The invention discloses a gear box composite fault diagnosis method based on reverse editing. The method comprises the steps of: performing initial phase identification, editing, inversion and vectorsuperposition on an original vibration signal according to energy differences of a gear fault signal, a bearing fault signal and noise and conjugate symmetry of Fourier transform, so that effective noise reduction of the signal and division of different energy components in the signal are achieved; applying an amplitude level decomposition method based on the maximum between-cluster variance to automatically decompose energy difference features in the signal to achieve effective separation of composite faults; and performing Hilbert envelope demodulation analysis on the separated fault signalsagain, and finally achieving fault feature extraction and diagnosis. Through simulation analysis of the composite fault signal, effectiveness of the method is verified. Experimental data analysis results also show that the method can effectively separate and diagnose the bearing and gear composite fault in the gear box.

Gear box composite fault diagnosis method based on reverse editing

The invention discloses a character string fuzzy matching and querying method based on an editing distance. The method comprises the following steps: sequentially dividing the query strings accordingto the lengths of the character strings in the paragraphs so as to obtain a query string substring set; when the character strings in the paragraphs are matched with the character strings in the querystring, adding the length of the character string into the matching degree of the original character string of the index corresponding to the character string, adding the character string into a result set when the matching degree of the character string is greater than a preset upper bound value and no repeated element exists in the position list, otherwise, verifying the editing distance of thecharacter string; When the matching degree of the character string is smaller than a preset lower bound value, directly filtering the character string; When the matching degree of the character string is between the preset lower bound value and the preset upper bound value, editing distance verification is carried out on the character string, the difference that paragraphs of different lengths donot affect the matching result can be reflected through the method, and meanwhile the number of editing distance verification operations is small.

Yu Shiwen

Papers

A character string fuzzy matching and query method based on an editing distance