Ask the Builders: Team Run Amok
What does it take to win Robotica? Champion Mark Joerger, builder of Run Amok has answered your emailed questions.
See his answers below.
Q: Congrats! Great job!
Did you name your robot after the Daffy Duck cartoon?
In my mind the phrase "run amok" has always been associated
with "robot." Whenever a robot appeared in a 1950s science
fiction movie (I'm a big fan) you could bet that it was there
to do one thing: run amok and try to kill its creator. Run
Amok hasn't exactly tried to kill me (yet), but I do have a
Q: I'm 13 and I'm
building a robot (really- I'm not just saying this). Where do
you think I should get a motor — at the local dump? Would a
lawnmower motor work?
Your robot's motor will have to put up with a lot of stress,
and scrimping by using a motor from the local dump is not
recommended. I would suggest sticking with proven components
for your first robot. You'll have plenty of opportunity to
experiment in future designs.
Check the web sites of some of the successful robots of the
general type you'd like to build to see what motors they use.
Most builders will be happy to share this information with
you. Motors from electric wheelchairs are currently a popular
choice for heavy combat robots and they are very easy to work
Q: What was the most
significant part of Run Amok's design that gave it the edge
over the other competitors?
Colin Chapman was one of the great automotive designers of the
20th century. He had a one-word phrase that he liked to use to
sum up his design philosophy: "Simplificate". Run Amok has a
very simple yet elegant design. Thanks, Colin — for the
More specifically, I think there were two key design
elements that lead to our success: the automotive-style
steering and lots of ground clearance.
With only seven weeks available to build and test the
robot, I knew I wasn't going to have a lot of time to practice
operating skills. The automotive steering matched well with my
R/C driving experience and felt very natural to me from the
start. It is also much easier to make smooth turns around a
track with steerable front wheels. This may be why no
bulldozer has ever won the Indianapolis 500.
Run Amok's very large ground clearance (more than 4 inches)
kept us from hanging up on the speed bumps in the Maze, and
allowed us to fight our way free from debris in the Gauntlet.
Run Amok was not the best robot at any single challenge at
Robotica, but we were capable of completing all of
them. We also had a great big double-scoop of luck!
Q: It was nice to see you
and your son win. Did the motor look bad after everything was
done? What kind of motor was it? I thought that it was great
that you beat all the high tech robots...
My son and I had a really great time at Robotica
I'd like to recommend robot building as a wonderful father/son
(or father/daughter or mother/son or mother/daughter)
The motor not only looked bad, it smelled bad! Run Amok is
powered by a single Bosch GPA 750 motor running at 24 volts
with a peak power output of about one and a half horsepower.
At the end of the Gauntlet run in the finals, there was smoke
pouring from the motor and it smelled like a burning pencil.
All the effort of pushing at low speed and high loads had
seriously heat damaged the coating on the wires in the
armature. We had a spare, but after allowing it to cool down
and giving it a load test, I decided that the damaged motor
had a few more minutes of life left in it. We left it in for
the Fight to the Finish rather than risk a mishap while
Q: How did you come up
with the idea to convert a gas engine riding lawnmower into an
electricity- powered robot?
For the sake of simplicity and economy, I wanted to use a
single motor to power Run Amok. In order to get good traction
and a tight turning radius from a single-motor design, I
needed some type of differential assembly for the drive axle.
I went to a scrap yard for old lawn equipment looking for a
chain-driven rear axle assembly. I found a 29-year-old riding
lawn mower that had a perfect axle assembly. As I stood there
looking at it, inspiration struck.
Here was a well proven chassis that had spent decades
hauling somebody around a yard. It had perfectly workable
steering and axle mounting systems were already attached.
Certainly the heavy gauge-stamped steel would put up with the
abuse of robotic combat, and there was plenty of room to mount
the required batteries and electronic components once I
removed the blade assembly, transmission, and engine. Even the
wheels and tires would work. It was pure serendipity.
Q: How did you come up
with your strategy in the final battle?
One of the classic problems in game theory is called "the
three-way duel." The problem involves three marksmen — two
very good, and a third that is only so-so. It turns out that
the so-so marksman has a very good chance of winning the
shoot-out if he just bides his time and waits for the right
moment to make his move. Run Amok was the so-so robot of the
three in the final battle and, once it became apparent that I
couldn't break into or influence the titanic struggle between
JuggerBot and Ram Force, I retreated to wait for my "right
Q: Congrats on a really
fantastic victory. What are you going to do now? Are you going
to build another robot?
Almost as soon as we returned from the Robotica
competition, my son pointed out that he didn't think that it
was fair that I got to have all the fun driving Run Amok. Fair
is fair, but I really didn't want to turn a 10-year-old boy
loose with 170 lbs. of high-powered steel and aluminum.
Inspired by Jason Dante Bardis' "Mini Inferno" entry in
Robotica, I set out to build "Mini Run Amok" for my
boy: an operating 40% scale model of the full size beast. You
can see some photos of "Mini" on my web
Other projects? Stay tuned.
Picture(s): Ed Carreon/DCI
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