JPH09259449A - Positioning device for optical information recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a stable recording or reproducing operation without causing any focus displacement and track jumping even at the time of passing over an obstacle. SOLUTION: A 2nd calculating means 18 is composed of a disturbance observer for inferring disturbance such as surface wobbling and eccentricity, etc., and a 2nd control signal 27 is temporarily stored as the inferred disturbance, and a signal prior to one period, for example, is used as the control signal. On the other hand, a 1st control signal 26 from a 1st calculating means 17 is sent to an adder 21 after passing through an amplitude restricting means 32, and hence the control signal 27 is feedforwardly added to the 1st control signal 26 in this adder 21, and this result is outputted as a 3rd control signal 28. By sending this 3rd control signal 28 to a driver 23, an objective lens 8 can be positioned without causing any focus displacement and track jumping.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording / reproducing device used as an external storage means of a computer, and more particularly to a positioning device for an optical disk device.

[0002]

2. Description of the Related Art A conventional positioning device for an optical disk device is described in, for example, Japanese Patent Laid-Open No. 5-53014. In this conventional technique, the position error signal is passed through a low-pass filter to create a signal from which high frequency components have been removed, and is switched to the signal passed through the low-pass filter while an obstacle is passing. Further, in the conventional technique described in Japanese Patent Laid-Open No. 5-82660, the loop gain of the control system is made variable, and the loop gain is lowered while the obstacle is passing.

On the other hand, a conventional technique using the disturbance observer, the storage means and the low-pass filter is described in, for example, Japanese Patent Laid-Open No. 6-267211. In this conventional technique, a disturbance observer, a storage means and a low pass filter are used for a head positioning control system of a disk storage device. In the disk storage device, the tracks on the disk are arranged concentrically, and the disk is driven to rotate at a constant angular velocity. Therefore, when the head is tracing on each track, it synchronizes with the rotation that acts on the control system. The frequency component of the disturbance is constant on each track. Therefore, the storage means stores the output of the disturbance observer on a certain representative track, and cancels the disturbance acting on the control system on the other tracks by using the stored value. At this time, the output of the disturbance observer is also used in real time in order to cancel the disturbance that remains without being canceled by the stored value. After that, when the content of the storage means is updated when the disturbance becomes small, the stored value has a disturbance suppression capacity that is twice as large as that before the update, so by repeating the update operation,
It is designed to improve the ability to cancel disturbances. Further, the output of the disturbance observer stored in the storage means is configured such that high frequency components such as noise are removed by passing through the low pass filter.

[0004]

SUMMARY OF THE INVENTION In an optical disk device,
As shown in FIG. 2, when there are scratches (or stains, black spots, etc.) or dust or other obstacles on the optical disc 1, the return light from the optical disc 1 decreases while the light spot traces the obstacle. Alternatively, by missing, detection signals such as a focus error signal and a tracking error signal become indefinite. The influence is that the focus error signal and the tracking error signal suddenly become large in terms of waveform, and the frequency component is generally about 500 Hz, whereas the frequency component of 100 Hz or less such as surface wobbling and eccentricity is usually dominant. Therefore, frequency components of about several kHz become dominant.

Further, as shown in FIG. 3, there is a delay in detecting an obstacle. If control is performed based on such a focus error signal and tracking error signal, the light spot that is actually being traced will fluctuate, and focus down and unintended track jumps (below, track out To describe)
Occurs, and it takes a long time to record and reproduce a signal after passing an obstacle.

As a conventional method for coping with passage of an obstacle, a signal from which a high frequency component is removed is created by passing a position error signal through a low pass filter, and a signal passed through a low pass filter is switched during passage of an obstacle. There was also a method of changing the loop gain of the control system and lowering the loop gain while passing an obstacle.

However, with the above-described method in which the frequency components of about 500 Hz to several kHz appearing in the focus error signal and the tracking error signal due to the passage of the obstacle are not followed, the surface is not covered during the passage of the obstacle. Cannot follow runout and eccentricity. Further, since the delay in detecting the obstacle is not taken into consideration, it is impossible for the control system to deal with the obstacle until it is detected after the passage of the obstacle.

On the other hand, in the system using the disturbance observer, the storage means and the low pass filter in the magnetic disk device,
Since the optical disc device employs a storage method with a constant linear velocity, it is not possible to cope with the change in the surface runout and eccentricity frequency components depending on the reproduction velocity of the optical disc device and the reproduction position of the optical disc.

It is an object of the present invention to prevent focus-down and off-track occurrence even when passing an obstacle, and to shorten the time until the signal is recorded / reproduced after passing the obstacle so that stable recording / reproducing operation can be performed. It is an object of the present invention to provide a positioning device for an optical information recording / reproducing device which can be performed.

[0010]

In order to achieve the above object, a positioning device of an optical information recording / reproducing apparatus according to the present invention comprises a laser beam focused by an objective lens on a track on an optical information recording medium. In a positioning device of an optical information recording / reproducing device for recording / reproducing information by irradiating the optical spot of the optical disc under focusing control and tracking control, a position error signal and an information signal which are deviations of the optical spot from the track, etc. An amplifying means for generating an obstacle, an obstacle detecting means for detecting an obstacle existing at a trace position of the light spot on the optical information recording medium and outputting an obstacle detection signal, and the optical spot for the optical spot. The optical spot moving means for moving the information recording medium in the focus direction and the tracking direction, and the position error signal First calculation means for performing phase compensation calculation such as phase shift / lag compensation, state feedback compensation calculation including a state estimator, and outputting a first control signal as the calculation result; and the first calculation means. After that, the first correction means for correcting the first control signal, the position error signal and a predetermined third control signal are taken in, a disturbance estimation calculation by a disturbance observer is performed, and the first result is calculated as the calculation result. Second computing means for outputting the second control signal, adding means for adding the output of the first correcting means and the second control signal, and outputting the third control signal; Drive means for driving the light spot moving means in response to the control signal.

Further, the positioning device of the optical information recording / reproducing apparatus according to the present invention irradiates a track on the optical information recording medium with a light spot of a laser beam focused by an objective lens while focusing control and tracking control are performed. In the positioning device of the optical information recording / reproducing apparatus for recording / reproducing information by doing so, an amplifying means for generating a position error signal and an information signal which are deviations of the light spot from the track, and the optical information recording Obstacle detecting means for detecting an obstacle existing at a trace position of the light spot on the medium and outputting an obstacle detection signal, and moving the light spot in a focus direction and a tracking direction of the optical information recording medium. The light spot moving means and the position error signal are taken in, and position compensation such as phase lead / lag compensation is performed. Performs state feedback compensation operations including operations or state estimator, the first as a result of the calculation
First arithmetic means for outputting the control signal, first correction means for correcting the first control signal after the first arithmetic means, the position error signal and a predetermined third control. The second control signal after the second calculation means for fetching the signal, performing the disturbance estimation calculation by the disturbance observer, and outputting the second control signal as the calculation result. Second correcting means for correcting, an adding means for adding the output of the first correcting means and an output of the second correcting means to output the third control signal, and the third control signal Drive means for driving the light spot moving means.

Further, the positioning device of the optical information recording / reproducing apparatus according to the present invention takes in the second control signal,
After the cycle detecting means for detecting the cycle of the second control signal and outputting the cycle signal, and the second computing means or the second correcting means, the second control signal or the second The output of the correction means is stored according to the rotational position of the optical information recording medium by the periodic signal, the presence or absence of an obstacle in storage is determined by the obstacle detection signal, and the optical signal is output by the periodic signal. It is characterized in that it further comprises storage means for outputting the previously stored signal corresponding to the rotational position of the information recording medium.

Further, in the positioning device of the optical information recording / reproducing apparatus according to the present invention, the storage interval of the second control signal or the output of the second correcting means to the storage means is determined by the first computing means. It is characterized in that it is longer than the calculation sampling interval of.

Further, the positioning device of the optical information recording / reproducing apparatus according to the present invention is characterized by comprising an interpolation means for interpolating the signal stored in the storage means when the signal is output.

Further, the positioning device of the optical information recording / reproducing apparatus according to the present invention comprises the second control signal and the second control signal.
Of the output of the correction means or the output of the storage means or the output of the interpolation means, and when the obstacle detection signal is not generated, the second control signal is selected, and the obstacle detection signal is When it is occurring, any one of the output of the second correction means, the output of the storage means or the output of the interpolation means is selected, and the switching means for outputting the selected signal; and the first control A signal or an output of the first correcting unit and an output of the switching unit are added to each other, and an adding unit that outputs the third control signal is provided.

Further, in the positioning device of the optical information recording / reproducing apparatus according to the present invention, when the first correction means fetches the first control signal exceeds a set value,
The amplitude limiting means outputs the set value as the control signal.

Further, in the positioning device of the optical information recording / reproducing apparatus according to the present invention, the first correcting means is the first removing means for removing the high frequency component of the first control signal taken in. Is characterized by.

Further, in the positioning device of the optical information recording / reproducing apparatus according to the present invention, the second correcting means is the second removing means for removing the high frequency component of the second control signal taken in. Is characterized by.

Further, the positioning device of the optical information recording / reproducing apparatus according to the present invention is the third removing means for removing the high frequency component of the second control signal taken in by the second correcting means, In the third removing means, the frequency band for removing the high frequency component of the captured second control signal changes according to the rotation speed of the optical information recording medium.

