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Unread 10-01-2005, 19:33
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Re: Slickest drive transmission yet...

I'll repeat my question from the other thread here since I haven't seen the software paper yet. Now that the season has kicked-off, I expect the last thing on your mind is documenting last year's work.

Jim, could you answer some general questions about how your software works?
1. Is shifting based on RPM alone? What other factors are used to determine when to shift? Current? Voltage? The commanded PWM value? To put it another way, are the shift points fixed, or are they different when you are accelerating at 50% throttle?

2. I assume there is some kind of hysteresis. Is it a simple pair of shift-up/shift-down values? Or do you add something like a "dwell time"?

3. Do the left and right transmissions shift at the same time? I'd imagine that keeping both sides in the same gear would make it easier to match speeds and keep the 'bot going in a straight line.

Of course I don't expect you to give away all your secrets, Gracious Professionalism or no. But some general guidance about the operation of the shifting software would be helpful.

Once again, great job 33! It's a sweet design.