JPH1021571A - Learning control device for disk reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To satisfy the demand for high speed disk rotation control and to secure the stability of a control system by adding the output of a compensating signal of a specific component and the detecting output of an error signal, and controlling a pickup to follow a prescribed track and surface. SOLUTION: The circuit configuration of an error correcting signal generator 14 including a circuit for sampling an output signal from an error detector 15 at an output frequency from a frequency generator 13 for generating a frequency proportionate or a rotating speed of a spindle motor is operated. Then a tracking error signal and a focus error signal are generated by a preamplifier matrix 4 from various signals detected by a pickup 3. These signals are received by the error detector 15, and the their differences from target command values given to a target command input terminal 16 are detected by a subtractor 17, so as to control an actuator in the pickup 3 to carry out tracking and focusing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control apparatus for a disk reproducing apparatus using an optical pickup, which detects a focus tracking disk rotational speed error component synchronized with the disk rotation caused by eccentricity or surface deflection of a disk or the like. The present invention relates to a learning control device for a disk reproducing device that provides a high-performance servo control system by performing correction.

[0002]

2. Description of the Related Art There are many known examples of control devices for a disk reproducing apparatus using an optical pickup. For example, Japanese Patent Application Laid-Open No. 59-21723 discloses focus control.
7. Tracking control is disclosed in JP-A-58-14347.
2. For disk (spindle) rotation control,
8-56258 and the like. The overall system includes Ohm's "Compact Disc Reader" (authors: Heitaro Nakajima and Hiroshi Ogawa).

FIG. 10 shows an example of a control device of a basic conventional disk reproducing device. In the figure, 1 is a disk, 2
Is a spindle motor for rotating the disk, 3 is a pickup, 4 is a preamplifier matrix, 5 focus servo, 6 is a tracking servo, 7 is a thread servo, 8 is a data strobe, 9 is a synchronization separation circuit, 10 is a spindle servo, 11 Is a CD signal processing circuit, and 12 is D
2 shows a VD signal processing circuit.

The pickup 2 detects a signal from the disk, creates various signals by a preamplifier matrix 4, and supplies the signals to the next stage. The focus servo 5 processes the focus error signal obtained from the preamplifier matrix 4 to perform positioning of the disc 1 and the pickup 3 in the focus direction. The tracking servo 6 processes a tracking error signal obtained from the preamplifier matrix 4 to perform accurate positioning of the disk 1 and the pickup 3 in the tracking direction. The thread servo 7 processes a signal obtained from the tracking servo 6 to roughly align the disc 1 and the pickup 3 in the tracking direction.

The spindle servo 10 processes a signal obtained from the preamplifier matrix 4 into a data strobe 8 and a synchronizing signal obtained through a synchronizing separation circuit 9 to process a cycle error signal of the synchronizing signal.
To control the rotation speed of the. Further, according to the signal obtained by the data strobe 8, the CD signal processing circuit 11 or the DV signal
The D signal processing circuit 12 operates to provide an output signal.

Here, for example, characteristics of a focus control system are shown in FIG. The surface run-out specification of a disc is set, for example, at the limit value of the standard as shown in FIG. Therefore, the characteristics of the disk driver as shown in FIG. However, in recent years, disk drivers have been developed with X2, X4, X6 and X8 times the standard disk rotation speed for the purpose of reading data at high speed. If the disk is rotated by XN times at a high speed, the frequency direction of the limit value of the disk standard shown in FIG. On the other hand, the characteristics of the actuator section of the pickup 3 are as shown in FIG. 12, for example. That is, the high-frequency characteristic portion has a sub-resonance frequency, and it is difficult to configure a stable control system beyond this frequency band.

As the closest technique for solving such a problem, Nagasawa and Nakajima: "Tracking control of optical disk using observer", TV magazine, 43, 5 (198).
9).

[0008]

In such a situation, N
If an attempt is made to perform double-speed high-speed disk rotation control, a region where a necessary control band overlaps with the sub-resonance frequency is generated. For this reason, there has been a control limitation in increasing the speed.
Also, increasing the sub-resonance frequency has made the production of pickups more difficult. Therefore, an object of the present invention is to
It is an object of the present invention to provide a technique that satisfies such a demand for high-speed disk rotation control and also ensures the stability of a control system.

