I have attempted to calculate the necessary gearing ratio for a mecanum drivetrain. The drivetrain will have 1 CIM per wheel (and no other wheels), and use 8-inch Andymark mecanums.
I calculated the gear ratio so as to be traction-limited under the following assumptions:
- 150 pounds max robot weight
- 0.7 max CoF for the wheels (reported by Andymark)
- 40 amps max continuous current per motor
I came up with a desired ratio of about 16.25:1. This results in a theoretical free speed of 10 ft/s.
Last year's robot used a kit frame. This had about an 8:1 gear ratio. Since this computes about double the required gear ratio for (theoretically) slicker wheels, I am skeptical of my results.
Does this seem correct?