JPH0487586A - Tension controller - Google Patents

Abstract

PURPOSE:To suppress the torque ripple of high frequency by providing an error voltage integration means, which integrates the error voltage between the output signal of a tension detector and the reference signal according to the rotational angle of the rotational angle detector provided on the shaft of a supply reel, and applying it to a motor. CONSTITUTION:This has a rotational angle detector 6 and an error voltage integration means 7. The rotational angle detector 6 is provided on the shaft of a supply reel 2. The error voltage integration means 7 integrates the error signal V1 according to the rotational angle theta of the rotational angle detector 6. For the error voltage integration means 7, if the error signal V1 exists, the absolute value of the integral value continues to increase, and it is supplied to a motor, and the back torque of high frequency caused by the torque ripple or the disturbance in winding is brought about in the motor, and when the error signal V1 becomes zero, the integral value becomes constant. Furthermore, the rotational angle generator 9 generates the rotational angle electrically, obtaining the reference signal of rotation from the rotational angle detector 6, so the rotational angle detector 6 can be made simple in structure, and miniaturized.

Description

[Detailed Description of the Invention] [Summary] The present invention includes a rotation angle detection section provided on the shaft of a supply reel;
An error voltage integrator that integrates an error signal according to the rotation angle of the rotation angle detection section, and a tension control device that applies an output signal of the error voltage integrator to an electric motor, the torque fluctuation having a high frequency exceeding the servo band. can be controlled.

[Industrial application field]

The present invention relates to a tension servo device that controls the tension of a magnetic tape at a constant level by applying back torque to a supply reel during signal recording/reproduction in a magnetic tape device.

The present invention refers to feedback control that suppresses tension fluctuations synchronized with the rotation of the supply reel.

[Conventional technology]

FIG. 9 is a diagram showing a conventional servo tension device.

It should be noted that similar components are represented by the same reference numerals or symbols throughout the plan. The configuration of this figure will be explained.

This diagram shows a magnetic tape 1 on which electric signals are recorded/reproduced in a magnetic tape device, a supply reel 2 that supplies the magnetic tape 1, and a voltage signal V that presses a tension post against the magnetic tape 1 to generate a voltage signal V. , a DC motor 4 whose shaft is supplied to the same shaft as the supply reel 2 and which applies bucktle torque to the supply reel 2 in a direction opposite to the direction in which it rotates; an adder 5 that inverts and adds the voltage signal Vt from the tension detector 3 to the voltage signal vr; and an adder 5 that amplifies the power of the output signal of the adder 5 and sends it to the DC motor 4 to generate back torque. A supply DC motor drive control section 10, a reel rotation detection sensor 11 whose shaft is connected to the same shaft as the supply reel 2, and a capstan that serves as a feeder for running the magnetic tape 1 at a constant speed. 12, a pinch roller 13 which is a rotating roller that presses the magnetic tape 1 onto the capstan 12 and runs it;
It includes a known tension servo device including a magnetic head 14 for recording/reproducing the magnetic tape 1. There are various types of reel rotation detection sensors 11, such as those that have a plurality of holes around a disc and detect the rotation angle using a light emitting/receiving part, reflective sensors, and sensors that use magnets and magnetoresistive elements. It is used to detect abnormalities such as whether the tape is broken or whether the loading is normal or not, and to control the tape speed by applying a servo to the tape counter and FP/RE11.

Next, the operation will be explained. Since the magnetic tape is supplied from the supply reel, the diameter (r) of the magnetic tape wound on the supply reel decreases as the tape is pulled out. Generally, if the tension of magnetic tape 1 is F, back torque T
The relationship T=rXF holds true. The tension F of the magnetic tape 1 is created by fixing the magnetic tape 1 between a capstan 12 and a pinch roller 13. Therefore, as the diameter r of the magnetic tape decreases, it is necessary to decrease the back torque T in order to keep the tension F constant. Because ΔV,=v,-vt=.

When only r becomes smaller, the tension F increases.

