Harnessing magnetics to control micro-entities
Goal
To employ external magnetic fields to controllably position and orient a magnetic micro-robot. We demonstrate this approach in the 2007 RoboCup Nanogram Demonstration.
Approach
Four magnetic coils in Maxwell spacing surround a playing field, where a micro-robot resides. Large DC magnetic field gradients are developed using the coils, which employs a force onto the micro-robot. The magnetic field can be continuous, and thus exert a constant force onto the micro-robot inducing translation. Alternatively the field can be pulsed, and induce a vibration into the micro-robot, causing stick-slip motion.
By using the four coils in varying configurations, the direction of the field gradient can be altered, providing two-dimensional translation.
Autonomous position is provided using computer vision to track the micro-robot. Motion tasks can be planned and executed using path-planning techniques from a computer.
The micro-robot is a permanent magnet, made of Neodymium-Iron-Boride. It is machined in a laser micro-machining system to dimensions 200x200x100 microns.
Control strategies will be implemented to ensure stability of manipulation, and will be implemented for task-based guided nanomanipulation.
Benefits
An externally controlled magnetic micro-robot provides the ability to place and control a micro-robot on any arbitrary surface. Approaches such as electrostatic actuation for micro-robots requires an appropriate surface with electrodes. Without these constraints, micro-robot motion on arbitrary surfaces can be realized.
Videos
Magnetic micro-robot moving on the back-side of a silicon wafer (2007) [Video]
Magnetic micro-robot pushing 116-micron polystyrene beads underwater (2007) [Video]
High-speed video of micro-robot in translation, 200 fps (2007) [Video]
Members
Steven Floyd,
Chytra Pawashe,
Brad Camburn,
Metin Sitti