[0009]

To achieve the above object, the present invention is constituted by the following means. In a control device of a disk reproducing apparatus using an optical pickup, a rotation driving device for driving the rotation of the disk, a frequency generating device obtained according to the rotation speed of the disk, and the optical pickup from above the disk via the optical pickup An error signal detector for a tracking error signal, a focus error signal, and a disk rotation speed error signal obtained by the above method, and the rotation of the disk by the output signal of the frequency generator from the tracking error signal, the focus error signal, and the disk rotation speed error signal. A specific component detecting means for extracting a periodic component signal; a correction signal generating means for generating a correction signal of the specific component from an output of the specific component detecting means; an output of the correction signal generating means and the tracking error signal or focus error Signal or disk rotation speed error signal Tracking and focus control means for controlling the optical pickup to follow a predetermined track or surface on the disk by adding the output of the signal detector and the linear velocity of the optical pickup on the disk. Disk rotation speed control means for controlling the rotation speed to be constant.

Using these means, a disturbance control component (such as disk eccentricity and surface runout and a disturbance in linear velocity resulting therefrom) generated in synchronization with the rotation of the disk is improved by a learning control device, and a necessary disturbance suppression effect is obtained. Is what you get.

That is, the specific component detecting means for extracting the rotation period component signal of the disk from the various error signals, the eccentricity and surface deflection of the disk whose limit value is determined by the disk specification, and the linear velocity accompanying the disk eccentricity and surface deflection. A first-order frequency component to a N-th-order frequency component that causes disturbance or the like over one rotation of the disk are detected, and the first-order frequency component is corrected by a correction signal generating unit that generates a correction signal of the specific component based on the error component signal. By generating a correction signal of the frequency components from the first to the Nth order and adding this to the conventional servo control signal, a disturbance component (such as disk eccentricity, surface deflection, The learning control device can improve a linear velocity disturbance caused by the learning control device.

The operation of the specific component detecting means and the correction signal generating means is performed in synchronization with the output signal from the frequency generator obtained in accordance with the rotational speed of the disk, so that the rotational speed changes. In the configuration having a disk rotation speed control means for controlling the linear velocity of the optical pickup on the disk so as to be constant, the specific component detection means and the correction signal generation means can be more accurately and more reliably. It can work.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. First, an overall system to which the present invention is applied is shown in FIG. In this figure, the same circuits and functions as those in FIG. In the figure, 13 is a frequency generator for generating a frequency proportional to the rotation speed of the spindle motor, 14 is a focus servo 5 and a tracking servo 6
An error correction signal generator that detects each error signal from the spindle servo 10, extracts only an error signal component synchronized with the rotation of the spindle, and generates a signal for correcting the error signal component.

An error correction signal generator 1 which is a feature of the present invention.
Details of No. 4 are shown in FIGS. In the figure, 15 is an error detector, 16 is a target command input terminal, 17 is a subtractor, 18 is a sampling circuit, 19 is a primary component detector, 20 is an integrator, and 21 is a primary correction signal generator. , 22, and 23 are adders, 24 is a second order component detector, 25 is an integrator, 26 is a second order correction signal generator, 27 is an adder, 28 is an Nth order component detector, and 29 is an integrator. , 30 are an Nth correction signal generator,
31 indicates an adder.

FIG. 1 shows an embodiment in which the present invention is applied to a focus servo system and a tracking servo system for driving an actuator in the pickup 3. Error detector 1 in tracking servo 5 and focus servo 6
5, a target command input terminal 16, a subtractor 17, and the like. A pre-amplifier matrix 4 generates and outputs a tracking error signal and a focus error signal from various signals detected by the pickup 3. This is received by the error detector 15, the difference from the target command value given to the target command input terminal 16 is detected by the subtractor 17, and the pickup 3
The actuator inside is controlled for tracking and focusing.

Many of the purposes of the servo system here are to suppress disturbance components due to eccentricity and surface runout indicated by the limit values of the disc specifications shown in FIG. Therefore, it is considered that these components are generated in synchronization with the rotation of the disk, and it is possible to improve the generation of a correction signal by detecting the components in a learning manner. However, for CDs and DVDs, disk rotation control at a constant linear velocity called CLV (constant linear velocity) is performed. For this reason, since the disk rotation speed constantly changes, it is difficult to extract only these disk rotation components.

In the present invention, the output signal from the error detector 15 is converted into an error correction signal including a sampling circuit 18 by an output frequency from a frequency generator 13 for generating a frequency proportional to the rotation speed of the spindle motor. The signal generator 14 (first-order component detector 19, integrator 20, first-order correction signal generator 21 includes adders 22 and 23, second-order component detector 24, integrator 25, and second-order correction signal ), An adder 27, an Nth component detector 28, an integrator 29, an Nth correction signal creator 30, and an adder 31). ing.

