Optimization of track seeking pulse waveform in hard disk drives

Track access time is an important parameter for high performance hard disk drives (HDDs). Presently, the resonances of the head actuator assembly (HAA) caused by the pivot stiffness and mass of the HAA are becoming an even more urgent problem, since these resonances have become the main design factor which limits further reduction of track access time and improvement of the servo control bandwidth in HDDs. This paper investigates the influence of the driving pulse waveforms on residual vibrations and attempts to identify a seeking pulse waveform which will lead to very low residual vibrations. If an appropriately chosen waveform and time duration of the seeking pulse waveform is employed, very low track seeking residual vibrations and quick track access can be achieved. The method has been developed based on a conceptually simple, yet representative, HAA model. The effectiveness of the proposed method has been verified through extensive analytical calculations, finite element simulations and experimental testing.