JPH06187752A - Driving device - Google Patents

Abstract

PURPOSE:To stably drive a driving object at a low speed by adding a vibration component changing at a high frequency to a driving signal. CONSTITUTION:The vibration component S21 changing at a higher frequency than the level change of the driving signal S4 from a disturbance code generator 21 is superposed on the driving signal S4 through an LPF 4 and an amplifier 5 in an adder circuit 22 to become the driving signal S22. Then, the signal S22 is supplied and a transferring motor 7 is driven through a driving circuit 6. The driving object is driven at a low speed stably with the torque of extent exceeding dynamic friction force smaller than static friction force based on the dither constitution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving device, and is preferably applied to a driving device for driving an optical head of an optical disc device for optically recording and / or reproducing information on a disc-shaped recording medium. .

[0002]

2. Description of the Related Art Conventionally, for example, there is a driving device shown in FIG. 4 for driving an optical head of an optical disk device to follow a recording track formed on the optical disk to perform a feeding operation.

That is, in FIG. 4, reference numeral 1 denotes a drive device for driving the optical head as a whole, and a target value signal S1 representing a target value of the optical head position is input to a subtraction circuit 2.
The subtraction circuit 2 includes a photo detector 10 to an amplifier circuit 11
The difference between the tracking error signal S10 of the optical head and the target value signal S1 transmitted via the optical head is calculated, and the calculation result S2 is transmitted to the low-pass filter 4 and the coil drive circuit 8 via the amplifier circuit 3.

The low-pass filter 4 extracts only the low frequency component of the calculation result S2 of the subtraction circuit 2 and integrates it to obtain an integrated output signal S3, which is sent to the drive circuit 6 via the amplifier circuit 5.

The drive circuit 6 controls the drive of the transport motor 7 for transporting the entire transport unit carrying the optical head by following the track of the optical disk. The drive circuit 6 is output from the low-pass filter 4. The carry motor 7 is driven by a data drive signal S5 corresponding to the signal level of the integrated output signal S3.

On the other hand, the coil driving unit 8 includes the subtraction circuit 2
The tracking motor 9 is driven by inputting the calculation result S2 output from the above and outputting the drive signal S7 to the tracking motor 9 based on the calculation result.

Here, the tracking motor 9 is a voice coil motor for finely driving the optical head mounted on the carrying section on the carrying section, and the optical head follows the recording track of the optical disk. Driven to. Thus, the transport unit equipped with the optical head is the transport motor 7
The optical head on the transport section is driven by the tracking motor 9 so that the optical head is driven so as to follow the recording track of the optical disk.

The photodetector 10 is adapted to detect the deviation amount of the irradiation position of the optical head with respect to the recording track, and the tracking error signal S10 from the photodetector 10 is sent to the subtraction circuit 2 via the amplifier circuit 11. Sent out. Therefore, in the subtraction circuit 2, the difference between the target value S1 and the tracking error signal S10 is output as the calculation result S2. As a result, the optical head is servod such that it is driven by the amount of deviation of the optical head from the target value.

Here, when the carry motor 7 is slightly fed, the voltage level V of the drive signal S4 output from the amplifier circuit 5 (FIG. 4) as shown in FIG.
When the voltage level V reaches the minimum starting voltage V1 after the maximum starting voltage V1 of the carrying motor 7 corresponding to the maximum static friction force of the drive system driven by Start, at this time drive signal S
The driving voltage V of No. 4 drops below the minimum starting voltage V1. In this way, the drive voltage of the carry motor 7 changes in a sawtooth shape up to the minimum starting voltage V1 of the carry motor 7.

[0010]

By the way, in this type of driving device, a spiral gear is provided on the output shaft of the conveying motor, and the conveying portion is driven to be conveyed through the gear. In this case, in order to shorten the access time to the optical disc, a method of reducing the gear ratio and feeding the optical head at high speed is used, but if the gear ratio is reduced, the load for driving the transport unit increases, As a result, the minimum starting voltage at which the conveyance motor 7 starts rotating to overcome the maximum static frictional force of the gear portion increases. As a result, the transport amount of the transport unit once started to move becomes large, which makes it difficult to perform fine driving such as low-speed transport of the transport unit, and thus the tracking servo is apt to be disengaged.

Further, when the load fluctuation of the movable part occurs due to the environmental change, etc., the maximum static friction force changes,
There was a problem that the feeding operation of the optical head became unstable. As a result, as shown in FIG. 5B, the minimum starting voltage V1 of the carry motor 7 fluctuates, and the carry amount of the carry section becomes unstable.

The present invention has been made in consideration of the above points, and an object thereof is to propose a driving device which can stably perform minute driving.

[0013]

In order to solve such a problem, according to the present invention, in a drive device 20 for driving an object to be driven through a predetermined drive means 7, the drive signal S4 inputted to the drive means 7 is driven by the drive signal S4. A vibration component S21 that changes at a frequency higher than the level change of the signal S4 is added.

Further, in the present invention, the driving means 7 drives the driven object via the gear formed on the output shaft.

