Servo Amplifier/Servomotor Compatibility Study

The report presents a study of the stability problem (tendency for unwanted oscillation) of a servo amplifier driving a servomotor. Servo amplifier stability is affected by the servomotor impedance being reflected back into the amplifier internal feedback loop. The servo amplifier/servomotor modeling techniques used for stability evaluation are considered. The study develops techniques for evaluating, testing, and specifying servo amplifier/servomotor combinations with respect to stability. Recommendations are made to modify present specifications to include parameters which will insure stable operation of amplifier/motor combinations. A limited number of commercially available servo amplifiers with standard servomotors are evaluated and results are summarized.