Detection of resonance frequency in motion control systems

Due to the elastic nature of mechanical linkages and high control gains mechanical resonance may occur and cause torsional vibrations between motor and load in servo control systems. These vibrations introduce velocity and positioning errors to the control system and may be harmful to the system components. In this paper, a resonance frequency tracking scheme for servo control systems is presented. The scheme uses velocity error and band pass filters to track resonance frequencies. After the detection a notch filter cascaded to the torque command can be set to suppress the vibration. This scheme can be used in the initial setup and on-line resonance frequency tracking. Also, it can be used to identify all the vibrational frequencies in the systems with multiple resonant frequencies.