Further, in the positioning device of the optical information recording / reproducing apparatus according to the present invention, the second correcting means removes the high frequency component of the second control signal taken in by the second correcting means or the third removing means. And the holding means for holding either the output of the second removing means or the output of the third removing means while the obstacle detection signal is generated. It is characterized by

Further, the positioning device of the optical information recording / reproducing apparatus according to the present invention irradiates a track on the optical information recording medium with a light spot of a laser beam focused by an objective lens while performing focusing control and tracking control. In the positioning device of the optical information recording / reproducing apparatus for recording / reproducing information by doing so, an amplifying means for generating a position error signal and an information signal which are deviations of the light spot from the track, and the optical information recording Obstacle detecting means for detecting an obstacle existing at a trace position of the light spot on the medium and outputting an obstacle detection signal, and moving the light spot in a focus direction and a tracking direction of the optical information recording medium. The light spot moving means and the position error signal are taken in, and position compensation such as phase lead / lag compensation is performed. Performs state feedback compensation operations including operations or state estimator, the first as a result of the calculation
Of the position error signal and a predetermined third control signal, performs disturbance estimation calculation by a disturbance observer, and outputs the second calculation result as the second calculation result.
Second calculation means for outputting the control signal of the above, and after the second calculation means, the second control signal is fetched, the high frequency component of the fetched second control signal is removed, and the removal is performed. The frequency band of the third information removing means whose frequency band changes in accordance with the number of rotations of the optical information recording medium, the first control signal and the output of the third removing means are added, and the third removing means is added. And an driving means for driving the light spot moving means in response to the third control signal.

Further, the positioning device of the optical information recording / reproducing apparatus according to the present invention irradiates the track on the optical information recording medium with the light spot of the laser beam focused by the objective lens while performing focusing control and tracking control. In the positioning device of the optical information recording / reproducing apparatus for recording / reproducing information by doing so, an amplifying means for generating a position error signal and an information signal which are deviations of the light spot from the track, and the optical information recording Obstacle detecting means for detecting an obstacle existing at a trace position of the light spot on the medium and outputting an obstacle detection signal, and moving the light spot in a focus direction and a tracking direction of the optical information recording medium. The light spot moving means and the position error signal are taken in, and position compensation such as phase lead / lag compensation is performed. Performs state feedback compensation operations including operations or state estimator, the first as a result of the calculation
Of the position error signal and a predetermined third control signal, performs disturbance estimation calculation by a disturbance observer, and outputs the second calculation result as the second calculation result.
Second calculation means for outputting the control signal, cycle detection means for fetching the second control signal, detecting the cycle of the second control signal, and outputting a cycle signal, and the second calculation means. After that, the second control signal is stored corresponding to the rotational position of the optical information recording medium by the periodic signal, and the presence or absence of the stored obstacle is determined by the obstacle detection signal,
Storage means for outputting a signal previously stored corresponding to the rotation position of the optical information recording medium by the periodic signal, and the third control by adding the first control signal and the output of the storage means. It is characterized by comprising an adding means for outputting a signal and a driving means for driving the light spot moving means by the third control signal.

Further, the positioning device of the optical information recording / reproducing apparatus according to the present invention irradiates the track on the optical information recording medium with the light spot of the laser beam focused by the objective lens while performing focusing control and tracking control. In the positioning device of the optical information recording / reproducing apparatus for recording / reproducing information by doing so, an amplifying means for generating a position error signal and an information signal which are deviations of the light spot from the track, and the optical information recording Obstacle detecting means for detecting an obstacle existing at a trace position of the light spot on the medium and outputting an obstacle detection signal, and moving the light spot in a focus direction and a tracking direction of the optical information recording medium. The light spot moving means and the position error signal are taken in, and position compensation such as phase lead / lag compensation is performed. Performs state feedback compensation operations including operations or state estimator, the first as a result of the calculation
Of the position error signal and a predetermined third control signal, performs disturbance estimation calculation by a disturbance observer, and outputs the second calculation result as the second calculation result.
Second calculation means for outputting the control signal, cycle detection means for fetching the second control signal, detecting the cycle of the second control signal, and outputting a cycle signal, and the second calculation means. After that, the second control signal is fetched, the high frequency component of the fetched second control signal is removed, and the frequency band to be removed changes in accordance with the rotation speed of the optical information recording medium. And a third removing means for storing the output of the third removing means corresponding to the rotational position of the optical information recording medium by the periodic signal after the third removing means. Judgment of the presence of obstacles in memory by the detection signal,
Storage means for outputting a signal previously stored corresponding to the rotation position of the optical information recording medium by the periodic signal, and the third control by adding the first control signal and the output of the storage means. It is characterized by comprising an adding means for outputting a signal and a driving means for driving the light spot moving means by the third control signal.

Further, in the positioning device of the optical information recording / reproducing apparatus according to the present invention, the storage interval of the second control signal or the output of the third removing means to the storage means is determined by the first computing means. It is characterized in that it is longer than the calculation sampling interval of.

Further, the positioning device of the optical information recording / reproducing apparatus according to the present invention is characterized by comprising an interpolating means for interpolating the signal stored in the storing means.

Further, the positioning device of the optical information recording / reproducing apparatus according to the present invention comprises the second control signal and the third control signal.
Of the output of the removing means, the output of the storage means, or the output of the interpolating means, and when the obstacle detection signal is not generated, the second control signal is selected, and the obstacle detection signal is When it is occurring, the output of the third removing means, the output of the storage means, or the output of the interpolating means is selected, and the switching means for outputting the selected signal; and the first control And a summing means for adding the signal and the output of the switching means to output the third control signal.

Further, in the positioning device of the optical information recording / reproducing apparatus according to the present invention, the first control signal is provided after the first computing means while the obstacle detecting means is detecting an obstacle. Is provided with a third correction means for making zero.

Further, in the positioning device of the optical information recording / reproducing apparatus according to the present invention, the setting value of the amplitude limiting means is such that the first period after the focusing control or the tracking control is started and the second period after that. And are characterized in that the magnitudes of the set values are different.

Further, in the positioning device of the optical information recording / reproducing apparatus according to the present invention, the setting value of the amplitude limiting means is equal to or more than the operation range of the first control signal when the obstacle is not present, It is characterized by being less than twice.

Further, in the positioning device of the optical information recording / reproducing apparatus according to the present invention, the first control signal taken in by the first removing means, the second removing means and the third removing means, or The frequency at which the high frequency component of the second control signal starts to be removed is equal to or higher than the maximum rotation frequency of the optical information recording rotary medium and is equal to or lower than 10 times the maximum rotation frequency.

Further, the positioning device of the optical information recording / reproducing apparatus according to the present invention comprises the first computing means, the second computing means, the cycle detecting means, the storing means, the adding means, the switching means, The first correcting means, the second correcting means, and the third correcting means are integrated into one IC.
It is characterized by being composed of a chip.

Next, the operation of the present invention will be described. The second computing means in the positioning device of the optical information recording / reproducing apparatus of the present invention is a disturbance observer for estimating a disturbance such as surface wobbling and eccentricity. By adding the second control signal, which is the estimated disturbance, to the first control signal in a feed-forward manner, it is possible to follow the disturbance such as surface wobbling and eccentricity with high accuracy. In addition, the second control signal is stored in the storage means and the signal of the previous cycle is used, or
The control signal of is passed through the second removing means or the third removing means, and the signal from which the high frequency component is removed is used. In addition, the first control signal is passed through the amplitude limiting means, Since the first control signal is prevented from suddenly increasing during passage of the obstacle, it is not affected by the passage of the obstacle. For this reason, it is possible to prevent focus-down and off-track, and also shorten the time until recording / reproduction of a signal after passing an obstacle, and perform stable recording / reproduction operation.

[0033]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is a block diagram of focusing control means of an optical disk device according to a first embodiment of the present invention. Reference numeral 1 denotes an optical disc, in which tracks 2 are spirally formed in the circumferential direction. Reference numeral 3 denotes a disk motor, which rotationally drives the optical disk 1 chucked on the upper surface. A pickup 4 is a semiconductor laser 6 that emits a laser beam 5, and a track 2 that focuses the laser beam 5.
An objective lens 8 that forms a light spot 7 on it, a sensor 10 that detects a position error signal and an information signal of the light spot 7 from the reflected light 9 from the track 2, and a focus actuator 11 that drives the objective lens 8 in the focus direction. And a tracking actuator 12 that drives in the tracking direction, a sled 13 that accommodates and moves the above components, and a linear actuator 14 that drives the sled 13 in the radial direction of the optical disc 1 to move the light spot 7 between tracks 2. Consists of.

Further, 15 is an amplification means, 16 is an AD converter, 17 is a first calculation means, 18 is a second calculation means, 1
Reference numeral 9 is a first storage means, 20 is a central processing means, 21 is an adder, 22 is a DA converter, 23 is a driver, 24 is an IC chip, 25 is a focus error signal, 26 is a first control signal, and 27 is Second control signal, 28 is third control signal, 2
Reference numeral 9 is an information signal, 30 is an obstacle detecting means, 31 is an obstacle detecting signal, and 32 is an amplitude limiting means.

