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-   -   pic: Team 980's arm hitting the stack at 2 seconds on clock (http://www.chiefdelphi.com/forums/showthread.php?t=19639)

DougHogg 30-03-2003 20:10

Quote:

Originally posted by Pin Man
Which regional was that? Arent you top heavy with that arm?
That was the Arizona Regional.

We are definitely heavier up top than most of the robots this year, but we never tipped in our 15 matches in Arizona, or in any of our practice matches.

Pin Man 30-03-2003 20:36

I see...

DougHogg 31-03-2003 03:28

Quote:

Originally posted by Gope
Wow, thats fast, faster than Beatty even, but you might be careful with it, our auto mode hits the boxes in 2.75 seconds and Beatty was around 2.5..In the quarter finals at the Mid-West regional we caught their arm on our way over the ramp and flipped them over in auto mode rendering them useless for the rest of the game, be carefull you also don't become the victim of a very fast very low CG robot.
We were just watching SOAP108's video's of Beatty (Team Hammond #71). (Finally got Windows Media Player working on my Mac but had to reload the movies every time until just now when I finally found a way to download the movies.)

The "Beast" looks very fast. In fact in the videos, it looks just as fast as our arm, and their swing is concluded faster. It would be another interesting match if we wind up competing with them. Of course, one of these days we will be allied with another arm and that would be interesting as well.

We watched videos of Team 16 also. Amazing how you scream around that corner! If it isn't a trade secret, how do you do that? I would love to see your matches in the elimination rounds, but I couldn't find them. If the elimination rounds for the MidWest are online somewhere, I would love to hear about it.

Anyway, thanks for the forewarning. We haven't tipped yet and it would be nice to continue that trend. Hopefully our arm would glance off you and bounce up, since we hit higher on the stack than Beatty.

See you in Houston. I think it's going to be very interesting this year.

Matt Brinza 01-04-2003 01:51

Doug:

Soap108.com has updated their site, and have uploaded the elimination matches. I suggest you watch QF4.1! ;) You'll notice that 71 positioned their robot opposite ours for QF4.2 (their auton worked nicely that time).

Look forward to seeing you again at Nationals!

DougHogg 01-04-2003 02:36

Quote:

Originally posted by Matt Brinza
Doug:

Soap108.com has updated their site, and have uploaded the elimination matches. I suggest you watch QF4.1! ;) You'll notice that 71 positioned their robot opposite ours for QF4.2 (their auton worked nicely that time).

Thanks Matt,

I received an email from shawny963 of Team 930, one of your alliance partners from the MidWest, letting me know about the videos, and I just watched SF2m2. I sure do like your robot! Awesome!

I haven't seen QF 4.1 yet. It is hereby moved to the top of my list.

Quote:

Originally posted by Matt Brinza
Look forward to seeing you again at Nationals!
Hey, we are looking forward to seeing you. I hope that we are in the same division. In fact, Team 16 is our number one choice for a running partner, if the fates are so kind to us. Of course the odds are against us being in the same division and everyone will have to see how various robots will work together. We understand that. But we are making some very interesting enhancements on Thursday at the S. Calif. Regional, and we plan on being very much in the running in the Nationals. Time will tell, but being partnered with you guys would be amazing.

See you in 10 days. (Wow, we are going to be busy for the next while.)

T967 01-04-2003 12:25

slr
 
I was at the ST. Louis reg. and can tell you that baxter's bot is A L I V E. The thing knows what it's doing were it is and can really mess yah up in auto. It hits the stack and then procedes to do crazy things like back up and go at another stack, flail around after hitting the stack, hit the stack and keep going at that insane speed of theirs. One match somethan' broke though and it went nuts about half way up the ramp. It's scary how it always seems to do the correct thing though.

Kojib 01-04-2003 12:40

How we do it.
 
Basically, very strong drive-train and dead reckoning. We are 3-WD, with Bosch drill motors locked into highest setting on front wheels with 4:1. Our Rear wheel is powered with both Chiaphuas. They drop into a helical gear set which sends a shaft through the center of the wheel (on bearings) into a planetary set (the sun, more specifically). We then simply bolt the planets to an aluminum hub we fabricated for the wheel, giving us 15.66:1. The entire rear assembly rotates 180' using a globe motor and a cable (it rests on 102 lycra ball bearings). As the rear assembly rotates, we slow down one of the front wheels to keep it from binding through turns. This gives us approx. 12 fps with enough torque to drag me (160 lbs, 5'8") lying down across carpet (also up the mesh and the HDPE, but I don't like repeating those experiments). All three wheels are 8" Skyway pneumatics inflated to approx. 17 psi.

Pin Man 01-04-2003 17:33

It's hard to believe that 2 seconds... thats fast... i'd have to see it to believe it...

DougHogg 01-04-2003 17:59

Re: How we do it.
 
