JPH09320075A - Head positioning control apparatus for optical disk apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a stable tracking servo loop without increase of the cost, by raising the estimation band of disturbance observer even when an actuator, which difficult to raise the high-order resonance frequency, used. SOLUTION: A tracking error signal TEST detected by a tracking error signal detecting means 2 is input to a notch filter 5 via a lowpass filter LPF 4 and an A/D converter 3. An output of the notch filter 5 is input to a disturbance observer 8 via a phase compensating means 6 and a phase inverting means 7. A positioning compensating signal as an output of the phase compensating means 6 and a disturbance compensating signal as an output of the phase compensating means 6 are added in an adding means 9 to become an operation signal. This operation signal is then converted to an analog signal and is then input to a driven circuit 11 and then to a tracking actuator 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head positioning control device for an optical disk device, and more particularly to a head positioning control device for an optical disk device characterized by a portion for estimating a disturbance from a position error signal and a drive signal for an actuator and compensating for the disturbance. Regarding

[0002]

2. Description of the Related Art In an optical disk device, a disk is rotating at a high speed, so that it vibrates at a rotation frequency, and this vibration appears as a disturbance in a position signal. In this case, an external force such as a frictional force acting on the actuator also becomes a disturbance of the control system, which causes a track following error. It is known to use a disturbance observer as a means for compensating for these disturbances. For example, Vol. 30, No
7, 828/835 (1994) “Application of disturbance observer to magnetic disk device head positioning control system”,
A disturbance observer that estimates the disturbance from the position error signal and the drive signal of the actuator is configured, and the output signal is added to the drive signal to compensate for the disturbance.

In order to increase the effect of suppressing disturbance, it is necessary to increase the estimated band of the disturbance observer. This is especially necessary when the disturbance observer is effective against static friction. However, when the actuator has higher-order resonance, the higher-order resonance component appears in the output of the disturbance observer when the disturbance observer band is increased to improve the estimation performance. Therefore, the higher order resonance limits the band of the disturbance observer.

Therefore, in Japanese Patent Laid-Open No. 5-134707, a notch filter is added to the output of the disturbance observer to remove the influence of higher-order resonance and raise the estimated band of the disturbance observer.

A head positioning control device for a conventional optical disk device will be described below with reference to the drawings. FIG.
It is a block diagram of a head positioning control device of a conventional optical disk device.

As shown in FIG. 8, in the conventional head positioning control device 100 of the optical disk device, the tracking error signal detection unit 101 detects the position error between the track position signal indicating the center position of the track and the spot position signal.
Is output as a tracking error signal (TES). The tracking error signal detection unit 101 includes an optical system (not shown) and an amplifier 101a.

The tracking error signal (TES) is input to the first notch filter 103 via the phase compensating unit 102, and its output becomes a positioning compensation signal, and this positioning compensation signal is added to the disturbance compensation signal from the disturbance observer 104. Is operated and becomes an operation signal. Then, this operation signal is input to the tracking actuator 106 via the drive circuit 105.

The tracking actuator 106 has a thrust constant of Kf (N / A) and a transfer function of 1 excluding higher-order resonance.
/ Ms ² and a transfer function G of higher resonance, Kf · G /
It is represented by Ms ² .

Further, the disturbance observer 104 is supplied with an operation signal as a drive signal for the tracking actuator 106 and a tracking error signal (TES) whose phase is inverted by the phase inverting section 107 as a position signal.
The output of the disturbance observer 104 is input to the second notch filter 108, and the disturbance compensation signal is generated.

The phase compensator 102, the first notch filter 103, the second notch filter 108 and the disturbance observer 104 are analog circuits or DSPs.
It can also be realized by a digital filter using a microprocessor such as (digital signal processor).

Next, the structure of the disturbance observer 104 is shown in FIG.
This will be described with reference to FIG. FIG. 9 is an equivalent functional block diagram of the control system of the positioning control device in FIG. In FIG. 9, the portion surrounded by the dotted line is the disturbance observer 104, the Laplace operator is represented by s, the detection sensitivity of the tracking error signal is K2 (V / m), and the gain of the drive circuit 105 is Ka (A / V). , Tracking actuator 10
The thrust constant of 6 is (N / A), the transfer function excluding higher-order resonance is 1 / Ms ² and the transfer function of higher-order resonance is G, where M (kg) is the mass of the movable part on which the head is mounted. Disturbance D
It is represented as (N).

