| 摘要 |
PURPOSE:To suppress the oscillation of a fine actuator by comparing the output held just before the access operation of a detector, which detects the motion of the fine actuator, with the output during the access operation of this detector. CONSTITUTION:Just before the rough access operation due to a linear motor 4, a shake angle signal 100 of a galvanomirror is held by a sample and hold circuit 14 controlled by a rough access start signal 102 and becomes a lock angle signal 104. A lock angle deviation signal 106 obtained by subtracting the shake angle signal 100 of the galvanomirror from the lock angle signal 104 passes a compensating circuit 16 and a driver 18 to become a galvanomirror driving signal 108, and the galvanomirror 10 is so controlled that the lock angle deviation of the galvanomirror is zero. Since this control time is very shorter than the time required for the rough access operation due to the linear motor 4, the gain relations between the actual galvanomirror shake angle and the shake angle signal 100 are kept constant, and the galvanomirror shake angle is locked correctly at the shake angle just before the rough access during the rough access.
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