JPH0828078B2 - Direct access storage device and operating method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct access storage device (DASD), and more particularly to a device such as a magnetic disk device having position control of an actuator by a servo system.

[0002]

2. Description of the Prior Art Typical DASD actuator / head devices have several significant structural resonance modes, which are slowly damped and degrade servo system performance. It will be. These modes are activated during the track-access and track following phases of servo-controlled actuator operation. The open loop unity gain of the servo system, and these modes having a frequency close to the crossover frequency significantly reduce the phase margin of the servo system, leading to an unstable state and serious deterioration of the settleout performance. Furthermore, these modes are subject to changes in amplitude and frequency due to environmental conditions such as temperature and changes over time and wear. Other causes of such changes are manufacturing tolerances for each device in a multi-disk DASD and suspension non-uniformity for each head. In particular, it has been observed that the modal frequency varies significantly with low end plastic actuators. If this is not corrected, these modes will lead to excessive settling out and increase TMR error.

In today's techniques for mode correction, notch filters suppress the dominant structural modes.
Conventional designs require relatively wide band and fixed frequency rejection to compensate for changes in these modes. However, a major limitation of these designs is the introduction of phase delay, which reduces phase margin and seriously degrades servo system performance.

It is an object of the present invention to provide a direct access storage device that has a short settling time.

Another object of the present invention is to provide a direct access storage device that automatically compensates for changes in the resonance characteristics of the actuator as a function of time.

Another object of the present invention is to provide a direct access storage device that mitigates manufacturing tolerances of components within the actuator assembly.

A further object of the present invention is to provide a low cost direct access storage device which achieves the above objects.

[0008]

According to the present invention, a servo system for controlling the position of a head that interacts with a recording medium is provided.
Direct access storage devices, including loops, have actuator means for moving the head. The drive circuit supplies energy to this actuator means. The control device controls the drive circuit. Periodically at least one resonant frequency of the actuator (generally the most annoying)
Means are provided for determining Filtering means are located in the servo loop to minimize the system response for at least one selected frequency. Also,
Means are provided for configuring the filter means to filter at least one resonant frequency determined by the determining means described above.

The means for determining at least one resonant frequency of the actuator means comprises means for injecting a signal into the servo loop and means for monitoring the response of the actuator means to determine at least one resonant frequency. . The determining means preferably includes means for varying the frequency of the signal over a frequency range that includes the at least one resonant frequency of the actuator means.

The determining means includes a programmed microprocessor which is a component of the controller.

The filter means is a switched capacitive filter having a center frequency, the bandwidth of which is controlled by a clock signal provided by a phase lock loop (or program timer). The frequency of the phase lock loop is controlled by the microprocessor.

The means for determining at least one resonant frequency of the actuator means, the filter means, and the filter construction means are all implemented by a microprocessor under software control. The microprocessor may be a microprocessor included in the control device.

According to the present invention, there is also provided a method for operating a direct access storage device having a servo system for controlling the position of an actuator of a head that interacts with a recording medium. The method comprises the steps of periodically determining at least one resonant frequency of the actuator means, and configuring filter means in the servo system to minimize the response of the actuator to said at least one resonant frequency. .

Prior to determining at least one resonant frequency, it is desirable that the notch frequency be shifted outside the frequency range of interest. Alternatively, the filter may be disabled and reused after it is configured.

The step of periodically determining at least one resonant frequency comprises injecting a signal into the servo loop and monitoring the response of the actuator means. The frequency of the injected signal is preferably variable over a frequency range that includes at least one resonant frequency of the actuator means.

According to the invention, this signal is preferably a digitized sine wave, which is injected at the input of the D / A converter, which in turn controls the digital output of the microprocessor. Convert to an analog signal for supply to the drive circuit. This reduces the computational load on the microprocessor.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Although the present invention will be described with reference to a magnetic disk drive, those skilled in the related arts will find that the present invention is
It will be appreciated that it is applicable to any direct access storage device that includes a servo position control system having a mechanical resonant mode, such as a device using an optical storage medium.

