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

Chris is me 23-01-2011 20:19

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 
That's about the free speed 971 was running at in the above video.

Vikesrock 23-01-2011 20:22

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

Originally Posted by wilsonmw04 (Post 1006768)
16 FPS? That's a bit quick for an FRC field don't you think?

From the 254 website:
2010: 15.5 FPS (high gear)
2009: 15.4 FPS
2008: 18.5 FPS (high gear)
2007: 16 FPS (high gear)
2006: 16 FPS (high gear)
2005: 14 FPS (high gear)
2004: 15 FPS

So no, he probably doesn't think so ;)

thefro526 23-01-2011 20:23

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

Originally Posted by wilsonmw04 (Post 1006768)
16 FPS? That's a bit quick for an FRC field don't you think?

Not really. It's usually the high gear of a 2-speed transmission. The Poofs have had a top speed of somewhere in the 15fps + range for as long as I can remember. (And for as long as I can remember they've been kicking butt, so I guess it works.)

On the subject of Mecanums and out-driving 6WD's, I'm fairly confident in saying that it IS possible, but hasn't happened yet. Mr. Lim's video is a good showcase of what a Mecanum is capable of with decent drivers, but the field last year wasn't really big enough for a Mecanum to fully stretch it's legs.

It seems that many teams that pursue both Holonomic and Mecanum Drives do not invest enough time in training their drivers to fully utilize the omni-directional motion these drives are capable of. More often than not, I see many Omni-Drive robots driving EXACTLY like a skid-steer until they need to move left or right a hair. I would absolutely LOVE to get my hands on a well built Mecanum or Holonomic drive just to see what happens.

Chris is me 23-01-2011 20:26

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 
It's worth noting that a 15 FPS free speed is faster than most drivers can handle without experience and / or practice - one of the reasons veteran teams build fast bots that are so well controlled is because of their extensive practice time.

SudoSammich 23-01-2011 20:30

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 
Like everyone else I wish TBA was up to get a video, but our team's going with a holonomic drive this year partially as a result of our experience with team 263 (aftershock) at the Long Island regional last year. We seeded first at the end of the qualification rounds due to our scoring ability and won an offseason competition in October thanks to this same ability. The most effective defensive team at the regional in our eyes was 263 by far, and they shut us down for a good portion of the match each and every time we were against them. It's not exactly what you were asking for (the mecanum bot was defending, not scoring), but watching them last year left quite the impression. We'll see how holonomic drive works for us, but right now I'm feeling pretty confident in it's potential at least.

Bjenks548 23-01-2011 20:34

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 
I'm not positive about this, but I heard somewhere that mec drives have never been on Einstein in FRC. I think the cons of a mec drive outweigh the cons of i well built 6wd. The biggest of these being practice time for drivers.

efoote868 23-01-2011 21:58

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

Originally Posted by Bjenks548 (Post 1006801)
I'm not positive about this, but I heard somewhere that mec drives have never been on Einstein in FRC. I think the cons of a mec drive outweigh the cons of i well built 6wd. The biggest of these being practice time for drivers.

Considering mecanums in FRC was pioneered by (if memory serves me) team 357 in 2005, and since they've only become "popular" since their commercial introduction by AndyMark in 2007? And since in 2009 they weren't allowed, I'm not surprised.

From personal experience, field centric mecanum drive is about a hundred times easier to learn to control than a traditional tank drive.
Which is to say that practice time for drivers is an advantage of holonomic drives, not a disadvantage.

thefro526 24-01-2011 08:16

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

Originally Posted by efoote868 (Post 1006886)
Considering mecanums in FRC was pioneered by (if memory serves me) team 357 in 2005, and since they've only become "popular" since their commercial introduction by AndyMark in 2007? And since in 2009 they weren't allowed, I'm not surprised.

From personal experience, field centric mecanum drive is about a hundred times easier to learn to control than a traditional tank drive.
Which is to say that practice time for drivers is an advantage of holonomic drives, not a disadvantage.

That being said, 357 has used Mecanum wheels since 2005 (with the exception of their swerve in 2009), 148 used them in 2006, and a handful of other teams used them prior to the AM versions. Also, traditional Holonomics have been around since at least 2002, and I don't believe one has made it to Einstein.

