JPS5960616A - Electronic servo-device - Google Patents

Abstract

PURPOSE:To suppress resonance vibrations in the vicinity of a zero position during the period of positioning by installing a blind sector intermitting circuit which intermits at a cycle shorter than the time required by a servomechanism for making a resonance vibration. CONSTITUTION:Information regarding the present position and an aimed position of a magnetic head, etc., is introduced to a difference counter 14 from the 1st and 2nd address registers 11 and 12 through an adder 13 and added to the 2nd adder 16 after it is converted 15 into an analog signal. The direction and speed of the magnetic head, etc., are detected by a converter 19 and a tachometer 20 and added to the adder 16 and a motor 18 is driven by the analog signal of the adder 16 after amplification 17. In this case, the signal from an oscillator 22, whose servo-clock 21 is reduced, is supplied to the amplifier 17 through a switching circuit 23 and a blind sector is intermitted, when the magnetic head, etc., approaches an aimed position and begins to reduce speed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a closed loop electronic servo system for positioning a device, such as a read/write head of a data disk drive, used for storing data in digital form on a magnetic storage device. In particular, the present invention provides an electronic servo device having a vibration prevention circuit for an electronic servo device having a VC configuration that cuts off the dead zone of an amplifier in order to prevent the rise of resonance vibration of an actuator when the zero position approaches. It is related to the device.

In general, in order to position an actuator to a target address with this type of electronic servo device, it is necessary to position the actuator in the vicinity of the target address and limit its vibration with the minimum response time of the necessary servo mechanism. Servo systems of the type used in this heel data disk device must operate accurately in positioning the read/write head to within a few microns of the desired address. Hence the head! ′! Since the A mechanism must be accurately and quickly positioned, the gain of the servo device must be made large enough to perform this operation.

FIG. 1 is a block diagram showing a conventional electronic servo device of this type, in which (11) is a first address register, (12) is a second address register, (13) is a first adder, (
14) is a difference counter, (15) is a digital-to-analog converter, (16) is a second adder, (17) is an amplifier,
(18) is the motor, (19)! -! , converter, (20)
is a tachometer, and the address register (
11) has information representing the current position of the magnetic head in order to control the positioning of the magnetic head;
The address register (12) has information representing the target position of the magnetic head, and both address registers (11)
(12) The signal generated by the first adder (
16) to a difference counter (14). Next, this difference counter (14) generates a signal representing the distance that the magnetic head should move in order to position it in the vicinity of the target address, and this difference count signal is converted into an analog signal by Digital-to-analog converter (15) VC led.

Next, this analog signal is guided to the motor (18) via a second adder (16) and an amplifier (17).
The analog signal supplied to this motor (18)K is converted by a signal generated by a converter (19). Therefore, this transducer (19) is able to change the direction of movement of the magnetic head;
The magnetic head is coupled to a second adder (16) via a tachometer (20) that detects the speed and changes the strength of the acceleration or deceleration signal when the magnetic head moves to the target position. has been done. In addition, the above-mentioned motor (1
The drive signal of 8) is shown in Fig. 3.The rK solid line (32)
The drive signal including the dead zone is shown by a broken line (63).

Conventional electronic servo devices of this type include, for example, v
However, any electronic servo device with broadband performance that usually requires a servo mechanism will always have a mechanical resonance point that causes instability in the servo mechanism. Because we generally have
Inevitably, vibrations tend to occur around the zero point of the servo device due to play in the mechanical device and its resonance characteristics. This vibration of the servo device can cause the magnetic head to deviate from the data track to an extent that may result in incorrect information being read.
Writing will occur.

In the past, as a means to deal with the vibration problem of this type of servo device, for example, the overall gain of the servo device was lowered, the resonance point was shifted so as not to affect the servo device, or the resonance point was completely changed. They were creating mechanisms that didn't exist before. However, such means are extremely expensive and often impossible to manufacture.

The present invention has been made with attention to this point, and it is an object of the present invention to provide an electronic servo device that positions a mechanical device using a dead zone in order to limit resonance vibration near the zero position of the servo mechanism. So, in short,
The present invention is characterized by an electronic servo device having a dead zone intermittent circuit that is intermittent at a period shorter than the time required for the resonance vibration of the servo mechanism during positioning of the magnetic head.

That is, although FIG. 2 shows one embodiment of the present invention, the same reference numerals refer to the same constituent members as in the conventional system described above (FIG. 1), and the explanation thereof will be omitted.

(21) is the servo clock, (22) + reducing factor oscillator,
(23) is an opening/closing circuit which is equipped with the above-mentioned dead band intermittent circuit for VC, J, and servo mechanism f, which oscillates 5 (
22) The oscillation signal generated by K is transmitted to the amplifier (17).
VC is supplied, and the dead zone is intermittently touched by this oscillation signal. Note that the oscillator (22)
The switching circuit (26) for the oscillation signal from the oscillation signal is operated depending on the output power VEoutJ (Fig. 3) detecting that the dead zone has been reached, and the operation of this intermittent dead zone is as follows. Since this is performed after the magnetic head position begins to decelerate K of the target address position, vibration of the servo device is prevented, and once the dead zone is reached, the magnetic head approaches the zero position.
It is ultimately set in the middle of the target address and the largest read signal is read from the data trunk.

As described above, the present invention has an excellent effect of using an intermittent dead zone intermittent circuit, which can effectively suppress resonance in the vicinity of the zero position of the servo mechanism.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing the entire conventional electronic servo device, Figure 2
The figure is a block diagram showing one embodiment of this invention, and FIG.
It is a characteristic diagram showing the positioning characteristics and the increase degree straight line in the case of "with dead zone" and "U with dead zone. In the drawing, (11) is the first address register, (12)
is the second address register, (16) is the first adder,
(14) is a difference counter, (15) is a digital-to-analog converter, (16) is a second adder, (17) is an amplifier, (18) is a motor, (19) is a converter, (20) is a ) is a tachometer, (21) is a servo clock, (22X is a step-down oscillator, and (23) is a switching circuit. In addition, the same reference numerals in the figure indicate the same or equivalent parts. Agent Shin Kuzuno - Figure 1 2 Figure 1 Otsu Figure 3 2 Masamasa

Claims (3)

[Claims] (1) In an actuator that moves an actuator in response to a target position signal - an oscillator with a reduced servo clock; 1. An electronic servo device characterized by: supplying an oscillation signal generated by the oscillation signal to an amplifier, and intermittent dead zones in the oscillation signal to suppress resonance vibration of an actuator. (2) The electronic servo device according to claim 1, further comprising: a dead zone intermittent circuit that is intermittent at a cycle shorter than the time required for the actuator to vibrate resonantly. (3) An electronic servo device according to claim 1, characterized in that a dead band intermittent circuit is formed by a servo clock, a step-down oscillator, a switching circuit, and K.