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US 2009/0154313 A1Published application
Optical Disc Apparatus
AssigneesHitachi, Ltd., Hitachi-LG Data Storage, Inc.
InventorShinsuke ONOE
Life of this patent
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Abstract
In servo control within an optical disc apparatus, when iterative learning control is started, the servo characteristics are modified to servo characteristic giving increased gains during a given period of time. Under this condition, the iterative learning control is provided.
Claims10
An optical disc apparatus for recording or reading information to or from an optical disc by irradiating the disc with laser light, said optical disc apparatus comprising:
- an optical detection module to produce an electrical output signal corresponding to the amount of light reflected from the optical disc;
- a servo error signal creation module to create a servo error signal from the output signal from the optical detection module;
- a feedback control module to create a drive signal for driving a servo actuator based on the servo error signal and to provide feedback control;
- a disc rotation module to rotate the optical disc;
- an addition module to add a compensation signal to a given signal within a servo loop, said compensating signal acting to compensate for periodical external disturbances entered to a servo system of the optical disc apparatus;
- a storage module to store an output signal from the addition module for an interval of time corresponding to at least one rotation of the optical disc;
- and
- an iterative learning control module to provide control of iterative learning control;
- wherein said iterative learning control module modifies filter characteristics set to said feedback control module to given filter characteristics providing increased gains;
- wherein outputting of the iterative learning control is started after a lapse of the period of at least one rotation after the modification of the filter characteristics;
- and
- wherein the filter characteristics set to said feedback control module are modified to steady-state servo characteristics after a lapse of a given time since the start of the outputting of the iterative learning control.
9 more elements
An optical disc apparatus for recording or reading information to or from an optical disc by irradiating the disc with laser light, said optical disc apparatus comprising:
- an optical detection module to produce an electrical output signal corresponding to the amount of light reflected from the optical disc;
- a servo error signal creation module to create a servo error signal from the output signal from the optical detection module;
- a feedback control module to create a drive signal for driving a servo actuator based on the servo error signal and to provide feedback control;
- a disc rotation module to rotate the optical disc;
- an addition module to add a compensation signal to a given signal within a servo loop, said compensation signal acting to compensate for periodical external disturbances entered to a servo system of the optical disc apparatus;
- a storage module to store an output signal from the addition module for an interval of time corresponding to at least one rotation of the optical disc;
- and
- an iterative learning control module to provide control of iterative learning control;
- wherein said iterative learning control module modifies filter characteristics set to said feedback control module to given filter characteristics providing increased gains;
- wherein outputting of the iterative learning control is started after a lapse of the period of at least one rotation after the modification of the filter characteristics;
- and
- wherein the filter characteristics set to said feedback control module are modified to one filter characteristic or plural filter characteristics in turn with the lapse of time after the start of the outputting of the iterative learning control and then to the steady-state servo characteristics.
9 more elements
An optical disc apparatus for recording or reading information to or from an optical disc by irradiating the disc with laser light, said optical disc apparatus comprising:
- an optical detection module to detect the amount of light reflected from the optical disc;
- a servo error signal creation module to create a servo error signal from an output signal from the optical detection module;
- a feedback control module to create a drive signal for driving a servo actuator based on the servo error signal and to provide feedback control;
- a disc rotation module to rotate the optical disc;
- an addition module to add a compensation signal to a given signal within a servo loop, said compensating signal acting to compensate for external disturbances entered to a servo system of the optical disc apparatus;
- a storage module to store an output signal from the addition module for an interval of time corresponding to at least one rotation of the optical disc;
- and
- an iterative learning control module to provide control of iterative learning control;
- wherein said iterative learning control module modifies filter characteristics set to said feedback control module to given filter characteristics providing increased gains;
- and
- wherein the filter characteristics set to the feedback control module is modified to steady-state servo characteristics after a given time and the iterative learning control is outputted.
8 more elements
Dependencies are inferred from the claim text.