The details of this operation will be described with reference to FIG.
In the output of the error detector 15, an error component based on one rotation cycle of the spindle (disk) as shown in the error signal in FIG. 3 is generated as a surface deflection or an eccentric component of the disk. This is sampled by an output signal from a frequency generator 13 that generates a frequency proportional to the rotation speed of the spindle motor as shown by the FG pulse in FIG. The signal is integrated, averaged, and based on this signal, the first correction signal generator 21 generates a phase inversion signal as shown in the correction signal of FIG. 3 for canceling this error signal. In the figure, 1
14 FG pulses are generated.

A storage means for storing the correction signal corresponding to the 14 shots is built in the first correction signal generator 21.
Similarly, the second-order,..., N-th order components can be corrected as harmonic components of the first-order error component shown in FIG. These processes are described in, for example, Japanese Patent Application Laid-Open No. 1-218380.
It is suitable for processing using a microcomputer as described in detail.

FIGS. 4 and 5 show one embodiment in which the microcomputer is used for the error correction signal generator 14. FIG. In the figure, the same circuits and functions as those shown in FIGS. 10, 1 and 2 are denoted by the same reference numerals. In the figure, 32 is an AD converter, 33 is an arithmetic unit, 34 is a ROM, 35 is a RAM, 36 is a DA converter, and 37 is a seek control input terminal. The error correction signal generator 14 composed of a microcomputer operates the AD converter 32 at the timing of the FG pulse from the frequency generator 13 as in FIG.
Is converted from an analog signal to a digital signal.

This digital signal is input to a computing unit 33, and the computing unit 33 detects the first to Nth components shown in FIG. Further, these data are stored in RAM3.
5 and integrated over several cycles with the spindle rotation period as a unit to improve the reliability (S / N). Based on these data, the first to Nth correction signals are created. These correction signals are sequentially stored in the RAM 3
5 is stored.

With this configuration, for example, when a seek control command for moving the pickup 3 across the track at a high speed and moving to the desired track is input to the seek control input terminal 37, this operation causes the operation shown in FIG. Since the period during which the tracking error signal is disturbed as shown in the seek control period of the tracking error signal can be predicted in advance, the component detectors 19, 24,.
By stopping the operation corresponding to 28 and generating an output from the RAM 35 which is already stored as a correction signal, it is possible to ensure high-speed and high-precision tracking performance even when pulling in a new track after seek control. I can do it.

As described above, the present invention provides circuit means suitable for realizing high-performance learning control for improving disk eccentricity of tracking control, disk surface deflection of focus control, and the like.

FIG. 6 shows an embodiment in which the present invention is applied to a spindle servo. In the figure, the same circuits and the same functions as those in FIGS. 1, 2, and 4 are denoted by the same reference numerals. In FIG. 1, a reproduction signal group obtained from the disk 1 via the pickup 3 with the rotational speed of the spindle motor 3 is converted into a digital signal via a preamplifier matrix 4 and a data strobe 8, and a synchronization detection circuit is obtained from the digital signal. 9, a specific synchronization signal is detected, and this cycle is measured by the error detector 15 to generate a spindle rotation speed error signal. The spindle servo 10 has an error detection circuit 15,
It comprises a target command input terminal 16 and a subtractor 17, and supplies this output to the spindle motor 2 via an adder 23.

On the other hand, the error correction signal generator 14 includes a sampling circuit 18, a first order component detector 19, an integrator 20,
The primary correction signal generator 21 includes adders 22 and 23,
Next component detector 24, integrator 25, second order correction signal generator 26, adder 27, Nth component detector 28, integrator 2
9, an N-th correction signal generator 30 and an adder 31. These operations are shown in FIG.
The same operation as in FIG. 3 is performed. This circuit is effective in basically removing the linear velocity at the position of the pickup 3 due to the eccentricity of the disk 1 and the like, in which the velocity unevenness (jitter) is generated in synchronization with the disk rotation cycle.

