| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a head-unlatching control method in which the head speed in the unlatching operation is stabilized so as to prevent an error and in which the succeeding operation is controlled favorably by a method wherein the unlatching current is regulated on the basis of the result of the computation/of the head speed by making use of servo information which is read out from the head during the execution of the unlatching operation. SOLUTION: A servo synchronizing operation and a speed check are executed in an acceleration period and a deceleration period. When either the head speed > the speed limit value or the unlatching deceleration current > the minimum value which can not perform the servo synchronizing operation, the unlatching deceleration current is decreased stepwise byΔbrake, e.g. 12mA, a head deceleration operation is performed slowly, and a deceleration control operation is continued. When the above three conditions are all satisfied, the unlatching current is set forcedly to '0'. The head speed can be expressed byΔTrack/T (where T represents the sampling cycle, andΔTrack represents the distance between the previous track and the present there).</p> |
