Method and apparatus for analyzing vibration of housing of disk device

Abstract

A method and an apparatus for analyzing the vibration of the housing of a disk device are disclosed, in which the residual vibration of the housing can be accurately detected for protection against vibrations by determining the transfer function of the rotational acceleration of the housing. The vibration of the housing of the disk device attributable to a head actuator built into a computer or constituting a disk device housed in a locker is detected in such a manner that a random seek current is supplied to the head actuator from an external source, the transfer function of the rotational acceleration of the housing obtained from at least n acceleration sensor mounted on the housing is determined for each frequency, the spectrum of the random seek current supplied to the head actuator is multiplied by the transfer function of the housing, the resulting product is integrated twice thereby to convert the rotational acceleration into a displacement, the converted value of displacement thus obtained is multiplied by the servo follow-up error characteristic of the head actuator thereby to determine the power spectrum of the residual vibration in the frequency domain. The power spectrum is subjected to an inverse Fourier transformation thereby to detect the oscillation of the head with respect to time.