pic: LEGO Coaxial Swerve Module

[philso]

This is cool and so elegantly compact. The one Steve made is cool too.

Originally Posted by bstew

The reason the 12 tooth gear is on a 3m axle is because if I extend it across between the liftarms, it rubs on the tire. The way it is now is the best solution I could come up with.

The 12-tooth gear may end up adequately constrained (for the forces involved) by the gear below it and the one above it, laying horizontally. Those 3x5 L-shaped liftarms are pretty stiff so the gears might not skip.

Did you want to use the chain or 40-tooth gears for turning the modules, for powering the drive wheels or for both? Have you considered using long axles and the knob-gears Calvin referred to? The axles aren't that great at resisting torque but then you get gear lash with a large number of gears.

For "Smart Move", one of the local whizz kids and his partner attempted to build a second robot with swerve/crab drive for the Championship in February, after the Qualfier in November. I think their school ran out of parts and they could not manage to get the software going (no mentors on his FLL team). They did end up winning Third Place in Robot Performance using a robot they started building less than 24 hours before the Championship.