JP2005317128A - Optical head control device, disk device, optical head control method, and disk processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical head control device for performing sure feed control considering friction quantity of an optical disk, and to provide an optical disk device. <P>SOLUTION: This optical head control device has a transportation part 13 transporting an optical head, a detection part 14 detecting a position of the optical head on the transportation part and outputting a position signal, an estimation part 44 detecting a code of variation of this position signal, estimating friction quantity on the transportation part of the optical head based on this code signal, the position signal, and drive torque, and outputting a friction estimating signal, and a drive part 36 deciding the drive torque based on the position signal from the detection part and the friction estimation signal from the estimation part in accordance with an given movement instruction and supplying it to the estimation part, supplying a drive signal of the optical head in accordance with the drive torque to the transportation part and transporting the optical head. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is a control device for an optical head, and in particular, a control device for an optical head, a disk device, which enables reliable estimation of the friction amount of the optical head by considering the sign of the amount of change in the position signal from the encoder, The present invention relates to an optical head control method and a disk processing method.

  Recently, disk devices such as optical disks have become very popular, and with increasing recording density of disks, for example, high reliability has been demanded in the drive system of optical heads, for example. Here, the optical head can be moved in the radial direction of the disk by a drive motor, and jump processing or the like is performed using this drive system. At this time, a certain amount of friction is generated between the optical head and the transport mechanism, and if the control of the optical head is not performed after sufficiently estimating this friction amount, the control becomes incomplete. For example, an error that could not be controlled is compensated by control by the objective lens actuator. Therefore, when the amount of friction of the optical head cannot be simulated faithfully, the lens orientation deviates from the ideal position by compensating with the objective lens actuator, so that an optical distortion component is generated, and the detection signal is sufficiently transmitted. The signal characteristics cannot be obtained.

  As conventional techniques for controlling the amount of friction, Patent Documents 1 and 2 estimate the amount of friction using a friction force model based on actual measurement values. However, according to this method, there is a problem that a designer or an operator at the time of shipment from the factory has to perform a complicated work of measuring the actual friction amount and storing it in a memory. Furthermore, there is a problem that a memory device or the like must be prepared, which makes it difficult to reduce the size of the device and increases costs.

Patent Document 3 discloses an optical disc apparatus that controls the amount of friction between the optical head and the transport unit. Here, however, a position signal supplied from a coaxial encoder or the like to the drive motor of the transport unit, for example. The amount of friction is estimated based on At this time, for example, when the optical head is finely moved, a phenomenon occurs in which the sign (polarity) of the position signal of the optical head frequently switches from plus to minus and from minus to plus. This phenomenon does not occur when, for example, the optical head is moved greatly to the inner or outer peripheral side of the disk, but the sign (polarity) of this detection signal is used when the optical head starts moving at a minute speed from a stopped state. As a result of this change, it is difficult to estimate the amount of friction particularly at the time of starting, and thus there is a problem that reliable control of the feeding direction of the optical head cannot be performed.
JP-A-9-265748 Japanese Patent Laid-Open No. 9-231701 Japanese Patent Laid-Open No. 8-87751 Iwasaki, Kito, Matsui: "Characteristic analysis and friction compensation of motor speed control system with nonlinearity", IEEJ Transactions D, Vol.116, pp.96-102, (1996-1).

  The present invention generates a friction estimation signal in consideration of the sign of the amount of change in the position signal of the optical head, thereby enabling reliable estimation of the amount of friction even when the optical head is finely moved, thereby enabling reliable optical head feed control. It is an object of the present invention to provide an optical head control device, a disk device, an optical head control method, and a disk processing method.

  The present invention provides a transport unit that transports an optical head, a detection unit that detects a position of the optical head on the transport unit and outputs a position signal, a position signal from the detection unit, An estimation unit that detects a sign of change, estimates a friction amount on the transport unit of the optical head based on the sign signal, the position signal, and a driving torque, and outputs a friction estimation signal; An optical head that determines the driving torque based on a position signal from the detection unit and a friction estimation signal from the estimation unit and supplies the driving torque to the estimation unit in accordance with a movement command that is received. An optical head control device comprising: a drive unit that supplies the drive signal to the transport unit to transport the optical head.

