Pedestal looseness extent recognition method for rotating machinery based on vibration sensitive time-frequency feature and manifold learning

Abstract

To realize automation and high accuracy of pedestal looseness extent recognition for rotating machinery, a novel pedestal looseness extent recognition method for rotating machinery based on vibration sensitive time-frequency feature and manifold learning dimension reduction is proposed. Firstly, the pedestal looseness extent of rotating machinery is characterized by vibration signal of rotating machinery and its spectrum, then the time-frequency features are extracted from vibration signal to construct the origin looseness extent feature set. Secondly, the algorithm of looseness sensitivity index is designed to filter out the non-sensitive feature and poor sensitivity feature from the origin looseness extent feature set, avoiding the interference of non-sensitive and poor sensitivity feature. The sensitive features are selected to construct the looseness extent sensitive feature set, which has stronger characterization capabilities than the origin looseness extent feature set. Moreover, an effective manifold learning method called linear local tangent space alignment (LLTSA) is introduced to compress the looseness extent sensitive feature set into the low-dimensional looseness extent sensitive feature set. Finally, the low-dimensional looseness extent sensitive feature set is inputted into weight K nearest neighbor classifier (WKNNC) to recognize the different pedestal looseness extents of rotating machinery, the WKNNC's recognition accuracy is more stable compared with that of a k nearest neighbor classification (KNNC). At the same time, the pedestal looseness extent recognition of rotating machinery is realized. The feasibility and validity of the present method are verified by successful pedestal looseness extent recognition application in a rotating machinery.

Coupling dynamics of pedestal looseness and impact-rub for rotor system with nonlinear support

“…Zhang et al 6 applied the generalized Polynomial Chaos Expansion (gPCE) to gain the nonlinear random responses of the impact-rub rotor system by the probabilistic models. Chen et al 7 proposed a new recognition method of the pedestal looseness degree of the rotating machinery. In view of pedestal looseness fault often occur in the engineering, Ma et al 8 constructed a Finite Element (FE) model with the looseness fault and investigated the dynamic characteristics of one-support looseness and two-support looseness.…”