2 Gear Drive Train

[AT man]

Is any team using a multi-geared drivetrain? If so what are some pros and cons.

[John Bono]

You must be joking. I suppose if one of those teams that can afford to live in a machine shop could do it, but there's not that good of a reason. Either you push or you zoom. Chances are your bot only has to do one of these during the match depending on its design. And I know our team isn't going to waste the valuable servo/pump to hook up the system.
For that matter, if you're asking that question this late, chances are you're pretty screwed.

[AT man]

Originally posted by John Bono
You must be joking. I suppose if one of those teams that can afford to live in a machine shop could do it, but there's not that good of a reason. Either you push or you zoom. Chances are your bot only has to do one of these during the match depending on its design. And I know our team isn't going to waste the valuable servo/pump to hook up the system.
For that matter, if you're asking that question this late, chances are you're pretty screwed.

Our team already has the two gears and they work beautifully. Thanks or the comment. I am just trying to see if anyone else tried it.

[Jeremy_Mc]

Originally posted by John Bono
You must be joking. I suppose if one of those teams that can afford to live in a machine shop could do it, but there's not that good of a reason. Either you push or you zoom. Chances are your bot only has to do one of these during the match depending on its design. And I know our team isn't going to waste the valuable servo/pump to hook up the system.
For that matter, if you're asking that question this late, chances are you're pretty screwed.

that was rather harsh....

you don't have to live in a machine shop to do it. you just need experienced machinists. we didn't do two gears, and we probably couldn't if we tried.

and it's definitely not too late to change to a two gear system.

until you hit the field, it's never too late.

*jeremy

[Cory]

you dont need to machine squat. use a servo and shift the drill motor. I dont know what else youd use it for that is better than shifting. PS shifting will be essentila this year, it is ALWAYS better to be able to go slow/torque, or fast

Cory

[John Bono]

Oh yeah--I suppose you could do that. But you'd have to be at a perfect stop and hope your gears come together jsut right.

[Ken Leung]

To a team without any experience making a servo shifter, it would seems impossible to do without a machine shop. However, many have learned that it take mearly a hand drill and a couple pieces of metal to make a successful one. All it take is simply looking at other's design, and trying to duplicate it.

Given a week of time, ANY team can make one work as long as they've seen it before.

If you want to hear what people have to say about shifting gears on drive train, take a look at this thread: http://www.chiefdelphi.com/forums/sh...threadid=16810

Having a speed shifter on your robot simply give you more freedom in the match. It is true that you may choose one speed during one match, but over all, there will be many different situations, and you may find yourself needing more torque, or more speed depending on what teams you are playing with. All it take is a few pounds, and a few days of work, with many things to gain.

[Cory]

Originally posted by John Bono
Oh yeah--I suppose you could do that. But you'd have to be at a perfect stop and hope your gears come together jsut right.

It is really ez actually just put in the program to not allow the shifting button to workl until the motors are at a complete stop. The gears will mesh automatically there really is no degree of precision when shifting with a servo

Cory

[Solace]

having a gear switching device is really easy (if you're using drill motors). we slapped one on our robot in less than an hour last year.

[Andy Baker]

Originally posted by John Bono
You must be joking. I suppose if one of those teams that can afford to live in a machine shop could do it, but there's not that good of a reason. Either you push or you zoom. Chances are your bot only has to do one of these during the match depending on its design. And I know our team isn't going to waste the valuable servo/pump to hook up the system.
For that matter, if you're asking that question this late, chances are you're pretty screwed.

Just so you know, you should check the white papers on this site.

There are a number of gear switching desings that are posted on there... from numerous teams. Our team has posted 3 separate designs (with all details included) that shows the design of a gear shifting system. 2 include shifting while stopping and 1 includes shifting while moving. We have published one design during each of the last 3 summers, and these designs have been downloaded thousands of times.

We've been shifting gears since '99 and we will be again this year.

Andy B.

[sevisehda]

Um I'm taking it your new to FIRST Bono. ALOT of the teams use multi-geared transmission. Some actuate the drills others build customs rigs like the X-Cats. I think someone even has a C.V.T.
The benefits are amazing. If you want to push you have to go slow, <3ft/s, but it would take you forever to get places like that, but being able to run >10ft/s would mean you'd be able to knocked out of the way easier than a box. Its a cylinder and 2 extra gears to shift not that much considering the benefits, cost/benefit wise its the best thing you could do in most cases.

[sevisehda]

I'm not sure if you meant to but you came off pretty bitter and angry. I think that AT Man was trying to start a discussion on why or why not to use a multi geared transmission. And theres still plenty of build time left, especailly considering people have built entire bots during the practice times before regionals.

2 Speed Gear Boxes...

Pros:
Versatile in the fact they can push and run.
If you can shift on the fly you can get better acceleration.
It looks really cool.
Teaches the team alot if its the first time you've tried it.

Cons:
Heavier than a 1 speed.
Have to use pnematics,servo,motor.
Complex to fix/build.
Larger space wise.

[John Bono]

I'm sorry, I was working on the assumption that the person asking was rather new (although this is my second year with first and I indeed have multi-gear drive trains). It just seems pointless unless you have a lot of shoving to do--and our team doesn't want to use the valuable space for the servo or piston, and it seems to me not many teams would have (we ALWAYS max out our pistons in any concept sketch). And servos just don't have a whole lot of umph to them.
Also, the real force you should be worried about is friction with this year's surfaces, I wouldn't expect you to be able to get a friction coefficient of more than .3 or so (I guess as high as .7 is possible if you're awesome cool), and the drill motors can put out more power than that on low if I recall (then again, I could be a ranting moron--chances of which are high).

[Cory]

Originally posted by John Bono
I'm sorry, I was working on the assumption that the person asking was rather new (although this is my second year with first and I indeed have multi-gear drive trains). It just seems pointless unless you have a lot of shoving to do--and our team doesn't want to use the valuable space for the servo or piston, and it seems to me not many teams would have (we ALWAYS max out our pistons in any concept sketch). And servos just don't have a whole lot of umph to them.
Also, the real force you should be worried about is friction with this year's surfaces, I wouldn't expect you to be able to get a friction coefficient of more than .3 or so (I guess as high as .7 is possible if you're awesome cool), and the drill motors can put out more power than that on low if I recall (then again, I could be a ranting moron--chances of which are high).

Umm yeah... I know teams that have a COF of >1

Cory

[John Bono]

Wait-wait. It takes more force to move thier robot than it weights? Thanks for breaking several laws of physics.