  In the optical head control apparatus described above, the friction amount estimation unit 44 detects the sign of the change in the position signal, and calculates the estimated friction amount of the optical head using the position signal of the optical head in accordance with the change sign. To do. That is, for example, as shown in FIG. 3, the sign of the position signal is detected, and even if this sign is negative, the sign component of the sign function 51 is multiplied by the differential signal or the feedback of the integral signal. Therefore, the signal is always positive. Therefore, in the friction amount estimation unit 44 of the optical head control device according to the present invention, the signal indicating the movement amount according to the position signal of the optical head from the encoder is always negative or positive. It will be treated as a plus signal that is the absolute value of the amount of movement.

  For this reason, the amount of friction is a period in which the sign of the detection signal changes rapidly from plus to minus and minus to plus before and after the optical head starts moving from a stationary state, and the most accurate amount of friction needs to be estimated. In the estimation unit 44, the minus component and the plus component are canceled out, and there is no problem that the amount of friction corresponding to the accurate amount of movement cannot be obtained, and a minute amount corresponding to the degree of movement of the minute optical head is not generated. It is possible to accurately estimate the amount of friction. As a result, it is possible to accurately estimate the amount of friction during the moment when the optical head starts moving from a stationary state. Therefore, as in the conventional device, the error amount must be eliminated by the lens actuator. It is possible to avoid the problem that the lens orientation is not ideal and the optical characteristics deteriorate.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an example of the configuration of an optical disc apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram showing an example of a main part of a control system of the optical disc apparatus according to the embodiment of the present invention. FIG. 4 is a block diagram illustrating an example of a friction amount estimation unit of the optical disc apparatus according to the embodiment of the present invention, and FIG. 4 is a graph illustrating an example of friction torque of the optical head of the optical disc apparatus according to the embodiment of the present invention.

<Optical Disc Device According to Embodiment of the Present Invention>
As shown in FIG. 1, an optical disc apparatus according to an embodiment of the present invention handles an information storage medium D such as an optical disc such as a DVD (Digital Versatile Disc), and the information storage medium D is concentric or A groove is engraved in a spiral shape, and the concave portion of the groove is called a land, the convex portion is called a groove, and one round along the groove is called a track. User data is recorded along this track, and information is reproduced by irradiating the information recording medium D with a laser beam and reading a change in reflected light intensity caused by a recording mark on the track.

  On the other hand, as shown in FIG. 1, the optical disc apparatus according to an embodiment of the present invention includes an optical disc D, a rotary table 31 that holds the optical disc D, and a spindle motor 32 that rotates the rotary table. Further, a spindle motor drive circuit 35 for driving the spindle motor 32 is provided. Further, this optical disc apparatus has an optical head 12 that irradiates the optical disc D with laser light and receives the reflected light, and has an optical head feed mechanism 13 that moves the optical head in the radial direction of the disc. A feed motor drive circuit 36 for driving the optical head feed mechanism 13 is provided.

  Further, this optical disk apparatus includes an objective lens actuator drive circuit 38 for driving the objective lens of the optical head 12, and a focus tracking error for detecting a focus error and a tracking error of the optical head 12, respectively. And a detection circuit 37.

  Further, this optical disc apparatus is binarized by an amplifier 20 for amplifying a detection signal on the optical disc read by the optical head 12, and a binarization circuit 21 for binarizing the output from the amplifier 20. A PLL circuit 22 that receives the output signal, a demodulation circuit 23 that demodulates the output, an error correction circuit 24 that performs error correction on the demodulated signal, and further outputs a signal that has undergone error correction processing to an external device. And a data input / output interface 19 for this purpose. It also has an information recording medium speed detection circuit 34 connected to the PLL circuit 22.

  The optical disk apparatus also has a control unit 30 with a semiconductor memory 25 that controls these operations as a whole. For example, the control unit 30 controls the operation of each unit in accordance with an operation program stored in the semiconductor memory 25.

