Converting to Mechanum....

[JamesCH95]

You might have to modify the wheel brackets to accept mecanum wheels, on our prototype chassis in 2010 we had to slice open the wheel stalks to fit 8" AM mecanum wheels.

[Ether]

Originally Posted by JamesCH95

You might have to modify the wheel brackets to accept mecanum wheels, on our prototype chassis in 2010 we had to slice open the wheel stalks to fit 8" AM mecanum wheels.

Yes, and that exacerbates the cantilever/stiffness concern.

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[Gdeaver]

Good, potentially another mecanum wheeled robot to push and smash around. Our team so loves to torment them.

[Ether]

Originally Posted by Gdeaver

Good, potentially another mecanum wheeled robot to push and smash around. Our team so loves to torment them.

They will have the opportunity to learn a lot of engineering and physics that other students on pushing and smashing and tormenting teams miss out on.

If next year's game isn't about pushing and smashing and tormenting they may even beat you.


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[ttldomination]

Originally Posted by Gdeaver

Good, potentially another mecanum wheeled robot to push and smash around. Our team so loves to torment them.

Mecanum wheeled bots are easy to push around, but with the right mind set, mecanum wheeled robots can be huge pains when playing defense, and just out right speed demons when playing offense.

Originally Posted by Ether

If next year's game isn't about pushing and smashing and tormenting they may even beat you.

I for one believe that the 6/8 WD is still the way to go. IMO, the teams that went with 8WD this year (254, 1114, 1771 to name a few) were able to move around much easier than most mecanum wheeled bots. But of course those teams do a thousand things right in order to get their DT in perfect condition.

[,4lex S.]

Want a simple test frame, and don't want to take apart your robot too much? Use 3/4" ply and mount your wheels via pieces of channel into cut outs. You can just screw down the toughboxes with the standard mounting hardware. The bonus of plywood is that it will help keep even weight distribution on all your wheels because of its flexibility.

I think everybody else covered the tech requirements, but make sure you have someone willing to program it, or it will be a pain to deal with. I am sure you won't be convinced until you have built it yourself (because I was the same way ), but a 6/8WD done after some research on CD and careful design is the best drive train for FRC (you can always make modifications to make it work better for the game at hand).

[Ether]

Originally Posted by ,4lex S.

make sure you have someone willing to program it, or it will be a pain to deal with.

programming mecanum is not difficult.

2-axis double-joystick "tank drive with spin" and 3-axis single-joystick algorithms are available here:

http://www.chiefdelphi.com/media/papers/2390

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[,4lex S.]

Ether,

I was aware of your whitepaper, and I intend to make my way through at some point. The real challenge I see here relates to my experience with my own team, without a skilled programming mentor. You must have a passionate and supported programming squad to attempt anything, let alone something that is outside of the basic drive code, and I do not know the situation of the team at hand. In 2008 I (as a mechanical student) asked my team to work with a holonomic platform, and it did not progress as harmoniously as we would have liked due to the limitations on our programming knowledge. The key is that this kind of work is more multidisciplinary than some other ways of attacking the same problem, so the potential programming hiccups have to be weighted against mechanical advantages (if issues are likely).

The only reason I say there are likely to be programming issues, is because I have been there. Doing this in the off season is probably a really good choice, because the wrinkles will be out by the time the season rolls around.