Measurement and modeling of quasi-rigid-body modes in the head actuator assembly

L. M. Xu, S. Zeng, N. Guo, R. M. Lin, C. M. Hu

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7 Citations (Scopus)


As the track density increases and the seeking time reduces, residual vibration problems become increasingly critical in the design and performance of hard disk drives. It is essential to further understand the dynamics of the head actuator assembly, such as the effect of pivot bearing. This paper studies the characteristics of quasi-rigid-body modes, which are most important in understanding the dynamic behavior of the head actuator assembly. Experimental results are presented in terms of the frequency response functions obtained in lateral and vertical direction excitation. Finite-element models are used to predict the quasi-rigid-body modes and their dependence on the stiffness of pivot bearing. A good agreement is obtained between the numerical prediction and measurement. It is shown that six quasi-rigid-body modes may exist, and two of these may lead to residual vibration and track misregistration in the frequency range of interest. The causes are likely the flexibility of the pivot-bearing system and the difference in the stiffness of the fivo bearings in the pivot-bearing system.

Original languageEnglish
Pages (from-to)141-150
Number of pages10
JournalJournal of Information Storage and Processing Systems
Issue number3
Publication statusPublished - Jul 2000
Externally publishedYes


  • Head actuator assembly
  • Pivot-bearing
  • Quasi-rigid-body mode
  • Vibration

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