Can wheels extend past the frame?

[GaryVoshol]

Originally Posted by toastnbacon

Thanks! We think we managed to fix the problem by simply moving the casters further inside the frame. Is it legal if they don't pass the frame Perimeter?

It's legal. Now read from some of the other posts here whether it's advisable or not.

[toastnbacon]

Yah, We thought about omni wheals, but we figured it would be to easy to push us around. I also proposed the ball casters to the team, but everyone thought the swivel casters would be fine. Could someone put the cons on here?

[Chris is me]

Omni wheels and casters should be equally easy to be pushed by. What resistance to pushing would casters give you?

[EricH]

More to the point, Chris, is "what resistance to normal motion do swivel casters give you?" I've heard the horror stories of teams using them, only to have their robot go a little crazy when a caster didn't act like it should have.

I've also seen teams use ball casters with some success; most teams opt for omni wheels of some form instead of casters as you can get a little bit more forward "oomph" from omnis.

Short and sweet: swivel casters won't give you any less resistance to being pushed around; in fact, they might be the ones doing the pushing. Ball casters are better about not pushing you around. Omnis give you a little bit more forward/aft push (though not much).

[Edoc'sil]

The big thing is a caster bot cant go straight to save its worthless life. The one place you cannot cut corners on in you bot is in your drivetrain. Fork over the cash for omnies. IMHO if it was legal a peg leg would be better then a caster.

[EricH]

Originally Posted by Edoc'sil

IMHO if it was legal a peg leg would be better then a caster.

I don't see any rules preventing peg legs. They just can't have metal feet. OK, and they might cost too much...

[Daniel_LaFleur]

Originally Posted by toastnbacon

Yah, We thought about omni wheals, but we figured it would be to easy to push us around. I also proposed the ball casters to the team, but everyone thought the swivel casters would be fine. Could someone put the cons on here?

Swivel casters give the worst of all scenarios. They give no traction (for pushing or resisting being pushed), and will (guaranteed) be facing in the wrong direction and cause your robot to not drive straight when starting to move. They do allow for fairly easy rotation of the robot. Cannot be powered. Swivel casters without suspension tend to get "shopping cart syndrome".

Ball casters also provide no traction,but do not interfere with the robot going in a straight line. They allow for much easier turning of the robot (easier than swivel casters). Cannot be powered.

Omnis provide traction (if powered) in one direction but not in the perpendicular direction. They allow for fairly easy rotation. They are expensive compared to casters.

Hope this helps.

[toastnbacon]

Thanks, this has all been a big help. Everyone else on my team still doesn't believe any of it, but I'm hoping when we drive around, they'll come to their senses.