31-01-2011 23:49

rutzman

Re: pic: Team 3547 'Our Ocotcanum'

I like.
I drew up an Octocanum over the summer and now that I've seen a few teams try it I would like to pick their brains about it...
1)Is that an 8" mecanum with a 4" plaction wheel? Why did you choose that particular combination?
2)What is the final gear reduction running to the mecanum?
3)Have you had any issues with side loads on the plaction wheel, and if so, how have you dealt with them?

01-02-2011 10:02

Jeffy

Re: pic: Team 3547 'Our Ocotcanum'

The wheel pod appears to be mounted on a fulcrum (as opposed to a linear slide), but the pneumatic cylinder does not. How does this function? Everytime I have used an acuator of sorts, the base of the actuator has needed a fulcrum.
Does it rely on the flex of that aluminium bar?

01-02-2011 13:37

Madman503

Re: pic: Team 3547 'Our Ocotcanum'

It’s a solution our lead design mentor came up with. It’s in that aluminum block the cylinder connects to. Sorry for being vague I’m not sure how much I’m allowed to give away.

And to rutzman, we chose that as a way to both make the length of the module shorter and naturally geared 2:1 and whatever we choose for our sprockets on the wheel. As far as side loads in the traction wheels are concerned we haven’t had a real problem they were made very sturdy and shouldn’t be a large issue. All the ratios, other than the obvious 2:1 from the wheels, are classified. Sorry.

FYI. im mentoring on 3547, i used to mentor for frog force (503)

02-02-2011 14:21

KrazyCarl92

Re: pic: Team 3547 'Our Ocotcanum'

Very cool! Hopefully we get to see this at competition!

Out of interest, what specific design criteria led you to choose this drive train instead of more traditional drive trains, like 6WD, 8WD, omni, mecanum, swerve, etc.?

03-02-2011 11:16

Madman503

Re: pic: Team 3547 'Our Ocotcanum'

Well we liked the maneuverability of mecanum drives and also like the idea of being defensive. While a 6 wheel drive can be plenty maneuverable and fast...unless you use super shifters, you end up just choosing speed or pushing power. And the idea of us using swerve in our rookie year seemed daunting. This drive train however allows us the choice to be extremely fast and maneuverable, at the same time as giving us the ability to push and be defensive. As it often happens with really good teams/robots, when they are a threat, you have strategies against them for defense, often pushing/pinning. so we wanted to be able to deal with those kinds of strategies. I was thinking of building a drive similar to this when I saw 217 last year, and when I got back from kickoff this year, another mentor on my rookie team was thinking the same thing so we ran with it and it works great. Once we tweak the gear ratios a little to optimize the robots abilities, as well as a few tricks we have up our sleeve, we think we will be sitting pretty. And I don’t think that many teams will be able to out do this drive train this year, except for a drive train I plan on doing next year so long as the game calls for it.