IEEE Robotics & Automation Magazine - March 2014 - 8

COMPETITIONS

Robust and Reliable Microtechnology
Research and Education Through
the Mobile Microrobotics Challenge
By Dan O. Popa

nspired by the success of Robocup
[1], the U.S. National Institute of
Standards and Technology (NIST)
[2] proposed a robot competition at
the microscale-the Mobile Microrobotics Challenge (MMC). Microrobots for this competition utilize
microelectromechanical system technolog y and are actuated using
advanced control systems.
The first MMC competition was held
in 2007 with the name Robocup Nanogram [3]. The MMC has been held at the
IEEE International Conference on
Robotics and Automation (ICRA) every
year since 2010 and involves microrobots
that must fit within a 500-nm- diameter
sphere [4]. In a controlled setup under a
micros cop e,
microrobots
Teams must qualify
race along a
distance of 2
for the challenge
mm, push micby sending a
roparts, or slalom around
proposal and also
obstacles.
demonstrating basic
In 2013, the
NIST delegated
maneuverability of
responsibility
their robots ahead of
for the organization of the
the competition.
MMC to the
IEEE Robotics
and Automation Society (RAS), where
the IEEE-sponsored challenge was led
by a committee of representatives from
the RAS Micro-Nano Robotics Technical Committee. In 2014, the MMC will
Digital Object Identifier 10.1109/MRA.2013.2297597
Date of publication: 10 March 2014

IEEE ROBOTICS & AUTOMATION MAGAZINE

be held in Hong Kong at ICRA 2014 [6].
Teams must qualify for the challenge by
sending a proposal and also demonstrating basic maneuverability of their robots
ahead of the competition.
Microrobot Challenge 2007-2013
In the first few years of the MMC, NIST
provided competitors with the arenas,
as well as with the driving electronics.
Early competitions took place with electrostatic actuation under a microscope
for three categories of drills:
● 2-mm Dash: The microrobots race in
a straight line across the playing field
in a test of raw speed.
● Slalom Drill: The microrobots dart
around obstacles to test their agility
and controllability.
● Ball-Handling Drill: The microrobots retrieve a set of balls and dribble
them across the goal line.
Microactuation approaches varied
from [7], which discusses an electrostatic microrobot of dimensions 250 #
60 nm # 10 nm powered through a
capacitive coupling with the underlying
substrate, to the work [8], demonstrating a 250 n m # 130 n m # 100 n m
magnetic microrobot that can operate
under the excitation of an external
magnetic field. One of the more successful designs was a resonant magnetic
actuator composed of two paramagnetic bodies, a spring system and a
metal frame. It can move forward,
backward, and turn in place with a forward speed up to 12.5 mm/s [9].
In the early years, the MMC was
clearly dominated by European teams,
for instance, in 2010, ETH Zurich was

MARCH 2014

the winner of the microassembly event
with their Octomag magnetic drive
[10], and the French CNRS-sponsored
team was the winner of the 2-mm dash
event with a hybrid magnetic/piezoelectric microrobot [11].
In later years, teams were invited to
bring the microactuation technology
of their choice, as long as the drive system, the arenas, and the microrobots
abide by strict dimensional guidelines
and can fit under the competition
microscope. As the 2-mm dash and
microassembly with pegs matured, and
more teams successfully completed
both events, new challenges were put
forth, starting with the 2011 competition (Figure 1):
● the figure-eight mobility challenge,
where the goal was to complete a
closed path connecting four narrow
gates in the shortest possible time
● a microassembly challenge, where
the goal is to tightly assemble triangles into a narrow conduit by pushing them with the microrobot.
In many instances, the microrobots
themselves were either passive magnetic structures or they could be micromachined to resonate at various input
frequencies. And, in recent years, several North American teams [Carnegie
Mellon University (CMU), University
of Hawaii, Stevens Institute of Technology, and the University of Texas (UT)
Arlington] have also been strong contenders. U.S. teams, in particular, have
been boosted through a National Science Foundation (NSF)-sponsored
grant that funded student travel to the
competition venues since 2011 (grant

Table of Contents for the Digital Edition of IEEE Robotics & Automation Magazine - March 2014