Reduction of flow-induced suspension vibrations in a hard disk drive by dual-stage suspension control

Teerhuis, Arjan; Cools, S.J.M.; Callafon, Raymond A. de

doi:10.1109/tmag.2003.815441

Cited by 7 publications

(5 citation statements)

References 8 publications

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“…Progress in areal storage density of a HDD can be accomplished by using a dual-stage actuator system, in which a high-bandwidth and highly accurate micro-actuator (MA) is used in combination with a traditional Voice Coil Motor (VCM) to perform the read/write tasks over the data track (Li and Horowitz, 2002;Li et al, 2003;Teerhuis et al, 2003). The use of dual-stage actuator systems has received great attention from the servo design community and an overview of the literature can for example be found in (Mamun et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Fixed Order Pq-Control Design Method for Dual-Stage Instrumented Suspension

Graham

Oosterbosch

Callafon

2005

IFAC Proceedings Volumes

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To achieve frequency separation between actuators of a dual-stage servo actuator system in a hard disk drive, the PQ control design method can be used. In the PQ method, the servo controller is designed by focusing on structural interference of the actuators. This paper provides a specific parametrization for fixed order feedback controllers used in the PQ-method for which the structural interference between actuators can be minimized. The proposed control design method is applied to a dual-stage instrumented suspension, where the additional sensor of the instrumented suspension is used to attenuate high frequency disturbance caused by windage turbulence in a hard disk drive.

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Section: Introductionmentioning

confidence: 99%

Fixed Order Pq-Control Design Method for Dual-Stage Instrumented Suspension

Graham

Oosterbosch

Callafon

2005

IFAC Proceedings Volumes

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“…Other ways to reduce FIV include miniaturizing the HGA [15], and by active suspension such as a piezo-electric dualstage actuator [16]. The use of disk dampers [17] and the inserting of vibration isolators into HDD cavities [18] are also popular proposed ways of minimizing the effect of FIV.…”

Section: B Fiv Mitigationmentioning

confidence: 99%

Structure Optimization Study of Hard Disk Drives to Reduce Flow- Induced Vibration

Ng¹

2011

TONUMJ

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Abstract:In this paper, the effects of two flow-induced vibration (FIV) mitigation components on hard disk drive (HDD) airflow, vortex splitters and flow diverters, were verified. The edges of the components were also modified by filleting and the resulting effect on airflow determined. A perspective review on HDDs and their operation, and the mechanism and mitigation of FIV was discussed. Three suitable turbulent models from the commercial fluid flow solver FLUENT were briefly compared. A preliminary study was then carried out on a simplified HDD model to determine the mesh fineness required in HDD turbulent flow simulation in order to obtain accurate results. Another study was done to compare between the RNG k-and LES turbulent models in FLUENT. A full 3.5 inch commercial HDD model was used and results indicated that the LES model was suitable for turbulent flow modelling of a HDD. Lastly, flow simulation of three HDD models with different FIV mitigating features was carried out. Results showed that flow diverters are effective in reducing airflow turbulence in HDD for Re of 12.5x10 4 . The modification and filleting of component edges to make them more aerodynamic streamlining was shown to be less effective but further studies should be done to conclude on the effectiveness of filleting. An optimized HDD structure which includes both vortex splitters and flow diverters, with the filleting of component edges recommended but not mandatory was proposed.

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“…In continuous time, such transfer functions can be expressed as (3) where contains the modes of the plant dynamics that can be modeled with certainty and contains the uncertain modes of the plant dynamics, which will be modeled by structured parametric uncertainties. In our case, since most of the uncertainty involves resonance modes, can be factorized by a product of second order transfer functions with uncertain coefficients (4) where is the total number of uncertain modes, and the superscript is used to index each uncertain mode. The uncertain coefficients in (4) are assumed to be affine functions of constant but unknown perturbations (5) where are the nominal values of the coefficients, are constant weighting coefficients, and are structured perturbations of unity magnitude.…”

Section: B Modeling Parametric Structured Uncertaintymentioning

confidence: 99%

“…In such a servo system a high-bandwidth and highly accurate micro-actuator (MA) is used in combination with a traditional voice coil motor (VCM) to position the read/write head on the slider over the data track [1]- [4]. While most high density demonstrations are achieved under well-conditioned laboratory environments, the servo system in a commercial HDD is subjected to inconsistencies due to manufacturing tolerances.…”

mentioning

confidence: 99%

Robust dynamic modeling and control of dual-stage actuators

2006

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In a hard disk drive with a dual-stage actuator the standard rotary actuation of the voice coil motor (VCM) is combined with an additional micro-or milli-actuation to accomplish high-bandwidth and highly accurate track following. For extremely high density recording, the servo control algorithm designed for a specific dual-stage actuator needs to maintain high performance track following in lieu of external disturbances and uncertainties in the dynamic response induced by product manufacturing tolerances. Essential in the robust design of a servo control algorithm is to bound these uncertainties and design a robust track following servos accordingly. In this paper, we present an experiment based methodology to characterize and bound the uncertainties in the dynamic response of a dual-stage actuator in the form of an uncertainty model. Subsequently, the uncertainty model is used for the analysis and synthesis of a robust dual-stage servo controller that is able to optimize position error variance in the presence of uncertainty information.

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Reduction of flow-induced suspension vibrations in a hard disk drive by dual-stage suspension control

Cited by 7 publications

References 8 publications

Fixed Order Pq-Control Design Method for Dual-Stage Instrumented Suspension

Fixed Order Pq-Control Design Method for Dual-Stage Instrumented Suspension

Structure Optimization Study of Hard Disk Drives to Reduce Flow- Induced Vibration

Robust dynamic modeling and control of dual-stage actuators

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