Feature extraction from the engine measurement signal of mass characteristic based on wavelet analysis

It was observed that the measurement signals contained some undesired parts in engine mass characteristic measurement test by single pendulum method, which brought some difficulties for extracting parameters of engine mass characteristic. The useable signals were separated from the undesired signals through the wavelet multi-resolution-analysis. Some parameters of the engine system such as the natural frequencies, logarithmic decrement, and the damping ratio were obtained using the useable signals. The impact of the damping on the natural frequencies of the system was also studied. The sources of the undesired signals and the defective workmanship were found by the features analysis of the undesired signals. Results show that the wavelet analysis is a useful tool with practical meanings that may be used to extract the structural dynamic parameters, improve the measurement accuracy and locate the damage in the engine system.