Recently I have been spending a lot of time on getting FOC running and currently I have both sensored (with pulse encoder) and sensorless FOC working. My code is inspired by this code:
https://github.com/madcowswe/Servo/blob/master/FPGA/software/ServoDrive/Servo.c
and the sensorless observer is the one described in this paper:
http://cas.ensmp.fr/~praly/Telechargement/Journaux/2010-IEEE_TPEL-Lee-Hong-Nam-Ortega-Praly-Astolfi.pdf
Oskar who wrote the Servo.c file helped me with getting started. Here is one of his videos:
https://www.youtube.com/watch?v=7gK_3eZ16RI
I will upload something to youtube soon as well.
I will try to push the first implementation to github today if everything goes well. For now there is no auto detection of motor parameters, so that has to be done manually, something like this:
http://cache.freescale.com/files/microcontrollers/doc/app_note/AN4680.pdf?pspll=1
I would measure the resistance in a different way though. I would run a certain current in the motor from the power supply and measure the voltage drop across one phase and divide that by the current, then divide that by two as described.
Regarding hw 4.10: I haven't tested it myself, but it is awesome that chaka has tested it already and has it working. I have done the FOC testing with v4.8 and the current offset seems to be less of an issue when using space vector modulation. I think FOC will work fine with 4.7 as well and 4.10 should be even better.
Can i use two esc on the same motor?
You can not connect them in parallel since there is PWM output and synchronizing it will be almost impossible. If they aren't in sync they ESCs will blow up for sure. What you can do, if the motor has many pole pairs, is to take the motor apart and connect different groups of pole pairs individually to different ESCs. There are even some motors available that have six wires that go to different groups of pole pairs.