JPH05334817A - Disk device state prediction system - Google Patents

Abstract

PURPOSE:To suppress an adverse effect on a state predictor by the disturbance of an actuator. CONSTITUTION:The diagram shows a control system in its position following mode. In the diagram, (d) is the external disturbance against an actuator, (r) signifies the effect such as the eccentricity of a disk surface and (v) is a predicted speed. The predicted speed (v) is predicted by a position error information 18 between the disk surface and a head and a current sense information. Note that the value, which is made by subtracting the output information of an integrator 17 from the current sense information 12, is used by a predictor 15 and is made as a current sense information 21. The output information of the integrator 17 is stored in a memory 16 in order to use in a speed mode and in the speed mode the value which is made by subtracting the integrator output stored in the memory 16 from the current sense information 12 obtained from an actuator driving current, is made as the current sense information 21 of the predictor 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a disk device,
The present invention relates to a method for suppressing the influence of an actuator disturbance on a state estimator.

[0002]

2. Description of the Related Art A control system of a disk device generates a reference speed to be followed by the head according to a difference between a current position of the head and a target position, and a speed mode in which the head speed follows the reference speed. It has two control modes: a position following mode in which the head follows the target track.

The track access operation is realized by first moving the head to the vicinity of the target track in the speed mode, and switching from the speed mode to the position following mode at an appropriate time in the vicinity of the target track.

In the speed mode, the head speed is fed back and an actuator drive current proportional to the difference from the reference speed is generated. In the position tracking mode, PID
When control is used, the actuator is driven by adding three values, a value proportional to the position error information of the head, a value proportional to the speed information of the head, and a value proportional to the integrated value of the position error information of the head. Generating current.

However, since the head speed cannot be obtained by the disk device, the head speed is estimated based on the head position error information and the current sense information obtained by detecting the drive current of the actuator.

[0006]

In the conventional disk device, the head speed is estimated based on the head position error information and the current sense information. However, the relationship between the drive current and the head speed changes due to the influence of the disturbance on the actuator. However, it is difficult to accurately estimate the head speed.

[0007]

In the disk drive of the present invention, in the position following mode, the head speed and the head position error are small when the position deviation between the head center and the track center is smaller than a certain value. The drive current of the actuator is considered to be almost equivalent to the output of the integrator, and since the positional deviation between the head center and the track center is small, the disturbance to the actuator and the drive current are considered to be equivalent. Therefore, since it is considered that the drive current and the disturbance to the actuator are equivalent, the current used in the estimator is the value obtained by subtracting the integrated value of the obtained position error information from the current sense signal acquired for state estimation. By using the sense information, the influence of the disturbance of the actuator on the state estimation can be suppressed.

Further, in the speed following mode and the position following mode immediately after switching from the speed mode, when the position deviation between the head center and the track center is larger than a certain value,
Suppressing the influence of actuator disturbance on state estimation by using the value obtained by removing the integrated value of the position error information at the start of access operation from the current sense signal acquired for use in state estimation as the current sense information used by the estimator. can do.

[0009]

In the disk device of the present invention, the influence of disturbance on the actuator in state estimation is suppressed,
It becomes possible to perform more accurate state estimation.

[0010]

The present invention will be described below with reference to the drawings. 1 and 2 are block diagrams of a controller to which an embodiment of the present invention is applied, and FIG. 3 is a block diagram of a disk device.

In the disk device shown in FIG. 3, position error information of the head 2 can be obtained from the track center by the servo information 9 read from the disk surface 1. The position error signal generator 3 generates a position error signal 10 as a periodic signal for each track from the servo information 9 and inputs it to the controller 5. The signal 13 output from the controller 5 is the power amplifier 6
Is converted into a driving current 14 and output to the actuator 7. This drive current value is converted into a current sense signal 12 by the current detector 8 and input to the controller 5.

FIG. 1 shows the controller in the position following mode. d is the influence of disturbance on the actuator 7, r is the influence of eccentricity of the disk surface, and v is the estimated speed. Number of passing tracks 11 and position error signal 10
The speed v is estimated by the position error information 18 of the disk and the head obtained and the current sense information. However,
A value obtained by removing the output information of the integrator 17 from the current sense information 12 is used as the current sense information 21 used in the estimator 15. The PID controller drives the actuator 7 with a value proportional to the estimated speed information v obtained by the estimator 15, a value proportional to the position error information 18, and a value proportional to an integral value 22 of the position error information 18. The current 14 is generated. The integrated value 23 of the position error information 18 is stored in the memory 16 for use in the speed mode. Immediately after switching from the speed mode to the position tracking mode, the value of the memory 16 is used because the integrated value 23 has not converged sufficiently. The switching between the case of using the value of the memory 16 and the case of directly using the integrated value 23 is performed after detecting that the position error signal 10 has sufficiently converged.

FIG. 2 shows the controller in speed mode. Current sense information 12 as in the position tracking mode
And the position error information 18 is used to estimate the speed.
The current sense information used by the estimator 15 in the speed mode is the current sense information 12 obtained from the drive current 14 of the actuator 7 from the memory 1 in the position tracking mode.
The value 21 excluding the output 24 of the integrator 17 stored in 6 is used. The reference velocity generator 19 obtains the remaining distance of the access operation from the position error information 18, and obtains the reference velocity of the head based on the remaining distance. The estimated speed and the reference speed are compared, and the drive current 14 of the actuator 7 is obtained so that the head speed follows the reference speed.

[0014]

As described above, according to the present invention, the influence of disturbance on the actuator is suppressed in state estimation, so that more accurate state estimation can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment in a position tracking mode of the present invention.

FIG. 2 is a block diagram of an embodiment in a speed mode of the present invention.

FIG. 3 is a schematic diagram of a disk device of this embodiment.

[Explanation of symbols]

 10 Position Error Signal 12 Current Sense Information 14 Actuator Drive Current 17 Integrator 18 Position Error Information

Claims (2)

[Claims] 1. A head position error signal is integrated by an integrator, the speed of the head is estimated by a state estimator based on the position error signal and the drive current value of the actuator, and the position error signal is fed back to feed the head. In positioning control of a disk device that has a position tracking mode that follows the target track as one of the operation modes, in the position tracking mode, when the position deviation between the head center and the track center becomes smaller than a certain value, state estimation A state estimation method for a disk device, wherein the state is estimated by assuming a value obtained by subtracting the output of the integrator from the drive current value of the actuator acquired for use as the drive current value of the actuator. 2. A head by a state estimator that generates a reference speed to be followed by the head according to the difference between the current position of the head and a target position, and estimates the state based on the position error signal of the head and the drive current value of the actuator. A velocity mode in which the estimated velocity value follows the reference velocity, and the head position error signal is integrated by an integrator and the head velocity target value and the position error signal fed back by the state estimator are fed back to the target track. In the head positioning access operation in which head control is performed in two modes, a position tracking mode that causes the head to follow the position tracking mode, when the position deviation between the head center and the track center is greater than a certain value in the position tracking mode immediately after switching from the speed mode , Access operation start from the drive current value of the actuator acquired for use in state estimation. State estimation method of a disk device and performing the assumption that the state estimated value excluding the output of the integrator and the driving current value of the actuator when.