| 摘要 |
PROBLEM TO BE SOLVED: To obtain a magnetic disk device which can be made thin and whose controllability is enhanced by a method wherein two series of estimation systems, i.e., the estimation system of the movement of a read/write head actuator and the estimation system of a disturbance which is applied to the read/write head actuator, are provided and the command value of a next segment is decided on the basis of outputs of the respective estimation systems. SOLUTION: A movement estimation system 110 is composed of a feedback circuit which simulates the operation of a voice coil motor VCM which is free of a disturbance and ideal with reference to the input of a command value 143. The actual VCM receives a command value 142, and it outputs a displacement signal via a burst decoder 141. In the movement estimation system 110, the difference signal between an own output displacement signal and the displacement signal from the burst decoder 141 is an internal feedback signal. As a result, a position estimated value and a speed estimated value via a buffer 117 and a buffer 118 are output as movement corrected values. A computing circuit 130 corrects a set value by using the position estimated value and the speed estimated value, and it generates the command value 142 of a next segment.
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