Universal/Standard Drive Base
 

Soon team 2228 will be undertaking the task of reviewing all current drive bases to see the pros and cons of each and in the end come up with "the perfect" drive base so that we can speed up the design process of future years by having a pre-agreed upon drive base, that we feel can accomplish what we'll need for in any FIRST game. My question to everyone is are any other teams doing, thinking of doing or have done this in the past? If so do you have any advice on the matter? And also what is your opinion on whether this is a good move or not?

Re: Universal/Standard Drive Base
 

Personally, I don't really think that it is possible...

For instance (even though this was my first year in FRC), I know that many of the drivetrains we saw used in Breakaway would not be a good fit for lunacy, and vice versa.

Specifically, lets look at swerve drive. All the pictures I've seen of swerve drive from games that are not Breakaway, have very low ground clearance, like 221's drive (not sure what year this was though):


If a team wanted to use that in Breakaway, they would need to use the tunnels, but a drive like that also doesn't leave a lot of room for a kicker, or lifting mechanism. Thus, you make the robot bigger, which means it has to go over the bumps. But that frame won't let you go over the bumps, so you have to raise your ground clearance, a la team 2108:

Re: Universal/Standard Drive Base
 

If you'll use the handy-dandy search feature, you'll see that it's been tried, and fallen flat each time.

That being said, let me know if you make any real progress and I'll jump on board.

Re: Universal/Standard Drive Base
 

Please keep in mind that you will have to post your design on a CD like forum in order to use any design created outside of the build season. Good luck I look forward to considering your new design for our teams robot this coming season.

Re: Universal/Standard Drive Base
 

Since each game is different, the robot to play each game has to meet different requirements, so it's not real likely that there is such a thing as a universal drive base. If there were, it would probably not be optimized for any game.

How about coming up with half a dozen designs that are not quite finished, but can accommodate different game requirements? You can use past games for ideas for this. Of course, the real game next year will not be satisfied by any designs you come up with before then...says Mr. Murphy

Re: Universal/Standard Drive Base
 

Is this true? I've seen multiple designs based on concepts thought of during the off season this year that weren't posted on CD.

Re: Universal/Standard Drive Base
 

If parts are specifically designed during the off season it has to be posted. Concepts/unfinished parts are legal to keep to yourself if you modify them during the build season

Re: Universal/Standard Drive Base
 

Emphisis mine.

Also, be aware that the rules may change for next year ... but as of right now, no final designs can be created prior to kickoff.

Re: Universal/Standard Drive Base
 

Team RUSH (frc27) has used the same universal chassis concept since 2008.

The team has agreed that in order to work as efficiently as possible we will use the same standard chassis design and adapt the rest of the robot to work around it.

In my opinion, many of the most successful teams deploy similar strategies....though I don't know if they actually have an edict stating that they won't bother reviewing other ways to design or build their chassis like we do.

Our base chassis is a simple 6wd. It has no features or options other than wheel size and transmission style.

Re: Universal/Standard Drive Base
 

The idea of having a "standard" drive train you use year after year does have its benefits - you already have a rolling practice robot on day 1, you can get any needed parts for the drive train early and get a basic robot built quickly to start adding manipulators, and everyone knows exactly how it works.

But it also has some con's. As others have said, it probably won't be the "best" drive train for any given year - jack of all trades, master of none. But there's another huge con that you'll be depriving yourselves and future students of: The ability to design, build, and test a new drive train every year. Where's the fun in building the same thing every year? How much do you learn the third time you've built the same drive train?

We go in every year knowing the options for a drive train: 4 wheel, 6 wheel, omni, mecanum, crab, casters and traction wheels, something crazy. Over the past 4 years, we've done 6 wheel's twice, 4 wheels once, and mecanum once. And every year we have a valuable discussion with the students about what drive system to use, what the pro's and cons are, etc. Then the students get to work out the specifics of the design and build it. Yeah, it may take a little longer... but it's a valuable process.

Re: Universal/Standard Drive Base
 

I think that the teams who use the 6WD found it relatively easy to carry their dropped centers into the 8WD scheme. I think it's definitely possible to create a very *basic* layout, but don't let that stymie you from any possibilities in the build season.

- Sunny

Re: Universal/Standard Drive Base
 

We have pretty much used the same design the past 2 seasons albeit with improvements on manufacturability and maintenance each year and really even the 2 seasons before; however with different materials. It is awfully hard to argue against a well designed 6/8wd drivetrain particularly when taking into account time to manufacture/design/program. I am a firm believer in sticking with the basic skid steer drivetrain unless there is some never before seen drastic change next year.

THere is a lot to be said for having a general idea of the drive walking into the season and just being able to churn one out in the first week or so and devote all of your time towards perfecting a manipulator.

Re: Universal/Standard Drive Base
 

I don't know about that..........some would say that 254 has done ok since standardizing their drivetrain in 2004.

Re: Universal/Standard Drive Base
 

I, and anyone who knows anything about the Cheesy Poofs, would have to agree with this. While this year they may have had 8 wheels instead of the usual 6 typical of the "West-Coast Drive," there's nothing radically different from year to year from what I have seen.

While the chassis doesn't necessarily make or break a robot, I think there's something to be said about using a somewhat simpler design that's perhaps weaker in comparison to other designs, and instead using those resources, i.e. manpower and time, to focus on other challenges.

