US 6,958,882 B2 · Shock control for rotational recording apparatus

Abstract

A rotational recording apparatus that comprises a shock sensor and that adaptively processes the output of the shock sensor to obtain a feed forward signal, so as to implement a stable operation within a practical range. In a rotational recording apparatus wherein a VCM system having a transfer function (G) and a controller having a transfer function (H) perform feedback, the band of a signal(s) of a shock sensor (S) is limited by a bandpass filter (F), and a resultant signal (f) is employed to obtain the output of an adaptive filter (FIR). A signal (p) that a phase shift filter (P) outputs by shifting the phase of the signal f is employed as a signal to be transmitted to a parameter adaptation algorithm (PAA). Within the limited band, the phase of the phase shift filter P matches the phase of G/(1+GH) within a range of ±90 degrees.

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Drawings

Claims16

Dependent claims

A rotational recording apparatus comprising:

a head for reading data from a rotatable recording medium;
head driving means for driving said head;
head position detection means for outputting current data for a position of said head on said recording medium;
a controller for receiving a deviation between said current position data and a target position, and for generating a feedback control signal to be transmitted to said head driving means;
a sensor for detecting a disturbance that acts on said rotational recording apparatus;
a bandpass filter for passing an output signal of said sensor in a predetermined frequency band, wherein a pass band for said bandpass filter has a range between 200 Hz and 500 Hz;
an adaptive filter for receiving said output signal of said bandpass filter and for generating a feed forward control signal to be transmitted to said head driving means;
a phase shift filter for shifting a phase of said output signal of said bandpass filter;
and
adaptive algorithm means for calculating coefficients for said adaptive filter using said deviation and the signal output by said phase shift filter.

7 more elements

A method for controlling a rotational recording apparatus, which includes a head for reading data from a rotatable recording medium, head driving means for driving said head, head position detection means for outputting current position data for said head on said recording medium, a controller for receiving a deviation between said current position data and a target position and for generating a feedback control signal to be transmitted to said head driving means, and a sensor for detecting a disturbance that acts on said rotational recording apparatus, said method comprising the steps of:

sampling an output of said sensor and determining a sensor output s(n) that is discrete and quantized;
employing said sensor output s(n) to calculate output f(n) for a bandpass filter that has as a pass band a predetermined frequency band;
and
if |f(n)|/|s(n )|>0.8, then:
employing said output f(n) to calculate an output p(n) for a phase shift filter;
employing said output p(n) and an array P(n) composed of, as elements, values obtained at previous samplings for calculating coefficients R(n) for an adaptive filter;
employing said output f(n), an array F(n) composed of, as elements, values obtained at previous samplings, and said coefficients R(n) to calculate an output 1(n) for said adaptive filter;
and
adding said output 1(n) to said feedback control signal and transmitting the result to said head driving means.

6 more elements

Dependencies are inferred from the claim text.

Description6,065 words

Summary1,922 words

#This application claims the priority of Japanese Patent No. JP2001-290031 (IBM Docket No. JP920010157JP1), filed on Sep. 21, 2001, entitled “Shock Control For Rotational Recording Apparatus”.

#1. Technical Field

#The present invention relates to a rotational recording apparatus, such as a hard disk drive (hereinafter referred to as an HDD), and a control method therefor. More particularly, the present invention relates to a technique for applying feed forward control, using an adaptive filter, to control the position of an HDD head for which a shock sensor is provided.

Brief description of the drawings8 figures

#The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objects and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:

#FIG. 1 is a block diagram showing an example hard disk drive according to one embodiment of the present invention;

#FIG. 2 is a more detailed block diagram showing a hard disk controller 8 and its peripheral members;

Detailed description3,911 words

#The preferred embodiment of the present invention will now be described in detail while referring to the accompanying drawings. It should be noted, however, that the present invention can be implemented for various other modes and should not be limited to this embodiment. The same reference numerals are employed throughout the embodiment to denote corresponding or identical components.

#With reference now to FIG. 1 there is depicted a block diagram showing an exemplary hard disk drive according to one embodiment of the present invention. According to this embodiment, a hard disk drive 1 includes: a magnetic recording medium 2, a head 3, a voice coil motor (VCM) 4, an arm 5, a head preamplifier 6, a servo channel 7, a hard disk controller 8, a VCM driver 9, a shock sensor 10, a bus 11, a RAM (Random Access Memory) 12, a ROM (Read Only Memory) 13 and an interface 14.

#The magnetic recording medium 2 is a recording disk medium, rotated by a spindle motor, for example, on which information is magnetically recorded, and on which position data is radially recorded in advance.

Facts

Application

10/245,258Filed 17 Sep 2002

Priority

JP 2001-29003121 Sep 2001

Published

US 2003/0058571 A127 Mar 2003

Granted

25 Oct 2005

Term ended

22 Jul 2023

Estimated · how

20 years from earliest known nonprovisional domestic filing plus recorded patent term adjustment, including 308 days of adjustment. Maintenance-fee lapses, terminal disclaimers and statutory extensions have not been checked. The continuity chain may be incomplete; this is not an enforceability determination.

Classification2 codes

G11B 5/5582
Across disk tracks: system adaptation for working during or after external perturbation, e.g. in the presence of a mechanical oscillation caused…
G11B
Information storage based on relative movement between record carrier and transducer

Timeline

21 Sep 2001Priority claimedJP 2001-290031
17 Sep 2002Application filedUS 10/245,258
17 Sep 2002Assigned to International Business Machines Corporationassignment of assignor's interest
27 Mar 2003PublishedUS 2003/0058571 A1
4 May 2005Assigned to Hitachi Global Storage Technologies Netherlands B.V.assignment of assignor's interest
25 Oct 2005GrantedUS 6,958,882 B2
25 Oct 2012Assigned to Hgst Netherlands B.V.change of name
5 Dec 2016Assigned to Western Digital Technologies, Inc.assignment of assignor's interest
22 Jul 2023Term endedEstimated, includes 308 days of adjustment

Shock control for rotational recording apparatus

Life of this patent

Shock control for rotational recording apparatus

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims16

Description6,065 words

Drawings

Classification2 codes

Life of this patent

Description6,065 words