| 摘要 |
PURPOSE:To improve the precision of follow-up trucks for read and write actions preventing the vibration of a head by providing a switching method in a closed loop for a servo and controlling a loop gain automatically according to the action condition. CONSTITUTION:A position detector 5 detects the difference of the vibration between each truck signal in an output 4 of a servo head 3, and a position error detecting circuit 6 obtains the deviation of a head from the center of the truck on the basis of the amplitude difference and generates a control signal according to the value. This signal drives a voice coil motor 9 through a voice coil driving circuit 8 after operations such as a proportion, advance and delay are carried out by a compensation circuit 7, and a head 3 installed on an arm 10 is moved to the central position of each truck. On the compensation circuit 7, a switching means 11 is provided to increase the gain in the conpensation circuit 7 at the read and write action and to decrease it on the waiting according to signals from a control circuit 12. |
