Tool wear status recognition based on Mahalanobis distance

To improve the reliability of current signal monitoring tool wear status, a method based on Mahalanobis distance to identify tool wear status is proposed. First, the obtained current signal is analysed in time domain, frequency domain and wavelet domain, and several features that have good correlation with tool wear status are selected to form the feature vector. The feature vector of the current signal in normal tool wear status is taken as the reference vector. Then calculate the Mahalanobis distance value of the feature vectors of the current signal of the tool with moderate wear and severe wear, so that two corresponding thresholds T ₁ and T ₂ can be obtained. The feature vector of an unknown wear status is calculated using the Mahalanobis distance and then compared with the two thresholds obtained previously. When the calculated value is between threshold T ₁ and T ₂ , the tool is judged to be in moderate wear status. When its Mahalanobis distance value is greater than the threshold T ₂ , it is judged that the tool has been seriously worn. Finally, multiple unknown wear status is identified. It is believed that the recognition method based on Mahalanobis distance can accurately determine the tool wear status.