JP4024195B2 - Disk device and control method thereof - Google Patents

Description

  The present invention relates to a disk device that positions a recording / reproducing head to a target track of a disk as a recording medium with high accuracy by an actuator. More specifically, the present invention relates to a technique for suppressing the head from deviating from a target track due to a disturbance received by an actuator.

  The present invention also provides a disk device having a load / unload mechanism that unloads the head onto a head retracting member such as a ramp block outside the disk when stopped, and loads the head onto the disk surface from the head retracting member during use. The present invention relates to a technique for stably loading a head onto a disk surface under appropriate speed control even when a disturbance on the head retracting member is large.

  In recent years, disk devices such as magnetic disk devices have been rapidly reduced in size and capacity, and there has been a trend toward higher track density and narrower track pitch, and high-precision positioning of the head with respect to the target track has become important. Yes. The head reads servo information recorded in advance on the disk, generates a head position error signal with respect to the target track, and controls the head positioning so that the magnitude of the position error signal is minimized. In order to increase the positioning speed, the control frequency of the positioning control system may be increased. However, the positioning control system becomes unstable due to the inherent mechanical resonance of the head actuator. Under such circumstances, there is a limit to increasing the control frequency.

As the track density is increased and the track pitch is reduced and the actuator is reduced in size and weight, the influence of the disturbance acting on the actuator on the positioning control system increases. On the other hand, the demand for high-precision positioning of the head is severe. It is important to reduce disturbance that is a cause of deterioration in head positioning accuracy. Conventionally, a technique has been proposed in which disturbance is estimated based on a head position signal obtained from servo information on a disk and an actuator drive signal, and the disturbance is compensated by feedforward control (see, for example, Patent Document 1). ).
Japanese Patent Laid-Open No. 9-231701 (page 4-5, FIG. 1)

  However, the servo information on the disk is discrete information having a constant sampling period, and the head position signal reproduced from this is not a continuous signal. Due to the restriction of the sampling frequency of servo information, there is an upper limit in the control band of the disturbance estimation means, and the presence of this upper limit makes it difficult to accurately estimate the disturbance. As a result, it is difficult to make the head always follow the target track accurately.

  The present invention has been made to solve the above-described problems, and accurately estimates the disturbance acting on the actuator means by the disturbance estimation means and satisfactorily cancels the disturbance, thereby improving the head positioning accuracy with respect to the target track. The purpose is to improve.

  Further, since the fluctuation of the disturbance due to the sliding friction is large on the head retracting member, the head slider speed fluctuates greatly. Even if feedback control of the head slider moving speed is performed, the fluctuation of the head loading speed is large and the slider may collide with the disk.

  Accordingly, an object of the present invention is to provide a disk device capable of stable speed control by compensating for an external force such as friction acting on an actuator, even if the fluctuation of the disturbance on the head retracting member is large. .

  In order to cancel disturbances such as bearing friction and elastic force applied to the actuator means and inertial forces caused by impact and vibration, the magnitude of the disturbance is estimated. Two factors are used in estimating the magnitude of the disturbance. One is to detect a voltage generated in driving the actuator means and use a voltage signal as a result of the detection. The other is a drive signal in the drive means of the actuator means. Here, the drive signal in the drive unit may be input to the drive unit or may be output from the drive unit. Further, instead of the drive signal in the drive means, a position control signal that generates the drive signal may be used. That is, a disturbance estimation means for estimating the magnitude of the disturbance is provided, and with this disturbance estimation means, the voltage signal detected by the voltage detection means and the drive signal or position control signal in the drive means are input, and the disturbance estimation signal is Generate. The disturbance estimation signal generated based on the two elements is an accurate estimate of the magnitude of the disturbance actually applied to the head. As a result, the amount of disturbance such as the bearing friction of the actuator means, the elastic force of the FPC (flexible printed circuit) connecting the actuator means and the electronic circuit board, and the inertial force received by the actuator means due to external impact or vibration on the disk device. Can be estimated accurately.

  In the correction means, the disturbance estimation signal is combined with the position control signal from the position control means to generate a drive signal so as to cancel the disturbance applied to the actuator means with the disturbance estimation signal accurately estimated as described above. By driving the actuator means of the head using the drive signal, disturbances such as bearing friction, elastic force and inertial force applied to the actuator means can be canceled and compensation for the disturbance can be satisfactorily performed.

  The present invention is not limited to the above, but goes further and considers the following points.

  The disturbance estimation unit generates a voltage estimation signal corresponding to the input voltage signal, compares the voltage estimation signal with the input voltage signal, and generates a difference deviation signal. Further, an integral signal obtained by integrating the deviation signal and a proportional signal proportional to the deviation signal are generated, and an addition signal of the integral signal and the proportional signal is fed back to generate the voltage estimation signal, so that the deviation signal approaches zero. .

  Here, as a basic idea, there is an idea that a disturbance estimation signal is generated based only on the integrated signal with respect to generation of the disturbance estimation signal to be returned to the correcting means. Even when the disturbance estimation signal is generated based only on the integral signal, if the actuator means is driven by a drive signal obtained by synthesizing the disturbance estimation signal and the position control signal, the above-described effect is exhibited and compensation for the disturbance is performed. I can.

  However, when the disturbance estimation signal is generated based only on the integral signal, a phase difference occurs between the disturbance estimation signal and the actual disturbance, and the disturbance estimation signal causes a phase lag with respect to the actual disturbance. If the actuator means is driven by a drive signal based on a disturbance estimation signal including a phase delay, the effect of compensation for the disturbance is exhibited, but there is still an influence of the phase delay. There is room for improvement here, and the present invention is further advanced to add the following means in order to perform sufficient compensation.

That is, the disturbance estimation means adds the integral signal of the deviation signal and the proportional signal of the deviation signal at a constant ratio to generate a disturbance estimation signal. The disturbance estimation signal τdest can be expressed as [τdest = k ₁ · a + k ₂ · b], where a is the integral signal, b is the proportional signal, and k ₁ and k ₂ are both non-zero coefficients. The proportional signal has a phase advanced by 90 degrees with respect to the integral signal (see, for example, FIG. 7). Therefore, the phase delay can be reduced by appropriately combining the integral signal and the proportional signal. That is, it is possible to generate a disturbance estimation signal that is closer to the actual disturbance. The disturbance estimation signal in which the phase lag is suppressed is combined with the position control signal in the correction means, and the actuator means is driven by the obtained drive signal, so that the bearing friction, the elastic force, the inertial force, etc. acting on the actuator means are reduced. Compensation for disturbance can be sufficiently satisfactorily performed. As a result, it is possible to stably control the positioning of the head to the target track even if the fluctuation of the disturbance acting on the actuator means during the following operation toward the target track is large. In addition, as a secondary effect, the track density can be substantially improved, and the realization of a large capacity disk device can be promoted.

  Hereinafter, the present invention described above will be described at a more specific level.

As a first solution, the disk device according to the present invention includes a plurality of components as follows. That is,
Actuator means for positioning the head relative to the disk;
Driving means for the actuator means;
Voltage detection means for detecting a voltage generated in driving the actuator means and outputting a voltage signal;
Disturbance estimation means for estimating the magnitude of disturbance applied to the head from the drive signal and the voltage signal in the drive means, and generating a disturbance estimation signal;
Position detecting means for generating a position error signal corresponding to the current position of the head from servo information recorded in advance on the disk and detected by the head;
Position control means for generating a position control signal corresponding to the position error signal;
And correction means for synthesizing the drive signal from the position control signal and the disturbance estimation signal.

Further, the disturbance estimation means includes:
A comparison means for comparing the voltage estimation signal generated by the disturbance estimation means with the voltage signal and outputting a deviation signal;
Adding means for adding the signal obtained by multiplying the integral signal obtained by integrating the deviation signal by the first coefficient and the signal obtained by multiplying the proportional signal proportional to the deviation signal by the second coefficient to generate the disturbance estimation signal; I have.

  In this configuration, the drive signal in the drive means may be input to the drive means or may be output from the drive means, and this is the same in the following.

The operation of the first solving means is as follows. The disturbance estimation means applies a disturbance applied to the actuator means (bearing friction, elastic force of the FPC connected to the electronic circuit board, externally applied) based on the drive signal applied to the drive means of the actuator means and the voltage signal detected from the actuator means. Estimate the magnitude of the inertia force caused by shock or vibration). Here, the disturbance estimation signal is not generated based only on the integration signal of the deviation signal, which is the difference between the voltage estimation signal and the voltage signal, but the integration signal and the proportional signal are kept constant by using the proportional signal of the deviation signal. To generate a disturbance estimation signal [τdest = k ₁ · a + k ₂ · b]. Thereby, the phase delay of the disturbance estimation signal with respect to the actual disturbance can be reduced, and the disturbance estimation signal in a state closer to the actual disturbance can be generated. The disturbance estimation signal is combined with the position control signal to generate a drive signal so as to cancel the disturbance applied to the actuator means with the accurately estimated disturbance estimation signal with the phase delay suppressed. By driving the actuator means of the head with the drive signal, the disturbance applied to the actuator means can be canceled and compensation for the disturbance can be satisfactorily performed, so even if the fluctuation of the disturbance is large during the following operation toward the target track, Positioning control of the head to the target track can be stably performed.

The first solving means is described as a disk device control method as follows. That is,
A position error signal corresponding to the current position of the head is generated from servo information recorded in advance on the disk and detected by the head,
Generating a position control signal corresponding to the position error signal;
Generating a voltage estimation signal that is an estimation of the voltage signal based on a drive signal of the actuator means for positioning the head and a voltage signal generated in driving the actuator means;
Comparing the voltage estimation signal and the voltage signal to generate a deviation signal of the difference,
A disturbance estimation signal is generated by adding a signal obtained by multiplying the integral signal obtained by integrating the deviation signal by a first coefficient and a signal obtained by multiplying a proportional signal proportional to the deviation signal by a second coefficient;
The position control signal and the disturbance estimation signal are combined to generate the drive signal,
The actuator means is driven by the drive signal to position the head with respect to the disk.

  According to this disk device control method, the same effect as described above is exhibited.

As a second solution, the disk device according to the present invention includes the following plural components. That is,
Actuator means for positioning the head relative to the disk;
Driving means for the actuator means;
Voltage detection means for detecting a voltage generated in driving the actuator means and outputting a voltage signal;
Disturbance estimation means for estimating the magnitude of disturbance applied to the head from the drive signal and the voltage signal in the drive means, and generating a disturbance estimation signal;
Position detecting means for generating a position error signal corresponding to the current position of the head from servo information recorded in advance on the disk and detected by the head;
Position control means for generating a position control signal corresponding to the position error signal;
And correction means for synthesizing the drive signal from the position control signal and the disturbance estimation signal.

Further, the disturbance estimation means includes:
A comparison means for comparing the voltage estimation signal generated by the disturbance estimation means with the voltage signal and outputting a deviation signal;
Filter means for cutting off a high frequency component of a proportional signal proportional to the deviation signal and generating a filter output signal;
And adding means for adding the signal obtained by multiplying the integral signal obtained by integrating the deviation signal by the first coefficient and the signal obtained by multiplying the filter output signal by the second coefficient to generate the disturbance estimation signal.

  The operation of the second solving means is basically the same as that of the first solving means. And noise can be reduced by adding the filter means to the disturbance estimating means. The filter means generates a filter output signal by cutting off a high frequency component of the proportional signal. On the other hand, the high frequency component of the integrated signal is cut off in the process of integrating the deviation signal. This is because the integration itself is a kind of high-frequency cutoff filter. Therefore, the disturbance estimation signal obtained by synthesizing the integration signal and the filter output signal is a signal with less noise from which high-frequency components are removed. Further, the stability of the entire control system can be improved when the disturbance estimation means is applied to the positioning control system.

The second solving means is described as a disk device control method as follows. That is,
A position error signal corresponding to the current position of the head is generated from servo information recorded in advance on the disk and detected by the head,
Generating a position control signal corresponding to the position error signal;
Generating a voltage estimation signal that is an estimation of the voltage signal based on a drive signal of the actuator means for positioning the head and a voltage signal generated in driving the actuator means;
Comparing the voltage estimation signal and the voltage signal to generate a deviation signal of the difference,
A signal obtained by multiplying the integral signal obtained by integrating the deviation signal by the first coefficient and a filter output signal obtained by blocking the high frequency component of the proportional signal proportional to the deviation signal are added to the signal multiplied by the second coefficient. To generate a disturbance estimation signal,
The position control signal and the disturbance estimation signal are combined to generate the drive signal,
The actuator means is driven by the drive signal to position the head with respect to the disk.

  According to this disk device control method, the same effect as described above is exhibited.

In the first or second solving means described above, it is preferable to configure as follows. That is,
Comparing means for inputting the voltage signal detected by the voltage detecting means for the configuration of the disturbance estimating means,
First multiplication means for multiplying the drive signal by a coefficient comprising a first transfer function;
Second multiplication means for multiplying the output of the comparison means by a coefficient comprising a second transfer function;
First integrating means for integrating the output of the comparing means;
And a second integration unit that integrates a value obtained by subtracting an addition value of the output of the second multiplication unit and the output of the first integration unit from the output of the first multiplication unit.

  Further, the comparison means compares the output of the second integration means with the voltage signal and outputs the difference to the second multiplication means and the first integration means.

  The effect | action by this structure is as follows. The output of the first multiplication means for inputting the drive signal is a drive torque estimation signal corresponding to the drive torque acting on the actuator means. The output of the second integration means is a voltage estimation signal for the voltage signal detected by the voltage detection means. The deviation signal output from the comparison means that takes the difference between the voltage estimation signal from the second integration means and the voltage signal is provided to the first integration means and the second multiplication means. The addition value of the output of the second multiplication means and the output of the first integration means is subtracted from the output of the first multiplication means and provided to the second integration means. A signal obtained by adding an integral signal obtained by integrating the deviation signal and a proportional signal proportional to the deviation signal at a constant ratio is a disturbance estimation signal.

  As a result of the above, the generated disturbance estimation signal corresponds to an accurate estimation of the disturbance received by the actuator means. Since feedforward control is performed to cancel the disturbance with the disturbance estimation signal accurately determined in this way, it is possible to satisfactorily compensate for the disturbance in the following operation, even if the fluctuation of the disturbance is large during the following operation. Therefore, the head positioning control with respect to the target track can be stably performed, and the positioning accuracy can be improved.

As a third solution, the disk device according to the present invention includes a plurality of components as follows. That is,
Actuator means for positioning the head relative to the disk;
Driving means for the actuator means;
Voltage detection means for detecting a voltage generated in driving the actuator means and outputting a voltage signal;
Position detecting means for generating a position error signal corresponding to the current position of the head from servo information recorded in advance on the disk and detected by the head;
Position control means for generating a position control signal corresponding to the position error signal;
Disturbance estimation means for estimating a magnitude of disturbance applied to the head from the position control signal and the voltage signal and generating a disturbance estimation signal;
And correction means for synthesizing the drive signal from the position control signal and the disturbance estimation signal.

Further, the disturbance estimation means includes:
A comparison means for comparing the voltage estimation signal generated by the disturbance estimation means with the voltage signal and outputting a deviation signal;
Adding means for adding the signal obtained by multiplying the integral signal obtained by integrating the deviation signal by the first coefficient and the signal obtained by multiplying the proportional signal proportional to the deviation signal by the second coefficient to generate the disturbance estimation signal; I have.