The disturbance observer 104 is a continuous-time same-dimensional observer made from a transfer function model from the operation signal to the spot position without considering higher-order resonance.
If the model transfer function is G _act , then G _act = K1 · K2 / Ms ² .

Gains K1, l1, l2, and H are gains of the observer of the disturbance and are represented by the following equation.

[0014] When K1 = Ka · Kf l1 = 2ζ · ω / K2 l2 = ω 2 / K2 H = -l2 / K1 the angular frequency of the vibration that you want to suppress ω1, ω is set to a frequency of several times, ζ Is set to 0.5 to 4th place.

Here, the actuator has no higher-order resonance (that is, when G = 1), and the second notch filter 10
When the disturbance compensation signal in the case where 8 is not provided is w ₀ , it is expressed by the following equation, and the frequency characteristic of the gain of w ₀ / D is shown in FIG.
It becomes like the solid line shown in 0.

W ₀ = −ω ² / (s ² + 2ζ · ω · s + ω ² ) / K 1 · D Further, there is a high-order resonance, and the disturbance compensation signal when the second notch filter 108 is arranged is w ₁ Then, the frequency characteristic of the gain of w ₁ / D is as shown by the broken line in FIG. In this case, the variation of the gain due to the higher-order resonance is estimated as the disturbance with respect to the ideal model of the observer, so that a peak occurs in the frequency component of the higher-order resonance.

Further, the tracking actuator 10
6 has a high-order resonance, and when the second notch filter 108 that attenuates this high-order resonance is provided (in the case of FIG. 9), the disturbance compensation signal is w _2, and the frequency characteristic of w ₂ / D gain is shown. Is as shown by the dashed line in FIG. In this case, since the frequency component of the higher order resonance is removed from the estimated disturbance value, the higher order resonance is not affected. Therefore, the band of disturbance estimation can be increased.

[0018]

However, if the output of the disturbance observer is provided with a notch filter that removes frequency components of high-order resonance in order to increase the estimated band of the disturbance observer, the following problems occur.

First, when the notch filter of the disturbance observer is calculated by software, a calculation time delay occurs due to the addition of the notch filter. This leads to a decrease in the phase margin and gain margin of the tracking servo system. Therefore, even if the estimated band of the disturbance observer increases, the stability of the tracking servo system will be impaired.

Further, since the filter calculation is normally performed in the interrupt process for each sampling period, when the process is increased and the calculation cannot be completed within the sampling period, the sampling frequency is lowered or a higher speed calculation is performed. A processor or the like may be required. Also in this case, the phase margin and the gain margin are reduced and the cost is increased.

Further, when the disturbance observer is composed of an analog circuit, the number of circuit elements is increased by adding a notch filter. Therefore, the cost is increased due to the addition of new parts and the increase of the required mounting space.

The present invention has been made in view of the above circumstances, and in particular, even when an actuator in which it is difficult to increase the frequency of high-order resonance, such as a fine-coarse integral drive type actuator, disturbance is disturbed. An object of the present invention is to provide a head positioning control device for an optical disc device, which can increase the estimated band of the observer and can obtain stable tracking servo loop characteristics without increasing the cost.

[0023]

According to a first aspect of the present invention, there is provided a head positioning control device for an optical disk device, which comprises a tracking actuator for moving a position of a laser beam irradiated on the optical disk in a radial direction of the optical disk. ,
A tracking error signal detecting means for detecting a tracking error signal indicating a positional deviation between the laser beam and the information track on the optical disc, and a frequency component of higher-order resonance of the tracking actuator which receives the tracking error signal are removed. A notch filter, a phase compensating means having an output of the notch filter as an input, a drive circuit for driving an actuator according to a signal obtained by adding a disturbance compensation signal to the output of the phase compensating means, an output of the notch filter and the drive circuit. Input signal and the disturbance observer for generating the disturbance compensation signal.

In the head positioning control device for an optical disk device according to claim 1 of the present invention, the disturbance observer receives the output of the notch filter and the input signal of the drive circuit as input, and generates the disturbance compensation signal. Then, the disturbance observer is operated with respect to the model in which the frequency component of the higher-order resonance of the tracking actuator is removed, the disturbance observer is prevented from being affected by the higher-order resonance, and a new notch filter is added. Even if it does not exist, a higher-order resonance component does not appear in the output of the disturbance observer, the estimated band of the disturbance observer is increased, and stable tracking servo loop characteristics can be obtained without increasing the cost. A head positioning control device for an optical disk device according to a second aspect of the present invention is a tracking actuator for moving the position of the laser light irradiated onto the optical disk in the radial direction of the optical disk, the laser light and the above-mentioned optical disk. A tracking error signal detecting means for detecting a tracking error signal indicating a positional deviation from an information track, a phase compensating means for receiving the tracking error signal, and a signal obtained by adding a disturbance compensating signal to the output of the phase compensating means are inputted. Notch filter to
A drive circuit that drives an actuator according to the output of the notch filter, and a disturbance observer that receives the tracking error signal and the input signal of the notch filter and that generates the disturbance compensation signal are configured.

