I’ve been looking over a lot of threads, new and old. And I’ve noticed one constant: Complaints about the KOP transmissions. I’m personally of the camp to design my own more complex transmission, but I had a brain fart: If you all dislike the KOP transmission, would any of you be willing to step up and design a gearbox that could be used by all the teams? It would have to be low cost, decently low weight, and durable. I’ll design one just for kicks and giggles, but would any of the myriad of complainers be willing to back their complaints with action?
Frame designed by JVN, transmissions by Paul Copioli.
(Granted, the kit transmissions of that era weren’t the lightest things around–but they held together, and you could take weight out of them.)
No need to design one. Anyone looking to fabricate their own isn’t going to be able to do so for less than $98–AM Single Speed
Darn… Seeing the title of the thread, I was about to reference them…
Seriously now… $98 is a steal for those, it’d be awesome if FIRST put them in the kit (for both teams and for Andy Baker/Mark Koors). My only gripe is that they only facemount (which will probably only mess with new teams… for some reason it feels really wrong to have a complaint about something Andy designed); but that’s nothing compared to the rest.
EDIT: very true Cory (below). A lot of times problems are easier than I imagine.
It wouldn’t be very hard even for a low resource team to get a couple pieces of aluminum angle to fabricate brackets that would allow them to mount through the bottom of the transmission, though.
Talking about transmissions you could buy wasn’t really the point, or I might have titled the thread “Best store-bought alternatives to the KOP transmissions.”
For those of you that care about such things, here are some little known factoids about the KOP transmissions of 2005 - 2006:
-
Designed by Paul Copioli and JVN.
-
Design, prototyping, testing completed by Paul Copioli and Giovanni Copioli (4 years old at the time) was 100% donated time.
-
The gears inside the transmision were manufactured by AndyMark. I think the motor shafts were too.
-
The die cast aluminum housing source was found by AndyMark.
-
The cost of the gearbox without the motors and bearings was around $30. The bearings were donated in 2005 and 2006.
-
The gears were not lightened due to cost, but teams could easily do it themselves.
-
The gearbox was designed for back to back operation. the 2 gearboxes could be stacked to create an arm gearbox capable of a ratio of 163:1. The gearbox was designed to take this load.
Anyway, that’s all I have for now.
The point I (and I believe Cory) was making is that the AM single speed (and the 05-06 KOP trans) is the ideal Kit transmission; It’s easy to work with for rookies, Incredibly durable, rather cheap to produce, and most importantly it’s as simple as possible (We don’t want first to give out shifting transmissions you can just bolt on).
EDIT: Interesting information there Paul. The AM single speed has the exact same gears, right? how hard would it be to do the back to back with two Single speeds?
EDIT2: dtengineering… Team 33 put out an excellent package for their shifter with a complete itemized parts list and a total cost, very useful.
The banebots are semi reliable now… but compare how much torque one of those can take before destroying itself to the AM single/Old KOP… The safety factor in those two make it so you’ll never, ever have to worry about them.
I love the idea for an arm gearbox that could take small/Big CIM, FP and globe…
There are some excellent papers on transmission designs in the White Papers here on CD. Teams have been very generous in sharing their ideas.
Perhaps one of the things that would be most helpful to teams wanting to build a transmission – either based on one of these designs or a new one as proposed – would be a list of components hyperlinked to on-line suppliers. One of the real tricks to building a competitive robot is knowing what parts are available, how much they cost, what their strengths and weaknesses are and where to get them from.
That said, there is still room for innovation and collaboration. An arm transmission integrated with a sensor and PID feedback loop to hold position would be helpful to many teams, I think.
As for the Banebots trannies, yes, there was a lot of concern about them before they received the carrier plate upgrades. Since then they have been at least as reliable as any other transmission. They are ideally suited for direct drive applications, which allows teams to do away with heavy and unreliable drive chains, and are very well designed for adding a very functionional optical encoder for speed and distance measurements.
Jason
P.S. Of course just because there is are existing solutions to a problem does not mean there aren’t better ones.
Who’s this “we”? 