  Furthermore, the optical disk apparatus is further connected to a data input / output interface 19 as a structure for recording processing, and an ECC encoding circuit 18, a modulation circuit 17, and a control waveform are recorded in order to record information given therefrom. A generation circuit 16 and a semiconductor laser drive circuit 15 for receiving the output and irradiating a semiconductor laser light for appropriate recording are provided, and the laser light corresponding to the semiconductor laser drive circuit 15 is transmitted to the optical head. 12 is irradiated onto the optical disc D to perform recording processing.

(Detailed operation and malfunction)
Furthermore, in the optical disk apparatus according to the embodiment of the present invention, the configuration of each part will be described in more detail, and further, the problems to be solved by the friction amount estimation unit according to the present invention will be described. The optical head moving mechanism (feed motor) 13 moves the optical head 12 for reading information in the radial direction of the information storage medium D described above. Here, the optical head moving mechanism (feed motor) 13 often uses a rod-shaped guide shaft as a guide mechanism for moving the optical head 12, and a space between the guide shaft and a bush attached to a part of the optical head 12. The optical head 12 moves using the friction of the above. In addition, there is a method using a bearing in which frictional force is reduced by using rotational motion.

  Although the detailed shape of the driving force transmission method for moving the optical head 12 is not shown, a rack that is a linear gear that meshes with the pinion by disposing the rotary motor 13 with a pinion (rotating gear) in the fixed system. Is arranged on the side surface of the optical head 12 to convert the rotary motion of the rotary motor into the linear motion of the optical head 12. As another driving force transmission method, there is a case of using a linear motor system in which a permanent magnet is arranged in a fixed system and a current is passed through a coil arranged in the optical head 12 to move in a linear direction.

  In any of the rotation motor and linear motor systems, basically, a current is passed through the feed motor to generate a driving force for moving the optical head 12. This drive current is supplied from the feed motor drive circuit 36.

  When the optical head 12 reaches the target position, the controller 30 issues a command to the objective lens actuator drive circuit 38 to turn on the track servo. The focused spot reproduces the address or track number of the portion while tracing along the track on the information storage medium D.

  The current condensing spot position is calculated from the address or track number there, the number of error tracks from the target position is calculated in the control unit 30, and the number of tracks necessary for the movement of the condensing spot is determined by the objective lens actuator drive circuit 38. Notify

  When one set of kick pulses is generated in the objective lens actuator drive circuit 38, the objective lens slightly moves in the radial direction of the information storage medium D, and the focused spot moves to the adjacent track. In the objective lens actuator drive circuit 38, the track servo is temporarily turned off, the number of kick pulses corresponding to the information from the control unit 30 is generated, and then the track servo is turned on again.

  After the dense access is completed, the control unit 30 reproduces information (address or track number) of the position where the focused spot is traced, and confirms that the target track is being accessed. After confirming that the focused spot has reached the target track by access, a part of the track error detection signal is sent to the optical head drive mechanism (feed motor) 13 via the feed motor drive circuit 36 by a command from the control unit 30. Is supplied as a drive current. This control is continued during the period of continuous reproduction or recording / erasing processing.

  Here, the center position of the information storage medium D is mounted with an eccentricity slightly shifted from the center position of the rotary table 31. When a part of the track error detection signal is supplied as a drive current, the entire optical head 12 finely moves in accordance with the eccentricity.

  Further, when the reproduction or recording / erasing process is continuously performed for a long time, the focused spot position gradually moves in the outer circumferential direction or the inner circumferential direction. When a part of the track error detection signal is supplied as a drive current to the optical head moving mechanism (feed motor) 13, the optical head 12 gradually moves in the outer circumferential direction or the inner circumferential direction in accordance with the driving current. As described above, during continuous reproduction / recording, the smooth fine feed of the optical head 12 reduces the burden of correcting the track deviation of the objective lens actuator.