FIG. 1 shows a part of a disk drive unit and components related to a sector servo position control system used therein. A magnetic disk 10 having a number of circumferential tracks 12 is a motor (not shown) as is already known.
Is rotated by. The read / write head 14 is located in close proximity to the surface of the disk 10 and digital information is stored on and read from the track 12. The disk 10 is divided into sectors 16 and, as is known, each track has, for each sector, an area 18 used to store information identifying a particular track and sector. As is known, the detection of this information by the read / write head 14 and subsequent processing by the read / write circuit 20 and decoder 22 produces a position error signal (PES) on line 24. Decoder 22 also produces a data stream on line 26 for use by the processor associated with the direct access storage device.

As is known, read / write head 14 is mounted on suspension 28. The suspension 28 is attached to an arm 29, which rotates about a shaft 30 by the action of a VCM (voice coil motor) 32 located in a magnetic field (not shown). The current for driving the VCM 32 is supplied from the drive circuit 34.

And as is also known, line 24
The above analog position error signal is supplied to the controller 35,
The digital signal is converted by the A / D converter 36. The output of the converter 36 is subtracted by the digital adder 38 from the track reference signal generated by the track reference signal generator 39. The output of the adder 38 is the microprocessor 4
4 inputs. The output of the track reference signal generator 39 is also provided on line 45 to the microprocessor 44, the reason for which will be described later.

The microprocessor 44 performs appropriate calculation and supplies the result to the D / A converter 46. The output of the D / A converter 46 is given to the notch filter 48 via a summing combiner 49. As described above, in the conventional device, the notch filter is generally composed of a wide band frequency filter, and suppresses the resonance mode of the actuator (including the suspension 28) of the head 14. As will be appreciated by those skilled in the relevant arts, the dominant resonant frequency of the actuator is influenced by the design of all head positioning components responsible for operation such as head 14, suspension 28 and VCM 32. However, the suspension 28, although part of this system, is most associated with changes in resonant frequency with time and temperature, which changes cause excessive ringing in the control position.

In prior art devices, the output of notch filter 48 is typically provided directly to the input of drive circuit 34. However, in accordance with the present invention, the notch filter is bypassed depending on the position of the two pole switch 50 controlled by the signal provided on the line 52 from the microprocessor 44. Further, according to the present invention, the microprocessor 44 injects a sine wave into the summing coupler 49 by controlling the oscillation frequency of the sine wave generator 54, and outputs the outputs of the D / A converter 46 and the sine wave generator 54. Is added.

The sine wave generator 54 is a microprocessor 44.
Although illustrated as a separate oscillator having a frequency determined by the control output from, the signal may be generated digitally by microprocessor 44. In this case, the sine wave generator 54 may simply be a low pass filter that transforms the pulse provided by the microprocessor 44 into an approximation of the sine wave provided to the summing combiner 56.

In accordance with the present invention, the notch filter 48
Are programmable in response to inputs received from the microprocessor 4 via bus or line 57.
Thus, the servo system shown in FIG. 1 operates in two modes. The first mode is the resonant frequency determination mode, in which switch 50 is placed in the position shown in FIG. Removed from. The frequency of the sine wave generator 54 is changed by the microprocessor 44 over time. The response of this system to the signal injected into summing combiner 49 is monitored by microprocessor 44 while head 14 is controlled to follow any track on disk 10. Monitoring is accomplished by examining the PES amplitude for each frequency. For example, the absolute value of the PES amplitude for n samples is added and the sum of the results of the addition is divided by n to determine the average value of PES for a particular frequency. This frequency is then changed and the same calculation is achieved by the microprocessor 44.

As will be appreciated by those familiar with this technique, other types of calculations are achievable. For example, the RMS value of the position error signal may be calculated. Alternatively,
If realistic, different waveforms could be injected and a Fast Fourier Transform analysis could be achieved. However, stable sinusoidal injection and observation of PES occurring in closed-loop track-following mode have been performed by a simple and low-cost microprocessor to characterize the amplitude versus frequency response of the dominant resonant mode of the actuator device. . However, this is limited to cases where the frequency range of the sine wave generator 54 controlled by the microprocessor 44 is sufficiently inclusive of those frequencies of interest.

As will be appreciated by those familiar with this technique, the determination of the resonant frequency in the above modes can be determined by the DAS.
This is performed when D is not in the idle state. Ie DASD
The data used by the host processor involved in is not written to or read from the disk 10.

