Patent ID: 6819522
Filing Date: 2004-11-16
Classification: G11B

Abstract:
A positioning control apparatus for moving a head that conducts recording and/or reproducing on a magnetic recording medium to a target position, said positioning control apparatus comprising:a trajectory generation unit for calculating a seek time required to move the head to a given target position, and a position trajectory and a velocity trajectory within the seek time every 2Ts, Ts being a sampling period of a position signal detected by a head position detection unit; a rigid body model and a dead time model of a head system ranging from outputting of a head drive signal to outputting of a detected position signal, inclusive of a head drive unit; a model control unit for calculating first and second model feedback control signals every 2Ts so as to cause a rigid body model position and a rigid body model velocity calculated by using said rigid body model to coincide respectively with the position trajectory and the velocity trajectory at a next sampling time point of the position signal, Ts being the sampling period of the position signal; a position control unit for calculating a feedback control signal based on a deviation between a model position for position feedback calculated by using said rigid body model and said dead time model and the detected position signal; a saturation detection unit for effecting detection to determine whether a drive current flowing through the head drive unit is saturated; and a switching unit for setting an input control signal equal to the first model feedback control signal at an even-numbered sampling time point of the position signal, setting the input control signal equal to the second model feedback control signal at an odd-numbered sampling time point of the position signal, responding to the drive current being judged by said saturation detection unit to be not saturated by setting a model input of said rigid body model equal to the input control signal and outputting a sum of the feedback control signal calculated by said position control unit and the input control signal to the head system as the head drive signal, and responding to the drive current being judged to be saturated by setting the model input of said rigid body model equal to a signal obtained by subtracting the feedback control signal calculated by said position control unit from a head acceleration corresponding to the drive current and outputting the input control signal or the head acceleration to the head system as the head drive signal.