Thoughts on the new AM14U 2014 KOP Drive train?

[Maximillian]

I am a part of a rookie team and we are trying to decide on a drive train. We think we decided to go with a drive system powered by the VEX Pro 2 CIM Ball Sifters. We thought that we had decided on using the VersaChassis but now with this new kitbot we are a bit lost. Does anyone have an opinion on the new Kitbot? I know that may be hard because its so new and the veteran teams may not have gotten one.

What about the VersaChassis? Do you think its a good drive train? It may be a good choice because you can make it a more custom size which could be useful for this year with the big game piece.

[Dad1279]

Originally Posted by Maximillian

I am a part of a rookie team and we are trying to decide on a drive train. We think we decided to go with a drive system powered by the VEX Pro 2 CIM Ball Sifters. We thought that we had decided on using the VersaChassis but now with this new kitbot we are a bit lost. Does anyone have an opinion on the new Kitbot? I know that may be hard because its so new and the veteran teams may not have gotten one.

What about the VersaChassis? Do you think its a good drive train? It may be a good choice because you can make it a more custom size which could be useful for this year with the big game piece.

I like the AM14U, kind of sorry we didn't opt for it. You can build it as is, wide or long. It also looks like it would be possible to build 30" x 26" square, which may be a good option for some teams this year. For a rookie team, I'd strongly recommend getting a moving drivetrain running as soon as possible, and using the extra time to practice.

[Ether]

Originally Posted by Dad1279

..30" x 30" square ... may be a good option for some teams this year...

What about Rule 4.1.3.R3A ?

[Richard Wallace]

Originally Posted by Ether

What about Rule 4.1.3.R3A ?

Pretty sure Dad 1279 meant "a little smaller than" a 30 inch square. Clearly 120 > 112.

By cutting the kit chassis rails on one end only, you can get a 27.5" x 27.5" square with 131 tooth belts on the short end and 170 tooth belts on the other end. About 9 inches wheelbase one way and 12 inches the other, with about 22 inch track. Should turn nicely, and the chassis is larger than the ball.

[Tom Line]

We really like the new AM drivetrain - so much so that after 7 years of building custom drivetrains we're strongly considering using it ourselves. We build out of aluminum stick and channel because we currently don't have any sheet metal capability (though we're desperately trying to figure out how to get it!). Because this is sheetmetal, it saves a substantial amount of space over a thicker 'tube' chassis. It's also much stiffer in a couple directions that the chassis' we normally build.

It can be modified to different sizes per the instructions in the manual.

Don't get me wrong though - ALL the chassis supplied by the different FIRST vendors are excellent options. Each for it's own reason. Something interesting to note with the AM chassis is that the wide version doesn't have a drop center wheel. I haven't measured the long one yet, though I'll do so today.

[valeriemoore]

As a rookie team, I would suggest getting your drive base built asap, so you can focus on other parts of your robot. The new kit bot seams like a good option.

[Dad1279]

Originally Posted by Ether

What about Rule 4.1.3.R3A ?

My bad, thank you.

[Shu]

We have also always done a custom welded alumiinum tube chassis and are seriously considering the AM14U this year. The main advantage I see is that we will save a week or so from our timeline by not fabricating it ourselves. This will allow us to spend more time on manipulators and practice time at the end.

[Tem1514 Mentor]

We put over 11 of the KOP drive together at a rookie quick build.
The new drive is 6 wheel drop centre and maybe configured in either a long or wide format. The mini tough box in also a low as is go without touching the ground so it makes for a very low CG. The two end tubs give you lots of room for all the electronics. Really nice design and a lot lighter that years before.

[Lil' Lavery]

Really frustrated that FIRST chose not to reveal this drivetrain before we had to chose whether or not to get the PDV. Would have absolutely chosen this if we had known ahead of time. But we were given the choice between $450 to spend on known solutions and what was essentially a mystery, so we opted for the PDV.

[Richard Wallace]

Originally Posted by Lil' Lavery

... we were given the choice between $450 to spend on known solutions and what was essentially a mystery, ...

Not essentially a mystery. We were told what type of drivetrain it would be, who would be designing it, and what the fundamental components would be.

[edit]@Tom: The square configuration is also a drop center.[/edit]

[Tom Line]

Originally Posted by Richard Wallace

Not essentially a mystery. We were told what type of drivetrain it would be, who would be designing it, and what the fundamental components would be.

[edit]@Tom: The square configuration is also a drop center.[/edit]

Richard, I haven't pulled the system out of the box, but I just rechecked the step file I have on reference and it shows the dimensions of the drops to be the same. Does someone have the system handy in the wide configuration so they can measure it? Someone else in this thread also checked the step and it shows no drop, and my box is at school and not at Ford where I can check it easily. -see post 23 supporting my dimension checks.

[TD78]

Originally Posted by Tom Line

Richard, I haven't pulled the system out of the box, but I just rechecked the step file I have on reference and it shows the dimensions of the drops to be the same. Does someone have the system handy in the wide configuration so they can measure it? Someone else in this thread also checked the step and it shows no drop, and my box is at school and not at Ford where I can check it easily. -see post 23 supporting my dimension checks.

I also found there to be no drop in the wide configuration (using the manual and STEP file). I am using the axle hole that is 8.762" from the bearing hole. I should have taken the shorter belt and laid it over the holes to verify...will have to do that later this week unless someone else here can verify first. I'm looking to modify the inner and outer plates to get close to square (28" wide and 27.5" length). I had to add new holes for mounting the inner plate to the cross brace. I also had to add new holes for 2 churros in each corner (so there would be 8 per side). I'm thinking of using VEX tube axle and 4" 1/4"-20 bolts instead of the churros...and changing to #10-32 bolts with the pulleys and wheels (I did this last year and it worked well). Don't think I can get away from using the thread forming screws though when mounting the inner plate to the cross brace...the extruded hole is just too big to properly tap for a 1/4"-20. I'll add in some Loctite if I do end up using them in the aluminum. If anyone has a suggestion on an alternative mount solution, would appreciate it. The wheel base is a little shorter than I would have designed for if making from scratch, but it doesn't seem terrible.

[Jon Stratis]

Does anyone know how easy it is to do a mecanum setup with this chassis? My first impression is that a 6-wheel setup is easy, but mecanum might be difficult...

[Richard Wallace]

Originally Posted by Tom Line

Richard, I haven't pulled the system out of the box, but I just rechecked the step file I have on reference and it shows the dimensions of the drops to be the same. Does someone have the system handy in the wide configuration so they can measure it? Someone else in this thread also checked the step and it shows no drop, and my box is at school and not at Ford where I can check it easily. -see post 23 supporting my dimension checks.

Sorry for my confusing post earlier, Tom.

The square configuration I was suggesting is not symmetrical fore-and-aft. I was thinking to get a (nearly) square chassis by cutting the side rails 2567 and 2572 on one end only. The resulting configuration has two wheelbases; one about 8.76 inch from the center wheel via the 131 tooth belt, and the other about 12.6 inch from the center wheel via the 170 tooth belt. Axle holes for the shorter span are at the same rail level as the center wheel (no drop), and those for the longer span are raised about 1/8" -- the result is a chassis that can tip just a bit on the center wheels, effectively a slight drop.