Upon completion of this first mode of operation, the microprocessor transitions to the second mode.
Here, the notch filter 48 is the microprocessor 44.
Programmed to suppress at least one dominant resonant mode of the actuator device. Appropriate outputs from microprocessor 44 are provided on line 57. When notch filter 48 is programmed, microprocessor 44 causes line 5 to provide the output (not the input) of notch filter 48 to drive circuit 34.
Control switch 50 via 2 (not shown in FIG. 1). At this time, DASD is conventionally used for storage and / or retrieval of information from disk 10.

The response of the system is thus optimized so that when changes in the resonant frequencies of the dominant modes occur, notch filter 48 is automatically reprogrammed to suppress these modes.

A simple approach to effectively disabling and re-enabling notch filter 48 is to simply reprogram it so that the notch frequency is outside the frequency range of interest. However, the notch must not have a frequency that renders the servo system unusable.
If the notch is moved to a higher frequency than the frequency range of interest, the servo system will still function and will have essentially the same response as the notch filter 48 was removed from the servo loop by switch 50. Let's respond in form. This makes programming of the switch 50 and the microprocessor 44 controlling the switch 50 unnecessary. As a general recognition, the prohibition of use of the notch filter 48 simply means that when the resonance of the suspension 28 occurs in a frequency range higher than the applicable frequency range, the notch filter 48 does not operate in the applicable frequency range.
It means that the filter 48 effectively acts so as not to cause attenuation.

The exact resonant frequency of vibration of the actuator device may change with load. Therefore, this resonant frequency may change with the radial position of the head 14 depending on the change in applied control force or the radial change with respect to the deviation of the rotating disk 10.
The frequency of the dominant resonant mode may be determined with various radial positions of the head 14 to further improve settling out performance. For example, the frequency of the sine wave generator 54 may be varied over the range of interest while the head 14 is controlled to the innermost track, the outermost track, and the middle track of the disk 10. The data regarding the resonance frequency of the actuator device is then stored in the RA connected to the microprocessor 44 by the bus 59.
It is stored in M58 (for illustration, RAM 58 is shown external to microprocessor 44, but may be incorporated into the microprocessor).

When the host processor accesses a particular track, the track reference signal generator 39 is instructed to provide the appropriate inputs to both the adder 38 and the microprocessor 44 (line 45 for the latter). provide). Microprocessor 44 then accesses the information stored in RAM 58 and configures notch filter 48 appropriately. Information about the closest track whose resonant frequency has been determined is used to construct the notch filter 48. However, it is more desirable for microprocessor 44 to achieve interpolation between data from both sides of the track being accessed (under the control of appropriate programming). This allows the notch filter 48
Is most accurately tuned to the precise resonant frequency or frequencies associated with the accessed track of the actuator device.

The embodiment of the invention shown in FIG. 1 is suitable for a low end magnetic disk drive associated with a typical personal computer or laptop computer. In this type of direct access storage device, the servo system PES sampling rate is low. For example, 1.
It is 8 kHz. The dominant resonant mode frequency of vibration of the head positioning actuator will be N times this frequency or more. Here, N is a small integer. The actual resonant frequency is identified by monitoring the false signal frequency and using the false signal mode information. Thus, PE
It is known that even if S is sampled at 1.8 kHz, higher frequencies are injected, and the increase in amplitude of PES at lower sampling rates is associated with an increase in the oscillation amplitude of the injection frequency.

FIG. 2 shows a block diagram of programmable notch filter 48 and its connection to microprocessor 44. The programmable notch filter 48 is
For example, National Semiconductor's integrated circuit MF
Switched capacitive filters achieved using 10 are desirable. The filter 48 has two main components: a clock frequency generator 60 and a gain-bandwidth section 62. The timer 64 in the microprocessor 44 has a frequency fn.
Produces a square wave input, which is provided as an input to the clock generator 60. The clock generator 60 includes a phase comparator 66, a low pass filter 68, an amplifier 70, a voltage controlled oscillator 72, and two frequency dividers 76A and 76B.
One output connected to the other input 10
It is preferably a phase-locked loop including a divide-by-zero divider circuit 74.

The phase lock loop thus acts as a frequency multiplier and the voltage controlled oscillator 72 produces an output frequency f _clk which is 100 times the input frequency provided by the timer 64 of the microprocessor 44. This clock is provided to the input of the gain-bandwidth section 62 of the programmable notch filter.

