03-11-2012, 05:10 PM
A Nonlinear PID Servo Controller for Computer Hard Disk Drives
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[attachment=38121]
Abstract-
A nonlinear PID scheme is proposed as an efficient
hard disk drive servo controller, reducing the settling time and
lowering the required control effort. The controller is capable
of increasing (decreasing) damping effect when the system
output is moving away from (towards) the desired track. This
is carried out by utilizing a derivative action tuned by a
nonlinear function to provide the system with the needed level
of damping. Simulation results, including step function
response, control signal history, robustness in terms of the
influence of a rate limiter, and a disturbance rejection
capability are presented.
Introduction
The advancement in the hard disk drive data storage
technology has been characterized with the continuous and
dramatic growth in areal density. Magnetic media have now
the potential capability of storing well above 100 Gb/in2 of
data. This has necessarily led to narrowing the track width
down to the sub-micron level. Hence, there has been a
continuous need for an extremely accurate track following
mechanisms, which provide smoother commands to the
controlled plant and a higher control bandwidth, while
preserving a low sampling rate.
A number of modern control approaches were tried to realize
precise positioning. Of these, the linear quadratic gaussian
methodology [1-3], the robust H
[attachment=38120]
[attachment=38121]
Abstract-
A nonlinear PID scheme is proposed as an efficient
hard disk drive servo controller, reducing the settling time and
lowering the required control effort. The controller is capable
of increasing (decreasing) damping effect when the system
output is moving away from (towards) the desired track. This
is carried out by utilizing a derivative action tuned by a
nonlinear function to provide the system with the needed level
of damping. Simulation results, including step function
response, control signal history, robustness in terms of the
influence of a rate limiter, and a disturbance rejection
capability are presented.
Introduction
The advancement in the hard disk drive data storage
technology has been characterized with the continuous and
dramatic growth in areal density. Magnetic media have now
the potential capability of storing well above 100 Gb/in2 of
data. This has necessarily led to narrowing the track width
down to the sub-micron level. Hence, there has been a
continuous need for an extremely accurate track following
mechanisms, which provide smoother commands to the
controlled plant and a higher control bandwidth, while
preserving a low sampling rate.
A number of modern control approaches were tried to realize
precise positioning. Of these, the linear quadratic gaussian
methodology [1-3], the robust H