FIRST provided transmissions survey

[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.

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.

[EricH]

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.

[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.

[AdamHeard]

Originally Posted by InfernoX14

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.

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.

[Dan Petrovic]

Originally Posted by AdamHeard

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.

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.

[nuggetsyl]

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

[Daniel_LaFleur]

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).

[nuggetsyl]

Originally Posted by Daniel_LaFleur

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).

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

[Daniel_LaFleur]

Originally Posted by nuggetsyl

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

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.