Successful Stack Stealers

[Alaina]

I always knew they existed, but I hadn't even heard of stacks being successfully stolen. But at SVR team 115 stole a stack of 2, went over the ramp with it and placed it in their scoring zone. I can't quite remember whether is stayed or not but I was very, very impressed. Has anyone else heard of/seen stacks stolen?

[JVN]

213 - Dirty Birds stole a 4 stack at BAE.

[Arrowsmith]

We stole a stack of three at Chicago.

[AJ Quick]

We stole several stacks of 1.

[roboticscom13]

At Philly team 357 Royal Assualt stole a stack of two or three in our last match and could do it again if needed.

[Jupee]

We've definitely dirty-snatched at least three or four stacks thus far. Just you wait til nats--we'll be doing the same old stuff

[dhendrix]

We never had the opertunity to go over the ramp with a stack in St. Louis, but we did it in practice events. We have a Gyro programmed to a tilt that will keep the stack level as we go over the ramp at full speed. Really Cool.

[Guyute]

why go over the ramp when you can simply drop the stack over the bar.

[OneAngryDaisy]

Originally posted by roboticscom13
At Philly team 357 Royal Assualt stole a stack of two or three in our last match and could do it again if needed.

Yeah that was awesome-you guys flew over the ramp and casually grabbed the stack on the fly..

[activemx]

actually MVRT stole stacks of 3 several times during the elimination rounds and stack of 2 during semifinals.. It survived every time it was stolen.
btw.. videos are here ~ http://www.chiefdelphi.com/forums/sh...threadid=19803

~ Akshay

[codeoftherobot]

The only problem with stack stealers is that their size can normally their downfall. If they want 3 or more boxes the center of gravity shifts when those extra boxes are taken on. Once they are at an angle on the ramp, the robot can be very unstable and prone to be knocked over if hit at the correct angle by another robot. If you are a stack stealer team, watch out for small quick robots since they can take you out really fast.

[Solace]

you'd be surprised at how steady a robot can be even when holding four bins or so. We can go full speed over the ramp (12 ft/sec) while holding 4 bins without tipping, and can proceed to blow doughnuts. Its all about having a low CG to begin with - most robots who steal and protect stacks have innately high CG's, but there are some that manage it with a low CG.

If you're a team that has a problem with tipping, remember the all-powerful wheelie bar!

[jburstein]

MVRT also got themselves tipped over nearly every time they tried to cross the bridge with a stack. I saw them in 5 or so matches and they got tipped in 3 of them, and only narrowly avoided it in the other 2.

[activemx]

well the three matches we got tipped on it was not because we were moving stacs.. we were just hit by robots.. Though every time stole the stacks we did not tip over. Its true that stackers have High CG generally. WE do have a high CG but we dint tip over with a stack but now we our driver has faced and knows about the tipping broblem that we drive with our 4 bar out and support the 4 bar with caster. SO in that way we can never tip over. If you wanna see the thing im talking about check out our video. You can also see the cool Wheeeeliee up the ramp with stack of 3.

~ Akshay

[Patrick Wang]

Akshay forgot to mention that we also protect the bins from any attack. The bins are totally enclosed while in transit and while awaiting placement on the far side. The more important part is keeping the stacks alive rather than simple moving them over.

As for the tipping issue, watch our videos of our qualification rounds to see our high CG problem, and then watch the video of our Semi-Final round to see how we solved it. It was kind of a head-slapper, totally a driver issue. Lowering our 4-bar linkage increases our wheel base to about 60 in and lowers the center of gravity as well.

Expect us to be doing more of that in autonomous and driving overall, it's pretty hard to tip over for us when the linkage is down because 75% of our weight is already in the drive train and the other 25% gets lowered to only a few feet above.