Next, FIGS. 8 and 9 show the effect of improving the servo control when the present invention is used. FIG. 8 shows the servo control characteristics required from the limit value of the disc specification. For example, in a mode in which a disc is rotated at eight times the standard (X8) and played, the limit value of the disc standard is naturally eight.
Requires twice the frequency band. Therefore, the characteristics of the disk driver require a control band indicated by a solid line in FIG. However, as shown in FIG. 12, the characteristic of the actuator of the pickup 3 has a sub-resonance frequency, so that it is difficult to secure a sufficient high-frequency band. That is, around the sub-resonance frequency, the phase rotation is severe, and a control band up to the vicinity of this frequency cannot be secured.

Therefore, by obtaining the servo improvement effect as shown in FIG. 9 according to the present invention, a stable control system can be obtained while covering the limit value of the disc specification. In the figure,
The meaning of the limit value of the disc standard is considered as an eccentric component synchronized with the rotation of the disk or a surface runout component synchronized with the rotation of the disk, and only these components are improved by the learning control system shown in the present invention. However, based on the idea that the bandwidth of the conventional feedback control system does not have to be secured up to eight times even for a disk rotation of eight times speed. As described above, with respect to the disk rotation frequency (including the Nth harmonic) component in the figure, a characteristic covering the limit value of the disk standard can be obtained, and strict specifications are not given to the actuator characteristic of the pickup 3. Further, it is possible to provide a servo control system capable of obtaining a higher-speed disk rotation reproduction technique.

[0028]

According to the present invention, the necessary control characteristics (improvement effect) of the focus servo system, the tracking servo system and the spindle servo system in the high-speed mode function of the disc reproducing apparatus can be improved by using a more expensive actuator having a high performance. A circuit that generates a learning correction signal in synchronization with the frequency that is proportional to the rotation speed of the spindle motor, which can follow the eccentricity of the disk and the runout component without the need for development, can be provided. It is possible to provide a servo control system of a disk reproducing apparatus that can cope with the mode.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a learning control device of a disc reproducing apparatus to which the present invention is applied.

FIG. 2 is a block diagram showing a detailed embodiment in which the present invention is applied to a focus servo system and a tracking servo system.

FIG. 3 is a waveform chart illustrating main operations in the block diagram of FIG. 2;

FIG. 4 is a block diagram showing another embodiment in which the present invention is applied to a focus servo system and a tracking servo system.

FIG. 5 is a waveform chart showing a characteristic operation in the block diagram of FIG. 4;

FIG. 6 is a block diagram showing a detailed embodiment in which the present invention is applied to a spindle servo system.

FIG. 7 is a waveform chart for explaining main operations in the block diagram of FIG. 6;

FIG. 8 is a characteristic diagram showing frequency components that must be followed by various servo systems of the high-speed disk reproducing device.

FIG. 9 is a characteristic diagram showing tracking characteristics of various servo systems when the present invention is applied.

FIG. 10 is a block diagram showing an example of a conventional disk reproducing apparatus.

FIG. 11 is a characteristic diagram showing frequency components that must be followed by various servos of the conventional standard speed disk reproducing device.

FIG. 12 is a characteristic diagram illustrating frequency characteristics of an actuator that drives a pickup.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Disc 2 Spindle motor which drives and rotates a disk 3 Pickup 4 Preamplifier matrix 5 Focus servo 6 Tracking servo 7 Thread servo 8 Data strobe 9 Synchronous separation circuit 10 Spindle servo 11 CD signal processing circuit 12 DVD signal processing circuit 13 Frequency generator 14 Error correction signal generator 15 Error detector 16 Target command input terminal 17 Subtractor 18 Sampling circuit 19 Primary component detector 20 Integrator 21 Primary correction signal generator 22, 23 Adder 24 Secondary component detector Reference Signs List 25 integrator 26 secondary correction signal generator 27 adder 28 Nth component detector 29 integrator 30 Nth correction signal generator 31 adder 32 AD converter 33 arithmetic unit 34 ROM 35 RAM 36 DA converter 37 seek control input terminal

Claims (12)

