Drive Trains & All that they encompass

[ksafin]

Hello all.

I think most teams recognize that no robot is good without a decent drivetrain. We even had the mistake last year of working on our entire shooting and picking up mechanism only to find out 3 days from packing day that the robot was incapable of moving because the drivetrain was so horrendous.

I've read many threads about various drivetrains, I've done a good deal of research, but I would really like to spawn a comprehensive discussion about several aspects of drivetrains, what makes them good, when to use what, etc.

A few personal points I would like addressed:
(It's not vital that you address every single one, but these are some things I would love to hear answered for the benefit of knowing more about drivetrains as a whole)

1) What wheels do you prefer
1a) What kind of challenge/obstacle prompts a certain wheel choice
1b) What kind of wheel would you use if you had a low budget (aka can't afford $1,000+ on swerves)
1c) How do you personally choose what size wheel you prefer?

2) What do you make your drive train out of? (Base train, custom, 80/20, etc)

3) What gearboxes do you use for your motors, and why?
3a) Do you use shifters? Why?

4) What kind of wheel setup do you choose? (4 wheels, 6 w/ 2 dropped, etc etc)

5) How much time do you normally spend building your drivetrain?

6) Do you prefer to use belt or chain? Why?
6a) What would prompt using one over another?

7) Generally, long robot, wide robot, or it depends on the game?

[MichaelBick]

1) What wheels do you prefer

We are going colsons for this next year, because they are less work. I recomend this if you do not have a lot of resources(people, sponsors, tools). If you have the resources I really like AM performance wheels or custom aluminum wheels.

1a) What kind of challenge/obstacle prompts a certain wheel choice

Resources and game.

1b) What kind of wheel would you use if you had a low budget (aka can't afford $1,000+ on swerves)

Colsons with WCP hubs.

1c) How do you personally choose what size wheel you prefer?

Game dependent, but the smaller the better.

2) What do you make your drive train out of? (Base train, custom, 80/20, etc)

Custom

3) What gearboxes do you use for your motors, and why?

We will either be going custom shifting gearboxes or AM supershifters for this next year.

3a) Do you use shifters? Why?

Yes. They allow us to play defense(good for alliance picking), get past offense, gear faster, and are useful for getting over obstacles.

4) What kind of wheel setup do you choose? (4 wheels, 6 w/ 2 dropped, etc etc)

6 with 2 dropped in general. Depending on the game we could go 8wd with center 4 dropped.

5) How much time do you normally spend building your drivetrain?

It took us a long time last year because we went the stupid route and did not prototype a WCD(the drive we went with last year) in the offseason. If you do it right it should take your the first 2-3 weeks if you are going custom, 1 week if you are using the KOP.

6) Do you prefer to use belt or chain? Why?

Chain because we have worked with it before, it is forgiving, and it is reliable.

6a) What would prompt using one over another?

You should use chain unless you have lot's of resources and/or have prototyped it over the offseason.

7) Generally, long robot, wide robot, or it depends on the game?

Depends on the game, but we default to long because it is easier to weave between robots.

[Littleboy]

http://recordings.talkshoe.com/TC-98466/TS-681568.mp3
That is a recording of a recent EWCP cast about drivetrains.

There is probably many threads if you would do a search on it.

That probably covers most topics.

[Andrew Schreiber]

Originally Posted by Littleboy

http://recordings.talkshoe.com/TC-98466/TS-681568.mp3
That is a recording of a recent EWCP cast about drivetrains.

There is probably many threads if you would do a search on it.

That probably covers most topics.

Actually, that is the second cast on drive trains we did. It focused on skid steer systems. We have a previous one that is more general - http://recordings.talkshoe.com/TC-98466/TS-563546.mp3


Our full list of casts is available at http://www.talkshoe.com/talkshoe/web...d=98466&cmd=tc or in iTunes at https://itunes.apple.com/us/podcast/...477122221?mt=2

[ksafin]

I think somebody mentioned that many teams use Mecanum's or Swerve's (or at least explore these wheels) for the experience and knowledge of what these wheels offer, as well the advantages, disadvantages, and challenges of using them.

Part of why I brought this thread up is because next season by team was touching on the possibility of using Mecanum wheels. Now, if the game turns out to be something where Mecanum's would be a horrible choice, we obviously wouldn't use them. But if the game lends itself to Mecanum's decently, we were hoping to invest in some and hook them up.

