JP2675453B2 - Software servo device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a software servo device, and more particularly to a software servo device used for a servo system of a drum motor or a capstan motor of a camera integrated type 8 mm VTR.

[0002]

2. Description of the Related Art In a conventional software servo device used in a servo system of a camera-integrated 8 mm VTR drum motor, integral phase control is performed in an internal reference mode, that is, in a reproduction mode, as shown in FIG. In the case of the external reference mode, that is, the recording mode, the phase comparison type phase control is performed.

That is, in the recording mode in step S1, first, in step S3, the free-run counter data A and B representing the phase of the Vsync signal and the phase of the PG signal are latched to obtain the phase difference data Te. . Then, in step S5, the constant C equivalent to 6H is added to the phase difference data Te to obtain the phase error data T3, and the clipping process is performed in step S7. Then, in step S9, the measured value data T0 of the period of the FG signal and the clipped phase error data T3 are combined at a ratio of K2: K3a to obtain control data T4.
Ask for.

On the other hand, in the reproduction mode in step S1, first, in step S11, the theoretical value data T1 of the FG signal is subtracted from the calculated value data T0 to obtain data T2. Then, in step S13, the data T2 is added to the immediately preceding phase error data T3 to obtain the phase error data T3. Then, in step S15, the calculated value data T0 and the phase error data T3 are converted into K2:
The control data T4 is obtained by synthesizing at the ratio of K3b.

[0005]

Generally, in a servo system of a small motor such as a drum motor, a load variation factor is large and it is necessary to set a large pull-in range in both the recording / playback modes. In order to secure a large pull-in range in the phase comparison type phase control, the upper limit and the lower limit of the clipping process must be set large. However, on the other hand, if the range of the clipping process is widened, the clipping process cannot be effectively performed, and the performance of the servo system may be sacrificed in the transient state at the time of pulling in. Therefore, the pulling range cannot be increased.

Further, in the servo system of a small motor, it is difficult to obtain sufficient performance because it cannot depend on the moment of inertia in spite of a large load variation factor. Therefore, it is necessary to perform complicated processing such as learning servo in addition to the conventional servo system processing, and for that purpose, it is necessary to simplify the software structure of the servo system as much as possible. However, as described above, it is necessary to perform the clipping process in the external reference mode, and further, in order to obtain the control data T4, the constant multiplied by the error phase data T3 is changed to K3a in the external reference mode and K3b in the internal reference mode. Therefore, the software structure is complicated.

Therefore, a main object of the present invention is to provide a software servo device which can set a large retractable range in which servo can be performed and has a simple software structure.

[0008]

SUMMARY OF THE INVENTION The present invention is a software servo device for controlling a motor by control data obtained by synthesizing measured value data corresponding to the cycle of an FG signal from the motor and phase error data at a predetermined ratio. At
In the internal reference mode, the difference between the theoretical value data of the period of the FG signal and the measured value data is used to perform integration processing to obtain phase error data. In the external reference mode, the external reference signal and the motor output Software for correcting theoretical value data based on phase difference data with a PG signal, and performing phase integration processing using the corrected theoretical value data and measured value data to obtain phase error data. It is a servo device.

[0009]

The measured value data T0 corresponding to the cycle of the FG signal is obtained. In the case of the external reference mode, the constant C is added to the phase difference data Te between the external reference signal and the PG signal, and then the predetermined constant K1 is multiplied, and the data is added to the theoretical value data T1 of the cycle of the FG signal. Then, the corrected theoretical value data T1 is obtained. Then, the corrected theoretical value data T1
And the measured value data T0 are used for integration processing. That is, the difference between the measured value data T0 and the corrected theoretical value data T1 is added to the immediately preceding phase error data T3 to obtain the phase error data T3. Then, the measurement value data T0 and the phase error data T3 are combined at a ratio of K2: K3 to obtain control data T4, and optimization processing is performed.

On the other hand, in the internal reference mode, the theoretical value data T1 and the phase difference data Te are not subjected to arithmetic processing, and the uncorrected theoretical value data T1 and measured value data T0 are used in the same manner as described above. Integral processing, phase error data T3
Ask for. Then, the control data T4 is obtained and an optimization process is performed.

[0011]

According to the present invention, in both the external reference mode and the internal reference mode, since the phase error data is obtained by the integration processing, it is not necessary to perform the clipping processing as in the conventional case. Therefore, the pull-in range can be increased without any trouble in servo processing. Further, since it is not necessary to perform the clipping process and the constant applied to the phase error data can be made constant regardless of the external reference mode and the internal reference mode, the software structure can be simplified.