The operation of the third solving means is as follows. The elements input to the disturbance estimating means are the voltage signal and the drive signal in the first solving means, whereas in this solving means, the voltage signal and the position control signal are input to the disturbance estimating means. The disturbance estimation means accurately estimates the magnitude of the disturbance received by the actuator means based on the position control signal from the position control means and the voltage signal detected from the actuator means. Here, the disturbance estimation signal is not generated based only on the integration signal of the deviation signal, which is the difference between the voltage estimation signal and the voltage signal, but the integration signal and the proportional signal are kept constant by using the proportional signal of the deviation signal. To generate a disturbance estimation signal [τdest = k ₁ · a + k ₂ · b]. Thereby, the phase delay of the disturbance estimation signal with respect to the actual disturbance can be reduced, and the disturbance estimation signal in a state closer to the actual disturbance can be generated. The disturbance estimation signal is combined with the position control signal output from the position control means to generate a drive signal so as to cancel the disturbance with the accurately estimated disturbance estimation signal with the phase delay suppressed. By driving the actuator means of the head with the drive signal, the disturbance can be canceled out and the compensation for the disturbance can be satisfactorily performed, so even if the fluctuation of the disturbance during the following operation toward the target track is large, the target track of the head Can be stably controlled.

The third solution can be described as a disk device control method as follows. That is,
A position error signal corresponding to the current position of the head is generated from servo information recorded in advance on the disk and detected by the head,
Generating a position control signal corresponding to the position error signal;
Generating a voltage estimation signal that is an estimate of the voltage signal from the position control signal and a voltage signal generated in driving the actuator means;
Comparing the voltage estimation signal and the voltage signal to generate a deviation signal of the difference,
A disturbance estimation signal is generated by adding a signal obtained by multiplying the integral signal obtained by integrating the deviation signal by a first coefficient and a signal obtained by multiplying a proportional signal proportional to the deviation signal by a second coefficient;
The position control signal and the disturbance estimation signal are combined to generate the drive signal,
The actuator means is driven by the drive signal to position the head with respect to the disk.

  According to this disk device control method, the same effect as described above is exhibited.

As a fourth solution, the disk device according to the invention comprises an actuator means for positioning the head with respect to the disk;
Driving means for the actuator means;
Voltage detection means for detecting a voltage generated in driving the actuator means and outputting a voltage signal;
Position detecting means for generating a position error signal corresponding to the current position of the head from servo information recorded in advance on the disk and detected by the head;
Position control means for generating a position control signal corresponding to the position error signal;
Disturbance estimation means for estimating a magnitude of disturbance applied to the head from the position control signal and the voltage signal and generating a disturbance estimation signal;
And correction means for synthesizing the drive signal from the position control signal and the disturbance estimation signal.

Further, the disturbance estimation means includes:
A comparison means for comparing the voltage estimation signal generated by the disturbance estimation means with the voltage signal and outputting a deviation signal;
Filter means for cutting off a high frequency component of a proportional signal proportional to the deviation signal and generating a filter output signal;
And adding means for adding the signal obtained by multiplying the integral signal obtained by integrating the deviation signal by the first coefficient and the signal obtained by multiplying the filter output signal by the second coefficient to generate the disturbance estimation signal.

  The operation of the fourth solving means is basically the same as that of the third solving means. And noise can be reduced by adding the filter means to the disturbance estimating means. The filter means generates a filter output signal by cutting off a high frequency component of the proportional signal. On the other hand, the high frequency component of the integrated signal is cut off in the process of integrating the deviation signal. This is because the integration itself is a kind of high-frequency cutoff filter. Therefore, a signal with less noise from which a high frequency component obtained by synthesizing the integration signal and the filter output signal is removed is obtained. Further, the stability of the entire control system can be improved when the disturbance estimation means is applied to the positioning control system.

The fourth solution can be described as a disk device control method as follows. That is,
A position error signal corresponding to the current position of the head is generated from servo information recorded in advance on the disk and detected by the head,
Generating a position control signal corresponding to the position error signal;
Generating a voltage estimation signal that is an estimate of the voltage signal from the position control signal and a voltage signal generated in driving the actuator means;
Comparing the voltage estimation signal and the voltage signal to generate a deviation signal of the difference,
A signal obtained by multiplying the integral signal obtained by integrating the deviation signal by the first coefficient and a filter output signal obtained by blocking the high frequency component of the proportional signal proportional to the deviation signal are added to the signal multiplied by the second coefficient. To generate a disturbance estimation signal,
The position control signal and the disturbance estimation signal are combined to generate the drive signal,
The actuator means is driven by the drive signal to position the head with respect to the disk.

  According to this disk device control method, the same effect as described above is exhibited.

In the third or fourth solving means described above, it is preferable to configure as follows. That is,
The disturbance estimation means includes:
A comparison means for inputting a voltage signal detected by the voltage detection means;
First multiplying means for multiplying the position control signal by a coefficient comprising a first transfer function;
Second multiplication means for multiplying the output of the comparison means by a coefficient comprising a second transfer function;
First integrating means for integrating the output of the comparing means;
A second integration unit that integrates a value obtained by subtracting an addition value of the output of the second multiplication unit and the output of the first integration unit from the output of the first multiplication unit; Compares the output of the second integration means and the voltage signal, and outputs the difference to the second multiplication means and the first integration means. The feature here is that the position control signal is input to the first multiplication means.

  The effect | action by this structure is as follows. The output of the first multiplication means that inputs the position control signal is a drive torque estimation signal corresponding to the drive torque that acts on the actuator means. The output of the second integration means is a voltage estimation signal for the voltage signal detected by the voltage detection means. The deviation signal output from the comparison means that takes the difference from the voltage estimation signal from the second integration means is provided to the first integration means and the second multiplication means. The addition value of the output of the second multiplication means and the output of the first integration means is subtracted from the output of the first multiplication means and provided to the second integration means. A signal obtained by adding an integral signal obtained by integrating the deviation signal and a proportional signal proportional to the deviation signal at a constant ratio is a disturbance estimation signal.

  As a result of the above, the generated disturbance estimation signal corresponds to an accurate estimation of the disturbance received by the actuator means. Since feedforward control is performed to cancel the disturbance with the disturbance estimation signal accurately determined in this way, it is possible to satisfactorily compensate for the disturbance in the following operation, even if the fluctuation of the disturbance is large during the following operation. Therefore, the head positioning control with respect to the target track can be stably performed, and the positioning accuracy can be improved.

  Further, there is no need to add the first integration means and the second multiplication means required in the above solution means, and the means for the addition can be omitted, resulting in a simplified configuration. be able to.

In each of the above solutions, it is preferable to set the first coefficient (k ₁ ) and the second coefficient (k ₂ ) of the arithmetic expression for generating the disturbance estimation signal as follows.

That is, the first coefficient (k ₁₎ the ratio between said second coefficient _{(k 2) (= k 2} / k 1) is substantially ^{ωo 2 / (ωo 2 -ωd 2} ) ( however, .omega.o is the The estimated frequency of the disturbance estimation means, ωd, is set to be the disturbance frequency).

  According to this, the phase lag of the disturbance estimation signal with respect to the disturbance can be made substantially zero, and the disturbance estimation signal is an estimate of the disturbance very accurately.

  Further, when the first coefficient is set to 1, the number of multipliers and adders can be reduced, and the configuration can be simplified.

  A preferable aspect in the above is that the control band of the disturbance estimation unit is set larger than the control band of the position control unit.

  The effect | action by this is as follows. To widen the control band of the positioning control system is to increase the proportional gain, but there is an upper limit depending on the sampling frequency of the sector servo of the disk device and the inherent mechanical resonance frequency. On the other hand, the disturbance estimation means is not affected by the sampling frequency of the sector servo of the disk device. Therefore, in the disturbance estimation means, the control band (estimated frequency) can be set higher than the control band of the positioning control system. As a result, the head can accurately follow the target track over a higher control band.

  The technology described so far can be advantageously applied to control of loading / unloading of the head with respect to the disk. Hereinafter, the case of load / unload control will be described.

The disk device of the present invention comprises:
Actuator means for loading / unloading the head with respect to the disk;
Driving means for the actuator means;
Voltage detection means for detecting a voltage generated in driving the actuator means and outputting a voltage signal;
Disturbance estimation means for estimating the magnitude of disturbance applied to the head from the drive signal and the voltage signal in the drive means, and generating a disturbance estimation signal;
Speed control means for generating a speed control signal from the speed command signal and the voltage signal;
And correction means for synthesizing the drive signal from the speed control signal and the disturbance estimation signal.

Further, the disturbance estimation means includes:
A comparison means for comparing the voltage estimation signal generated by the disturbance estimation means with the voltage signal and outputting a deviation signal;
Adding means for adding the signal obtained by multiplying the integral signal obtained by integrating the deviation signal by the first coefficient and the signal obtained by multiplying the proportional signal proportional to the deviation signal by the second coefficient to generate the disturbance estimation signal; I have.

  The voltage signal is a derivative of the position and contains velocity information. A speed control signal is generated by the difference between the speed command signal and the voltage signal. Further, in order to cancel the disturbance received from the head retracting member such as the lamp block, the magnitude of the disturbance is estimated. Two elements are used in estimating the magnitude of the disturbance. One is a voltage signal obtained by detecting a voltage generated in driving the actuator means. The other is a drive signal in the drive means of the actuator means. Here, the drive signal in the drive unit may be input to the drive unit or may be output from the drive unit. Further, instead of the drive signal in the drive means, a speed control signal that is a basis for generating the drive signal may be used.

  Disturbance estimation means for estimating the magnitude of the disturbance is provided. With this disturbance estimation means, a disturbance estimation signal is generated with the voltage signal detected by the voltage detection means and the drive signal (including the case of the speed control signal) in the drive means as inputs. The disturbance estimation signal generated based on the two factors is an accurate estimate of the magnitude of the disturbance actually applied to the head.

  The disturbance estimation signal determined as described above is combined with the speed control signal to generate a drive signal, and the actuator signal of the head is driven using the drive signal. Thereby, the disturbance applied to the head is satisfactorily canceled, so that the speed control can be stably performed even when the fluctuation of the disturbance on the head retracting member is large during loading / unloading.

  The present invention is not limited to the above, but goes further and considers the following points.

  The disturbance estimation unit generates a voltage estimation signal corresponding to the input voltage signal, compares the voltage estimation signal with the input voltage signal, and generates a difference deviation signal. Further, an integral signal obtained by integrating the deviation signal and a proportional signal proportional to the deviation signal are generated, and an addition signal of the integral signal and the proportional signal is fed back to generate the voltage estimation signal, so that the deviation signal approaches zero. .

  Here, as a basic idea, there is an idea that a disturbance estimation signal is generated based only on the integrated signal with respect to generation of the disturbance estimation signal to be returned to the correcting means. Even when the disturbance estimation signal is generated based only on the integral signal, if the actuator means is driven by a drive signal obtained by synthesizing the disturbance estimation signal and the position control signal, the above-described effect is exhibited and compensation for the disturbance is performed. I can.

  However, when the disturbance estimation signal is generated based only on the integral signal, a phase difference occurs between the disturbance estimation signal and the actual disturbance, and the disturbance estimation signal causes a phase lag with respect to the actual disturbance. If the actuator means is driven by a drive signal based on a disturbance estimation signal including a phase delay, the effect of compensation for the disturbance is exhibited, but there is still an influence of the phase delay. There is room for improvement here, and the present invention is further advanced to add the following means in order to perform sufficient compensation.

That is, the disturbance estimation means adds the integral signal of the deviation signal and the proportional signal of the deviation signal at a constant ratio to generate a disturbance estimation signal. The disturbance estimation signal τdest can be expressed as [τdest = k ₁ · a + k ₂ · b], where a is the integral signal, b is the proportional signal, and k ₁ and k ₂ are both non-zero coefficients. The proportional signal has a phase advanced by 90 degrees with respect to the integral signal. Therefore, the phase delay can be reduced by appropriately combining the integral signal and the proportional signal. That is, it is possible to generate a disturbance estimation signal that is closer to the actual disturbance. The disturbance estimation signal in which the phase lag is suppressed is combined with the position control signal in the correction means, and the actuator means is driven by the obtained drive signal, so that the bearing friction, the elastic force, the inertial force, etc. acting on the actuator means are reduced. Compensation for disturbance can be sufficiently satisfactorily performed. As a result, speed control can be stably performed even when the fluctuation of the disturbance on the head retracting member is large during loading / unloading. That is, the reliability of the head load / unload operation can be improved. As a secondary effect, the track density can be substantially improved and the realization of a large capacity disk device is promoted.

  Hereinafter, the present invention described above will be described at a more specific level.

As a fifth solution, the disk device according to the present invention includes the following plural components. That is,
Actuator means for loading / unloading the head with respect to the disk;
Driving means for the actuator means;
Voltage detection means for detecting a voltage generated in driving the actuator means and outputting a voltage signal;
Disturbance estimation means for estimating the magnitude of disturbance applied to the head from the drive signal and the voltage signal in the drive means, and generating a disturbance estimation signal;
Speed control means for generating a speed control signal from the speed command signal and the voltage signal;
And correction means for synthesizing the drive signal from the speed control signal and the disturbance estimation signal.

Further, the disturbance estimation means includes:
A comparison means for comparing the voltage estimation signal generated by the disturbance estimation means with the voltage signal and outputting a deviation signal;
Adding means for adding the signal obtained by multiplying the integral signal obtained by integrating the deviation signal by the first coefficient and the signal obtained by multiplying the proportional signal proportional to the deviation signal by the second coefficient to generate the disturbance estimation signal; I have.

  In this configuration, the drive signal in the drive means may be input to the drive means or may be output from the drive means, and this is the same in the following.

The operation of the fifth solving means is as follows. The disturbance estimation means applies a disturbance applied to the actuator means (bearing friction, elastic force of the FPC connected to the electronic circuit board, externally applied) based on the drive signal applied to the drive means of the actuator means and the voltage signal detected from the actuator means. Estimate the magnitude of the inertia force caused by shock or vibration). Here, the disturbance estimation signal is not generated based only on the integration signal of the deviation signal, which is the difference between the voltage estimation signal and the voltage signal, but the integration signal and the proportional signal are kept constant by using the proportional signal of the deviation signal. To generate a disturbance estimation signal [τdest = k ₁ · a + k ₂ · b]. Thereby, the disturbance estimation signal in a state closer to the actual disturbance can be generated. The disturbance estimation signal in which the phase delay is suppressed is combined with the speed control signal in the correction means, and the actuator means is driven with the obtained drive signal, so that the bearing friction, the elastic force, the inertial force, etc. acting on the actuator means are reduced. Compensation for disturbance can be sufficiently satisfactorily performed. As a result, speed control can be stably performed even when the fluctuation of the disturbance on the head retracting member is large during loading / unloading. That is, the reliability of the head load / unload operation can be improved. As a secondary effect, the track density can be substantially improved and the realization of a large capacity disk device is promoted.

