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Originally Posted by Alan Anderson
I'm confused. I'm getting the impression you don't understand how quadrature encoding works, but I can't believe that's the case
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Sorry for the confusion...Its funny, I know we have the exact same picture in mind, but choose to describe it so differently. So I will break the limit cycle in interest of your sanity and perhaps any readers and not try to re clarify.
Quote:
Kevin Watson implemented two different schemes for reading quadrature encoders, based on the different features of hardware interrupts on the PIC input pins. I used a routine that would count up and down as the phase A signal changed state; the other could be fooled into continually incrementing or continually decrementing at the noisy edge. It was indeed used for closed loop control, with two encoders being read to determine robot heading based on the difference in their values. (A third encoder provided odometer information. It was read by the simpler routine because it did not suffer from noisy rotational motion.)
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Did your decoder also use B phase to halt the continuous counting similar to Kevin? If so wouldn't it have incorporated a type of hysteresis?
Probably at that time you did not have a need for special rate processing of your decoded heading unless heading rate was involved in your loop...right?