With that in mind, I set about reverse engineering the
tracks and sprockets to make a set of 3D models available
to hobbyists. Most of these models are available on
www.teamrollingthunder.com website under "Solid
Keep in mind that tracks don’t necessarily give an
advantage over wheels in combat robotics, but they do look
cool! Plus, the Pololu tracks and sprockets should be tough
enough to survive most hits from smaller bots.
First, I created the standard 22T and 30T track sets
(Figures 5 and 6) with the standard 12T sprockets,
shoulder screws, washers, etc. You can use these to create
different arrangements like the four motor/six sprocket
arrangement in Figure 7. It should have plenty of power
for an Antweight.
Alternatively, one could use two of the Finger Tech
Silver Spark motors instead of the four smaller motors, or
two of the smaller motors in a weaponed bot. I don't think
anyone has built a tracked drum bot yet.
Next, I looked at making different sized sprockets and
even tracks using a 3D printer. Creating the model for a
six-tooth sprocket and a 40-tooth track (Figure 8) was easy
enough once I had worked out the basic geometry.
The sprocket works well, apart from having to drill out
the center hole as it was a little undersized. The track was
made from an experimental elastomer and while it appears
tough enough, it's a little too stiff to use with smaller
WIth the different sizes of sprockets and tracks
available, a whole new range of bot shapes becomes
possible. How about a cheese wedge shaped Fairyweight
that uses the 22T track, a standard 12T sprocket, and a 3D
printed six-tooth sprocket? If you can imagine it, then it can
probably be made.
The 6T sprocket and other 3D printed parts are
available from www.shapeways.com (search for kitbots)
and the standard parts from www.pololu.com. SV
SERVO 03.2014 39
FIGURE 6. 30T CAD models.
FIGURE 7. Four motor 30T track assembly.
FIGURE 8. 3D printed parts.