Students at Carnegie Mellon University have employed external magnetic fields to controllably position and orient a magnetic micro-robot. They demonstrated this approach in the 2007 and 2008 RoboCup Nanogram Demonstrations. Imagine a mechanical Pelé or David Beckham six times smaller than an amoeba playing with a “soccer ball” no wider than a human hair on a field that can fit on a grain of rice. RoboCup is an annual international competition designed to foster innovations and advances in artificial intelligence and intelligent robotics by using the game of soccer as a testing ground. National Institute of Standards and Technology (NIST) hopes that a competition between the smallest robots in RoboCup history will show the feasibility and accessibility of technologies for fabricating MicroElectroMechanical Systems (MEMS), tiny mechanical devices that are built onto semiconductor chips and are measured in micrometers (millionth of a meter). The CMU team uses five electromagnetic coils surround a working volume, wherein the magnetic micro-robot resides. Four of the coils are in-plane with the micro-robot, and one coil provides an orthogonal clamping force. Large DC magnetic field gradients are developed using the coils, which employs a force onto the micro-robot. The robot also experiences a magnetic torque; combined with a pulsed magnetic field, the micro-robot experiences a continuously rocking motion. This, in effect, induces stick-slip behavior in the robot resulting in translation. By varying the pulsing frequency, control of micro-robot velocity is achieved.
