Robot Swarms – Shape-Shifting Robot Forms from Magnetic Swarm – 11016
Swarms of robots that use electromagnetic forces to cling together and assume different shapes are being developed by US researchers. The grand goal is to create swarms of microscopic robots capable of morphing into virtually any form by clinging together.
Seth Goldstein, who leads the research project at Carnegie Mellon University, Pittsburgh, in the US, admits this is still a distant prospect. However, his team is using simulations to develop control strategies for futuristic shape-shifting, or “claytronic”, robots, which they are testing on small groups of more primitive, pocket-sized machines. These prototype robots use electromagnetic forces to manoeuvre themselves, communicate, and even share power.
No Moving Parts
One set of claytronic prototypes were cylindrical, wheeled robots with a ring of electromagnets around their edge, which they used to grab hold of one another. By switching these electromagnets on and off, the so-called “claytronic atoms” or “catoms” could securely attach and roll around each other .
The robot’s wheels were not powered, so they had to rely entirely on their magnets to manoeuvre themselves around. “These were the first mobile robots without any moving parts,” says Goldstein. They also used their electromagnets to share power, to communicate, and for simple sensing. Since using magnetic forces are less efficient at smaller scales, the team has now begun experimenting with electric forces instead.
The latest prototypes are box-shaped robots dubbed “cubes” that have six plastic arms with star-shaped appendages at the end of each.
These stars have several flat aluminium electrodes and dock together, face on, using static electricity. Electrodes on different stars are given opposing charges, which causes the stars to attract each other. Once connected, no power is needed to hold the stars together.
Tests have shown that it is possible to send messages and power to other cubes over the same links. “Our hope is to assemble around 100 cubes to experiment with ideas,” Goldstein says.
Rob Reid at the US Air Force Research Lab is collaborating with the Carnegie Mellon team to develop even smaller prototype robots. Reid and colleagues can fold flat silicon shapes into 3D forms as little as a few hundred microns diameter. “We will drive those using electric forces too, by patterning circuits and devices into the silicon design,” Goldstein says. He predicts that by the summer of 2008 they will have prototypes capable of rolling themselves around this way. Modularity is a popular theme with robotics researchers around the world.
“The physical mechanism for docking different pieces is really tough to do,” says Alan Winfield, who works on artificially intelligent swarms at the Bristol Robotics Laboratory in the UK. “Most use mechanical latches with hooks.” Although these physical connections are complex, they do not need power, Winfield points out, unlike magnetic connections.
Using electromagnetic forces may make more sense at smaller sizes, he adds. “My guess is that electrostatic connectors will come into their own on the micro scale where less power is needed to have a large effect,” he says. But software, not hardware, may be the biggest challenge facing researchers working on swarms of robots, he says: “Right now we just don’t know how to design a system that produces complex overall behaviours from a group of simple agents.”
Ultimately, Goldstein believes his claytronic robots may one day achieve this, and much more: “I’ll be done when we produce something that can pass aTuring test for appearance,” he says. “You won’t know if you’re shaking hands with me or a claytronics copy of me.”