JPH02154377A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To perform an optimum head positioning control even when a force constant, etc., of a motor are altered by detecting head moving acceleration, inferring characteristics of a mechanism part from it and changing a gain of an operational amplifier circuit in order to correct the characteristics. CONSTITUTION:Upon start-up, several times of a seek operation, i.e. the operation for moving an actuator by the motor 8 to position the magnetic head 2 on a track of a magnetic disk 1 is performed, and at this time, the moving acceleration of the magnetic head 2 is detected by an acceleration signal generating circuit 9 to be outputted as a moving acceleration signal. Based on this moving acceleration signal, a gain is calculated by a gain control circuit 10 so as to make open loop characteristics of a control system always constant, and based on a gain control signal to be outputted from the gain control circuit 10, the gain of the operational amplifier circuit 6 is changed to an optimum value. By this method, even when the force constant, etc., of the motor for moving the magnetic head are altered, the optimum head positioning control can be carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk device for recording and reproducing information, and more particularly to a magnetic disk device for controlling the positioning of a magnetic head with respect to a magnetic disc.

[Conventional technology]

5 is a block diagram showing the configuration of a head positioning control system in the conventional magnetic disk device shown in FIG. 4. FIG.

In the figure, 1 is a magnetic disk that records information and is rotated by a motor (not shown), 2 is a magnetic head that records and reproduces information on the magnetic disk 1, and 3 is the position of the magnetic head 2 with respect to the magnetic disk 1. A position signal generation circuit that detects information and outputs a head position signal; 4 is a speed that generates a moving speed signal of the magnetic head 2 (hereinafter referred to as head speed signal) based on the head position signal output from the position signal generation circuit 3; a signal generating circuit; 5, a target speed generating circuit that generates a target moving speed signal (hereinafter referred to as target speed signal) based on the head position signal; 6, a predetermined calculation based on the head speed signal and the target speed signal; (for example, addition) and outputs a control signal to control the following motors/it
7 is a power amplification circuit for amplifying the power of the control signal and outputting it as a motor drive signal; 8 is a power amplification circuit that is mechanically coupled to the magnetic head 2 and extends the magnetic head 2 in the radial direction on the magnetic disk 1 (not shown); This is a motor (drive source) that moves via an actuator.

Next, the operation will be explained. The magnetic head 2 is the magnetic disk 1
When moving in the radial direction on the magnetic disk 1, one of the plurality of magnetic disks 2 always maintains the positional information l1ll(
The head output signal) is read out, and the position signal generating circuit 3 receives and calculates the position information and outputs a head position signal. The speed signal generation circuit 4 calculates the head position signal and outputs a head speed signal, and the target speed generation circuit 5 outputs the head movement speed required at the head position given by the head position signal as a target speed signal. Output as . The operational amplifier circuit 6 adds and amplifies, for example, the target speed signal and the head speed signal with a fixed gain,
Outputs a control signal. The power amplifier circuit 7 amplifies the power of the control signal and supplies it to the motor 8 as a motor drive signal. Therefore, the motor 8 operates an actuator (not shown) to move the magnetic head 2 to a desired position on the magnetic disk 1.

FIG. 5 is a control block diagram showing the above-mentioned head positioning control system. In the figure, ■ is the target speed generation circuit 5
KA is the gain of the operational amplifier circuit 6, KP is the gain of the power amplifier circuit 7, KF is the force constant of the motor 8, and 1/M is the value of the movable part such as the actuator driven by the motor 8. The mass, 1/S is an integral function, ■H is the head speed #, and Kv is the speed detection sensitivity of this control system.

Therefore, the open-loop characteristic G of this control system, (
S) (Problem to be Solved by the Invention) As mentioned above, conventional magnetic disk drives perform head positioning by control as shown in FIG.
If a change in the force constant of , or a variation or change in the mass of the movable part driven by the motor 8 occurs, it becomes difficult to perform optimal head positioning control.

This invention was made to solve the above problems, and provides a magnetic disk device that can always perform optimal head positioning control even if the force constant of the motor for moving the magnetic head changes. The purpose is to obtain.

[Means to solve the problem]

The magnetic disk drive according to the present invention includes an acceleration signal generation circuit 9 that generates a movement acceleration signal of 7 to 1 to the magnetic field based on a head position signal output from the position signal generation circuit 3; The present invention is characterized in that it includes a gain control circuit 10 that outputs a gain control signal for changing the gain of the operational amplifier circuit 6 based on the outputted movement acceleration signal.

[Effect]

In this magnetic disk device, an acceleration signal generation circuit 9
generates a moving acceleration signal for the magnetic head 1 based on the head position signal output from the position signal generating circuit 3, and a gain control circuit 1o generates an operational amplifier circuit based on the moving acceleration signal output from the acceleration signal generating circuit 9. A gain control signal for changing the gain of 6 is output.

