I work for an aerospace company designing satellites that employ robotics to service other satellites.
We are interested in utilizing back EMF measurement in the stepper motors of our robotic mechanisms to provide sensor-less diagnostic information. I found useful information in STM Application Note #3327, L9942 back EMF stall detection algorithm.
Question: We would like to estimate the SNR of the back EMF generated (signal) to the driving voltage (noise) for our selected motor to determine if it's feasible to use back EMF for state detection; we're assuming anything > 10% is good to move forward (test in lab). Could this be done by taking ratio of the magnitude of back EMF from the above equation to the voltage drop across a motor phase (product of the nominal current through the phase and the phase resistance)?