In the head positioning control device for an optical disk device according to a second aspect of the present invention, the disturbance observer receives the tracking error signal and the input signal of the notch filter and generates the disturbance compensation signal.
The disturbance observer is operated with respect to the model in which the frequency component of the higher-order resonance of the tracking actuator is removed, the disturbance observer is prevented from being affected by the higher-order resonance, and a new notch filter is not added. Also makes it possible to increase the estimated band of the disturbance observer without the appearance of high-order resonance components in the output of the disturbance observer, and to obtain stable tracking servo loop characteristics without increasing the cost.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

1 to 5 relate to the first embodiment of the present invention, FIG. 1 is a block diagram showing the configuration of a head positioning control device, and FIG. 2 is a first diagram for explaining the configuration of the tracking actuator of FIG. FIG. 3 is a second explanatory diagram illustrating the configuration of the tracking actuator of FIG.
FIG. 4 is a functional block diagram showing equivalent functional blocks of the control system of the positioning control device of FIG. 1, and FIG. 5 is a flowchart explaining the operation of the positioning control device of FIG.

Although not shown, the optical disk device supplies a spindle motor for rotating the optical disk provided with information tracks, a moving optical system for irradiating the optical disk with a light beam, and a laser beam as a light source of the light beam. A fixed optical system including a laser diode and a photodetector that detects return light from an optical disc through a moving optical system; and a tracking control device that performs tracking control by detecting a tracking error signal (TES) from the photodetector of the fixed optical system. It is configured with. The head positioning control device of the present embodiment is, for example, a device provided in the tracking control device, and hereinafter, only the configuration related to the head positioning control device of the present embodiment will be described, and the head positioning control device of the present embodiment will be described. Since the structure which does not exist is publicly known, the description thereof will be omitted.

As shown in FIG. 1, in the head positioning control device 1 of the present embodiment, the tracking error signal detector 2 has a track position signal indicating the center position of the track and a spot position signal indicating the spot position of the light beam. The position error between and is output as a tracking error signal (TES). Here, the tracking error signal detector 2
Is composed of an optical system (not shown) and an amplifier 2a.

Then, the tracking error signal (TE
S) is input to a low pass filter (LPF) 4 which is an anti-aliasing filter of the A / D converter 3, and its output is input to the A / D converter 3 and further to the A / D
The output of the converter 3 is input to the notch filter 5.

The output of the notch filter 5 is input to the phase compensating unit 6 and the phase inverting unit 7 to the disturbance observer 8. The positioning compensation signal output from the phase compensator 6 and the disturbance compensation signal output from the disturbance observer 8 are
The operation signal is added by the adder 9. This operation signal is converted into an analog signal by the D / A converter 10 and then input to the drive circuit 11, and the output of the drive circuit 11 is input to the tracking actuator 12.

The tracking actuator 12 has a finely-coarse integrated structure.
, The force constant is Kf (N / A) and the moving part mass is M
(Kg), the transfer function excluding higher-order resonance is 1 / Ms ² ,
The transfer function of higher resonance is represented by G. The disturbance is represented by D and is applied to the tracking actuator 12. Each component of the notch filter 5, the phase compensating unit 6, the disturbance observer 8, and the phase inverting unit 7 is realized by calculation of a DSP (digital signal processor).

Here, the structure of the fine and coarse integrated tracking actuator 12 will be briefly described.

As shown in FIGS. 2 and 3, the tracking actuator 12 includes a carriage 21 on which a fixed optical system is mounted, Tr coils 22a and 22b for driving the carriage 21 in the track direction, a guide shaft 23a,
23b and magnetic circuits 24a and 24b. The carriage 21 can be driven in the Tr direction by energizing the Tr coils 22a and 22b. Further, the focus actuator 25 includes a holder 27 for fixing the objective lens 26 and the objective lens 26 in the focus direction (z in the figure).
Direction), and leaf coils 28a and 28b that support the tracking lens in a substantially direction, and focus coils 29a and 29b for driving the objective lens 26.
It is mounted on the top of. And the focus coil 2
By energizing 9a and 29b, the focus actuator 25 can be driven in the focus direction. In FIG. 3, reference numeral 30 is a cover.

