Hello.
I already had a problem of this kind, then I found electric angles for a separate side of rotation. Now I’ve changed the motor, the encoder. But the problem still remained. With the help of turning equipment, a landing for the magnet was made, I installed it with a deviation of 0.02 mm. The encoder passport says that this deviation can reach 0.3 mm.
In an open cycle, the motor rotates smoothly.
Encoder mt6701
Thanks.
I did a little experiment. I rotated the motor rotor in an open cycle with a step of 0.5 radians. The encoder readings do not coincide with the movements of the rotor. Because of this, there is no smooth rotation in a closed cycle. I noticed that the more poles the motor has, the more accurately the encoder should be installed. For example, a stepper motor with its 50 poles is blocked in a closed cycle at once.
angle_openloop ==============Encoder
0.5 ========================0.55
1 =========================1.03
1.5========================1.47
2=========================1.92
2.5========================2.43
3=========================2.98
3.5========================3.53
4 =========================4.04
4.5========================4.49
5========================= 4.93
5.5========================5.43
6========================= 5.96
6.28=======================6.28
Reading the Datasheet for the MT6701, there is nothing in there about calibration. I know this doesn’t help you much in your current predicament, but look at the MT6835 Datasheet, where it explains the calibration procedure. As I understand it, we have to spin the stepper in open loop for a certain time, while calibration is being performed by the IC.