The above-mentioned objects, other objects, features and advantages of the present invention will become more apparent from the detailed description of the embodiments below with reference to the drawings.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 5, a software servo apparatus 10 of this embodiment is, for example, a camera integrated type 8 mm VTR.
, Which is used for the servo system of the drum motor, and which shares the mechanical control (hereinafter, simply referred to as "mechanical control") 12 and the microcomputer which shares the system control (hereinafter,
(Referred to simply as "syscon") 14. The mechanical controller 12 operates in response to a command from the system controller 14,
The mechanical control 12 has a built-in free-run counter 16 for measuring the cycle of the FG signal, the phase of the PG signal and the phase of the Vsync signal. A PWM (Pulse Width Modulation) signal for controlling the drum motor 20 that rotates the head 18 is output from the mechanical controller 12. The driver 22 outputs a motor voltage according to the PWM signal and supplies it to the drum motor 20. The FG signal and the PG signal from the drum motor 20 are amplified by the FG amplifier 24 and the PG amplifier 26, respectively, and are amplified as the FG pulse and the PG pulse by the mechanical controller 1.
2 is input. Further, the video signal is synchronously separated by the synchronous separation circuit 28, and the Vsync signal is input to the mechanical controller 12 as a pulse. In the mechanical controller 12, FG pulse, P
The count value of the free-run counter 16 is latched according to, for example, the rising edge or the falling edge of the G pulse and the pulse of the Vsync signal, and the cycle of the FG signal, P
Measure the phase of the G signal and the phase of the Vsync signal. In addition, the video signal is input to the video circuit 30 and the amplifier 3
It is amplified by 2 and sent to the head 18.

In operation, the FG interrupt routine of FIG. 1 is executed by the mechanical controller 12 for each FG pulse.
In the step S101, the free run counter 16
Value is captured and latched, and measured value data T0 of the cycle of the FG signal is obtained. The measured value data T0 is data of the difference between the current value and the immediately previous value of the free-run counter 16.

Then, in step S103, it is determined whether the external reference mode or the internal reference mode, that is, the recording mode or the reproduction mode. In the recording mode, the phase difference between the PG signal and the Vsync signal is calculated in step S105, and the phase difference data T3
(= A−B) is obtained. Here, as shown in FIGS. 3 and 4, the Vsync interrupt routine and the PG interrupt routine are also executed by the mechanical controller 12 for each pulse of the Vsync signal and each PG pulse, and the value of the free-run counter 16 is captured and latched. , Vsyn
Data A representing the phase of the c signal and data B representing the phase of the PG signal are obtained.

Then, in step S107, 6H (Head Switching Pulse) is set to Vsync for the phase difference data Te.
A constant C corresponding to the phase to be delayed for the signal) is added, and then the constant K1 is multiplied. The data is added to the theoretical value data T1 obtained in advance to obtain corrected theoretical value data T1. Then, steps S109 and S111
Integrate with. That is, in step S109, the corrected theoretical value data T1 is subtracted from the measured value data T0 to obtain the data T2. In step S111, this data T2 is added to the immediately preceding phase error data T3 to obtain the phase error data T3.

On the other hand, if it is determined in step S103 that the reproduction mode is set, steps S109 and S1 are performed.
In 11, the integration process is performed in the same manner as described above to obtain the phase error data T3. . Theoretical value data T used at this time
1 is theoretical value data T1 previously obtained, not obtained in step S107. Then, regardless of the recording mode and the reproduction mode, both are performed in step S11.
In 3, the control data T4 is obtained. Control data T4
Is obtained by synthesizing the measurement value data T0 and the phase error data T3 at a ratio of constants K1: K2. This control data T4 is output as a PWM signal after being subjected to optimization processing through an amplifier, a filter and the like in step S115. Then, in step S117, the driver 22
Outputs the motor voltage obtained by D / A converting the PWM signal,
It is given to the drum motor 20, and the process is completed.

In this embodiment, K1: K2 = 8: 1, K
By setting 3 = 4, the servo system can be stabilized.
When the above embodiment is used for the servo system of the camera-integrated 8 mm VTR capstan motor, the theoretical value data that is not corrected in the recording mode is used, contrary to the case of the servo system of the drum motor. In the integration mode, in the reproducing mode, the A / D converted ATF error data is quadrupled (K1 = 4) to correct the theoretical value data, and the corrected theoretical value data is used to perform the integration processing.
Servo system can be stabilized. The value of K1 differs depending on each servo system.

[Brief description of the drawings]

FIG. 1 is a flow chart showing an operation from an FG interrupt to integration processing of this embodiment.

FIG. 2 is a flowchart showing an operation from obtaining control data to the end.

FIG. 3 is a flowchart showing an operation from Vsync interrupt to end.

FIG. 4 is a flowchart showing an operation from PG interrupt to end.

5 is a block diagram showing a software servo device that operates according to the flowcharts of FIGS. 1 to 4. FIG.

FIG. 6 is a flowchart showing the operation of the conventional technique.

[Explanation of symbols]

 10 ... Software servo device 12 ... Mechanical controller 16 ... Free run counter 20 ... Drum motor 24 ... FG amplifier 26 ... PG amplifier 28 ... Synchronous separation circuit

Claims (1)

(57) [Claims] 1. A software servo apparatus for controlling a motor according to control data obtained by synthesizing measured value data corresponding to a cycle of an FG signal from the motor and phase error data at a predetermined ratio, in the case of an internal reference mode. , The phase error data is obtained by performing integration processing using the difference between the theoretical value data of the cycle of the FG signal and the measured value data. In the external reference mode, the external reference signal and the PG from the motor are used. The theoretical value data is corrected based on the phase difference data with the signal, and the phase error data is obtained by performing an integration process using the corrected theoretical value data and the measured value data. , Software servo equipment.