Positioning control system

A positioning control system comprising:

• a controlled device which has resonance characteristics, including resonance frequencies, and is positionable at a designated position;
• position detecting means for detecting a moved position of the controlled device;
• arithmetic control means for generating a drive signal based on a position detection signal from the position detecting means and based on said designated position;
• and
• drive means for moving the controlled device in accordance with said drive signal from said arithmetic control means,
• said arithmetic control means includes a low pass filter which has an abrupt slope and a discontinuous pole in the gain-frequency characteristics thereof, so that said resonance characteristics of said controlled device can be suppressed by means of said low pass filter, said arithmetic control means further comprising switch means for selectively turning said low pass filter off and on;
• wherein said switch means selectively turns said low pass filter off during a seek operation of said controlled device and on during a settling operation of said controlled device;
• wherein said low pass filter is constituted by a combination of a notch filter having said abrupt slope and an elliptical function filter having said pole, so that all the resonance frequencies occurring in said resonance characteristics can be suppressed;
• and
• wherein said low pass filter is constructed so as to be turned on and off, and an initial value to suppress the resonance characteristics by means of said low pass filter is given when said low pass filter is turned off.

A positioning control system for controlling a magnetic disk drive including:

• at least one magnetic disk which is rotated at a given speed by a spindle motor;
• at least one magnetic head which has resonance characteristics, including resonance frequencies, and is positionable at a designated position on said magnetic disk;
• and
• an actuator controlled to move said magnetic head, wherein said system comprises;
• position detecting means for detecting a moved position of said magnetic head;
• arithmetic control means for generating a drive signal based on a position detection signal from the position detecting means and based on said designated position;
• and
• drive means for moving said magnetic head in accordance with said drive signal from said arithmetic control means, wherein said arithmetic control means includes a low pass filter which has an abrupt slope and a discontinuous pole in the gain-frequency characteristics thereof, so that said resonance characteristics of said magnetic head can be suppressed by means of said low pass filter, said arithmetic control means further comprising switch means for selectively turning said low pass filter off and on
• wherein said switch means selectively turns said low pass filter off during a seek operation of said magnetic head and on during a settling operation of said magnetic head and wherein said low pass filter comprises a notch filter having said abrupt slope and an elliptical function filter having said pole, so that all the resonance frequencies occurring in said resonance characteristics can be suppressed.