inches high, or so. They must weigh
less than 50 pounds and fit within a
four foot cube for the duration of the
race. Some crawl away from the
starting point at a speed slower than
a stroll in the park and others race
away at breakneck speeds. I’ve seen
contestants running behind their
speeding Robo-Magellan robot,
barely able to keep up, with the
safety tether in their hand ready for
an emergency stop.
FIGURE 1. Robo-Magellan contestant.
Figure 1 (courtesy of SRS) shows
a contestant holding the safety tether
in the October 2006 competition.
Wireless safety switches are admissible, but most contestants use a wired
tether. In the early years, we had a bit
of trouble with the GPS satellites
being shadowed from the robots by a
high wall or even the Space Needle,
but this made the contest a bit more
challenging when the competitors
transferred navigation to odometry
and compass navigation.
Newer and more sensitive
receivers solved a lot of the GPS
reception problems in later years. I
never saw an entry that wasn’t first
class, though some did manage to
get lost or stuck behind obstacles.
As stated in the rules set up by
the SRS, “Robo-Magellan is a robotics
competition emphasizing autonomous
navigation and obstacle avoidance
over varied, outdoor terrain. Robots
have three opportunities to navigate
from a starting point to an ending
point and are scored on the time
required to complete the course with
opportunities to lower the score based
on contacting intermediate points.”
The ‘chicken switch’ tether I
mentioned previously is allowed to
disable the robot when it is deemed
unable to continue or will run into a
person or obstacle, but all control is
autonomous and navigation is by GPS
coordinates (no differential GPS to
enhance the accuracy), visual cameras
(to avoid obstacles and locate the 18”
orange traffic cones), and on-board
compasses.
The contest is held outdoors (for
best GPS reception) and is usually on
sidewalks, grass, and has some unique
ramps and turns. The contests at the
Seattle Center have always attracted
a crowd of people who excitedly
follow the robots around the course.
Sometimes a person with an orange
jacket or hat will confuse the robot
so that it deviates from the course
because it thinks it has seen the
orange cone.
It’s always fun to explain to the
crowd just how intelligent the robots
are and why they do certain things on
the course, (which can be longer than
1,000 feet). Scoring is based on time,
but points are also given for locating
and touching all waypoint cones, so
slower robots have frequently bested
the speedier machines. Contestants
are given the course coordinates just
before the contest and are allowed to
traverse the course themselves before
their robot makes its run (a maximum
of 15 minutes is allowed for each
run). Other groups have used desert
courses, woods, and strictly urban
courses with only concrete and
asphalt. To make the course more
interesting, overhead trees, inclines,
curbs, garbage cans, park benches,
shrubs, and even streams have been
included. Target cones are hidden
from view at the starting points and
at the waypoints. Go to www.robot
hon.org/robothon/robo-magellan
for more detailed rules and
information.
IEEE Micromouse
Competitions
Running a maze with a robot has
always been a draw and people have
built robots to solve simple mazes
since before the microcomputer age.
In 1977, IEEE Spectrum magazine
announced a ‘micromouse’ contest
that would be held in New York in
1979. That gave time for the 6,000
initial entrants to design, build, and
fine-tune their creations. Fifteen
finalists were selected for the
competition to be run in a 10’ by 10’
maze. The winner of this first contest
was a simple, high-speed wall-follower
that used no sort of ‘intelligence’ to
seek its goal. These types of mice
simply turn a certain direction when
detectors locate the absence of a wall
and continue turning in that same
direction for the same reason,
many times until they eventually
(accidentally!) reach the goal. Rules
were changed to eliminate these
types of entries.
As the contest series gained
popularity in the early 80s and groups
around the world became interested
in participating, the rules became
more defined. ‘Mice’ appeared in all
sorts of forms. David Buckley of the
UK came up with Quester in 1981 —
a large 8” by 7-1/2” by 5-1/2’
micromouse that used a vision system
to detect the maze walls and bump
sensors when those sensors failed.
(See Figure 2).
Buckley gained a bit of fame
when Quester was featured in one
of the earliest non-industrial robot
magazines, Robotics Age. The First
World Micromouse Competition was
held in Tsukuba, Japan in 1985 and
the top six winners were all locals.
After a few sporadic contests in the
US with low attendance and few
FIGURE 2. Quester from the UK.
SERVO 11.2008 79
