Universal/Standard Drive Base

[Chris is me]

Originally Posted by kevinhorn

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.

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.

[Radical Pi]

Originally Posted by Chris is me

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.

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

[Daniel_LaFleur]

Originally Posted by Chris is me

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.

Originally Posted by 2010 rules

<R25> Prior to the Kick-off: Before the formal start of the Robot Build Season, teams are encouraged to think as much as they please about their ROBOTS. They may develop prototypes, create proof-of-concept models, and conduct design exercises. Teams may gather all the raw stock materials and COTS COMPONENTS they want. But absolutely no final design, fabrication, or assembly of any elements intended for the final ROBOT is permitted prior to the Kick-off presentation.
*Example: The same TEAM realizes that the transmission designed and built in the fall perfectly fits their need for a transmission to drive the ROBOT arm. They build an exact copy of the transmission from the original design plans, and bolt it to the ROBOT. This would be prohibited, as the transmission – although fabricated during the competition season – was built from detailed designs developed prior to kick-off.
*Example: A different team develops a similar solution during the fall, and plans to use the developed software on their competition ROBOT. After completing the software, they post it in a generally accessible public forum and make the code available to all teams. Because they have made their software generally available, under the terms of Rule <R67> it is considered COTS software and they can use it on their ROBOT.

<R34> Parts custom-made for FIRST and provided to FRC teams in the Kit Of Parts for previous FRC competitions (e.g. 2006 FRC transmissions, custom-made motor couplers, custom sensor strips, FRC CMUcam II modules, etc.) may be used if the part is still functionally equivalent to the original condition and:
A. The part is now generally available as a COTS item from an accessible source, or
B. All information required to fabricate the part (e.g. complete drawings, materials list, Gerber Files where appropriate, etc.) is openly available, such that any team could fabricate the part (or have it fabricated for them).
Otherwise, such parts are prohibited from use in the 2010 competition.

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.

[ajlapp]

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.

[Jon Stratis]

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.

[ttldomination]

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

[sdcantrell56]

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.

[Wayne TenBrink]

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.

[kevinhorn]

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!

[Chris is me]

Originally Posted by Daniel_LaFleur

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.

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

Originally Posted by kevinhorn

Considering different materials is a great idea. As a robot inspector I savor every non Al frame!

You've gotta inspect in Wisconsin then.

[artdutra04]

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

[,4lex S.]

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).

[kevinhorn]

Originally Posted by Chris is me

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

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.

Originally Posted by Chris is me

You've gotta inspect in Wisconsin then.

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