| 摘要 |
PROBLEM TO BE SOLVED: To avoid the instability in the control due to observer processing at the time of mode transition or addition of disturbance from outside. SOLUTION: An optical disk unit is provided with: an actuator 4 that moves a beam spot that is formed by an optical head 2 on an optical disk 1 to recording surfaces 1a, 1b; position control portions 8, 9 that control a position of the beam spot based on the output signal of the optical head; a disturbance estimation observer 11 relating to the actuator; and a summing circuit 10 that takes a sum of the output of the position control portions and the output of the observer, so as to drive the actuator based on the output of the summing circuit. The optical disk unit further is provided with: a system controller 7 that turns the observer on and off; a LPF 12 that attenuates the high-frequency components of the output of the observer and retains the final value of the observer when the observer is turned off; and a switching circuit 13 that switches between the output of the observer and the output of the LPF according to whether the observer is on or off. When the observer processing is off, the output of the LPF is supplied to the summing circuit. COPYRIGHT: (C)2006,JPO&NCIPI
|
