Dynamic magnetic information storage or retrieval – Automatic control of a recorder mechanism – Controlling the head
Reexamination Certificate
1998-09-21
2001-11-20
Sniezek, Andrew L. (Department: 2651)
Dynamic magnetic information storage or retrieval
Automatic control of a recorder mechanism
Controlling the head
C360S078090
Reexamination Certificate
active
06320721
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
This invention relates generally to control systems and more particularly to a method and apparatus for controlling a voice control motor in a hard disk drive.
BACKGROUND OF THE INVENTION
Mass storage devices such as hard disk drive systems generally include a magnetic storage media for storing information, a spindle motor for rotating the storage media, a magnetic read/write head for reading information from or writing information to the magnetic storage media, and an actuator for positioning the read/write head over the storage media. A control system associated with the actuator controls the movement of the actuator.
An actuator in a hard disk drive system places the read/write head in an appropriate location over the magnetic storage media before a read or write operation occurs. Moving the read/write head takes time, though, and during that time the mass storage device cannot store or retrieve information. The average time required for the actuator to move the read/write head is referred to as the “seek time” of the storage device. Shorter seek times are preferable to longer seek times.
In moving the read/write head from one position to another, a conventional control system is modeled as a second order system. A problem with conventional control systems is that the second order system model produces a seek time that may be too long for modern applications. The time it takes for the read/write head to move from position to position is longer than desired, which causes the storage device to operate at a lower level of performance than desired.
SUMMARY OF THE INVENTION
Accordingly, a need has arisen for an improved method and apparatus for controlling a voice control motor in the actuator of a hard disk drive system. The present invention provides a method and apparatus for controlling a voice control motor of a hard disk drive system that addresses shortcomings of prior systems and methods.
According to one embodiment of the invention, a method of moving a device from a first position to a second position by an actuation system includes moving the device in response to providing a control signal having a first amplitude for a first time period. The method also includes, immediately after the first time period, moving the device in response to providing a control signal having a second amplitude for a second time period, the device having a nonzero velocity after the second time period. The nonzero velocity has a magnitude that allows the device to coast to, and stop at, the second position after the second time period without receiving a control signal.
According to another embodiment of the invention, a hard disk drive system includes a disk storage media for storing information and a head for recording and reproducing data in the disk storage media. The hard disk drive system also includes an actuation system for positioning the head relative to the disk storage media and a control system for controlling the actuation system. The actuation system is further operable to move the head from a first position to a second position in response to receiving, from the control system, a control signal having a first amplitude for a first time period, immediately after the first time period receiving, from the control system, a control signal having a second amplitude for a second period of time, and, immediately after the second time period, receiving no control signal. The control signals, in combination with actuation system, generate a velocity and an acceleration for per head that allows the head to coast to the second position after the second time period.
Embodiments of the invention provide numerous technical advantages. For example, in one embodiment of the invention, the device moves from the first position to the second position in less time than with convention control systems. Another advantage of one embodiment of the invention is that the seek time of the device is shorter, resulting in more operations performed by the device in a shorter amount of time. Yet another advantage of one embodiment of the invention is that the overall performance of the device is improved. In another embodiment of the invention, a hard disk control system of a hard disk drive system can easily transition from seek mode, where a read/write head moves to a new position, to tracking mode, where the read/write head is kept on track. Finally, the present invention can be implemented in any system that can be modeled as a third order transfer function.
Other technical advantages are readily apparent to one skilled in the art from the following figures, descriptions, and claims.
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Heaton Mark W.
Magee David P.
Sniezek Andrew L.
Texas Instruments Incorporated
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