According to the above structure, the amplifying means 15 performs predetermined signal processing on the detection output of the pickup 4 to generate the focus error signal 25, the tracking error signal (not shown) and the information signal 29. The focus error signal 25 is input to the AD converter 16, and the information signal 29 is input to the obstacle detecting means 30. The obstacle detecting means 30 takes in the information signal 29 and outputs the information signal 2
The presence or absence of an obstacle is detected by comparing the level of 9 with the set level, and the obstacle detection signal 31 is output. This obstacle detection signal 31 is input to the central processing means 20.

In the first arithmetic means 17, the focus error signal 25 is converted into a digital signal by the AD converter 16 and taken in, and software is read from the first storage means 19 in accordance with a command from the central processing means 20, A phase compensation calculation such as phase advance / delay compensation or a state feedback compensation calculation including a state estimator is performed, and the calculation result is output as a first control signal 26. The first control signal 26 is input to the amplitude limiting means 32. Amplitude limiting means 32
Then, the first control signal 26 is fetched, and the central processing means 2
In response to a command of 0, the amplitude setting value is read from the first storage means 19, and the amplitude value of the first control signal 26 is limited by comparing the amplitude value of the first control signal 26 with the setting amplitude value. . The output of the amplitude limiting means 32 is input to the adder 21.

On the other hand, in the second calculating means 18, the focus error signal 25 is converted into a digital signal by the AD converter 16 and taken in, and the third control signal 28 is taken in, and by the instruction of the central processing means 20, Software is read from the first storage means 19, a disturbance observer composed of a state estimator is calculated, and the calculation result is output as a second control signal 27. The second control signal 27 is input to the adder 21.

The adder 21 takes in the output of the amplitude limiting means 32 and the second control signal 27, adds them, and then outputs them as the third control signal 28. This third control signal 28
Is input to the second computing means 18 and the DA converter 22.
The driver 23 sends the third control signal 28 to the DA converter 2
In step 2, the signal is converted into an analog signal and is taken in, and the focus actuator 11 drives the objective lens 8 in the focus direction to position the track 2 of the optical disc 1 so as to be within the depth of focus of the objective lens 8.

Here, the first calculation means 17 will be described in detail. The first calculation means 17 can be realized by state feedback compensation including a state estimator, but in the present embodiment, phase lead / lag compensation is used. The discrete-time transfer function of the first calculation means 17 at this time is expressed by the following equation.

[0040]

[Equation 1]

However, z ~ ¹ is one sample delay, a ₂ , a
₃ , b ₁ , b ₂ and b ₃ are coefficients that determine the frequency characteristic of the first calculating means 17, and K _C is a loop gain of the first calculating means 17.

The first calculation means 17 takes in the focus error signal 25 at every sampling period T _S and outputs the first control signal 26 as a digital compensation calculation result. Hereinafter, the focus error signal 25 is represented by e (k),
The first control signal 26 is represented by U ₁ (k). Where k is the time index of each digital sample. From the focus error signal e (k) to the first control signal U ₁ (k)
The output equation up to

[0043]

[Equation 2]

Although the first control signal U ₁ (k) is obtained by the equation 2, the following equation of state is calculated in order to obtain U ₁ (k) also in the next sample.

[0045]

(Equation 3)

Next, the second calculating means 18 will be described in detail. In the second calculation means 18, the focus error signal 25 and the third control signal 28 are provided every sampling period T _S.
And are output, and the second control signal 27 is output as the digital compensation calculation result. Hereinafter, the second control signal 27 is changed to U
₂ (k) and the third control signal 28 is represented by U ₃ (k). From the focus error signal e (k) to the second control signal U
The output equation for obtaining ₂ (k) is shown in Equation 4.

[0047]

(Equation 4)

However, H is expressed by Equation 5, and is a gain for canceling the disturbance in the steady state. Also,
K ₁ is a gain obtained by multiplying the DC gain of the driver 23 by the DC gain of the focus actuator 11, K ₂ is a gain of the amplification means 15, and L ₂ is a feedback gain of the second calculation means 18.

[0049]

(Equation 5)

The following equation of state is calculated for the next sample.

[0051]

(Equation 6)

Here, M is the mass of the movable part of the actuator, and L ₁ and L ₂ are feedback gains that determine the convergence speed of the disturbance estimation.

Next, the calculation procedure described above is applied to the first operation in FIG.
This will be described using a flowchart showing an example of the calculation procedure of the calculation means 17 and the second calculation means 18. First, the focus error signal 25 is fetched from the AD converter 16, and the third control signal 28 is also fetched, and e (k)
And U ₃ (k) (100 in FIG. 4). Next, the output equations (2) and (4) are calculated (101 in FIG. 4), and the first control signal U ₁ (k) and the second control signal U ₂ (k) are output (102 in FIG. 4). . Finally, for the next sample, the equations of state 3 and 6 are calculated (103 in FIG. 4).

Next, the obstacle detecting means 30 will be described with reference to FIG.
This will be described with reference to the waveform chart showing the waveform of each signal when the obstacle passes. When the optical disc 1 having an obstacle is reproduced, the information signal 29 becomes as shown in FIG. The obstacle detecting means 30 detects the region where this signal is missing by comparing with the set level, and outputs the obstacle detection signal 31 as shown in FIG. 3C during the period in which the obstacle is detected. . At this time, a detection delay occurs in the obstacle detection signal 31, as shown in FIG. Any other method may be used as the obstacle detecting means 30, but the basis thereof is to compare an appropriate signal with a set level, and a detection delay will always occur.

Next, the amplitude limiting means 32 will be described with reference to the characteristic diagram showing the input / output characteristics of the amplitude limiting means 32 in FIG. The horizontal axis represents the input of the amplitude limiting means 32, and the vertical axis represents the output of the amplitude limiting means 32. When the amplitude value of the first control signal 26 exceeds the set amplitude value, the amplitude value of the first control signal 26 is limited to the set amplitude value. The set amplitude value is determined by the amplitude value or the like of the first control signal 26 when there is no obstacle.

Next, the effect of this embodiment will be described. FIG. 6 is a frequency characteristic diagram from a disturbance added to the focus error signal 25 to a signal after the disturbance is added. The horizontal axis represents frequency and the vertical axis represents the disturbance suppression amount of the control system. In the figure, the smaller the value, the higher the disturbance suppression characteristic. The broken line is the characteristic when the second computing means 18 corresponding to the prior art is not provided, and the solid line is the characteristic when the second computing means 18 according to the present embodiment is provided.

Second computing means 18 which is a disturbance observer
Has a function of extracting a disturbance having a frequency component within the estimated band of the disturbance observer and adding it to the first control signal 26 to remove the influence of the disturbance. More specifically, the second computing means 18, which is a disturbance observer, performs feedforward compensation, and the second control signal 27, which is a feedforward compensation signal that estimates the disturbance applied to the control system, causes disturbance such as surface wobbling. The light spot 7 is made to follow the track 2 which is fluctuating due to. In addition, the first computing means 17, which is the main compensator, performs feedback compensation on the error that could not be compensated by the feedforward compensation.

As described above, the positioning apparatus according to the present embodiment has a configuration in which the control system includes the two compensation methods of the feedforward compensation portion and the feedback compensation portion. Therefore, as shown in the frequency characteristic of FIG.
As compared with the conventional technique having only the feedback compensation part, it is possible to obtain high disturbance suppression characteristics in the low frequency region and suppress the disturbance such as surface wobbling as compared with the related art.

If there is an obstacle on the optical disc 1,
While the light spot 7 is tracing on this, the focus error signal 25 is indefinite. In the prior art, since only feedback compensation is performed, the position of the light spot 7 cannot be controlled on the track 2 which is fluctuating due to disturbance such as surface wobbling while the obstacle is passing. On the other hand, in the positioning device according to the present embodiment, the feedback compensation part and the feedforward compensation part are included, so during the passage of the obstacle, the open loop control of the feedforward compensation causes
Positioning control of the light spot 7 can be performed on the track 2 that is fluctuating due to disturbance such as surface wobbling, and focus down and track deviation do not occur. Further, since the light spot 7 follows the track 2 which is changing due to disturbance such as surface wobbling even while passing the obstacle, the fluctuation due to the transient characteristic of the control system after passing the obstacle can be reduced, and the recording / reproducing of the signal can be performed. You can shorten the time until.

Further, while the obstacle is passing, the first control signal 26 is affected by the indefinite focus error signal 25.
Has a pulse shape as shown in FIG. When this first control signal 26 is applied to the focus actuator 11,
May cause focus down. In the prior art using the disturbance observer, the storage means and the low-pass filter, the first control signal 26 is used as it is, and therefore the pulsed first control signal 26 is added to the focus actuator 11. , Can cause focus down. On the other hand, in the positioning device according to the present embodiment, the amplitude limiting means 32
As a result, the first control signal 26 is prevented from being pulsed, and the first control signal 26 becomes as shown in FIG. 7 (e). Especially when there is an obstacle detection delay, it is possible to prevent the pulse-shaped first control signal 26 from unconditionally being applied to the focus actuator 11 by the time the obstacle detection signal 31 is detected. it can.
As a result, while the obstacle is passing, the open spot control of the feedforward compensation by the disturbance observer can perform the positioning control of the light spot 7 on the track 2 which is fluctuated by the disturbance such as surface wobbling, and the focus down and the track deviation do not occur. .

