The Detection of Resonance Frequency in Motion Control Systems

Because of the flexibility of mechanical linkages and high control gains, mechanical resonance may occur, causing torsional vibrations between the motor and load in servo control systems. These vibrations generate velocity and positioning errors for the control system and may damage the system components. This study presents a resonance frequency tracking scheme for servo control systems. The scheme uses velocity error and bandpass filters to track resonance frequencies. After detection, a notch filter in series to the current command is enabled to suppress the vibration. This scheme can be employed during the initial setup and for online resonance frequency tracking. In addition, the proposed scheme can be used to identify all vibrational frequencies in systems with multiple resonant frequencies.