A Review of Synchro-Transform Method in Mechanical Fault Diagnosis

Many Synchro-Transforms (ST) variants are being actively developed recently to break through the limitations of the traditional time–frequency analysis (TFA) that susceptible to the Heisenberg uncertainty principle. They achieve high-precision time–frequency representation (TFR) by “squeezing” or extracting the energy around the time–frequency (TF) ridges in either the time direction or the frequency direction of a TF spectrum. With the continuous refinement of synchro-transform methods, the synchro-transform methods and its variants have greatly facilitated the application of TFA methods in different fields. This paper provides a comprehensive review of recent achievements on ST methods in the field of mechanical fault diagnosis. The state-of-the-art in TFA method based on ST is summarized. The current challenges in the field of the ST in mechanical fault diagnosis are discussed, which will provide insights into the development and utilisation of the ST in the field of mechanical fault diagnosis.