KR860001126B1 - Reel motor control apparatus - Google Patents

Abstract

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Description

Rail Motor Control

1 is a circuit diagram of the present invention.

2 is a waveform diagram of the present invention.

3 is a characteristic curve of the present invention.

4 is a conventional circuit diagram and characteristic curves.

* Explanation of symbols for main parts of the drawings

1: frequency detector 2: timer

3: oscillator 4: counter

5: Oagate 6: latch circuit

7: Code Converter 8: Digital / Analog Converter

9: driving motor of real motor 10: first signal converter

11: second signal converter 12: information converter

RM: Real Motor N: Rotational Speed

T: Torque

The present invention provides a video signal recording and reproducing apparatus, comprising: a device for controlling a real motor such that the coercive force of the video tape does not exceed a prescribed value between the pinch roller and the takeup reel of the video tape. It is about.

In the conventional video signal recording and reproducing apparatus, the control of the real motor is performed so that the coercive force of the video tape does not exceed the prescribed value between the pinch roller which compresses the video tape to the capstan rotating at constant speed and the take-up of the video tape. The real motor and the resistor were connected in series to a constant voltage supply device.In this case, when a constant voltage is supplied between one end of the real motor and the end of the resistor, power loss occurs due to the resistance, requiring a large starting torque. Since the starting torque is lowered in the other modes and the pressure of the pinch roller must be relatively high in order to increase the allowable coercive force of the video tape on the take-up side, the capstan motor also takes a large side pressure, which is an important factor in selecting the capstan motor ( To adjust the rotational speed There was a disadvantage that it will act as a) to.

The present invention has been invented to solve the above problems, the frequency pulse of the frequency detector and the frequency of the oscillator in order to drive the real motor with the rotational speed of the real motor and the required torque in the playback mode of the video signal recording and reproducing apparatus When the pulse is supplied to the M ₁ bit counter, such a signal is latched into the latch circuit as an M ₁ bit digital signal within a certain time and supplied to the code converter, and the code converter uses the ideal torque rate curve for the ideal motor. Determination of driving speed

The configuration, operation, and effect of the present invention will be described in detail with reference to the accompanying drawings.

The present invention connects a timer (2) for delaying a pulse of frequency (fg) to a frequency detector (1) for generating a pulse of frequency (fg) proportional to the rotational speed of the real motor (RM). A counter 4 is connected to the counter 2, and an oscillator 3 for outputting a pulse of a frequency fs higher than the frequency fg of the frequency detector 1 is connected to the input side of the counter 4, and a counter is provided. On the output side of (4), a latch circuit 6 for latching the digital input signal by the output signal of the oragate 5 is connected, and the latch circuit 6 connects the M ₁ bit digital input signal to the M ₂ bit. A code converter 7 is connected to an output signal to determine a drive voltage supplied to the real motor RM according to the ideal torque speed curve CS, and the code converter 7 is converted into an analog signal. Digital to Analog Converter (8) with Analog Converter (8) Has a structure in which the real motors RM are connected to each other via the drive circuit 9 of the real motor.

Reference numeral 10 denotes the first signal converter, 11 the second signal converter, 12 the information converter, N the rotational speed, and T the torque.

In the present invention, when the real motor is driven during the playback mode of the video signal recording and reproducing apparatus (VTR), the real rotation state of the video tape is analyzed, and then the rotation speed and the required torque of the real motor are calculated to correspond to the real mower. The supply voltage of the rotor is varied.

On the other hand, the relationship between the torque of a real motor and the coercive force of a video tape is as follows.

Tm = Tc + RTt... … … … … … … … … … … … … … … … … … (One)

Where Tm is the torque of the real motor, Tc is the load torque of the take-up oil, Tt is the coercive force of the take-up oil, and R is the radius of the tape immersion in the take-up oil.

In addition, since the torque of the real motor in the DC motor is determined by a variable of the voltage (V) supplied to the real motor and the number of rotations (n) of the take-down oil, the general equation is used.

Tm = f (n, v)... … … … … … … … … … … … … … … … … … … (2)

It becomes

Therefore, in order to make the coercive force (Tt) of the tape-seiling day constant in Equation (1), the torque Tm of the real motor must be varied. In the equation (2), the voltage V is varied so that the real motor If you achieve the control objective of, that is, change the formula (1),

(Tm-Tc)………………………………………(3)Tt =

(Tm-Tc)... … … … … … … … … … … … … … … (3)

If you differentiate this,

(△Tm-Tc)-

(Tm-Tc)=0…………(4)ΔTt =

(△ Tm-Tc)-

(Tm-Tc) = 0... … … … (4)

(4) must be satisfied.

The video signal recording and reproducing device has a constant unwinding speed of the video tape.