The fifth solution can be described as a disk device control method as follows. That is,
Generate a speed control signal corresponding to the speed command,
A voltage estimation signal that is an estimation of the voltage signal is generated based on a drive signal of the actuator means for loading / unloading the head and a voltage signal generated in driving the actuator means,
Comparing the voltage estimation signal and the voltage signal to generate a deviation signal of the difference,
A disturbance estimation signal is generated by adding a signal obtained by multiplying the integral signal obtained by integrating the deviation signal by a first coefficient and a signal obtained by multiplying a proportional signal proportional to the deviation signal by a second coefficient;
Combining the speed control signal and the disturbance estimation signal to generate the drive signal;
The actuator means is driven by the drive signal to load / unload the head with respect to the disk.

  According to this disk device control method, the same effect as described above is exhibited.

As a sixth solution, the disk device according to the present invention includes the following plurality of components. That is,
Actuator means for loading / unloading the head with respect to the disk;
Driving means for the actuator means;
Voltage detection means for detecting a voltage generated in driving the actuator means and outputting a voltage signal;
Disturbance estimation means for estimating the magnitude of disturbance applied to the head from the drive signal and the voltage signal in the drive means, and generating a disturbance estimation signal;
Speed control means for generating a speed control signal from the speed command signal and the voltage signal;
And correction means for synthesizing the drive signal from the speed control signal and the disturbance estimation signal.

Further, the disturbance estimation means includes:
A comparison means for comparing the voltage estimation signal generated by the disturbance estimation means with the voltage signal and outputting a deviation signal;
Filter means for cutting off a high frequency component of a proportional signal proportional to the deviation signal and generating a filter output signal;
And adding means for adding the signal obtained by multiplying the integral signal obtained by integrating the deviation signal by the first coefficient and the signal obtained by multiplying the filter output signal by the second coefficient to generate the disturbance estimation signal.

  The operation of the sixth solving means is basically the same as that of the fifth solving means. And noise can be reduced by adding the filter means to the disturbance estimating means. The filter means generates a filter output signal by cutting off a high frequency component of the proportional signal. On the other hand, the high frequency component of the integrated signal is cut off in the process of integrating the deviation signal. This is because the integration itself is a kind of high-frequency cutoff filter. Therefore, the disturbance estimation signal obtained by synthesizing the integration signal and the filter output signal is a signal with less noise from which high-frequency components are removed. In addition, the stability of the entire control system can be improved when the disturbance estimation means is applied to the speed control system.

The sixth solving means is described as a disk device control method as follows. That is,
Generate a speed control signal corresponding to the speed command,
A voltage estimation signal that is an estimation of the voltage signal is generated based on a drive signal of the actuator means for loading / unloading the head and a voltage signal generated in driving the actuator means,
Comparing the voltage estimation signal and the voltage signal to generate a deviation signal of the difference,
A signal obtained by multiplying the integral signal obtained by integrating the deviation signal by the first coefficient and a filter output signal obtained by blocking the high frequency component of the proportional signal proportional to the deviation signal are added to the signal multiplied by the second coefficient. To generate a disturbance estimation signal,
Combining the speed control signal and the disturbance estimation signal to generate the drive signal;
The actuator means is driven by the drive signal to load / unload the head with respect to the disk.

  According to this disk device control method, the same effect as described above is exhibited.

In the fifth or sixth solving means described above, the following configuration is preferable. That is,
Comparing means for inputting the voltage signal detected by the voltage detecting means for the configuration of the disturbance estimating means,
First multiplication means for multiplying the drive signal by a coefficient comprising a first transfer function;
Second multiplication means for multiplying the output of the comparison means by a coefficient comprising a second transfer function;
First integrating means for integrating the output of the comparing means;
And a second integration unit that integrates a value obtained by subtracting an addition value of the output of the second multiplication unit and the output of the first integration unit from the output of the first multiplication unit.

  Further, the comparison means compares the output of the second integration means with the voltage signal and outputs the difference to the second multiplication means and the first integration means.

  The effect | action by this structure is as follows. The output of the first multiplication means for inputting the drive signal is a drive torque estimation signal corresponding to the drive torque acting on the actuator means. The output of the second integration means is a voltage estimation signal for the voltage signal detected by the voltage detection means. The deviation signal output from the comparison means that takes the difference between the voltage estimation signal from the second integration means and the voltage signal is provided to the first integration means and the second multiplication means. The addition value of the output of the second multiplication means and the output of the first integration means is subtracted from the output of the first multiplication means and provided to the second integration means. A signal obtained by adding an integral signal obtained by integrating the deviation signal and a proportional signal proportional to the deviation signal at a constant ratio is a disturbance estimation signal.

  As a result of the above, the generated disturbance estimation signal corresponds to an accurate estimation of the disturbance received by the actuator means. And since feedforward control is performed so as to cancel the disturbance with the disturbance estimation signal accurately determined in this way, it is possible to satisfactorily compensate for disturbances such as friction on the head retracting member in the load / unload operation, Even if the fluctuation of disturbance is large during the load / unload operation, the speed control can be performed sufficiently stably. That is, the reliability of the head load / unload operation can be improved.

As a seventh solution, the disk device according to the present invention includes the following plural components. That is,
Actuator means for loading / unloading the head with respect to the disk;
Driving means for the actuator means;
Voltage detection means for detecting a voltage generated in driving the actuator means and outputting a voltage signal;
Disturbance estimation means for estimating the magnitude of disturbance applied to the head from the speed control signal and the voltage signal and generating a disturbance estimation signal;
Speed control means for generating the speed control signal from a speed command signal and the voltage signal;
And correction means for synthesizing the drive signal from the speed control signal and the disturbance estimation signal.

Further, the disturbance estimation means includes:
A comparison means for comparing the voltage estimation signal generated by the disturbance estimation means with the voltage signal and outputting a deviation signal;
Adding means for adding the signal obtained by multiplying the integral signal obtained by integrating the deviation signal by the first coefficient and the signal obtained by multiplying the proportional signal proportional to the deviation signal by the second coefficient to generate the disturbance estimation signal; I have.

  In the seventh solution means, the disturbance estimation means uses a speed control signal from the speed control means in place of the drive signal in the drive means referred to in the sixth solution means. The operation is as follows. The disturbance estimating means can accurately estimate the magnitude of the disturbance applied to the head based on the speed control signal given from the speed control means to the driving means to drive the actuator means and the voltage signal detected from the actuator means. . A disturbance related to the estimation is a disturbance estimation signal. Here, in particular, it is important to be able to accurately estimate the magnitude of the disturbance applied to the head from the speed control signal and the voltage signal.

  In order to cancel the disturbance applied to the head with the disturbance estimation signal accurately determined as described above, the disturbance estimation signal is combined with the speed control signal to generate a drive signal, and the head actuator means using the drive signal If the is driven, the disturbance applied to the head can be canceled satisfactorily. That is, it is possible to compensate for external force such as friction acting on the actuator means, and furthermore, since speed control is directly related to it, the load on the head retracting member such as a ramp block is loaded or unloaded. Even if the fluctuation of the disturbance is large, the speed control can be performed sufficiently stably. That is, the reliability of the head load / unload operation can be improved.

The seventh solving means is described as a disk device control method as follows. That is,
Generate a speed control signal corresponding to the speed command,
Generating a voltage estimation signal that is an estimate of the voltage signal based on the speed control signal and a voltage signal generated in driving the actuator means;
Comparing the voltage estimation signal and the voltage signal to generate a deviation signal of the difference,
A disturbance estimation signal is generated by adding a signal obtained by multiplying the integral signal obtained by integrating the deviation signal by a first coefficient and a signal obtained by multiplying a proportional signal proportional to the deviation signal by a second coefficient;
Combining the speed control signal and the disturbance estimation signal to generate the drive signal;
The actuator means is driven by the drive signal to load / unload the head with respect to the disk.

  According to this disk device control method, the same effect as described above is exhibited.

As an eighth solving means, the disk device according to the present invention comprises the following plural components. That is,
Actuator means for loading / unloading the head with respect to the disk;
Driving means for the actuator means;
Voltage detection means for detecting a voltage generated in driving the actuator means and outputting a voltage signal;
Disturbance estimation means for estimating the magnitude of disturbance applied to the head from the speed control signal and the voltage signal and generating a disturbance estimation signal;
Speed control means for generating the speed control signal from a speed command signal and the voltage signal;
And correction means for synthesizing the drive signal from the speed control signal and the disturbance estimation signal.

Further, the disturbance estimation means includes:
A comparison means for comparing the voltage estimation signal generated by the disturbance estimation means with the voltage signal and outputting a deviation signal;
Filter means for cutting off a high frequency component of a proportional signal proportional to the deviation signal and generating a filter output signal;
And adding means for adding the signal obtained by multiplying the integral signal obtained by integrating the deviation signal by the first coefficient and the signal obtained by multiplying the filter output signal by the second coefficient to generate the disturbance estimation signal.

  The operation of the eighth solving means is basically the same as that of the seventh solving means. And noise can be reduced by adding the filter means to the disturbance estimating means. The filter means generates a filter output signal by cutting off a high frequency component of the proportional signal. On the other hand, the high frequency component of the integrated signal is cut off in the process of integrating the deviation signal. This is because the integration itself is a kind of high-frequency cutoff filter. Therefore, the disturbance estimation signal obtained by synthesizing the integration signal and the filter output signal is a signal with less noise from which high-frequency components are removed. In addition, the stability of the entire control system can be improved when the disturbance estimation means is applied to the speed control system.

The eighth solving means is described as a disk device control method as follows. That is,
Generate a speed control signal corresponding to the speed command,
Generating a voltage estimation signal that is an estimate of the voltage signal based on the speed control signal and a voltage signal generated in driving the actuator means;
Comparing the voltage estimation signal and the voltage signal to generate a deviation signal of the difference,
A signal obtained by multiplying the integral signal obtained by integrating the deviation signal by the first coefficient and a filter output signal obtained by blocking the high frequency component of the proportional signal proportional to the deviation signal are added to the signal multiplied by the second coefficient. To generate a disturbance estimation signal,
Combining the speed control signal and the disturbance estimation signal to generate the drive signal;
The actuator means is driven by the drive signal to load / unload the head with respect to the disk.

  According to this disk device control method, the same effect as described above is exhibited.

In the seventh or eighth solving means described above, the following configuration is preferable. That is,
The disturbance estimation unit includes a comparison unit to which the voltage signal detected by the voltage detection unit is input;
First multiplying means for multiplying the position control signal by a coefficient comprising a first transfer function;
Second multiplication means for multiplying the output of the comparison means by a coefficient comprising a second transfer function;
First integrating means for integrating the output of the comparing means;
And a second integration unit that integrates a value obtained by subtracting an addition value of the output of the second multiplication unit and the output of the first integration unit from the output of the first multiplication unit.

  Further, the comparison means compares the output of the second integration means with the voltage signal and outputs the difference to the second multiplication means and the first integration means.

  The effect | action by this structure is as follows. The output of the first multiplication means for inputting the drive signal is a drive torque estimation signal corresponding to the drive torque acting on the actuator means. The output of the second integration means is a voltage estimation signal for the voltage signal detected by the voltage detection means. The deviation signal output from the comparison means that takes the difference between the voltage estimation signal from the second integration means and the voltage signal is provided to the first integration means and the second multiplication means. The addition value of the output of the second multiplication means and the output of the first integration means is subtracted from the output of the first multiplication means and provided to the second integration means. A signal obtained by adding an integral signal obtained by integrating the deviation signal and a proportional signal proportional to the deviation signal at a constant ratio is a disturbance estimation signal.

  As a result of the above, the generated disturbance estimation signal corresponds to an accurate estimation of the disturbance received by the actuator means. And since feedforward control is performed so as to cancel the disturbance with the disturbance estimation signal accurately determined in this way, it is possible to satisfactorily compensate for disturbances such as friction on the head retracting member in the load / unload operation, Even if the fluctuation of disturbance is large during the load / unload operation, the speed control can be performed sufficiently stably. That is, the reliability of the head load / unload operation can be improved.

  Further, there is no need to add the first integration means and the second multiplication means required in the above solution means, and the means for the addition can be omitted, resulting in a simplified configuration. be able to.

In each of the above solutions, it is preferable to set the first coefficient (k ₁ ) and the second coefficient (k ₂ ) of the arithmetic expression for generating the disturbance estimation signal as follows.

That is, the first coefficient (k ₁₎ the ratio between said second coefficient _{(k 2) (= k 2} / k 1) is substantially ^{ωo 2 / (ωo 2 -ωd 2} ) ( however, .omega.o is the The estimated frequency of the disturbance estimation means, ωd, is set to be the disturbance frequency).

  According to this, the phase lag of the disturbance estimation signal with respect to the disturbance can be made substantially zero, and the disturbance estimation signal is an estimate of the disturbance very accurately.

  Further, when the first coefficient is set to 1, the number of multipliers and adders can be reduced, and the configuration can be simplified.

  A preferable aspect in the above is that the control band of the disturbance estimation unit is set larger than the control band of the speed control unit.

  The effect | action by this is as follows. To increase the control band of the speed control system is to increase the proportional gain, but there is an upper limit depending on the sampling frequency of the sector servo of the disk device and the inherent mechanical resonance frequency. On the other hand, the disturbance estimation means is not affected by the sampling frequency of the sector servo of the disk device. Therefore, in the disturbance estimation means, the control band (estimated frequency) can be set higher than the control band of the speed control system. As a result, the head can accurately follow the target track over a higher control band.

  As described above, according to the disk device of the present invention, the disturbance estimating means can accurately detect the disturbance due to the friction received by the head from the head retracting member such as the ramp block during the load / unload operation. Even if the fluctuation of the disturbance is large, the speed control can be stably performed. That is, the reliability of the head load / unload operation can be improved.

  Further, according to the disk device of the present invention, not only the speed control in the head loading / unloading but also the speed control at the time of seek operation for moving the head at a high speed with respect to the target track, the servo signal recorded on the disk Can be realized without reproducing with the head, and the seek speed of the disk device can be increased.

In particular, the disturbance estimation signal generated by the disturbance estimation means is obtained by adding the integral signal of the deviation signal between the voltage estimation signal and the voltage signal and the proportional signal of the deviation signal at a constant ratio (τdest = k ₁ · g 2 Α / s + k ₂ · g 1 · α), which can be closer to the actual disturbance. As a result, it is possible to sufficiently compensate for disturbances such as bearing friction, elastic force and inertial force acting on the actuator means, and not only during loading / unloading but also in the following operation toward the target track Even if the fluctuation of the disturbance acting on the means is large, the load / unload operation and the head positioning control to the target track can be stably performed. Therefore, even if the influence of the disturbance acting on the actuator means on the positioning control system increases due to the reduction in size and weight of the actuator means, it is possible to cope with sufficiently high head positioning accuracy, increasing the track density and increasing the capacity. The disk device can be realized.

  The present invention functions most advantageously when applied to a magnetic disk device. However, the present invention is not necessarily limited to only a magnetic disk device, and may be applied to other forms of information recording devices such as an optical disk device and a magneto-optical disk device. It does not matter if it is applied.

  Hereinafter, specific embodiments of a disk apparatus according to the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected and demonstrated to what has the same function.

