Suppression of residual vibrations around the sampling frequency

We have developed the control method that can suppress the residual vibration around the sampling frequency in the sampled-data control system. This study has been based on shock response spectrum (SRS) analysis that handles the transient-state characteristics of mechanical resonances. The control method uses multi-rate notch filters that modify the acceleration input signals. The results of SRS analysis show that the multi-rate notch filter can decrease the amplitude of residual vibrations caused by the mechanical resonances around the sampling frequency. To show the validity of the proposed method, experiments were conducted on the sampled-data positioning control system of a head-positioning control system in a hard disk drive.