JPH0279788A - Apparatus for controlling rotational phase of motor - Google Patents

Abstract

PURPOSE:To improve control characteristics by latching a reference signal, a regeneration control signal and an FG signal in a measuring counter, inputting the signals into a microcomputer, comparing the reference signal with the FG signal, and performing D/A conversion. CONSTITUTION:A measuring counter 11 houses a circuit having a latching function. A reference signal (a), a regeneration control signal (b) (e.g., a frequency signal obtained from running magnetic tape) and an FG signal (c) (e.g., a frequency signal obtained from a capastan for driving the magnetic tape) from the outside are latched and measured. The signals are inputted into interrupting signal terminals INT1-INT3 of a microcomputer 12. The data which are latched with the measuring counter 11 are inputted into the microcomputer 12 through a bus line 13. Then, operation for phase control is performed based on the reference signal and the FG signal. D/A conversion is performed in a D/A converter 14. The result is outputted as a phase comparison output. Thus the phase control characteristic is improved effectively.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention is applicable to, for example, servo control of a capstan motor of a video tape recorder, and a drum motor for controlling the rotational speed and phase of a rotating magnetic head. The present invention relates to a rotation phase control device for a motor for servo control, etc.

(Prior Art) For example, in a home video tape recorder, in order to control the rotational speed and phase of a rotating magnetic head,
A drum servo circuit is provided, and a capstan servo circuit is provided to control the drive speed and phase of the magnetic tape. These servo circuits control the rotation of the drum motor or capstan motor, and control the rotational phase of these motors.

The capstan servo circuit described above is provided with means for detecting the rotational speed of the capstan motor, and this detection means is constituted by a rotation signal generator attached to the rotation shaft of the capstan, and the rotation signal is generated by the rotation signal generator. By controlling the frequency of a rotation detection signal (FC signal) generated by the capstan motor, the rotation speed of the capstan motor is controlled.

Also, during playback, a control signal pre-recorded on the magnetic tape driven by the capstan is played back, and the phase of the playback control signal is the same as that of the phase control system of the drum servo circuit. The rotational phase of the capstan motor is controlled so as to have a predetermined phase with respect to the reference signal.

Here, the above-mentioned control signal is a signal that is recorded in correspondence with the vertical synchronization signal for every frame (two periods of the vertical synchronization signal) of the video signal that is recorded on the magnetic tape during recording. , in the case of the NTSC system, the signal has a frequency of 29.97 Hz. Therefore, the phase control corresponding to the control signal reproduced from the magnetic tape is executed at the frequency of 29°97 Hz in the case of the NTSC system. That is, the control characteristics of the rotational phase of the capstan motor are determined by the frequency of the control signal determined by the standard, and control accuracy cannot be increased any further.

(Problems to be Solved by the Invention) The present invention has been made in view of the above points, and it is possible to effectively improve and improve control characteristics by setting a high sampling frequency for phase comparison. It is an object of the present invention to provide a rotational phase control device for a motor in which the rotational phase of the motor is controlled.

[Structure of the Invention] (Means for Solving the Problems) In the motor rotation phase control device according to the present invention,
a reference signal set for phase control; a first feedback signal corresponding to the rotational movement of the motor, such as a control signal recorded on a magnetic tape driven by the motor; and a rotational speed of the motor. latching the count value of a measurement counter based on each second feedback signal such as a signal from a rotation detector corresponding to a second feedback signal, reading and storing latched data corresponding to each of the signals;
The phase difference between any signal among the first feedback signal and the second feedback signal is measured based on the stored latch data, and the phase difference between this measurement result, the reference signal, and the second feedback signal is measured. Based on the results, the phase difference between the reference signal and the first reference signal is determined, and the rotational phase of the motor is controlled.

(Function) In the motor rotation phase control device as described above, a second feedback signal such as a detection signal from a rotation detector attached to the motor can be used for phase control. Therefore, the sampling frequency of phase control can be made sufficiently higher than conventional methods, and the control characteristics can be effectively improved. Control characteristics such as control can be easily improved.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows its configuration, and this embodiment shows an example in which a capstan motor for driving a magnetic tape in a video tape recorder is controlled. This device includes a measurement counter 11 that counts a predetermined clock signal supplied from the outside, and this measurement counter U is constituted by an up counter.

Further, this total n1 counter 11 has a built-in circuit having a latch function, and latches the current count data using a latch signal supplied from the outside.
A reference signal, a reproduction control signal, and a rotation (FC) signal are supplied to the measurement counter 11 as latch signals.

