Small, Fast, and under Control: Wireless Resonant Magnetic Micro-agents

Summary

Primary challenges in the building of untethered sub-millimeter sized robots include propulsion methods, power supply, and control. We present a novel type of microrobot termed Magmite that utilizes a new class of Wireless Resonant Magnetic Micro-actuator (WRMMa) that accomplishes all three tasks [1]. The device harvests magnetic energy from the environment and effectively transforms it into impact-driven mechanical force while being fully controllable. It can be powered and controlled‘ with oscillating fields in the kHz range and strengths as low as 2 mT, which is only roughly 50 times the average earth magnetic field. These microrobotic agents with dimensions less than 300 μm x 300 μm x 70 μm are capable of moving forward, backward and turning in place while reaching speeds in excess of 12.5 mm/s or 42 times the robot’s body length per second. The robots produce enough force to push 150 μm x 20 μm gold disks and can be visually servoed through a maze in a fully automated fashion. The prototype devices exhibit a degree of controllability and performance unmatched by other microrobots reported in the literature (see video material available online [2]). The robustness of our robots and systems leads to high experimental repeatability, which in turn enabled us to successfully compete in the RoboCup 2007 Nanogram Competition held in Atlanta, GA, USA.