Surely there must be someone who would like to see the FRC KoP include shifting transmissions you can just bolt on.
hmm… I guess the we is me, assuming others agree. But those would probably cost FIRST a good amount of money, and not all teams would use them (Which wouldn’t be as big a deal with a cheaper, single speed). Either that, or they are cheap and not very durable/reliable.
Also, with the AM shifters, any team that wants a bolt on trans can have it. Or, with a little more work, the dewalts can do that as well (Those are clamp on… but close enough).
Right… but why would you spend your time to design/fabricate something when you could purchase a equal/superior offering that costs significantly less than it would take for you to make the same thing, if you price out materials, machine, and design time.
This is particularly true since the KOP transmissions are primarily used by teams who a) don’t have the resources to make their own custom drive system, or b) use it because they want something that will run in a day or two out of the box.
In both instances, a custom designed transmission that the plans are available is not desirable. Team A cannot make one, because they do not have the resources to do so. Team B will not make one, because it will divert their efforts from their subsystems.
In either case, my answer remains the same. For a single speed kitbot drive, I highly, highly doubt you could possibly find a more economical solution than the AM single speed. Consider that in the Bay Area, a machine shop will charge you between $100-120 an hour to make parts for you. It would take at least 10-15 hours to machine two transmissions. Possibly more. That’s $1500. Materials are probably another $100 or so. The kicker is that if you for some reason did want to make one yourself, just download the CAD files from Andymark and machine the parts yourself.
The 05-06 KOP transmission was amazing, by FAR the best KOP transmission, and, IMO, better than the AM single speed (due to the arm configuration and longer output shaft). The only thing I can think of that would be a nice addition is adapter plates so you do not have to modify the transmission to use other motors with it.
The 05-06 season was my first year and I didnt work on mechanical but we never had any issues with them and they worked great. If they still sold them I would definitely pick a few.
Or how about c) decide that the KOP tranny is the best one for their application? At least one of the 2005 champions decided that the kit trannies would provide what they wanted (strong, cheap, good gear ratio, easy maintenance) and went for it. Then in 2007, they decided to use an AndyMark 2-speed for the same reason–they knew it would provide what they wanted.
Thanks, Paul, for this clarity. I’ll tweak it a bit:
For the 2005 KOP transmissions, AndyMark provided the aluminum faceplate and 3 of the gears. We did not provide the shafts, but we did give a bit of advice on the shaft design. Mark found the casting supplier, as it was a supplier of product castings to Delphi.
Thanks to Paul, IFI and FIRST for this great opportunity that was a large factor in helping our company become sucessful during our first year in 2005.
This is a great discussion. Thanks for starting this thread, Craig.
Andy B.
I can vouch for the AM kitbot gearboxes being rock solid. In our tetra bot, we had two FP motors -> two AM planetaries (2005) which fed a single AM kitbot gearbox. This gearbox then fed another AM gearbox… and it held together great for the season… and for tons of demo’s we’ve done with it 2005 and since… still going strong!
Also, for a robotics education club I run at a private high school locally, I use the modern AndyMark single speed transmissions… they’re rock solid, tough, and EXCELLENT for teaching mechanical advantage (simple and easy to understand for just-starting-out engineers). Not to mention, the pair of robots we have that use these AM transmissions run off road (dusty environment) doing autonomous navigation, no problems at all.
I remember andy was caught off guard when he saw this order come from 1024… wondered why we would be using singe speed gearboxes when we used two speeds the previous year… yeah i can see how that could be confusing.
They’re a great product at the right price for educators and all wanting a nice, reliable, inexpensive reduction. Thanks Andy!
-q
I kinda like the old wibbly-wobbly drill motors and gearboxes, where you needed a wing and a prayer to put it together and keep it together. It took a bit of understanding as well as a bit of art to make it all work.
We talk about how it is extra work for a rookie team to mount the single speed AM Gearbox at its base. I remember our rookie year trying to figure out which is easier to mount, the plastic handle of the drill motor or the FP plastic transmission. My, my, how times have changed.
My boss once told me “There is all ways a better solution; Good engineers just know when to stop”.