Head Positioning Control of a Hard Disk Drive Using H^|^infin; Control Theory

Hirata, Mitsuo; Liu, Kang‐Zhi; Mita, Tsutomu; Yamaguchi, Takashi

doi:10.9746/sicetr1965.29.71

Cited by 31 publications

(19 citation statements)

References 3 publications

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“…We note that the sampling period of r = 5O[ps] is small enough for the hard disk drive used in this study and it has been used for the digital implementation of analog controllers [6]. …”

Section: Controller Designmentioning

confidence: 99%

High performance digital servo design for HDD by using sampled-data H/sub /spl infin// control theory

Hirata

Atsumi²,

Nonami³

2000

6th International Workshop on Advanced Motion Control Proceedings

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I n the head positioning control of hard disk drives, a digital control is widely used. Therefore, i f a small sampling period could be used, the performance obtained by the digital controller is npt so deteriorated compared with the one obtained by the analog controller. However, in hard disk systems, the sampling period cannot be chosen arbitrary small. Because it is determined by the other factor which is nothing to do with control requirements in almost cases. I n this paper, we apply the sampled-data H , control synthesis to the head positioning control of the hard disk drive. This method enable us to design a desirable digital controller directly by taking into account of intersampling behaviors. Experimental results show that a good following performance can be achieved by the long sampling period.design a desirable robust digital controller by taking into account of inter-sampling behaviors and to evaluate the limitation of the performance attainable in sampleddata feedback control with a specified sampling period. Hence, we can also know the maximum sampling period which could achieve specified performances.In this paper, we apply the method of the sampleddata H , control to the robust control of the hard disk drive. At first, we discuss the construction of the generalized pli311t which achieves the robust stability for an unmodeled dynamics and the nominal performance to a disturbance attenuation. By using this generalized plant, a digital. H , controller is directly obtained by using the sampled-data H , control theory. The obtained performance of the sampled-data H , controller is compared with that of the continuous-time based controller by experiments and we show the effectiveness of our proposed met hod.

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“…We note that the sampling period of r = 5O[ps] is small enough for the hard disk drive used in this study and it has been used for the digital implementation of analog controllers [6]. …”

Section: Controller Designmentioning

confidence: 99%

High performance digital servo design for HDD by using sampled-data H/sub /spl infin// control theory

Hirata

Atsumi²,

Nonami³

2000

6th International Workshop on Advanced Motion Control Proceedings

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“…These methods were extended by Maciejowski [13] into discrete time LQG/LTR, which was applied later to design a tracking controller for compound (dual stage) disk drive actuator system by Yen et al [22] and Weerasooriya and Phan [20]. Based upon the frequency domain specifications on bandwidth and stability margins, Hirata et al [9] applied the method of modern H ∞ control to synthesize a head positioning servo system in HDD. Since the system has two poles at the origin, the mixed sensitivity minimization problem in H ∞ controller synthesis cannot be solved directly and has to be dealt with a priori by adjusting the design specifications in order to satisfy the numerical assumptions in the design [2,4,9].…”

Section: Introductionmentioning

confidence: 99%

“…Based upon the frequency domain specifications on bandwidth and stability margins, Hirata et al [9] applied the method of modern H ∞ control to synthesize a head positioning servo system in HDD. Since the system has two poles at the origin, the mixed sensitivity minimization problem in H ∞ controller synthesis cannot be solved directly and has to be dealt with a priori by adjusting the design specifications in order to satisfy the numerical assumptions in the design [2,4,9]. This paper presents the design and real-time implementation of a robust track following HDD servo control system using a multi-objective evolutionary algorithm (MOEA) toolbox [16,17].…”

Section: Introductionmentioning

confidence: 99%

Evolutionary design and implementation of a hard disk drive servo control system

et al. 2006

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The ever increasing demand for higher storage capacity and smaller magnetic hard disk drives have driven the need of developing a high performance head positioning servo control system. To meet the challenge, this paper presents the design and real-time implementation of a robust two-degree-of-freedom servo system for physical 3.5-in. hard disk drive with single voice-coil-motor actuator using a multi-objective evolutionary algorithm toolbox. Besides the simplicity in controller structure, such an evolutionary servo control system is capable of meeting various performance specifications of hard disk drives in both the time and frequency domains. It is shown that the servo system optimally moves the magnetic head onto the desired track with minimal control effort, and keeps it on the track robustly against plant uncertainties or runout disturbances. Validation results of the evolutionary servo control system are compared with classical PID and RPT controllers, which show excellent closed-loop response and robustness in the face of practical perturbations in HDD.

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“…Robust control techniques such as H ∞ control are effective when the plants have uncertainty. In H ∞ control, robust stabilization can be achieved with respect to additive and multiplicative perturbations [1]. The gain of the complementary sensitivity function must be reduced in the frequency range where modeling errors exist, which is similar to the gain stabilization approach.…”

Section: Introductionmentioning

confidence: 99%

“…In particular, handling of the lowest-order resonance modes (primary resonance modes) is important to achieve high-bandwidth design. Therefore, control performance depends strongly on how such modes are stabilized [1,2].…”

Section: Introductionmentioning

confidence: 99%

High‐bandwidth design of hard disk control system using H_∞ control with feedback‐type uncertainty

Hirata

Hasegawa

2010

Electrical Engineering Japan

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SUMMARYIn hard disk drives, it is important to enlarge the control bandwidth in order to shorten the track pitch for larger data capacity. However, it is difficult for the H ∞ control method to increase the control bandwidth if the mechanical resonance modes have uncertainty. This is because the robustness of the H ∞ control method is assured by the small-gain theorem for additive or multiplicative perturbation and the control bandwidth is limited by the uncertainty. In this study, we propose an H ∞ control method for high-bandwidth design by introducing a new uncertainty model with a feedforward and a feedback path in order to reduce the conservatism of robust design. The effectiveness is shown by numerical simulations.

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Head Positioning Control of a Hard Disk Drive Using H^|^infin; Control Theory

Cited by 31 publications

References 3 publications

High performance digital servo design for HDD by using sampled-data H/sub /spl infin// control theory

High performance digital servo design for HDD by using sampled-data H/sub /spl infin// control theory

Evolutionary design and implementation of a hard disk drive servo control system

High‐bandwidth design of hard disk control system using H_∞ control with feedback‐type uncertainty

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Head Positioning Control of a Hard Disk Drive Using H^|^infin; Control Theory

Cited by 31 publications

References 3 publications

High performance digital servo design for HDD by using sampled-data H/sub /spl infin// control theory

High performance digital servo design for HDD by using sampled-data H/sub /spl infin// control theory

Evolutionary design and implementation of a hard disk drive servo control system

High‐bandwidth design of hard disk control system using H∞ control with feedback‐type uncertainty

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High‐bandwidth design of hard disk control system using H_∞ control with feedback‐type uncertainty