(Embodiment 1)
FIG. 1 is a block diagram showing the configuration of a disk device according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 1 denotes a magnetic disk (hereinafter abbreviated as a disk), which is rotated by a spindle motor (not shown). 2 is a magnetic head (hereinafter abbreviated as a head) for recording / reproducing data on / from the disk 1, and 3 is an arm. The head 2 mounted on one end is rotated around a bearing 4, thereby rotating the head 2. Move to the target track on the disc 1. Reference numeral 5 denotes a drive coil provided at the rear end of the arm 3, and reference numeral 6 denotes a stator (yoke). A magnet (permanent magnet; not shown) is disposed on a surface facing the drive coil 5. The stator 6 is composed of a pair of yokes facing each other through a gap, and the magnet is fixed to at least one of the yokes in the gap. The arm 3 receives a rotational force due to the interaction between the magnetic flux generated by the magnet disposed in the stator 6 and the magnetic field generated by the current supplied to the drive coil 5. An arm 7, a bearing 4, a drive coil 5, and a stator 6 constitute an actuator 7.

  Reference numeral 10 denotes a driver, and 11 denotes a voltage detector included in the driver 10, which detects a voltage generated at both ends of the drive coil 5 and outputs a voltage signal Ed. A disturbance estimator 12 estimates a disturbance (torque) τd acting on the arm 3 from a voltage signal Ed output from the voltage detector 11 and a drive signal u which is an input of the driver 10, and outputs a disturbance estimation signal τdest. To do.

  A track position signal is recorded in advance as servo information in each sector of the disk 1, and this position signal is read by the head 2. The position detector 13 detects the current position of the head 2 based on the position signal read by the head 2 and generates a position error signal e indicating a difference from the target track position r. The position controller 14 receives the position error signal e generated by the position detector 13, performs amplification and phase compensation, and generates a position control signal c. A corrector 15 receives a position control signal c from the position controller 14 and a disturbance estimation signal τdest from the disturbance estimator 12, performs a correction operation by the corrector 15, generates a drive signal u, and generates the drive signal u. Is output to the driver 10.

  The driver 10 supplies a drive current Ia to the drive coil 5 in accordance with the input drive signal u, and rotates the arm 3 around the bearing 4. As a result, the head 2 attached to the tip of the arm 3 is rotationally moved, and the head 2 is positioned with high accuracy with respect to a target track formed with a narrow track pitch.

  Next, the operation of the positioning control system of the disk device according to the present embodiment will be described with reference to FIG. FIG. 2 is a block diagram showing the overall configuration of the position control system in the disk device of the present embodiment.

  A portion 30 surrounded by a one-dot chain line in the figure is a block of the disturbance estimator 12. Similarly, a portion 47 surrounded by a one-dot chain line is a block of the corrector 15, and a portion 55 surrounded by a one-dot chain line is a block of the voltage detector 11. In FIG. 2, s represents a Laplace operator. Further, in FIG. 2, the hold element by sector servo sampling is omitted for the sake of simplicity.

  In FIG. 2, if the current track position detected by the head 2 is x, the position error signal e for the target track position r is expressed by (Equation 1), and this position error signal e is obtained by the comparator 20.

図２のブロック２１で表される位置制御器１４は、比較器２０から出力される位置誤差信号ｅに伝達関数Ｇx（ｚ）のディジタルフィルタ処理を施し、位置制御信号ｃを生成して、ブロック４７で表される補正器１５へ出力する。位置決め制御系は、通常のＰＩＤ制御が施され、位置制御器１４の伝達関数は、（数２）で表現できる。

The position controller 14 represented by the block 21 in FIG. 2 performs a digital filter process of the transfer function Gx (z) on the position error signal e output from the comparator 20 to generate a position control signal c. It outputs to the corrector 15 represented by 47. The positioning control system is subjected to normal PID control, and the transfer function of the position controller 14 can be expressed by (Equation 2).

ここで、ｚ^-1は１サンプル遅延を示し、Ｋxは位置決め制御系の比例ゲインを示す。係数ａd、ａiは周波数特性を表す定数を示し、係数ａ_dは微分係数、係数ａ_iは積分係数である。位置制御信号ｃは加算器４６を経由して駆動信号ｕとなる。駆動信号ｕは、ブロック２２（伝達関数はｇm）の駆動器１０において、電圧信号からｇm倍の電流信号に変換され、駆動電流Ｉaを出力する。ブロック２３で表されるアクチュエータ７において、駆動コイル５に通電される駆動電流Ｉaは、それが作る磁界と前述した固定子６のマグネットの磁束との相互作用により伝達関数Ｋtで駆動トルクτに変換される。ここで、伝達関数Ｋtはアクチュエータ７のトルク定数である。ブロック２４の伝達関数（Ｌb／Ｊ・ｓ）は、アーム３に作用する駆動トルクτからヘッド２の移動速度ｖへの伝達特性を表わす。ここで、Ｊはアーム３の慣性モーメントを示し、Ｌbはアーム３の軸受４からヘッド２までの距離を示している。ブロック２５は積分器で、伝達関数は１／ｓで表され、ヘッド２の移動速度ｖが現在トラック位置ｘに変換される。

Here, z ⁻¹ represents one sample delay, and Kx represents a proportional gain of the positioning control system. Coefficient ad, ai represents a constant representing a frequency characteristic, the coefficient a _d is the derivative, the coefficient a _i is an integration coefficient. The position control signal c becomes the drive signal u via the adder 46. The drive signal u is converted from a voltage signal to a current signal multiplied by gm in the driver 10 of the block 22 (transfer function is gm), and a drive current Ia is output. In the actuator 7 represented by the block 23, the drive current Ia energized to the drive coil 5 is converted into the drive torque τ by the transfer function Kt due to the interaction between the magnetic field generated by the magnet and the magnetic flux of the stator 6 described above. Is done. Here, the transfer function Kt is a torque constant of the actuator 7. The transfer function (Lb / J · s) of the block 24 represents a transfer characteristic from the driving torque τ acting on the arm 3 to the moving speed v of the head 2. Here, J represents the moment of inertia of the arm 3, and Lb represents the distance from the bearing 4 of the arm 3 to the head 2. Block 25 is an integrator, the transfer function is expressed by 1 / s, and the moving speed v of the head 2 is converted into the current track position x.

  In the actuator 7, the block 26 outputs an induced voltage Ea generated at both ends of the drive coil 5 as the actuator 7 rotates, and the block 27 generates a voltage drop generated when the drive current Ia is supplied to the drive coil 5. Minute (Ra + La · s) · Ia is output and added by the adder 28 to be output as the terminal voltage Va of the actuator 7. That is,

の関係がある。ここで、Ｒaは、駆動コイル５のコイル抵抗、Ｌaは駆動コイル５のインダクタンスを示す。

There is a relationship. Here, Ra represents the coil resistance of the drive coil 5, and La represents the inductance of the drive coil 5.

  The disturbance τd acting on the arm 3 such as the bearing friction of the actuator 7, the elastic force of the FPC connecting the actuator 7 and the electronic circuit board, and the inertial force received by the actuator 7 due to external shock and vibration applied to the disk device 29 can be expressed in the form input to the previous stage of the block 24.

  A portion 55 surrounded by an alternate long and short dash line in FIG. 2 indicates a block of the voltage detector 11, and this block 55 is subtracted from the block 39 having the same transfer function as the transfer function of the block 27 included in the actuator 7. A container 36 is included. The block 39 outputs a voltage drop (Ran + Lan · s) · Ia generated when the drive current Ia is supplied to the drive coil 5 and subtracts it from the terminal voltage Va of the actuator 7 by the subtractor 36 to generate a voltage signal. Ed is output.

  2 indicates a block of the disturbance estimator 12. The block 30 includes a block 32 having the same transfer function as that of the block 22 as the driver 10, and an actuator. 7 includes a block 33 having the same transfer function as that of the block 23, a block 34 having the same transfer function as that of the block 24, and a block 35 having the same transfer function as that of the block 26. . The block 32 and the block 33 together constitute a first multiplier 41. 43 is a first integrator, and 44 is a second multiplier. The block 34 and the block 35 are combined to constitute a second integrator 42. Here, the suffix “n” of each constant of the block 30 indicates a nominal value, and the variable with “est” indicates an estimated value.

  The drive signal u input to the block 22 is also input to the block 32 constituting the first multiplier 41 in the disturbance estimator 12 and is multiplied by (gmn · Ktn) between the block 32 and the block 33, so that the arm 3 The same drive torque estimation signal τest as the drive torque τ acting on the motor is obtained.

In FIG. 2, the speed estimation signal vest is output from the block 34. In block 35, the induced voltage estimation signal Eaest obtained by multiplying the speed estimation signal vest by Kvn is input to the comparator 37, compared with the actually detected voltage signal Ed, and the resulting deviation signal α ( = Eaest−Ed) is input to the first integrator 43 and the second multiplier 44. The first integrator 43 integrates the deviation signal α and multiplies it by g 2 to output an integrated signal a. The second multiplier 44 outputs a proportional signal b obtained by multiplying the deviation signal α by g1. Integration signal a is input to a multiplier 61, is ₁ times k is input to the adder 63. Similarly, the proportional signal b is input to the multiplier 62, multiplied by k ₂ , and input to the adder 63. The adder 63 outputs a disturbance estimation signal τdest for the disturbance. That is,

の関係がある。積分信号ａが偏差信号αを積分（１／ｓ倍）したものであるのに対して、比例信号ｂは偏差信号αを実数倍したものであるので、積分信号ａは比例信号ｂに対して９０°の位相遅れをもっている。

There is a relationship. The integral signal a is obtained by integrating the deviation signal α (1 / s times), whereas the proportional signal b is obtained by multiplying the deviation signal α by a real number. It has a 90 ° phase lag.

  The integration signal a and the proportional signal b are input to the adder 38. The output of the adder 38 is input to the subtractor 31, and the result γ obtained by subtracting the output (a + b) of the adder 38 from the drive torque estimation signal τest output from the block 33 is output to the block 34.

  The coefficient g1 of the second multiplier 44 and the coefficient g2 of the first integrator 43 are constants for stabilizing the operation of the disturbance estimator 12, and details thereof will be described later.

  In FIG. 2, reference numeral 60 denotes a high-frequency cutoff filter, which performs a filtering process of the transfer function F (s) on the disturbance estimation signal τdest output from the disturbance estimator 12 of the block 30, and includes a high-frequency band included in the disturbance estimation signal τdest Remove ingredients. The signal that has passed through the high-frequency cutoff filter 60 is output to the block 47. The high-frequency cutoff filter 60 can not only obtain a signal with less noise by removing a high-frequency component included in the disturbance estimation signal τdest, but also can improve the overall control system when the disturbance estimator is applied to the positioning control system. There is also an effect of improving stability.

  In FIG. 2, reference numeral 47 surrounded by a one-dot chain line is a block of the corrector 15. The block 45 included in the corrector 15 is required to generate a driving force having a magnitude corresponding to the disturbance estimation signal τdest in the arm 3 by multiplying the disturbance estimation signal τdest by 1 / (gmn · Ktn). A correction signal β to the driver 10 is generated. The correction signal β is added to the position control signal c in the adder 46.

  Next, the operation of the disturbance estimator 12 in the block 30 will be described in detail with reference to FIG. FIG. 3A is a block diagram in which the block 30 of FIG. 2 is rewritten and shows transmission from the input of the drive signal u to the output of the disturbance estimation signal τdest.

Here, the coefficients k ₁ and k ₂ of the multiplier 61 and the multiplier 62 in FIG.

に設定したときについて説明する。

The case when set to.

  FIG. 3B is a modification of the block diagram of FIG. 3A by equivalently converting and moving the input position (comparator 37) of the voltage signal Ed in the block diagram of FIG. FIG. Here, in order to simplify the explanation, the value of gm in block 22 and the value of gmn in block 32 in FIG.

と仮定し、駆動電流Ｉa（＝ｇm・ｕ）と推定電流Ｉaest（＝ｇmn・ｕ）とが等しいものとした。

It is assumed that the drive current Ia (= gm · u) and the estimated current Iaest (= gmn · u) are equal.

  If the magnitude of the voltage signal Ed is multiplied by (Jn · s) / (Lbn · Kvn), the input position of the comparator 37 in FIG. 3 (a) becomes the input position of the subtractor 48 shown in FIG. 3 (b). It can move equivalently.

  When attention is paid to the subtractor 48 in FIG. 3B, δ which is the output of the subtractor 48 is expressed as (Equation 7).

ここで、理想的な条件として、

Here, as an ideal condition,

が成立するものとし、また、駆動コイル５のインダクタンスＬanは、抵抗Ｒanに比べて小さいため、図２の位置決め制御系のブロック線図において、電圧検出器１１に含まれるブロック３９で、駆動電流Ｉaが駆動コイル５に流れることにより発生する電圧降下分のうち、コイル抵抗Ｒanの電圧降下分だけを考慮し、インダクタンスＬanの電圧降下分を無視することにする。すなわち、

In addition, since the inductance Lan of the drive coil 5 is smaller than the resistance Ran, in the block diagram of the positioning control system of FIG. Of the voltage drop generated by flowing through the drive coil 5, only the voltage drop of the coil resistance Ran is considered and the voltage drop of the inductance Lan is ignored. That is,

と仮定すれば、減算器３６に着目し、（数３）を代入すれば電圧信号Ｅdは、（数１０）のように表される。

Assuming that, the subtracter 36 is focused, and if (Equation 3) is substituted, the voltage signal Ed is expressed as (Equation 10).

次に、図２の減算器２９、ブロック２４，２６に着目すると、（数１１）の関係がある。

Next, paying attention to the subtractor 29 and the blocks 24 and 26 in FIG.

ここで、理想的な条件として、

Here, as an ideal condition,

と仮定し、（数１０）、（数６）を（数７）に代入すると、（数７）は、（数１４）のように変形される。

Assuming that (Equation 10) and (Equation 6) are substituted into (Equation 7), (Equation 7) is transformed into (Equation 14).

すなわち、減算器４８の出力であるδは、アーム３に加わる外乱τｄに等しい。

That is, δ which is the output of the subtractor 48 is equal to the disturbance τd applied to the arm 3.

  Therefore, when the transfer function from the disturbance τd applied to the arm 3 to the disturbance estimation signal τdest is obtained from the block diagram of FIG.

（数１５）から、外乱推定器１２は、図２の一点鎖線で囲んだブロック３０内のループによって、駆動信号ｕと電圧信号Ｅdとから実際の外乱τdを２次遅れ系で推定できることが分かる。

From (Equation 15), it can be seen that the disturbance estimator 12 can estimate the actual disturbance τd from the drive signal u and the voltage signal Ed by a second-order lag system by the loop in the block 30 surrounded by the one-dot chain line in FIG. .

  Here, if the natural angular frequency (estimated angular frequency) of the second-order lag system is ωo and the damping factor is ζo, the constants g1 and g2 for stabilizing the operation of the disturbance estimator 12 are the following (Equation 16) and (Expression 17)

ここで、推定角周波数ωoを位置制御帯域ｆcより十分高く設定し、ダンピングファクタζoを０．７〜１に選べば、外乱推定器１２により軸受摩擦や弾性力や慣性力などの外乱τdを正確に推定することができる。

Here, if the estimated angular frequency ωo is set sufficiently higher than the position control band fc and the damping factor ζo is selected to be 0.7 to 1, the disturbance estimator 12 accurately determines the disturbance τd such as bearing friction, elastic force, and inertial force. Can be estimated.