[Embodiments of the invention]

FIG. 1 is a block diagram showing the configuration of a head positioning control system in a magnetic disk device according to an embodiment of the present invention. In FIG. 1, components corresponding to those shown in FIG. 4 are designated by the same reference numerals, and their explanations will be omitted. In the figure, 9 is an acceleration signal generation circuit that generates a movement acceleration signal of the magnetic head 1 based on the head position signal output from the position signal generation circuit 3, and 10 is the movement acceleration output from the acceleration signal generation circuit 9. This is a gain control circuit that outputs a gain control signal for changing the gain of the operational amplifier circuit 6 based on the signal.

Next, the characteristic operation of this embodiment will be explained. The magnetic disk drive of this embodiment performs a several-degree seek operation at startup, that is, an operation in which the actuator is moved by the motor 8 so as to position the magnetic head 2 on the trunk of the magnetic disk l, and at this time the acceleration signal generation circuit 9 detects the moving acceleration of the magnetic head 2 at that time and outputs it as a variable acceleration signal. In this detection method, as shown in FIG.
The time it takes to arrive at a certain position X on the top (detect 1,
Calculate acceleration a. This acceleration a is X, =
can be determined by the relational expression (2). Based on the calculated acceleration a, the open loop characteristic G of the control system shown in FIG. 5 is determined. (
The gain control circuit 1 sets the gain KA such that S) is always constant.
The gain of the operational amplifier circuit 6 is changed to the optimum value KA by the gain control signal output from the gain control circuit 10. Therefore, even if the force constant KF, etc. of the motor 8 changes, the open loop characteristic GO(s) is controlled to be constant, so that optimal head positioning control can be performed.

In the above embodiment, the head movement acceleration was detected by detecting the time required to reach a certain position, but as shown in FIG. may be detected, and in this case, it is not affected by the inductance of the motor 8, and the detection accuracy is improved. The acceleration a in the case of FIG. 3 can be calculated by 1t -1°. However, 'It t!' of this equation (3)! represents the time required to reach the speed vI + vZ.

In this way, the magnetic disk device of the above embodiment estimates the characteristics of the mechanical section of the device by detecting the head movement acceleration, changes the gain of the operational amplifier circuit 6 to correct it, and controls the control system. Operates to optimize overall gain.

〔Effect of the invention〕

As described above, according to the present invention, there is provided an acceleration signal generating circuit that generates a moving acceleration signal of a magnetic head based on a head position signal outputted from a position signal generating circuit, and a moving acceleration signal outputted from this acceleration signal generating circuit. The configuration includes a gain control circuit that outputs a gain control signal to change the gain of the operational amplifier circuit based on the signal, so it is always optimal even if the force constant of the motor for moving the magnetic head changes. Further, it is possible to perform head positioning control with ease, and furthermore, it is possible to obtain the effect that adjustment of the control circuit system is not required for variations in characteristics of the mechanism section for moving the magnetic head.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a head positioning control system of a magnetic disk device according to an embodiment of the present invention, and FIG. 2 shows the relationship between head movement speed and time to explain the operation of this embodiment. 3 is a graph showing the relationship between head movement speed and time for explaining the operation of another embodiment. FIG. 4 is a block diagram showing the configuration of a head positioning control system of a conventional magnetic disk device. , FIG. 5 is a control block diagram of the head positioning control system. 1...Magnetic disc, 2...Magnetic head,
3. Old position signal generation circuit, 4... Speed signal generation circuit, 5... Target speed generation circuit, 6...
... operational amplifier circuit, 7 ... power amplifier circuit, 9 ... acceleration signal generation circuit, 10 ... gain control circuit. Agent Daikun Masu (2 idiots) Kaatsubutsu)! fIv5t. 8 Upper two fathers - t2- t+

Claims (1)

[Claims] a drive source such as a motor for moving the magnetic head in the radial direction on the magnetic disk; a position signal generation circuit that detects position information of the magnetic head with respect to the magnetic disk and outputs a head position signal; a speed signal generating circuit that generates a moving speed signal for the magnetic head based on a head position signal output from the signal generating circuit; a target speed generating circuit that generates a target moving speed signal based on the head position signal; In a magnetic disk drive comprising an operational amplifier circuit that performs a predetermined calculation based on a target movement speed signal and the movement speed signal and outputs a control signal for controlling the drive source, an output from the position signal generation circuit is provided. an acceleration signal generating circuit for generating a moving acceleration signal of the magnetic head based on the head position signal generated by the magnetic head; and an acceleration signal generating circuit for changing the gain of the operational amplifier circuit based on the moving acceleration signal output from the acceleration signal generating circuit. A magnetic disk device comprising a gain control circuit that outputs a gain control signal.