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#46
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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.
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#47
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Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
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 ![]() |
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#48
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Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
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. |
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#49
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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.
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#50
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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.
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#51
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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.
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#52
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Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
Quote:
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. |
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#53
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Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
Quote:
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. |
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#54
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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. |
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#55
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Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
Quote:
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#56
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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. |
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#57
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Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
Quote:
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. |
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#58
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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).
Last edited by klmx30302 : 24-01-2011 at 11:23. |
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#59
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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:
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. |
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#60
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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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