Position control method, position control device, and medium storage device having disturbance suppression function
First Claim
1. A position control method for controlling a position of an object to a predetermined position by an actuator, comprising:
- a step of computing a position error based on a target position of the object and a current position of the object;
a step of computing a control value in which a disturbance frequency component is suppressed, using a predetermined feedback loop based on the position error and computing a drive value of the actuator by multiplying the control value by a loop gain;
a step of fetching a target loop gain according to the disturbance frequency from a table;
a step of adding disturbance of a measurement frequency to the feedback loop and measuring a loop gain of the feedback loop; and
a step of calibrating the loop gain of the control value computing step based on the measured loop gain and the target loop gain.
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Accused Products
Abstract
In a position control device having a disturbance suppression function, loop gain is calibrated without stopping disturbance suppression control. The position control device has, for disturbance suppression control, a feedback controller for changing the loop characteristic, a table for storing a target gain according to a disturbance frequency, and a gain calibration section for calibrating open loop gain. The gain is calibrated using a target gain in the table according to the change of the loop characteristic of the feedback controller. Open loop gain can be calibrated without interrupting the disturbance suppression control, so the open loop gain can be accurately calibrated without being affected by disturbance, and accurate position control is possible.
49 Citations
21 Claims
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1. A position control method for controlling a position of an object to a predetermined position by an actuator, comprising:
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a step of computing a position error based on a target position of the object and a current position of the object; a step of computing a control value in which a disturbance frequency component is suppressed, using a predetermined feedback loop based on the position error and computing a drive value of the actuator by multiplying the control value by a loop gain; a step of fetching a target loop gain according to the disturbance frequency from a table; a step of adding disturbance of a measurement frequency to the feedback loop and measuring a loop gain of the feedback loop; and a step of calibrating the loop gain of the control value computing step based on the measured loop gain and the target loop gain. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A position control device for controlling a position of an object to a predetermined position by an actuator, comprising:
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a control unit for computing a position error based on a target position of the object and a current position of the object, computing a control value in which a disturbance frequency component is suppressed, using a predetermined feedback loop based on the position error, and multiplying the result by a loop gain, so as to compute a drive value of the actuator; and a table for storing a target loop gain according to the disturbance frequency, wherein the control unit fetches the target loop gain according to the disturbance frequency from the table, adds a disturbance of a measurement frequency to the feedback loop, measures a loop gain of the feedback loop, and calibrates the loop gain in the control value computing step based on the measured loop gain and the target loop gain. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A medium storage device, comprising:
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a head for at least reading data on a storage medium; an actuator for positioning the head to a predetermined position on the storage medium; a control section for computing a position error based on a target position of the head and a current position acquired from the head, computing a control value in which a disturbance frequency component is suppressed, using a predetermined feedback loop based on the position error, and multiplying the result by a loop gain, so as to compute a drive value of the actuator; and a table for storing a target loop gain according to the disturbance frequency, wherein the control section fetches the target loop gain according to the disturbance frequency from the table, adds a disturbance of a measurement frequency to the feedback loop, measures loop gain of the feedback loop, and calibrates the loop gain in the control value computing step based on the measured loop gain and the target loop gain. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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Specification