Barring any complications you could foresee us having, does it make sense, in your opinion, for us to explore other options of wheels for our drivetrain? As much as you all agree that a standard drivetrain w/ 6 wheels like the kitbot or KoS is the best, I would still think that any team should explore different wheels, drivetrains, etc.

For some reason having a team that uses the same drivetrain for their entire career seems a bit shaking to me, as it takes away that aspect of Engineering in which we explore other possibilities, options, and then assess what we thought was best and how we move forward.

In essence, given what I've said, would you think it's ok for us to use Mecanum's next season if the game allows, and why or why not?

[MichaelBick]

Use the offseason to experiment, not the season. If you haven't tried mecanums yet then you shouldn, use it during the season.

[BJC]

Originally Posted by ksafin

I think somebody mentioned that many teams use Mecanum's or Swerve's (or at least explore these wheels) for the experience and knowledge of what these wheels offer, as well the advantages, disadvantages, and challenges of using them.

Part of why I brought this thread up is because next season by team was touching on the possibility of using Mecanum wheels. Now, if the game turns out to be something where Mecanum's would be a horrible choice, we obviously wouldn't use them. But if the game lends itself to Mecanum's decently, we were hoping to invest in some and hook them up.

Barring any complications you could foresee us having, does it make sense, in your opinion, for us to explore other options of wheels for our drivetrain? As much as you all agree that a standard drivetrain w/ 6 wheels like the kitbot or KoS is the best, I would still think that any team should explore different wheels, drivetrains, etc.

For some reason having a team that uses the same drivetrain for their entire career seems a bit shaking to me, as it takes away that aspect of Engineering in which we explore other possibilities, options, and then assess what we thought was best and how we move forward.

In essence, given what I've said, would you think it's ok for us to use Mecanum's next season if the game allows, and why or why not?

Hey there,

First off, I should warn you, I am a mecanum hater. My team will never use them in a drivetrain in the forseeable future.

You say that everyone says that a 6wd or 8wd is best. You also say that you are looking to explore different wheels, drivetrains, etc.

It sounds to me like you want to do some offseason testing. Mec wheels are expensive, however, they are off the shelf and if you bought them in the offseason you would still be able to use them in season if you didn't modify them. Now I'm not going to tell you not to use them, but it is always a good idea to test things new to your team in the offseason. If you test them out and decide you like them better, THEN you can make an informed decision on weither or not you should use them in the new game after kickoff.

The drivetrain is the most important part of any robot. It's not a good place to try new things without testing first.

Regards, Bryan

[AlecMataloni]

Originally Posted by ksafin

I think somebody mentioned that many teams use Mecanum's or Swerve's (or at least explore these wheels)

I would stay away from a swerve drive until your team has:
1. The resources to fabricate one (or purchase one. See team 221).
2. The capability to program one (often the hardest aspect of developing a swerve).
3. Experience with the drivetrain gained by making and programming one during the off-season.

[rcmolloy]

Originally Posted by AlecMataloni

I would stay away from a swerve drive until your team has
1. the resources to fabricate one (or purchase one. See team 221).
2. The capability to program one (often the hardest aspect of developing a swerve)
3. experience with the drivetrain gained by making and programming one during the off-season.

I agree 100% with what Alec says here. Even more so, the complexity of a swerve is a risk in itself. Encore was a machine that required maintenance almost after every match and we believe that the time that's spent fixing those components are more beneficial somewhere else.

The functionality of a Swerve is incredible but I still believe a team can never go wrong with a 6/8 wheel drive at all.

[MichaelBick]

Originally Posted by rcmolloy

The functionality of a Swerve is incredible but I still believe a team can never go wrong with a 6/8 wheel drive at all.

I agree with Cory here but I want to add that it's not only about if you CAN fabricate a swerve but also how quicly. I like to think of week 4 as the perfect time to have your robot (or at least your practice robot) completely built. Then you have two weeks to modify, program, and practice. If swerve is going to prevent you from getting a robot built before this time then you shouldn't be going with a swerve drive.

[ksafin]

Just to clarify guys, I never said we were going to pursue Swerve.

I'm aware of the difficulties and challenges of using Swerve, and pretty much ruled it out for those reasons. Besides, we're a year 2 team, Swerve is way out in the future for us, if it exists at all.

I was merely citing it as an example of alternate drive systems that teams explore versus traditional, simple drive trains.

