paper: 2014 HOT Tech Notes

Originally Posted by AdamHeard

This is all conjecture, but it looks like your chassis might have the ability to twist some vertically.

I've had a running theory for a while that a chassis such as that gets shoved into the carpet a bit odd under high defensive forces, contributing to the "locking up" affect.

Any thoughts?

If I may request clarification - when you say "twist some vertically", do you mean the chassis bows upwards down the center parallel with the drive wheels due to lack of frame stiffness, and through this bowing all wheel sets are in contact with the ground?

[AdamHeard]

Originally Posted by Andrew Lawrence

If I may request clarification - when you say "twist some vertically", do you mean the chassis bows upwards down the center parallel with the drive wheels due to lack of frame stiffness, and through this bowing all wheel sets are in contact with the ground?

Corners (with respect to the other corners) move up or down as the frame twist.

As for Andrew's request, we only have rigid frames

[MrRiedemanJACC]

We have a flexible chassis from this year, for Andrew's testing! But we used mechanums and therefore we weren't as concerned with frame stiffness. I don't know for sure that is was a good idea though. I think the hard part was that the loading would change on each wheel therefore changing how it drove. We would keep contact with all 4 wheels though. Also in our third event we changed from mechanum to traction and kop wheels (4wd) to try to play more defense for other newer teams. Worked well, but not sure I'd do 4wd drive again. Too much power with 8 motors in the drivetrain and we tripped the main breaker in our last two matches.

It is interesting in the drivetrain wars, how much it has changed the forces the robots receive. There is much more involved than picking motors and gear ratios, the frame is definitely part of it and maybe the Bees were onto something with the Omni wheels. Maybe the frame doesn't need to be as stiff and that weight can be used elsewhere with the omni directional drivetrains. Or you have to go in the other direction of stiffness. It's always a tradeoff.