Ohh Well another trans down the tube
 

I had really hoped to the game would require monster power this year so we went ahead and worked on our next evolution of the shifter. Added the third motor and a servo shifter. However it is apparent that this will be overkill for this years game. It was, however, fun to design and build and it looks cool too!

Sadly I have to miss this entire build season due to a plant launch down here in Doraville. But hey I am already in Atlanta for the Championships!!

Re: Ohh Well another trans down the tube
 

Can you post some detailed specs or PM me about maybe some prints for this bad boy. I was given the task of finding ways to specifically link just the chalupa and the drills together. I know you have one more motor, but even that would be a start!

Re: Ohh Well another trans down the tube
 

same kinda thing happened to us. we were just wrapping up our "continuosly varible torque, velocity, and steering transmission" and now we gotta pick up balls. i say next year we have a FIRST drag race :D

Re: Ohh Well another trans down the tube
 

That is over kill, but try the technokats at www.technokats.org

Re: Ohh Well another trans down the tube
 

3 motors? Be carefull there, don't wanna draw too much power at once, theres a whole set of problems that come along with that.

Also, speed and power are both important for this game. There's always a pushing match somewhere...

And speed, oh man, now thats gonna be a large factor...

Re: Ohh Well another trans down the tube
 

Matt, that is an awesome design. Nice job.

I'm sure you know that not being able to realize the benefits of it this year is not much of a loss in the long run. You just added a great design to your "tech shelf".

Re: Ohh Well another trans down the tube
 

Matt,
It's a beauty. Too bad you're not going to use it.

We're in a similar boat, having designed and built a full 6-motor, techno-knockoff drive this fall. Like you, we decided it would be better to have a powerful design if we need it, and maybe "tone it down" a little, than be in need and have to start from scratch.

Obviously, we don't have a need for THAT much output power in this game (*gasp* Did I just say that?), and we're deciding what functionality to "cut" for our 2004 system. So many numbers to plug, so little time!

I am curious how the servo handles shifting. Any troubles with it? Any regrets?

Tough luck missing out on 2004. Hope you'll be back in ohh-five.

John

Re: Ohh Well another trans down the tube
 

That is one sick transmission. I know our team has always been trying to find some type of advanced transmission like that. I would really like it if you could send me some blueprints, or specs, or better yet put them in the white pages.

Re: Ohh Well another trans down the tube
 

Any time or effort spent in which you learn new things and develope new skills

is never wasted

you are hereby designated as your teams official Research and Developement Department :^)

Re: Ohh Well another trans down the tube
 

Good grief how much does that transmission weigh? like 40#? we built one using the CIM (or whatever it is again) we have a high speed low tourque and low speed high tourque. it uses the CIM, aorund 10 1/4 inch gears and a pneumatic cylinder somewhere around 3" long. it only weighed aroung 8 pounds or less?

Re: Ohh Well another trans down the tube
 

Your third motor would have been better off on you end effector anyways.

Re: Ohh Well another trans down the tube
 

Suprisingly light actually, the gears are all lightened, the crossmembers are aluminum alloy, the box itself is made of ballistic lexan 3/16". The Bosch mount is aluminum. The final version is see through and really nice looking. It would be tough to pack this much power in a much lighter package and still stay robust.

Re: Ohh Well another trans down the tube
 

What was the final weight of each?

Re: Ohh Well another trans down the tube
 

I know the feeling...
Just finished a two motor two speed...
*sigh*

-Andy

Re: Ohh Well another trans down the tube
 

It doesn't mean you've wasted your time, a two motor transmission will still be useful. There will always be some shoving and you'll still need to get from point a to point b fast.

Re: Ohh Well another trans down the tube
 

Two summers ago, my team (116) spent the summer developing a gearbox. It is a two motor, two speed gearbox with a weight of 10.0 lbs. We have posted documentation on it for other teams to use. This documentation includes blueprints, a parts list, 3D images, and other technical information. I will try to find where this is located, so that you may retrieve it at your convenience.

Re: Ohh Well another trans down the tube
 

Team 116's whitepage on our two-speed gearbox can be found here. Elgin, it couples the drill and chalupa together. It can also be made with just a mill and lathe.


Wetzel

Re: Ohh Well another trans down the tube
 

I'm not a physics major but I have designed and built a two motor two speed pneumatic shifting gearbox and competed with it in competition. I think the two motor system helps but I think it could be argued that that much power is wasted on a FIRST robot. with only 130 lbs of robot there is no way that you can transfer all that tourque to the ground. Your wheels will spin out before your motors will stall. I think using one motor per side and adding some sort of skirt or other mechanism to transfer the weight of another robot to the ground is the way to win the pushing match not adding more motors. what does everyone else think?

Re: Ohh Well another trans down the tube
 

last year a few teams build wedges to give them a protective and pushing advantage as you pointed out

problem was some bots didnt handle being 'lifted' a little and were tipped over in shoving matches - and tipping another bot will get you disqualified.

if you lift the side of the bot you are pushing against, all that does is transfer most of the weight to its rear wheels - they can still push back just as hard, but you have altered their center of gravity, and there is a good chance you will tip them.

Re: Ohh Well another trans down the tube
 

I don't think that having a multiple motor drivetrain is wasted power. Maybe if you are using 2 wheel drive or slippery wheels. However, we were using treads and our robot last year was quite fast for a first robot, and in high the motors would be at stall if it encountered a pushing match. With only 2 motors you are severly limiting the power of your drivetrain. As debated before more motors can give you the same torque at a higher speed.

Re: Ohh Well another trans down the tube
 

yeah.. we've had a 2motor (drill/atwood) 2 speed transmission for a few years now, and we've decided to use it again this year.. some of the engineers didnt think it would be necisary, but after a whole bunch of *debates* the 2 speed finally won out.. ive got pics of last years atteched if anyone is interested