Position controlling method

Abstract

The present invention provides a control system which reduces the sensitivity to acceleration disturbance like oscillation and improves the following-up capacity of following-up target position d- p while maintaining the stability thereof. A control system 201 is provided with a disturbance observer 6 which uses observable actuator control signal cont and zero following position x0 to obtain a disturbing force estimate value Di and a speed estimate value x0 ' which are respective estimate values of the disturbing force and the speed of a control object respectively. The disturbing force estimate value Di and the speed estimate value x0 ' are fed back, and thus the sensitivity to acceleration disturbance like oscillation is reduced and a position deviation d- p- e can be reduced while maintaining the stability of the system.

Description

technical field [0001] The present invention relates to tracking control. It is applicable to a control system that performs, for example, spot focus control or track control in an optical disc device. Background technique [0002] First, focus control or track control in a general optical disc device will be briefly described. The disc is stuck on the spindle motor, and the rotation of the spindle motor is controlled to make the disc rotate at a specified linear speed. [0003] In an optical disc device, in order to realize accurate recording and reproduction, it is necessary to focus and position a light spot from an optical pickup head on a recording track formed in a spiral shape on the optical disc surface with high precision. Because it is difficult to make the center hole of the disc exactly coincide with the rotation axis of the spindle motor, the rotation of the disc will produce an eccentricity of several hundred μm. In addition, due to the relationship between ...

AI Technical Summary

Problems solved by technology

[0047] The second prior art is effective when the amount of physical deformation of the disk is small, but there may be problems when the amount of physical deformation of the disk exceeds the standard limit of the disk.

[0064] According to the second prior art in this way, there is a second problem, that is, the residual deviation at the defect exit becomes large due to superimposed noise on the actuator control signal cont, and there is a risk of loss of control continuity.

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