JPS62137778A - Positioning method for magnetic head - Google Patents

Abstract

PURPOSE:To set a magnetic head at its normal position in a short time by shifting the side alignment differential of the magnetic head from the present head position via an open loop to minimize the position shift of the magnetic head and then shifting the magnetic head to a positioning servo loop. CONSTITUTION:When a magnetic head enters a servo loop immediately after the side is switched at a point (a) shown in the figure the correction amount of the first head position is shown by S1+S2. Then a microprocessing circuit 11 calculates the both-side alignment differences of magnetic heads 3 and 4 and a medium 1, i.e., the S1 shown in figure from the servo information on one or several ones of the fixed sectors of one or several tracks when the medium 1 is changed or when a fixed period of time passed with no change of the medium 1. Then the servo loop is stopped when the sides of both heads 3 and 4 are switched and the magnetic head is moved from the head positioning point (a) by an amount equal to the side alignment difference S1 via an open loop after the lead recovery time is secured in a side switching mode.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for positioning a magnetic head with respect to a floppy disk used in an auxiliary storage device for personal computers, word processors, measuring instruments, and the like.

Conventional technology Conventionally, in order to switch the side of the magnetic head during magnetic head positioning control for a floppy disk (hereinafter referred to as media), the servo loop is stopped and the side is switched to reduce the read recovery time of the head amplifier. After the magnetic head is removed, it immediately enters a servo loop for positioning the magnetic head.

Problems to be Solved by the Invention However, in the conventional method described above, in which the servo loop for positioning the magnetic head is entered immediately after switching the side of the magnetic head, the difference in alignment between the two sides of the magnetic head and the difference in the alignment between the two sides of the magnetic head are caused. Since there is a side alignment difference, in the worst case, the side alignment difference between the magnetic head and the medium is added, and the error in positioning the magnetic head becomes large immediately after the side switching of the magnetic head is performed. In such a case, the following problems occur.

(1) Although it depends on the performance of the head amplifier, it is possible to detect only one of the two servo information in each sector, and it is not possible to quantitatively measure the positional deviation of the magnetic head. The magnetic head must be qualitatively positioned to a position that can be measured quantitatively. Since this takes several sectors, the time required for side switching of the magnetic head increases.

(2) If the control amount for one magnetic head positioning is large, the gain of the actuator for magnetic head positioning must be increased, making it easier for oscillation to occur, resulting in a longer head switching time. Become.

The present invention solves these conventional problems, and provides a magnetic head positioning method that can shorten the side switching time of the magnetic head and perform stable magnetic head positioning control. It is intended to provide a method.

Means for Solving the Problems and Technical Means of the present invention for solving the above-mentioned problems is to eliminate alignment errors of magnetic heads on both sides in advance using servo information recorded in advance on tracks of a floppy disk. The magnetic head is positioned after the magnetic head is read and stored, and the magnetic head is moved by the above-mentioned alignment difference when changing the side of the magnetic head.

For production The effects of the above technical means are as follows.

In other words, when switching the side of the magnetic head/nod, first, the oven loop moves the side alignment difference of the magnetic head from the current head position to minimize the positional deviation of the magnetic head, and then the servo loop for positioning the magnetic head is used. Since the magnetic head position is shifted, the number of times the magnetic head position is corrected can be reduced (0 to 1.2 times), and the magnetic head can be positioned at the correct position in a short time.

Further, since the amount of positional deviation of the magnetic head is small, there is no need to increase the gain of the actuator for positioning the magnetic head more than necessary, and stable control of the magnetic head can be performed.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings. First, the positioning control system for the magnetic head will be explained.

