IEEE Spectrum October, 2016 - 42

I raced over to rescue it, and as we heaved the rusty
thing into her car I remembered how Connell and I had
promised Coach Teevens a working device. I called Connell, who was then teaching at an outdoor education
company in Colombia, and we decided to spend the summer working full time on the project. We launched a Kickstarter campaign to raise the modest sum of $5,000, and
a handful of generous alumni matched that amount. If
we didn't have a working prototype by the summer's end,
we agreed, we'd put the project to rest once and for all.
Connell came back to campus, and we got to work.
Though we'd both studied mechanical engineering, we
didn't need EE degrees to recognize that a lead-acid car
battery was a poor fit for our project. We needed something lightweight with enough juice to move a humansize dummy quickly around the field. For inspiration, we
looked to the U.S. TV show "BattleBots," where contestants build powerful yet compact robots. We tried many
different batteries and setups, with plenty of failures:
More than once we left the football field with smoking
wreckage when a drive system burned through wires or
damaged the batteries. Eventually, though, we found
a lithium battery that suited our robot.
Our biggest goal that summer was to improve the
ball drive. We tried many different air-filled balls, and
we turned out dozens of intricate components on the
engineering school's 3D printer as we tried to get better
traction between the drivetrain wheels and the ball. We
eventually developed a housing mechanism where the
ball was held in place with sprung casters, which kept
it tensioned against the drive wheels. But those casters
gave the dummy less clearance, limiting it to hard surfaces or smooth turf.
By August, we had a robot that we could drive slowly
straight down the field, but it still had lousy traction on
grass and tended to drift rather than turn sharply. The
pressure was on: Dartmouth's football training camp
was only weeks away, and we were also running out of
budget. We were working around the clock and living
on ramen noodles, but we still didn't have a prototype
that could meet Coach Teevens's expectations.
CONCUSSIONS SUSTAINED
BY NFL PLAYERS

It was time for something radical. So we gave up on the idea of
having a perfectly omnidirectional robot and abandoned the ball
drive, deciding to try wheels instead. Connell spent one long night
with a computer-aided-design program to make a new model, and
then we hit the machine shop. We took apart old tackling dummies
to salvage their foam and roughed out a shape, then hastily installed
an electric motor and the electronics. When we had everything
put together, at the end of a late-night work session in mid-August,
we took the robot for a spin around the deserted lab. We found to
our surprise that it moved well-really well.
We loaded the dummy into the back of a truck, and during our
drive to the football field we crossed paths with a Dartmouth
rugby player who volunteered to help out with the first test. While
Connell remotely steered the speedy robot in loops and zigzags
around the field, our expert tackler repeatedly ran after the bot
and took it down. We were delighted to see it pop up after each
hit, ready for more action.
Later that day, our rugby friend tweeted a 30-second video
of the test run, and something amazing happened: It went viral.
Within 24 hours the video had been viewed 1 million times, and
coaches and players were clamoring to buy the bot. When our
heads stopped spinning, we realized that our robot could be much
more than a school project.

on opening day of Dartmouth's 2015 football camp, two prototype MVPs joined the burly players in their first tackling drill. Connell and I watched as huge defensive linemen took turns smashing
into our padded robots, wondering if the electronics would hold
up to this abuse. We had cause for concern: About 3 minutes into
the drill, an MVP popped up from a hit with one wheel running
continuously at full speed, making the robot spin around in tight
circles. I hustled it off the field, and when we pulled it apart we
discovered that a battery lead had been jarred loose and, astoundingly, connected itself directly to a motor lead, entirely bypassing
the electronics platform controlling the voltage. After that incident
we installed robust fuses, connectors, and fail-safes to prevent
glitches that could cause robots to go rogue.
The rest of the 2015 season came and went. Every day of practice the Dartmouth football team put the MVPs through their
paces, and every night our team replaced bolts and repaired
broken parts. Our final prototype weighed about 70 kilograms

CONCUSSIONS SUSTAINED BY NFL PLAYERS
IN 2015 DURING REGULAR SEASON GAMES

TOTAL NUMBER OF AMERICAN FOOTBALL PLAYERS
AT YOUTH, HIGH SCHOOL, AND COLLEGIATE LEVELS

300
250

Estimated number of
players who sustain at least
one concussion annually

271

261
229

200

206

YOUTH: 3 MILLION

150

HIGH SCHOOL:
1.1 MILLION

CAUSED BY PL AY ERON-PL AY ER IMPACT: 140

100

COLLEGE:
100,000

50
0

2012

2013

2014

2015

TOTA L SUSTA INED: 182

99,000

79,6 40

3,905

Sources: 2015 Injur y Data, NFL, 2016 (left and center); "Incidence of Concussion During Practice and Games in Youth, High School, and Collegiate American Football Players," JAMA Pediatrics, 2015 (right)

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Table of Contents for the Digital Edition of IEEE Spectrum October, 2016