The gain-bandwidth section 62 includes an input amplifier 78, a switch 80, a summing multiplier 81, and two cascaded amplifiers 82 and 84. The bandwidth and gain of this filter is controlled by the resistance values of resistors 86, 88 and 90. The center frequency of the filter is determined by the clock frequency f _clk supplied to the switch 80. f _clk is f
is a 100 times _n, the center frequency of the filter is equal to f _n.

The component values for the notch filter 48 will be selected according to the criteria set forth in the manufacturer's application design data sheet. Using these criteria for the device described above, the deviation of the center frequency from the target frequency is on the order of 0.2% and the attenuation is on the order of 32 dB. In addition, the bandwidth of the notch filter 48 is also programmable by switching to different resistors under the control of the microprocessor 44, and the programming is modified as needed to compensate for changes in the dominant resonant frequency of the actuator device. can do. Generally, a bandwidth of about 30 Hz is desirable, but if the two resonant frequencies are separated by 50 Hz, for example, the bandwidth will be extended to a value such as 60 Hz and both modes will be suppressed. This is achieved without reducing the phase margin because the required bandwidth is still narrow. Alternatively, according to the invention, if the resonant modes are separated by a relatively large frequency difference in the actuator design, more than one filter stage or several filters are used. In this case, multiple reprogrammable narrowband filters maintain phase margin during tracking frequency changes, thereby achieving performance that exceeds the settling performance provided by a single wideband filter.

It will be appreciated that in this way several filters are cascaded. By using one National Semiconductor integrated circuit MF10,
Two second order filters or one fourth order filter are provided.

Another approach to programming the notch filter is to use a programmable timer controlled by the microprocessor 44. In this case, the programmable timer produces a clock frequency input for the gain-bandwidth portion of the notch filter, eliminating the need for a phase lock loop. Such a programmable timer is implemented by driving a frequency divider circuit using a high frequency clock, as is already known.

The embodiment of the invention described in FIGS. 1 and 2 is most useful in low end disk drives of the type used in personal and laptop computers. The present invention also utilizes software elements rather than hardware elements,
It will also be implemented in high-end multi-disc high-performance disc devices.

FIG. 3 is a high-end DA using the present invention.
7 is a representation of SD, in which most of the functionality achieved in the hardware of FIG.
Achieved by software. Regarding the reference numbers in FIG. 3, the same numbers are assigned to the elements having the same functions as those described in FIG. However, there are exceptions to the points described below.

As mentioned above, high-end DASD
In the prior art, the use of a narrow band digital notch filter to suppress the dominant resonance mode of the suspension has been a conventional example.

In general, due to the high sampling rate, these narrow band digital notch filters are
It is implemented by software or a firmware program that controls the operation of microprocessor 44 of controller 35. However, as mentioned above,
The fixed programming associated with these notches does not allow the center frequency to be readjusted to accommodate changes in the resonant frequency due to component temperature or aging.

According to the invention, the programmed software notch is disabled. The microprocessor then produces a digital sine wave, which is injected into the servo loop. During this period, the filter is in the use prohibited state. This sine wave is generated directly by the microprocessor by utilizing a look-up table with sine values. To change this frequency, it is only necessary to change the clock frequency while accessing subsequent values in the look-up table.

In this way, the microprocessor 44 generates a sine wave, sweeps its frequency, and internally performs all necessary calculations. However, it is also possible to provide a digital sine wave on the bus or line 94 as the output of the microprocessor. This output is the D / A converter 46.
Given as input. The advantage of this configuration is that it takes advantage of the high speed of the D / A converter 46, freeing the microprocessor 44 from additional computational load. However, if the computational load of the microprocessor 44 is light, the microprocessor 44 can be used to control the analog signal generator. This generator is merely a filter arrangement for converting the digital sine wave provided by the microprocessor 44 into an analog signal, as already described for the generator 54 of FIG. This analog signal is injected into the summing coupler 96 existing between the D / A converter 46 and the driving circuit 34.

In both cases, the system response reflected in the PES amplitude is monitored as the frequency of this injected signal changes. This range of change includes the dominant resonance mode of the head positioning actuator including the suspension 28. Once the positions of these resonant modes have been determined,
The software notch filter is reprogrammed so that the narrow band notch contains one of at least three frequencies. After the notch is reprogrammed, the notch is re-enabled and the system is in use.

The above steps for reprogramming the notch filter are accomplished at boot up of the system and when the DASD is idle. The former accommodates long-term changes in components, while the latter accommodates short-term changes induced by, for example, short-term changes in operating temperature while the system is in use.

