Servo device for spindle motor
First Claim
1. A servo device for servo controlling a spindle motor, comprising:
- means for generating a signal with at least two cycles during one full rotation of a rotator in said spindle motor in accordance with a rotational movement of said rotator;
means for measuring a period for at least one cycle in one full rotation of said rotator;
means for storing at least one target period corresponding to said measured period for said at least one cycle in one rotation of said rotator;
means for comparing said respective measured period with said corresponding target period stored in said storing means; and
speed controlling-means for controlling a rotational speed of said rotator in response to a result of said comparing means.
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Accused Products
Abstract
A servo device for servo controlling a spindle motor according to the invention, comprising: a unit for generating a signal with at least two cycles during one full rotation of a rotator in the spindle motor in accordance with a rotational movement of the rotator; a unit for measuring a time required for each of the two periods; a unit for storing at least two target time corresponding to the two periods respectively; and a speed controlling unit for controlling a rotational speed of the rotator at the basis of the comparison between the respective measured period and the corresponding target period. Therefore, a current error of the measurement of periods are associated with the time of half the period preceding the current period, thereby the detection with the reduced delay can be performed in comparison with the detection at the time of one half rotation.
21 Citations
16 Claims
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1. A servo device for servo controlling a spindle motor, comprising:
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means for generating a signal with at least two cycles during one full rotation of a rotator in said spindle motor in accordance with a rotational movement of said rotator; means for measuring a period for at least one cycle in one full rotation of said rotator; means for storing at least one target period corresponding to said measured period for said at least one cycle in one rotation of said rotator; means for comparing said respective measured period with said corresponding target period stored in said storing means; and speed controlling-means for controlling a rotational speed of said rotator in response to a result of said comparing means. - View Dependent Claims (2, 5, 6)
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3. A servo device for servo controlling a spindle motor, comprising:
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means for generating a signal with at least two cycles during one full rotation of a rotator in said spindle motor in accordance with a rotational movement of said rotator; means for measuring a period for each of said cycles in one full rotation of said rotator; means for computing a period for one full rotation of said rotator from said plural measured periods for each of said cycle; means for storing a target period corresponding to each of said measured periods for said cycle in one rotation of said rotator; comparing means for comparing said computed period for one full rotation of said rotator with a target period required for one full rotation of said rotator computed from said periods; judging means for judging from a result of said comparing means whether said rotational speed of said rotator is one state or another state, said one state being that said rotational speed is out of a predetermined range and said another state being that said rotational speed is in said predetermined range; and speed controlling means for controlling said rotational speed of said rotator in response to a result of said comparing means. - View Dependent Claims (4, 15)
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7. A servo device for servo controlling a spindle motor, comprising:
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means for generating a signal with at least two cycles during one full rotation of a rotator in said spindle motor in accordance with a rotational movement of said rotator; means for measuring a period for each of said cycles; means for storing at least two target periods corresponding to the measured period, or measured periods respectively; means for computing a period required for one full rotation of said rotator from the plural measured periods; first judging means for judging whether the rotational speed of said rotator computed from the computed time required for one full rotation of said rotator is in the predetermined range or not; means for computing a rotational angular acceleration from the computed time required for one full rotation; second judging means for judging whether a rotational state of said rotator is stable or not from the computed rotational angular acceleration; and speed controlling means for controlling a rotational speed of said rotator at the basis of the plural measured periods and said target periods. - View Dependent Claims (8, 9, 10, 12)
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11. A servo device for servo controlling a spindle motor, comprising:
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means for generating a signal with at least two cycles during one full rotation of a rotator in said spindle motor in accordance with a rotational movement of said rotator; means for measuring a period for each of said cycles; means for storing at least two target periods corresponding to the measured periods, or measured periods respectively; means for computing a rotational angular acceleration from the plural measured periods; judging means for judging whether a rotational speed of said rotator computed from the rotational angular acceleration is in a predetermined range or not; and speed controlling means for controlling a rotational speed of said rotator in response to a result of said judging means. - View Dependent Claims (13, 14, 16)
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Specification