Microscopic Off-Roading
Operating on a scale far smaller than human eyes can even see, a new class of microrobot looks poised to reshape the way we think about how robots are used in medicine. The “microscale magnetic tumbling robot,” or microTUM, could be revolutionary because of the way it moves. A research team from Purdue University published a summary of its development of the bot in Micromachines last month.
Described in detail in the paper is the microTUM’s unorthodox means of locomotion. The tiny machine uses a continuously rotating magnetic field to power itself forward. Magnetism quite literally causes the bot to tumble over itself in a somewhat erratic but constantly forward-moving manner. This allows the microTUM to negotiate tricky surfaces—wet or dry, flat or inclined, smooth or sticky—in a way that bots relying on an alternating magnetic field cannot. Purdue graduate student Chenghao Bi emphasized that the continuously rotating field helps the microTUM “take advantage of the constant adhesion and frictional forces between itself and the surface below it to climb steep inclined terrains.” Clearly, these little devices are much better equipped to take their activities off-road than their predecessors were.
Why Climbing Matters
The most obvious applications for the microTUM are in the biomedical field. The robot’s physical shape calls to mind an hourglass, wide at the ends and narrow toward the center. Both ends are magnetized, while the middle is not. That design could allow the bots to carry a payload. At some point in the not-so-distant future, such cargo might easily be a drug that needs to be delivered to a highly localized area inside a patient’s body. Robots currently do not play a major role in that process. That’s why the ability of the devices to handle unpredictable terrain is such a significant development. Maria Guix, a postdoctoral research associate working on the project, contextualized this capability. “The ability to climb is important because surfaces in the human body are complex,” she explained. “It’s bumpy; it’s sticky.” A robot delivering a drug that targets and kills cancer cells can’t afford to be derailed.
How Soon Could We See the microTUM in Operating Rooms?
While the microTUM’s continuously magnetized propulsion makes it uniquely promising from a biomedical standpoint, there are significant kinks to be worked out before it might reach widespread use. The surfaces the robot might encounter inside the human body are so diverse and unpredictable that more modeling is necessary to better gauge how it will move in various situations. Its midsection will also have to be redesigned to handle specific types of payloads. For that reason, specialized iterations of the microrobot are likely to appear in the future to help the device handle specific biomedical roles. Still, this version is a true pioneer in terms of its locomotive versatility. The day that this particular piece of biomedical engineering saves a life may not be too far off.
Read more about mini-robots with RoboBee: The Latest Buzz in Micro Robotics.