The main advantages of DASD utilizing the present invention are:
The manufacturing tolerances of the mechanical components associated with the positioning actuator device can be somewhat relaxed. Since the device is tuned or programmed automatically, the exact frequency of the dominant resonant frequency mode is not important. In addition, real-time information from the most recently determined frequencies for these resonant modes is used to periodically reprogram the device so that these frequencies are kept strictly constant or they are manufactured. There is no need to overdesign the components in order to ensure that they do not change due to different drives in the process.

The additional costs associated with the present invention are offset by the manufacturing savings, while at the same time providing improved performance with respect to settling time. In any case, the additional cost is small.
In high end devices, only reprogramming of the microprocessor in the controller is required. In low end devices, the additional hardware components do not add significant cost to the device.

FIG. 4A is a graph showing the position error signal as a function of time in the track following mode when the notch filter is not used. FIG. 4B represents the corresponding change in the control voltage to the drive circuit. Here, it is clear that the changes in PES and control voltage are quite large, and the settling time is long.

FIG. 5A is a graph of the response of the position error signal as a function of time with the narrow band notch filter enabled under the same conditions and in the same apparatus as in FIG. 4A. FIG. 5B shows the corresponding change in the control voltage supplied to the drive circuit for the step input of FIG. 5A. The settle-out characteristics when using the narrow band notch filter are significantly improved compared to the case without it. This improvement in performance is achieved without sacrificing phase margin. This is because a narrow band filter was used, and according to the present invention, the same head-
It depends on being set exactly to the frequency corresponding to the dominant resonance mode or modes of the suspension system. This is achieved without the phase loop associated with the wide band notch filter.

FIG. 6 illustrates a multi-platter direct access storage device according to the present invention. A pair of disks 10A, 10
B is the spindle 1 of the disk / file drive motor 13
Supported on 1. Each of the disks 10A, 10B has two sides 15A, 15B and 17A, 17B. For the sake of explanation, the surface 15A on the disk 10 and the surfaces 17A and 17B on the disk 10B are data recording surfaces. The surface 15B on the disk 10A is a surface for servo and includes only pre-recorded servo information. Servo information is recorded in concentric tracks, typically servo surface 15
The intersection of adjacent servo tracks on B is surface 15A,
Radially aligned along the centerline of the data tracks on 17A and 17B. The servo information on surface 15B is a square pattern, as is well known.

Specific tracks on the data and servo disks are accessed by heads 14A, 14B, 14C and 14D, each head being associated with a respective disk surface and having a respective suspension 28A, 2A.
Supported by 8B, 28C and 28D. Head 14
A, 14B, 14C and 14D are connected to a common access means or actuator indicated by VCM 32, for example. Thus the heads 14A, 14B, 14C and 14D
All remain in fixed relation to each other with respect to their radial position on their respective disk surfaces.

The deviation loading on heads 14A and 14D is significantly different from the deviation loading on heads 14B and 14C. As a result, the dominant resonant frequency reflected in the position error signal varies considerably from head to head. Furthermore, there are also changes in the precise mechanical properties of the suspensions 28A-28D corresponding to each head 14A-14D, respectively, affecting the respective dominant mode frequencies of vibration. When a particular platter or disk is accessed, it is effective to construct a notch filter 48 to suppress the vibration frequency of the head used.

The surface 15B of the disk 10A is used as a surface for servo. Generally, the surfaces 15A and 17A are used.
And 17B also include servo sector information on at least their outermost tracks. Thus, according to the present invention, the dominant resonant modes of the suspensions of each of the heads 14A to 14D are all determined by moving these heads to the outermost track. The position error signal of each head is then monitored to determine the dominant resonant frequency of each head. This information is stored in the RAM 58. When data from a particular disk is accessed,
Microprocessor 44 provides track reference signal generator 3 with appropriate information about the disks and tracks to be accessed.
After receiving from 9, the notch filter 48 is constructed in the manner described above to suppress the frequencies in the dominant resonant mode of the head used. Thus, settling time in a multi-platter direct access memory is minimized without the use of wideband filters with severe phase delay.

