Automatic servo control gain compensation technique for hard disk drive

摘要

An automatic servo control gain compensation technique for a hard disk drive for minimizing the deterioration of the performance of a control system, while designing the control system to have a compensation adaptive capacity for variations of external variables includes: (a) receiving an input of a seek command, inputting a position signal varied according to movement of a head, and obtaining a current position and a current velocity by calibration, and finally obtaining a velocity error; (b) accumulating a value in the velocity obtained in step (a) and checking whether or not a seek distance by a seek command is within a proper range; (c) when checked at step (b) that the seek distance by the seek command is within the proper range, varying a control gain to be adapted to the characteristic variation by using the calibrated velocity error; (d) checking whether or not a current seek distance corresponds to a distance sufficient to obtain the error required for performing the automatic compensation depending on the variations of the control gain obtained in step (c); (e) checking whether or not the sum of the velocity obtained in step (a) exceeds a reference value, and then, upon the sum thereof exceeding the reference value, determining whether or not the system is to be updated; (f) storing a current target cylinder number from the result obtained in step (e), setting a clock during the automatic compensation, calibrating the characteristic variations of the control system, and adjusting the seek to update the control system; and (g) returning to the target cylinder stored and setting a flag.