Monday, July 27, 2009

Waterloo Robot Race 2009

Waterloo Robot Race 2009

Snowtires went to the races, and competed in the Waterloo Robot Race for 2009, competing against 10 other robots, qualifying for the final race, and finally placing second overall. This competition marks the culmination of this project (for now). I was ecstatically pleased with the performance of Snowtires, and happy to note that some of the other UBC robots used elements of the Snowtires guidance code for their own vision systems.

The Waterloo Robot Race is a trio of challenges. The first is a drag race, a flat-out speed competition down a cone-lined track. The second is a round of static judging for aesthetic and technical appeal. The third round is the circuit race: a cone-lined figure-8 track with a moving purple obstacle cone at the intersection. There are also two stop signs and a traffic signal. The robots face penalties if they do not stop for three seconds at the signs and for the duration of the red light at the signal. Additional penalties are levelled when robots take the wrong path or hit the orange cones.

The UBC-CERM3 Thunderbird robotics team entries:


From left to right: Snowfury MkIII, Johnny5, Snowtires, Big Dave, Quartz, and Oscar.
  • Snowfury MkIII was the original Team Thunderbird 1/10th scale racer, and is shown here in its third incarnation as a vision-guided robot. It uses the snowtires vision code in an underdamped, aggressive configuration. The basic platform is a Tamiya Hummer with an ASUS eeePC 701 computer onboard. Snowfury was constructed and operated by Marcel Veronesi, with assistance from Tim Lee. Snowfury achieved the shortest time in its heat and placed fourth overall in the competition.
  • Johnny5 is another vision-based robot, which runs a more conservative configuration than Snowfury. Johnny5's creator Tom Huryn pioneered the rear-mounted camera configuration - the further back the camera is, the better peripheral vision the robot has, improving its ability to avoid objects at close ranges. The underlying platform is a Traxxas Rustler, with an eeePC for the brains. Johnny5 placed 5th in the competition.
  • Snowtires is my machine, seen here with its new bodyshell. We integrated infrared rangefinders for close-range collision avoidance, but in the bright sunlight of race day they were of little use except at point-blank ranges. Snowtires placed second in the competition.
  • Big Dave is our fourth vision machine, constructed and operated by Tim Lee. It is configured similarly to Snowtires, with an up-front camera and pure vision guidance.
  • Quartz is the team flagship, constructed and operated by Ash McKay. Equipped with a laser rangefinder, it has an accurate and detailed 2D view of the world. It uses a vision system to detect stop signs and traffic signals. The rangefinder can detect the purple obstacle cone, and so Quartz is distinguished and the only robot in the entire competition with a full suite of features, capable of handling all of the competition challenges. Quartz placed third in the competition, and would have placed first if the penalties for ignoring the traffic signs and lights were of any significance. It wowed the crowd right out of the starting gate for recovering from a guidance error by backing up and correcting its course.
  • Oscar is the maverick robot, eschewing vision guidance for sonar-modulated odometry guidance. Oscar had a map of the course, and verified its position using sonar readings. However, sonar units have trouble in outdoor areas, particularly under the high winds that we experienced on race day.
Race Day!

Race day opened with an electrical storm. The competition
rules said rain or shine, so we got to work putting the waterproofing
on our robots - plastic bags covering the gaps in their bodyshells.
Fortunately the rain cleared up by the time we got there.


Here's Snowtires in race regalia, during a practice run on the
course. The course was largely dry with puddles by the
time we were practicing.

The crossroads, compete with stop sign and purple cone (with its crane).

video
A test run with Snowtires (I don't have any race footage as I
was poised over the panic button in case the robot made
an error: I'll post some of my colleague's footage when
I get it. Note how Snowtires avoids puddles when it sees
the reflection of a cone in them.

video
Here's the drag race: my heat against the Windsor U. robot.
The Windsor robot was a torpedo: it went on to win the competition
due to its mixture of vision guidance and raw power. A little
frightening recovery at the end there, but awesome to behold.

video
My robot is considerably more conservative. So much so that
this video is of the same drag race, just, you'know... later.

video
In the second round, I was up against Quartz. My starting timer
didn't engage, so I started three seconds before I should have,
and took a 3 second penalty. It didn't matter anyway as Quartz
passed Snowtires on the straightaway to take the victory.

video
This is Windsor's Team Invincible running the circuit race.
Their robot has impressive speed, and really pulled out all the
stops for the main race. As they pass the intersection you can
see Johnny5 crossing the finish line as part of the previous heat.

Here's Quartz mere feet from the finish line. Due to a battery issue,
Quartz had a slow second half of the race, but placed third anyway
due to making only a single error in three whole laps.

video
And here's Snowfury doing its wild weasel routine. The vision
guidance is underdamped, so the robot "bounces" off the sides of
the course, as it usually can only see one side at a time. It had the
second fastest lap time after Windsor, and lapped Snowtires, but
incurred more penalties while doing so. Definitely the
"people's choice" and really entertaining to watch.

Windsor took first, and UBC took places 2-6. None of the other robots fielded were able to qualify to race, in some cases only due to issues with outdoor operation. There were several impressive contenders, but in the end it was a Windsor/UBC field. We're very pleased with the results, and we'll be passing a good legacy on to future Thunderbird robotics club members.

A big thanks goes out to our sponsors, and to everyone who made this possible. To our team leader, Dr. John Meech, and all the robotics club members this has been fantastic, thanks for one wild ride.

-t