  When (Equation 15) is transformed using (Equation 16) and (Equation 17),

となる。すなわち、図３（ａ）の外乱推定器１２のブロック線図は、図３（ｃ）のブロック５２に示すように簡略化することができる。

It becomes. That is, the block diagram of the disturbance estimator 12 in FIG. 3A can be simplified as shown in the block 52 in FIG.

  Next, the operation of the corrector 15 indicated by the block 47 will be described in detail with reference to FIG.

  A portion 47 surrounded by an alternate long and short dash line in FIG. 2 indicates a block of the corrector 15. The block 45 outputs a correction signal β obtained by multiplying the disturbance estimation signal τdest by 1 / (gmn · Ktn) to the adder 46. That is, by multiplying the disturbance estimation signal τdest by 1 / (gmn · Ktn), the correction signal β necessary for causing the actuator 7 to generate a driving force having a magnitude corresponding to the disturbance estimation signal τdest is output to the adder 46. . Further, since the correction signal β is multiplied by gmn · Ktn by the block 22 and the block 23, the disturbance estimation signal τdest is multiplied by 1 / (gmn · Ktn) in advance in order to match the magnitude.

  In summary, the disturbance τd due to the bearing friction of the actuator 7, the elastic force of the FPC connecting the actuator 7 and the electronic circuit board, the inertial force received by the actuator 7 due to externally applied shocks and vibrations, etc. is canceled out. It can be said that the disturbance estimation signal τdest is applied to the actuator 7.

  4A is a block diagram in which portions from the adder 46 to the comparator 29 and the block 24 related to the operation of the corrector 15 are extracted from the block diagram of FIG. FIG. 4B is a block diagram in which the disturbance τd applied to the comparator 29 and the disturbance τd applied to the block 52 are combined into one τd. Note that components having the same functions as those in the block diagram of FIG.

  In the block diagram of FIG. 4A, the block 52 corresponds to the block 52 of FIG. 3C and has a transfer function represented by (Equation 15).

  Therefore, from FIG. 4B, it can be considered that the disturbance τd applied to the arm 3 from the outside is applied to the head position control system through the filter expressed by the transfer function of (Equation 19).

図５は、（数１９）で表される伝達関数Ｇd(s)の周波数特性を折れ線近似で示したものである。図５に示す伝達関数Ｇd(s)の周波数特性から角周波数ωoより低い角周波数では、ゲインは０ｄＢ以下であり、角周波数ωの下降に伴って、−２０ｄＢ／ｄｅｃ（ディケード）の減衰比で減衰している。ｄｅｃは１０倍を意味する。すなわち、伝達関数Ｇd(s)は、図５より、角周波数ωoより低い周波数を抑制することができる低域遮断フィルタ特性を有している。

FIG. 5 shows the frequency characteristic of the transfer function Gd (s) expressed by (Equation 19) by a polygonal line approximation. From the frequency characteristic of the transfer function Gd (s) shown in FIG. 5, at an angular frequency lower than the angular frequency ωo, the gain is 0 dB or less, and with an attenuation ratio of −20 dB / dec (decade) as the angular frequency ω decreases. It is decaying. Dec means 10 times. That is, the transfer function Gd (s) has a low-frequency cutoff filter characteristic that can suppress a frequency lower than the angular frequency ωo from FIG.

  That is, in the disk device of the present embodiment, even if a disturbance τd due to bearing friction, elastic force, inertial force, or the like acts on the arm 3, the disturbance τd is estimated by the disturbance estimator 12, and the disturbance estimation signal τdest is used. Control is performed so as to cancel disturbance τd applied from the outside. Therefore, the disturbance τd applied from the outside acts as if it was applied to the head positioning control system through the filter having the cutoff frequency characteristic of (Equation 19) and FIG.

  Therefore, in the disk device according to the present embodiment, the disturbance received by the actuator 7 can be suppressed with a first-order low-frequency cutoff characteristic at a frequency of the angular frequency ωo or lower. Here, the disturbance is the bearing friction of the actuator 7, the elastic force of the FPC that connects the actuator 7 and the electronic circuit board, the inertial force that the actuator 7 receives due to the impact and vibration applied to the disk device from the outside, and the like. .

  That is, in the disk device of the present embodiment, even if a disturbance τd acts on the actuator 7 from the outside, the disturbance τd is estimated by the disturbance estimator 12 and controlled so as to cancel the disturbance τd. It has the effect of applying a mechanical vibration isolation mechanism.

6 shows the disturbance suppression effect of the disturbance estimator 12 of the disk apparatus according to the present embodiment. The coefficients k ₁ and k ₂ of the multiplier 61 and the multiplier 62 in FIG. ₂ are respectively expressed as k ₁ = 1 and k ₂ = It is a time response waveform diagram for explaining the operation when set to 0 in more detail.

  FIG. 6A shows a waveform 71 (see the broken line) of the disturbance τd of the inertial force received by the actuator 7 when a sinusoidal rotational vibration is applied to the disk device from the outside, and the disturbance estimation output by the disturbance estimator 12. A waveform 72 (see solid line) of the signal τdest is shown.

  Here, the estimated frequency fo (ωo = 2πfo) for determining the control parameters g1 and g2 of (Equation 16) and (Equation 17) and the value of the damping factor ζo are set to 1 kHz and 1, respectively, to control the position control system. The band was set to 800 Hz, and the disturbance was simulated as a sine wave having a constant amplitude of 100 Hz.

  The disturbance estimator 12 estimates the disturbance τd acting on the actuator 7 from the drive signal u which is an input to the driver 10 and the voltage signal Ed output from the voltage detector 11, and there is a slight time delay, but there is an actual delay. A disturbance estimation signal τdest substantially similar to the disturbance τd is output.

  FIG. 6B shows a position error signal e when the disturbance estimation signal τdest output from the disturbance estimator 12 is input to the corrector 15 and the disturbance estimation signal τdest is applied to the actuator 7 so as to cancel the fluctuation of the disturbance. The simulation results of the waveform 74 (see the solid line) and the waveform 73 (see the broken line) of the position error signal e when the disturbance estimator 12 is not applied are shown. Even when sinusoidal rotational vibration is applied to the disk device from the outside, the position estimator 12 is applied, so that the position error signal e does not fluctuate significantly like the waveform 74, and the waveform when the disturbance estimator 12 is not applied. Compared to 73, the disturbance suppressing effect is improved about 1/3 times.

  As for the above basic technical contents, the present applicant has already proposed a patent application (see Japanese Patent Application Laid-Open No. 2002-42434). This completes the explanation of preparations before entering the main topic. Next, the main subject will be described.

  FIG. 7 is a vector diagram for explaining the operation of the disturbance estimator 12 of the disk apparatus of the present embodiment in more detail. Considering that the disturbance estimation signal τdest is obtained from the relational expression (Equation 4), the phase relationship between the actual disturbance τd and the integral signal a, the proportional signal b, and the disturbance estimation signal τdest is shown.

In the basic technical contents described above, the coefficients k ₁ and k ₂ of the multiplier 61 and the multiplier 62 in FIG. 2 are set to k ₁ = 1 and k ₂ = 0, respectively. In this case, the disturbance estimation signal τdest is

となり、積分信号ａが外乱推定信号τdestに等しくなる。

Thus, the integral signal a becomes equal to the disturbance estimation signal τdest.

When k ₁ = 1 and k ₂ = 0, the disturbance estimator 12 estimates the actual disturbance τd by a second-order lag system from (Equation 15), and therefore the phase of the disturbance estimation signal τdest Is delayed in phase by θ from the phase of the actual disturbance τd. The integral signal a is a signal obtained by integrating the deviation signal α, and the proportional signal b is a signal proportional to the deviation signal α. Therefore, the phase of the proportional signal b is advanced by 90 degrees compared to the integral signal a. Since the phase of the integral signal a is delayed by θ relative to the actual disturbance τd, the fact that the phase of the proportional signal b is 90 degrees ahead of the integral signal a is used, and the coefficient k ₁ , By appropriately setting k ₂ , the disturbance estimation signal τdest is brought close to the actual disturbance τd (see FIG. 7). This idea is the gist of the present invention.

FIG. 8 shows the disturbance suppression effect of the disturbance estimator 12 of the disk apparatus according to the present embodiment, with the coefficients k ₁ and k ₂ of the multiplier 61 and the multiplier 62 shown in FIG. ₂ being respectively k ₁ = 1 and k ₂ = It is a time response waveform figure when set to 0.7 (an example).

  FIG. 8A shows a waveform 71 (see the broken line) of the disturbance τd of the inertial force received by the actuator 7 when sinusoidal rotational vibration is applied from the outside to the disk device, as in FIG. 6A. The waveform 75 (see solid line) of the disturbance estimation signal τdest output from the disturbance estimator 12 is shown.

The waveform 75 of the disturbance estimation signal τdest is generated by adding a signal obtained by multiplying the integral signal a by k ₁ to a signal obtained by multiplying the proportional signal b advanced in phase by 90 ° by k _2, so that the actual disturbance τd The phase delay with respect to the waveform 71 is smaller than that of the waveform 72 of FIG. 6A in which k ₂ = 0 is set.

  In FIG. 8B, the disturbance estimation signal τdest output from the disturbance estimator 12 obtained in this way is input to the corrector 15, and the disturbance estimation signal τdest is applied to the actuator 7 so as to cancel the fluctuation of the disturbance. The simulation result of the waveform 76 of the position error signal e is shown. Since the disturbance τd can be estimated more accurately than in the case of FIG. 6, the waveform 76 of FIG. 8B is further about ½ times that of the waveform 74 of FIG. The disturbance suppression effect is improved.

  As a result, in the disk device of the present embodiment, the disturbance estimator 12 can accurately detect a disturbance due to an inertial force received by the actuator 7 due to an external impact or vibration, and suppresses a track shift due to the disturbance. The head 2 is positioned and controlled on the target track with high accuracy. Therefore, the disk device according to the present embodiment can perform stable tracking control with respect to impact and vibration, and can improve the reliability of the disk device.

  In the present embodiment described above, the drive signal u output from the block 47 is input as one input signal to the disturbance estimator 12. However, the drive signal u is output from the block 22 instead of the drive signal u. Needless to say, the same effect can be obtained by using the drive current Ia output from the driver.

(Embodiment 2)
FIG. 9 is a block diagram showing a specific configuration of the disturbance estimator 12 included in the disk device according to the second embodiment of the present invention. Note that components having the same functions as those of the block 30 shown in FIG. 2 in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

In the block 30 of FIG. 2, the proportional signal b is multiplied by k ₂ by the multiplier 62 and input to the adder 63. In FIG. 9, the proportional signal b is a high signal whose transfer function is Fb (s). The signal is input to the multiplier 62 through the band cutoff filter 64.

10 shows the disturbance suppression effect of the disturbance estimator 12 of the present embodiment, in which the coefficients k ₁ and k ₂ of the multiplier 61 and the multiplier 62 in FIG. 9 are set to k ₁ = 1 and k ₂ = 1, respectively. FIG. 6 is a time response waveform diagram when the cutoff frequency fb of the high-frequency cutoff filter 64 is set to fb = 500 Hz (one example).

  FIG. 10A shows a waveform 71 (see a broken line) of the inertia force disturbance τd received by the actuator 7 when a sinusoidal rotational vibration is applied to the disk device from the outside, and the disturbance estimation output by the disturbance estimator 12. A waveform 77 (see solid line) of the signal τdest is shown.

  Here, the estimated frequency fo (ωo = 2πfo) and the value of the damping factor ζo are set to 1 kHz and 1 respectively as in the case of FIG. 8, the control band of the position control system is set to 800 Hz, and the disturbance is a frequency of 100 Hz. The simulation was performed as a sine wave with constant amplitude.

  The disturbance estimator 12 estimates the disturbance τd acting on the actuator 7 from the drive signal u which is an input to the driver 10 and the voltage signal Ed output from the voltage detector 11, and the magnitude is slightly large, but the time delay is A disturbance estimation signal τdest almost similar to the actual disturbance τd, which hardly exists, is output.

  FIG. 10B shows a position error signal e when the disturbance estimation signal τdest output from the disturbance estimator 12 is input to the corrector 15 and the disturbance estimation signal τdest is applied to the actuator 7 so as to cancel the fluctuation of the disturbance. The simulation result of the waveform 78 is shown. Even if sinusoidal rotational vibration is applied to the disk device from the outside, the position error signal e hardly varies as shown by the waveform 78 in FIG. 10B by applying the disturbance estimator 12. Further, since the disturbance τd can be estimated more accurately without phase lag compared to the case of FIG. 8, the waveform 78 of FIG. 10B is compared with the waveform 76 of FIG. The disturbance suppression effect is further improved to about 1/3.

  Further, when the disturbance estimator 12 shown in FIG. 9 is used, the high-frequency cutoff filter 60 shown in FIG. 2 is not particularly necessary. The reason for this is that, in FIG. 9, of the signals applied to the adder 63, the integrated signal a is a signal obtained by integrating the deviation signal α by the first integrator 43, and the integrator itself is a kind of high-frequency cutoff filter. Therefore, the signal input to the adder 63 is a signal with less noise from which high frequency components have been removed. On the other hand, since the proportional signal b input to the adder 63 is input via the high frequency cutoff filter 64 of FIG. 9, the disturbance estimation signal τdest synthesized by the adder 63 is also removed from the high frequency component. The signal is less noisy. Therefore, when the disturbance estimator 12 shown in FIG. 9 is used, the high frequency cutoff filter 60 is not particularly necessary in the position control system of FIG.

  As a result, the disk apparatus according to the present embodiment can accurately detect the disturbance received by the actuator 7 by the disturbance estimator 12 and can suppress the track deviation due to the disturbance, so that the head 2 has a target track formed with a narrow track pitch. Positioning control is performed with high accuracy. Therefore, stable tracking control with respect to impact and vibration is possible, and the reliability of the disk device can be improved.

  In the above description, the drive signal u output from the block 47 is input as one input signal to the disturbance estimator 12, but the output of the driver 10 output from the block 22 instead of the drive signal u. It goes without saying that the same effect can be obtained even when the driving current Ia is used.

(Embodiment 3)
FIG. 11 is a block diagram showing a configuration of a disk device according to Embodiment 3 of the present invention. FIG. 12 is a block diagram showing the overall configuration of the head positioning control system in the present embodiment. In addition, about the thing which has the same function as Embodiment 1, the same referential mark is attached | subjected and the overlapping description is abbreviate | omitted.

  In the present embodiment, the difference from the first embodiment in FIG. 1 is the signal input to the disturbance estimator 16. That is, in the first embodiment, the voltage signal Ed generated by the voltage detector 11 and the drive signal u are input to the disturbance estimator 12. However, in the present embodiment, the voltage detector 11 generates The voltage signal Ed to be output and the position control signal c generated by the position controller 14 are input to the disturbance estimator 16. That is, the position control signal c is used in place of the drive signal u.

  The disturbance estimation signal τdest generated by the disturbance estimator 16 of FIG. 11 is input to the corrector 15. The corrector 15 receives the position control signal c output from the position controller 14 and the disturbance estimation signal τdest from the disturbance estimator 16, performs correction calculation, and then outputs the drive signal u to the driver 10.

