Browse Prior Art Database

Ramp Velocity Control for Loading Heads in a Direct Access Storage Device File

IP.com Disclosure Number: IPCOM000114770D
Original Publication Date: 1995-Jan-01
Included in the Prior Art Database: 2005-Mar-29
Document File: 2 page(s) / 62K

Publishing Venue

IBM

Related People

Erickson, KJ: AUTHOR

Abstract

A method to detect the velocity of a disk drive actuator as it loads the head(s) onto the disk(s) is described. This method is useful in very small Direct Access Storage Device (DASD) files where the traditional means of detecting the actuator velocity using back-Electromotive Force (EMF) measurement techniques does not work because the back-EMF voltages are too low to detect in the presence of electronic noise. This method not only provides for a more accurate load velocity measurement, and hence better load velocity control, but it also provides information regarding the position of the actuator on the load ramp, which is not available in the back-EMF methods.

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Ramp Velocity Control for Loading Heads in a Direct Access Storage
Device File

      A method to detect the velocity of a disk drive actuator as it
loads the head(s) onto the disk(s) is described.  This method is
useful in very small Direct Access Storage Device (DASD) files where
the traditional means of detecting the actuator velocity using
back-Electromotive Force (EMF) measurement techniques does not work
because the back-EMF voltages are too low to detect in the presence
of electronic noise.  This method not only provides for a more
accurate load velocity measurement, and hence better load velocity
control, but it also provides information regarding the position of
the actuator on the load ramp, which is not available in the back-EMF
methods.

      Head load ramps in disk drives are typically made of some type
of plastic-based material.  The load ramp material can be impregnated
with a conductive material such that the load ramp becomes a
resistive device.  It is also possible to construct the load ramp
from a conductive polymer material, or coat it with such a material
to achieve similar resistive characteristics.

      The load ramp is isolated from the file casting with an
insulating device, such as a washer, and is connected to a current or
voltage source on the file electronics card.  When the actuator is
positioned such that the head load tang (the piece of metal extending
from the head suspension assembly used to ride the ramp to effect the
head load/unload operation) is on the ramp, then electrical current
can flow from the sour...