FIRST provided transmissions survey

[FTtyler]

Do you think that it is better to use the transmissions that come in the FIRST kits or to design your own transmission?

Would you consider the transmission a problem worth reseaching?

Thanks for your opinions.

[Tottanka]

i think that it is always better to have your own custom made transmission. Both in matters of learning how to make one, and in having it better suite your robot.
The given transmissions are much better for rookies though, and teams who are not able to make their own.

[Stuart]

We always use the transmissions given. and will for the foreseeable feature(unless I get a call from our treasurer saying he landed us a 30k+ sponsor). now that being said we do use the transmissions in an arangement thats not well 'common".

as far as what is better . . . well while I do see the educational benefit of designing your own. you also get the same benefit for designing other parts of the robot(arms, manipulators, pneumatics). so I would say if you want to make a custom tranny go for it . . but if you dont I dont think your at any big loss, nore if you do are you at any great advantage.

[EricH]

For teams that design their own, they learn a lot about how to make these things work. Some teams, however, do not have the resources to do that. They may be rookies (in which case, I'd recommend the AndyMarks over the kit trannies) or they might be struggling in other matters. It's worth researching for anyone, but do it in the summer, when resources aren't as tied up.

Also, don't expect it to be quick and easy. In 2003, my team saw mecanum wheels for the first time while returning from Houston. It took us until 2005 to get a set at full scale for testing. We still haven't put them on any competition robot. (2005 was the closest. In Week 5, I think it was (might have been Week 6), we finished testing and concluded that we would go with a different drive system, but we'd allowed for both during build.) So, you not only have to design this cool gadget, but you have to convince a team that it will help them.

[Jherbie53]

It all depends on you how you want your transmission setup. It you want a two speed then build or order one. If you want to focus on another part of the robot without spending a lot of time on the drive train the go with the kit ones. Other factors are the type of drive train your using and the game that year. Some years you get a good kit transmission, while other years you can build a better one. It really varies from year to year, and team to team.

[Billfred]

The answer: It's complex.

You've got to figure out what the transmission supplies (in terms of weight, gear reduction, motors accepted, cost, ability to be mounted, size, reliability, potential for inspiration, etc.) and determine if that fits your desired strategy better than the other options available to you (such as ordering from AndyMark, using a design another team published, or rolling your own). The amount of weight you assign to each of those variables varies from team to team, as will the conclusions.

[AdamHeard]

We should build robots that play the game.

Look at what your winning strategy is for the particular game, and what it requires of your drivetrain. The layout of the field and the amount of defense you anticipate are the two biggest factors in your choice.

Many argue that you don't "need" shifters, others claim they need that high speed. In the end, whatever you pick, make sure it is reliable. If your drive fails, your robot fails.

Personally, I think the AM single speed and the AM super shifter should cover most situations. The AM single speed is superior to the Banebots in efficiency, weight, reliability and cost. The AM super shifter is pretty much the easiest to use shifter out there.... You just bolt it on, and it works!

IMO, even if the 56mm banebots is in the kit next year, don't use it... They can work, but there are far better options (I don't have a grudge against banebots either, I run there gearboxes almost exclusively in my combat robots).

EDIT: Pet Peeve; A single speed = Gearbox, Shifting = Transmission.

[ebarker]

Originally Posted by AdamHeard

EDIT: Pet Peeve; A single speed = Gearbox, Shifting = Transmission.

The term transmission goes back decades, maybe a century for mechanical gearboxes that perform speed/torque modification.

In the mechanical industry the term 'power transmission' covers all type of fixed variable speed gearboxes, chains, belts, couplers, shafts, pulleys, etc. It is a standard nomenclature that goes back a LONG way.

BTW, in the electric power industry 'power transmission' is the high voltage 64K to 500K lines that connect generation stations to the distribution grid, but that has nothing to do with this topic.

[AdamHeard]

Originally Posted by ebarker

The term transmission goes back decades, maybe a century for mechanical gearboxes that perform speed/torque modification.

In the mechanical industry the term 'power transmission' covers all type of fixed variable speed gearboxes, chains, belts, couplers, shafts, pulleys, etc. It is a standard nomenclature that goes back a LONG way.

