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Hard Disk Drive (hard + disk_drive)

Distribution by Scientific Domains
Engineering60%

Selected Abstracts

Long-span seek control system for hard disk drive without mode-switching

ELECTRICAL ENGINEERING IN JAPAN, Issue 3 2010
Shinji Takakura
Abstract In hard disk drives (HDD) there are two control modes: the head positioning control mode and the other is the seek control mode. In the head positioning control mode, a feedback controller is optimally designed to suppress disturbances. In the long-span seek mode, a velocity feedback control system is applied in order to move the heads fast. Thus, an HDD has multiple control systems, and the head is moved to the target position while changing from one control system to the other. However, changing the control system causes a discontinuous control signal, which activates the resonant mode of an actuator. Past methods can only decrease discontinuous control, and therefore a single control system that can be used for both a seek control mode and a head positioning control mode is necessary for a narrow track pitch. In the proposed method, the feedback controller is decomposed into an integrator and a phase compensator. The VCM model is updated by the output of the phase compensator, and the integrator and the output of the velocity feedback controller control the VCM. The validity of the proposed method was confirmed by numerical and experimental results using a miniature 2.5-inch hard disk drive. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 171(3): 51,60, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20935 [source]

Iterative learning control and repetitive control in hard disk drive industry,A tutorial

INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 4 2008
YangQuan Chen
Abstract This paper presents a tutorial on iterative learning control (ILC) and repetitive control (RC) techniques in hard disk drive (HDD) industry for compensation of repeatable runouts (RRO). After each tutorial, an application example is given. For ILC, a simple filtering-free implementation for written-in RRO compensation is presented. For the RC part, a new application of RC in dual-stage HDD servo is presented. Copyright © 2007 John Wiley & Sons, Ltd. [source]

A novel discrete-time sliding mode technique and its application to a HDD dual-stage track-seek and track-following servo system

INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 4 2008
G. Herrmann
Abstract A novel approach for the design of a discrete-time sliding mode controller is presented showing that the dynamics of a sliding-mode state-feedback controller can be designed using a singular LQR approach. The weighting of the control signal is set to zero and dead-beat behaviour for the sliding mode reaching dynamics is achieved. The reaching dynamics are modified when the states are a significant distance away from the sliding surface to avoid any high magnitude control action due to the partial dead-beat approach. The control law also takes into account the constraints on the actuator amplitudes and a stability analysis is presented using a discrete-time version of the Popov criterion. The control approach is demonstrated in conjunction with a recently developed large-span track-seeking and track-following method for dual-stage actuator systems in a hard disk drive (HDD). It is shown how the discrete-time sliding mode control scheme can be incorporated into the observer-based control system for the secondary actuator. Superior performance for the track-seeking and track-settling process is demonstrated using an existing practical set-up of a dual-stage HDD servo system. Copyright © 2007 John Wiley & Sons, Ltd. [source]

The co,evolution of technologies and institutions: a comparison of Taiwanese hard disk drive and liquid crystal display industries

R & D MANAGEMENT, Issue 3 2002
Chang Hung
In this paper, we examine the different evolutionary processes and outcomes of the hard disk drive and liquid crystal display industries in Taiwan. To this end, we make two general theoretical claims. First, that an appreciation of the globalization of technology is as important as national institutions in understanding industry development in catch,up economies such as Taiwan. Second, in addressing both industrial survival and failure, that national institutions can have either a positive or a negative impact on sectoral activities. Empirically, we show that, in Taiwan, rigid social institutions conflict with the hard disk drive technology. This conflict, in turn, produces obstacles to Taiwanese firms' search for new markets and skills in hard disk drives. On the other hand, Taiwan's institutional structures provide a source of technical efficiency and market opportunity for the emerging liquid crystal display trajectory. This, in turn, drives Taiwanese industry towards adopting new practices in the manufacture of liquid crystal displays. [source]