HDD Servo Control Technologies - What We Have Done and Where We Should Go -
نویسنده
چکیده
Since 1986 when digital servo was introduced in mass production HDDs, various kinds of control theories have been applied to HDD servo system, and the performances had improved dramatically. A 3.5-inch HDD capacity, which was 251 MB in 1988, has 1,000,000 MB (1 TB) capacity in 2007. The Fast access (high quality motion control), very precise positioning (nanometer scale), and robustness against environment changes, various kinds of disturbances, and plant dynamics fluctuations, have been required in HDD servo system to achieve the capacity increase. In this paper, some of key topics of recent HDD servo research are described and an integrated servo mechanical design based on detail understanding of plant dynamics and disturbance is described in detail as one of recent outstanding activities to improve positioning accuracy.
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