Vibration control of a PZT actuated suspension dual-stage servo system using a PZT sensor

Structure resonance modes of the head stack and suspension assembly are one of the major limiting factors for head-positioning servo performance in hard disk drives. This paper discusses vibration suppressing control of a PZT actuated suspension based dual-stage servo system. A PZT trip on a PZT actuated suspension is utilized as a vibration sensor to control both the VCM actuator butterfly mode and the suspension sway mode. The vibration controller is designed using the H/sub /spl infin// control design method. Experiments show that an attenuation of 15 dB can be achieved for both the suspension sway mode and the VCM butterfly mode: The RMS of the head off-track motion due to air-flow excited vibration can be reduced by 30 % with the proposed vibration suppression control scheme.