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-   -   Video of Mecanum Drive Running Circles Around 6 Wheel Drives (http://www.chiefdelphi.com/forums/showthread.php?t=89737)

indubitably 30-05-2013 18:24

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 
http://youtu.be/rJoqeiuX3lA?t=1m43s

4096 handled the defensive bots well in this match but again, it doesn't necessarily support the mecanum > 6WD argument, just an example that was requested.

Gregor 30-05-2013 18:44

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 
Quote:

Originally Posted by connor.worley (Post 1277840)
To be fair, mecanums have a really really good installation effort / cool factor ratio.

Which make them perfect for demo robots, assuming there will be a flat floor.

EricH 30-05-2013 19:25

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 
Quote:

Originally Posted by Andrew Schreiber (Post 1277836)
FIRST fields ain't level. Also, carpet != wood/tile you'll get drastically different performance characteristics.

This. Also check weight distribution--a climber sticking out the side could be enough to throw off any straight-line maneuvers not going through that side. I don't know how many teams that use mecanums use suspensions any more, but I'd consider a suspension at least worth a look if you don't want to do corrections.

The last truly flat field--no under-carpet bumps or over-carpet bumps--was not 2011. 2009 doesn't count (and had a bump anyways--there was carpet exposed at the edges). 2007, if you weren't climbing a ramp; 2005 if you count the ramps. Yep, 2005. Until you factor in the loading-zone triangles, in which case we haven't had a truly flat field since before automode--in 2002's Zone Zeal.

gabrielau23 30-05-2013 22:23

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 
Quote:

Originally Posted by pntbll1313 (Post 1277630)
I will have to disagree with this post. Last year we were one of the fastest robots at balancing both single and double with mecanum. WE were the ones that pushed robots up the bridge. I'm sure you had a bad experience playing with bad mecanums at your regionals but you can't generalize that all mecanum are this way. Here's a video of us lining up, lowering the bridge, and balancing all in around 4 seconds.
http://www.youtube.com/watch?v=fWYN5xVIyzw&t=11m1s


With Mecanum at our last competition we were hitting 5 cycles with heavy defense and 7 without.

Your opinion doesn't count because you're closer to Michigan than we are. :DDDD

Haha, okay, point taken. But I would venture to say that your team was an exception to the rule at pushing robots up the bridge in Rebound Rumble, n'est-ce pas?
And congratulations on your 10,000 lakes performance!

gobrewcrew95 30-05-2013 23:56

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 
Proof that a 6wd robot is superior...;)

http://www.youtube.com/watch?v=Pu1VCYP4doo

I don't see them using mecanums...:p

Andrew Schreiber 31-05-2013 00:23

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 
Quote:

Originally Posted by EricH (Post 1277861)
This. Also check weight distribution--a climber sticking out the side could be enough to throw off any straight-line maneuvers not going through that side. I don't know how many teams that use mecanums use suspensions any more, but I'd consider a suspension at least worth a look if you don't want to do corrections.

The last truly flat field--no under-carpet bumps or over-carpet bumps--was not 2011. 2009 doesn't count (and had a bump anyways--there was carpet exposed at the edges). 2007, if you weren't climbing a ramp; 2005 if you count the ramps. Yep, 2005. Until you factor in the loading-zone triangles, in which case we haven't had a truly flat field since before automode--in 2002's Zone Zeal.

Except for the pyramid goals... And 04 had the steps, 03 had the hill... so, 02?

EricH 31-05-2013 00:31

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 
Quote:

Originally Posted by Andrew Schreiber (Post 1277944)
Except for the pyramid goals... And 04 had the steps, 03 had the hill... so, 02?

2002, and before then, 1999. Those are the only two games I can think of that had a perfectly flat field. All the others had SOMEthing that was either raised to climb onto or put on a plate under the carpet; 1998 and before I don't know if there was anything underneath but I know some of them had structures to climb on. (2001, limbo bar/4x4 and ramp; 2000, ramp and limbo bar. 1992, corn. 1993, ramp.)

k20002222 31-05-2013 11:22

Team 126
 
You can look up videos on the blue alliance of team 126 this year. Our mecanum drive easily defended 868 in championships also.

jeremylee 01-06-2013 00:38

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 
Here's an example of a mecanum bot (Team 2040 DERT) slowing down 868 allowing us to squeak out a close win at Boilermaker during a qualification match. Going into the match, we knew it was going to be tough to beat 868, so we asked 2040 to do everything they could to slow 868 down and give our alliance a chance.

http://www.youtube.com/watch?v=1XV0VbRaiFg&list=PLR10HG9lJB687vU1Ivd0nnyS TMYcpeN5p

Though I think mecanum is a little underrated, 868's drivetrain / shooting dominated Boilermaker.

pfreivald 03-06-2013 09:29

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 
Quote:

Originally Posted by EricH (Post 1277947)
2002, and before then, 1999. Those are the only two games I can think of that had a perfectly flat field.

There's this persistent idea that mecanum wheels transmogrify into awful willy-nilly machines on a non-flat field.

A. They don't, and can often traverse obstacles with little (or no) more difficulty than standard wheels.
B. All FIRST fields are largely flat, even those with obstacles, giving lots of opportunity for using the omnidirectional versatility of the drive.
C. Even on uneven surfaces, drivers can often compensate, though admittedly it is harder... Then again, the number of teams I saw stuck against the barrier or bridges last year that were WCD or KBoS tells me that this isn't a mecanum problem per se, it's a driver practice problem.

I know this thread is about defense, but TBH where omnidirectional drives shine is in fine control for lining up (at the feeder slot, for example). Mecanum drives are comparatively cheap, easy to install, and easy to program compared to other omni systems, and thus are a reasonable choice for teams looking for omni capabilities without a huge investment of time, money, and energy.

cmrnpizzo14 03-06-2013 10:00

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 
Quote:

Originally Posted by jeremylee (Post 1278066)
Here's an example of a mecanum bot (Team 2040 DERT) slowing down 868 allowing us to squeak out a close win at Boilermaker during a qualification match. Going into the match, we knew it was going to be tough to beat 868, so we asked 2040 to do everything they could to slow 868 down and give our alliance a chance.

http://www.youtube.com/watch?v=1XV0VbRaiFg&list=PLR10HG9lJB687vU1Ivd0nnyS TMYcpeN5p

Though I think mecanum is a little underrated, 868's drivetrain / shooting dominated Boilermaker.

Great defense there, I would say that 2040 probably took away 2 cycles from 868, not an easy task. I didn't really see much driving that was unique to mec's though. I may have missed it so if someone could please point it out that would be great but it looked like most of the maneuvers they performed would have been just as easy with 6W or 8W skid. They may have used sideways pushing abilities while in contact with 868 that I could just not see. Could someone clarify if 2040 used any attributes unique to mec's to their advantage here?

jeremylee 03-06-2013 20:01

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 
Quote:

Originally Posted by cmrnpizzo14 (Post 1278285)
Great defense there, I would say that 2040 probably took away 2 cycles from 868, not an easy task. I didn't really see much driving that was unique to mec's though. I may have missed it so if someone could please point it out that would be great but it looked like most of the maneuvers they performed would have been just as easy with 6W or 8W skid. They may have used sideways pushing abilities while in contact with 868 that I could just not see. Could someone clarify if 2040 used any attributes unique to mec's to their advantage here?

Don't recall anything unique when I looked at it before. Agree that a good 6wd or 8wd would likely accomplish the same task. Just an example of a match that challenged my view of mecanum being poor at defense.


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