This multi-disk device approach can be combined with the techniques described above to compensate for vibrations at track positions. Surfaces 15A, 17A, and 17B generally do not contain servo information (other than the outermost track), but by using the servo information on surface 15B, at least one resonant frequency is periodically used in various tracks. The determining step is accomplished.
This information for the various tracks is stored in RAM 58. A resonance frequency trend as a function of radial position is thus established for at least the head-suspension device of head 14B. These trends are used by the microprocessor 44 to be interpolated to provide correction to the remaining heads as a function of radius.

Alternatively, the servo sector information is displayed on each side 15A.
To 17D on multiple track positions, the resonant frequency of each head at each track position is determined periodically. At this time, the notch filter 48 is tuned precisely for the particular disc and the track is accessed. Corrections for head-suspension system changes, deviations, and other loading forces due to track position changes are all taken into account to achieve maximum system performance.

As a summary, Table 1 shows general guidelines for embodiments of the invention in high-end and low-end (sampling rate) DASD devices.

[0058] Table 1 High sampling rate low sampling rate resonant modes of directly identified sinusoidal observed pseudo signal sine wave observation resonant mode correction digital software tunable hardware notch Notch

While this invention has been described with reference to particular embodiments, those skilled in the relevant art will be able to modify and extend the disclosed embodiments without departing from the spirit of the invention. It will be understood.

[0060]

The effect of the change in the resonance frequency of the actuator can be reduced. For example, the settling time can always be shortened. It also reduces manufacturing tolerances on actuator components.

[Brief description of drawings]

FIG. 1 is a block diagram of a disk drive device according to the present invention.

FIG. 2 is a block diagram of the programmable notch filter of FIG.

FIG. 3 is a diagram showing another embodiment of the disk drive device according to the present invention.

FIG. 4A is a diagram illustrating the position error signal of a typical disk drive without proper filtering.

FIG. 4B is a diagram representing the control voltage of a typical disk drive without proper filtering.

FIG. 5A is a diagram showing a position error signal of the disk drive device according to the present invention.

FIG. 5B is a diagram showing a control voltage of the disk drive device according to the present invention.

FIG. 6 is a block diagram of a multi-disk type disk drive device according to the present invention.

[Explanation of symbols]

 10 disk 14 read / write head 20 read / write circuit 22 decoder 28 suspension 29 arm 32 VCM 34 drive circuit 35 controller 36 A / D converter 39 track reference signal generator 44 microprocessor 46 D / A converter 48 notch Filter 50 Switch 54 Sine wave generator

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuzo Nakagawa 26-48-504 Takamura, Hiratsuka-shi, Kanagawa Prefecture (72) Inventor Hal Chalmar Ottesen 4230, Rochester, North West, Stonham Rain, Minnesota, United States Address (72) Inventor Arun Sharma 51 Winding Brook Road, New Rochelle, New York, U.S.A. (72) Inventor Muttumbi Sri Jayantha 32 Sherwood Avenue, Osining, New York, USA (56) ) References JP-A-1-208776 (JP, A) JP-A-1-235082 (JP, A)

Claims (29)

