Slider vibration analysis at contact using time-frequency analysis and wavelet transforms

Time-frequency analysis and wavelet transforms are employed to investigate transient contact dynamics at the head/disk interface of computer hard drives. Wavelet transforms are used to resolve multiple short consecutive contacts at high time resolution at high frequencies. The reassignment method is applied to the time-frequency distribution to enhance the time-frequency resolution, thereby allowing to resolve air-bearing and slider body frequencies simultaneously. The results indicate that strong impacts between slider and disk can lead to excitations of slider body and suspension vibrations. Finite element modal analysis of nano and pico glide sliders is found to be in good agreement with experimentally measured frequencies.