Table Top Games - Line Following

[tatwood]

Table top games represent the most advanced forms of line following competition developed by the pioneering roboticists at the Chibots club. This category involves tape-marked end zones that a robot must travel between.

I'd like to open the discussion with the following question, but any relevant question is fair game for any who wish to join this thread. What is the object of this kind of competition--what are the robots seeking to do? And are there any sure-fire best platforms/sensor combos to start with? Thanking in advance any who comment--

Tom Atwood
toma@botmag.com

[wrighthobbies]

The tabletop competition is detailed on the Chibots web site - http://www.chibots.org/contests/rules/tabletop.html

It is a race against the clock with additional scoring. The goal is to move from one end of the table to the other end and back as quickly as possible without falling off the table or breaking the rules. It is simple in it's most basic form but can get to be tricky considering the consequences of a mis-step (ask John Kjellman what happens when a sensor works in one direction only!).

Just about any platform can be used - Lego, Vex, scratch-built. I built several using Tamiya parts, starting with a single motor design, then changed to a dual motor setup.

http://www.wrighthobbies.net/video/ttbot_testSD.wmv

I also built a 4wd version.

http://www.wrighthobbies.net/video/tablebot4x4.wmv

The additional motors driving all 4 wheels improved acceleration and deceleration as you would expect.

I took it a step further and built a 6x6 bot. Having 6 motors driving 6 wheels made for some serious acceleration/deceleration.

http://www.wrighthobbies.net/video/hexabot-sm.wmv


There are several considerations to keep in mind for optimal performance:

Mass takes energy and time to get moving and to stop. Reducing mass will greatly improve performance, especially in this type of competition.
Traction is required to accelerate and decelerate the robot. High traction tires and high torque motors will make a big difference in performance.
Sensors are a good idea but aren't actually needed for this competition. It's possible to do it purely with timing, though it is hard to tune the bot on contest day.