Re: Universal/Standard Drive Base
 

<threadjack>
I agree with your final conclusion that time can be spent elsewhere but NOT on the reasoning. A good drive train is critical to having a successful season. It will make or break your season.
</threadjack>

When doing your research for this SDB please consider multiple options rather than just copying 254. For example, weight the benefits and costs of sheet metal, fiberglass, wood, steel, welded tube, etc. Weight the benefits and costs of cantilevered wheels. Shifting vs One Speed. 6wd, 8wd, 10wd, 14wd. Also, share your research. Publish a white paper on why you chose one method over the other.

Re: Universal/Standard Drive Base
 

It was my interpretation that this would be a larger effort than a single team, and thus that it was similar to the "open source" bases that have been tried in the past.

Simply standardizing a style of drive base inside of a team is relatively simple and effective, and if that's the direction this is going, good luck and I hope the results for your team are as potent as others.

Re: Universal/Standard Drive Base
 

Instead of a single "universal/standard drive base" for all occasions, why not develop your own "drive base system" - along the lines of the Ansy Mark "C-Base" chassis in the KoP but better? The kit frame can be configured for long or wide chassis, 4WD or 6WD, different wheel size & type, etc. Regardless of the final configuration, it uses standardized frame rails & mounting hardware, motor mounts, axles, chain tensioning, etc.

We have been developing our own drive base "system" over the past few years. It doesn't look anything like the kit chassis, but it includes components that accomplish the same basic functions - and more. It has "standardized" structural elements, structural element fasteners, axles, gearbox mounts, chain tensioners & idlers, etc. It can be adapted for wide or long, various wheel arrangements (size & quantity), different ground clearance, "U" or rectangle (as viewed from above), etc. In the fall, we design and prototype improvemed components. After kickoff, we figure out what configuration we need for the game, lay out the detailed plan, and design new components if needed. It still requires some thought and takes time to build. However, it is faster than starting from scratch and frees up brain cells to concentrate on the manipulator. The parts are all based on proven concepts, and we have a lot more flexibility than we would with the kit chassis. We are usually cutting chips by the end of the first week and driving by the third week - long before the manipulator is done. So far, none of the components have been identical from year to year, but the improvements are becoming more "evolutionary" than they are "revolutionary".

There is nothing particularly special or ingenious about our "system". It is the product of our teams experience and efforts, and it works for us. Over time, I think most teams develop their own approach to the various bits of drive base hardware. I encourage you to approach your drive base design as a collection of "universal/standard components" that can be mixed, matched, and modified as needed, rather than a "universal/standard" assembly.

Re: Universal/Standard Drive Base
 

You have nothing to lose and lots to gain from this endeavor. The fact that more than one person has said that it cannot be done is good reason to try. You may find that they are right but you will still be better prepared for next season after an in-depth study of different drive systems.
Considering different materials is a great idea. As a robot inspector I savor every non Al frame!

Re: Universal/Standard Drive Base
 

Although we have used extremely similar drivebases each of the past seven years, we don't go into the build season restricting ourselves to just one style. Although the style of manufacture will probably stay the same (because that is what we can build easily), the drivetrain design could change drastically.

For example, in 2009, we spent weeks deliberating on whether to build a long or wide robot. Eventually, we decided on long not because it was what we had done before, but because we believed it allowed us to optimize our superstructure. In retrospect, that may have not been the right decision, but that is a debate for another day.

Re: Universal/Standard Drive Base
 

True, but the claim was that any design work done in the off season has to be posted.

You've gotta inspect in Wisconsin then. :)

Re: Universal/Standard Drive Base
 

"Plans are nothing. Planning is everything." -Dwight Eisenhower

Re: Universal/Standard Drive Base
 

For this to be successful, ensure you are smart about it. Develop what you think to be a solid all around drivetrain, but make it highly adaptable to whatever changes might be made.

So basically, what should happen assuming you have done the research, is a simple, robust 6-8WD system that will serve you well with a few simple modifications 95% of the time. Don't write this option off as too easy, I once made that mistake. Optimizing a 6-8WD is a very tough and entertaining challenge that I am sure could keep my engineering department at work pretty busy for a couple weeks.

My team agreed to do a simple skid steer in 2009, and we did. It worked well, but because we decided to do a wide robot base, it was a lot better than the original design would have been for Lunacy. If you are really enthused about an adaptable design, you could create an iAssembly in inventor that changes drastically to reflect different parameters you choose on creation (I have yet to try this, so I don't know how hard it is).

Re: Universal/Standard Drive Base
 

Daniel is pretty sharp! I don't think that he is contradicting the rules. Especially since he posted that great explanation of my claim that to use off season design work you must post it.
He may be saying that to select a design concept prior to knowing the configuration that best suits the game is unwise.

Two other things;
Design and concept are often used as if they are interchangeable.
I emphasize to my team that a concept is an idea maybe with some drawings.
A design is a set of documents that include: Key Performance Parameters, Drawings, a parts list, a budget and a timeline to finished product. Optimally this would also include calculations but this gets skipped more often than not.
You may call it what you like but being clear in your own mind when you have a design or merely a concept can be useful.

I am a big fan of 6 wheel skid steer But!... That has been done.
After dabbling in a copy of the AM 8" mecanums this year, I am eager to see more advanced drive platforms. Steering and suspension would be a great advance for many teams. Portland Jesuit came up with a really simple design for steering using a swivel on a Toughbox and steering with a globe.
Both front and back wheel sets could steer. That gave the team good steering and a limited ability to skew. This sort of simple but functional design is exciting because only a few teams have tried it and there is lots of room for innovation.



I would love to visit Wisconsin but Salt Lake is looking really cool and is closer.
Want to meet in the middle?