Adaptive compensation of contact-induced vibration in high density HDD servo systems using peak filter method

In this paper, a phase lead peak filter (PLPF) design method is adopted to adaptively compensate contact-induced vibration (CIV) in high density hard disk drive (HDD) servo systems. Such kind of vibration is a new vibration source due to continuous contact of the read/write head with the media in HDDs, and its main characteristics are the time-varying phase and magnitude and the narrow-band frequency spectrum. In the PLPF based controller, a baseline feedback controller is first employed to stabilize the servo loop and add-on peak filters are then connected in parallel with the baseline controller to further suppress the specific vibrations. Meanwhile, a frequency identification algorithm is plugged-in simultaneously to meet the variation of central frequency of CIV. The proposed CIV compensation scheme has simple control structure, is capable of dealing with multiple vibration modes that may not be within the bandwidth of open-loop transfer function, and possesses remarkable robustness to CIV change. In the end, the performance of the proposed method in CIV compensation is validated by simulation and experiment.