Quote:
Originally Posted by Ether
Yup.
Although the bigger question here is, do they really need a filter at all? If they're reading the encoder delta counts every execution cycle and dividing by the cycle period, there's already a whole lotta averagin' goin' on (except at very low speeds).
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Yup
For our team, we plan to bypass getRate() and derive encoder rate by (encoder – encoder_last)/T where T is the loop update time. Our typical wheel speed is 2000 rpm or 33.3 rps . The encoder has 250cnts per rev so there are about 8333 cnts/sec. With a 20 ms loop, there are 167 cnts per cycle. If 1 pulse is missed, it is less than .6% error. The code wheel slit phase errors are being averaged over half of the wheel so much of the high frequency phase variations that would affect getRate() are averaged out.