Position control method, position control device, and medium storage device having disturbance suppression function

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.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2006-246451, filed on Sep. 12, 2006, the entire contents of which are incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to a position control method, position control device and medium storage device for controlling the position of an object by suppressing disturbance, and more particularly to a position control method, position control device, and medium storage device for suppressing the position deviation of an object due to disturbance.[0004]2. Description of the Related Art[0005]A position control device is for controlling the position of an object to a specified position and is widely used in various fields. For example, in a medium storage device, such as a magnetic disk device and an optical disk device, it is extremely critical to accurately p...

AI Technical Summary

Benefits of technology

[0013]With the foregoing in view, it is an object of the present invention to provide a position control method, position control device, and medium storage device for accurately calibrating the open loop gain in a position control system using the disturbance adaptive control.

[0014]It is another object of the present invention to provide a position control method, position control device, and medium storage device for accurately calibrating the open loop gain even while disturbance is being applied.

[0015]It is still another object of the present invention to provide a position control method, position control device, and medium storage device for accurately calibrating the open loop gain, even if the disturbance suppression frequency is set from the outside.

[0016]It is still another object of the present invention to provide a position control method, position control device, and medium storage device for accurately calibrating the open loop gain, even if the position control system adapts to disturbance suppression frequencies in a wide range.

[0026]Because of disturbance suppression control, open loop gain is calibrated using a target gain according to a disturbance frequency, even if a loop characteristic of a feedback controller changes, so the open loop gain can be calibrated without interrupting the disturbance suppression control. Therefore the open loop gain can be accurately calibrated without being affected by disturbance, and accurate position control is possible.

Problems solved by technology

In this position control, it is known that disturbance affects positioning accuracy.

In this case, the external vibrations cannot be sufficiently suppressed and positioning accuracy drops since the adaptive control is stopped.

As a result, accuracy of gain adjustment drops.

In other words, in the case of such a position control system as an adaptive control system, disturbance is suppressed by changing the loop characteristic according to disturbance, so it is difficult to accurately calibrate the open loop gain of the control system using prior art.

Particularly if suppression width is taken wide or if disturbance in a high frequency area is suppressed to meet the recent demand for adapting a wide range of disturbance frequencies, the original characteristics of the controller are influenced, so it is more difficult to calibrate gain accurately.

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