Next, the configuration of the disturbance observer 8 is shown in FIG. 4, which is an equivalent functional block diagram of the control system of the positioning control apparatus 1 shown in FIG. 1, and the algorithm realized by the DSP is a discrete time system. Expressed as a transfer function. In FIG.
z ⁻¹ is an operator that means a delay of one sample, and the other components are expressed as a continuous-time system transfer function, and the Laplace operator represents s.

Each gain k1, k2, of the disturbance observer 8
G1, G2, L1, L2, and H1 are A / D from the operation signal.
The gain of the same-dimensional observer in the discrete time system created from the transfer function model up to the output of the converter 3, the gain of the drive circuit 11 is Ka (A / V), the sampling period is T (s), and the D / A converter. 10 and the gain of the A / D converter 3 are respectively set to G _DA (V / digit) and G _AD.
(Digit / V), tracking error signal (TE
When the detection sensitivity of S) is K2 (V / m), it is expressed by the following equation.

K1 = Ka k2 = K2 · G _AD G1 = Kf · G _DA · T ² / (2M · k1) G2 = Kf · G _DA · T / (M · k1) L1 = 2 (1-q · cos α ) / K2 L2 = (1 + q ² −2q · cos α) / (T · k2) H1 = −M · L2 / (Kf · T · Ka · G _DA ), where q = exp (−ζωT) α = cos {( [omega] T (1- [zeta] ² ) ^1/2 }, where [omega] and [zeta] represent the estimated speed and damping constant.

Next, the operation of the tracking servo system by the positioning control device 1 of the present embodiment will be described with reference to FIGS. 1, 4, and 5. FIG. 5 is a flowchart showing the algorithm of the calculation performed by the DSP. In the positioning control device 1, as shown in FIG.
Then, the tracking error signal (TE
S) is sampled and converted into a digital signal by the A / D converter 3, the notch filter 5 is calculated in step S2, and then input to the variable Y as a digital position signal (see FIG. 4). Then, in step S3, the output of the notch filter 5 is subjected to calculations such as phase advance compensation in the phase compensator 6 and the positioning compensation signal is input to the variable V.

Next, in step S4, the digital estimated error signal Y _err is calculated by subtracting the digital estimated position signal Yh calculated as described below from the digital position signal Y. Further, in step S5, the digital estimation error signal Y
_The disturbance compensation signal W is generated by multiplying _err by the gain H1.

Then, in step S6, the disturbance compensation signal W is added to the variable V which is the above-mentioned positioning compensation signal to calculate the operation signal U, and in step S7 the operation signal U is converted into an analog signal by the D / A converter 10. It is converted and input to the drive circuit 11. When this output ends, calculation of the digital estimated position signal Yh starts in preparation for the next sample.

First, in step S8, k1 is added to the operation signal U.
The result obtained by multiplying by is input to the variable I. Next, step S9
Then, the calculation X1h = X1h + T · X2h + G1 · I + L1 · Y _err is performed, and in step S10, the calculation X2h = X2h + G2 · I + L2 · Y _err is performed to calculate the digital estimated position signal X1h and the digital estimated speed signal X2h. . Then, the digital estimated position signal X1h calculated in step S11 is multiplied by the gain k1 to calculate the digital estimated position signal Yh (Y
h = k2 · X1h), waiting for the elapse of the sampling period time T (s) in step S12, and when the time T (s) elapses, the process returns to step S1 to sample the next tracking error signal (TES), The DSP repeats the same calculation at the sampling cycle T.

However, the digital estimated position signal X1h and the digital estimated speed X2 on the right side of steps S9 and S10 are set.
h is the value calculated in steps S9 and S10 at the previous sampling, and the digital estimated position signal X1h on the right side of step S11 is calculated in step S9.

In this way, the external force applied to the tracking actuator 12 is estimated and applied to the tracking actuator 12 as a disturbance compensation signal. Therefore, the disturbance is offset.

Further, in this embodiment, since the tracking error signal (TES) as a position signal input to the disturbance observer 8 has passed through the notch filter 5, the frequency component of higher resonance is removed. . Therefore, the disturbance observer 8 operates in a state close to an ideal model having no higher-order resonance, so that the frequency component of the higher-order resonance does not appear in the disturbance compensation signal due to a model error.