[Claims] 1. A control device for a disk reproducing apparatus using a pickup, comprising: a rotation drive device for driving rotation of the disk; a frequency generation device obtained in accordance with the rotation speed of the disk; A specific error detecting means for extracting a rotation cycle component signal of the disk in synchronization with the output of the frequency generator from the specific error detecting signal; Correction signal generating means for generating a correction signal of the specific component; adding an output of the correction signal generating means and an output of the tracking error signal detector to cause the optical pickup to follow a predetermined track on the disk And a tracking control means for controlling the disc reproduction apparatus to Learning control device. 2. The learning control device for a disk reproducing apparatus according to claim 1, wherein the operation of the specific component detecting means is performed at least during a seek control period in which a pickup is moved across a track at a high speed to a desired track. A learning control device for a disk reproducing device, wherein the output of the correction signal generating means is repeatedly and continuously output simultaneously with the stop. 3. A control device for a disk reproducing apparatus using a pickup, comprising: a rotation drive device for driving the rotation of the disk; a frequency generation device obtained in accordance with the rotation speed of the disk; A focus error signal detector, a specific component detecting means for extracting a rotation cycle component signal of the disk during the rainy season twice from the output of the frequency generator from the focus error signal, and the specific component detecting means And a correction signal generating means for generating a correction signal of the specific component from the output of the optical pickup, and adding the output of the correction signal generating means and the output of the focus error signal detector to move the optical pickup to a predetermined position in the disk. Learning control device for a disk reproducing apparatus, comprising: focus control means for performing control so as to follow the surface of the disk. . 4. The learning control device for a disk reproduction device according to claim 1, wherein the disk rotation speed is controlled so that a linear velocity of the pickup on the disk is constant. Learning control device for disc playback device. 5. A control device for a disk reproducing apparatus using a pickup, comprising: a rotation driving device for driving rotation of the disk; a frequency generating device obtained in accordance with the rotation speed of the disk; A disk rotation speed error signal detector obtained from a detection signal obtained through the disk drive, a specific component detection means for extracting a rotation period component signal of the disk from the disk rotation speed error signal by an output signal of the frequency generator, A correction signal generating means for generating a correction signal of the specific component from an output of the specific component detecting means; and adding the output of the correction signal generating means and the output of the disk rotation speed error signal detector to the Disk rotation speed control means for controlling the linear velocity of the pickup to be constant. Learning control device for disc playback device. 6. The learning control device for a disk reproducing device according to claim 1, wherein the specific component detecting means and the correction signal generating means process in synchronization with an output timing signal of the frequency generating device. A learning control device for a disk reproducing device. 7. The learning control device for a disk reproducing apparatus according to claim 1, wherein the correction signal generating means stores an output of the specific component detecting means for one rotation cycle of the disk. A learning control device for a disk reproducing device, comprising a memory means. 8. The learning control device for a disk reproducing apparatus according to claim 7, wherein said memory means has a memory capacity corresponding to at least the number of outputs of said frequency generator generated during one rotation cycle of said disk. A learning control device for a disk reproducing device, characterized by that: 9. A learning control device for a disk reproducing apparatus according to claim 7, wherein said memory means stores a correction signal corresponding to one rotation cycle of said disk, and holds a period during which disk rotation is stopped. A learning control device for a disk reproducing device, characterized by that: 10. A control device for a disk reproducing apparatus using a pickup, comprising: a rotation drive device for driving rotation of the disk; a frequency generation device obtained in accordance with the rotation speed of the disk; A tracking error signal detector obtained through the pickup from the disk, and a tracking error signal detector obtained through the pickup, synchronized with the output of the frequency generator from the tracking error signal and the focus error signal. Specific component detection means for extracting a rotation cycle component signal of the disk; tracking correction signal generation means and focus correction signal generation means for generating a correction signal of the specific component from an output of the specific component detection means; Output of generating means and detection of the tracking error signal Tracking control means for controlling the pickup so as to follow a predetermined track on the disk by adding the output of the focusing device, and the output of the focus correction signal generating means and the output of the focus error signal detector. Focus control means for controlling the pickup so as to follow a predetermined surface on the disc by adding the pickup to the disc. 11. A control device for a disk reproducing apparatus using a pickup, comprising: a rotation drive device for driving rotation of the disk; a frequency generation device obtained in accordance with the rotation speed of the disk; A tracking error signal detector obtained from the disk, a focus error signal detector obtained from the disk via the pickup, and a disk rotation speed error obtained from a detection signal obtained from the disk via the pickup. A signal detector, and a correction signal generating means for sampling the tracking error signal, the focus error signal, and the disk rotation speed error signal with a pulse synchronized with an output of the frequency generator, and generating each correction signal from the output. Of a disc reproducing apparatus characterized by comprising Learning control device. 12. A learning control device for a disk reproducing apparatus according to claim 10, wherein said correction signal generating means includes an AD converter, an arithmetic unit, a RAM unit, a ROM unit, and a D / A converter.
A learning control device for a disk reproducing device, comprising a digital operation processing circuit comprising an A converter.