  As described above, the tracking operation of the optical disk recording / reproducing apparatus moves by a combination of coarse positioning by the pickup head feed system and minute positioning of the objective lens by the lens actuator. The optical system of the pickup head is the optical center of the objective lens. The best reproduction signal can be obtained when it is in the position. Therefore, it is desirable to perform coarse positioning so that the objective lens is always near the optical center position by the lens actuator. However, if the coarse positioning does not move smoothly and stops or goes too far to the desired position, the lens will shift. Since the objective lens must be moved by that amount, the objective lens is displaced from the optical center position, resulting in a deterioration in the state of the reproduced signal.

  In general, coarse positioning by the pickup head feed system 13 is controlled by a PID controller, PI controller, or lag lead type phase compensation controller. As shown in FIG. 4, it is not possible to compensate for the stepwise change in the frictional force due to Coulomb friction when the speed is reversed. Therefore, when the compensation amount becomes too small, the pick-up head feed stops before the desired position, and when the compensation amount becomes too large, a phenomenon occurs in which the pickup head goes too far.

<Drive System of Optical Disc Device According to Embodiment of the Present Invention>
Next, the main part of the drive system of the optical head of the optical disc apparatus according to the embodiment of the present invention will be described in detail with reference to FIG. The main part of the drive system of the optical disk apparatus according to the embodiment of the present invention is that an optical head feed mechanism (feed motor) 13 for driving the optical head 12 has a coaxial rotary encoder 14, and the control unit 30 described above. Inside, the output of the rotary encoder 14 is converted into the angular velocity through the angular velocity converting unit 46 and input to the friction amount estimating unit 44. The friction amount estimation unit 44 is supplied with a drive torque T _{REF obtained} by adding an angular velocity from the angular velocity conversion unit 46 and a friction estimation value described later by an adder, and outputs a friction estimation signal T _FRIC indicating the friction estimation amount to the adder. To do. Further, based on the detection signal from the optical head 12, a tracking error signal is output from the tracking error detection circuit 37, and this output is supplied to the tracking control unit 41 in the control unit 30, and is output from the tracking control unit 41. One of the signals is supplied to the objective lens actuator circuit 38 and the other is supplied to the feed control unit 42. The objective lens actuator drive circuit 38 eliminates the tracking error by driving the objective lens in the optical head 12 with the drive signal.

Further, in the control unit 30, the signal from the angular velocity conversion unit 46 is subtracted from the signal from the feed control unit 42, and the signal output is supplied to the speed control unit 43. In the speed control unit 43, the output is added to the friction estimation signal from the friction amount estimation unit 44, and the torque signal T _REF is supplied to the feed motor drive circuit 36. In the feed motor drive circuit 36, the optical head 12 can be driven in the radial direction of the optical disc by supplying a drive current corresponding to the given torque signal _TREF to the optical head feed mechanism 13.

<Friction amount estimation unit according to an embodiment of the present invention>
In the main part of the drive system of the optical disk apparatus having such a configuration, details of the friction amount estimation unit 44 according to the embodiment of the present invention will be described below with reference to the drawings. That is, in the friction amount estimation unit 44 according to the embodiment of the present invention, an example of the configuration is shown in FIG. 3. Here, the angular velocity given from the angular velocity conversion unit 46 based on the position signal from the rotary encoder 14. The signal ω is acquired and supplied to the sign function 51. The sign function 51 detects the sign of the angular velocity signal ω, and is supplied to the sign function 51 accordingly, for example. In response, for example, “+1” or “−1” is supplied to the multiplier 55 and the multiplier 56.

On the other hand, the angular velocity signal ω given from the angular velocity converting unit 46 is differentiated with respect to time by the differentiator 52, and the differential signal output is supplied to the subtractor 53 together with the driving torque T _REF. To be supplied. The adder 54 is _supplied with a friction estimation signal in which the friction estimation signal indicating the friction estimation value T _FRIC obtained by the friction amount estimation unit 44 becomes a positive signal through the multiplier 56. Then, the result of the subtraction operation of the subtractor 54 is supplied to the multiplier 55, and here again the operation result is always a positive signal according to the sign information and supplied to the time integrator 57. Thus, in the control unit 30, the absolute value of the estimated friction value is processed.

