JPH02118979A - Head positioning controller for disk drive - Google Patents

Abstract

PURPOSE:To make the positioning control stable by using an external force compensation value stored corresponding to the track position and driving an actuator of a head. CONSTITUTION:An external force compensation value to a RAM 17 is stored prior to the start of using a disk drive. That is, an output of a D/A converter 19 is made zero and the loop is made stable by using a designation signal of an optional track position from a cable 12. Thus, a control signal compensating a torque external disturbance due to an elastic repulsion force of the cables 13, 14 is outputted from a control circuit 11, the signal is digitized by an A/D converter 16 and stored in the RAM 17 at an address corresponding to the track position from a photosensor 10. An external force compensation in response to the track position from the sensor 10 is read from the RAM 17 at the drive of a voice coil motor 6 in the case of in-operation and the value is added to the control signal at the circuit 11 via the D/A converter 19. Thus, the control to the torque external disturbance is not required by the circuit 11 and stable control is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a head positioning control device for a disk drive such as a hard disk device used in a computer.

[Summary of the invention]

The present invention relates to a head positioning control device for a disk drive, which detects an external force applied to an actuator, stores a compensation value corresponding to this external force, and uses this stored value to improve the stability of control operation. be.

[Prior Art] In a disk drive such as a hard disk device, a voice coil motor is generally used as an actuator for positioning a head.

That is, FIG. 2 shows an example of the mechanism of a disk drive, in which a hard disk (1) is rotated at high speed by a spindle (2). A head (3) is provided facing the recording surface of this disk (1), and this head (3) is attached to a helad arm (4), and the middle of this head arm (4) is a rotating shaft ( 5),
The other end is driven by a voice coil motor (6) to move the head (3) to a desired position in the radial direction of the disk (1). The voice coil motor (6) includes a stator portion (6a) such as a permanent magnet and yoke fixedly arranged on a case (not shown), etc., and a drive coil (6b) provided at the other end of the head arm (4). Consisted of.

A second arm (7) is also provided which is driven integrally with the Herad arm (4), and a scaler (8) for position detection is provided at the end of this arm (7). Further, a circuit board (9) is provided which is fixedly arranged in a case etc., and this board (9) is provided.
9) Optical sensor 00 at the position corresponding to the upper scaler (8)
) is provided. This optical sensor 00) and scaler (8
), a detection signal corresponding to the track position of the head (3) is formed.

A detection signal from this optical sensor 0ω is supplied to a control circuit (11) on the substrate (9). Also, an external computer (
A signal indicative of the target track position from a device (not shown) or the like is supplied to a control circuit (11) on a circuit board (9) through an input/output cable (02). And this control circuit (11)
A control signal from the drive coil (6b) is supplied to the drive coil (6b) through the flexible cable (03).

As a result, in this device, the head (3) is moved to the target track position indicated by an external computer, etc., and the track position is detected by the optical sensor 00) and this detection signal is fed banked to the head (3). (
3) positioning to a desired track position is performed.

With this head (3) positioned,
) is supplied to the circuit board (9) via the flexible cable circle, and output to an external computer etc. through the input/output cable (02). In addition, the signal supplied through the input/output cable (02) is connected to the circuit board (9).
) is supplied to the head (3) via a flexible cable (04), and recording is performed. In this way, signals from a computer or the like are recorded and reproduced on the hard disk (1).

[Problem to be solved by the invention]

By the way, in the above-mentioned device, a flexible cable q■04) is connected between the fixedly arranged circuit board (9), the head (3) on the helad arm (4), and the drive coil (6b).
The head arm (4) can be freely rotated by bending this cable.

However, in this case, when the bending ratio of the flexible cable 03) 04) changes when the voice coil motor (6) is driven, an elastic repulsion force is generated in this cable, and this force becomes a torque disturbance and the voice coil motor (6) ) may have an adverse effect on

That is, FIG. 3 is a block diagram showing the configuration of the head positioning control device, in which a signal corresponding to the target position from the cable θ2) is supplied to the control circuit (10), and a signal from the control circuit (II) is supplied to the control circuit (10). The signal is from the voice coil motor (
VCMH6). For this reason, the head arm (4
) is moved, this moving position is detected by the optical sensor 00), and this detection signal is supplied to the control circuit (11). As a result, the detection signal from the optical sensor θ0) and the cable 0
Control is performed so that the target position signal from 2) coincides with the target position signal, and the head (3) is positioned at the target track position.

However, in this device, the voice coil motor (6)
and head arm (4) with flexible cable 0
3) A torque disturbance due to the elastic repulsive force of 04) is applied.

Therefore, in this device, the feedback loop for positioning control performs control including the above-mentioned torque disturbance, which requires a long time (seek time) until the positioning position is reached and stabilized. There was also a risk that stability would be impaired.

In contrast, the applicant of the present application has proposed that by first bringing the bent part of the flexible cable 03) into contact with a fixed part around the rotation axis (5), the elastic repulsion force can be applied to the rotation axis (5). We propose a countermeasure to prevent torque disturbance by absorbing the torque (
(Refer to Japanese Patent Application Laid-open No. 11760/1983). However, even if such measures are taken, the torque disturbance caused by the flexible cable cannot be completely eliminated, and the adverse effects of the remaining disturbance cannot be ignored.