(R

)=R

+

=C……………………(5)

(R

) = R

+

= C… … … … … … … … (5)

는 테이크-엎 리일의 회전각, C는 비데오 테이프의 풀림속도(8㎜인 경우 1.4345㎝/sec)로 나타난다.It becomes

Is the angle of rotation of the take-up rail, C is the unwinding speed of the video tape (1.4345 cm / sec for 8 mm).

Also

R = td.nt... … … … … … … … … … … … … … … … … … … … It becomes (6).

Where td is the thickness of one sheet of video tape. nt represents the number of turns of the tape wound on the take-up day.

And if you differentiate (6) with respect to time,

=td

=td.n………………………………(7)로 되고,

= td

= td.n... … … … … … … … … … … … (7)

=W=2πn, (∵

=2π. nt)……………………(8)로 된다.

= W = 2πn, (∵

= 2π. nt)… … … … … … … … (8).

Therefore, substituting equation (7) (8) into equation (5)

(R

)=R

+(2π. nt)td.n

(R

) = R

+ (2π.nt) td.n

+(2π. nt)td×

= R

+ (2π.nt) td ×

+(nt. td)

= R

+ (nt. td)

= 2R

= 4πRn = C = Constant

……………………………(9)로 된다.∴Rn = Cl where Cl =

… … … … … … … … … … … It becomes (9).

On the other hand, from (4)

=

+(

)

…………(10)이 계산되어진다.

=

+ (

)

… … … … (10) is calculated.

Friction torques were the main loads due to the change of the load torque of the take-up roll according to the change of the tape-locked radius (R) of the take-up roll and the contact friction between the face and the bottom housing of the video tape.

dTc = (2πrdrtwρμ) r ... … … … … … … … … … … … (11)

Therefore Tc = ^R ₀ 2πr ² ρμtwdr

πR³ρμtw=

πR ³ ρμtw

πρμtw)= KR ³ … … … … … … … … … … … … (12) (K =

πρμtw)

Where μ is the coefficient of friction [in N / g]

ρ is the density [g / cm 3]

tw represents the width of the video tape.

And if you substitute (9) into (12)

………………………………(13) [단 K'=KC₁ ³]Tc = K '

… … … … … … … … … … … … (13) [K '= KC ₁ ³ ]

Differentiate the expression (13) with respect to the rotational speed n of the take-up day.

=-3K'n^-4………………………………(14)

= ^-3 K'n ^-4 ... … … … … … … … … … … … (14)

From equation (9)

=-C₁n^-2…………………………………(15)

= -C ₁ n ^-2 ... … … … … … … … … … … … … (15)

Substituting equations (9), (13), (14) and (15) into equation (10)

Appears as

πρμtw×[

]³ K '= KC ₁ ³ =

πρμtw × [

] ³

…………………………………………(17) ⁼

… … … … … … … … … … … … … … … … (17)

Is changed to

(16) The expression can be solved by using a computer, but ^-4 n wherein n is >> when 1 n ^-1 >> n ^-4 because Neglecting wherein n ^-4 to (解) of formula (16)

Tm. n = constant = C2... … … … … … … … … … … … … … (18)

Appears.

Where the constant C2 is [Tm. It can be determined by finding only one in the sea of n], and can also be found by actual measurement, provided that the take-up treading force (Tt) is defined. In the end, this solution is graphically shown in Figure 3.

FIG. 3 shows the NTV characteristic curve. When the ideal Toco velocity curve CS calculated as a result of the equation (16) and the supply voltage of the real motor are V1 and V2, the NT curve CV1 (CV2) is drawn. . And the maximum speed (Nmax) in the rotational speed (N) means the rotation speed of the rail motor when there is no amount of tape wound on the take-up roll, whereas the minimum speed (Nmin) means that the tape is locked When the volume is maximum, the rotation speed of the real motor is displayed.

Therefore, when the real motor is rotated from the minimum speed (Nmin) to the maximum speed (Nmax) during the playback mode of the video signal recording and reproducing apparatus, the characteristic curve of the real motor (NTV curve) is made to match the ideal toco speed curve (CS). It is possible to drive the take-up suspension with a certain coercive force, but it is difficult to obtain such a real motor (RM), and thus the same effect can be achieved by performing voltage control using a general DC motor. .

On the other hand, Figure 4a is a conventional real motor (RM) control loop, which is a video by the first and second signal converters 10 and 11 when the real motor (RM) is driven in accordance with the reference coercive force In the video signal recording and reproducing apparatus intended to prevent the tape coercive force from exceeding a specified value, the mechanical component and circuit component are increased, and the range of the ideal torque velocity curve CS as the coercive force changes as shown in FIG. 4C. Will be difficult to control.

