Open loop acceleration/deceleration control for disk drive stepper motors
OwnerLawrence M. Bryantinventor
Life of this patent
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Abstract
An open loop controller for the stepper motor of a disk drive actuator is programmed to supply pulse width modulated drive voltages for energizing and de-energizing successive phases of the stepper motor at controlled rates during the initial and final phases of each actuator seek, thereby controlling the acceleration and deceleration profiles of the actuator to reduce its mid-frequency resonance, settling time and position hysterysis.
Claims11
In a disk drive having an actuator for aligning a read/write head with a selected data track, and a unipolar stepper motor for driving said actuator in response to seek commands identifying the direction and number of steps said actuator is to be moved to complete respective seeks;
- the improvement comprising an open loop programmed controller for energizing and deenergizing selected phases of said stepper motor in proper sequence to execute said seeks,
- said controller being programmed to apply predetermined length bursts of width modulated complementary drive voltage pulses to the phases of said motor which are energized and de-energized as said seek is being initiated and completed, whereby the acceleration and deceleration profiles of said actuator are controlled.
In a disk drive having an actuator for aligning a read/write head with a selected data track, and a bipolar stepper motor for driving said actuator in response to seek commands identifying the direction and number of steps said actuator is to be moved to complete respective seeks;
- the improvement comprising an open loop programmed controller for reversing the energization of selected phases of said stepper motor in proper sequence to execute said seeks,
- said controller being programmed to apply predetermined length bursts of width modulated drive voltage pulses to said selected phases of said motor while said seek is being initiated and completed, whereby the acceleration and deceleration profiles of said actuator are controlled.
Dependencies are inferred from the claim text.