Further, in the positioning device as described above, the same effect can be obtained by adopting the same configuration also in the case of the tracking control means. Furthermore, D
It goes without saying that the same effect can be obtained also in the case of a VD (digital video disk) device, a magnetic disk device or the like by adopting the same configuration.

(Second Embodiment) Hereinafter, a second embodiment of the present invention will be described.
Embodiments will be described with reference to the drawings. FIG.
It is a block diagram of the focusing control means of the optical disk device by the 2nd Embodiment of this invention. The feature of this embodiment is that the amplitude limiting means 3 of FIG. 1 shown in the first embodiment is used.
The second removing means 33 is provided instead of the second removing means 33.

According to the configuration shown in FIG. 8, the first removing means 33 takes in the first control signal 26 and
In response to a command from the central processing means 20, the software is read from the first storage means 19, low-pass filter calculation of the first or higher order is performed, and the calculation result is output. The output of the first removing means 33 is input to the adder 21.

Here, the first removing means 33 will be described in detail. The first removing means 33 is executed by a low-pass filter of a first order or higher order, but in the present embodiment, a first-order low-pass filter is used. The discrete-time transfer function of the first removing means 33 at this time is expressed by Equation 7.

[0065]

(Equation 7)

However, a _L2 , b _L1 and b _L2 are coefficients that determine the frequency characteristic of the first removing means 33.

The first removing means 33 fetches the first control signal 26 at every sampling period T _S , performs a digital operation, and outputs the operation result. Hereinafter, the output of the first removing means 33 is represented by U _1L (k). The output equation from the first control signal U ₁ (k) to the output U _1L (k) of the first removing means 33 is shown in Equation 8.

[0068]

(Equation 8)

The output U _1L of the first removing means 33 is calculated by the equation 8.
(K) is obtained, but U _1L (k) is also obtained in the next sample.
To obtain, the following equation of state is calculated.

[0070]

[Equation 9]

The calculation procedure of the first removing means 33 described above will be described with reference to the flowchart of FIG. First, the first control signal 26 is fetched and input to U ₁ (k) (200 in FIG. 9). Next, the output equation number 8 is calculated (201 in FIG. 9), and the output U of the first removing means 33 is calculated.
_1L (k) is output (202 in FIG. 9). Finally, the state equation (9) is calculated for the next sample.

Next, the effect of the present embodiment will be described. The positioning device according to the present embodiment is configured to include two compensation methods, a feedforward compensation part and a feedback compensation part, inside the control system. For this reason,
As shown in the frequency characteristic of FIG. 6, it is possible to obtain a high disturbance suppression characteristic in the low frequency region and suppress disturbance such as surface wobbling as compared with the related art, which has only a feedback compensation portion.

Further, since the positioning device according to the present embodiment comprises the feedback compensating part and the feedforward compensating part, the open spot control of the feedforward compensating causes the light spot 7 to be deflected while the obstacle is passing. Positioning control can be performed on the track 2 that is fluctuating due to disturbance, and focus down and track deviation do not occur. Furthermore, since the light spot 7 follows the track 2 which is changing due to disturbance such as surface wobbling while the obstacle is passing,
The fluctuation due to the transient characteristics of the control system after passing through the obstacle can be reduced, and the time until recording / reproducing of the signal can be shortened.

Further, as described above, during the passage of the obstacle, the first control signal 26 becomes pulsed as shown in FIG. 7C due to the influence of the indefinite focus error signal 25. When this first control signal 26 is applied to the focus actuator 11, there is a possibility that focus down will occur. On the other hand, in the positioning device according to the present embodiment, the pulse shape waveform is removed from the first control signal 26 by the first removing means 33, as shown in FIG.
(G). As a result, the open-loop control of the feedforward compensation by the disturbance observer can control the positioning of the light spot 7 on the track 2 which is fluctuated by the disturbance such as surface wobbling, and the focus down and the track deviation do not occur.

Further, in the positioning device as described above, the same effect can be obtained by adopting the same structure also in the case of the tracking control means. Furthermore, D
It goes without saying that the same effect can be obtained also in the case of a VD (digital video disk) device, a magnetic disk device or the like by adopting the same configuration.

(Third Embodiment) The third embodiment of the present invention will be described below.
Embodiments will be described with reference to the drawings. FIG.
FIG. 9 is a configuration diagram of focusing control means of an optical disc device according to a third embodiment of the present invention. The feature of the present embodiment is that the configuration of FIG. 1 shown in the first embodiment is
That is, the second removing means 34 is added.

According to the configuration shown in FIG. 10, the second removing means 34 fetches the second control signal 27 and, at the command of the central processing means 20, receives the first storage means 1.
The software is read from 9, the low-pass filter operation of the first order or higher order is performed, and the operation result is output. The output of the second removing means 34 is input to the adder 21. Here, since the configuration of the second removing means 34 is the same as that of the above-mentioned first removing means 33, the description thereof will be omitted.

Next, the effect of this embodiment will be described. The positioning device according to the present embodiment is configured to include two compensation methods, a feedforward compensation part and a feedback compensation part, inside the control system. For this reason,
As shown in the frequency characteristic of FIG. 6, it is possible to obtain a high disturbance suppression characteristic in the low frequency region and suppress disturbance such as surface wobbling as compared with the related art, which has only a feedback compensation portion.

Further, in the positioning device according to the present embodiment, the amplitude control means 32 prevents the first control signal 26 from being pulsed, and the first control signal 26
Is as shown in FIG. Especially when there is an obstacle detection delay, it is possible to prevent the pulse-shaped first control signal 26 from unconditionally being applied to the focus actuator 11 by the time the obstacle detection signal 31 is detected. it can. As a result, while the obstacle is passing, the open spot control of the feedforward compensation by the disturbance observer can perform the positioning control of the light spot 7 on the track 2 which is fluctuated by the disturbance such as surface wobbling, and the focus down and the track deviation do not occur. .

Further, normally, the frequency component of disturbance such as surface wobbling is 100 Hz or less, and the frequency component appearing in the focus error signal 25 due to passage of an obstacle is 500 Hz to several k.
Hz or less. Focusing on this point, the positioning apparatus according to the present embodiment creates a signal from the second control signal 27, in which the second removing means 34 removes the frequency component that appears due to the passage of the obstacle. By the open-loop control of the feedforward compensation using the signal from which the frequency component is removed, the light spot 7 can be positioned and controlled on the track 2 which is fluctuating due to the disturbance such as the surface wobbling, and the focus down and the track deviation do not occur. Further, since the light spot 7 follows the track 2 which is changing due to disturbance such as surface wobbling even while passing the obstacle, the fluctuation due to the transient characteristic of the control system after passing the obstacle can be reduced, and the recording / reproducing of the signal can be performed. You can shorten the time until.

Further, in the positioning device as described above, the same effect can be obtained by using the first removing means 33 instead of the amplitude limiting means 32. Further, also in the case of the tracking control means, the same effect can be obtained by adopting the same configuration. Furthermore, DVD
It goes without saying that the same effect can be obtained by using the same configuration in the case of a (digital video disk) device, a magnetic disk device, or the like.

(Fourth Embodiment) The fourth embodiment of the present invention will be described below.
Embodiments will be described with reference to the drawings. FIG.
FIG. 9 is a configuration diagram of focusing control means of an optical disc device according to a fourth embodiment of the present invention. The feature of this embodiment is that a third removing means 35 and a cycle detecting means 36 are added to the configuration of FIG. 1 shown in the first embodiment. In FIG. 11, reference numeral 37 is a periodic signal output from the period detecting means 36 to the central processing means 20.

According to the configuration of FIG. 11, the third removing means 3
In No. 5, the second control signal 27 is fetched, the software is read from the first storage unit 19 in accordance with the instruction of the central processing unit 20, and the low-pass filter calculation of the first or higher order is performed, and the calculation result is obtained. Is output. The output of the third removing means 35 is input to the adder 21. The cycle detecting means 36 takes in the second control signal 27, performs processing such as polarity determination, and outputs a pulse corresponding to the cycle as a cycle signal 37. The periodic signal 37 is input to the central processing means 20. Here, the third removing means 3
The configuration of No. 5 is the same as that of the above-mentioned first removing means 33, and therefore its explanation is omitted.

Next, the operation of the cycle detecting means 36 will be described with reference to the waveform chart of FIG. Second control signal 27
Is a signal in which the surface wobbling is estimated, and therefore vibrates in the cycle of the surface wobbling as shown in FIG. Periodic signal 37
Is determined by determining the polarity (FIG. 12B), taking the difference between the samples (FIG. 12C), and selecting either positive or negative value. In this embodiment, a positive value is selected (FIG. 12 (d)).

Further, the third removing means 35 sets a coefficient by software according to the reproduction speed of the optical disk device, and determines the optical disk 1 from the pulse interval of the periodic signal 37.
Calculate the rotation frequency of and replace the coefficient by software according to the frequency.

Next, the effect of this embodiment will be described. The positioning device according to the present embodiment is configured to include two compensation methods, a feedforward compensation part and a feedback compensation part, inside the control system. For this reason,
As shown in the frequency characteristic of FIG. 6, it is possible to obtain a high disturbance suppression characteristic in the low frequency region and suppress disturbance such as surface wobbling as compared with the related art, which has only a feedback compensation portion.

