Position accuracy

Hi wall0069

the encoder precision has not direct result in the system precision. It just tell back the position of the wheel to the ESC so it could work accordingly. The stupidiest version of a polyphase motor (a BLDC is a kind of) is as a stepper (only one phase is powered and moves the wheel into a specific position). For LRK BLDCs the internal magnetic gear comes into play (reducing the angle per cycle). So every different motor (pole : coil ratio) is different.

If you want a high precision position use microstepper instead.

Cheers

Sam

Hi Wall0069

that has nothing to do if you use FOC or BC, as the poles generally want to allign itself to the opposite (N-S + S-N). Depending if your BLDC motor is designed as a "usual" LRK principle or "normal" polyphasic motor the rotation (and so the physical degrees per electrical turn (=3*120°)) varies per motor and could be calculated if you knew the inner pole count (depending if LRK or normal) to the outer pole number. The VESC is using the "eRPM" term as electrical turn.

If you look up LRK motor you can find this for example:

https://www.aerodesign.de/peter/2001/LRK350/Paper_from%20_Wroclaw.html

which explains in detail how it works and how the turn per eRPM can be calculated. A third of the electric turn (=120°) is the minimum angle your motor can do. Thanks to the momentum of the motor a smaller degree could be arranged as the weight restricts the change per "push". But that is not the thought of an ESC, but of a stepper:

https://en.wikipedia.org/wiki/Stepper_motor

to reach high precision angles.

Cheers

Sam