Adaptive feedforward cancellation with damping control system in head positioning systems of HDDs

Abstract

Adaptive feedforward cancellation (AFC) with a damping control system has been developed to improve the head-positioning accuracy in hard disk drives (HDDs). There are various disturbances that reduce the head-positioning accuracy in a head-positioning system. The control system must compensate for these disturbances to improve the head-positioning accuracy. In addition, the robustness of the control system should be considered to realize stable operation for a mass-produced product such as HDDs. The proposed AFC updates a forgetting factor that corresponds to a damping factor in the adaptive algorithm to minimize the position error signal in real-time, and it can optimize the characteristics of the control system according to individual variations. We verified effectiveness of the proposed AFC in the HDD benchmark model. It was confirmed that the proposed AFC can adequately compensate for the vibration caused by flow-induced vibration defined in the benchmark model.