Further, in the positioning device according to the present embodiment, the amplitude control means 32 prevents the first control signal 26 from being pulsed, and the first control signal 26
Is as shown in FIG. Especially when there is an obstacle detection delay, it is possible to prevent the pulse-shaped first control signal 26 from unconditionally being applied to the focus actuator 11 by the time the obstacle detection signal 31 is detected. it can. As a result, while the obstacle is passing, the open spot control of the feedforward compensation by the disturbance observer can perform the positioning control of the light spot 7 on the track 2 which is fluctuated by the disturbance such as surface wobbling, and the focus down and the track deviation do not occur. .

Further, normally, the reproduction speed of the optical disk device can be reproduced at the standard speed and a speed several times higher than the standard speed. Therefore, the surface runout and the frequency component of eccentricity change depending on the reproduction speed. For example, in an 8 × speed compatible optical disc device, the frequency component of surface wobbling and eccentricity is about 3 Hz to 9 Hz during reproduction at standard speed, and the frequency component of surface wobbling and eccentricity is about 24 Hz during reproduction at 8 × speed.
Hz to 72 Hz. Therefore, in an optical disk device compatible with 8 × speed, surface wobbling and eccentricity having a frequency component of about 3 Hz to 72 Hz appear. If the cut-off frequency of the low-pass filter is set to correspond to the surface runout and eccentricity frequency components that appear at standard speed, the surface runout and eccentricity frequency components that appear at 2x speed or higher cannot be extracted, and at 8x speed. If settings are made in correspondence with the frequency components of surface wobbling and eccentricity that appear, extra frequency components will be extracted during reproduction at 8 × speed or less, and noise and the like will increase. In addition, since the optical disk device employs a storage method with a constant linear velocity, the frequency components of surface wobbling and eccentricity change depending on the reproduction position of the optical disk. For example, when the cutoff frequency of the low-pass filter is reproduced at the outer peripheral position of the optical disk. If it is set in correspondence with the frequency component of surface wobbling and eccentricity that appears, the frequency component of surface wobbling and eccentricity that appears when playing at a position other than the outer peripheral position cannot be extracted, and it becomes If it is set correspondingly, an extra frequency component will be taken out at the time of reproduction at a position other than the inner peripheral position, and there will be a problem that noise or the like will increase.

On the other hand, in the positioning device according to the present embodiment, the third removing means 35 adjusts the cutoff frequency of the low-pass filter in accordance with the reproduction speed of the optical disk device and the reproduction position of the optical disk. From the second control signal 27, it is possible to create a signal in which excess frequency components other than the surface runout and eccentricity frequency components and noise are removed, and open loop control of feedforward compensation using this signal causes the optical spot 7 to move to the surface. Positioning control can be performed on the track 2 that is fluctuating due to disturbance such as shake, and focus down and track deviation do not occur. Further, since the light spot 7 follows the track 2 which is changing due to disturbance such as surface wobbling even while passing the obstacle, the fluctuation due to the transient characteristic of the control system after passing the obstacle can be reduced, and the recording / reproducing of the signal can be performed. You can shorten the time until.

Further, in the positioning device as described above, the same effect can be obtained by using the first removing means 33 instead of the amplitude limiting means 32. Further, even when the amplitude limiting means 32 or the first removing means 33 is not used, a good effect can be similarly obtained. Further, also in the case of the tracking control means, the same effect can be obtained by adopting the same configuration. Furthermore, DV
It is needless to say that the same effect can be obtained also in the case of a D (digital video disk) device, a magnetic disk device, etc. by adopting the same configuration.

(Fifth Embodiment) The fifth embodiment of the present invention will be described below.
Embodiments will be described with reference to the drawings. FIG.
FIG. 13 is a configuration diagram of focusing control means of an optical disc device according to a fifth embodiment of the present invention. The difference of this embodiment from the third embodiment is that the holding means 38 is provided.

According to the configuration of FIG. 13, the third removing means 3
In No. 5, the second control signal 27 is fetched, the software is read from the first storage unit 19 in accordance with the instruction of the central processing unit 20, and the low-pass filter calculation of the first or higher order is performed, and the calculation result is obtained. Is output. The output of the third removing means 35 is input to the holding means 38. The holding means 38 takes in the output of the third removing means 35, and carries out an operation of holding the taken output of the third removing means 35 in response to a command from the central processing means 20. The output of the holding means 38 is input to the adder 21.

Here, the holding means 38 will be described in detail. The holding means 38 takes in the output of the third removing means 35 and holds the output of the third removing means 35 when the obstacle detection signal 31 is generated while the obstacle detection signal 31 is being generated. While the obstacle detection signal 31 is not generated, the output of the captured third removing means 35 is output as it is.

Next, the effect of this embodiment will be described. The positioning device according to the present embodiment is configured to include two compensation methods, a feedforward compensation part and a feedback compensation part, inside the control system. For this reason,
As shown in the frequency characteristic of FIG. 6, it is possible to obtain a high disturbance suppression characteristic in the low frequency region and suppress disturbance such as surface wobbling as compared with the related art, which has only a feedback compensation portion.

Further, in the positioning device according to the present embodiment, the amplitude control means 32 prevents the first control signal 26 from being pulsed, and the first control signal 26
Is as shown in FIG. Especially when there is an obstacle detection delay, it is possible to prevent the pulse-shaped first control signal 26 from unconditionally being applied to the focus actuator 11 by the time the obstacle detection signal 31 is detected. it can. As a result, while the obstacle is passing, the open spot control of the feedforward compensation by the disturbance observer can perform the positioning control of the light spot 7 on the track 2 which is fluctuated by the disturbance such as surface wobbling, and the focus down and the track deviation do not occur. .

Further, as shown above, the focus error signal 25 becomes indefinite while the obstacle is passing. Due to this influence, the second control signal 27 may fluctuate as shown in FIG. 14C, for example, which may cause focus down and track deviation. Here, if the value of the second control signal 27 at the time of starting to pass through the obstacle can be held during the passage of the obstacle, the influence accompanying the passage of the obstacle can be reduced. However, if there is a delay in the detection of the obstacle, the value of the second control signal 27 at the time when the obstacle starts to pass cannot be held, and FIG.
In this case, too, there is a possibility of causing focus-down and off-track.

On the other hand, in the positioning device according to the present embodiment, the third removing means 35 removes the fluctuation appearing due to the passage of the obstacle from the second control signal 27, as shown in FIG. 14 (e). become. From this, the holding means 3
8 allows the value close to the value of the second control signal 27 at the time of starting to pass through the obstacle to be held, so that the track 2 in which the light spot 7 fluctuates due to disturbance such as surface wobbling.
Positioning control can be performed in the vicinity of, and focus down and track deviation do not occur. Further, since the light spot 7 follows the vicinity of the track 2 which is fluctuating due to disturbance such as surface wobbling even while passing the obstacle, the fluctuation due to the transient characteristic of the control system after passing the obstacle can be reduced, and the signal The time to record and playback can be shortened.

Further, in the positioning device as described above, the same effect can be obtained by using the first removing means 33 instead of the amplitude limiting means 32. Furthermore, the third
The same effect can be obtained by using the second removing means 34 instead of the removing means 35. Further, also in the case of the tracking control means, the same effect can be obtained by adopting the same configuration. Further, it goes without saying that the same effect can be obtained by adopting the same configuration in the case of a DVD (digital video disk) device, a magnetic disk device, or the like.

(Sixth Embodiment) The sixth embodiment of the present invention will be described below.
Embodiments will be described with reference to the drawings. FIG. 15 is a block diagram of the focusing control means of the optical disk device according to the sixth embodiment of the present invention. This embodiment is different from the first embodiment in that the cycle detecting means 36 and the second
The storage means 39 is provided. Reference numeral 37 is a periodic signal output from the period detecting means 36 to the central processing means 20.

According to the configuration of FIG. 15, the cycle detecting means 36
Then, the second control signal 27 is fetched, processing such as polarity determination is performed, and a pulse corresponding to the cycle is output as the cycle signal 37. The periodic signal 37 is input to the central processing means 20. In the second storage means 39, the second control signal 27 is taken in, and a storage operation of storing at least one cycle of the second control signal 27 is performed in accordance with a command from the central processing means 20, and the second cycle of the previous cycle is stored. The control signal 27 of 2 is output. The output of the second storage means 39 is input to the adder 21.
Here, the structure of the cycle detecting means 36 is the same as that described above, and therefore its description is omitted.

Next, regarding the second storage means 39, FIG.
The second storage means 39 will be described with reference to the block diagram of FIG. Second storage means 39
16 is divided into two areas, a storage area 1 and a storage area 2, as shown in FIG. 16, each of which has an area capable of storing at least one cycle value of the second control signal 27. First, the second control signal 27 is stored in the storage area 2, the value of the storage area 1 is output as the output of the second storage means 39 (300 in FIG. 17), and the cycle signal 37 is repeated. When the periodic signal 37 is generated, it is confirmed whether or not the obstacle detection signal 31 is generated during one cycle. When the obstacle detection signal 31 is generated, the process returns to 300 and the above procedure is repeated. If the obstacle detection signal 31 is not generated, the storage area 2
Contents of the storage area 1 to the storage area 1 (303 in FIG. 17), 300
Return to and repeat the above procedure.