On the other hand, the time integrator 57 outputs a friction estimation signal corresponding to the estimated friction value T _FRIC to be obtained by integrating the output of the multiplier 55 with respect to time. After that, by multiplying the friction estimation signal corresponding to the friction estimation value T _FRIC by the sign signal “+1” or “−1” from the sign function 51 in the multiplier 58, the original sign (polarity of the signal) ) Is restored to the original state, and the control direction is made appropriate.

  That is, the friction amount estimation unit 44 according to the present invention further applies the nonlinear disturbance observer shown in Non-Patent Document 1 described above to compensate for the frictional force. Smooth feed control of the optical head is possible.

  In other words, the friction torque estimator using a conventional general disturbance observer is affected by the time constant of its own integrator, for example, the rotation of the motor that appears when the optical head starts moving from a stationary state. Unable to follow the change in the stepped Coulomb friction (see Fig. 4) in accordance with the change in direction, the angular velocity ω changes, for example, the signal sign (polarity) rapidly, and the absolute amount of actual movement It is not possible to accurately estimate the amount of friction according to.

  However, in the friction torque estimation method using the method shown in Non-Patent Document 1, the change in the stepwise coulomb friction is obtained by estimating the friction torque by inverting the sign (polarity) of the calculation by the change in the rotation direction. It is possible to estimate the estimated value of the friction torque following the above.

  That is, to put it simply, when the angular velocity signal ω takes a positive value or a negative value in the friction amount estimation unit 44, the output of the sign function 51 corresponding to this takes place each time. It takes values of “+1”, “−1”, etc., and this output is multiplied by the multipliers 55 and 56, so that the output of the multiplier 55 and the output of the multiplier 56 are always positive. Become. As a result, in the signal processing of the friction amount estimation unit that outputs the friction estimation signal according to the friction estimation value according to the value of the angular velocity ω, there is no signal that takes a negative value, so the absolute value of the signal change is used. Equivalent to performing arithmetic processing. As a result, even if the sign of the angular velocity signal ω changes rapidly, processing regarding the absolute value of the amount of movement of the optical head 12 is always performed, so that the estimated friction amount of the optical head 12 can be accurately estimated. Is.

Further, the outline of the function of each part of the friction amount estimating unit 44 will be described. First, the angular velocity ω from the angular velocity converting unit 46 is received, and the sign function 51 detects the sign of the angular velocity ω and detects the sign signal. In the differentiator 52, the angular velocity ω is time-differentiated and a differential signal is output, and in the subtractor 53, a difference signal is obtained by _obtaining a difference between the differential signal and the driving torque T _REF corresponding to the movement command. The multiplier 56 multiplies the friction estimation signal T _FRIC by the sign signal, the subtractor 54 subtracts the signal obtained by multiplying the friction estimation signal T _FRIC by the sign signal from the difference signal, and the multiplier 55 Is obtained by multiplying the signal obtained by subtracting the friction estimation signal from the difference signal by the sign signal, and further integrating the output of the multiplier 55 with time in the integrator 57, so that the friction corresponding to the friction estimation value T _FRIC is obtained. The friction estimation signal is obtained.

(Details of friction amount estimation unit 44)
Next, details of the friction amount estimation unit 44 according to an embodiment of the present invention will be described with reference to the drawings.

  First, the control unit 30 in FIG. 1 controls drive parts such as the focus, tracking, and tilt actuators of the optical head 12, the spindle motor 32, and the pickup head feed motor 13, and the drive circuits 35, 36, and 38. This is the part that gives the command value to FIG. 2 is a block diagram showing the main part of the pick-up feed control of the optical disk recording / reproducing apparatus from the control unit 30 in FIG. 1, and determines the motor drive command value from the speed command value and the actually measured speed value, and the feed motor drive circuit. The command value is transmitted to 36.

