US 2007/0183076 A1 · DISK DRIVE USING A DISTURBANCE SENSOR FOR DISTURBANCE FREQUENCY-IDENTIFICATION AND SUPPRESSION

Abstract

A magnetic recording disk drive has a disturbance sensor and a disturbance frequency identifier that are used to adjust the frequency of a peak filter as the disturbance frequency changes. The sensor and the frequency identifier are separate from the servo control loop and thus do not rely on the head position error signal (PES) to predict the disturbance frequency. The adjustable peak filter is coupled in parallel with the servo feedback controller. The peak filter modifies the open loop transfer function and the error rejection function of the servo control loop to provide a higher rejection at the identified frequency. The peak filter may be switched out of or uncoupled from the servo feedback controller during track-seeking or as desired, depending on the amplitude of the sensor signal or the amplitude of the PES.

Claims10

Dependent claims

A disk drive comprising:

a rotatable disk having a plurality of tracks containing positioning information;
a head movable across the disk, the head being capable of reading positioning information in the tracks;
an actuator for moving the head;
a sensor for sensing a disturbance to the disk drive;
a feedback controller providing a controller output as an actuator input to drive the actuator;
a feedback loop to feed a head position at an output of the actuator as an input back to the controller to produce a position error signal (PES);
an adjustable peak filter coupled to the feedback controller;
and
a frequency identifier coupled to the sensor for identifying the frequency of a disturbance detected by the sensor, the frequency identifier output being input to the adjustable peak filter to select the frequency of the peak filter;
whereby the influence of the disturbance on the actuator at the identified frequency is substantially suppressed.

7 more elements

A processor-implemented method for operating a disk drive, the disk drive including (a) a rotatable magnetic recording disk having a plurality of concentric data tracks containing servo positioning information;

(b) a recording head movable across the disk, the head being capable of reading data and servo positioning information in the data tracks;
(c) an actuator for moving the head;
(d) a sensor for sensing a disturbance to the disk drive;
(e) a processor for receiving a position error signal (PES) from the servo positioning information and a signal from the sensor and for generating a actuator control signal to the actuator;
and (f) memory coupled to the processor and containing a program of instructions readable by the processor, the program including an actuator feedback controller, a frequency identifier, and a peak filter;
the processor-implemented method comprising:
calculating, from the PES and the actuator feedback controller, the actuator control signal in the absence of a disturbance to the disk drive;
calculating, from the sensor signal and the frequency identifier, the frequency of a disturbance to the disk drive;
selecting said calculated frequency as the peak frequency of said peak filter;
and
calculating, from the PES, the actuator feedback controller, and the peak filter, the actuator control signal in the presence of a disturbance to the disk drive at said frequency.

8 more elements

Dependencies are inferred from the claim text.

Disk drive using a disturbance sensor for disturbance frequency-identification and suppression

Life of this patent

Disk drive using a disturbance sensor for disturbance frequency-identification and suppression

Life of this patent

Abstract

Claims10