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Displacement Amplification Recovery for Sensorless Spindle Motor Startup

IP.com Disclosure Number: IPCOM000102988D
Original Publication Date: 1990-Apr-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 68K

Publishing Venue

IBM

Related People

Erickson, KJ: AUTHOR [+2]

Abstract

A displacement amplification recovery method for sensorless spindle motor startup applies a means of overcoming startup stiction problems to the sensorless method of spindle control and works by solving the problem of no position feedback.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 54% of the total text.

Displacement Amplification Recovery for Sensorless Spindle Motor Startup

      A displacement amplification recovery method for sensorless
spindle motor startup applies a means of overcoming startup stiction
problems to the sensorless method of spindle control and works by
solving the problem of no position feedback.

      Overcoming stiction is accomplished by utilizing a displacement
amplification (also known as torque amplification) technique that
generates forces at the head-disk interface that are much higher than
the rote forces generated by the spindle motor alone.  Displacement
amplification works by exciting the mechanical system around the
head-disk interface at the natural resonant frequency of that system.
It does this by pulsing a current into the motor at a predetermined
frequency, which causes the system to rock back and forth, allowing
the accumulation of input energy that generates the forces required
to overcome the stiction forces.

      Previously, displacement amplification has been implemented
only on spindle systems utilizing Hall sensors for spindle position
feedback.  Position feedback is required in order to select the
output current phase to the motor that results in the highest torque.
Any other output current phase does not generate sufficient torque
for displacement amplification to take place.  With the advent of
spindle systems that do not utilize Hall sensors, i.e., sensorless
spindles, a problem of not knowing which output...