Next, the effect of this embodiment will be described. The positioning device according to the present embodiment is configured to include two compensation methods, a feedforward compensation part and a feedback compensation part, inside the control system. For this reason,
As shown in the frequency characteristic of FIG. 6, it is possible to obtain a high disturbance suppression characteristic in the low frequency region and suppress disturbance such as surface wobbling as compared with the related art, which has only a feedback compensation portion.

Further, in the positioning device according to the present embodiment, the amplitude control means 32 prevents the first control signal 26 from being pulsed, and the first control signal 26
Is as shown in FIG. Especially when there is an obstacle detection delay, it is possible to prevent the pulse-shaped first control signal 26 from unconditionally being applied to the focus actuator 11 by the time the obstacle detection signal 31 is detected. it can. As a result, while the obstacle is passing, the open spot control of the feedforward compensation by the disturbance observer can perform the positioning control of the light spot 7 on the track 2 which is fluctuated by the disturbance such as surface wobbling, and the focus down and the track deviation do not occur. .

Furthermore, if there is an obstacle on the optical disc 1,
While the light spot 7 is tracing on this, the focus error signal 25 is indefinite. In the prior art, since only feedback compensation is performed, the position of the light spot 7 cannot be controlled on the track 2 which is fluctuating due to disturbance such as surface wobbling while the obstacle is passing. On the other hand, the positioning device according to the present invention comprises the feedback compensation part and the feedforward compensation part, and the second storage means 39 is used, and the feedforward compensation signal is not affected by the obstacle, for example, one cycle. Previous second control signal 2
7 is used. As a result, while the obstacle is passing, the light spot 7 is subjected to the open loop control of the feedforward compensation.
Can be controlled to be positioned on the track 2 which is fluctuated by a disturbance such as surface wobbling, and focus down and track deviation do not occur. Further, since the light spot 7 follows the track 2 which is changing due to disturbance such as surface wobbling even while passing the obstacle, the fluctuation due to the transient characteristic of the control system after passing the obstacle can be reduced, and the recording / reproducing of the signal can be performed. You can shorten the time until.

Further, in the positioning device as described above, the same effect can be obtained by using the first removing means 33 instead of the amplitude limiting means 32. Further, even when the amplitude limiting means 32 or the first removing means 33 is not used, a good effect can be similarly obtained. Further, also in the case of the tracking control means, the same effect can be obtained by adopting the same configuration. Furthermore, DV
It is needless to say that the same effect can be obtained also in the case of a D (digital video disk) device, a magnetic disk device, etc. by adopting the same configuration.

(Seventh Embodiment) The seventh embodiment of the present invention will be described below.
Embodiments will be described with reference to the drawings. FIG.
FIG. 13 is a configuration diagram of focusing control means of an optical disc device according to a seventh embodiment of the present invention. The difference of this embodiment from the fourth embodiment is that the second storage means 39 is provided.

According to the configuration of FIG. 18, the cycle detecting means 36
Then, the second control signal 27 is taken in, processing such as polarity determination is performed, and a pulse corresponding to the cycle is output as the cycle signal 37. The periodic signal 37 is input to the central processing means 20. In the second storage means 39, while taking in the output of the third removing means 35, a storage operation for storing at least one cycle of the output of the third removing means 35 is performed in response to a command from the central processing means 20, The output of the third removing means 35 in the previous cycle is output. The output of the second storage means 39 is input to the adder 21. Here, the cycle detection means 36
Since the configuration of the second storage means 39 is the same as that described above, description thereof will be omitted.

Next, the effect of this embodiment will be described. The positioning device according to the present embodiment is configured to include two compensation methods, a feedforward compensation part and a feedback compensation part, inside the control system. For this reason,
As shown in the frequency characteristic of FIG. 6, it is possible to obtain a high disturbance suppression characteristic in the low frequency region and suppress disturbance such as surface wobbling as compared with the related art, which has only a feedback compensation portion.

Further, in the positioning device according to the present embodiment, the amplitude control means 32 prevents the first control signal 26 from being pulsed, and the first control signal 26
Is as shown in FIG. Especially when there is an obstacle detection delay, it is possible to prevent the pulse-shaped first control signal 26 from unconditionally being applied to the focus actuator 11 by the time the obstacle detection signal 31 is detected. it can. As a result, while the obstacle is passing, the open spot control of the feedforward compensation by the disturbance observer can perform the positioning control of the light spot 7 on the track 2 which is fluctuated by the disturbance such as surface wobbling, and the focus down and the track deviation do not occur. .

Furthermore, if there is an obstacle on the optical disc 1,
While the light spot 7 is tracing on this, the focus error signal 25 is indefinite. In the prior art, since only feedback compensation is performed, the position of the light spot 7 cannot be controlled on the track 2 which is fluctuating due to disturbance such as surface wobbling while the obstacle is passing. On the other hand, the positioning device according to the present invention comprises the feedback compensation part and the feedforward compensation part, and the second storage means 39 is used, and the feedforward compensation signal is not affected by the obstacle, for example, one cycle. Previous second control signal 2
7 is used, and the third removing means 35 removes extra frequency components such as noise from the second control signal 27. Thus, while the obstacle is passing, the light spot 7 can be positioned and controlled on the track 2 which is fluctuated by disturbance such as surface wobbling by the open-loop control of the feed-forward compensation, and focus-down and off-track do not occur. Further, since the light spot 7 follows the track 2 which is changing due to disturbance such as surface wobbling even while passing the obstacle, the fluctuation due to the transient characteristic of the control system after passing the obstacle can be reduced, and the recording / reproducing of the signal can be performed. You can shorten the time until.

Further, in the positioning device as described above, the same effect can be obtained by using the first removing means 33 instead of the amplitude limiting means 32. Further, even when the amplitude limiting means 32 or the first removing means 33 is not used, a good effect can be similarly obtained. Further, the same effect can be obtained by using the second removing means 34 instead of the third removing means 35. Further, also in the case of the tracking control means, the same effect can be obtained by adopting the same configuration. Further, it goes without saying that the same effect can be obtained by adopting the same configuration in the case of a DVD (digital video disk) device, a magnetic disk device, or the like.

(Eighth Embodiment) The eighth embodiment of the present invention will be described below.
Embodiments will be described with reference to the drawings. FIG.
FIG. 13 is a partial configuration diagram showing an example in which an interpolation means 40 is added to the sixth to seventh embodiments.

According to the configuration shown in FIG. 19, the interpolation means 40 takes in the output of the second storage means 39, performs linear approximation, approximation by a quadratic curve or the like, and interpolates between storage intervals. The output of the interpolation means 39 is input to the adder 21.

Here, the interpolation means 40 will be described in detail. The interpolation means 40 can also perform interpolation by performing approximation using a quadratic curve or the like, but in the present embodiment, interpolation is performed by linear approximation. Hereinafter, the output of the second storage means 39 is represented by U _2M (k _M ) and the output of the interpolation means 40 is Y _I (k).
Expressed by However, k _M represents the time index of the storage interval of the second storage means 39.

Since U _2M (k _M ) is the value stored in the second storage means 39, the future value U _2M (k _M +1) can be used. Here, when the storage interval of the second storage means 39 when the sampling interval of the first calculation means 17 is 1, is T _I , the present value U _2M (k _M ) to the future value U
The increment during the sampling interval of the first computing means 17 during _2M (k _M +1) is as shown in Equation 10.

[0116]

(Equation 10)

Therefore, the increment between U _2M (k _M ) and U _2M (k _M +1) is interpolated by adding an increment to U _2M (k _M ) at each sampling interval of the first calculating means 17. can do. A waveform diagram showing the above procedure is shown in FIG.

Next, the effect of this embodiment will be described. In addition to the effects shown in the sixth to seventh embodiments, the second control signal 27 is a signal that compensates for disturbance such as surface wobbling in a feedforward manner.
Since the frequency component of the disturbance such as surface wobbling is 100 Hz or less, the second control signal 27 is adjusted in accordance with the sampling interval of 10 kHz or more when the first calculation means 17 is calculated.
Does not have to be stored each time is calculated. For example, even if feedforward compensation is performed using a value stored at a sampling interval of 1 kHz or less, which is about 10 times the frequency component such as surface wobbling, a similar effect can be obtained. By doing so, the storage area can be reduced and the circuit scale can be reduced.

Further, by using the interpolating means 40 of the present embodiment, by interpolating between the storage intervals of the output of the second storage means 39, the second control signal 27 before storage is approximated, Since a smooth signal can be restored, a good effect can be obtained.

Further, in the positioning device as described above, the same effect can be obtained by adopting the same configuration also in the case of the tracking control means. Furthermore, D
It goes without saying that the same effect can be obtained also in the case of a VD (digital video disk) device, a magnetic disk device or the like by adopting the same configuration.

(Ninth Embodiment) The ninth embodiment of the present invention will be described below.
Embodiments will be described with reference to the drawings. FIG.
FIG. 9 is a partial configuration diagram showing an example of a case where a switch 41 is added to the third to eighth embodiments.

