Expected noise in vel_estimate reading?

1

Can anyone tell me what amount of noise you’d expect to see when plotting vel_estimate, when the motor itself is completely motionless?
EDIT: and with what encoder, encoder mode you’re using, obviously.

2

Really depends. With the AMT102s from the shop, 0 noise. With a magnetic SPI encoder… it can vary and it depends on encoder.config.bandwidth, but maybe +/- 0.1 turns/sec?

3

Thanks for your response. I was seeing +/-0.3 when bandwidth=1000, it came down to +/-0.01 when bandwidth=100.

Is there any downside to having bandwidth as low as possible? I see that pos_estimate takes a while to converge at really, really low bandwidths (bandwidth=1) but I can’t tell from the liveplotter at what point this becomes negligible (from the perspective of controller performance).

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4

It creates an error between the actual angle and the sensed angle. This can cause issues with the motor control, but it’s going to be totally application dependent.

5

Okay, I will experiment. Thanks for the info.

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