[Claims] 1. A direct access storage device including a servo loop for positioning a head for interaction with a recording medium, the actuator means for moving the head, and energy for supplying the actuator means. A drive circuit, a controller for controlling the drive circuit, a means for injecting a signal into the servo loop, a frequency of the signal over a frequency range including at least one resonant frequency of the actuator means Means for monitoring the response of the actuator means when the frequency of the signal is changed to determine the at least one resonance frequency of the actuator means, and Arranged to minimize system response at at least one selected frequency Filter means for filtering said at least one selected frequency, and means for configuring said filter means to filter at least one resonant frequency determined by said determining means. And moving the head by the actuator means,
Means for causing a plurality of positions with respect to the storage medium, means for acquiring data indicating the at least one resonance frequency at each position, so that the control device can configure the filter means,
Means for providing the controller with data relating to at least one of the plurality of positions; and interpolation means used by the controller for interpolating data from at least two of the positions to generate interpolated data, A direct access storage device, wherein the control device configures the filter means according to the interpolation data. 2. The direct access storage device of claim 1, wherein the signal is a sine wave. 3. The direct access storage device according to claim 1, wherein said determining means includes a programmed microprocessor. 4. A direct access storage device according to claim 1, further comprising summing means arranged between the control device and the filter means, the injecting means injecting the signal into the summing means. . 5. The control device includes means for generating a position signal indicating the position of the head, and the control device is connected to the A / D converter for converting the position signal into a digital position signal. A microprocessor for processing the digital signal to generate a digital control signal; and a D / A converter connected to the microprocessor for converting the digital control signal into an analog control signal for positioning the head. And wherein the injected signal is digital and the injection means injects the signal at a point in the servo loop between the microprocessor and the D / A converter. 1. The direct access storage device according to 1. 6. The direct access storage device according to claim 1, further comprising means for prohibiting use of said filter means during operation of said determining means. 7. The direct access storage device according to claim 6, further comprising means for permitting reuse of the filter means after the filter means is configured by the configuring means. 8. The direct access storage device of claim 1, wherein said filter means comprises a switched capacitive filter. 9. The direct access storage device of claim 8 wherein said means for configuring includes clock signal generator means for providing a clock signal to said switched capacitive filter. 10. The direct access storage device of claim 9 wherein said clock signal generator means comprises a phase locked loop. 11. The direct access storage device of claim 10, wherein the phase lock loop is controlled by an input signal received from the controller. 12. The direct access storage device of claim 9 wherein said clock generator means includes a programmable timer programmed by said controller. 13. The direct access storage device of claim 1 wherein said filter means comprises a digital filter. 14. The direct access storage device of claim 13, wherein the digital filter is a software or firmware programmed filter. 15. The direct access storage device according to claim 1, wherein said filter means has a bandwidth of about 30 Hz. 16. The storage medium comprises a plurality of surfaces, the direct access storage device comprises a plurality of heads, each head interacting with a respective corresponding surface, and the actuator means comprises an actuator. The actuator is coupled to a plurality of suspensions, each suspension supporting one of the heads, means for obtaining from the heads data indicative of the at least one resonant frequency; So that the means can be configured,
3. The direct access storage device of claim 1, further comprising means for providing the controller with data from at least one of the heads. 17. A method of operating a direct access storage device including a servo system for controlling the position of actuator means of a head that interacts with a storage medium, comprising: a) injecting a signal into the servo system; Changing the frequency of the injection signal over a frequency range that includes at least one resonant frequency of the actuator means; and c) monitoring the response of the actuator means when the frequency of the injection signal is changed, the frequency range Determining at least one resonance frequency of the actuator means in the d), d) configuring a filter in the servo system to suppress the resonance frequency, and e) a plurality of storage media in the head. Locating, f) the actuation at each of the positions Obtaining data indicative of at least one resonance frequency of the data means; g) configuring the filter according to the data indicative of the at least one resonance frequency for one of the plurality of positions; and h) the above. An operation method comprising: interpolating data relating to at least two positions of a plurality of positions to generate interpolation data; and i) configuring the filter according to the interpolation data. 18. The step d) includes the steps a) to
18. The operating method according to claim 17, wherein the method is executed each time c) is executed. 19. The method of claim 17, further comprising the step of j) disabling the filter before performing step a). 20. The method according to claim 17, wherein k) the filter is enabled after performing step d).
The described operation method. 21. The method of claim 17, wherein the injection signal is a sine wave. 22. The operation of claim 17, wherein the injection signal is injected at a summing point between a drive circuit for the actuator means and a controller providing a control signal to the drive circuit. Method. 23. The servo system is a microprocessor, D /
An A converter, the signal is digital and the D /
18. A method according to claim 17, characterized in that it is injected into the input of an A converter and added with the control signal from the microprocessor. 24. The step of programming a microprocessor to perform at least one of steps e) and f).
The described operation method. 25. The method of claim 17, wherein the step of configuring the filter comprises the step of adjusting the clock frequency to a switched capacitive filter circuit. 26. The method of claim 17, wherein the step of configuring the filter comprises the step of programming one of a digital filter and a programmable timer. 27. A method as claimed in claim 17, comprising the step of constructing the filter having a bandwidth of about 30 Hz. 28. Configuring the filter according to data indicative of the at least one resonant frequency for one of the plurality of locations closest to a location on the storage medium to be accessed. The operating method according to claim 17. 29. The storage medium includes a plurality of surfaces, the direct access storage device includes a plurality of heads, each head interacting with a respective corresponding surface, and the actuator means includes a plurality of suspensions. A single actuator coupled to each suspension, each suspension supporting one of said heads, obtaining data from each head indicative of said at least one resonant frequency, said heads being used for access 18. The method of claim 17, comprising: configuring the filter according to data from one of the.