Browse Prior Art Database

Servo Angular Accelerometer for theta dotdot Detection and Measurement

IP.com Disclosure Number: IPCOM000104851D
Original Publication Date: 1993-Jun-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Sri-Jayantha, M: AUTHOR

Abstract

A low-cost voice coil motor (VCM)-based angular accelerometer configuration is disclosed for theta dotdot detection particularly for portable DASD's as a target system. For laptop DASD application, the need to detect angular motion is important in order to provide improved shock and vibration protection during operating condition.

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Servo Angular Accelerometer for  theta dotdot  Detection and Measurement

      A low-cost voice coil motor (VCM)-based angular accelerometer
configuration is disclosed for  theta dotdot  detection particularly
for portable DASD's as a target system.  For laptop DASD application,
the need to detect angular motion is important in order to provide
improved shock and vibration protection during operating condition.

In present disk drives the read/write (R/W) heads are positioned
using sector servos which have the ability to detect off-track
movements at discrete time instants, but in between samples they do
not have sufficient information to detect external shock or transient
vibration.  Ignorance about head position in between samples could
result in loss of data integrity, particularly during write
operation.  A low-cost angular acceleration sensor can provide analog
information that can help detect transient rotational movement or
measure quiescent vibration.

     There is prior art in detecting "acceleration" to protect an
operating file from shock.  Various scenarios have been considered
such as a file-free fall detection.  However, the detection of
angular acceleration has not been treated as the mechanism that would
cause data failure.  Further, no low-cost sensor has been proposed.
A well balanced rotary actuator for R/W heads is sensitive mostly to
inplane angular acceleration components.  Angular accelerometers are
used in aerospace instrumentation...