Therefore, in the present invention, the NTV of the real motor RM which intends to use the ideal torque velocity curve CS in the NT curve CV1 (CV2) calculated by the above equations (1) and (18). In order to realize the characteristic curve, the above-described formula for calculating the rotational speed and the required torque of the real motor is such that the tensioning force of the video base is not exceeded above a prescribed value.

1 is a circuit diagram of the present invention, in which a real motor rotates during reproduction mode of a video signal recording / reproducing apparatus, a pulse having a frequency fg proportional to the rotational speed, such as an encoder pulse, from the rotation of a real motor RM in the drawing. When the output signal of the frequency detector 1 that generates the signal is shown in FIG. 2a and the tape is not wound around the take-up rail, the rotation speed of the rail motor is increased to increase the frequency (fg), and as the tape is gradually locked, the frequency ( fg) is lowered. When the output signal of the medium frequency detector 1 is supplied to the oragate 5 and the timer 2, respectively, the timer 2 outputs a pulse signal as shown in FIG. The timer 2 is a kind of monostable multivibrator that is triggered at the falling portion of the input signal to output a delay signal for a predetermined time.

The output signal of the timer 2 is supplied to the reset terminal RT of the counter 4 and operated as a reset signal. The oscillator 3 oscillates at a frequency higher than the frequency fg of the frequency detector 1. From the oscillation frequency fs is supplied as a pulse as shown in FIG. In this case, if fgm is the frequency fg of the real motor RM which decreases at the rotational speed of the fixed motor RM when the tape is wound up to the take-up rail of the video tape from the oscillator 3, It is preferable to set the frequency fs of Mifgm (M is the count range of the counter 4) because the real motor RM rotates at the minimum speed and counts the maximum at the counter 4. will be.

On the other hand, when the reset signal as shown in the waveform of FIG. 2b and the clock signal as shown in FIG. 2c are supplied to the counter 4, the counter 4 counts the input clock signal for each week or week of the reset signal. When the maximum M ₁ bit is counted, the carry-out signal CO is output, so that the counter 4 outputs the speed data according to the change of the rotational speed of the real motor RM as shown in FIG.

In addition, the velocity data output from the counter 4 is supplied to the latch circuit 6. In the latch circuit 6, the same signal as that of FIG. When the speed is supplied to the clock terminal CK of the latch circuit 6 through the latch, the speed data of the counter 4 is latched, and when the next speed data is input, the latch is latched as described above. In the circuit 6, data as shown in FIG. 2D is stored according to the rotational speed of the rail motor RM as shown in FIG. 2A.

Then, the velocity data, such as 2d, which is latched in the latch circuit 6, is immediately input to the code converter 7. The code converter 7 has the ideal torque of the third degree derived from the equations (1) to (18). It is configured as a ROM or a gate circuit so that the speed curve CS can be realized. That is, since the voltage to be supplied to the real motor varies depending on the amount of tape wound on the take-up rail, the speed motor of the latch circuit 6 generates a rotation torque that matches the ideal torque curve CS. In order to supply voltage (CV ₁ ) and (CV ₂ ) to RM respectively, code conversion is performed from speed data.

In this way, the speed data converted by the code converter 7 becomes M ₂ bits when the speed data of the latch circuit 6 is M ₁ bit, and becomes the _second f diagram, and the converted signal is a digital / analog conversion or 8 As the data is supplied to the motor, the data converted according to the ideal torque curve CS becomes an analog signal and is supplied to the driving unit 9 of the real motor. Accordingly, the real motor RM is applied to the rotational speed and the required torque. It will be driven by the correct NTV curve.

As described above, according to the present invention, the video tape can be wound while maintaining the constant coercive force of the video tape under the condition that the coercive force of the video tape is not exceeded above the prescribed value in the playback mode of the video signal playback device. While the bath can be lengthened longer, the wearability of the peripheral device can be eliminated, and the recorded image quality can be maintained for a long time.

Claims (1)

A frequency detector (1) for generating a pulse of frequency (fg) proportional to the rotational speed of the rail motor (RM) is connected to a timer (2) for delaying the pulse of the frequency (fg). (4) to the input side of the counter (4), while the oscillator (3) for outputting a pulse of a frequency (fs) higher than the frequency (fg) of the frequency detector (1), while connecting the output to the oragate (5) ) And a latch circuit 6 for latching a digital input signal, wherein the latch circuit 6 converts the M ₁ bit digital input signal into an M ₂ bit output signal according to the ideal torque velocity curve CS. A code converter 7 for determining a driving voltage of the real motor RM, and a digital / analog converter 8 for converting the analog signal to an analog signal to the code converter 7; The analog converter 8 carries the drive circuit 9 of the real motor. Real motor control device by connecting each of the real motor (RM).

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