  A block 80 of the disturbance estimator 16 is a portion 80 surrounded by a one-dot chain line in FIG. The disturbance estimator 16 receives the voltage signal Ed generated by the voltage detector 11 and the position control signal c generated by the position controller 14 represented by the block 21, which is the output of the subtractor 36.

  In FIG. 12, the block 32 and the block 33 together constitute a first multiplier 41. 43 is a first integrator, and 44 is a second multiplier. The block 34 and the block 35 are combined to constitute a second integrator 42.

  The operation of the disturbance estimator 16 in the present embodiment configured as described above will be described with reference to FIGS. 2 and 12 in comparison with the operation of the disturbance estimator 12 of the first embodiment.

  First, in FIG. 2, if the input of the second integrator 42 constituting the disturbance estimator 12 of the first embodiment is γ, the signal γ pays attention to the adder 38 and the subtractor 31,

と表現できる。ここで、簡単のために高域遮断フィルタ６０は接続せず、（数６）と（数１２）が成立するものとする。

Can be expressed as Here, for the sake of simplicity, it is assumed that the high-frequency cutoff filter 60 is not connected and (Equation 6) and (Equation 12) hold.

  By the way, the drive signal u is expressed by (Equation 22) focusing on the adder 46 in FIG.

したがって、（数２１）および（数２２）より、信号γは、（数２３）で表わすことができる。

Therefore, from (Equation 21) and (Equation 22), the signal γ can be expressed by (Equation 23).

（数２３）をもとにして、図２に示す実施の形態１の外乱推定器１２のブロック３０を書き換えると、図１２に示す外乱推定器１６のブロック８０のようになる。図１２に示すように、位置制御器１４（ブロック２１）の生成する位置制御信号ｃが乗算器３２に入力され、乗算器３２の出力は乗算器３３に入力されている。このため、位置制御信号ｃに係数（ｇmn・Ｋtn）を乗算することにより駆動トルク推定信号τestを求めることができる。

If the block 30 of the disturbance estimator 12 of the first embodiment shown in FIG. 2 is rewritten based on (Equation 23), the block 80 of the disturbance estimator 16 shown in FIG. 12 is obtained. As shown in FIG. 12, the position control signal c generated by the position controller 14 (block 21) is input to the multiplier 32, and the output of the multiplier 32 is input to the multiplier 33. Therefore, the drive torque estimation signal τest can be obtained by multiplying the position control signal c by a coefficient (gmn · Ktn).

  On the other hand, the disturbance estimation signal τdest is input to the corrector 15 represented by block 47. Therefore, as in the first embodiment, the disturbance estimator 16 works to reduce the disturbance τd acting on the arm 3 from the voltage signal Ed generated by the voltage detector 11 and the position control signal c generated by the position controller 14. The disturbance estimation signal τdest is output. The disturbance estimation signal τdest is input to the corrector 15 so as to cancel the disturbance τd acting on the arm 3.

  As a result, the disturbance estimator 16 accurately detects the disturbance τd received by the actuator 7 and controls to cancel the disturbance τd using the disturbance estimation signal τdest. As in the first embodiment, the disturbance τd acts as if it was added to the positioning control system through the filter having the cutoff frequency characteristic of (Equation 19) and FIG. At frequencies below the angular frequency ωo, disturbances can be suppressed by the first-order low-frequency cutoff characteristics, and track deviations due to disturbances can be suppressed, so that the head 2 is positioned and controlled with high accuracy on a target track formed with a narrow track pitch. The Therefore, stable tracking control with respect to impact and vibration is possible, and the reliability of the disk device can be improved.

Furthermore, in the present embodiment, when the coefficient k ₁ is set to k ₁ = 1, the coefficient of the block 61 is 1 in FIG. 12, and as a result, the block 61 becomes unnecessary. Further, the coefficient of the block 81 is 0, and only the proportional signal b through the multiplier 82 is input to the subtractor 31, and the block 81 and the adder 83 can be omitted. A form in which the blocks are omitted is shown in FIG.

  By reducing the number of multipliers and adders in this way, circuit adjustment can be simplified when the position control system is realized by hardware such as an analog circuit. Further, when the position control system is realized by software, it is possible to reduce the calculation time delay due to the calculation processing.

(Embodiment 4)
FIG. 14 is a block diagram showing another configuration example of the disturbance estimator 16 constituting the disk device according to the fourth embodiment of the present invention. Note that components having the same functions as those in the block 80 shown in FIG. 11 are given the same reference numerals, and redundant descriptions are omitted.

The following points are different from the block 80 shown in FIG. In FIG. 12, the deviation signal α is multiplied by g 1 by the second multiplier 44 to generate the proportional signal b, and further multiplied by k _{2 by the} multiplier 62 and input to the adder 63. On the other hand, in FIG. 14, the proportional signal b generated by multiplying the deviation signal α by g 1 by the second multiplier 44 is multiplied by the multiplier 62 via the high-frequency cutoff filter 84 whose transfer function is Fb (s). Enter. In FIG. 12, the multiplier 82 multiplies the proportional signal b by (1−k ₂ ) and inputs it to the adder 83. On the other hand, in FIG. 14, the multiplier 85 multiplies the proportional signal b by (1−k ₂ · Fb (s)) and inputs it to the adder 83.

  Further, when the disturbance estimator 16 shown in FIG. 14 is used, the high-frequency cutoff filter 60 as shown in FIG. 12 is not particularly necessary. The reason for this is that in FIG. 14, of the signals applied to the adder 63, the integral signal a is a signal obtained by integrating the deviation signal α by the first integrator 43, and the integrator itself is a kind of high-frequency cutoff filter. Therefore, the signal input to the adder 63 is a signal with less noise from which high frequency components have been removed. On the other hand, since the proportional signal b input to the adder 63 is input via the high-frequency cutoff filter 84 of FIG. 14, the high-frequency component is also removed from the disturbance estimation signal τdest synthesized by the adder 63. The signal is less noisy. Therefore, when the disturbance estimator 16 shown in FIG. 14 is used, the high frequency cutoff filter 60 is not particularly necessary in the position control system of FIG.

  As a result, the disk device of the present embodiment can accurately detect the disturbance received by the actuator 7 by the disturbance estimator 16 and suppress the track deviation due to the disturbance, so that the head 2 is positioned with high accuracy on the target track. Be controlled. Therefore, stable tracking control with respect to impact and vibration is possible, and the reliability of the disk device can be improved.

Further, in the present embodiment, when the coefficient k ₁ is set to k ₁ = 1, the coefficient of the block 61 is 1 in FIG. 14, and as a result, the block 61 becomes unnecessary. Further, the coefficient of the block 81 is 0, and only the proportional signal b is supplied to the subtractor 31 via the multiplier 85, so that the block 81 and the adder 83 can be omitted. A form in which the blocks are omitted is shown in FIG.

  By reducing the number of multipliers and adders in this way, circuit adjustment can be simplified when the position control system is realized by hardware such as an analog circuit. Further, when the position control system is realized by software, it is possible to reduce the calculation time delay due to the calculation process.

The four embodiments have been described above. Next, consider the relationship between the coefficient k ₂ of the coefficient k ₁ and a multiplier 62 of the multiplier 61. The disturbance τd and the disturbance estimation signal τdest are vectors and can also be expressed as complex numbers.

  The relationship between complex numbers and their argument will be described with reference to FIG. The argument θ of the complex number z = x + ji (j is an imaginary unit) is

次に、図１７に基づいて外乱τdに対する外乱推定信号τdestの位相ずれの関係を説明する。

Next, the relationship of the phase shift of the disturbance estimation signal τdest with respect to the disturbance τd will be described with reference to FIG.

With respect to (Equation 18) representing the disturbance estimation signal τdest when k ₁ = 1 and k ₂ = 0, the phase delay θ1 with respect to a certain angular frequency ωd (= 2π · fd) of the disturbance τd is obtained.

となる。これは、基礎的技術の外乱推定器の場合の位相遅れ（符号はマイナス）を示すもので、

It becomes. This indicates the phase lag (sign is minus) in the case of the basic technology disturbance estimator,

とした場合である。

This is the case.

Next, in the present invention in which neither of the coefficients k ₁ and k ₂ is zero, (Equation 4) and FIG. 2 or FIG.

となる。ところで、一般に、

It becomes. By the way, in general,

である。したがって、 複素数ｚ1から複素数ｚ2までの改善角θ２は、複素数（ｚ2／ｚ1）の偏角に相当する。（数１６）、（数１７）の関係を利用して、改善角θ２を求めると、

It is. Therefore, the improvement angle θ2 from the complex number z1 to the complex number z2 corresponds to the deflection angle of the complex number (z2 / z1). Using the relationship of (Equation 16) and (Equation 17), the improvement angle θ2 is obtained.

外乱τdに対する外乱推定信号τdestの位相遅れをゼロにするには、（数２５）、（数３１）の比較により、係数ｋ₁，ｋ₂の比を、

In order to make the phase lag of the disturbance estimation signal τdest with respect to the disturbance τd zero, the ratio of the coefficients k ₁ and k ₂ is calculated by comparing (Equation 25) and (Equation 31).

とすればよい。このとき、外乱推定信号τdestの位相は外乱τdの位相と一致する。すなわち、外乱推定信号τdestは、外乱τdをきわめて正確に推定したものとなる。

And it is sufficient. At this time, the phase of the disturbance estimation signal τdest matches the phase of the disturbance τd. That is, the disturbance estimation signal τdest is obtained by estimating the disturbance τd very accurately.

When the control band of the control system is, for example, 800 Hz, the estimated frequency fo (ωo = 2πfo) of the second-order lag system is set to, for example, 1 kHz which is greater than 800 Hz, and the frequency fd (ωd = 2πfd) of the disturbance τd is set to 100 Hz. In this case, the ratio between the coefficients k ₁ and k ₂ is

となる（一例）。このとき、外乱推定信号τdestの位相は外乱τdの位相と一致する。

(Example). At this time, the phase of the disturbance estimation signal τdest matches the phase of the disturbance τd.

  The disturbance estimator 12 and the disturbance estimator 16 configured as the block 30 in FIG. 2 and the block 80 in FIG. 12 are not affected by the sampling frequency of the sector servo of the disk device. Therefore, the control band of the disturbance estimator can be set higher than the control band of the positioning control system.

The four embodiments have been described above. This apparent as the feature of the present invention, the integrated signal a to k ₁ factor signal, the phase to generate an addition to the disturbance estimation signal τdest 90 degrees proceeds signal proportional signal b obtained by _doubling k I Thus, the phase delay of the disturbance estimation signal τdest with respect to the actual disturbance τd is brought close to zero. As a result, it is possible to sufficiently compensate for disturbances such as bearing friction, elastic force, and inertial force applied to the actuator, and as a result, the fluctuation of the disturbance acting on the actuator during the following operation toward the target track is large. However, this can be canceled out sufficiently effectively, and the positioning control of the head to the target track can be performed stably.

  The technology described so far can be advantageously applied to control of loading / unloading of the head with respect to the disk. Hereinafter, an embodiment in the case of load / unload control will be described.

(Embodiment 5)
The fifth embodiment of the present invention corresponds to a technique in which the technique of the disturbance estimator of the first embodiment is applied to head load / unload control.

  FIG. 18 is a block diagram showing a configuration of a disk device according to Embodiment 5 of the present invention. In addition, about the thing which has the same function as Embodiment 1, the same referential mark is attached | subjected and the overlapping description is abbreviate | omitted.

  The present embodiment is different from the first embodiment in the following points. The position detector 13 and the position controller 14 in the case of FIG. 1 are not provided, and a speed controller 17 is provided instead. Reference numeral 9 denotes a ramp block as a head retracting member disposed outside the occupied area of the disk 1, and 3 a a suspension tab provided at the tip of the arm 3. The suspension tab 3 a slides with the tab holding surface on the ramp block 9 as the arm 3 rotates.

The speed controller 17 generates a speed control signal s from the speed command signal vr and the voltage signal Ed from the voltage detector 11. That is, the speed error signal e ′ is obtained from the speed command signal and the voltage signal Ed.
e = vr-Ed
After performing amplification and phase compensation, the speed control signal s is output. The voltage signal Ed includes speed information. The corrector 15 a receives the speed control signal s from the speed controller 17 and the disturbance estimation signal τdest from the disturbance estimator 12, performs correction calculation, and then inputs the drive signal u to the driver 10. The driver 10 supplies a drive current Ia to the drive coil 5 in accordance with the input drive signal u, rotates the arm 3 around the bearing 4, and rotates the head 2 attached to the tip of the arm 3. Let When the arm 3 is rotated to the outer peripheral side of the disk 1, the head slider is unloaded by placing the suspension tab 3 a of the arm 3 on the tab holding surface of the ramp block 9.

  Next, the operation of the speed control system of the present embodiment will be described with reference to FIG. FIG. 19 is a block diagram showing the overall configuration of the speed control system in the present embodiment. Compared with FIG. 2 in the case of the first embodiment, there is no integrator block 25, there is a comparator corresponding to the position detector 13 instead of the comparator 20, and a voltage including speed information which is an output of the block 36. The signal Ed is fed back to the comparator 13. In the comparator 13, the difference between the speed command signal vr and the voltage signal Ed is taken as a speed error signal e '.

  The speed controller 17 represented by the block 21 a performs the filtering process of the transfer function Gv (s) on the speed error signal e ′, generates a speed control signal s, and inputs it to the adder 46. The speed control signal s becomes the drive signal u via the adder 46. A disturbance τd acting on the arm 3 such as sliding friction between the tab holding surface on the ramp block 9 and the suspension tab 3 a can be expressed as being input to the front stage of the block 24 by the comparator 29. Others are the same as in the first embodiment. The configuration of the block 30 of the disturbance estimator 12, which is the main part, is the same as that in the first embodiment.

Here again, as in the case of the first embodiment, the integral signal a from the first integrator 43 is multiplied by k ₁ by the multiplier 61 and the proportional signal b from the second multiplier 44 is multiplied by k by the multiplier 62. _doubled, by adding the results in the adder 63 so as to generate a disturbance estimation signal Taudest. This addition brings the phase of the disturbance estimation signal τdest closer to the disturbance τd.

  The disk device of the present embodiment can accurately detect the magnitude of disturbance due to friction or the like by a disturbance estimator, and can perform stable speed control even if the fluctuation of the disturbance on the ramp block is large. The reliability of the load / unload operation can be improved.

  In the present embodiment described above, the drive signal u output from the block 47 is input as one input signal to the disturbance estimator 12. However, the drive signal u is output from the block 22 instead of the drive signal u. Needless to say, the same effect can be obtained by using the driving current Ia output from the driver.

  Further, the block 30 of the disturbance estimator 12 may be configured to have a high-frequency cutoff filter 64 as shown in FIG. 9 of the second embodiment.

(Embodiment 6)
The sixth embodiment of the present invention corresponds to a technique in which the technique of the disturbance estimator of the third embodiment is applied to head load / unload control.

  FIG. 20 is a block diagram showing the configuration of a disk device according to Embodiment 6 of the present invention. FIG. 21 is a block diagram showing the overall configuration of the control system in the present embodiment. In addition, about the thing which has the same function as Embodiment 5, the same referential mark is attached | subjected and the overlapping description is abbreviate | omitted.

