FIRST provided transmissions survey
 

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.

Re: FRIST provided transmissions survey
 

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.

Re: FRIST provided transmissions survey
 

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.

Re: FRIST provided transmissions survey
 

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.

Re: FRIST provided transmissions survey
 

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.

Re: FRIST provided transmissions survey
 

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.

Re: FRIST provided transmissions survey
 

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.

Re: FRIST provided transmissions survey
 

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.

Re: FRIST provided transmissions survey
 

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)...

Re: FRIST provided transmissions survey
 

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...)

Re: FRIST provided transmissions survey
 

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.

Re: FRIST provided transmissions survey
 

Way Way back in the day when I was probably your age I acquired a bookshelf of power transmission catalogs and datasheets. Somewhere I still have some of that, in a box in a barn I think. Morse Powertransmission catalogs and such.

Re: FIRST provided transmissions survey
 

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.

Re: FIRST provided transmissions survey
 

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.

Re: FIRST provided transmissions survey
 

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.

Re: FIRST provided transmissions survey
 

Our team has gone for designing our own transmissions for the last three years. The first was a Crab Drive, so we didn't really have a choice about using the kit tranny. The second was using the 3 inch CIM with belts attached, and was a 2 speed ball lock. The third was this year's 2 speed dog shifter, with 2 small CIMs.

I'd say that this year was our most successful year, and here's why: We spent a lot of time simplifying the game. We realized that you'd need to get tubes from A to B, and built the simplest possible system of doing so. We also realized that in order to maintain a competitive edge, we'd need the shifting capability.

As for the resource issues, here's my suggestion: The only drivetrain useable machine tool that 114 has is a Mill with a DRO. However, we end up with nice welded frame bots, with CNC'd drive systems, and very advanced parts. How do we do that? We go around to local shops, ask them if they can help us, either by cutting cost, or donating machine time. It's a bit of work, but in the end it pays off wonderfully.

Re: FIRST provided transmissions survey
 

By the way, the BaneBots transmissions this year (before the issues were resolved) were close to the worst ever, second only to the drill motor trannies used pre-2005 (if not worse). The 2005-2006 trannies were really good, and were almost exactly like the AM single-speed. (Hey, I'm biased--we won the championship with one set of KOP trannies that year.) This year, my team just used AM 2-speed pneumatic trannies. Our driver seemed to like them better than the single-speed ones, and the robot performed just as well.

However, I'll echo what others have said: it depends on the game whether or not your new tranny design is actually used. Suggestion: use an old robot/Kitbot, build a mockup with the new design, and put it through the mill before or after the season if at all possible. This will help determine what the tranny can and can't do. Then, figure out what you want the drive to do during the design time, and match a drivetrain to that.

Re: FRIST provided transmissions survey
 

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.

Re: FRIST provided transmissions survey
 

Indeed.... even if you can make the Banebots work for you, they're more inefficient and heavier than the AM single speeds.

One thing I forgot to mention earlier that I tell my team;
In the recent years robots are either playing defense, or being defended.
It's best to build a nice base that can play defense even if you plan on being an offensive robot because;
a) If you've got a powerful base w/ nice traction, it will be harder to defend you.
b) If your manipulator breaks or playing defense fits your alliance better, you can play defense.

That was our philosphy for this year. We could put 5-6 tubes in a good match (after we redid the arm, and good matches didn't come often ;) ), but we fould ourselves playing defense much more.

Re: FRIST provided transmissions survey
 

Enhancing on this note:
You don't need a shifting transmission to play defense. Simply getting in between an opponent and their target is enough to keep that opponent from scoring.

Also, a good clip on the corner can knock an opponent off target for a little bit.

A lot of the time, I see wheels spinning against the carpet, meaning teams have too much torque and not enough traction. So, that extra torque from low gear isn't being put to any use. I'd say it's best to be quick and use momentum to knock opponents around. I'm not saying that ramming is the best way, even bumping starting from a couple feet away is adequate.

Re: FIRST provided transmissions survey
 

I love the first transmissions because they never break, have good power and speed, and gives team that build there own a chance to build something better then what the mass amount of teams use. The last thing i want to see is a round of 6 robots not moving because they can't build a gearbox. No one wants to win a game because of a broken robot. Not even in the finals

Edit i showed this post to a teammate that reminded me that we should go back to the old trans this years banebot tran was not up to the task like years prior

Re: FIRST provided transmissions survey
 

You need to match your transmission to your strategy. Whether you use a multi-speed transmission or a single speed KOP transmission, you need to know the strengths and weaknesses of your choices and match that up against your needs for your strategy.

