Resonant load control methods for industrial servo drives

High-performance servo drives are often limited by mechanical load resonance. In this paper, seven methods of resonant-load control are compared for their ability to improve performance in the presence of a low-frequency (100 Hz) lightly damped resonance. The seven methods are: notch filter, bi-quad filter, rigid body observers, low-pass filter, observer filtering, active resonance damping and center-of-mass control. Several of the methods are based on filtering the command signal; the remaining methods are based on signals acquired from an observer. Development of these methods is presented; each method is applied to a physical system and evaluated for effects on command response and dynamic stiffness.