JPS63249981A - Magnetic head positioning device - Google Patents

Abstract

PURPOSE:To quickly position a head with a high precision by selecting the position signal, which is used for positioning control on an objective cylinder, at the time of starting access. CONSTITUTION:A positioning signal selecting circuit 9 determines the position signal, which is used for positioning control on the objective cylinder, at the time of starting access and turns on one analog switch 7 to send it to a position error amplifier 8 at the time of positioning control. The position error amplifier 8 sends the positioning control signal to a power amplifier 4 so that a magnetic head 2 is moved in the same direction if the selected signal has a negative value but the magnetic head is moved in the opposite direction if it has a posi tive value. The power amplifier 4 supplies a control current to a VCM 3 to move the magnetic head 2 so that the value of the positioning signal is 0. Thus, head positioning is quickly and stably controlled.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a positioning device for a magnetic head of a magnetic disk device that performs positioning control using a two-phase servo system, and in particular, to a positioning device that performs stable positioning control at high speed and with high precision. The present invention relates to a magnetic head positioning device that can perform magnetic head positioning.

[Prior art]

In a magnetic disk device equipped with a positioning control system using a two-phase servo system, when moving a magnetic head onto a target track for positioning, for example, Japanese Patent Laid-Open No. 60-1931
In the method described in Japanese Patent No. 75, if the moving speed of the magnetic head is low, a track crossing pulse is detected for each track, and if the moving speed is high, a track crossing pulse is detected for each track.
Track crossing pulses are detected every few tracks to detect the track address and position to the target track.

However, in this method, no consideration is given to the case where positioning control is performed at a position different from the target track due to the "side" or "edge" of the track crossing pulse.

[Problem that the invention seeks to solve]

In the above conventional technology, no consideration is given to the case where the track crossing pulse is crossed by 11 or 1' due to a defect in the magnetic disk while the magnetic head moves on the track. In particular, in magnetic disk drives that have increased speed and density, there is a risk that the magnetic disk drive may be incorrectly positioned at a position different from the target position.

The purpose of the present invention is to improve such problems and achieve high precision and
Another object of the present invention is to provide a magnetic head positioning device that can perform positioning operations at high speed.

[Means to solve the problem]

In order to achieve the above object, the magnetic head positioning device of the present invention is equipped with a positioning control system using a two-phase servo system, and when moving the magnetic head to a target track and positioning it, the positioning device uses a position signal to control the positioning. In a magnetic disk drive that performs positioning control, a means (amplifier) for selecting a position signal used for the above-mentioned positioning control at the start of access and determining whether or not a track that has entered positioning control is a target track; It is characterized in that it is equipped with means (amplifier, power amplifier) for automatically correcting track differences, and when positioning control is started at a position different from the target track, it automatically moves to the target track and performs positioning control.

[Effect]

In the present invention, by selecting the position signal used for positioning control in the target cylinder at the start of access, if the value of the position signal is O when entering the positioning control system from the speed control system, the position signal is on the target cylinder. In order to show that
If the value of the position signal is negative, the magnetic head is controlled to move in the same direction as the moving direction of the magnetic head, and if the position signal is a positive value, the control is performed to move in the opposite direction to the moving direction of the magnetic head.

In this way, positioning control is performed so that the value of the position signal becomes O, and the cylinder is positioned on the target cylinder.

For this reason, the “side” of the track crossing pulse
Even if positioning control is started at a position different from the target cylinder due to occurrence of "crossover", the correction can be automatically performed and positioning can be performed on the target cylinder.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram of a magnetic head positioning device in an embodiment of the present invention, FIG. 4 is an explanatory diagram of position signals in an embodiment of the present invention, and FIG. FIG. 3 is an explanatory diagram of a position signal used for positioning control on a cylinder. Note that the O mark in Figure 4 indicates ON TRACK.
Show location.

As shown in FIG. 1, the magnetic head positioning device of this embodiment includes a magnetic head 2, a VCM 3, a power amplifier 4, a position signal demodulator 5, an inverting operational amplifier 6, an analog switch 7,
It includes a position error amplifier 8 and a positioning signal selection circuit 9.

The magnetic head 2 reads servo data on the magnetic disk 1.

The position signal demodulator 5 creates position signals of a P-phase P signal (hereinafter abbreviated as P-F) and a Q-phase P signal (hereinafter abbreviated as Q-P) from the servo data, as shown in FIG. and sends it to an inverting operational amplifier 6 and an analog switch 7. Further, the inverting operational amplifier 6 creates P-N and Q-N from the sent P-P and Q-P position signals and sends them to the analog switch 7.

