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Re: Diffrent Transmission Advantages
Our first year, team 2158 used Banebots. A while ago, I asked Richard, our mentor, how they worked, and he said, "Oh, they're great! The seize up and everything!" These were the old Banebots. Last year, we used their transmissions on all of the non-drive motors, and there were no problems except for the one that had a case we lathed that got some metal shavings left in it. It was soon fixed and worked fine.
For the drive train last year, we used 4-motor 6-wheel drive with 4 DeWalt transmissions. All I have to say is that if you have 6 regular members on your robotics team, don't use DeWalts. They were an unnecessary pain and easily took up 2 or 3 days of build time. We had to keep the drive train very low to the ground because of the 13' forklift we built on top of it, so all of the motors were squashed down onto a support bar with the transmissions screwed to the P-channel frame and hose clamped down for alignment. We have never gotten into 3rd gear. We refer to it as neutral. We originally settled on a shifting platform so we would have precision for lining up to the balls and high speed for doing laps, but it turned out we could line up plenty precisely in high gear, and we never used low gear. This year, that should be even less of a concern due to the increased linearity in response of the Jaguars over the Victors. Currently, we're having a big problem with the drive current, as we can drain a battery from just driving around for about 4 minutes, but the problem is impossible to diagnose because of the complication in mechanical parts. We know we had some magic wires (based on the magic of electrons flowing through dielectrics), but the transmissions are masking everything else.
That being said, I'd say for beginning teams, AndyMark is the simplest, most rugged design, with Banebots slightly behind them. The Banebots 12:1 single motor gearbox is the same weight as the AndyMark Toughbox, but more expensive. The Toughbox is also easily configurable for different gear ratios, whereas you need to buy a different Banebots transmission or remove one of the stages and cut the case down to get a different ratio. One thing I will give Banebots is the physical size of their gearboxes is smaller than the AM ones. Even pit against the new GEM500 (about the same size, no weight data), the Banebots wins out as the cheaper and easier to mount (the GEM is completely round with no mount plates other than the front and back), and there is no match in size for the dual-motor Banebots.
So overall, if you're a more or less new team without many resources, stick with the kit transmission. If you have a few more resources and you need shifting cheaply, use DeWalt with caution and care. And if you have enough resources, I encourage the use of custom transmissions, as they will give you everything that your team specifically needs. Our team toyed around with the idea of building an IVT or at least a CVT of some sort, but I sincerely doubt that will happen looking at our resources and funds. I'll probably peg for the Toughboxes this year, looking at all of our drive train trouble from this year and all of the possible culprits we have yet to narrow down. One thing I will say as a general rule, is one output sprocket is better than two, that's just twice the number of misaligned teeth you'll probably have in your drive train.
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