Seeking control apparatus and method for disk drives, using slew-rate limit for control output

Abstract

The purpose of the present invention is to provide a method and an apparatus for seeking-control for disk drives, in which (i) the step current waveform at the start of speedup or at the switching from speedup to slowdown is transformed into a current waveform by which the mechanical resonance of the disk drive is difficult to be excited; (ii) the lowering of tracking accuracy is prevented; and (iii) the effective seek time being measured from the seek start up to the time at which the writing or reading of the disk becomes possible can be shortened. The seeking control apparatus for disk drives according to the present invention comprises a reference velocity generator for generating a reference velocity which is defined as a function of the number of residual tracks; a subtracter for detecting a velocity difference between a moving velocity of a read-write device of a disk drive to be controlled and the reference velocity, and outputting the detected difference; a proportional amplifier for amplifying the output from the subtracter; a slew-rate limiter for limiting a rate of change of the control output from the proportional amplifier lower than a predetermined level, and outputting a limited output; and a power amplifier for amplifying the output from the slew-rate limiter and outputting positioner current.

Dependencies are inferred from the claim text.