Here, the above-mentioned reference signal is generated from an oscillator or the like as a rotation reference for the motor, and the reproduction control signal is reproduced from a magnetic tape driven by a capstan driven by a capstan motor to be controlled. This signal is recorded in correspondence with the vertical synchronizing signal for each frame of the video signal recorded on the magnetic tape, and is used as the first feedback signal. Further, the FG multiplied signal, for example, a signal obtained from a rotation detector attached to the capstan in response to the rotation of the capstan, is used as a second feedback signal.

The reference signal, reproduction control signal, and FG double signal are each supplied as a latch signal to the latch function of the measurement counter 11 as described above, and are also supplied as an interrupt command to the interrupt manual inputs INTI to INT3 of the microcomputer 12, respectively. Ru.

The measurement counter 11 and the microcomputer 12
is connected to the pass line 13, :lal
The data latched by the counter 11 is stored in a storage mechanism such as RAM of the microcomputer 12, and the microcomputer 12 executes calculations for phase control. The calculation result is outputted to the pass line 13, converted into an analog phase comparison output by the A/D conversion circuit 14, and outputted, so as to be used for controlling the rotational phase of the capstan motor.

That is, when various latch signals such as those described above are manually input to the total Δp1 counter 11, the count contents of the total/1-1 counter 11 corresponding to the arrival time of each latch signal are temporarily latched and stored by the latch function. At the same time, an interrupt command is issued to microcomputer +2. When the microcomputer 12 interrupts in response to this interrupt command, the counter 11 latched by the latch function
The =1 value is read out, and arithmetic processing begins to be executed.

2 to 4 show the microcomputer 12 using the reference signal, reproduction control signal, and FC signal, respectively.
This shows the state of interrupt processing in . First, the interrupt processing for the interrupt terminal lNTl by the basic signal is performed in the second step.
Illustrated in the diagram. When interrupting by this reference signal, first in step 111, the data (NVP) latched by the latch command by this reference signal is read.

Then, in the next step 112, reference data (REF) is set, and the value of this reference data REF is given by the following equation.

REF-NVP+N, ・・・・・・・・・・・・・・・
...(1) (Here, No is the phase control target value)
Then, the control output is obtained such that the difference between the latch data and the data NCTL corresponding to the arrival time of the reproduction control signal becomes the target value N, and the value of the reference data REF is computer 12
It is stored in the internal RAM.

FIG. 3 shows the interrupt terminal IN of the microcomputer 12,
This shows the flow of interrupt processing by the reproduction control signal for T2. In step 121, data (NCTL) latched by the reproduction control signal is read, and in step 122, the latched data is stored in the RAM. Then, in the next step 123, the reference data R stored in the processing of the interrupt INTI by the reference signal is
Based on EF.

It is stored in RAM as quasi data CREF.

In this state, as explained in the above INTI processing process, the latch data NCTL is generated by the reproduction control signal.
Although it is possible to calculate the difference between the reference data REF and the reference data REF and take it out as the control output, in this embodiment, the output is generated only for each FC signal, and the above-mentioned No output processing is performed.

After the reference data CREF is stored in the RAM in step 123, a flag FCTL indicating that the reproduction control signal has arrived is set to "1" in the next step 124, and this process is ended.

Figure 4 shows the interrupt terminal INT of the microcomputer 12.
This figure shows the flow of interrupt processing by the FG double signal for No. 3. First, in step 131, the latch data NFC by the FG double signal is read, and in the next step 132, the flag FCT is read.
Determine whether L is "1". If it is determined that this flag FCTL is "1", the process proceeds to step 133. This flag FCTL being "1" means that the first F after the reproduction control signal arrives.
This indicates that the G-times signal has arrived, and the above step! 3
In 3, the reference data CREF set by the INT2 interrupt
Perform the process to set it again. That is, by adding the phase difference of the FG multiplied signal that arrived first after the arrival of the reproduction control signal to the reference data, the phase control target is converted from the reproduction control signal to the FC signal, and new reference data is obtained. Here, this newly set reference data CREF is given by the following equation.

CREF-CREF+NFG-NCTL・・・・・・
(2) After the process of step 133 is completed, or if it is determined that the flag FCTL is "0" in step 132, the process proceeds to step 134.

