tmc2240: sin/cos phase offset calibration

[nefelim4ag]

Coils can be unequal due to factory tolerances
This calibration allows us to make the motor symmetric, which will reduce rotor oscillation during rotation

For now, for easier testing.
Happy path looks like so:

G28
TMC_PHASE_OFFSET_CALIBRATE STEPPER=stepper_z
G0 Z105 F600
G0 Z5 F600
G0 Z105 F600
<output stabilizes at some value>
TMC_PHASE_OFFSET_CALIBRATE STEPPER=stepper_z
SAVE_CONFIG

For better results motor should be unloaded, for Z it is movement down.
For me, it stabilizes around:

// Test offset: -11 ~ 82 degree

*I have only one TMC2240, if I remember correctly, on the X motor, it was about the same value

I think it is a good idea to validate the accelerometer output before and after the offset with low accelerations.
To sample the whole speed/rotational range.

Thanks,
-Timofey

---

Testing can be done with:

git fetch origin pull/7183/head
git checkout FETCH_HEAD
sudo systemctl restart klipper

or by a simple copy of tmc2240.py content

[nefelim4ag]

Just for the record, from available testing.
There is some dependency on speed, which is not intuitive to me.
So, the right speed is an open question.

*1RPS
OFFSET_90 does a thing, if calibrated wrong, rotor phases oscillate more:

At some point in calibration, it looks weird. I can't say it is better or worse; it seems smoother, but the amplitude is larger.

[nefelim4ag]

Okay, another data point, I though second time that they sound different, maybe better.
But I'm confused.
It is CoreXY, diagonal moves, on the one hand, I can count full steps and graphs are more smooth, there are less deep in the middle of the step, as in the graphs above.
On the other hand, again, the amplitude looks larger than before.

Stepper X

Stepper Y

[ifreislich]

Just some data. The results seem related to rotation speed.

3.3rps:
z: New offset: -1 ~ 89 degree
z1: New offset: -1 ~ 89 degree

2.4rps:
z: New offset: -9 ~ 84 degree
z1: New offset: -9 ~ 84 degree

2rps:
z: New offset: -2 ~ 89 degree
z1: New offset: -3 ~ 88 degree

1.5rps:
z: New offset: 1 ~ 91 degree
z1: New offset: 1 ~ 91 degree

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