[Yovav]

Hi
I know I am bumping up the thread, and I hope it's all right, I had a few insight about the Q I ask and I finally understood the answers I got, and I didn’t want people to read this thread and might get confused.
For some reason I confused brushless DC with rotary encoders, brushless DC do need encoders for their operation but of course brush DC can also have rotary encoders (I now know I am stating the obvious) .
my system composed of one axis with gear rack and two axis with ball screw, to prevent backlash I intend on using linear encoders for the gear rack axis+ rotary encoder for the axis engine (to compensate for the engine gear and the gear rack), and for the other two axis I will use rotary encoder on the engine + rotary encoder on the ball screw shaft (here I don’t think I need linear encoder since the backlash on the shaft itself is very low, and only need to compensate for the engine gear).
And now I realized I don’t need brushless DC, only brush DC with an amplifier, part of my project is building the control of the machine, so I don’t need a driver just an H-bridge amplifier.
Sorry I didn’t understood your answers earlier, but I guess it's better late than never.
Yovav