I know there alot of debate on this subject but I think this is the year we will see a set of mech’s on einstein. I say this because were seeing a flat playing field so mecanums will be very effective. Plus mecanums and there drivers have progressed over the years in 2007 most teams made there own or they didn’t know how to use them but this year we have great choices from andymark and our drivers have gotten very comfortable with the drivetrain, I think these are all good factors that might lead to a mecanum getting on Einstein
I disagree. Mecanums can be easilly pushed around, which will be very detrimental this year. They will be very poor at defense, as well as slow(er) than other types of wheel base. Speed will be extremly important this year, unless you have someone ferrying you pieces. A good 6 wheel, 8 wheel, or treaded robot will have lots of fun pushing around the mecanums, away from their lanes, and away from their poles, as well as delaying them in the middle.
All drive trains can be exactly the same speed, it all depends on gearing. I would actually expect the average mecanum speed to be faster than an equivalent tank drive due to the fact that a mecanum bot gains nothing from gearing slow, while a tank bot gains pushing ability.
As for the original topic, yes, mecanums stand a chance this year. Yes, one may make it too Einstein if it is driven effectively.
The flat field is a good point, in that mecanums won’t have issues with having to go directly perpendicular to the slope. More so than previous years, mecanums have a legitimate chance of making Einstein. With defense limited to central areas, mecanums will have much less of an issue scoring than in 2007 (maybe even an advantage over other drive systems, this year). That said, getting through the central deadlock without getting pushed around may be an issue. Quick mecanums that have lots of skill in scoring (don’t need to ever play defense) may be some of the higher picks this season.
I hope we will see a slide drive on Einstein, but other than that i don’t think anything on Einstein will be mechanum, crab, or omni, simple reason: speed, although Mechanums can be geared to the same speed as a tank or other drive, 4 shifting gearboxes would be a little bit of weight. anyone who has a shifting gearbox up near 16+ feet per second is going to score more.
I think there may be a decent chance this year. I think this year sets up best for mecanum since 2008. In 2008, three of the division finalist alliances had a mecanum robot (2171 in Curie, 842 in Archimedes, and 384 in Galileo…although I THINK each of those teams were the 3rd robot on their alliance). I don’t think mecanum is that far off from making the biggest stage.
There were plenty of successful mecanum bots that year (2337 in 2008 was Curie second seed, though were knocked out by eventual Einstein finalists). Maybe the flat field is the key? This year may be a good indicator.
I don’t think the teams that make it to Einstein this year will be because of the drive. I think autonomous and end game will define Einstein this year.
Mecanums naturally take more programming, so it takes away from developing a perfect autonomous. I think we may very well see a veteran mecanum( a team that has had mecanum since 09) but unlikely for a rookie mecanum (a team that hasn’t done mecanum since 09)
After watching our team’s mecanum run for the first time, I’d say unlikely. I mean, it’s not bad… It’s just not what I thought it would be.
By crab, I’m assuming you mean swerve. If memory serves me correctly, there has been at least one swerve drive on Einstein in 5 of the past 6 years, 67 in 2005, 71 in 2007, 16 in 2008, 111 in 2009, and 1625 in 2010. (I believe there was one in 2006, but I don’t remember off the top of my head).
In any case, I doubt we’ll see some sort of pure Holonomic or Mecanum Drive on Einstein just because more often than not, they aren’t driven as well as most skid steers - though there are a lot more factors than just drive train that determine a teams success.
I wouldn’t be surprised if we saw some sort of Octocanum, or other Hybrid drive on Einstein this year since some extremely high caliber teams are working with them, which means that they should have the practice, strategy and end effectors behind them to be successful.
On the subject of speed of omni-directional drive, Multi-speed Transmissions don’t have anything to do with success, neither does top speed (assuming you’re fast enough to be competitive, I’d say minimum of 9/10fps). You can have a top speed of 16fps, but the game will dictate if you can ever actually go that fast. Assuming the field is unobstructed - Which it NEVER is - the faster robot would always score more if all other things are constant. Add in some minor obstructions that need to be maneuvered around, and the top speed may as well be 12fps. (also, it seems that many people are underestimating “threading the needle” to get to the feeder station. It’s not all that hard to do with some practice, I was able to do it at around 11/12fps after playing around after a minute or two, but there’s no way you’re flying in there at 16fps without rubbing the tower or wall.)
But, if multi-speed transmissions are truly the determining factor, then a multi-speed swerve, which isn’t unfeasible (118 has built a few), would have some advantage.
We debated this very subject at start of season and decided to stay with 8” Mecanum wheels. We played center zone last year and had no trouble pushing other teams around, inadvertently tipping several over while managing to hold our ground against 6 and 8 wheel drive Bot’s. In the off season we worked perfecting the degrees of freedom Mecanum wheels offer. It’ll be the skill of the drive team that plays and wins on Einstein not the type drive base, just like it was in 05.
This.
The Breakaway on Einstein was intense. Seeing the robots score 2-5 balls in autonomous was absolutely amazing. That few point lead some teams got in autonomous did set the outcome of the game.
I still think that hanging wasn’t worth enough points, though. Considering not many teams actually managed to successfully do it.
Here we go again, yet another mecanum vs non mecanum thread.
Anyway our team is using 6" mecanum wheels and 9:1 banebots transmissions, our initial tests show speeds of 8+ feet per second.
Seeing as it seems that the last time mecanum drive really had a chance was 2007 I am not sure what will happen this year.
Last year was the first year team 842 used mechanum. What we had that year in 2008 was 2 back wheels driven by super shifters with omnis in the front of our robot.
Probably what he meant, but not the usual usage:
http://wiki.team1640.com/images/4/44/Pivot_-_Crab_with_a_Twist_edit2.pdf
In Crab Mode, all wheels steer together and drive at a common speed thereby steering the robot in any direction on the 2-d playing surface (true 2-d drive). As described above, this mode does not allow overt control of chassis orientation.
http://botshop.wordpress.com/2009/06/22/
all the wheels ALWAYS point in the same direction… allowing the robot to instantly head in any direction without turning, but ironically making it quite difficult to actually turn the robot! Sometimes you will see this referred to as a “Crab” (or “Krab”) drive, because of the way the crab like movement of the machine.
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The best most practiced drivers will make it to Einstein just like every year. It doesn’t matter what kind of drive it is.
If I were I betting man, I bet a lot of money that we won’t see a mecanum bot on Einstein…
Mecanum’s advantage is not in a flat field, it’s in a tight area where you don’t have room to change your orientation. FIRST never has a field with so many obstacles that you can’t re-orient. Mecanum will be an equal the same this year as in past years. Mecanum serves no practical advantage on a FIRST field. Nothing has changed that this year.
Just like the past, we will not see a mecanum bot on Einstein.
67 in 2005 had 3 wheels and did not swerve they drove their bot with a steering wheel and used the back wheel to “steer” their bot around.
842’s 2008 robot was 2 traction 2 omni.
I thought it would happen in 2010 not on merit but on sheer volume, yet the alliances with no mecanum robots consistently won.
I suspect 2011 may break the cycle, not because mecanums are at an advantage but because of luck and volume.
I believe all three wheels were turreted.
67’s 3 Wheel Swerve can clearly be seen in this picture: