Thread: Shifting Gears
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Unread 09-11-2003, 00:50
DanL DanL is offline
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I second the whole bevel-gears thing... we had lots of problems with the gears meshing until we did this.

Another thing I suggest goes to the programmers. When shifting, even our team's better drivers had problems getting the speed right. In the heat of the battle, it's hard NOT to be going in full throttle. As a result, when we were shifting, all of our drivers were putting too much speed in between gears, and the gears were making the clang-clang-clang noise of dhoom from sliding past each other and not meshing. What we did was we used two digital inputs and four limit switches (wired as shown in the 1-min Paint diagram below) to tell us when we were engaged and when we weren't engaged. At any point in time, the High-Gear OR the Low-Gear input must be 1. If both are 0, that means we're not engaged. When we're not engaged, the program limits the speed to something like 1/5th or 1/6th of the maximum speed - slow enough for the gears to finally mesh. This system is nice because its fully automatic - the driver can push as hard as he wants on the joysticks because the robot automatically limits the max speed.

Depending on how easily your system shifts, you might also consider having the program automatically go forward and backwards. We found that if you jiggle between forwards and backwards, it shifts faster. It's something you need to test out on your system and see how it works for you.

Hope all this made sense... it's 1am and I'm falling asleep, so my grammar probably isn't up to par. If you don't understand something, post and I'll get back to you in the morning.
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Dan L
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Software Engineer, Vecna Technologies