Anyone use AM-2202 446 Drive Module?

[dsherw00d]

Hello,

We picked up a set of these (http://www.andymark.com/446-p/am-2202.htm) and have been looking at them for the 2013 season. I searched the site and don't find any referenced to teams using them. Does anyone use them for competition? From prototyping/mock up, it looks like the CIM motor keyways are not long enough and we see a few other issues related to component replacement and strength.

Anyone have any experience they can share?

Thanks,
Dan
Newfane Circuit Stompers

[Jorge Ayala]

Hi

My team built a prototype with that drive module yesterday. The first thing we noticed when the drive train was finished is that it was insanely heavy. There weren't any problems with the CIM motors keyways for us. Personally I am not very satisfied with the wheels. So far we have not been able to fully test the drive train prototype and we won't until next year. However during the Kick Off event here in Mexico we will be testing the drive train with other Mexican teams. If something interesting comes up I will let you know.

I am also very interested in knowing if someone else has some experience with the 446 Drive Module.

(Sorry if my English is not perfect, I am not a native speaker but I am doing my best)

[IanW]

I know Team 1540 used them in a preseason mini-competition. Their coach, Dale, frequents the forums and could probably connect you with the students who used them.

From casually observing them during matches, they seemed to work fine. The team did well, and either won the competition or was a finalist (1540 fielded four teams, so it is hard to remember which was which...)

[MattC9]

Originally Posted by IanW

I know Team 1540 used them in a preseason mini-competition. Their coach, Dale, frequents the forums and could probably connect you with the students who used them.

From casually observing them during matches, they seemed to work fine. The team did well, and either won the competition or was a finalist (1540 fielded four teams, so it is hard to remember which was which...)

Could you provide footage of these in action?

[Billfred]

Conceptually, it makes sense; it's the guts of an AM Shifter with different side plates and traction wheels. I saw AndyMark driving one around at IRI (I believe it was Brett driving), and it was moving around fast even on the slick floors.

But no, I haven't used it.

[Peyton Yeung]

I've driven one and it is very smooth. Tested on both carpet and shop floor and both seem to react well. It pushes well too, found that out when it ran into some metal shelves and almost knocked them over

Peyton

[Dale]

Yes, Team 1540 did use them for one of our robots in BunnyBots, 2012 a week ago. This is a FRC-style preseason competition we host here in Portland.

The robot in question was 1540 Bogie and was our most sophisticated of the four we fielded. Some observations about the 446 platform.

Pros
Weight. We found these much lighter than the equivalent frame we'd make from scratch. We have the weights on the white board back in the lab but I seem to recall the base with two CIMs being around 40lbs. That's for a two speed shifting transmission, eight wheel drive, chain, wheels, cross members, brackets, the whole nine yards. That's pretty good in my book.

Shifting seemed fine for our one day competition. The base was very fast in high gear yet could push with the best of them in low gear.

Eight wheel drive. That's game dependent whether it helps. It didn't make any difference for BunnyBots. Oddly it did high center in one match on a 3" high goal.

Gear driven main drive wheels. #25 Chains drive the secondary front and back wheels. That means a broken chain won't disable your robot.

Cons:
Because of the drive modules aren't square (they are angled front and back I guess to save weight) they are a pain to work with. Everything you mount to them needs to be cut with that ever-changing height in mind.

Balance. The frame really works best if the robot drives most of it's time on the middle four gear-driven 4" wheels. The front and back 6" wheels are there for when the CG shifts during acceleration, climbing, pushing, etc. That means you need to be really careful when building your robot to keep the weight in the center. Lots of fun was had by our team mounting the battery!

Only available in long configuration. If you need a wide robot for the game at hand look elsewhere.

Bottom line
We'll probably use them this season if the game calls for a long orientation robot. It's not a drive system for beginners due to the balance and angled mounting issues.

Sorry, no pictures right now.

[thefro526]

I saw a demo base built using the 446 a few months ago and I was definitely impressed with how well packaged everything seemed to be. Personally, my favorite feature is direct drive from the transmission to the center wheel couple, it really helps to make the drive essentially bullet proof. Otherwise, I the module lends itself to lower CG designs than a traditional 'transmission on top of rail' setup since the guts of the transmission can be moved down relative to the floor by about 2-3".

I did notice that the drive was a bit on the heavy side, but all things considered, it's not a bad place to hide some weight since it's down low. If you're really concerned about pulling a few pounds out, it's easy enough to swap out a few of the larger gears for their aluminum equivalents. Just swapping out the 2 56T Wheel and the 2 50T Idler Gears to Aluminum would net you a savings of 1.3lbs per module, or 2.6lbs per drive train. If you really wanted to keep pushing the weight down, it's possible to drop even another pound by replacing the shifting gears and initial cluster gears, but I don't think the expense is needed.

One minor tweak I would make if I were going to use this is to swap out all of the connections that hold the two module sides together from through bolts and spacers to a female x female standoff and a short bolt on either side. Same thing with the axles. I think this would make servicing the drive a bit easier, but that's just me...