andypugh wrote:jmelson wrote:
No, without commutation info, BLDC would have no idea what poles to activate.
So, I don't think that will work.
It's not a great or preferred solution, but there is an alignment routine built in to bldc which blindly energises the poles in a particular pattern and takes note of the resulting encoder counts.
OK, that sounds quite interesting. You'd have to move the motor up to one
full turn to reach the index position, then the encoder count would jump by how
far you'd moved it when the encoder sees the index position.
It might be simpler to swap (or add) an encoder with a more conventional output. Some exist which also output conventional Hall signals too. (programable for pole count) which largely solves the commutation problem.
Yes, you could put on a Renco or Avago 6-channel encoder, although it would take a bit of hacking.
The Fanuc motors have a proprietary Oldham-like coupling between motor and encoder.
You might be able to adapt a kit encoder to the shaft after removing the coupling part.
Then, you'd have to phase the encoder to the motor poles. The advantage of the Fanuc
encoders is they are VERY high resolution, 32K, 64K, 128K and 1024K counts/rev!
And, the only way to do that is to send a pseudo-absolute position value when requested,
the quadrature rates would become insane.
Jon
