Analysis and comparison of resonance compensation in dual-stage actuation system of HDDs

Dual-stage actuation system will be adopted in hard disk drives (HDDs) to meet the demand for higher radial recording density in the near future. The resonance of milli/micro-actuator in the dual-stage actuation system limits the improvement of the servo bandwidth. In this paper, three approaches of resonance compensation for dual-stage actuation system in HDDs, namely notch filtering, indirect adaptive compensation and structurally parallel compensation, are compared for the goal of extending the servo bandwidth. The characteristics and tradeoffs of each method is analyzed and compared in the same baseline control structure. It is shown that appropriate resonance compensation methods can increase the servo bandwidth considerably, and thus could increase the tracking accuracy with least changing to the servo controller in HDDs