Magnetic navigation of an untethered micro device using four stationary coils

We introduce a magnetic navigation of a small magnet using four stationary coils. We used a Maxwell gradient coil to get magnetic propulsion force and three Helmholtz coils to control the moving direction of the magnet in the magnetic navigation. Using a three-channel coil driver with output capacity of 320 A, we performed magnetic navigation of a small NdFeB magnet with the size of 10 mm times 10 mm times 12 mm on a horizontal plane. When navigated with a slow speed of about 1 mm/s, the magnet kept track of any arbitrary navigational path. We expect the proposed magnetic navigation method can be easily incorporated into the system for human applications since it does not use any moving coils.