Abstract:
The monitoring of health and the technologies that are related to it are an exciting area
of research. The paper proposes a mechanical manufacturing vibration monitoring system
that is based on Hilbert-Huang transformation (HHT) feature extraction to monitor the
running state of the spindle of a mechanical numerical control (NC) machine tool of an
electrocardiogram (ECG) machine. Real-time monitoring of the time–frequency characteristic
quantity of the spindle vibration signal for ECG signals has been made possible
due to the online empirical mode decomposition (EMD) method, which is used to obtain
the time–frequency characteristic quantity of the spindle vibration signal based on HHT.
The experiment shows that the frequency doubling characteristic components in the time–
frequency distribution are obvious in the time interval without copper rod contact, but they
disappear in the time interval during which copper rods are in contact (0.3 1.1 s, 3 4s in the
figure). It has been demonstrated that the system is capable of not only accurately monitoring
the characteristic quantity in the frequency domain of the vibration signal produced
by the NC machine tool spindle, but also of successfully implementing the monitoring of
the time–frequency characteristic quantity in real time.