This application has been filed in light of these points.

[Means for Solving the Problems] The present invention includes an actuator (voice coil motor (6)) that positions the head (arm (4)), and a position detection means (scaler (8)) that detects the track position of the head. ), an optical sensor θ0)), an external force detection means (control circuit (II)) for detecting an external force applied to the actuator corresponding to the track position of the head, and an external force compensation value corresponding to the detected external force. Corresponds to the track position detected by the above position detection means (address generation circuit 08))
and a storage means (RAMQ7)) for storing the head position by driving the actuator based on the external force compensation value read from the storage means corresponding to the track position. This is a head positioning control device for a disk drive.

[Operation] According to this, the following 1. corresponds to the track position. By driving the actuator using the external force compensation value α, adverse effects such as torque disturbance on positioning control are removed, and extremely good and stable control can be performed.

(Example) By the way, the elastic repulsion force of the flexible cable θ3) θ4), which causes the above-mentioned torque disturbance, is determined by the rotational position of the herad arm (4), that is, the head ( 3) corresponds to the track position.

Therefore, in FIG. 1, the control signal supplied from the control circuit (11) to the voice coil motor (6) is supplied to the AD conversion circuit 00 through the low-pass filter 05), and the converted digital value is supplied to the RAM Q7). .

Further, a signal corresponding to the trunk position from the optical sensor θ0) is supplied to the address generation circuit (18), and the generated address is supplied to the RAM (17). Furthermore, RAMθ
The signal from '7) is supplied to the DA conversion circuit 09), and the converted analog signal is supplied to the control circuit (11).

In this device, when starting to use the disk drive, the external force compensation value is stored in the RAMG7) prior to use. That is, in the configuration shown in the figure, the output of the DA conversion circuit 09) is set to "0", a signal specifying an arbitrary track position is supplied from the cable θ, and in this state, the loop is stabilized after a sufficient period of time. The control circuit (11) outputs a control jII signal that compensates for the torque disturbance caused by the cable (+3) 041, etc., and this control signal is digitized by the AD conversion circuit 00 via a low-pass filter 05), and then output to the optical sensor ( The external force compensation value corresponding to each track position is stored in RAM 07) by the address corresponding to the track position from 10).This operation is performed for all track positions as necessary, for example, and the external force compensation value corresponding to each track position is stored in RAM 07).

As a result, during use, when the voice coil motor (6) is driven, an external force compensation value corresponding to the track position from the optical sensor GQ) is read out from the RAMQ7), and this value is converted into an analog by the DA conversion circuit (circle). +11 circuits (11)
By adding the control j11 signal at the control circuit (
In 11), the control j'fl against torque disturbance becomes unnecessary,
Extremely good and stable control is achieved by performing only positioning control.

That is, according to the above-mentioned device, by driving the actuator using the external force compensation value stored in correspondence with the track position, the adverse effects of positioning control and torque disturbance etc. are removed, resulting in extremely good and stable performance. It is possible to perform various controls.

In addition, in the above-mentioned apparatus, since the control becomes stable, higher-speed positioning (seek) is possible, and it is also possible to cope with higher-speed computers.

Furthermore, in the above-mentioned apparatus, the external force compensation values can be stored in the RAM for all track positions or for intermittent 1-rack positions, and the values can be interpolated between them. Conversely, control can be performed even more smoothly by storing not only all track positions but also positions between them.

Furthermore, the data may not be stored in the RAM each time it is used, but a backup means may be provided to normally use the previous value, and the data may be stored only when changes occur over time or in the external environment.

Therefore, this device can respond to changes over time and changes in the external environment.

Further, by compensating for torque disturbance, the degree of freedom in terms of the material of the flexible cable can be increased, and the degree of freedom in terms of structure such as rotation and linear movement of the head drive can also be increased.

FIG. 3 is a diagram for explaining the SF drive, and FIG. 3 is a diagram for explaining the conventional technology.

(1) is the disk, (2) is the spindle, (3) is the head, (4) is the -rad arm, (5) is the rotation axis, (6)
is the voice coil motor, (7) is the second arm, (8)
is the scaler, (9) is the circuit board, 0ω is the optical sensor, (1
1) is the control circuit, θ is the input/output cable, (13) 0
4) is a flexible cable, 05) is a low-pass filter, 06) is an AD conversion circuit, 0'7) is a RAM, 01 is an address generation circuit, and the side is a DA conversion circuit.

[Effects of the Invention] According to the present invention, by driving the actuator using the external force compensation value stored in correspondence with the track position, adverse effects such as torque disturbance on positioning control are eliminated, resulting in extremely good performance. Moreover, it became possible to perform stable control.

[Brief explanation of the drawing]

Claims (1)

[Scope of Claims] An actuator for positioning a head, a position detecting means for detecting a track position of the head, an external force detecting means for detecting an external force applied to the actuator corresponding to the track position of the head; storage means for storing an external force compensation value corresponding to the detected external force in correspondence with the track position detected by the position detection means, the external force compensation being read from the storage means in correspondence with the track position; A head positioning control device for a disk drive, which positions the head by driving the actuator based on the value.