READ/WRITE POSITION CONTROLLER FOR PICKUP

摘要

PROBLEM TO BE SOLVED: To provide a read/write position controller and the like of high performance which can perform control at a high speed with high safety. SOLUTION: The read/write position controller has an error signal generator for generating an error signal of the read/write positions of a pickup; an actuator for changing the read/write positions; a servo-controller for driving the actuator by performing nonlinear and linear control of the read/write positions based on the error signal; a switch for switching the servo-controller from servo open-mode to closed-mode based on the error signal; and an adjuster for adjusting the gains of the nonlinear and linear control. The adjuster adjusts the gains so that the nonlinear control component is larger than the linear control component at the time of switching and the linear control component is larger than the nonlinear control component after the elapse of a predetermined time from the time of switching. Also, the adjuster adjusts the gains of the nonlinear and linear control such that the nonlinear control component is larger than the linear control component in the predetermined time after the disappearance of the defect on a recording medium is detected. COPYRIGHT: (C)2005,JPO&NCIPI