Diagnostics of static unbalance of single wheel of passenger car carried out on road

This paper presents a method of identification of non-homogeneity or static unbalance of the structure of a car wheel based on a simple road test. In this particular method the detection of single wheel unbalance is made with help of acceleration sensor fixed on windscreen. Location of the sensor is convenient for handling an autonomous device used for diagnostic purposes. The goal is to select appropriate transformations and procedures in order to determine wheel unbalance. In this investigations regular and short time Fourier transform was used as well as wavelet transform. It was found that Fourier transforms utilized here are proper for static condition (constant velocity) but the results proves that the wavelet transform is more suitable for diagnostic purposes because of its ability to produce clearer output even if car accelerates or decelerates.