JPH0289264A - Method for controlling head positioning - Google Patents

Abstract

PURPOSE:To speed up head positioning by switching coarse control to fine control when a servo head arrives at a position separated from an objective track by a previously determined distance by coarse control. CONSTITUTION:When the servo head 6 arrives at the previously determined position from the center of the objective track, a track crossing generating circuit 14 sends a crossing pulse, so that a control means 16 sends a switching signal to an amplifier circuit 4 to drive a switch arranged on the input side of the circuit 4 and switch coarse control to fine control. Namely, when the servo head 6 arrives at the position separated by the previously determined distance, the coarse control is switched to the fine control and the fine control unstabilized by the influence of speed unmatching and switching noise due to switching can be stabilized. When the servo head 6 is positioned on the center of the objective track, the waiting of decision in the completion of positioning for a fixed time is made unnecessary by deciding the completion of position. Consquently, speed-up of head positioning can be attained.

Description

[Detailed Description of the Invention] [1 Already Required] Regarding a head positioning control method for rapidly positioning a head in a target cylinder in a disk device, the purpose of this invention is to meet the demand for high-speed head positioning, and to provide coarse control and fine control. In a disk device that positions the head at a target cylinder using The head is moved by coarse control, and when the head reaches the switching point, the head movement control is switched from coarse control to fine control, and in fine control, from the switching point to the target position,
The head is positioned at the target position by setting a virtual target position that changes with a predetermined time and controlling the head so that the difference between the constantly changing virtual target position and the current position of the head becomes zero. composition.

[Industrial application field]

The present invention relates to disk devices such as magnetic disk devices and optical disk devices, and particularly to a head positioning control method for positioning a head in a target cylinder at high speed.

For example, a magnetic disk drive usually has a magnetic disk composed of a plurality of magnetic disk disks depending on the storage capacity, and both sides of each magnetic disk disk are used as data recording surfaces, and a head is provided for each data recording surface. There is. This head is simultaneously positioned on each track of the target cylinder to write/read data.

In this case, one of the data recording surfaces is used as a servo surface for recording servo information, and the positioning of the head is controlled by reading the servo information recorded on this servo surface.

In other words, when a target cylinder for positioning the head is specified from a host device, the distance from the current position of the head to the target cylinder is calculated, the head is moved at high speed at first, and then the head is moved based on the servo information read by the servo head. After detecting the position of the head and moving it a predetermined distance, coarse control is performed to reduce the head movement speed as it approaches the target cylinder, and when it is near the target cylinder, it switches to fine control to achieve precise positioning. controls.

Incidentally, as the speed of computers connected to such disk devices increases, there is a demand for head positioning to be performed at high speed in order to increase the processing efficiency of data transfer between the disk devices and the disk devices.

[Conventional technology]

FIG. 5 is a block diagram explaining the conventional technique, and FIG. 6 is a flowchart explaining the operation of FIG.

As shown in FIG. 6 (■), when the target cylinder is instructed by the host device, the processor l calculates the distance from the current position of the servo head 6 and moves the servo head 6 as shown in FIG. 6 (■). The number of tracks is stored, and a target speed for moving the rod 6 to the servo is determined and set in the speed error detection circuit 3. Then, a seek control signal is sent to the speed detection circuit 2 to start moving the servo head 6 by coarse control, as shown in FIG.

The speed error detection circuit 3 detects an error between the moving speed of the servo head 6 detected by the speed detection circuit 2 and the target speed given from the processor 1, and controls a signal for driving the amplifier circuit 4. Therefore, the amplifier circuit 4 uses this drive signal to
A driving current is supplied to the motor 5, and the motor 5 moves the servo head 6.

The servo head 6 reads servo information from the servo surface and sends it to the position signal generation circuit 7. The position signal generation circuit 7 sends a signal indicating the position of the servo head 6 to the speed detection circuit 2 via the differentiating circuit 15, and the control current detection circuit 13 detects the drive current supplied to the motor 5 and outputs a signal indicating the position of the servo head 6 to the speed detection circuit 2. Send to 2.

The speed detection circuit 2 detects the moving speed of the servo head 6 based on the position signal of the servo head 6 inputted through the differentiation circuit 15 and the current value for driving the motor 5 sent out by the control current detection circuit 13. The signal is sent to the speed error detection circuit 3.

