Robowranglers 2014: Vader

[pfreivald]

Originally Posted by cmrnpizzo14

That play in general will be a lot more powerful than people were thinking at the beginning of the year. If you have a human player that is used to it, you can get easy truss points and you won't lose control of the ball.

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!

[bEdhEd]

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

[Duncan Macdonald]

Originally Posted by lineskier

I noticed a rangefinder on the front of the bot. Could that be an autocatch feature?

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

[AlecMataloni]

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.

[CalTran]

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

[MrRiedemanJACC]

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.

[chrisfl]

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

[Tom Line]

Originally Posted by Electronica1

I am thinking the same thing, but I am having issues see how they are getting enough force to give the wheel traction because won't most the weight still be on the 4 outer wheels?

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.

[PAR_WIG1350]

Originally Posted by Tom Line

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.

That makes so much sense.

[Abhishek R]

Originally Posted by Tom Line

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.

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.

[Electronica1]

Originally Posted by Tom Line

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.

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?

[Tom Line]

Originally Posted by Abhishek R

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.

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.

[Canon reeves]

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

[BBray_T1296]

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.

[waialua359]

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