ROTARY STORAGE DEVICE AND ITS CONTROL METHOD

摘要

PURPOSE: To provide a technique for attempting to maintain a servo lock state and to restore to a normal readout state even when a servo address mark(SAM) can not be detected. CONSTITUTION: In this device, when the SAM can not be detected, a dummy SAM is generated in timing when a servo lock is not released. When servo control processes in which the dummy SAM is used exceeds a fixed frequency by performing a servo interrupt control normally, the device starts its urgency brake control. In the urgency brake control, the moving direction of an arm is judged and current is made to flow through a VCM(voice coil motor) so that the arm is driven in a reverse direction. Moreover, feedback control is performed by using the output value of a back emf(electromotive face) circuit which is used in a loading/unloading mechanism.