In this step 134, the phase difference is calculated, and as shown in FIG.
If the latch data by the FC signal that arrives first after the arrival of is NFGI, and the latch data by the subsequent FG multiplied signals are sequentially NFGI, NFG3, NFG4, then F
The calculation of the phase difference corresponding to each G-times signal is as follows. Here, the calculation results of NFGI-NFG4 are assumed to be XI, X2, x3, and X4, respectively.

XI Zen (NCTL NVP-No)・・・・・・
...(3) X2-(NCTL-NVP-No) 10(NFG2-N
FGI -Nl) ・・・・・・・・・(4) X3= (NCTL-NVP-No)+(NFG3-
NFGI -2Nl)・・・・・・・・・ (5)
) +(NFG4 -NFGI -3Nl)...
(6) Nl in the above equations (4) to (6) is caused by resetting the reference value CREF in step 13G, which will be described later, and becomes the target value data for the FG multiplied signal period. .

That is, the second in each of the above equations (4) to (6)
The term is ``when the period of the FC signal matches the target value.
0", and if the FG double signal period deviates from the target value, the value corresponds to the amount of deviation, and the FG
It can now be used as an output for controlling the cycle of the C signal to a target value.

Step 135 is the upper S self (3
) to (6) are output to the D/A conversion circuit 12 as phase comparison outputs, and the next step 13B is to reset the reference data CREF as described above. Execute the process that performs. Then, in step 137, the flag FCTL is set to "0" and this process is ended.

In this embodiment, the frequency of the FC signal is set to be four times that of the reproduction control signal CTL, but this ratio may be set as appropriate, especially when the frequency is an integer multiple. It doesn't have to be.

That is, in the above-mentioned device, the rotational phase difference of the motor is detected by the interruption by the FG double signal that is generated at a sufficiently shorter period than the reproduction control signal, and the rotational phase control of the motor is executed. Become. Such a phase comparison operation is improved as follows compared to the conventional one, and the transfer function G(S) in this phase comparison circuit is given by the following equation.

G (S)=A (1-e-”)/5-==-(7)
(A is DC gain) The gain and phase of the above equation (7) are given by the following equation.

l G (S) I = AT (sin (ω
T/2)/(ωT/2)・・・・・・・・・(8) ZG
(S)-ωT/2・・・・・・・・・・・・・・・
(9) In the above equations (7) to (9), T indicates the sampling period in the phase comparator circuit, and in the conventional case, it is T-1/29.97. On the other hand, in the case of the example, T-1/ (29,97X4) is obtained, so the position II obtained by the above formula (9)
Depending on the characteristics, the phase delay in the phase comparator circuit is 4
It will move to twice the higher frequency.

Therefore, the gain of the phase control loop in the above embodiment can be made sufficiently higher than that of the conventional one, and the control characteristics can be effectively improved.

In the above embodiment, control of the capstan motor of a video tape recorder is shown as an example, but this can also be applied to other examples, such as phase control of a drum motor of a video tape recorder. It can be implemented with various modifications such as.

[Effects of the Invention] As described above, according to the motor rotation phase control device according to the present invention, it becomes possible to replace the feedback signal from the phase controlled object with the feedback signal from the speed controlled object, thereby improving the phase control. Control characteristics are effectively improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram illustrating a motor rotational phase control device according to an embodiment of the present invention, and FIGS. 2 to 4 are flowcharts illustrating the flow of interrupt processing for a microcomputer in the embodiment device, respectively. FIG. 5 is a time chart illustrating the operating state of the above device. 11...Measurement counter (including latch function), 12.
...Microcomputer, 13...Pass line, 1
4...D/A conversion circuit. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2 1NT2 1NT3 4th day

Claims (1)

[Claims] A reference signal serving as a reference for the rotational phase of the motor, a first feedback signal obtained from means for detecting a phase corresponding to the rotational operation of the motor, and a rotational signal corresponding to the rotational frequency of the motor. a measurement counter configured to obtain latched data by a second feedback signal generated at a sufficiently shorter period than the first feedback signal from the means for detecting the reference signal; means for setting and storing reference data based on the obtained latch data; means for setting and storing control data based on the latch data obtained in response to the generation of the first feedback signal; means for setting and storing rotational phase data based on latch data obtained in response to the generation of a feedback signal; and setting new reference data based on the difference between the control data stored and the rotational phase data. and a means for calculating phase difference data corresponding to the difference between the new reference data set by this means and the rotational phase data stored and set, and obtaining information using the calculated phase difference data. A rotational phase control device for a motor, characterized in that the rotational phase of the motor is controlled based on a phase comparison result.