Stronghold Drivetrain Review

[BoilerMentor]

I never thought I'd see the day that we'd use a treaded drive, but this was the year.

Basic:
Waterjetted, folded aluminum drive pods with custom pulley layout
AM Rhino Belts
Rhino pulleys (replaced due to cracking during build season)
Custom single reduction, single speed gearbox ~6:1
2 cims and 1 mini cim per side
static belt tensioner per side

Advanced:
3 pulleys at "ground level" center ~1/8" lower
2 pulleys at "frame level"
Bevel at each end to allow crossing in either direction
~26" Width (outside to outside)
~30" length (outside to outside at frame level pulleys)
~20" of floor contact per side
Belt tension was entirely subjective, but we never threw a belt

Control:
3 Talon SRX motor controllers per side
split stick arcade drive scheme on a game pad

Maintenance:
gearboxes regreased at each competition
pulleys inspected for cracking (none observed through competition season)
belt tension verified
belts never replaced

Observations:
Despite my aversion to treaded drives, I'm very pleased with the behavior and performance of our drive train this season. If the game required it, I think we'd certainly dust this one off and use it again.

Power availability is going to drive our design and gearing decisions in the future. The brown out situation lost us some matches we really should have won, or at a minimum cost us some time because of added difficulty in executing crossings.

If we were approaching this problem again, I firmly believe the choice to neglect to add suspension is the right one. Yes, it would have reduced the wear and tear on the robot from hard impacts, but from observing behavior of other treaded drives that incorporate suspension it would appear that the issue of appropriate spring rates and damping aren't trivial and can lead to really problematic behavior through defense crossings.