Furthermore, a conventional configuration (for example, Japanese Patent Laid-Open No. 5-1)
In Japanese Patent No. 34707), a new notch filter is added, but in the present embodiment, since it is shared with the notch filter of the tracking servo system, the addition of the notch filter does not cause a calculation time delay. Therefore, it is possible to configure a stable head positioning control device for an optical disk device without reducing the gain margin and the phase margin. Further, even when the sampling cycle is shortened in order to suppress the time delay due to the calculation processing, the calculation time does not increase because a new notch filter is not added. For this reason, the calculation processing will not end within the sampling period,
There is no need to lengthen the sampling period or use a faster DSP. Therefore, even if the actuator has a high-order resonance, it is possible to configure a stable head positioning control device for an optical disk device without losing a margin for stability of the servo system or increasing costs.

Further, even if an actuator having a high resonance frequency is structurally used like the actuator of the coarse and coarse type used in the present embodiment, the band of the disturbance observer can be raised stably. Therefore, a cheaper head positioning control device for an optical disk device can be configured.

In the present embodiment, the DSP is used to perform the arithmetic processing, but an ordinary microprocessor may be used as long as the processing time and cost can be allowed.

6 and 7 relate to the second embodiment of the present invention. FIG. 6 is a block diagram showing the configuration of the head positioning control device, and FIG. 7 is an equivalent control system of the positioning control device of FIG. It is a functional block diagram showing various functional blocks.

Since the second embodiment is almost the same as the first embodiment, only different points will be described, the same components will be denoted by the same reference numerals, and description thereof will be omitted.

Head positioning control device 5 of the present embodiment
At 0, as shown in FIG. 6, the tracking error signal detector 2 outputs the position error between the track position and the spot position as a tracking error signal (TES),
The tracking error signal (TES) is input to the disturbance compensator 53 via the phase compensator 51 and the phase inverter 52. The positioning compensation signal which is the output of the phase compensation unit 51 and the disturbance compensation signal which is the output of the disturbance observer 53 are added by the addition unit 9 to become an operation signal. This operation signal is input to the notch filter 54. The output of the notch filter 54 is input to the drive circuit 55, and the output of the drive circuit 55 is input to the tracking actuator 12.

The tracking actuator 12 has a finely-coarse integrated structure, which is similar to that of the first embodiment. Here, the disturbance is represented by D and is applied to the tracking actuator 12. Notch filter 5
4, the phase compensation unit 51, the disturbance observer 53, and the phase inversion unit 52 are realized by, for example, analog circuits in the present embodiment. These can be realized by an integrator using an operational amplifier, an adder, a differential amplifier, and the like.

FIG. 7 shows the positioning control device 5 shown in FIG.
It is an equivalent functional block diagram of the control system of 0. The structure of the disturbance observer 53 is the same as that of FIG. 9 described in the related art, the Laplace operator is represented by s, the detection sensitivity of the tracking error signal (TES) is K2 (V / m),
Transfer function excluding higher-order resonance when the gain of the drive circuit 55 is Ka (A / V), the thrust constant of the tracking actuator 12 is (N / A), and the mass of the movable part mounting the head is M (kg). Is represented by 1 / Ms ² , the transfer function of higher resonance is represented by G, and the disturbance is represented by D (N).

The disturbance observer 53 is a continuous-time same-dimensional observer made from a transfer function model from the operation signal to the spot position without considering higher-order resonance. If the transfer function of the model is G _act , G _act = K1 · K2 / Ms ² .

Gains K1, l1, l2, and H are the gains of the observer of the disturbance and are represented by the following equation.

[0055] When K1 = Ka · Kf l1 = 2ζ · ω / K2 l2 = ω 2 / K2 H = -l2 / K1 the angular frequency of the vibration that you want to suppress ω1, ω is set to a frequency of several times, ζ Is set to 0.5 to 4th place.

The feature of this embodiment is that the notch filter 54 of the tracking servo system is located between the input point of the drive signal of the disturbance observer 53 and the drive circuit 55.

By doing so, the disturbance observer 53
Since the tracking error signal (TES) as the position signal inputted to the signal has passed through the notch filter 54, the frequency component of the high-order resonance is removed.

Therefore, as in the first embodiment,
Since the disturbance observer 53 operates in a state similar to an ideal model without high-order resonance, a high-order resonance frequency component does not appear in the disturbance compensation signal due to a model error.