These P-P and Q-P have a phase delay of 90°, and by combining P-N and Q-N generated by the inverting operational amplifier 6, a four-phase position signal (P-P, Q- P, P-N, Q-N
) is created. Furthermore, at the positioning point of the target cylinder,
The value of the position signal is 0.

Further, the cylinders that can be positioned are different between the P phase and the Q phase. In other words, the track numbers that can be positioned in the P phase are 0, 2, 4, etc. ..., and the track numbers that can be positioned in the Q phase are 1, 3, 5 degrees, etc.

Furthermore, as shown in Fig. 5, even if the position can be positioned in P phase or Q phase, the positioning signal for FWD seek to advance the magnetic head and REV seek to return the magnetic head is determined by the polarity of the position signal. It is necessary to choose.

In this embodiment, the position signal used during positioning control is
At the start of access, select according to the target cylinder.

In addition, when positioning control is entered at the target cylinder due to the track crossing pulse, the value of the position signal of the positioning control system shows 0, and the track crossing pulse "sides" or "crosses", and the target cylinder If an attempt is made to position to a wrong cylinder that is different from the target cylinder, the position signal of the positioning control system will have a value that is different from that of the target cylinder, so the positioning control system will operate to set the value of the position signal to 0. .

The positioning signal selection circuit 9 determines a position signal to be used for positioning control in the target cylinder at the start of access, and also turns on one of the analog switches 7 and sends it to the position error amplifier 8 during positioning control.

If the selected position signal has a negative value, the position error amplifier 8 sends a positioning control signal (positional deviation signal) to the power amplifier 4 so that the magnetic head 2 moves in the same direction as the moving direction. Further, if the position signal has a positive value, a positioning control signal is sent to the power amplifier 4 so that the magnetic head 2 moves in the opposite direction to the moving direction.

The power amplifier 4 supplies a control current to the VCM 3 and moves the magnetic head 2 so that the value of the positioning signal becomes zero.

FIG. 2 is an explanatory diagram of positioning control when the track crossing pulse is multiplied by 1' in one embodiment of the present invention, and FIG. 3 is an explanatory diagram of the positioning control when the track crossing pulse is FIG. 6 is an explanatory diagram of positioning control when a "flank" occurs.

For example, as shown in FIG.
When positioning control is entered at a position further advanced than 2) (track number 13), since the positioning signal is a positive value, the magnetic head 2 is moved in the opposite direction to the moving direction and positioned on the target cylinder.

In addition, as shown in Figure 3, a "side" occurs in the track crossing pulse, and the position (track number 11) is located before the target cylinder (door rack number 12).
), the positioning signal is a negative value, so the magnetic head 2 is moved in the same direction as the movement direction,
Position on the target cylinder.

In this way, even if a "crossing" or "waving" occurs in the track crossing pulse, stable positioning can be performed on the target cylinder.

〔Effect of the invention〕

According to the present invention, during the movement of the magnetic head, a defect in the magnetic disk causes a track crossing pulse to be lost.
Even if the difference counter makes a counting error and enters positioning control at a position different from the target track, it is possible to move further to the target track and perform positioning.

Therefore, it is possible to perform stable positioning control at high speed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a positioning device for a magnetic head of 8 according to an embodiment of the present invention, and FIG. 2 is a positioning control when a track crossing pulse is interrupted in an embodiment of the present invention. FIG. 3 is an explanatory diagram of positioning control when a "flank" occurs in the track crossing pulse in one embodiment of the present invention, and FIG. 4 is an explanation of the position signal in one embodiment of the present invention. 5 are explanatory diagrams of position signals used for positioning control on the customer cylinder in one embodiment of the present invention. 1: magnetic disk, 2: magnetic head, 3: VCM. 4: Power amplifier, 5: Position signal demodulator, 6: Inverting operational amplifier, 7: Analog switch, 8: Position error amplifier,
9: Positioning signal selection circuit, P-N: P phase N signal, P-
P: P phase P signal, Q-N: Q phase N signal, Q-P: Q phase P
signal.

Claims (1)

[Claims] In a magnetic disk drive that is equipped with a positioning control system using a one- or two-phase servo system and performs positioning control using a position signal when moving a magnetic head onto a target track for positioning, the position signal used for the positioning control is A magnetic device characterized by comprising means for determining whether a track selected at the start of access and entering positioning control is a target track, and means for automatically correcting a track difference from the target track. Head positioning device.