[0015]

By adding the vibration component S21 to the driving signal S4 of the driving means 7, when the driving means 7 overcomes the maximum static frictional force between the driving means 7 and starts driving, the momentum given to the driving object is small. Become. Therefore, the drive amount of the drive target can be reduced.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1 in which parts corresponding to those in FIG. Adder circuit 2
2 is the disturbance signal S21 output from the disturbance code generator 21.
And the drive signal S4 are added, and this is added to the disturbance addition drive signal S
It is sent to the drive circuit 6 as 22.

The drive circuit 6 generates a motor drive signal S25 based on the disturbance addition drive signal S22 and drives the carry motor 7 accordingly.

That is, as shown in FIG.
The disturbance addition drive signal S22 output from the disturbance addition drive signal S2 has a smaller frequency than the drive signal S4 shown in FIG.
1 (FIG. 1) is a superimposed signal waveform.

By driving the carry motor 7 based on the disturbance addition drive signal S22, the drive voltage level of the carry motor 7 reaches the minimum starting voltage V1 of the carry motor 7 while changing in a small cycle.

The minimum starting voltage V1 is determined according to the maximum static frictional force when driving the driven object via the spiral gear provided on the output shaft of the carry motor 7.
When the drive voltage level reaches this minimum starting voltage V1, the carry motor 7 starts to rotate, and the driving voltage level again falls below the minimum starting voltage V1. In this way, the carry motor 7 outputs the disturbance addition drive signal S22 at the minimum starting voltage level V
Every time it reaches 1, it rotates a minute amount.

In the above construction, as shown in FIG. 3B, the torque TQ2 generated when the carry motor 7 is stopped has a large value while having a high frequency change according to the waveform of the disturbance addition drive signal S22. When the torque changes and reaches the maximum static frictional force F1 to be driven by the carry motor 7, the carry motor 7 starts rotating.

At this time, the impulse until the conveyance motor 7 starts to rotate is expressed by the product of the torque TQ2 between the dynamic friction force F2 and the maximum static friction force F1 and the time, so that the torque is different from the conventional one. The impulse is smaller than when TQ1 (FIG. 3A) increases linearly.

Accordingly, when the carry motor 7 starts rotating, the amount of motion given to the object to be driven (the carrying section) also becomes small, so that the amount of rotation of the carry motor 7 and the feed amount of the optical head also become small. Therefore, the carry motor 7 can be finely driven, whereby the optical head to be driven by the carry motor 7 can be finely fed.

According to the above construction, by applying the disturbance signal S21 to the drive signal of the carry motor 7, the carry motor 7 can be finely driven, and by repeating the fine drive, the target drive object can be obtained. It is possible to perform minute feeding (that is, low-speed feeding) of the optical head transport section.

In the above embodiment, the disturbance signal S2
Although the case where a sine wave is used as 1 has been described, the present invention is not limited to this, and a disturbance signal having various waveforms such as a rectangular wave signal can be used. In this case, by changing the duty ratio of the disturbance signal S21, it is possible to change the feed amount of the optical head when the carry motor 7 is driven once.

Further, in the above-described embodiment, the case where the control for repeating the fine driving is performed on the carry motor 7 has been described, but the present invention is not limited to this, and the disturbance signal S21 is not limited thereto.
By increasing the waveform amplitude of the carrier motor 7 so that the carrier motor 7 is finely moved at all times, the carrier motor 7 stably drives the object to be driven with a torque that exceeds a dynamic frictional force smaller than the maximum static frictional force of the drive system. Can be driven at low speed.

Further, in the above-mentioned embodiment, the case where the present invention is applied to the driving device for driving the optical head of the optical disk device has been described, but the present invention is not limited to this, and various other driven objects are driven. The present invention can be widely applied to driving devices that operate.

[0029]

As described above, according to the present invention, the drive signal for driving the drive means is added with the vibration component that changes at a frequency higher than the level change of the drive signal, thereby driving It is possible to realize a driving device that can more stably and minutely drive the means.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a driving device according to the present invention.

FIG. 2 is a characteristic curve diagram showing the drive voltage of the carry motor according to the embodiment.

FIG. 3 is a characteristic curve diagram showing accumulated energy during head drive.

FIG. 4 is a block diagram showing a conventional drive device.

FIG. 5 is a characteristic curve diagram for explaining a problem.

[Explanation of symbols]

1, 20 ... Driving device, 2 ... Subtraction circuit, 4 ... Low-pass filter, 6 ... Driving circuit, 7 ... Conveying motor, 8 ...
… Coil drive circuit, 9… Tracking motor, 10…
... Photo detector, 21 ... Disturbance code generator, 22 ...
… Addition circuit.

Claims (2)

[Claims] 1. A drive device for driving an object to be driven via a predetermined drive means, wherein a vibration component changing at a frequency higher than a level change of the drive signal is added to a drive signal input to the drive means. A drive device characterized by the above. 2. The drive device according to claim 1, wherein the drive means drives the drive target through a gear formed on an output shaft.