Velocity Guided Chirplet Transform: Utilizing Rotation Speed Information in Time–Frequency Analysis

Time-frequency analysis (TFA) methods are significant in vibration signal analysis and fault diagnosis of mechanical equipment. However, large-scale mechanical equipment such as aerospace engine works under fast-varying rotation speed, leading to blurred time-frequency representation (TFR) from vibration signals for health monitoring. Meanwhile, it should be noticed that with the development of measuring techniques, the difficulty in acquiring rotation speed signals is decreasing, which should be considered to be utilized in TFA. In this study, a novel time-frequency analysis method referred to as velocity guided chirplet transform (VGCT) is proposed. This method directly uses rotation speed signal to describe the instantaneous frequency of the basis functions, and the basis functions are constructed by numerical integration instead of analytic expression to match the harmonic components in vibration signals, which can achieve the best performance in violent non-stationary signal analysis. After that, a numeric simulation was given to test its performance and computational efficiency. Finally, this paper gave two experiment cases, which showed its applicability and advantage in the field of health management for the aerospace equipment.