  FIG. 3 shows details of the friction amount estimation unit 44. Further, the actual speed of the optical head 12 or the head feed mechanism 13 can be detected by the speed detector using the rotary encoder 14 of FIG. Here, the difference between the speed command value and the actually measured speed value is input, and the output torque is determined by the PID controller, PI controller, or lag lead type speed control unit 43. At the same time, the actually measured speed value is converted into the angular velocity ω through the angular velocity converting unit 46 and input to the friction amount estimating unit 44.

Further, as shown in FIG. 3, the friction amount estimation unit 44 performs an operation using the angular velocity ω and the driving torque T _REF from the speed control unit 43 after addition of the friction torque as inputs, and performs friction according to the estimated friction value T _FRIC. An estimated signal is calculated. Actually, the actual rotational torque T _MTR is calculated by multiplying the differential value of the rotational angular velocity ω of the feed motor by the inertia J, and the difference from the drive torque is estimated as the estimated friction value T _FRIC .

Here, assuming that the motor rotational torque _TMTR is an angular velocity ω and an inertia J,
T _MTR = J _ωs
It can be expressed as.

The magnitude of the estimated friction value T _FRIC is calculated using the sign function sgn (ω) of the average value T _REF of the drive torque, the motor rotational torque T _MTR , the time constant τ, and ω,

It can be expressed as. Here, the sign function sgn (ω) is

Or, in order to prevent an oscillation state due to the influence of noise or the like near the speed 0, the sign function uses an appropriate speed threshold th when th = 0.

When th ≠ 0

It is also conceivable to reduce the influence of the range of | ω | <| th |.

In particular, in a speed detector with a large observation noise, the following may be used as the sgn function for the friction amount estimation unit 44.

In the friction amount estimation unit 44, even when the sign of the speed is suddenly reversed such as positive → negative (negative → positive), the magnitude of the friction torque T _FRIC is always appropriate by inverting the sign at the stage of calculation. Can be estimated. As a compensation value output from the friction amount estimation unit 44, an appropriate value capable of compensating the friction even when the friction changes stepwise from the speed 0 by multiplying a sign corresponding to the speed direction as follows. Compensation values can be added in any direction.

T _FRIC = sgn (ω) × | T _FRIC |
The final command value _{T OUT} is obtained by adding the friction torque _{T Fric} estimated friction quantity estimating section 44 to the output torque _{T R} from the speed control unit 43.

In the above equation for calculating the estimated friction torque T _FRIC , the sign of the speed command value is used as an argument of the sign function sgn function instead of the sign of the rotational angular speed ω actually measured, so that the observation noise of the speed sensor can be reduced. The problem may be alleviated.

T _OUT = T _R + T _FRIC
The command value is transmitted to the feed motor drive circuit 36, and the feed motor drive circuit 36 causes the drive current to flow through the feed motor 13 to drive the optical head 12.

  As described above, compensation of the friction torque by the friction amount estimation unit 44 enables smooth pickup head positioning especially when the optical head is started from a stationary state, and accordingly, the track deviation correction of the objective lens actuator is performed. An optical head control device, a disk device, an optical head control method, and a disk processing method are provided.

  With the various embodiments described above, those skilled in the art can realize the present invention. However, it is easy for those skilled in the art to come up with various modifications of these embodiments, and have the inventive ability. It is possible to apply to various embodiments at least. Therefore, the present invention covers a wide range consistent with the disclosed principle and novel features, and is not limited to the above-described embodiments.

1 is a block diagram showing an example of the configuration of an optical disc device according to an embodiment of the present invention. 1 is a block diagram showing an example of a main part of a control system of an optical disc apparatus according to an embodiment of the present invention. The block diagram which shows an example of the frictional amount estimation part of the optical disk apparatus of embodiment which concerns on this invention. 6 is a graph showing an example of friction torque of the optical head of the optical disc apparatus according to the embodiment of the present invention.

Explanation of symbols

  51: Sign function, 52: Differentiator, 53: Subtractor, 54: Subtractor, 55, 56: Multiplier, 57: Integrator.

