Effect of ramp profile and spindle speed on head-disk contact during rotary load/unload

Levi, P.G.; Talke, Frank E.

doi:10.1109/20.281342

Cited by 8 publications

(2 citation statements)

References 5 publications

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“…In the non-CSS mode operation, the profile for loading/unloading is very important. This is due to the flexibility of the suspension which is easily subjected to extreme disturbances such as air flow [9][10][11][12]. In this paper, two types of profiles have been tested in order to improve the loading/unloading performance: harmonic and cycloidal.…”

Section: Controller Designmentioning

confidence: 99%

Non-contact start/stop motion control of HDD suspension using shape memory alloy actuators

Lim¹,

Park²,

Choi³

et al. 2001

Smart Mater. Struct.

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In hard disk drives (HDD), an important issue related to increased storage density is the tribological problem of the head/disk interface. The conventional head gimbal assembly (HGA) of the HDD is used in a contact start/stop mode which results in wear particles and debris. This may cause a serious problem for the read/write function. In this paper, we propose a new type of suspension featuring a shape memory alloy (SMA) actuator in order to prevent friction between the head (slider) and disk. As a first step, a finite element analysis is undertaken to investigate modal characteristics of the proposed HGA. Using the principal modal parameters, such as natural frequency, a control system model is established and a sliding mode control algorithm to achieve a non-contact start/stop (non-CSS) mode is formulated.The key control principle for accomplishing the non-CSS mode is that the control input is to be employed in the SMA actuator before the disk rotates, and is disconnected when the angular velocity of the disk is fully developed to achieve a certain flying height. In order to demonstrate the effectiveness of the proposed control system, a conventional HGA is modified to integrate the SMA actuator. The control algorithm is experimentally realized and controlled motions for the non-CSS mode are presented in the time domain.

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Section: Controller Designmentioning

confidence: 99%

Non-contact start/stop motion control of HDD suspension using shape memory alloy actuators

Lim¹,

Park²,

Choi³

et al. 2001

Smart Mater. Struct.

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“…The advantages and disadvantages of load/unload technology are present together, many researchers have studied on load/unload system. Levi et al [2] performed experiments to study the effects of the ramp profile and the spindle speed on head-disk. Yonghyun et al [3] presented effect of mechanical parameters for loading contact and instability in HDD, how the height differences cause the loading contact and instability through the relation among mechanical parameter height of the HSA, the ramp and the disk.…”

Section: Introductionmentioning

confidence: 99%

An Experimental Study of Fly Height by Load/Unload in Magnetic Recording

2016

International Conference on Engineering Technologies and Big Data Analytics (ETBDA’2016) Jan. 21-22, 2016 Bangkok (Thailand)

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An experiment study of fly height was performed to observe how the head-disk spacing after loading-unloading the head from the ramp onto the disk on the spin-stand testing. The fly height of write and read operation were analyzed by calculated from the power applied. The heater resistance of write and read were collected during test. Results of the test 190,000 cycles of loading/unloading showed, the fly height of write increased more than the read. The fly height of all heads showed increasing trend. Observing the lube pick up on head and accumulation lube on the disk about 20%. The heater resistance of write and read were quite standing.

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Effect of load/unload process on friction/stiction and durability of head-disk interface

Tambe

Bhushan

2002

Microsystem Technologies

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Effect of various operating parameters viz. load/ unload speed, disk speed, ramp height, and disk dynamics on load/unload performance, friction/stiction and durability of a head-disk interface (HDI) were studied. Load/ unload performance was evaluated using acoustic emission signals and friction force measurements. The load/ unload performance was found to be better for higher load/unload durations, lower disk speeds and higher ramp heights. The effect of ramp height was studied for two different slider suspension designs. A slider suspension with 'A' type suspension design performed well for higher ramp heights. The slider with 'B' suspension design was not affected by a change in ramp height. Disk dynamics studies indicated how strongly HDI can be affected by disk vibrations and supported the effect seen by varying ramp heights. Durability tests revealed that the HDI deteriorated faster for lower ramp heights for a slider with 'A' type suspension design than for the slider with 'B' type suspension design. IntroductionDeveloping disk drive products with improved magnetic and tribological properties has been an ongoing process [1]. Stiction and start stop wear encountered in contact start-stop (CSS) technology and the need for texturing of the disk are a major hindrance to continual growth of storage capacity [2,3]. Head load/unload technology is an alternative to CSS technology that eliminates stiction and wear failure modes associated with CSS. In drives that use the load/unload technology, a lifting mechanism removes each head from the disk surface prior to power-down and returns the heads to the disk surface only after a sufficient rotation rate has been reached on the next start-up. As a result, head-to-disk contact and any other head-to-disk interaction is significantly reduced. Dynamic ramp load/ unload technology provides increased areal density due to the usage of super smooth disks, thinner protective overcoats, and lower flying heights. However, during the load/ unload process, slider and disk asperities come in intermittent contact with each other and this results in some interface wear. Additional tribological issues are the wear of the ramp used in load/unload. The effect of various drive parameters on interface wear induced as a result of multiple load/unload cycles is important to optimize drive performance and reliability.Simulation studies have been carried out to study effects of certain design parameters. Zeng and Bogy [4] reported the effect of loading speed and disk RPM on the loading process based on simulation results. Levi and Talke [5] performed experiments to study the effect of ramp profile and spindle speed on head-disk contact. However, to the best of the author's knowledge, no studies have been reported on the effect of ramp height and the role of slider suspension design on the load/unload performance. In a load/unload drive a certain amount of the disk real estate is consumed by the load/unload zone at the outer diameter (OD) of the disk (and inner diameter (ID) of the disk for ...

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Effect of ramp profile and spindle speed on head-disk contact during rotary load/unload

Abstract: The relative effect of ramp profile and

Cited by 8 publications

References 5 publications

Non-contact start/stop motion control of HDD suspension using shape memory alloy actuators

Non-contact start/stop motion control of HDD suspension using shape memory alloy actuators

An Experimental Study of Fly Height by Load/Unload in Magnetic Recording

Effect of load/unload process on friction/stiction and durability of head-disk interface

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