The track crossing generation circuit 14 generates a crossing pulse every time the servo head 6 crosses between tracks, based on the servo information sent by the position signal generation circuit 7, and notifies the processor 1 of the generated crossing pulse. Processor l is the 6th
As shown in Figure ■, the reception of this crossing pulse is monitored, and when this crossing pulse is received, the sixth
As shown in Figure 6, the stored number of tracks to be moved is reduced by 1, and the target speed corresponding to the remaining number of tracks is sent to the speed error detection circuit 3, and the number of tracks to be moved is determined as shown in Figure 6, ■. Check to see if it is O.

If the number of tracks to be moved is not O, the process returns to the step of monitoring the reception of the crossing pulse, and when the number of tracks to be moved is 0, the processor 1 is set to the phase shown in FIG.
As shown in FIG. 2, the speed detection circuit 2 monitors the transmission of the deceleration end signal. The speed detection circuit 2 sends out a deceleration end signal when the moving speed of the servo head 6 falls below a predetermined threshold.

Therefore, when the processor 1 receives this deceleration end signal, it determines that the servo head 6 has reached the vicinity of the target track.

Coarse control is performed in this way, and the servo head 6
is approximately positioned at the target track on the servo surface, and reaches a position 2 to 3 μm away from the center of the target track, for example.

When the processor 1 receives the deceleration end signal, it sends a switching signal to the amplifier circuit 4, as shown in FIG. let That is, the receiving circuit of the amplifier circuit 4 is switched from the speed error detection circuit 3 side to the position error generation circuit 12 side.

The position signal created by the position signal creation circuit 7 is passed through the filter 8.
Noise is removed from the signal, and the signal is sent to the amplifier circuit 9, the integration circuit 10, and the differentiation circuit 11. The position error generating circuit 12 uses the position signal amplified by the amplifier circuit 9, the position integral signal sent out by the integrating circuit 1O, and the position differential signal sent out by the differentiating circuit 11 to cause the servo head 6 to precisely center the target track. A position error signal is sent to the amplifier circuit 4 so as to be positioned at the position.

As shown in FIG. 6, the processor 1 monitors when the position signal generating circuit 7 sends out an on-track signal. The position signal generating circuit 7 sends an on-track signal for a certain period of time or more when the servo head 6 enters within an allowable error range from the center of the track.

Therefore, when the processor 1 receives the on-track signal for a certain period of time or more, it determines that the head positioning by fine control is completed.

The offset generation circuit 19 outputs an offset amount to the position signal generation circuit 7 based on instructions from the processor 1 when performing an offset seek.

[Problem to be solved by the invention]

As described above, conventionally, the coarse control is used to position the vehicle approximately on the target track, and then the fine control is used to precisely position the vehicle on the target track.

FIG. 7 is a diagram illustrating conventional head tracing.

If we take the position on the vertical axis and the time on the horizontal axis, the servo head 6 is brought close to the center of the target track (2) by coarse control as shown in Figure 7 (2), and is 2 to 3 μm from the center of the target track (2).
The servo head 6 reaches a position m away, and as described above,
When the moving speed of the servo head 6 falls below the dark value and the speed detection circuit 2 notifies the end of deceleration, the processor 1
Switch to fine control at the point indicated by the switching point in the figure.

This switching is performed on the condition that the speed of the servo head 6 is completely zero. However, in reality, although the speed of the servo head 6 is low, below the dark value, it is not zero, so the above conditions and speeds are unmanifested at the time of switching, and as shown in FIG. After overrunning the center ■ of the truck, it vibrates across the center ■ of the target trunk and gradually positions itself at the center ■ of the target trunk.

Furthermore, when switching to fine control, a switch (not shown) on the input side of the amplifier circuit 4 is switched from the speed error detection circuit 3 side to the position error generation circuit 12 side to shift from coarse control to fine control. Switching noise occurs.

This switching noise is caused by the noise generated by the switching device itself and the fact that the fine control system is not operating until the switch is switched from coarse control to fine control, so the voltage of the servo control system is not connected smoothly. Due to the influence of this noise, it takes time for the fine control system to stabilize.

Therefore, as shown in Fig. 6 @, positioning is not completed until a hiton track signal is received for a certain period of time.
There is a problem in that it is difficult to shorten the time it takes to complete positioning, and it is not possible to meet the demand for faster head positioning.

In view of these problems, the present invention prevents overruns caused by unmatched speeds by switching to fine control when the speed of the servo is not zero, and furthermore avoids the effects of switching noise, and when an on-track signal is received. The purpose of this invention is to make it possible to complete positioning without waiting for a certain period of time, and to meet the demand for faster head positioning.

[Means to solve the problem]

FIG. 1 is a block diagram of the principle of the present invention, and FIG. 2 is a diagram explaining the present invention in detail.