Claims (20)

A transport unit for transporting the optical head;
A detection unit that detects a position of the optical head on the transport unit and outputs a position signal;
The position signal from the detection unit is received, the sign of the change in the position signal is detected, and the amount of friction on the transport unit of the optical head based on the sign signal, the position signal, and the driving torque An estimation unit that estimates the friction and outputs a friction estimation signal;
In accordance with a given movement command, the driving torque is determined based on the position signal from the detection unit and the friction estimation signal from the estimation unit, and is supplied to the estimation unit. An optical head control apparatus comprising: a drive for supplying the head drive signal to the transport unit to transport the optical head.   The optical head control device according to claim 1, wherein the detection unit uses a coaxial encoder as a motor of the transport unit, and an angular velocity signal based on a continuous position signal from the encoder is output.   The estimation unit, when obtaining the friction estimation signal, detects a sign of the change amount of the position signal and outputs a sign signal, and uses the sign signal to calculate the position signal from the detection unit. 2. The friction estimation signal corresponding to the absolute amount of change in the position signal is output without being affected by a change in the sign of the change amount in the position signal. Optical head control device. The estimation unit includes
Detecting the sign of the position signal and outputting the sign signal;
Time derivative of the position signal from the detection unit to output a differential signal,
Find the difference between the differential signal and the drive torque according to the movement command, and output a difference signal,
Multiplying the friction estimation signal by the sign signal;
Subtract the signal obtained by multiplying the friction estimation signal by the sign signal from the difference signal,
2. The optical head control apparatus according to claim 1, wherein the friction estimation signal is obtained by multiplying the signal obtained by subtracting the friction estimation signal from the difference signal by the sign signal and further integrating the signal with time. . A detection unit that receives a detection signal based on the reflected light of the laser beam irradiated on the recording medium from the detection unit of the optical head, and generates a tracking error signal based on the detection signal;
The drive unit includes a feed control unit that generates the drive signal and supplies the drive signal to the transport unit in order to command the movement of the optical head to eliminate the tracking error signal. 2. The optical head control device according to 1. A transport unit for transporting the optical head;
A detection unit that detects a position of the optical head on the transport unit and outputs a position signal;
The position signal from the detection unit is received, the sign of the change in the position signal is detected, and the amount of friction on the transport unit of the optical head based on the sign signal, the position signal, and the driving torque An estimation unit that estimates the friction and outputs a friction estimation signal;
In accordance with a given movement command, the driving torque is determined based on the position signal from the detection unit and the friction estimation signal from the estimation unit, and is supplied to the estimation unit. A drive unit that feeds a drive signal of the head to the transport unit to transport the optical head;
The optical head transported by the driving unit by the driving unit receives reflected light of the laser light irradiated on the disk, performs reproduction processing based on the reflected light, and laser light corresponding to information to be recorded A processing unit that generates a driving signal, supplies the optical head to the optical head, and performs recording processing by irradiating the disk with laser light corresponding to information to be recorded;
A disk device comprising:   The disk device according to claim 6, wherein the detection unit uses a coaxial encoder for the motor of the transport unit, and an angular velocity signal based on a continuous position signal from the encoder is output.   The estimation unit, when obtaining the friction estimation signal, detects a sign of the change amount of the position signal and outputs a sign signal, and uses the sign signal to calculate the position signal from the detection unit. 7. The friction estimation signal corresponding to the absolute amount of the change in the position signal is output without being affected by the change in the sign of the change amount in the position signal. Disk unit. The estimation unit includes
Detecting the sign of the position signal and outputting the sign signal;
Time derivative of the position signal from the detection unit to output a differential signal,
Find the difference between the differential signal and the drive torque according to the movement command, and output a difference signal,
Multiplying the friction estimation signal by the sign signal;
Subtract the signal obtained by multiplying the friction estimation signal by the sign signal from the difference signal,
7. The disk apparatus according to claim 6, wherein the friction estimation signal is obtained by multiplying the signal obtained by subtracting the friction estimation signal from the difference signal by the sign signal and further integrating the signal with time. A detection unit that receives a detection signal based on the reflected light of the laser beam irradiated on the disk from the detection unit in the optical head, and generates a tracking error signal based on the detection signal;
