Milling chatter monitoring method based on variational mode decomposition and tracking threshold

The invention discloses a milling chatter on-line monitoring method based on variational mode decomposition and a tracking threshold. The milling chatter on-line monitoring method comprises the flow processing of three parts, in a first part, three-way vibration acceleration signal samples in a stable milling state and a chatter state are collected, extractable feature samples are obtained, and frequency band power are extracted as features; in a second part, NC codes in a machining process are obtained, segmentation processing is performed in combination with a process route, feeding time of each segment is calculated, benchmarking of a machining segment and a threshold model is completed, and a tracking threshold model is obtained; and in a third part, the model is synchronized with the machining process through servo communication, signals are collected on line, characteristic values are calculated in real time, and the characteristic values are input into the model for comparison. Compared with the prior