6 Wheel Drives Without Dropped Centers

[mman1506]

Originally Posted by cmrnpizzo14

Does anyone know if versa wheels would work for this sort of drive train? They have really good traction going forward and backwards but not the best laterally because of the W tread on them. I think that this sort of wheel would almost be perfect for this scenario.

Someone on CD said versawheels tend to dig in to the carpet like cleats when pushed laterally

[cmrnpizzo14]

Originally Posted by mman1506

Someone on CD said versawheels tend to dig in to the carpet like cleats when pushed laterally

I heard other wise from the highest traction wheels thread:

Originally Posted by T^2

They have good grip in the forward axis due to the "W" pattern, but horrendous grip in the sideways axis. This was confirmed for experimentally for us at Championships. (It wasn't our robot, mind you.)

Originally Posted by cmrnpizzo14

I heard other wise from the highest traction wheels thread:

What T^2 said is true given your robot remains completely flat on the floor, parallel with the carpet, and doesn't weigh too much. In the event you're not parallel (ie. being pushed from the side and slightly tipped upwards on the pushing end), the W tread will grip to the carpet like cleats. It won't need to be a significant lift, but anything to change the robot from parallel with the floor will engage cleat mode.

Source: Experience with cleat mode this year.

[coalhot]

Quite interesting, Miss Daisy used the VersaWheels this year, and I witnessed them getting pushed sideways. However, I'm not certain if they dropped the center wheel or not (6wd, 6cim), It would be interesting to hear about their drivetrain.

[Travis Hoffman]

48 has been running no drop center, 6WD West Coast setups since 2011.

2011: two 4" omnis up front, four 4" performance wheels in rear, roughtop tread. Long wheelbase.

2012: six 8" AM pneumatics, square footprint

2013: six 6" dia. 1" wide aluminum performance wheels, blue nitrile roughtop tread. Very slightly wide-biased footprint.

All three were powered by some variation of the A-M SuperShifter, 2 CIM's per side.

2012 was not surprisingly the least-maneuverable of the three setups, but it still was good enough to get the job done in one of our most productive seasons ever.

The 2013 iteration is very nimble yet able to provide enough punch to apply solid defensive pressure when needed.

[M. Mellott]

Originally Posted by Travis Hoffman

48 has been running no drop center, 6WD West Coast setups since 2011.

2011: two 4" omnis up front, four 4" performance wheels in rear, roughtop tread. Long wheelbase.

2012: six 8" AM pneumatics, square footprint

2013: six 6" dia. 1" wide aluminum performance wheels, blue nitrile roughtop tread. Very slightly wide-biased footprint.

All three were powered by some variation of the A-M SuperShifter, 2 CIM's per side.

2012 was not surprisingly the least-maneuverable of the three setups, but it still was good enough to get the job done in one of our most productive seasons ever.

The 2013 iteration is very nimble yet able to provide enough punch to apply solid defensive pressure when needed.

Just to clarify for Travis, 48's 2013 drivetrain ran 6-in custom performance wheels with 1-in roughtop tread riveted in place. Due to our relatively square frame, this put our wheel base at 24" between centers (front to back) and about 26.5"-27" between the center tread contacts side to side. It was an all-around quick cycle runner with no problems doing zero-radius turns in either low or high gears.

Our 2012 robot's wheelbase was only an inch wider than it was long, so with the much larger contact patches of the pneumatic tires, it definitely did not turn as well as this year's bot (as mentioned above).

[Jared Russell]

Originally Posted by coalhot

Quite interesting, Miss Daisy used the VersaWheels this year, and I witnessed them getting pushed sideways. However, I'm not certain if they dropped the center wheel or not (6wd, 6cim), It would be interesting to hear about their drivetrain.

We had 8 wheel drive with the middle 4 axles 3/32" lower than the outside axles (approximately 26.5" long x 29" wide frame). Note that because of our center of gravity, the rear 6 wheels (and in particular, the 3rd pair from the front) bore most of the load, and wore the fastest. As a result, at various points in the season we had 3/32" +/- 1/8" of effective drop.

It turned like butter (if anything, a little more scrub would have been nice), and it was possible for a high traction robot to push us sideways a little bit. But with fresh-ish wheels our traction in the forward/backward direction was incredible (we inadvertently tore a couple holes in the carpet at the Las Vegas Regional during pushing contests).

[coalhot]

Originally Posted by Jared341

We had 8 wheel drive with the middle 4 axles 3/32" lower than the outside axles (approximately 26.5" long x 29" wide frame). Note that because of our center of gravity, the rear 6 wheels (and in particular, the 3rd pair from the front) bore most of the load, and wore the fastest. As a result, at various points in the season we had 3/32" +/- 1/8" of effective drop.

It turned like butter (if anything, a little more scrub would have been nice), and it was possible for a high traction robot to push us sideways a little bit. But with fresh-ish wheels our traction in the forward/backward direction was incredible (we inadvertently tore a couple holes in the carpet at the Las Vegas Regional during pushing contests).

Ah, thanks for the clarification on the drive. I didn't have too much of a chance to look closely at the robot this season.

Is 8WD a new drivetrain standard with you guys? Just wondering...

[Ether]

Originally Posted by Jared341

tore a couple holes in the carpet

It will be interesting to see what the rules have to say about those wheels in 2014.

[Jared Russell]

Originally Posted by Ether

It will be interesting to see what the rules have to say about those wheels in 2014.

I have also seen roughtop tread tear a hole all the way through the carpet in a similar fashion (1676 attempting to push their whole alliance up a bridge at Brunswick Eruption). In both cases it was a pretty anomalous situation. In our specific case, we were slot loading because our ground loader wasn't working, and the driver didn't realize he was still holding down the sticks when we were against the wall.

[Ether]

So what immediate and post-event remedial action, if any, is taken when a bot tears a hole in the playing surface?

[Gregor]

Originally Posted by Ether

So what immediate and post-event remedial action, if any, is taken when a bot tears a hole in the playing surface?

Black Gaffers tape, lots of it. 2809 got stuck under the pyramid at GTRE, and kept spinning their wheels. They left us 4 nice holes to tape up.

[Ether]

Originally Posted by Gregor

Black Gaffers tape, lots of it.

What about post-event. Any attempt at a more elaborate repair?

[Gregor]

Originally Posted by Ether

What about post-event. Any attempt at a more elaborate repair?

Carpets are not reused event to event. Most are given away to teams.

[AllenGregoryIV]

Originally Posted by Ether

So what immediate and post-event remedial action, if any, is taken when a bot tears a hole in the playing surface?

We tore a few holes at Bayou this year. Lots of gaffers tape is the only fix. The FTA will also normally have a nice talking to with the team telling them to stop damaging their field. (Sorry Eddie)