[Billfred]

1) What wheels do you prefer After experience with the HiGrip wheels AndyMark puts in the kit, we're inclined to keep using them!
1a) What kind of challenge/obstacle prompts a certain wheel choice A specific need for some size or traction property. If it were a game that required every last bit of traction, we may go back to roughtop tread. If we had another game like Breakaway with a lot of really hard whacks, we may go pneumatic.
1b) What kind of wheel would you use if you had a low budget (aka can't afford $1,000+ on swerves)The AndyMark HiGrip wheels. They're in the kit!
1c) How do you personally choose what size wheel you prefer? Depends on the kit's offerings, desired speed, and the obstacles on the field. Cost is also a factor--if a 6" wheel is in the kit and gets us in our speed range, we're not going to drop big money on 4" wheels.

2) What do you make your drive train out of? (Base train, custom, 80/20, etc) Three of our four drivetrains are C-Base derivatives (we never quite build them to spec). Our 2010 robot was totally custom on the frame, but our expertise there graduated.

3) What gearboxes do you use for your motors, and why? We've used the AndyMark CIMple Box the past two seasons (and the Toughbox in 2009, but that was Lunacy and doesn't usually count).
3a) Do you use shifters? Why? We used shifters on 1618 a couple of times, and in 2010 (which, in hindsight, was a touch overkill). Recent years haven't made their necessity as obvious.

4) What kind of wheel setup do you choose? (4 wheels, 6 w/ 2 dropped, etc etc) All years except 2009 (again, Lunacy), we used a 6WD with dropped center.

5) How much time do you normally spend building your drivetrain?We normally get it together in a week or less mechanically. Electrical, programming, and other systems may influence when we turn it on and drive around.

6) Do you prefer to use belt or chain? Why? Chain every single year. Belt requires a lot more precision of fabrication, sometimes more than we have, and it makes it trickier to adjust gearing if we need it.
6a) What would prompt using one over another? The only thing that may change us over is the coming switch in the kitbot. Even then, we may go chain if we don't like the speeds the kitbot offers.

7) Generally, long robot, wide robot, or it depends on the game? Depends on the game. When a ball intake is needed, generally wide. When it's an arm game, long. But there are no hard and fast rules, especially if the field offers some obstacle.

[ttldomination]

1) What wheels do you prefer

I suppose I'd like to have three wheels in my back pocket.
Roughtop - If the field is all carpet, bam.
HiGrip - If the field is part carpet and part slick surface (like this year), mix these with roughtops.
Pneumatic - If a game is especially rough on the DT, then perhaps Pneumo would be something to consider.

1a) What kind of challenge/obstacle prompts a certain wheel choice

Kind of went into with 1.

1b) What kind of wheel would you use if you had a low budget (aka can't afford $1,000+ on
swerves)

I'd go with HiGrip (AM KOP) or Plaction Roughtop. Either way, wheels can often be used and serve as a good investment.

1c) How do you personally choose what size wheel you prefer?

We try to stay in the 6" range, but this is very game related.

2) What do you make your drive train out of? (Base train, custom, 80/20, etc)

We're using 8020 but I can see that its days are numbered. Most likely we will see a shift from 8020 to tubing in the next couple of years, provided we gain the required resources.

3) What gearboxes do you use for your motors, and why?

Toughboxes, and probably going to Toughbox minis this year.

3a) Do you use shifters? Why?

I think shifters do not make or break a robot, and I don't think anyone on the team is willing to drop the money to purchase one. If we work up the courage/budget to build/buy one, then we'll consider it, but for now, no one seems into it.

4) What kind of wheel setup do you choose? (4 wheels, 6 w/ 2 dropped, etc etc)

I just moved onto a new team, and they've had a ride when it comes to wheels (mecanum, 6wd, etc.). However, I think we've settled on your average 6wd-8wd DT hoping that the game isn't anything terrible.

5) How much time do you normally spend building your drivetrain?

This depends on how prepared you are going into the season. A well prepared team (as I hope we can be) will often get it done in a week. Others (as my team has been in the past), might take upwards of 2-3 weeks to get done.

6) Do you prefer to use belt or chain? Why?

We use chain, however, I've heard that belting is better (more efficient). Up until now, there isn't a terribly easy way to do belting, at least a way that doesn't require some form of machining. However, with the inclusion of belts in the KOP, we'll have to see what kind of hardware AM offers.