The same reference numerals as in FIG. 5 indicate the same functions. Control means 1
As explained in FIG. 5, when the servo head 6 reaches a position a predetermined distance MM from the target track by coarse control, it switches to fine control.

That is, if the vertical axis in FIG. 2 is the position and the horizontal axis is the time, as shown in FIG. When the track crossing generation circuit 1 is reached, the track crossing generation circuit 1
4 sends out a crossing pulse, the control means 16
sends a switching signal to the amplifier circuit 4, operates a switch (not shown) provided on the input side of the amplifier circuit 4, and switches to fine control.

At this time, the control means 16 sends a virtual target signal to the position signal generation circuit 17 so as to position the servo head 6 at a preset virtual target position shown in FIG.

As shown in the figure, the distance between this virtual target position (■) and the center (■) of the target trunk changes over time, and when the servo head 6 reaches the center (■) of the target track, the virtual target position is slightly different from the target position. , so as to reduce the speed of the servo head 6 when switched to fine control, and send out a virtual target signal such that the speed of the servo head 6 becomes zero when the servo head 6 reaches the center of the target track. is set in advance and superimposed on the position signal sent out by the position signal generation circuit 17.

Therefore, when the servo head 6 switches to fine control,
A virtual target signal that positions you at a virtual target position that changes sequentially over time slows you down and moves you to the center of the target trunk.
When the position is reached, the speed becomes zero and fine control is completed.

[Effect]

With the above configuration, the control means 16 switches to fine control when the servo head 6 reaches a position separated by a predetermined distance AI from the target track.
Since the deceleration operation is performed by fine control when the speed of the servo head 6 is not zero, overrun due to unmatched speed due to switching can be suppressed, and furthermore,
The influence of switching noise can be avoided.

That is, conventionally, coarse control was switched to fine control after the servo head 6 was positioned substantially on the target track. Therefore, considering the time it takes for the fine control system to stabilize due to unmatched speeds and switching noise, it is necessary to keep the fine control system stable for a certain period of time or more after switching to fine control, as explained in Figure 5. After receiving the on-track signal, it is determined that positioning is complete.

In the present invention, when the servo head 6 reaches a position a predetermined distance away, the fine control system is switched to fine control n, and the fine control system, which has become unstable due to speed unmatching due to switching and the influence of switching noise, is stabilized. When the servo head 6 is positioned at the center of the target track, it is determined that the positioning is completed, thereby eliminating the need to wait for the determination of the completion of positioning for a certain period of time. Therefore, the head can be positioned at high speed.

〔Example〕

FIG. 3 is a block diagram of a circuit showing one embodiment of the present invention.
FIG. 4 is a flowchart illustrating the operation of FIG. 3.

The same reference numerals as in FIG. 5 indicate the same functions. When the target cylinder is instructed by the host device as shown in FIG. 4 (■), the processor 18 calculates the distance from the current position of the servo head 6 and moves the servo head 6 as shown in FIG. 4 (■). In addition to memorizing the number of trunks, the servo head 6
A target speed for moving the is determined and set in the speed error detection circuit 3. Then, a switch (not shown) of the amplifier circuit 4 is connected to the output side of the speed error detection circuit 3, and a seek control signal is sent to the speed detection circuit 2. As shown in FIG. 6 starts moving.

The speed error detection circuit 3 detects an error between the moving speed of the servo head 6 detected by the speed detection circuit 2 and the target speed given from the processor 18, and sends out a signal to drive the amplifier circuit 4. Therefore, the amplifier circuit 4 supplies a drive current to the motor 5 based on this drive signal, and the motor 5 moves the servo head 6.

The servo head 6 reads servo information from the servo surface and sends it to the position signal generation circuit 17. Position signal generation circuit 17
sends a signal indicating the position of the servo head 6 to the speed detection circuit 2 via the differentiation circuit 15, and the control current detection circuit 13 detects the drive current supplied to the motor 5 and sends it to the speed detection circuit 2. .

The speed detection circuit 2 detects the moving speed of the servo head 6 based on the position signal of the servo head 6 inputted through the differentiation circuit 15 and the current value for driving the motor 5 sent out by the control current detection circuit 13, and determines the speed. It is sent to the error detection circuit 3.

