Method for inspecting normality of a spindle of a machine tool

A method for inspecting normality of a spindle of a machine tool, the method to be implemented by a computer device, the machine tool including the spindle and a vibration sensor to sense vibration of the spindle, said method comprising steps of:

• A) receiving a vibration signal generated by the vibration sensor that senses vibration of the spindle during an operation period in which the spindle is in operation, the vibration signal including a plurality of vibration magnitude values that respectively correspond to multiple time points in the operation period;
• B) performing spectral analysis on the vibration signal to obtain a plurality of frequency-domain eigenvalues;
• C) performing time domain analysis on the vibration signal to obtain a plurality of time-domain eigenvalues;
• D) performing principal components analysis on the frequency-domain eigenvalues and the time-domain eigenvalues to obtain a plurality of analysis data pieces that respectively correspond to multiple principal components obtained from the principal components analysis, each of the analysis data pieces including a plurality of analysis eigenvalues;
• E) for each of the analysis data pieces, building a Gaussian model based on the analysis eigenvalues of the analysis data piece;
• F) building a Gaussian mixture model based on the Gaussian models built respectively for the analysis data pieces;
• G) acquiring a difference between the Gaussian mixture model and a predetermined reference model;
• and
• H) generating an inspection result that indicates whether the machine tool operates normally based on the difference and a predetermined threshold.