomes $10.00 for the whole swarm.”

The results, described in a paper published online today in Science, are “very simple agents that can self-organize, can collaborate” to create any 2D shape, such as a star or a wrench. When they want to start making a shape, one Kilobot flashes out a signal that passes through the swarm like a game of telephone. The signal robot tells the whole swarm where the original robot is, how to find it, and what shape to make, with it as the starting point. The other robots then figure out where they are by talking to the robots around them and begin filing into place. As in a colony of ants, “there’s no centralized leader per se,” Rubenstein says. “Every robot is just talking to its neighbors and making its own decisions based on what it sees in its environment.”

“This is the holy grail of what we want to do with robots,” says James McLurkin, a roboticist at Rice University in Houston, Texas, who was not involved in the project. He says the Kilobots give scientists a platform to test new ideas and programming on an actual, physical thousand-bot swarm instead of just unreliable simulations. Eventually, that might lead the way to developing real search-and-rescue robot teams or robotic construction crews. “This breakthrough points toward searching the whole ocean for downed aircraft. Dropping robots off in harm’s way, and they build you an airfield. You drop ’em all off in a cave, and they come back with a map,” McLurkin says.

“One interesting future direction is to allow the robots to attach to one another,” Rubenstein says. A bucket of linking robots could be programmed to stitch themselves together into larger Transformers-like tools as well as to roam about in massive teams, he says. Nagpal acknowledges that Kilobots won’t be tackling real-world tasks any time soon. Still, she hopes such applications are coming. “I’d love to build robots like that,” she says.

http://www.wired.com/2014/08/largest-robot-swarm-ever/

http://news.sciencemag.org/technology/2014/08/heads-gathering-robot-swarm?rss=1