According to the configuration of FIG. 21, in the switch 41, the second control signal 27, the output of the second removing means 34, the output of the third removing means 35, the output of the holding means 38,
Either the output of the second storage means 39 or the output of the interpolation means 40 is fetched, and by the command of the central processing means 20,
Second control signal 27, output of second removing means 34, third
One of the output of the removing unit 35, the output of the holding unit 38, the output of the second storage unit 39, and the output of the interpolation unit 40 is selected. The output of the switch 41 is the adder 25.
To enter.

Here, the switch 41 will be described in detail. The switching device 41 normally has the second control signal 27.
Although it is switched to the side, while the obstacle detection signal 31 is generated, the second removing means 34, the third removing means 35,
The output is switched to one of the holding means 38, the second storage means 39, and the interpolation means 40.

Next, the effect of this embodiment will be described. In addition to the effects shown in the third to seventh embodiments, the switching device 41 normally operates in the second control signal 2
Since it is switched to the 7 side, it means that disturbance compensation such as surface wobbling is compensated in real time while there is no obstacle. Therefore, the positioning device according to the present embodiment can obtain a good effect with respect to transient characteristics and the like when a shock or the like is applied to the control system.

Further, in the positioning device as described above, the same effect can be obtained by adopting the same configuration also in the case of the tracking control means. Furthermore, D
It goes without saying that the same effect can be obtained also in the case of a VD (digital video disk) device, a magnetic disk device or the like by adopting the same configuration.

(Tenth Embodiment) A tenth embodiment of the present invention will be described below with reference to the drawings. FIG.
2 is the third correction means 4 in the first to ninth embodiments.
It is a partial block diagram which shows an example when 2 is added.

According to the configuration of FIG. 22, the third correction means 4
In 2, the first control signal 26 is fetched and the first control signal 26 is corrected by the instruction of the central processing means 20. The output of the third correcting means 42 is input to any of the amplitude limiting means 32, the adding means 21, and the first removing means 33.

Now, the third correction means 42 will be described in detail. The third correction means 42 uses the first control signal 2
The first control signal 26 is taken in and output while the obstacle detection signal 31 is generated, and the first control signal 26 is output while the obstacle detection signal 31 is not generated. 26 is output as it is.

Next, the effect of this embodiment will be described. In addition to the effects shown in the first to ninth embodiments, as described above, during the passage of the obstacle, the first control signal is affected by the indefinite focus error signal 25. 26 has a pulse shape as shown in FIG. The first control signal 26 is the focus actuator 11
May cause focus down. On the other hand, in the positioning device according to the present embodiment, the first control signal 26 is set to zero by the third correction means 42 while the obstacle detection signal 31 is generated.
It becomes like FIG.7 (d). Further, after this, when passing through the amplitude limiting means 32, the first control signal 26 becomes as shown in FIG.
become that way. As a result, while the obstacle is passing, the position of the light spot 7 can be controlled to the track 2 which is fluctuated by the disturbance such as surface wobbling by the open loop control of the feedforward compensation by the disturbance observer, and the focus down and the track deviation do not occur. .

Further, in the positioning device as described above, the same effect can be obtained by adopting the same structure also in the case of the tracking control means. Furthermore, D
It goes without saying that the same effect can be obtained also in the case of a VD (digital video disk) device, a magnetic disk device or the like by adopting the same configuration.

[0131]

As described above, according to the present invention, the second
The calculation means of is composed of a disturbance observer for estimating disturbance such as surface wobbling and eccentricity, and by adding the estimated second disturbance control signal to the first control signal in a feedforward manner, It is possible to follow disturbances such as eccentricity with high accuracy.

Further, the second control signal is stored in the storage means and the signal of the previous cycle is used, or the second control signal is passed through the second removing means or the third removing means to obtain the high frequency component. By using a signal from which the first control signal has been removed, the first control signal is also passed through the amplitude limiting means to prevent the first control signal from suddenly increasing during passage of the obstacle. Not affected by passage. For this reason, it is possible to prevent focus-down and off-track, and also shorten the time until recording / reproduction of a signal after passing an obstacle, and perform stable recording / reproduction operation.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a focus servo unit of an optical disc device according to a first embodiment of the present invention.

FIG. 2 is an enlarged view showing a state where there is an obstacle on the optical disc.

FIG. 3 is a waveform diagram showing a relationship between an obstacle and an obstacle detection signal.

FIG. 4 is a flowchart showing a calculation procedure of a focus servo unit.

FIG. 5 is a characteristic diagram showing the input / output characteristics of the amplitude limiting means.

FIG. 6 is a frequency characteristic diagram showing a disturbance suppression effect according to the present invention.

FIG. 7 is a waveform diagram showing each signal when passing an obstacle.

FIG. 8 is a configuration diagram of a focus servo unit of an optical disc device according to a second embodiment of the present invention.

FIG. 9 is a flowchart showing a calculation procedure of first removing means.

FIG. 10 is a configuration diagram of a focus servo unit of an optical disc device according to a third embodiment of the present invention.

FIG. 11 is a configuration diagram of a focus servo unit of an optical disc device according to a fourth embodiment of the present invention.

FIG. 12 is a waveform diagram showing an outline of the operation of the cycle detection means.

FIG. 13 is a configuration diagram of focus servo means of an optical disc device according to a fifth embodiment of the present invention.

FIG. 14 is a waveform chart showing the effect of the holding means.

FIG. 15 is a configuration diagram of focus servo means of an optical disc device according to a sixth embodiment of the present invention.

FIG. 16 is a configuration diagram showing a configuration of second storage means.

FIG. 17 is a flowchart showing an outline of the operation of the second storage means.

FIG. 18 is a configuration diagram of focus servo means of an optical disc device according to a seventh embodiment of the present invention.

FIG. 19 is a configuration diagram of focus servo means of an optical disc device according to an eighth embodiment of the present invention.

FIG. 20 is a waveform diagram showing the calculation procedure of the interpolation means.

FIG. 21 is a configuration diagram of focus servo means of an optical disc device according to a ninth embodiment of the present invention.

FIG. 22 is a configuration diagram of focus servo means of an optical disc device according to a tenth embodiment of the present invention.

[Explanation of symbols]

 1 Optical Disc 2 Track 3 Disc Motor 4 Pickup 5 Laser Light 6 Semiconductor Laser 7 Light Spot 8 Objective Lens 9 Reflected Light 10 Sensor 11 Focus Actuator 12 Tracking Actuator 13 Thread 14 Linear Actuator 15 Amplifying Means 16 AD Converter 17 First Computing Means 18 Second Computing Means 19 First Storage Means 20 Central Processing Means 21 Adders 22 DA Converters 23 Drivers 24 IC Chips 25 Focus Error Signals 26 First Control Signals 27 Second Control Signals 28 Third Control Signals 29 Information signal 30 Obstacle detecting means 31 Obstacle detecting signal 32 Amplitude limiting means 33 First removing means 34 Second removing means 35 Third removing means 36 Period detecting means 37 Periodic signal 38 Holding means 39 Second storage Means 40 Interpolation means 41 Switcher 42 Third correction means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhiro Mitsui 502 Jinritsu-cho, Tsuchiura-shi, Ibaraki Machinery Research Institute, Hiritsu Manufacturing Co., Ltd. (72) Inventor Hidehito Yamada, 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Hitachi, Ltd. Video Information Media Division

Claims (22)

