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-   -   Bridges and Mecanum Wheels (http://www.chiefdelphi.com/forums/showthread.php?t=99384)

Red_Storm_509 07-01-2012 17:02

Bridges and Mecanum Wheels
 
I wasn't able to get a good look at the material of the bridges at the kickoff, does anybody know if mecanum wheels would have enough traction to get up the bridge?

JaredSanMiguel 07-01-2012 17:05

Re: Bridges and Mecanum Wheels
 
The surface at competition will be HDPE (High-density polyethylene)

I'm not sure how much grip that will provide but I think mecanums will be able to get up and over.

USSMISSOURI 07-01-2012 17:07

Re: Bridges and Mecanum Wheels
 
I do not think that those wheels will work on the bridge very well, i would recommend either the KOP wheels or bigger versions of them.

Donut 07-01-2012 17:29

Re: Bridges and Mecanum Wheels
 
As mentioned it is HDPE, as many ramps and platforms have been in the past.

Nice video with closeups of the bridges on the FRC youtube page:
http://www.youtube.com/watch?v=-AMaq...3&feature=plcp

Answered an important question for me, balls can't get stuck underneath and the bridges return to center with nothing on them.

lcoreyl 07-01-2012 17:32

Re: Bridges and Mecanum Wheels
 
There were teams that used mecanum with no problem on the bumps in 2010 breakaway.

The only difference in traction for mecanum is they will reach their max (friction force) before a regular wheel of the same material. This would be a consideration for pushing contests, but not climbing the bridges.

Ninja_Bait 07-01-2012 21:12

Re: Bridges and Mecanum Wheels
 
The bumps in Breakaway were carpeted, so it was easier for the mecanum wheels to grip.

The bridge is surfaced in polycarbonate, if it makes any difference.

I'm more concerned with the key. That's an HDPE surface, and it's raised an 1/8", which is enough to turn mecanum bots into spin-my-noisy-wheels bots.

CrashTestPilot 07-01-2012 21:54

Re: Bridges and Mecanum Wheels
 
Quote:

Originally Posted by Donut (Post 1098297)
Nice video with closeups of the bridges on the FRC youtube page:
http://www.youtube.com/watch?v=-AMaq...3&feature=plcp

Answered an important question for me, balls can't get stuck underneath and the bridges return to center with nothing on them.

Thanks for pointing this out. There is a lot of other usefull information related to this years game if you watch all other episodes. Was this shown during todays kick off? Somehow I missed this.

jason701802 07-01-2012 22:01

Re: Bridges and Mecanum Wheels
 
I don't expect many high functioning mecanums this year without a quality suspension.

EricDrost 07-01-2012 22:07

Re: Bridges and Mecanum Wheels
 
Quote:

Originally Posted by jason701802 (Post 1098742)
I don't expect many high functioning mecanums this year without a quality suspension.

I don't expect many high functioning mechanums any year :P

Mr_I 07-01-2012 22:12

Re: Bridges and Mecanum Wheels
 
Quote:

Originally Posted by CrashTestPilot (Post 1098728)
There is a lot of other usefull information related to this years game if you watch all other episodes. Was this shown during todays kick off? Somehow I missed this.

These were not shown during KickOff. It would have been very helpful if they were. (Suggestion for next year?)

burnzkid 07-01-2012 22:34

Re: Bridges and Mecanum Wheels
 
Quote:

Originally Posted by Ninja_Bait (Post 1098637)
I'm more concerned with the key. That's an HDPE surface, and it's raised an 1/8", which is enough to turn mecanum bots into spin-my-noisy-wheels bots.

If this were reddit you would have all of my upvotes. Now, think though: I have no experience with Mecanum wheels, but would it be possible to tool-dip each individual little wheel or cover it in some kind of sticky rubber material to allow it for more grip, or would this hinder the side-to-side movement the Mecanums have?

Ether 07-01-2012 22:41

Re: Bridges and Mecanum Wheels
 
Quote:

Originally Posted by burnzkid (Post 1098810)
would it be possible to tool-dip each individual little wheel or cover it in some kind of sticky rubber material to allow it for more grip, or would this hinder the side-to-side movement the Mecanums have?

1) it would not hinder the mecanum's motion. the rolling motion of the rollers is what makes mecanums work, not sliding of the contact patch

2) even with better grip, there's still a problem. for a mec to work properly, all four wheels must be on the ground. once you lift wheel(s) off the ground, it can do weird things.



burnzkid 07-01-2012 22:54

Re: Bridges and Mecanum Wheels
 
Quote:

Originally Posted by Ether (Post 1098819)
1) it would not hinder the mecanum's motion. the rolling motion of the rollers is what makes mecanums work, not sliding of the contact patch

2) even with better grip, there's still a problem. for a mec to work properly, all four wheels must be on the ground. once you lift wheel(s) off the ground, it can do weird things.



Okay, so what you're saying is the second one wheel gets up on that 1/8" platform, one of the others will lose contact and the bot is gonna end up doing the Michigan Rag.

jsmyth 09-01-2012 20:12

Re: Bridges and Mecanum Wheels
 
My question is, since rubber on poly will create much more friction then the bumps in break away, will this cause the wheels to stall up or slow down.

Ether 09-01-2012 20:18

Re: Bridges and Mecanum Wheels
 

Quote:

Originally Posted by jsmyth (Post 1101029)
My question is, since rubber on poly will create much more friction then the bumps in break away, will this cause the wheels to stall up or slow down.

Could you re-phrase the question please? I can't figure out what you are asking.





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