基于S变换的热连轧机耦合振动特征提取
Coupling Vibration Feature Extraction of Hot Continuous Rolling Mill Based on Adaptive Frequency Domain Filtering and S Transform

提出一种基于短时傅里叶变换的自适应频域滤波方法，将噪声信号与振动特征成功地分离。根据短时傅里叶变换和功率法设定的阀值，自动捕捉了振动信号在不同时间段的优势频率。对振动信号、压下液压缸压力信号和伺服阀给定信号做短时傅里叶变换后，热连轧机振动被诊断为液机耦合振动。利用离散小波变换和S变换相结合的方法对轧机振动信号进行分析，确定轧机起振的时间为液压压下系统的投入时间，证明了热连轧机存在液机耦合振动现象。
Rolling mill vibration signals that are time-varying and random are often affected by noise interference, so that frequency domain analysis cannot identify and extract fault features. The adaptive frequency domain filtering method has been proposed to successfully separate noise signals and vibration characteristics based on short-time Fourier transform (STFT). First, according to STFT and a threshold set by the power method, the dominant frequencies of vibration signals in different time periods are automatically captured. After the vibration signal, hydraulic cylinder pressure signal, and servo valve reference signal have been captured by STFT, the hot continuous rolling mill is diagnosed with mechanical-hydraulic coupling vibration. With the combination method of discrete wavelet transform and S transform, the rolling mill vibration signal is analyzed, which determines that the rolling mill vibration start-up time is the investment time of the hydraulic pressure system, thus proving the existence of mechanical-hydraulic coupling vibration.