Spectrum construction for non stationary vibration: Application to a moving flexible robot

• Published in: MATEC web of conferences Vol. 20; p. 1004
• Main Authors: Vu, Viet-Hung, Thomas, Marc, Liu, Zhaoheng, Hazel, Bruce
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Les Ulis EDP Sciences 2015
• Subjects: Amplification; Autoregressive models; Computation; Construction methods; Regression analysis; Vibration measurement
• ISSN: 2261-236X; 2274-7214; 2261-236X
• DOI: 10.1051/matecconf/20152001004

This paper presents a method for constructing spectrum in non-stationary vibration using time series vector autoregressive model. A modal classification criterion and a modal amplification factor are introduced based on the eigen-decomposition of the block data matrix. The classical spectrum computation can be therefore modified to amplify only the physical modes and lighten the computation induced modes. In combination with a sliding window technique, it is shown that the method provides a clear, lightweight spectral representation of non stationary vibration. Application on the vibration signals measured from a moving flexible robot along a given trajectory shows the effectiveness and applicability of the method. The technique is integrated in the online modal surveillance software call STAR (Short Time AutoRegressive).