BTW, in the electric power industry 'power transmission' is the high voltage 64K to 500K lines that connect generation stations to the distribution grid, but that has nothing to do with this topic.

If that is the case, there is a certain rather stubborn mentor on my team I need to talk to..... (I've been chewed out for using the term transmission to describe our single speed)...

[artdutra04]

Whereas the real estate industry has the term Location, Location, Location, we have Requirements, Requirements, Requirements.

There is no set solution that works every time, except careful thought and designing. Calculate out the needed requirements of the robot drive train, and check each these against existing solutions and/or building your own, and choose wisely.


// Although as a word of caution, even 56mm Banebots with hardened carrier plates and welded pins for the planetary gears, won't last more than two or three competitions. Now if your team doesn't attend more than this number of competitions per year, you can use the Banebots without problems. But if you attend multiple regionals, or have a busy off-season circuit, you'll most likely end up replacing the Banebots every 2-3 competitions. (Which in the end, can cost more than just buying AndyMark single speeds outright, not to mention the grief and frusteration...)

[AdamHeard]

Originally Posted by artdutra04

// Although as a word of caution, even 56mm Banebots with hardened carrier plates and welded pins for the planetary gears, won't last more than two or three competitions. Now if your team doesn't attend more than this number of competitions per year, you can use the Banebots without problems. But if you attend multiple regionals, or have a busy off-season circuit, you'll most likely end up replacing the Banebots every 2-3 competitions. (Which in the end, can cost more than just buying AndyMark single speeds outright, not to mention the grief and frusteration...)

Amen to that.

The Banebots 2 to 1 Adapter, or an additional gearbox per side already puts you in the price range of the AM single speeds. My as well just get them in the first place.

[MrForbes]

If you have the wherewithal to design and build your own transmissions (and still make the rest of the robot effective), then go for it! If you don't, but you do have the money to buy aftermarket transmissions, then that might be the best way to go. Otherwise make the best of the kit transmissions...but you might have to design around them, as they generally are a low cost design that will just meet the need.

A single speed gearbox is a transmission, and a multi-speed gearbox is a transmission too.

[=Martin=Taylor=]

Our team has done it all.

We've built our own, used the kit ones, used AM's, or bought pre-assembled gearboxes from other companies.

And guess what? It hasn't made a big difference! The success of our robots has depended more on the scoring mechanism than on the drivetrain.

IMO a good drivetrain is reliable, light, and gets the robot where it needs to go.

We used the AM shifters last year and they worked really well. Thats probably what we'll be sticking with.

[AndyB]

As much as most teams use non-KOP frames, transmissions, wheels, etc...

There is definitly an edge to having a moving chassis on day 1. For the actual competition though, we have always found that going with our own custom built stuff is the best option for the simple fact that you can create it to do SPECIFICALLY what you want it to do.

In the past I may have said differently with the KOP tranny's but after having a good year with our own tranny's, I'd have to argue towards building your own.

That being said, if your school is lacking machining equipment/sponsors, going with the AM Single Speed transmission, some KOP wheels, and the kit frame to do a simple 6wd is definitly a good way to go.

[Dan Petrovic]

Originally Posted by artdutra04

// Although as a word of caution, even 56mm Banebots with hardened carrier plates and welded pins for the planetary gears, won't last more than two or three competitions. Now if your team doesn't attend more than this number of competitions per year, you can use the Banebots without problems. But if you attend multiple regionals, or have a busy off-season circuit, you'll most likely end up replacing the Banebots every 2-3 competitions. (Which in the end, can cost more than just buying AndyMark single speeds outright, not to mention the grief and frusteration...)

We had our own carrier plates made that have lasted us since we put them in (about week 4 of build season). They've been through 2 regionals and 3 off-season events.

But if you have the capability to make those carrier plates (try cutting that double-D hole with a CNC) then you have the capability to make your own transmission.

Between the 2007 provided transmissions and designign your own, I'd definately say design your own. Those 56mm Banebots transmissions didn't cut it. The smaller ones worked great, we've been using them since build season throughout all of our competitions without problems.

2005 and 2006 kit transmissions were fantastic and I'd say go with them if you didn't decide that a shifting transmission was necessary. However, that's not an option anymore.

And everyone else has already said what needs to be said about buying transmissions.