The track crossing generating circuit 14 generates a crossing pulse every time the servo head 6 crosses between the track and the trunk based on the servo information sent by the position signal generating circuit 17, and notifies the processor 18 of the crossing pulse. processor 18
As shown in Figure 4 (■), monitors the reception of the crossing pulse, and when this crossing pulse is received, the stored moving track number is decreased by 1 as shown in Figure 4 (■).
Then, the target speed corresponding to the number of remaining tracks is sent to the speed error detection circuit 3, and as shown in FIG. 4, it is checked whether the remaining number of trunks to be moved is 1.

If the remaining number of tracks is not 1, the process returns to the step of monitoring the reception of the crossing pulse, and when the remaining number of tracks to be moved becomes 1, the processor 18 starts the track crossing generation circuit 14 as shown in FIG. Monitor the sending of the crossing pulse. Then, when the processor 18 receives this crossing pulse,
It is determined that the servo head °6 has reached a preset distance from the center of the target track, for example, a position separated by 1/2 trunk, and sends a switching signal to the amplifier circuit 4, and the built-in switching The controller is connected to the output side of the position error generating circuit 12, and coarse control is switched to fine control as shown in FIG.

The processor 18 shifts to fine control and also instructs the virtual target position generation circuit 20 to generate a virtual target signal based on a predetermined virtual target position as shown in FIG. 17, and superimposed on the position signal sent by the position signal generating circuit 17 in order to decelerate the servo head 6 as explained in FIG.

That is, for example, a, b, c, d in FIG.

As shown in FIG. 2, a virtual target signal is created based on the distance between the virtual target position and the servo head 6, which changes with time,
The position signal generation circuit 17 is caused to send out the signal at predetermined intervals.

The position signal created by the position signal creation circuit 17 is converted into a position signal that positions the user at the virtual target position using the virtual target signal, and after noise is removed by the filter 8, the position signal is sent to the amplifier circuit 9, the integration circuit IO, and the differential circuit. The signal is sent to circuit 11. The position error generation circuit 12 positions the servo head 6 at a virtual target position based on the position signal amplified by the amplifier circuit 9, the position integral signal sent out by the integrating circuit 10, and the position differential signal sent out by the differentiating circuit 11. The position error signal is sent to the amplifier circuit 4 as shown in FIG.

As shown in FIG. 4O, the processor 18 monitors the output of the on-track signal by the position signal generation circuit 17, and upon receiving the on-track signal, immediately determines that the head positioning by fine control has been completed.

Although the virtual target position generation circuit 20 is used in this embodiment, this function may be provided in the processor 18 and used by connecting the offset generation circuit 19 described in FIG. 5 as shown by the dotted line.

〔Effect of the invention〕

As explained above, the present invention avoids the influence of switching noise that occurs when switching from coarse control to fine control,
When the on-track signal is received, head positioning is immediately considered complete and head positioning is performed at high speed.
Data transfer processing efficiency between a computer and a magnetic disk device can be improved.

[Brief explanation of drawings]

Fig. 1 is a block diagram of the principle of the present invention, Fig. 2 is a diagram explaining the invention in detail, Fig. 3 is a block diagram of a circuit showing an embodiment of the present invention, and Fig. 4 is the operation of Fig. 3. Flowchart explaining the fifth
FIG. 6 is a block diagram explaining the conventional technique, FIG. 6 is a flowchart explaining the operation of FIG. 5, and FIG. 7 is a diagram explaining conventional head tracing. In the figure, 1.18 is a processor, 2 is a speed detection circuit, 3 is a speed error detection circuit, 4.9 is an amplifier circuit, 5 is a motor,
6 is a servo head, 7.17 is a position signal generation circuit, 8 is a filter, 10 is an integration circuit, 11.15 is a differentiation circuit, 12 is a position error generation circuit, 13 is a control n
14 is a track crossing generation circuit; 16 is a control means; 19 is an offset generation circuit; and 20 is a virtual target position generation circuit. Rime 8 Akira's 1t Rikitsubo and 3 many days a month A cow about 2 days! 4 疋釆の△...／Tote Shi-nu and Tora Taku Hizuki? jru stamp wa■

Claims (1)

[Claims] In a disk device that positions a head (6) at a target cylinder using coarse control and fine control, switching between coarse control and fine control is provided at a position a predetermined distance away from the target position. point, and move the head (6) using coarse control until it reaches the virtual target position, and when the head (6) reaches the switching point, move the head (6) from coarse control to fine control. In fine control, a virtual target position is set that changes with a predetermined time from the switching point to the target position, and the constantly changing virtual target position and the current position of the head (6) are set. A head positioning control method characterized in that the head (6) is positioned at a target position by controlling the head (6) so that the difference from the position becomes zero.