Re: Robowranglers 2014: Vader
 

I'd be amazed if any of the elite teams didn't plan on it from day one.

Great video, and great looking robot, 148!

Re: Robowranglers 2014: Vader
 

This team is where Rosie the Riveter gets her rivets. Anyone know how many are on this robot?

Re: Robowranglers 2014: Vader
 

I would put my money on detecting ball acquisition in auto.

Re: Robowranglers 2014: Vader
 

This is totally fake. Where's the secret endgame mechanism? I refuse to believe that 148 would ignore the point bonus that we don't know about yet.

Re: Robowranglers 2014: Vader
 

Anyone able to enlighten me on why the bowed out frame? I would imagine there's some reason...

Re: Robowranglers 2014: Vader
 

Care to share material is on the el toro?

Edit - added:

Btw nice job on the mechanism that "narrows" up the sticks while it lowers. Very slick and one of those things that you don't notice at first.

Re: Robowranglers 2014: Vader
 

Go to 1:24. it looks as if they have a high traction/mecanum drivetrain

Re: Robowranglers 2014: Vader
 

It depends on the angle of the fork. As the wheels turn, if they are geared correctly, they will actually try to walk down more under the robot and put additional force on themselves. Think of the way that a rear wheel drive car transfers weight to the rear when it accelerates. In this case you aren't shifting the robots weight, you're using the leverage of the drive to push down into the floor harder.

As to the why: every tried to get 5 legs of a stool all the same length? Articulating that wheel is necessary - pneumatically or otherwise. I'd guessing this is a way of not using more pneumatics.

We have a little bit of familiarity with a slide-drivetrain. We tried one in 2008 but we hard-connected the wheels to the frame and quickly discovered why you absolutely MUST have mechanical compliance to insure all the wheels are on the ground. What they have here appears to be a refinement of their 2010 drivetrain.

Re: Robowranglers 2014: Vader
 

:yikes: That makes so much sense.

Re: Robowranglers 2014: Vader
 

Could you expand a bit more on why the hard-connected version didn't work and why the center wheel must be articulated? It seems to me if you just had it dropped enough the hard-connection would work.

Re: Robowranglers 2014: Vader
 

I meant why as in why do this method over, lets say, spring loading it. I understand with H drive you want to have the center wheel always against the ground, however, my team's FTC team did an h drive with the center wheel drop a 1/16 of an inch and it worked pretty well. I am just curious about why use a "floating" center module rather than a spring loaded module? Was the reasoning so they could drift when the center motors were not running?

Re: Robowranglers 2014: Vader
 

Abishek,

It's impossible to have all the wheels touch the floor at the same time, because the floor isn't perfectly flat. As a result, there are times where a non-articulated center wheel will be lifting one side of the drive train off the floor, so that you end up going in circles when you try to drive forward.

I can't see the mechanism well, but I wonder if it doesn't use torsion springs to return it to level so it isn't touching the floor when it isn't running.

Electronica1: I'd venture a guess that your drifting hypothesis is correct. They've seemed to enjoy drifting - I remember them doing it quite a bit in 2011.

Re: Robowranglers 2014: Vader
 

Someone needs to let disney know that this robot will be in their movie. Not a question, a statement!:p

Re: Robowranglers 2014: Vader
 

If you are putting weight on a wheel that is not driving (Ie an omni wheel pointed sideways) that is weight that is not being put on the wheels that are driving. friction=coefficient*Normal, so the more weight on the HT wheels, the more traction, and thus the more pushing power.

While the /H/ leg of the drivetrain is not being run, those wheels are entirely off of the ground, thus they are not detracting from the weight on the traction wheels.

Re: Robowranglers 2014: Vader
 

Great job on the Robot and Video release!
I guess I'm late to the party.