[Claims] 1. An optical information recording / reproducing device for irradiating a track on an optical information recording medium with a light spot of a laser beam focused by an objective lens under focusing control and tracking control. In the positioning device of the recording / reproducing apparatus, there is an amplifying unit that generates a position error signal and an information signal, which are deviations of the light spot from the track, and a trace position of the light spot on the optical information recording medium. Obstacle detecting means for detecting an obstacle and outputting an obstacle detection signal,
Light spot moving means for moving the light spot in the focus direction and the tracking direction of the optical information recording medium, and a state feedback compensation including a phase compensation calculation such as phase lead / lag compensation or a state estimator for fetching the position error signal. First calculation means for performing a calculation and outputting a first control signal as a result of the calculation; first correction means for correcting the first control signal after the first calculation means; A second computing unit that takes in the position error signal and a predetermined third control signal, performs a disturbance estimation calculation by a disturbance observer, and outputs a second control signal as the calculation result, and the first correction unit. Adding means for adding the output and the second control signal to output the third control signal;
A positioning device for an optical information recording / reproducing apparatus, comprising: a driving unit that drives the light spot moving unit according to the third control signal. 2. Optical information for recording / reproducing information by irradiating a track on an optical information recording medium with a light spot of a laser beam focused by an objective lens under focusing control and tracking control. In the positioning device of the recording / reproducing apparatus, there is an amplifying unit that generates a position error signal and an information signal, which are deviations of the light spot from the track, and a trace position of the light spot on the optical information recording medium. Obstacle detecting means for detecting an obstacle and outputting an obstacle detection signal,
Light spot moving means for moving the light spot in the focus direction and the tracking direction of the optical information recording medium, and a state feedback compensation including a phase compensation calculation such as phase lead / lag compensation or a state estimator for fetching the position error signal. First calculation means for performing a calculation and outputting a first control signal as a result of the calculation; first correction means for correcting the first control signal after the first calculation means; A second computing unit that takes in the position error signal and a predetermined third control signal, performs a disturbance estimation computation by a disturbance observer, and outputs a second control signal as the computation result; and a second computing unit of the second computing unit. After that, the second correction means for correcting the second control signal, the output of the first correction means and the output of the second correction means are added, and the third control signal is output. Adder When the positioning device of the optical information recording and reproducing apparatus characterized by comprising a driving means for driving the light spot movement means by the control signal of the third. 3. The second control signal is fetched and the second control signal is received.
Of the second control signal or the second correcting means after the cycle detecting means for detecting the cycle of the control signal and outputting the periodic signal, and the second computing means or the second correcting means. The output is stored according to the rotational position of the optical information recording medium by the periodic signal, the presence or absence of an obstacle in storage is determined by the obstacle detection signal, and the optical information recording medium is determined by the periodic signal. 3. The positioning device for an optical information recording / reproducing apparatus according to claim 1, further comprising a storage unit that outputs a previously stored signal in correspondence with the rotational position of. 4. The storage interval of the second control signal or the output of the second correction means in the storage means is set to the second storage interval.
4. The positioning device for an optical information recording / reproducing apparatus according to claim 3, wherein the positioning means is longer than the calculation sampling interval of the calculating means. 5. The positioning device for an optical information recording / reproducing apparatus according to claim 4, further comprising an interpolating means for interpolating the signal stored in the storage means when the signal is output. 6. The second control signal and the output of the second correction means, the output of the storage means, or the output of the interpolation means are fetched, and when the obstacle detection signal is not generated, When the second control signal is selected and the obstacle detection signal is generated, either the output of the second correction means, the output of the storage means or the output of the interpolation means is selected, Switching means for outputting the selected signal; and adding means for adding the output of the first control signal or the first correcting means and the output of the switching means to output the third control signal. The positioning device for an optical information recording / reproducing apparatus according to any one of claims 1 to 5, further comprising: 7. The first correction means is an amplitude limiting means for outputting the set value as the first control signal when the taken-in first control signal exceeds a set value. 7. A positioning device for an optical information recording / reproducing device according to claim 1, wherein the positioning device is an optical information recording / reproducing device. 8. The method according to claim 1, wherein the first correcting means is a first removing means for removing a high frequency component of the fetched first control signal. Positioning device for the optical information recording / reproducing device described. 9. The method according to claim 2, wherein the second correcting means is a second removing means for removing a high frequency component of the captured second control signal. Positioning device for the optical information recording / reproducing device described. 10. The second correcting means is a third removing means for removing a high frequency component of the captured second control signal, and the third removing means captures the second high frequency component. 9. The optical information recording / reproducing according to claim 2, wherein a frequency band for removing a high frequency component of the control signal changes in accordance with the number of rotations of the optical information recording medium. Device positioning device. 11. The second correcting means is either the second removing means or the third removing means for removing the high frequency component of the captured second control signal, and thereafter, the obstacle detection. 9. Holding means for holding either the output of the second removing means or the output of the third removing means while a signal is being generated. A positioning device for the optical information recording / reproducing apparatus according to item 1. 12. A track on an optical information recording medium,
The light spot of the laser light condensed by the objective lens,
By irradiating while focusing control and tracking control, a positioning device of an optical information recording / reproducing device for recording / reproducing information generates a position error signal and an information signal which are deviations of the light spot from the track. Amplification means, obstacle detection means for detecting an obstacle existing at a trace position of the optical spot on the optical information recording medium and outputting an obstacle detection signal, and the optical spot for the optical information recording medium. Optical spot moving means for moving in the focus direction and the tracking direction, and the position error signal is taken in to perform a phase compensation calculation such as phase advance / delay compensation or a state feedback compensation calculation including a state estimator.
Of the position error signal and a predetermined third control signal, performs disturbance estimation calculation by a disturbance observer, and outputs the second calculation result as the second calculation result.
Second calculation means for outputting the control signal of the above, and after the second calculation means, the second control signal is fetched, the high frequency component of the fetched second control signal is removed, and the removal is performed. The frequency band of the third information removing means whose frequency band changes in accordance with the number of rotations of the optical information recording medium, the first control signal and the output of the third removing means are added, and the third removing means is added. 2. A positioning device for an optical information recording / reproducing apparatus, comprising: an adding means for outputting the control signal of 1. and a driving means for driving the light spot moving means by the third control signal. 13. A track on an optical information recording medium,
The light spot of the laser light condensed by the objective lens,
By irradiating while focusing control and tracking control, a positioning device of an optical information recording / reproducing device for recording / reproducing information generates a position error signal and an information signal which are deviations of the light spot from the track. Amplification means, obstacle detection means for detecting an obstacle existing at a trace position of the optical spot on the optical information recording medium and outputting an obstacle detection signal, and the optical spot for the optical information recording medium. Optical spot moving means for moving in the focus direction and the tracking direction, and the position error signal is taken in to perform a phase compensation calculation such as phase advance / delay compensation or a state feedback compensation calculation including a state estimator.
Of the position error signal and a predetermined third control signal, performs disturbance estimation calculation by a disturbance observer, and outputs the second calculation result as the second calculation result.
Second calculation means for outputting the control signal, cycle detection means for fetching the second control signal, detecting the cycle of the second control signal, and outputting a cycle signal, and the second calculation means. After that, the second control signal is stored corresponding to the rotational position of the optical information recording medium by the periodic signal, and the presence or absence of the stored obstacle is determined by the obstacle detection signal,
Storage means for outputting a signal previously stored corresponding to the rotation position of the optical information recording medium by the periodic signal, and the third control by adding the first control signal and the output of the storage means. A positioning device for an optical information recording / reproducing apparatus, comprising: an addition means for outputting a signal; and a driving means for driving the light spot moving means by the third control signal. 14. A track on an optical information recording medium,
The light spot of the laser light condensed by the objective lens,
By irradiating while focusing control and tracking control, a positioning device of an optical information recording / reproducing device for recording / reproducing information generates a position error signal and an information signal which are deviations of the light spot from the track. Amplification means, obstacle detection means for detecting an obstacle existing at a trace position of the optical spot on the optical information recording medium and outputting an obstacle detection signal, and the optical spot for the optical information recording medium. Optical spot moving means for moving in the focus direction and the tracking direction, and the position error signal is fetched, phase compensation calculation such as phase advance / delay compensation or state feedback compensation calculation including a state estimator is performed, and the first calculation result is obtained.
Of the position error signal and a predetermined third control signal, performs disturbance estimation calculation by a disturbance observer, and outputs the second calculation result as the second calculation result.
Second calculation means for outputting the control signal, cycle detection means for fetching the second control signal, detecting the cycle of the second control signal, and outputting a cycle signal, and the second calculation means. After that, the second control signal is fetched, the high frequency component of the fetched second control signal is removed, and the frequency band to be removed changes in accordance with the rotation speed of the optical information recording medium. And a third removing means for storing the output of the third removing means corresponding to the rotational position of the optical information recording medium by the periodic signal after the third removing means. Judgment of the presence of obstacles in memory by the detection signal,
Storage means for outputting a signal previously stored corresponding to the rotational position of the optical information recording medium by the periodic signal, and the third control by adding the first control signal and the output of the storage means. A positioning device for an optical information recording / reproducing apparatus, comprising: an addition means for outputting a signal; and a driving means for driving the light spot moving means by the third control signal. 15. The storage interval of the output of the second control signal or the output of the third removing means in the storage means is longer than the calculation sampling interval of the first calculating means. Item 13. A positioning device for an optical information recording / reproducing device according to item 13 or 14. 16. The positioning device for an optical information recording / reproducing apparatus according to claim 15, further comprising an interpolating unit that interpolates the signal stored in the storage unit when the signal is output. 17. The second control signal and the output of the third removing means, the output of the storage means, or the output of the interpolating means are fetched, and when the obstacle detection signal is not generated, When the second control signal is selected and the obstacle detection signal is generated, either the output of the third removing means, the output of the storage means or the output of the interpolating means is selected, Switching means for outputting the selected signal; and an adding means for adding the first control signal and the output of the switching means to the first control signal to output the third control signal. The positioning device for an optical information recording / reproducing apparatus according to any one of claims 12 to 16, characterized in that. 18. A third compensating means for setting the first control signal to zero while the obstacle detecting means is detecting an obstacle after the first computing means. The positioning device for an optical information recording / reproducing apparatus according to any one of claims 1 to 17, characterized in that: 19. The magnitude of the set value of the amplitude limiting means is different between a first period after starting the focusing control or the tracking control and a second period after that. The positioning device for the optical information recording / reproducing apparatus according to claim 7. 20. The set value of the amplitude limiting means is not less than the operating range of the first control signal when the obstacle is not present and is not more than twice the operating range. A positioning device for the optical information recording / reproducing apparatus according to item 1. 21. The first removing means, the second removing means, and the third removing means start removing high-frequency components of the captured first control signal or second control signal. The frequency is equal to or higher than the maximum rotation frequency of the optical information recording rotary medium and is 1 of the maximum rotation frequency.
15. The positioning device for an optical information recording / reproducing apparatus according to claim 8, which is 0 times or less. 22. The first calculation means, the second calculation means, the cycle detection means, the storage means, the addition means, the switching means, the first correction means, the second
22. The positioning device for an optical information recording / reproducing apparatus according to claim 1, wherein said correcting means and said third correcting means are constituted by one IC chip.