Whether it be field centric, or robot centric, it seems that Mecanum Drives and Holonomics are usually not as well driven as a similar Skid Steer or 6WD. Chalk this up to a harder learning curve, less driver practice, or whatever, but one has still not made it to Einstein.

dmitch 24-01-2011 08:27

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 
It is not the driver that chooses the drivetrain, but the drivetrain that chooses the driver.

Pick one and go with it and any good driver will be able to make it work for you.

That being said, mecanums will be easier to align with the goals because they do not have to turn. Just my two cents.

JamesBrown 24-01-2011 09:13

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

Originally Posted by efoote868 (Post 1006886)
Considering mecanums in FRC was pioneered by (if memory serves me) team 357 in 2005, and since they've only become "popular" since their commercial introduction by AndyMark in 2007? And since in 2009 they weren't allowed, I'm not surprised.

From personal experience, field centric mecanum drive is about a hundred times easier to learn to control than a traditional tank drive.
Which is to say that practice time for drivers is an advantage of holonomic drives, not a disadvantage.

190 also had Mecanums in 2005.

JesseK 24-01-2011 10:36

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 
Once TBA comes back up, look at 1086 & 384 at VCU in 2007. I'm not so sure about the "drives circles around" claim, but they were very quick and agile. The drivers performed with such tenacity that any errors were quickly resolved by trying again. They were in the 13-14fps (free speed) range.

384 also used their Mecanum to play effectively during 2008 at VCU and in Atlanta. 1086 had the same drive train (and made it to Champ. elims), but 384 made it to the division finals (only to be trumped by the 1114/217/148 power house).

Which reminds me: Tumbleweed DID run circles around standard 6WD skid. However, 148 focused so well on coaxial crab design that year, we shouldn't have expected anything less.

thefro526 24-01-2011 10:55

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

Originally Posted by JesseK (Post 1007123)
Once TBA comes back up, look at 1086 & 384 at VCU in 2007. I'm not so sure about the "drives circles around" claim, but they were very quick and agile. The drivers performed with such tenacity that any errors were quickly resolved by trying again. They were in the 13-14fps (free speed) range.

384 also used their Mecanum to play effectively during 2008 at VCU and in Atlanta. 1086 had the same drive train (and made it to Champ. elims), but 384 made it to the division finals (only to be trumped by the 1114/217/148 power house).

Which reminds me: Tumbleweed DID run circles around standard 6WD skid. However, 148 focused so well on coaxial crab design that year, we shouldn't have expected anything less.

384 & 1086 (I believe there was also a 3rd twin) in 2007, and also 1086 in 2008 were by far some of the most well driven Mecanum Wheeled robots to ever seen an FRC competition. If any robots had a chance of out performing a 6WD they may have been able to do it, but my exact memory is a bit fuzzy and I don't know if they ever actually did, in fact, drive circles around a well driven skid steer.

Also, I believe everyone in this thread agrees that a well built Swerve, be it a Wildstang style, or a Coax has the capability to out drive a Skid Steer, and has been proven to do so. Perhaps one of the best examples of this, also from 2008 would've been Team 16. 148 did use their's quite effectively, but their small footprint also played into their ability to out drive other teams. If I remember correctly, the Team 16 Robot had a HUGE foot print (Something like 38" x 60") and still managed to out maneuverer darn near anything that got in it's way.

klmx30302 24-01-2011 10:56

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 
Our team will likely be creating a practice bot after the competition bot is done so our drivers will have time plenty of time to practice with mecanum drive before our week one competition (GSR).

germansamurai16 24-01-2011 18:31

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 
Originally Posted by wilsonmw04 View Post
16 FPS? That's a bit quick for an FRC field don't you think?

Quote:

Originally Posted by Vikesrock (Post 1006781)
From the 254 website:
2010: 15.5 FPS (high gear)
2009: 15.4 FPS
2008: 18.5 FPS (high gear)
2007: 16 FPS (high gear)
2006: 16 FPS (high gear)
2005: 14 FPS (high gear)
2004: 15 FPS

So no, he probably doesn't think so ;)


16 fps is pretty much what our team had normally, except for 2008 where we had a top speed around 22 FPS. It does seem a little high, it did back then too, but physics doesn't lie.

wilsonmw04 24-01-2011 20:41

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 
I get that is possible and has been done before, but I still would wonder how useful it really is. How much time each match did you spend at the top speed?(barring OverDrive)

Bah, this is a topic for another thread...


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