  In the present embodiment, the difference from the fifth embodiment is a signal input to the disturbance estimator. That is, in the fifth embodiment, the voltage signal Ed generated by the voltage detector 11 and the drive signal u are input to the disturbance estimator 12. However, in the present embodiment, the voltage detector 11 generates The voltage signal Ed to be generated and the speed control signal s generated by the speed controller 17 are input to the disturbance estimator 19.

  The disturbance estimation signal τdest generated by the disturbance estimator 19 in FIG. 20 is input to the corrector 15a. The corrector 15 a receives the speed control signal s output from the speed controller 17 and the disturbance estimation signal τdest from the disturbance estimator 19, performs correction calculation, and then outputs the drive signal u to the driver 10.

  21 is a block diagram of the disturbance estimator 19 in a portion surrounded by a one-dot chain line in FIG. The disturbance estimator 19 receives the voltage signal Ed generated by the voltage detector 11 and the speed control signal s generated by the speed controller 17 represented by the block 21, which is the output of the subtractor 36.

  The disturbance estimator 12 of the fifth embodiment is as follows. The signal obtained by multiplying the coefficient (g 2 / s) of the block 43 of the first integrator and the signal obtained by multiplying the coefficient (g 1) of the block 44 of the second integrator are added to the adder 38. Add with. A signal obtained as a result of the addition and a drive torque estimation signal τest obtained by multiplying the coefficient (gmn · Ktn) of the block 41 of the first multiplier are input to the subtractor 31. The signal γ obtained by subtraction by the subtractor 31 is input to the block 42 of the second integrator. That is, since the drive signal u to which the correction signal β is added is input to the disturbance estimator 12, the adder 38 in FIG. 19 is required.

  However, since the disturbance estimator 19 of the present embodiment is configured to input the speed control signal s before the correction signal β is added, the adder 38 as shown in FIG. 19 is unnecessary. The configuration of the block 80 of the disturbance estimator 19 which is the main part is the same as that of the third embodiment shown in FIG. The use of the multipliers and adders 83 of the blocks 81 and 82 is the same as in the third embodiment.

  The operation of the disturbance estimator 19 in the present embodiment configured as described above will be described with reference to FIGS. 19 and 21 in comparison with the operation of the disturbance estimator 12 of the fifth embodiment.

The operation of the disturbance estimator 19 is the same as that in the third embodiment. Here again, the integral signal a by the first integrator 43 is multiplied by k ₁ by the multiplier 61, the proportional signal b by the second multiplier 44 is multiplied by k ₂ by the multiplier 62, and the results are added to the adder. The disturbance estimation signal τdest is generated by adding at 63. This addition brings the phase of the disturbance estimation signal τdest closer to the disturbance τd.

  The disturbance estimation signal τdest is input to the corrector 15a so as to cancel the disturbance τd acting on the arm 3 such as sliding friction between the tab holding surface on the ramp block 9 and the suspension tab 3a. As a result, the disk device according to the present embodiment can accurately detect the disturbance τd due to friction or the like, and can realize stable speed control even when the fluctuation of the disturbance on the ramp block is large.

  According to the present embodiment, the number of adders necessary for the configuration of the disturbance estimator 19 and the corrector 15a can be reduced as compared with the disk device of the fifth embodiment. Therefore, the disk apparatus according to the present embodiment can estimate the moving speed v of the head and the disturbance τd due to friction acting as a disturbance on the speed control system with a simpler configuration than the fifth embodiment. Thus, the load / unload speed control of the head can be stably performed.

  Furthermore, in this embodiment, by reducing the number of adders, circuit adjustment can be simplified when the speed control system is realized by hardware such as an analog circuit. Further, when the speed control system is realized by software, it is possible to reduce the calculation time delay due to the calculation processing.

The block 80 of the disturbance estimator 19 may be configured to have a high-frequency cutoff filter 84 as shown in FIG. 14 of the fourth embodiment. Further, as shown in FIGS. 13 and 15, k ₁ = 1 may be set.

In the fifth embodiment and the sixth embodiment, the ratio of the coefficients k ₁ and k ₂ is set so as to satisfy k ₂ / k ₁ = ωo ² / (ωo ² −ωd ² ) in (Expression 32). It is preferable to generate a disturbance estimation signal τdest that is configured to estimate the disturbance τd very accurately.

(Embodiment 7)
Embodiment 7 of the present invention switches between an operation for stably controlling the moving speed of the head during loading and unloading of the head and an operation for positioning the head on a target track formed with a narrow track pitch with high accuracy. It is.

  22 and 23 are block diagrams showing the configuration of the disk apparatus according to the present embodiment. In addition, about what has the same function as Embodiment 5, 6, the same referential mark is attached | subjected and the overlapping description is abbreviate | omitted.

  The disk device shown in FIG. 22 is configured to combine Embodiments 1 and 5 and switch the functions of both embodiments.

  Further, the disk device shown in FIG. 23 is configured to synthesize the third embodiment and the sixth embodiment and switch the functions of both the embodiments.

  These disk devices have a position detector 13 for detecting the position of the head 2, a position controller 14 for generating a position control signal c, and a switch 65. The head 2 reads a position signal recorded in advance on the disk 1 as servo information. The position detector 13 detects the current position of the head 2 based on the position signal read by the head 2 and generates a position error signal e indicating a difference from the target position of the target track. The position controller 14 receives the position error signal e generated by the position detector 13, performs amplification and phase compensation, generates a position control signal c, and outputs it to the switch 65. The speed controller 17 generates a speed control signal s from the speed command signal vr and the voltage signal Ed from the voltage detector 11 and outputs the speed control signal s to the switch 65.

  The switching device 65 receives a speed control signal s generated by the speed controller 17 and a position control signal generated by the position controller 14 in response to a switching command between a load / unload command and a following command input to the control terminal 67. Either c is selected and a control signal c 'is output to the corrector 15a.

  In the case of FIG. 22, the disturbance estimator 12 receives the voltage signal Ed generated by the voltage detector 11 and the drive signal u. In the case of FIG. 23, the disturbance estimator 12 receives the voltage signal Ed generated by the voltage detector 11 and the control signal c ′. The disturbance estimation signal τdest generated by the disturbance estimator 12 is input to the corrector 15a.

  The corrector 15 a receives the control signal c ′ output from the switch 65 and the disturbance estimation signal τdest of the disturbance estimator 12, performs correction calculation by the corrector 15 a, and then sends the drive signal u to the driver 10. Output. The driver 10 energizes the drive coil 5 with a drive current Ia in accordance with the input drive signal u, and rotates the arm 3 around the bearing 4. As a result, when a load / unload command is input as a switching command to the control terminal 67 of the switch 65, the switch 66 of the switch 65 is connected to the terminal a side, and the head 2 is the same as in the fifth and sixth embodiments. Is moved to the target track on the disk 1 at a smooth speed. Further, the head 2 can be smoothly retracted from the disk 1 to the ramp block 9. When a following command is input as a switching command to the control terminal 67 of the switch 65, the switch 66 of the switch 65 is connected to the terminal b side, and the head 2 is positioned and controlled to the target track.

  According to the present embodiment, even if the fluctuation of the disturbance on the ramp block is large when the head is loaded / unloaded, the influence of these disturbances can be canceled by the disturbance estimator 12 and the corrector 15a. Speed control is possible, and the reliability of head loading / unloading operations can be improved. In the following operation of the head, even if bearing friction of the bearing 4 and elastic force such as a flexible printed circuit board act on the actuator 7, the influence of these disturbances can be canceled by the disturbance estimator 12 and the corrector 15a. The head positioning accuracy can be improved.

  In each of the embodiments described above, the multiplier and the integrator have been described as being configured with analog filters, but may be configured with a digital filter. Furthermore, each unit constituting the position control system of each embodiment may be realized by software using a microcomputer.

  The disk device and the disk device control method of the present invention are useful as information recording devices such as an optical disk device and a magneto-optical disk device in addition to a magnetic disk device.

1 is a block diagram showing the configuration of a disk device according to Embodiment 1 of the present invention. 1 is a block diagram showing the overall configuration of a positioning control system according to Embodiment 1 of the present invention. (A) is a block diagram for explaining the disturbance estimation operation of the disturbance estimator according to Embodiment 1 of the present invention, (b) is a block diagram obtained by equivalently converting the block diagram of (a), and (c). Is a block diagram that collectively represents the block diagram of (a). (A) is a block diagram for explaining an operation for suppressing disturbance applied to the disk device according to the first embodiment of the present invention, and (b) is a block diagram obtained by equivalently converting the block diagram of (a). Cutoff frequency characteristic diagram with respect to disturbance applied to the disk device of Embodiment 1 of the present invention (A) is a time waveform diagram of a disturbance estimation signal output by a disturbance estimator when the fluctuations of the disturbance applied to the disk device of Embodiment 1 of the present invention and the coefficients k ₁ and k ₂ are set to 1 and 0, respectively. (B) is a time waveform diagram of the track error when the disturbance estimation signal output from the disturbance estimator is input to the corrector and not input to the corrector. FIG. 4 is a vector diagram showing the phase relationship of each signal waveform for explaining the operation of the disturbance estimator according to the first embodiment of the present invention. (A) is the time waveform of the disturbance estimation signal output by the disturbance estimator when the fluctuations of the disturbance applied to the disk device of the first embodiment of the present invention and the coefficients k ₁ and k ₂ are set to ₁ and 0.7, respectively. FIG. 4B is a time waveform diagram of the track error when the disturbance estimation signal output from the disturbance estimator is input to the corrector to cancel the disturbance fluctuation. Block diagram showing a configuration of a disturbance estimator constituting the disk device according to the second embodiment of the present invention. (A) shows the disturbance estimation when the fluctuation of the disturbance applied to the disk device of the second embodiment of the present invention and the coefficients k ₁ and k ₂ are set to 1 and 1, respectively, and the high cut-off frequency fb is set to 500 Hz. (B) is a time waveform diagram of the track error when the disturbance estimation signal output from the disturbance estimator is input to the corrector to cancel the fluctuation of the disturbance. Block diagram showing the configuration of a disk device according to Embodiment 3 of the present invention. Block diagram showing the overall configuration of the positioning control system of Embodiment 3 of the present invention Block diagram showing a form in which unnecessary blocks are omitted from FIG. Block diagram showing the configuration of a disturbance estimator constituting the disk device according to the fourth embodiment of the present invention. Block diagram showing a form in which unnecessary blocks are omitted from FIG. Diagram showing the relationship between complex numbers and their declination The figure explaining the relationship of the phase shift of disturbance estimation signal τdest with disturbance τd Block diagram showing the configuration of a disk device according to Embodiment 5 of the present invention. Block diagram showing the overall configuration of the speed control system of the fifth embodiment of the present invention Block diagram showing a configuration of a disk device according to Embodiment 6 of the present invention. Block diagram showing the overall configuration of the speed control system of the sixth embodiment of the present invention Block diagram showing the configuration of a disk device according to a seventh embodiment of the present invention. Block diagram showing another configuration of the disk device according to the seventh embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magnetic disk 2 Magnetic head 3 Arm 3a Suspension tab 4 Bearing 5 Drive coil 6 Stator 7 Actuator (actuator means)
9 Lamp block (head retracting member)
10 Drive (drive means)
11 Voltage detector (voltage detection means)
12, 16 Disturbance estimator (disturbance estimation means)
13 Position detector (position detection means)
14 Position controller (position control means)
15, 15a Corrector (correction means)
17 Speed controller (speed control means)
32, 33 First multiplier (first multiplication means)
43 First integrator (first integrating means)
44 Second multiplier (second multiplication means)
34, 35 Second integrator (second integrating means)
37 Comparator (Comparison means)
u driving signal c position control signal v head moving speed e position error signal s speed control signal vr speed command signal Va voltage signal v head moving speed vest speed estimation signal τ driving torque τd disturbance τdest disturbance estimation signal Ia driving current Iaest estimated current Ea Induced voltage Eaest Induced voltage estimation signal Vaest voltage estimation signal β correction signal c ′ control signal Ed voltage signal Edest voltage estimation signal a integrated signal b correction signal

Claims (33)