Many people here are against the Banebots transmissions because of the carrier plate and carrier pin issues. Fact is (like any transmission you use) you need to understand the forces being put on to the transmissions.

Last year, with 4 Banebots 56mm gearboxes, 16:1 modification, 4WD, 1.2 CoF 7-1/2" pneumatic tires, we were able to successfully defend the rack against even the most potent scorers.

We didn't go with the AM Single speed (only ones in our price range) because we couldn't get the 16:1 ratio we wanted and the motors would have stalled before the tires broke free. With the banebot 16:1s we only broke free at stall torque.

As I said, match your parts to your strategy (or your strategy to your available parts).

Re: FIRST provided transmissions survey
 

The first Transmission does not need to be the most powerful or the fastest. Its does need to be Indestructible.

Re: FIRST provided transmissions survey
 

Agreed. The FIRST transmission should be a workhorse because it'll be the one chosen when a team cannot design their own. It must be able to take a beating.

It does not need to be the fastest or the most efficient or the most powerful, it just needs to be reliable. My hope is that FIRST and Banebots learn from this past years experiances and make that transmission more robust. I believe that last years transmissions were good, but FIRST teams tend to push things beyond their tolerances ... probably because we have been spoiled by having large safety margins on the mechanical parts supplied in the KOP and therefore didn't look at the material strength.

Re: FRIST provided transmissions survey
 

Prove it. 330 has been known to go over opponents this year, when said opponent got between them and the rack. They aren't the only team to do this, either. Last year, that strategy only worked on a low-mounted shooter. 2005 is that last year that that really worked. (OK, some teams it does work against. But those tend to be a minority.)

The corner clip works much better, but is still risky if there are multiple targets and doesn't work nearly as well if a turret is involved.

Single-speed defense, played well, can be a real pain. Played poorly, it's a minor annoyance. (These are from the team being defended's perspective.)

Re: FIRST provided transmissions survey
 

It's kind of absurd to rank the two on reduction.... The additional reduction needed could most likely have been done in sprockets (Or did you direct drive the wheels?)

Re: FIRST provided transmissions survey
 

We used direct drive on all 4 wheels and while we could have reduced the AMs further, that would have had to have been a secondary operation (and another thing that could break).

Re: FIRST provided transmissions survey
 

Teams with non-mech. experts can put together some parts in CAD to get the basic concepts down. Unfortunately the base unmodified parts also usually make your transmission heavier than the stock KOP transmission. So it's really it becomes a time trade off for me personally, since right now I lack the knowledge (and time to learn) making custom/fancy parts in CAD for a CNC. For this year I'm simply trying to figure gearing arrangements for a simple shifting transmission. I doubt we'll have a use for it in the build season since not only is it heavier than we typically desire, we can also modify the strategy during the game to make up for lack of speed (most of the mentors here seem to be better tacticians than builders, myself included).

On another note, it's a bummer to have unit-vector based algorithms for a driver-centric holonomic drive figured out (and a possible student who's interested in learning them) only to (currently) lack the necessary mechanical expertise to make it a reality -- that's why unless things change I am still comfortable sticking with inexpensive, reliable stock transmissions -- the modified banebots did very well for us this year. Plus it allows for more time on the other important parts of the robot if we decide to do an omni drive.

Eventually, if they stick with FIRST long enough, mentors learn enough about every part of the robot that it becomes easier and easier to bring students up to speed each year, thereby advancing the complexity/reliability of everything. So in essence, it really boils down to the people you have that make up your team as to whether you should put the time into a custom transmission.

Re: FIRST provided transmissions survey
 

I have two suggestions here;

for the shifter you're talking about, try to make a 2-speed derivation of team 33's. they made it comlpetely on a lathe and a drill press with an x-y. There isn't that much lathework, so I'm sure you could ask around to get it done if you don't have a lathe.

"lack the necessary mechanical expertise to make it a reality"
And for this one... that's where off the shelf can be a life saver! AndyMark.biz, ifirobotics.com (heck, even robotmarketplace), etc... all have mechanical products that can be very useful.

Re: FIRST provided transmissions survey
 

FIRST should try to continue to provide kit transmissions, trannies are expensive, time consuming and maufacturing intensive. Not all teams have the ablity to make one I think it is a great idea to provide a KOP transmission and it should be continued. Honestly with the way Andymark is going no one is going to have to make there own custom transmissions for the price, reliablity and features you can't beat them. Teams that want to make there own custom transmissions are going to make them. FIRST is always trying to improve the overall excitement and competitiveness of the events, therefore it is a good idea to provide transmissions for rookie and inexperienced teams.