pic: FRC973 Testing Bridge Stability

Testing the stability on our bridge at home. The robot makes it to 45 degrees before it loses traction and slides, and it still hasn’t tipped by that point!

Where’s the top part? I only ask in the name of science. :cool:

I don’t think the shooter mechanism is on, 973 seemed a lot taller at CVR.

It’s on there, it’s just not powdercoated.

Adding bumpers probably also made a non-negligible change in your CG position.

It would lower our CG though.

Right, just saying. It might even offset the contribution caused by “the top part” (which you just said was on there, but doesn’t quite match the other picture).

What kind of tread do you have on your wheels?

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Wedgetop tread. Not sure the actual source. Adam can back that up though.

Looks like Wedgetop tread from Andymark

That’s what I figured it was but I just don’t understand how that is possible without tread that deploys epoxy between itself and the bridge.

From what I hear, wedgetop tread has more traction on surfaces like hdpe than roughtop or blue nitrile tread. That’s the main reason most top teams used it.

Also, I’m not sure if the robot has an active breaking system on it or not. That could help. 256 had software breaks that worked so well we could be at a 45 degree angle and still stay where we were without falling. Of course, these disabled when the robot was turned off.

also, with swerve you can turn your wheels parallel to the axis of rotation of the bridge, so that your wheels don’t turn at all.


It’s also AndyMark supplied wedgetop.

the robot is missing the bridge mech in this pic, but that’s only ~3 lbs and doesn’t apreciably affect CG. The shooter as it exists on comp bot is on this in all it’s heaviness.

Cool, swerve! Does anyone know if there are higher resolution pictures of the modules on CD?

The modules are pretty similar to what is posted in the CAD in my sig.

The wheel modules are 99% the same, the corner modules are 80% the same.

Adam I have been meaning to ask, who came up with your front intake system? The side to side capability is a ingenious idea. I was wondering if it was a after though that was added on later or in the original design.

The first incarnation of that mechanism in FRC that I know of was Chief Delphi VII in 2002.


It has been very effective this year, utilized by 973, 177, 1477, 2415, and others at various points this season. It was also featured on a couple of 2006 robots, most notably team 27’s (they also used the same concept in 2008).

We also use this system on our robot. We call it the “Joe Johnson.” It funnels balls down to a single column awesomely well.

Any chance 973 will post their 2012 rebound rumble robot CAD for the world to see?