A Transient Performance Evaluation Method for Turret Systems Based on Motor Current Signal Analysis

The turret system is one of the key subsystems of CNC machine tools, and its transient performance has a direct impact on the machining accuracy and reliability. As a typical electromechanical coupling system, there is inevitably some inherent relationship between the transient performance of the turret system and the amplitude change of the control motor's current signal. Therefore, a transient performance evaluation method based on motor current signal analysis (MCSA) is proposed in this paper. The variational mode decomposition (VMD) and Hilbert transform amplitude demodulation (HTAD) methods are utilized to obtain the multi-scale modes of the measured current signal and extract the instantaneous amplitude (IA) of each mode, respectively, which contributes to enhancing some weak components closely related to transient performance. Time-domain statistical indicators and entropy indicators are calculated to measure the probability distribution and complexity of the IA of each mode, which visualizes the inherent relationship between the modes and transient performance. The results indicate that by setting reasonable thresholds for the statistical indicators of the IA of the feature modes, it is possible to correctly evaluate and effectively distinguish whether the transient performance of turret systems is good or poor.