pic: Vex Swerve v3

[JVN]

Originally Posted by Ben Piecuch

John,
I see that you used quite a few gears to increase the turning speed of the crab modules. I'm assuming that directly driving the modules was too slow? And, when you increased the speed (thereby decreasing the torque) you found that you required a 2nd motor to handle the job?

Ben,
The module steering is done with Vex servos. (This allows for a "no-programming" swerve drive.) These servos have LESS rotation than I wanted my wheels to have, so I geared them up (not to increase the speed, but to increase the range of motion). I used the large 84 tooth gears simply because it created an elegant package with a minimum of gearing. (The less reductions used to transmit the steering torque, the less slop your modules will have; using chain isn't an option, because the chain stretched too much.) Once I used the basic 84:60, I realized that was too much increase, so I did some preliminary slowing. (I broke the rule of never slowing something down, only to speed it up again).

The resulting steering ratio was:
60:36, then 84:60.

Originally Posted by Ben Piecuch

Can we expect these "custom crab module plates" to be available anytime soon? Great job as usual, John!

BEN

I think there may be a "swerve" kit available shortly.
Believe it or not, I don't just sit around playing with robots, this is a new product. I only hope there is some interest.

JV