JPH02312072A - Magnetic head positioning controller - Google Patents

Abstract

PURPOSE:To make follow-up characteristics invariably excellent by providing a target position calculating means, calculating a target data track position from the outputs of a position error detector and a motor position detector, and interpolating it. CONSTITUTION:The position error detector 4 generates a position error signal (e) at each sampling time from a signal reproduced by a magnetic head 1. Further, the motor position detector 5 detects a motor position and outputs a detected value (d). The signal (e) and detected value (d) are sent out to the target position calculating means 6 and a position error interpolating means 7 and the calculating means 6 generates the target position (r) at the sampling time. An interpolating means 7 generates a position error signal from the output (e) of the detector 4 and the output (d) of the calculating means 6 and detector 5 and outputs it to a digital controller 3. The controller 3 drives a motor 2 to position the head 1 at a target data track. Consequently, a feedback control system is constituted and excellent follow-up characteristics can be realized even at low sampling frequency.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic head positioning control device used in a floppy disk device using a sector servo system.

[Conventional technology]

In recent years, the capacity of floppy disk devices has been increased by narrowing the track pitch using a sector servo system. As is well known, the sector servo method is such that information regarding the position that the magnetic head should follow on the magnetic disk surface is recorded in advance at the beginning or end of the sector, and this information is reproduced by the magnetic head as a position error signal. This is a positioning control method based on so-called sample value information, in which the magnetic head is positioned on the target data track.

However, when applying the sector servo method,
For the purpose of securing a large data area, the number of information regarding positions that can be recorded in advance on the surface of a magnetic disk cannot be increased so much, and at present, the number is around 30 per revolution of a data track. This means that, for example, if the rotation speed of the magnetic disk is 30 Orpm, the frequency at which the position error signal is obtained, that is, the sampling frequency, will be around 150 Hz, and therefore the bandwidth of the feedback control system will be around 15 Hz. .

Furthermore, it is known that the data track of magnetic disks used in floppy disk devices deforms into an ellipse due to changes in temperature and humidity. Therefore, the main component of the data track signal that the magnetic head should follow is 10 Hz. be.

In order to increase the track density, it is necessary to achieve tracking accuracy for a 10 Hz signal within a bandwidth of around 15 Hz.

As this method, Japanese Patent Application No. 60-234544 “
There is a control method as disclosed in "Digital Positioning Control Device for Magnetic Head".

[Problem to be solved by the invention]

The control method described in Japanese Patent Application No. 60-234544 has a digital filter in the control loop that generates a sine wave with the same frequency as the eccentric main component of the data track, thereby controlling the magnetic head's influence on the eccentric main component. This is a control method with improved tracking accuracy. However, in order to set the sampling frequency for obtaining position errors as high as possible in order to widen the bandwidth of the control system, the data length per sector is fixed at, for example, 512 bytes, which deteriorates format efficiency. There was a problem.

The present invention was devised in view of the above problems, and the data length per sector is 1024 bytes, etc.
It is an object of the present invention to provide a magnetic head positioning control device for a magnetic disk device that can realize good target data track position tracking characteristics of a magnetic head even when the sampling frequency becomes low as a result.

[Means to solve the problem]

The present invention includes: a position error detector that obtains a position error signal indicating a difference between a target position to be followed by a magnetic head and the magnetic head position at each predetermined sampling time; and a motor that drives the magnetic head. A magnetic head positioning control device for a magnetic disk drive, comprising: a motor position detector that detects the position of the motor; and a magnetic head positioning controller that receives an output from the position error signal detector and outputs a drive signal to the motor. a target position calculation means for calculating a target data track position from the output of the position error detector and the output of the motor position detector; and a position error between the sampling times upon receiving the output of the target position calculation means. The present invention is characterized by comprising a position error interpolation means for interpolating signals.

[Effect]

The magnetic head positioning control device of the present invention interpolates the position error signal for each sampling time obtained from the position error detection means with the output of the target position calculation means, thereby achieving a good magnetic head position even under a low sampling frequency. Enables tracking of data track position.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings.

However, in the following explanation, signal names and signal values are expressed by the same symbol.

FIG. 1 is a block diagram showing the configuration of a magnetic head positioning control device for a magnetic disk device using a sector servo system according to an embodiment of the present invention.

