Vibration analysis using wavelet transform and fuzzy logic for shaft misalignment

• Main Authors: Amit Umbrajkaar, Arunagiri Krishnamoorthy
• Format: Article
• Language: English
• Published: JVE International 2018-12-01
• Series: Journal of Vibroengineering
• Subjects: discrete wavelet transforms (DWT); misalignment; overall vibration level (OVL); fuzzy inference system (FIS); and degree of misalignment (DoM)
• Online Access: https://www.jvejournals.com/article/19611

In most of rotating kind of machinery, misalignment is commonly observed defect. Though machines are installed to zero-zero aligned condition in initial stage, in due course of run time operation misalignment get introduced due thermal distortion, asymmetry of forces exerted and inadequate assembly of parts. This paper presents a method of misalignment prediction from output vibration signal which is based on combined DWT (Discrete Wavelet Transform) and Fuzzy Logic approach. DWT helps in multilevel decomposition of vibration signal to understand where and at what instant misalignment occurs. This involves selection of mother wavelet. The FIS (Fuzzy Inference System) is combined with DWT to predict degree of misalignment present. An inclusion of FIS has improved prediction accuracy of Degree of Misalignment (DoM) which has claimed error less than one percent (1 %).