| 摘要 |
PROBLEM TO BE SOLVED: To execute stable speed control by forming a speed signal in accordance with a tracking error signal, forming the speed error signal corresponding to a difference between the speed signal and a prescribed constant speed, extracting the low-frequency range signal of the speed error signal to determine a speed error low-frequency signal and feeding and driving a transferring means according to this speed low-frequency range signal. SOLUTION: A speed error forming circuit 523 determines the difference between the pulse width signal PW corresponding to the feed speed of a present slider and the pulse width corresponding to the prescribed constant speed as a speed error component and supplies this speed error signal component as the speed error signal to an adder 525. An acceleration component forming circuit 524 determines the difference between the feed speed of the present slider and the feed speed of the previous time estimated in accordance with the pulse width signal PW as an acceleration component and supplies this component as an acceleration signal Va to the adder 525. The acceleration component 524 sends the acceleration signal Va of a zero level to the adder 525 when a signal indicating the presence of abnormality is emitted from a pulse width abnormality detecting circuit 522.
|