6a) What would prompt using one over another?

I'd say that weight, belting profile, and available hardware. It all depends on if we like what we see coming from AM.

7) Generally, long robot, wide robot, or it depends on the game?

I'd say it depends on the game, but one method won't kill you. As Billfred said, anything that has to do with massive ball intake, wider is better, but I've seen long orientation teams roll with the best of them.

- Sunny G.

Originally Posted by ksafin

1)What kind of wheels do you prefer
1a) What kind of challenge/obstacle prompts a certain wheel choice
1b) What kind of wheel would you use if you had a low budget (aka can't afford $1,000+ on swerves)
1c) How do you personally choose what size wheel you prefer?

2) What do you make your drive train out of? (Base train, custom, 80/20, etc)

3) What gearboxes do you use for your motors, and why?
3a) Do you use shifters? Why?

4) What kind of wheel setup do you choose? (4 wheels, 6 w/ 2 dropped, etc etc)

5) How much time do you normally spend building your drivetrain?

6) Do you prefer to use belt or chain? Why?
6a) What would prompt using one over another?

7) Generally, long robot, wide robot, or it depends on the game?

1) I (as in me myself and I) prefer high grip wheels (Colsons are wonderful). Smallish wheels (4"/5"/6" wheels are preferable, so the bot has a low center of gravity.

1a) Bumps (like this year's game and 2010) are the only reason I see for larger wheels.

1b) I think any team (large budget or not) should use a standard 6 wheel drop center tank drive. As for the wheel, traction wheels (2012 KoP wheels, treaded wheels, colsons) are the best economically, and usually the best performance wise. I'd say the 2012 KoP wheels are amazing for anyone, and a definite should-use for a low-resource team.

1c) I personally choose wheels based on my team's resources and our requirements. I suggest reading 1114's paper on drivetrains and wheels (http://www.simbotics.org/files/pdf/d...aindesign.pdf). I'm looking into Colsons, since they match my team's resources (middle) and requirements (high grip).

2) We make our drivetrain out of square steel tubing (.75" diameter, 1/16" thick wall), welded. However, steel is heavier than aluminum. It is stronger (one reason we use it), but we carefully plan out and control our weight so that our drivetrain is heavier, giving us a lower CoG, and the rest of our bot fits in the weight limit. I do not suggest this for a rookie/newer team.

3) AndyMark CIMple Boxes. I've got to say, those are some beautiful transmissions. I love them. They are small, light, cheap, come in the KoP (not in 2013), and allow for really nice driving speeds.

3a) We're yet to use shifters, however we only plan on using them when a strategy of ours requires a low gear (for example, pushing other bots up the bridge this year. No need for one in 2011).

4) For a long bot, we like the standard 6 wheel drive with the center wheel dropped 1/8", and our robots center of gravity between the middle and back wheels (better turning than directly in the center). This year we went wide, and did a 4 wheel drive. It was still pretty stable, but we designed with a really long wheelbase, which made turning a bit slow.

5) We design many different Drivetrains in the fall, so that by the time kickoff comes, and we have a general idea of what we want in a drivetrain, we'll have ideas to work off of. Designing a drivetrain shouldn't take any more than a day. If you have a smart design and know what to do, building a drive can be done easily in a few days (4-6).

6) While I hear belt is better in terms of efficiency, I personally will stick with #35 chain. I don't like designing drivetrains around the length of the belt. I'd rather be able to use chain and have it any length I want.

6a) I'd love to experiment with belt, but we've seen nothing wrong with chain, and have no reason to switch.

7) It all depends on the game. A wide bot was advantageous this year due to the bridge (and sometimes a wider ball pickup). My rule of thumb is this: If you need to fit in a specific dimension or pick something up using the wide side of the drive, go wide. Anything else, long.


I hope this helps. You should really look unto 1114's Kitbot on Steroids. It's one of the best drivetrains out there (top 95% of all drivetrains). http://www.simbotics.org/resources/kitbot Just because it's in the kit, doesn't mean it's bad. The kitbot was designed by engineers who know FRC. The KoS was designed by the team who has beaten those engineers.

[Gregor]

Originally Posted by SuperNerd256

3) AndyMark CIMple Boxes. I've got to say, those are some beautiful transmissions. I love them. They are small, light, cheap, come in the KoP (not in 2013), and allow for really nice driving speeds.

How do you know they aren't in the 2013 KOP?