The drive unit includes a feed control unit that generates the drive signal and supplies the drive signal to the transport unit in order to command the movement of the optical head to eliminate the tracking error signal. 6. The disk device according to 6. Detect the position on the transport part of the optical head and output a position signal,
Receiving the position signal, detecting a sign of a change in the position signal, estimating a friction amount of the optical head based on the sign signal, the position signal, and a driving torque, and outputting a friction estimation signal;
In response to a given movement command, the driving torque is determined based on the position signal and the friction estimation signal, and an optical head driving signal corresponding to the driving torque is supplied to transport the optical head. An optical head control method characterized by the above.   12. The optical head control method according to claim 11, wherein the position signal is detected by outputting an angular velocity signal based on a continuous position signal from a coaxial k encoder to a motor for transporting the optical head.   When generating the friction estimation signal, the sign of the change amount of the position signal is detected by detecting the sign of the change amount of the position signal and outputting the sign signal, and calculating the position signal using this sign signal. 12. The optical head control method according to claim 11, wherein the friction estimation signal corresponding to the absolute amount of the change of the position signal is output without being affected by the change even if it changes. Detecting the sign of the position signal and outputting the sign signal;
The position signal is time-differentiated and a differential signal is output,
Find the difference between the differential signal and the drive torque according to the movement command, output the difference signal, multiply the friction estimation signal by the sign signal,
Subtract the signal obtained by multiplying the friction estimation signal by the sign signal from the difference signal,
12. The optical head control method according to claim 11, wherein the friction estimation signal is obtained by multiplying the signal obtained by subtracting the friction estimation signal from the difference signal by the sign signal and further integrating the signal with time. . Receiving a detection signal based on the reflected light of the laser beam applied to the recording medium from the optical head, and generating a tracking error signal based on the detection signal;
12. The optical head control method according to claim 11, wherein the drive signal is generated so as to eliminate the tracking error signal, and the optical head is moved in response thereto. Detect the position on the transport part of the optical head and output a position signal,
Receiving the position signal, detecting a sign of a change in the position signal, estimating a friction amount of the optical head based on the sign signal, the position signal, and a driving torque, and outputting a friction estimation signal;
In response to a given movement command, the driving torque is determined based on the position signal and the friction estimation signal, and an optical head driving signal corresponding to the driving torque is supplied to transport the optical head,
The optical head receives the reflected light of the laser light applied to the disk by the optical head, performs reproduction processing based on the reflected light, and generates a laser light driving signal corresponding to information to be recorded to generate the optical light. A disk processing method characterized in that a recording process is performed by irradiating the disk with a laser beam according to information to be recorded by being supplied to a head.   The detection of the position signal uses a coaxial encoder as a motor for transporting the optical head, and outputs an angular velocity signal based on a continuous position signal from the encoder. Disk processing method.   When generating the friction estimation signal, the sign of the change amount of the position signal is detected by detecting the sign of the change amount of the position signal and outputting the sign signal, and calculating the position signal using this sign signal. 17. The disk processing method according to claim 16, wherein the friction estimation signal corresponding to the absolute amount of the change in the position signal is output without being influenced by the change even if it changes. Detecting the sign of the position signal and outputting the sign signal;
The position signal is time-differentiated and a differential signal is output,
Find the difference between the differential signal and the drive torque according to the movement command, and output a difference signal,
Multiplying the friction estimation signal by the sign signal;
Subtract the signal obtained by multiplying the friction estimation signal by the sign signal from the difference signal,
17. The disk processing method according to claim 16, wherein the friction estimation signal is obtained by multiplying the signal obtained by subtracting the friction estimation signal from the difference signal by the sign signal and further integrating the signal with time. Receiving a detection signal based on the reflected light of the laser beam applied to the recording medium from the optical head, and generating a tracking error signal based on the detection signal;
17. The disk processing method according to claim 16, wherein the drive signal is generated so as to eliminate the tracking error signal, and the optical head is moved in response thereto.

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