Further, a conventional structure (for example, Japanese Patent Laid-Open No. 5-13 / 1993) is used.
No. 4707), a new notch filter is added, but in this embodiment, since it is also used as a notch filter of the tracking servo system, the number of parts does not increase due to the addition of the notch filter. . Therefore, there is no increase in cost or the occurrence of problems such as securing a mounting space for newly required parts,
It is possible to configure a stable head positioning control device for an optical disk device that is resistant to disturbance.

[0060]

As described above, according to the head positioning control device for an optical disk device according to the first aspect of the present invention, the disturbance observer receives the output of the notch filter and the input signal of the drive circuit as the disturbance compensation. As the signal is generated, the disturbance observer is operated on the model in which the frequency component of the higher-order resonance of the tracking actuator is removed, the disturbance observer is prevented from being affected by the higher-order resonance, and a new notch filter is added. Even if it is not performed, there is an effect that the estimated band of the disturbance observer can be increased without a higher-order resonance component appearing in the output of the disturbance observer, and stable tracking servo loop characteristics can be obtained without increasing the cost.

Further, according to the head positioning control device of the optical disk device of the second aspect of the present invention, the disturbance observer receives the tracking error signal and the input signal of the notch filter and generates the disturbance compensation signal. ,
The disturbance observer is operated on the model in which the frequency component of the higher-order resonance of the tracking actuator is removed,
Disturbance observer is prevented from being affected by higher resonance,
Even if a new notch filter is not added, the estimated band of the disturbance observer can be increased without the appearance of higher-order resonance components in the output of the disturbance observer, and stable tracking servo loop characteristics can be obtained without increasing the cost. is there.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a head positioning control device according to a first embodiment of the present invention.

FIG. 2 is a first explanatory diagram illustrating a configuration of the tracking actuator of FIG.

FIG. 3 is a second explanatory diagram illustrating the configuration of the tracking actuator of FIG.

FIG. 4 is a functional block diagram showing equivalent functional blocks of a control system of the positioning control device of FIG.

5 is a flowchart illustrating the operation of the positioning control device of FIG.

FIG. 6 is a block diagram showing a configuration of a head positioning control device according to a second embodiment of the present invention.

7 is a functional block diagram showing equivalent functional blocks of a control system of the positioning control device of FIG.

FIG. 8 is a block diagram showing a configuration of a conventional head positioning control device.

9 is a functional block diagram showing equivalent functional blocks of a control system of the positioning control device shown in FIG.

10 is a characteristic diagram showing a frequency characteristic of a gain of "disturbance compensation signal / disturbance" by the positioning control device of FIG.

[Explanation of symbols]

 1 ... Head positioning control device 2 ... Tracking error signal detection unit 2a ... Amplifier 3 ... A / D converter 4 ... LPF 5 ... Notch filter 6 ... Phase compensation unit 7 ... Phase inversion unit 8 ... Disturbance observer 9 ... Addition unit 10 ... D / A converter 11 ... Drive circuit 12 ... Tracking actuator

Claims (3)

[Claims] 1. A tracking actuator for moving the position of a laser beam applied onto an optical disc in a radial direction of the optical disc, and a tracking error signal indicating a positional deviation between the laser beam and an information track on the optical disc are detected. Tracking error signal detection means, a notch filter for removing the frequency component of the higher-order resonance of the tracking actuator that receives the tracking error signal, a phase compensation means that receives the output of the notch filter, and the phase compensation A driving circuit for driving the actuator in accordance with a signal obtained by adding a disturbance compensation signal to the output of the means; and a disturbance observer for receiving the output of the notch filter and the input signal of the driving circuit and generating the disturbance compensation signal. The head position of the optical disk device characterized by Decided controller. 2. A tracking actuator for moving the position of the laser beam irradiated onto the optical disc in the radial direction of the optical disc, and a tracking error signal indicating a positional deviation between the laser beam and the information track on the optical disc are detected. Tracking error signal detecting means, a phase compensating means that receives the tracking error signal, a notch filter that receives a signal obtained by adding a disturbance compensation signal to the output of the phase compensating means, and an actuator according to the output of the notch filter. And a disturbance observer that receives the tracking error signal and the input signal of the notch filter as input, and a disturbance observer that generates the disturbance compensation signal. 3. The tracking actuator includes an objective lens for focusing the laser light, which is mounted on a carriage while being substantially fixed in a direction crossing the track, and which is provided integrally with the carriage. 3. The head positioning control device for an optical disk device according to claim 1, wherein the laser light is configured to be movable so as to irradiate all information tracks on the optical disk by supplying power to a coil.