Quote:

Originally posted by Kojib
Basically, very strong drive-train and dead reckoning. We are 3-WD, with Bosch drill motors locked into highest setting on front wheels with 4:1. Our Rear wheel is powered with both Chiaphuas. They drop into a helical gear set which sends a shaft through the center of the wheel (on bearings) into a planetary set (the sun, more specifically). We then simply bolt the planets to an aluminum hub we fabricated for the wheel, giving us 15.66:1. The entire rear assembly rotates 180' using a globe motor and a cable (it rests on 102 lycra ball bearings). As the rear assembly rotates, we slow down one of the front wheels to keep it from binding through turns. This gives us approx. 12 fps with enough torque to drag me (160 lbs, 5'8") lying down across carpet (also up the mesh and the HDPE, but I don't like repeating those experiments). All three wheels are 8" Skyway pneumatics inflated to approx. 17 psi.
Are you shifting gears to get that kind of speed as well as torque?

I gotta see the two Chiaphuas hooked up to one wheel. Very cool.

See you in Houston.

Jnadke 01-04-2003 20:37

Re: Re: How we do it.
 
Quote:

Originally posted by DougHogg
Are you shifting gears to get that kind of speed as well as torque?

I gotta see the two Chiaphuas hooked up to one wheel. Very cool.

See you in Houston.


Nope... They're pure speed from the moment they move.

You gotta see it to believe it, 16 is definately THE fastest robot at MR... pretty much twice as fast as the fastest bot there.

It's pretty interesting how they did that... used 4 motors but differently. I suppose it works really great looking at it...


Beatty isn't really that great, they had major problems even making it up the ramp. I suppose that will be solved by nationals with higher traction wheels. Their arm can get the stack, but it's a telescoping PVC arm. Any bot like 16 can easily overpower it and tip ther robot, it's just a matter of getting there before they do. It also tends not to fully telescope outward, so they usually get anywhere from 1/4 to 3/4 of the wall.

DougHogg 01-04-2003 20:49

Re: Re: Re: How we do it.
 
Quote:

Originally posted by Jnadke
Nope... They're pure speed from the moment they move.

You gotta see it to believe it, 16 is definately THE fastest robot at MR... pretty much twice as fast as the fastest bot there.

With that much speed, I would have thought their torque would be limited. How can they drag someone up the ramp?

(Hm...very interesting, Dr. Watson. The mystery will be solved in Houston.)

Gope 01-04-2003 20:50

We put both chips on the same wheel with a 15.66:1 gear ratio, it gives us plenty of tourque and insane speed! No shifting involved at all.

Not to mention the fact that we're making radial movements while everyone else is making linear movements, which makes us turn a whole lot faster than anyone else.

Jnadke 01-04-2003 21:03

Re: Re: Re: Re: How we do it.
 
Quote:

Originally posted by DougHogg
With that much speed, I would have thought their torque would be limited. How can they drag someone up the ramp?

(Hm...very interesting, Dr. Watson. The mystery will be solved in Houston.)


Torque and Speed are directly related if you look at a Torque-Speed curve of a motor. As one goes up, the other goes down. Torque is the pushing power of the robot. It is also what causes the acceleration of the robot.

With that said, using 4 motors, a lot more torque can go to the wheels, causing the robot to accelerate much faster. Even though they have the wheels geared rather high, they get up to speed rather quickly. Once they get up to speed, torque isn't a factor, so speed takes over, which allows them to go rather fast.

It's more complex that that, but that's the gist of it.


As for hooking up two motors in unison, it's not unheard of. We (269) have 2 chiaphua motors connected in unison on our transmission for the differential. It's needed for our car-style steering, which allows us to move in radial and linear movements much like 16. Although we are not as fast as 16, our radial motion allows us to get to the wall faster than ordinary robots.

Kojib 01-04-2003 21:28

Actually, when we were designing our drive train, we had made the same mistake twice which really helped us. We misinterpreted the charts for the drill and chip' motors. We planned on them putting out about 2/3 the power they actually do. When we ran it for the first time, we were all stunned as we had been planning on about 7-8 fps. It took a few days to figure out what happened, but we weren't too hard on ourselves. *grin*
If you like, I can give you a full run-down of our robot at nat's. Just go to our pit and ask for either Garrett (me) or Jesse (Gope). Actually, anyone could give u the robot run down, but Jesse and I know it forwards and backwards. Also, Jesse is on our compliance team, so he could probably get CAD drawings if you like.

DougHogg 01-04-2003 21:48

I want to see both those robots (16 and 269) at the Nationals.

We have a neat shift on the fly arrangement with 8 full-time wheels powered by the 2 chiaphua's. We set 4 wheels down at a time, and with our 4 inch wheels, we can push really well.

We are making a few changes on Thursay, which will allow us to spend more time in high gear (using 8 inch wheels), so we will be faster than we were in Phoenix, but we aren't going to try to drag race with Teams 16 or 269.

Anyway, thanks for the info.


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