| 摘要 |
PROBLEM TO BE SOLVED: To improve the positioning precisions without spoiling the stability of the control system in a magnetic disk drive even in a frequency exceeding the control band and the main resonant frequency, and in a frequency where the open loop phase characteristics become unstable. SOLUTION: This magnetic disk drive has a controller 28 to control the objects 27 including the magnetic head and actuators based on the given target position signals 24 and the reproduced position signals 20. When the controller 28 is connected with the objects 27, if there are resonant characteristics of other frequencies in the open loop transmission characteristics other than the mechanical resonant frequency of the objects and the frequencies in the resonant characteristics are higher than the frequency where the open loop transmission characteristics become 0dB, the phase of the open loop transmission characteristics becomes arctangent ((Rop+1)/Iop) in the frequencies of the resonant characteristics, when the coordinates of the vector locus of the open loop transmission characteristics are represented by (Rop, Iop) in the frequencies of the resonant characteristics. The controller is built as mentioned above. COPYRIGHT: (C)2006,JPO&NCIPI
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