SRI’s microworkers are simple: just small magnetic platforms with simple wire arms on top. They can move only when placed on a surface with a specific pattern of electrical circuits inside. Sending current through the coils beneath exerts a force on the magnets and steers the robots around. Wong-Foy has written software to do that, and used it to choreograph the movement of over 1,000 tiny robots in a complex circulating pattern. That shows it should be possible to have them work in large teams, he says.I'm waiting for the ones that can change from a chaotic mass into a battle-robot.
The robots’ wire arms are unable to move independently. But creating teams of robots with different types of arms makes it possible to do complex work.
Building a truss structure requires three types of workers. One operates a kind of toothpick dispenser, pushing a lever to release a toothpick-sized carbon rod. Another robot dips its arms into a water trough to put droplets on the ends of its arms, and then uses surface tension to pick up the rod. A third robot visits a glue station, dipping its arms and then applying the glue to the structure under construction. Finally, the robot that picked up the rod presses it into place and waits for an ultraviolet light to switch on to cure the glue. Then it can withdraw to pick up a new rod.
The software controlling the robots can also move the platform they are sitting on. It moves the platform each time a new layer is complete so the robots’ working space stays the same as the structure they’re building grows.
Much like 3-D printing technology, microrobots promise to be a more efficient way to make complex objects in small quantities than conventional mass-production technology, says Mahoney. That’s partly because the microrobots can be reprogrammed to do completely new tasks, and partly because they’re inexpensive. “We sometimes call this megahertz manipulation,” he says. “We can think of manipulation at rates we’re used to seeing in information processing.”