Omni Mania

[JVN]

Originally posted by Mike Soukup
Bill passing Wildstang pictures & videos to John & the rest of FIRST....hmm....that sounds oddly familiar

Mike,
I'm sure I don't know what you're talking about, and... they were all beautiful and inspiring.

John

[ajlapp]

im wondering why you say you didnt need a lot of traction in the 2002 game?! that was the one with the 180 lb goals that had to be dragged into your zone to score

to answer a question.......

we designed specifically to pick up balls and not manipulate the goals, we didn't win, but i'm not entirely sure it was because we ignored the goals.

ajlapp: I'm still amazed at how cool your Kiwi drive is and also how simple & elegant the control system was. Great job with that bot.

thanks mike, by the way, i've got chris ankeny here diligently replicating the StangPS for me! hope you don't mind.

[JVN]

Originally posted by ajlapp
the first and last FIRST Killough, for now

http://stuweb.ee.mtu.edu/~alkrajew/FIRST/kiwi.mpg

Anthony,
Just so you know, we on 229 LOVE that video.
We show it at demos sometimes.

The kiwi-drive itself is wicked cool.
Hopefully we can emulate a quick one at some point. We also loved your *programing* method.

John

[ajlapp]

Hopefully we can emulate a quick one at some point.

thanks again for the compliments.........

we made a quick kiwi out of the edu robot just for demos, worked pretty good, and believe it or not our programming worked without any modification.

speaking of modification, my programming guys are sweating bullets about having to re-write their kiwi code for the new controllers.

[KenWittlief]

can you give a breif explaination of how the joystick inputs are used to control the 3 motors at 120° angles from each other?

its not clear from the video exactly how the bot was intended to be driven - lots of spinning and twirling going on there.

[ajlapp]

i'd love to explain.........what i can anyway.

we used three normal joysticks, connected together with a "y"-shaped yoke, and ball joints. the x-axis of each stick was unwired, and the threey-axis of each stick were wired into one coupler.......just to save space on a cramped IO.

so each y-axis of the joystick represents the velocity vector of one wheel. the joystick does the complex task of converting cartesian coordinates to polar coordinats inherently.

the robot goes in the direction the stick is pushed, or spins if the stick is rotated in the center.

the attached pictures show how the joystick is a vector based model of the real robot......instead of a motor and gear set, you have a potentiometer. you manually input the velocity of each motor and the robot responds. (both pictures were prototypes)


problems!
our drivers created what they called slip. this was their method for driving. it was based on a general direction rather than a finite point in space. they kind of glided the robot to its position. the joystick doesn't make it super easy to go in straight lines, but straight is irrelevant when you can go anywhere instantly.

we worked around this by making multiple faces for our robot to operate on......front didn't really matter.

[KenWittlief]

thanks for the info.

simply awesome!

[Bill Gold]

Originally posted by Joe Ross
I certainly wouldn't discourage 702 from working on a swerve drive, whether or not they design their robot around it. They have the added bonus that they would be only the 2nd team to have a working swerve on the west coast (258 being the first).

Actually, team #360 from Seattle, WA (my former physics teacher's current team) had a double shaft swerve in the 2002 competition. Also, team #998 from Alaska had a double shaft swerve this past season (2003).

Originally posted by Mike Soukup
Bill passing Wildstang pictures & videos to John & the rest of FIRST....hmm....that sounds oddly familiar

At least I told you before more than 8 IPs downloaded the pics/vids. Don't I get any credit for that? By the way, it wasn't me who passed the url to John. There was in intermediary .

Here are a couple of pictures from 111's 2002 Inventor Award submission.
http://www.seadawgs.com/111/eng.jpg (two engineering drawings)
http://www.seadawgs.com/111/DSCN0736.jpg

Here are a few pictures of 258's 2003 drivetrain.
http://www.seadawgs.com/258/cimgearbox.jpg
http://www.seadawgs.com/258/cimassembled.jpg
http://www.seadawgs.com/258/cimassembled2.jpg
http://www.seadawgs.com/258/cimassembled3.jpg
http://www.seadawgs.com/258/cimassembled4.jpg
http://www.seadawgs.com/258/cimassembled5.jpg
http://www.seadawgs.com/258/drillgearbox.jpg
http://www.seadawgs.com/258/drillmounted.jpg

I've got drawings for all of 258's drivetrain components if anyone's interested, as well.

<edit>
I forgot to mention that I'm working on a paper describing the entire design process that led to 258's swerve drive this year. My goal is to use this in the WRRF's Motors/Drivetrain class in November and December.
</edit>

[FotoPlasma]

Originally posted by Bill Gold
Actually, team #360 from Seattle, WA (my former physics teacher's current team) had a double shaft swerve in the 2002 competition. Also, team #998 from Alaska had a double shaft swerve this past season (2003).

Also, team 159, Alpine Robotics from Fort Collins, Colorado, for all intents and purposes, had as much of a swerve system as we did (I consider them far enough west to be "west"). It's too bad, though, that they had some technical difficulties at the Silicon Valley Regional, in 2003, and were forced to lock two of their gearboxes, and install casters, if I recall correctly.

Team 668 had the preliminary workings of a swerve system, as well, but again, due to technical difficulties, it wasn't functional for competition.

Credit where credit is due...

[Tytus Gerrish]

its all because were all too lazy to turn our bodies in the rite directioin

[JVN]

Originally posted by Bill Gold
I've got drawings for all of 258's drivetrain components if anyone's interested, as well.

<edit>
I forgot to mention that I'm working on a paper describing the entire design process that led to 258's swerve drive this year. My goal is to use this in the WRRF's Motors/Drivetrain class in November and December.
</edit>

Bill,
We're thinking about a swerve for 2005 (when Eric and I are in Senior Integrated Design class, and get to do FIRST for a grade). So I'm already gathering ideas/concepts. I'd love any information you'd share, and would be VERY interested in you're paper.

(brief aside: I'm working on a similar paper for some of the technology we're currently developing.)

I like to think of your swerve drive as "the working man's swerve". Unless I'm missing something, it seems like one of the *easiest* to fabricate. 229 has CNC manufacturing, but nothing really above that.

John

[Sachiel7]

Hmm, that's a really cool design!
Mine does not have the motors on the wheel assemblies, however, and it uses more chain than gears...
I'll let you know how it turns out...all the prototypes so far have worked...
I'm not really sure who has had a crab/swerve drive here on the east coast...
I'm pretty sure there was 1 I remember from this past year...maybe we'll be the second?!
Heh...

[SpaceOsc]

Go 702 !!!!!!!!!! lol lil team pride


But anyways thanks for alot of the help you guys have lead me into odd and weird directions with this thing.. ill try wiht one of the mentors to build a prototype from a pre existing frame except were not trying a crab drive despite the obivious love affair you all have with it.. 702 going with a omni drive using all omni wheels in standard omni setup tho i do realize the obvious set back of less traction its alot simpler to build for now and the teams a lil weary on difficult new desings so they needed to be wowed right now with omni drive maybe well head in the crab direction later

does anyone one know where to get already made omni wheels.. i found a few places but does anyone one have somethign they already know is good?

[Matt Reiland]

Originally posted by Mike Soukup
There may be better pictures around our gallery, and I'm pretty sure Matt Reiland has some good closeups too.

Hmmm how about this......

[SpaceOsc]

Greatly appreciated

But i shoulda made it clearer I WANNA BUY WHEELS!!!!!!

lol thanks for the the pic tho ::drools ::