Thanks for the answers guy's.
to get into more details (I am only starting so I do not have a lot of experience), we were talking about "big" servo motors. I have never seen a servo motor in my life (that I knew it is a servo motor), but we were talking about "big" motors, big like - lot of torque and high speed (10Kg to 100Kg motors, 10-20Nm). Note that this was theoretical debate, I do not need this kind of power and if I do I would probably know much more then a noob. I was thinking about stepper motor, as I have experience with stepper motors (actually seen them, controlled them using 16F84), small ones, but the principle is the same, then the other party in the talk mentioned servo's. As far as I read on the net, servo is limited movement (90-270 degrees) feedback controlled motor (with potentiomenter or some other positioning encoder) that can have different torque, speed, accuracy, but it does not spin continuously.
Thing is, I defined the project with
- stepper or dc motor
- encoder (mechanical) that will get feedback on "position" or "movement increment"
- controller driving motor (stepper or dc) using the input from external source (for control) and encoder (to achieve precision)
and the answer I got is "you can find servo to do that for you"
That is why I posted the question.
In real life, I know how to drive DC and stepper. (not too good as I still need lot of practice, still have not figured out the difference between brushless dc, this dc, that dc, 2pole bi polar, 4pole unipolar, 4pole bipolar ... I know the theory, at least some of it, but still need to test all that in real life)