Actuator means for positioning the head relative to the disk;
Driving means for the actuator means;
Voltage detection means for detecting a voltage generated in driving the actuator means and outputting a voltage signal;
Disturbance estimation means for estimating the magnitude of disturbance applied to the head from the drive signal and the voltage signal in the drive means, and generating a disturbance estimation signal;
Position detecting means for generating a position error signal corresponding to the current position of the head from servo information recorded in advance on the disk and detected by the head;
Position control means for generating a position control signal corresponding to the position error signal;
A disk device comprising correction means for synthesizing the drive signal from the position control signal and the disturbance estimation signal,
The disturbance estimation means includes:
A comparison means for comparing the voltage estimation signal generated by the disturbance estimation means with the voltage signal and outputting a deviation signal;
Adding means for adding the signal obtained by multiplying the integral signal obtained by integrating the deviation signal by the first coefficient and the signal obtained by multiplying the proportional signal proportional to the deviation signal by the second coefficient to generate the disturbance estimation signal; A disk device comprising: Actuator means for positioning the head relative to the disk;
Driving means for the actuator means;
Voltage detection means for detecting a voltage generated in driving the actuator means and outputting a voltage signal;
Disturbance estimation means for estimating the magnitude of disturbance applied to the head from the drive signal and the voltage signal in the drive means, and generating a disturbance estimation signal;
Position detecting means for generating a position error signal corresponding to the current position of the head from servo information recorded in advance on the disk and detected by the head;
Position control means for generating a position control signal corresponding to the position error signal;
A disk device comprising correction means for synthesizing the drive signal from the position control signal and the disturbance estimation signal,
The disturbance estimation means includes:
A comparison means for comparing the voltage estimation signal generated by the disturbance estimation means with the voltage signal and outputting a deviation signal;
Filter means for cutting off a high frequency component of a proportional signal proportional to the deviation signal and generating a filter output signal;
And adding means for adding the signal obtained by multiplying the integrated signal obtained by integrating the deviation signal by the first coefficient and the signal obtained by multiplying the filter output signal by the second coefficient to generate the disturbance estimation signal. A disk unit. The disturbance estimation means includes:
A comparison means for inputting a voltage signal detected by the voltage detection means;
First multiplication means for multiplying the drive signal by a coefficient comprising a first transfer function;
Second multiplication means for multiplying the output of the comparison means by a coefficient comprising a second transfer function;
First integrating means for integrating the output of the comparing means;
Second integrating means for integrating a value obtained by subtracting an added value of the output of the second multiplying means and the output of the first integrating means from the output of the first multiplying means;
The comparison means is configured to compare the output of the second integration means with the voltage signal and output the difference to the second multiplication means and the first integration means. The disk device according to claim 1 or 2. Actuator means for positioning the head relative to the disk;
Driving means for the actuator means;
Voltage detection means for detecting a voltage generated in driving the actuator means and outputting a voltage signal;
Position detecting means for generating a position error signal corresponding to the current position of the head from servo information recorded in advance on the disk and detected by the head;
Position control means for generating a position control signal corresponding to the position error signal;
Disturbance estimation means for estimating a magnitude of disturbance applied to the head from the position control signal and the voltage signal and generating a disturbance estimation signal;
A disk device comprising correction means for synthesizing the drive signal from the position control signal and the disturbance estimation signal,
The disturbance estimation means includes:
A comparison means for comparing the voltage estimation signal generated by the disturbance estimation means with the voltage signal and outputting a deviation signal;
Adding means for adding the signal obtained by multiplying the integral signal obtained by integrating the deviation signal by the first coefficient and the signal obtained by multiplying the proportional signal proportional to the deviation signal by the second coefficient to generate the disturbance estimation signal; A disk device comprising: Actuator means for positioning the head relative to the disk;
Driving means for the actuator means;
Voltage detection means for detecting a voltage generated in driving the actuator means and outputting a voltage signal;
Position detecting means for generating a position error signal corresponding to the current position of the head from servo information recorded in advance on the disk and detected by the head;
Position control means for generating a position control signal corresponding to the position error signal;
Disturbance estimation means for estimating a magnitude of disturbance applied to the head from the position control signal and the voltage signal and generating a disturbance estimation signal;
A disk device comprising correction means for synthesizing the drive signal from the position control signal and the disturbance estimation signal,
The disturbance estimation means includes:
A comparison means for comparing the voltage estimation signal generated by the disturbance estimation means with the voltage signal and outputting a deviation signal;
Filter means for cutting off a high frequency component of a proportional signal proportional to the deviation signal and generating a filter output signal;
And adding means for adding the signal obtained by multiplying the integrated signal obtained by integrating the deviation signal by the first coefficient and the signal obtained by multiplying the filter output signal by the second coefficient to generate the disturbance estimation signal. A disk unit. The disturbance estimation means includes:
A comparison means for inputting a voltage signal detected by the voltage detection means;
First multiplying means for multiplying the position control signal by a coefficient comprising a first transfer function;
Second multiplication means for multiplying the output of the comparison means by a coefficient comprising a second transfer function;
First integrating means for integrating the output of the comparing means;
Second integrating means for integrating a value obtained by subtracting an added value of the output of the second multiplying means and the output of the first integrating means from the output of the first multiplying means;
The comparison means is configured to compare the output of the second integration means with the voltage signal and output the difference to the second multiplication means and the first integration means. The disk device according to claim 4 or 5. Said first coefficient (k ₁₎ the ratio between said second coefficient _{(k 2) (= k 2} / k 1) is substantially ^{ωo 2 / (ωo 2 -ωd 2} ) ( however, .omega.o is the estimated disturbance 7. The disk device according to claim 1, wherein the estimated frequency of the means, ωd, is set to be a disturbance frequency). 6. The disk device according to claim 4, wherein the first coefficient is set to be 1. 9. The disk device according to claim 1, wherein a control band of the disturbance estimation unit is set larger than a control band of the position control unit. A position error signal corresponding to the current position of the head is generated from servo information recorded in advance on the disk and detected by the head,
Generating a position control signal corresponding to the position error signal;
Generating a voltage estimation signal that is an estimation of the voltage signal based on a drive signal of the actuator means for positioning the head and a voltage signal generated in driving the actuator means;
Comparing the voltage estimation signal and the voltage signal to generate a deviation signal of the difference,
A disturbance estimation signal is generated by adding a signal obtained by multiplying the integral signal obtained by integrating the deviation signal by a first coefficient and a signal obtained by multiplying a proportional signal proportional to the deviation signal by a second coefficient;
The position control signal and the disturbance estimation signal are combined to generate the drive signal,
A method of controlling a disk device, wherein the actuator means is driven by the drive signal to position the head with respect to the disk. A position error signal corresponding to the current position of the head is generated from servo information recorded in advance on the disk and detected by the head,
Generating a position control signal corresponding to the position error signal;
Generating a voltage estimation signal that is an estimation of the voltage signal based on a drive signal of the actuator means for positioning the head and a voltage signal generated in driving the actuator means;
Comparing the voltage estimation signal and the voltage signal to generate a deviation signal of the difference,
A signal obtained by multiplying the integral signal obtained by integrating the deviation signal by the first coefficient and a filter output signal obtained by blocking the high frequency component of the proportional signal proportional to the deviation signal are added to the signal multiplied by the second coefficient. To generate a disturbance estimation signal,
The position control signal and the disturbance estimation signal are combined to generate the drive signal,
A method of controlling a disk device, wherein the actuator means is driven by the drive signal to position the head with respect to the disk. A position error signal corresponding to the current position of the head is generated from servo information recorded in advance on the disk and detected by the head,
Generating a position control signal corresponding to the position error signal;
Generating a voltage estimation signal that is an estimate of the voltage signal from the position control signal and a voltage signal generated in driving the actuator means;
Comparing the voltage estimation signal and the voltage signal to generate a deviation signal of the difference,
A disturbance estimation signal is generated by adding a signal obtained by multiplying the integral signal obtained by integrating the deviation signal by a first coefficient and a signal obtained by multiplying a proportional signal proportional to the deviation signal by a second coefficient;
The position control signal and the disturbance estimation signal are combined to generate the drive signal,
A method of controlling a disk device, wherein the actuator means is driven by the drive signal to position the head with respect to the disk. A position error signal corresponding to the current position of the head is generated from servo information recorded in advance on the disk and detected by the head,
Generating a position control signal corresponding to the position error signal;
Generating a voltage estimation signal that is an estimate of the voltage signal from the position control signal and a voltage signal generated in driving the actuator means;
Comparing the voltage estimation signal and the voltage signal to generate a deviation signal of the difference,
A signal obtained by multiplying the integral signal obtained by integrating the deviation signal by the first coefficient and a filter output signal obtained by blocking the high frequency component of the proportional signal proportional to the deviation signal are added to the signal multiplied by the second coefficient. To generate a disturbance estimation signal,
The position control signal and the disturbance estimation signal are combined to generate the drive signal,
A method of controlling a disk device, wherein the actuator means is driven by the drive signal to position the head with respect to the disk. Said first coefficient (k ₁₎ the ratio between said second coefficient _{(k 2) (= k 2} / k 1) is substantially ^{ωo 2 / (ωo 2 -ωd 2} ) ( however, .omega.o is the estimated disturbance 14. The disk device control method according to claim 10, wherein the estimated frequency of the means, ωd, is set to be a disturbance frequency). 14. The disk device control method according to claim 12, wherein the first coefficient is set to be 1. 16. The disk device control method according to claim 10, wherein the disturbance estimation control band is set to be larger than the position control control band. Actuator means for loading / unloading the head with respect to the disk;
Driving means for the actuator means;
Voltage detection means for detecting a voltage generated in driving the actuator means and outputting a voltage signal;
Disturbance estimation means for estimating the magnitude of disturbance applied to the head from the drive signal and the voltage signal in the drive means, and generating a disturbance estimation signal;
Speed control means for generating a speed control signal from the speed command signal and the voltage signal;
A disk device comprising correction means for synthesizing the drive signal from the speed control signal and the disturbance estimation signal,
The disturbance estimation means includes:
A comparison means for comparing the voltage estimation signal generated by the disturbance estimation means with the voltage signal and outputting a deviation signal;
Adding means for adding the signal obtained by multiplying the integral signal obtained by integrating the deviation signal by the first coefficient and the signal obtained by multiplying the proportional signal proportional to the deviation signal by the second coefficient to generate the disturbance estimation signal; A disk device comprising: Actuator means for loading / unloading the head with respect to the disk;
Driving means for the actuator means;
Voltage detection means for detecting a voltage generated in driving the actuator means and outputting a voltage signal;
Disturbance estimation means for estimating the magnitude of disturbance applied to the head from the drive signal and the voltage signal in the drive means, and generating a disturbance estimation signal;
Speed control means for generating a speed control signal from the speed command signal and the voltage signal;
A disk device comprising correction means for synthesizing the drive signal from the speed control signal and the disturbance estimation signal,
The disturbance estimation means includes:
A comparison means for comparing the voltage estimation signal generated by the disturbance estimation means with the voltage signal and outputting a deviation signal;
Filter means for cutting off a high frequency component of a proportional signal proportional to the deviation signal and generating a filter output signal;
And adding means for adding the signal obtained by multiplying the integrated signal obtained by integrating the deviation signal by the first coefficient and the signal obtained by multiplying the filter output signal by the second coefficient to generate the disturbance estimation signal. A disk unit. The disturbance estimation means includes:
A comparison means for inputting a voltage signal detected by the voltage detection means;
First multiplication means for multiplying the drive signal by a coefficient comprising a first transfer function;
Second multiplication means for multiplying the output of the comparison means by a coefficient comprising a second transfer function;
First integrating means for integrating the output of the comparing means;
Second integrating means for integrating a value obtained by subtracting an added value of the output of the second multiplying means and the output of the first integrating means from the output of the first multiplying means;
The comparison means is configured to compare the output of the second integration means with the voltage signal and output the difference to the second multiplication means and the first integration means. The disk device according to claim 17 or 18. Actuator means for loading / unloading the head with respect to the disk;
Driving means for the actuator means;
Voltage detection means for detecting a voltage generated in driving the actuator means and outputting a voltage signal;
Disturbance estimation means for estimating the magnitude of disturbance applied to the head from the speed control signal and the voltage signal and generating a disturbance estimation signal;
Speed control means for generating the speed control signal from a speed command signal and the voltage signal;
A disk device comprising correction means for synthesizing the drive signal from the speed control signal and the disturbance estimation signal,
The disturbance estimation means includes:
A comparison means for comparing the voltage estimation signal generated by the disturbance estimation means with the voltage signal and outputting a deviation signal;
Adding means for adding the signal obtained by multiplying the integral signal obtained by integrating the deviation signal by the first coefficient and the signal obtained by multiplying the proportional signal proportional to the deviation signal by the second coefficient to generate the disturbance estimation signal; A disk device comprising: Actuator means for loading / unloading the head with respect to the disk;
Driving means for the actuator means;
Voltage detection means for detecting a voltage generated in driving the actuator means and outputting a voltage signal;
Disturbance estimation means for estimating the magnitude of disturbance applied to the head from the speed control signal and the voltage signal and generating a disturbance estimation signal;
Speed control means for generating the speed control signal from a speed command signal and the voltage signal;
A disk device comprising correction means for synthesizing the drive signal from the speed control signal and the disturbance estimation signal,
The disturbance estimation means includes:
A comparison means for comparing the voltage estimation signal generated by the disturbance estimation means with the voltage signal and outputting a deviation signal;
Filter means for cutting off a high frequency component of a proportional signal proportional to the deviation signal and generating a filter output signal;
And adding means for adding the signal obtained by multiplying the integrated signal obtained by integrating the deviation signal by the first coefficient and the signal obtained by multiplying the filter output signal by the second coefficient to generate the disturbance estimation signal. A disk unit. The disturbance estimation means includes:
A comparison means for inputting a voltage signal detected by the voltage detection means;
First multiplying means for multiplying the position control signal by a coefficient comprising a first transfer function;
Second multiplication means for multiplying the output of the comparison means by a coefficient comprising a second transfer function;
First integrating means for integrating the output of the comparing means;
Second integrating means for integrating a value obtained by subtracting an added value of the output of the second multiplying means and the output of the first integrating means from the output of the first multiplying means;
The comparison means is configured to compare the output of the second integration means with the voltage signal and output the difference to the second multiplication means and the first integration means. The disk device according to claim 20 or 21, wherein: Said first coefficient (k ₁₎ the ratio between said second coefficient _{(k 2) (= k 2} / k 1) is substantially ^{ωo 2 / (ωo 2 -ωd 2} ) ( however, .omega.o is the estimated disturbance The disk apparatus according to any one of claims 17 to 22, wherein the estimated frequency of the means, ωd, is set to be a disturbance frequency). The disk apparatus according to claim 20 or 21, wherein the first coefficient is set to be 1. 25. The disk apparatus according to claim 17, wherein the speed control means generates a speed control signal from a speed command signal and a speed estimation signal generated by the disturbance estimation means. . 26. The disk device according to claim 17, wherein a control band of the disturbance estimation unit is set larger than a control band of the speed control unit. Generate a speed control signal corresponding to the speed command,
A voltage estimation signal that is an estimation of the voltage signal is generated based on a drive signal of the actuator means for loading / unloading the head and a voltage signal generated in driving the actuator means,
Comparing the voltage estimation signal and the voltage signal to generate a deviation signal of the difference,
A disturbance estimation signal is generated by adding a signal obtained by multiplying the integral signal obtained by integrating the deviation signal by a first coefficient and a signal obtained by multiplying a proportional signal proportional to the deviation signal by a second coefficient;
Combining the speed control signal and the disturbance estimation signal to generate the drive signal;
A method of controlling a disk device, comprising: driving the actuator means with the drive signal to load / unload the head with respect to the disk. Generate a speed control signal corresponding to the speed command,
A voltage estimation signal that is an estimation of the voltage signal is generated based on a drive signal of the actuator means for loading / unloading the head and a voltage signal generated in driving the actuator means,
Comparing the voltage estimation signal and the voltage signal to generate a deviation signal of the difference,
A signal obtained by multiplying the integral signal obtained by integrating the deviation signal by the first coefficient and a filter output signal obtained by blocking the high frequency component of the proportional signal proportional to the deviation signal are added to the signal multiplied by the second coefficient. To generate a disturbance estimation signal,
Combining the speed control signal and the disturbance estimation signal to generate the drive signal;
A method of controlling a disk device, comprising: driving the actuator means with the drive signal to load / unload the head with respect to the disk. Generate a speed control signal corresponding to the speed command,
Generating a voltage estimation signal that is an estimate of the voltage signal based on the speed control signal and a voltage signal generated in driving the actuator means;
Comparing the voltage estimation signal and the voltage signal to generate a deviation signal of the difference,
A disturbance estimation signal is generated by adding a signal obtained by multiplying the integral signal obtained by integrating the deviation signal by a first coefficient and a signal obtained by multiplying a proportional signal proportional to the deviation signal by a second coefficient;
Combining the speed control signal and the disturbance estimation signal to generate the drive signal;
A method of controlling a disk device, comprising: driving the actuator means with the drive signal to load / unload the head with respect to the disk. Generate a speed control signal corresponding to the speed command,
Generating a voltage estimation signal that is an estimate of the voltage signal based on the speed control signal and a voltage signal generated in driving the actuator means;
Comparing the voltage estimation signal and the voltage signal to generate a deviation signal of the difference,
A signal obtained by multiplying the integral signal obtained by integrating the deviation signal by the first coefficient and a filter output signal obtained by blocking the high frequency component of the proportional signal proportional to the deviation signal are added to the signal multiplied by the second coefficient. To generate a disturbance estimation signal,
Combining the speed control signal and the disturbance estimation signal to generate the drive signal;
A method of controlling a disk device, comprising: driving the actuator means with the drive signal to load / unload the head with respect to the disk. Said first coefficient (k ₁₎ the ratio between said second coefficient _{(k 2) (= k 2} / k 1) is substantially ^{ωo 2 / (ωo 2 -ωd 2} ) ( however, .omega.o is the estimated disturbance The disk device control method according to any one of claims 27 to 30, wherein the estimated frequency of the means, ωd, is set to be a disturbance frequency). 31. The disk device control method according to claim 29 or 30, wherein the first coefficient is set to be 1. The disk device control method according to any one of claims 27 to 32, wherein a control band for the disturbance estimation is set to be larger than a control band for the position control.

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