In FIG. 1, numeral 1 denotes a floppy disk (hereinafter referred to as media), on which servo information is recorded in advance in each sector of each track, and is rotated by a spindle motor 2 at a constant speed. Magnetic heads 3 and 4 are provided on both sides of the medium 1, and are positioned relative to the medium 1 by a head actuator 5. 6 is a head amplifier that reads the magnetic signal from the magnetic head 3.4 and outputs the read data to the servo detection circuit 0. The servo detection circuit 10 detects servo information from the read data and sends the preamplifier 7,
The sample hold circuit 8 and the AD converter 9 are activated to transmit the amount of magnetic head positional deviation to the microprocessing unit (MPU) 11. Microprocessing unit 1 that memorizes this magnetic head misalignment
1 operates the above described head actuator 5 to position the magnetic heads 3 and 4 in accordance with the amount of positional deviation of the magnetic heads.

In the head positioning control system as described above, a case will be described in which side switching of the nozzles 3 and 4 to the magnetic side is performed.

In the media 1 to which the sector servo information has been written, the actual tracks over all the tracks have an off-track SO with respect to the regular track as shown in Figure 2 (as shown in this figure), and due to eccentricity when the media 1 is clamped, The magnetic head 3 on the O side and the magnetic head 4 on the 1st side have an alignment error Sl, and if the offset on the side is SO, then the magnetic head 3 on the O side and the magnetic head 4 on the 1st side have an alignment error of has an offset of 5o-)-8t, and the deviations relative to the eccentricity of the media 1 are considered to be approximately the same.Also, for all tracks, the actual amount of track deviation differs only in the off-track So. It is thought that they can be approximated with approximately the same shape.

Here, if the sides of the magnetic nodes 3 and 4 are switched at point a in FIG. The result is SL+82 in Figure 2. Therefore, when the media 1 is changed, or when a certain period of time has elapsed without being changed, the magnetic head 3.4 and the media 1 are The two-side alignment difference, ie, 81 in FIG. 2, is calculated by the microprocessing unit].11. Next, the magnetic head 3,
When the side switching is performed in step 4, the servo loop is stopped as shown in Figure 3 (at), and after taking the lead recovery time at the time of side switching as shown in Figure 3 (fil), the open loop is used to switch the side. The magnetic head is moved by the alignment difference Sl from the magnetic head positioning position at point a.If there is vibration of the magnetic head, the subsequent servo loop may become unstable, so after taking a settling time, , enters the servo loop.

If the time T shown in FIG. 3(b) is carried out within one sector.

The magnetic head position shift of the first servo loop after side switching only requires S2. In addition.

The read recovery time is sufficiently short compared to the open loop time and can be performed simultaneously, so it is not necessarily necessary.

Effects of the Invention As is clear from the above explanation, according to the present invention, when switching the side of the magnetic head, first the alignment difference of the side of the magnetic head is moved from the current head position using an open loop, and the position of the magnetic head is changed. Since the servo loop for positioning the magnetic head is shifted after minimizing the deviation, the amount of magnetic head position deviation during side switching is small, so side switching can be performed in a small number of sectors. . Furthermore, since the amount of magnetic head position deviation during side switching is small, the gain of the actuator for positioning the magnetic head can be lowered, oscillation phenomenon is less likely to occur, and stable positioning control of the magnetic head can be performed.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram showing a magnetic head positioning control system for explaining the magnetic head positioning method of the present invention, and FIG. 2 is a diagram showing the amount of positional deviation of a track on a floppy disk.
FIG. 3(a) is a diagram showing the timing of side switching, and FIG. 3(1)) is an enlarged view of section A thereof. 1...Media (floppy disk), 2...Spindle motor% 3...Magnetic head, 4...Head, 5...Actuator% 6...Head amplifier, 7...Preamplifier, 8 ...sample hold circuit, 9.・, AD converter, 10... Servo detection circuit, 11... Micro processing unit (M
PU). Name of agent: Patent attorney Toshio Nakao (1st person)
Figure 2

Claims (1)

[Claims] The alignment error of the magnetic heads on both sides is read in advance by the magnetic head using servo information recorded in advance along the track of the floppy disk, this is stored, and the magnetic head is moved by the above alignment difference when switching sides of the magnetic head. , a magnetic head positioning method characterized by positioning a magnetic head.