This magnetic head positioning control device includes a position error detector 4 that obtains a position error signal indicating the difference between the target position to be followed by the magnetic head 1 and the position of the magnetic head l at every predetermined sampling time, and Target position calculation that calculates a target data track position from the motor 2 that drives the motor 1, the motor position detector 5 that detects the position of the motor 2, the output of the position error detector 4, and the output of the motor position detector 5. means 6, a position error interpolation means 7 which receives the output of the target position calculation means 6 and interpolates a position error signal between sampling times, and a digital means which receives the output of the position error interpolation means 7 and outputs a drive signal to the motor 2. A controller 3 is provided. “The target position calculation means 6 and the position error interpolation means 7 are constituent elements that characterize the present invention, and are added to the positioning control system of the magnetic head.

Next, the operation of this embodiment will be explained.

Let T be the sampling time. Here, for the sake of simplicity, a case will be described in which a sampling time of 1/2 is realized. Also, let S be the number of sectors.

The position error detector 4 generates a position error signal e from the signal reproduced by the magnetic head 1 at every sampling time T. This position error signal e is input to the target position calculation means 6 and the position error interpolation means 7. The output C of the position error interpolation means 7 is input to a digital controller 3 as described in Japanese Patent Application No. 60-234544. The digital controller 3 generates a control signal U for the motor 2, drives the motor 2, and positions the magnetic head 1 on a target data track. In this way, a feedback control system is constructed.

The motor position detector 5 detects the motor position and outputs a detected value d.
is sent to the target position calculation means 6 and position error interpolation means 7.

The target position detecting means 6 generates a target position r for every 1/2 hour of the sampling time from the position error signal value e for every sampling time T and the motor position signal value d. When the position error signal value at sampling time kT is e(kT) and the output of the motor position detector 5 is d(kT), the target position r(kT) is calculated by the following equation.

r (kT)=e (kT)+d (kT) (
1) In addition to calculating the target position r (kT) for each sampling time, the target position calculation means 6 calculates the target position r (k T +0.57) between sampling times. When calculating the target position twice the number of sectors S,
Target position r (kT
), for example, by the following calculation.

r (kT+o, 5T) = 0.5[0,5T (r (kT) −r (kT
−T) )+o,sT” (r (kT+T) −r
(kT+2T) ) ]...(2) The position error interpolation means 7 calculates the value every 1/2T from the output e of the position error detector 4, the output r of the target position calculation means 6, and the output d of the motor position detector 5. A position error signal is generated and output to the digital controller 3.

The position error interpolation means 7 calculates the position error signal e (kT) obtained from the position error detector 4 at every sampling time T.
Use as is. The position error signal value e (k T +0.5T) between samplings is calculated from the output r of the target position calculation means 6 and the output d of the motor position detector 5 as shown in the following equation.

e (kT+0.57) = r (kT+0.5T)-d (kT+0.57)
(3) The digital controller 3 generates a control signal U for the motor 2, drives the motor 2, and positions the magnetic head 1 on the target data track.

In the embodiments described above, the digital controller 3.degree. target position calculation means 6 and position error interpolation means 7 can be realized programmatically by an arithmetic element such as a microprocessor.

In the above embodiment, a case has been described in which the position error signal is interpolated at every half of the sampling time T, but interpolation at other times can also be performed.

〔Effect of the invention〕

As described above, according to the present invention, by adding the target position calculation means and the position error interpolation means to the positioning control system of the magnetic head, even under a low sampling frequency, a high sampling frequency can be simulated. A control system can be configured.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention. 1...Magnetic head 2...Motor 3...Digital controller 4...Position error detector 5...Motor position detector 6...Target position calculation means 7...Position error interpolation means

Claims (1)

[Claims] (1) a position error detector that obtains a position error signal indicating the difference between the target position to be followed by the magnetic head and the magnetic head position at every predetermined sampling time;
The magnetic head positioning controller includes a motor that drives the magnetic head, a motor position detector that detects the position of the motor, and a magnetic head positioning controller that receives the output of the position error signal detector and outputs a drive signal to the motor. A magnetic head positioning control device for a magnetic disk device, comprising: a target position calculation means for calculating a target data track position from an output of the position error detector and an output of the motor position detector; and an output of the target position calculation means. A magnetic head positioning control device comprising: position error interpolation means for interpolating a position error signal between the sampling times.