Therefore, the tension fluctuation V from the tension detector 3,
is large (ΔV, = V, -Vt < 0, so the armature current of the DC motor 4 decreases, so this back torque T decreases. , ; missing r-) l; 3
Nimuto I: I just starved.

Disturbed winding refers to a state in which the magnetic tape 1 on the supply reel 2 is deviated in one direction perpendicular to the direction of travel and is wound in contact with another structure. In this case, the winding disturbance becomes resistance and acts to increase the tension F of the magnetic tape. In this case, the back torque T
is decreased to keep the tension F constant.

In this way, the tension servo device maintains the tension of the magnetic tape constant and performs recording/reproduction with the magnetic head 14.

[Problem to be solved by the invention]

However, the DC motor 4 of the conventional tension servo device has a plurality of magnetic poles, and if the number of magnetic poles is large, no particular problem will occur, but if the number of magnetic poles is reduced to reduce economic costs, the torque ripple that synchronizes with the rotation speed will occur. arises on its own. This torque ripple has a higher frequency than conventional fluctuations due to changes in the winding diameter of the magnetic tape or irregular winding, and the effect of suppressing the detected fluctuations is significantly reduced. This is because the supply reel 2, DC motor 4, etc. have a moment of inertia, and cannot generate back torque in response to high frequency torque ripple.

Therefore, fluctuations in high frequency components remain in the tension F of the magnetic tape 1, which causes the problem that recording/reproduction on the magnetic helad 14 cannot be performed normally.Therefore, there is a need to improve economic efficiency by downsizing the tension servo device. However, it was causing problems. Furthermore, as a step towards solving the above problem, this high frequency component torque ripple is supplied to the reel 2.
If an attempt is made to accurately detect the rotation angle corresponding to 0 rotation angle, the diameter of the disc of the reel rotation detection sensor 11#P becomes large, which hinders miniaturization and cost reduction.

Therefore, in view of the above problems, it is an object of the present invention to provide a tension servo device capable of feedback controlling high frequency tension fluctuations of a magnetic tape.

[Means to solve the problem]

FIG. 1 is a diagram showing the basic configuration of the present invention. In this figure, in order to solve the above-mentioned problem, a tension servo device includes a rotation angle detection section 6 and an error voltage integration means 7. The rotation angle detection section 6 is provided on the axis of the supply rule 2. The error voltage integrating means 7 integrates the error signal ΔV1 according to the rotation angle θ of the rotation angle detection section 6. Furthermore, the rotation angle detecting section 6 detects a plurality of rotation angles θ1, and divides the period between the rotation angle θ1 and the next rotation angle θ1°1 into a plurality of time intervals to obtain a plurality of rotation angles θil+ 012+ . . . A rotation angle generating section 9 that generates 1θIN is provided.

[For production]

In FIG. 1, according to the tension servo device of the present invention, the error voltage integrating means 7 continues to increase the absolute value of the integrated value when the error signal ΔV1 exists, and is supplied to the electric motor at a high frequency caused by motor torque ripple or winding disturbance. A back torque of ΔV1 is generated in the motor, and the error signal ΔV1
When becomes zero, the integral value becomes constant. Further, since the rotation angle generating section 9 obtains a rotation reference signal from the rotation angle detecting section 6 and generates a rotation angle electrically, the rotation angle detecting section 6 can be made simple in structure and miniaturized.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a diagram showing a tension servo device according to a first embodiment of the present invention. The configuration of this figure will be explained. This diagram shows a magnetic tape 1 that is read and written by a magnetic head 14.
A rotation angle detection unit 6 provided on the shaft of the supply reel 2 that supplies the magnetic tape via a capstan 12 and a pinch roller 13, and a tension voltage Vt and a reference voltage Vr of a tension detector 3 that detects the tension of the magnetic tape 1. an error voltage integrating means 7 which integrates the error voltage ΔV1 formed by the first adder 5 from and a second adder 8 that outputs an output to a DC motor drive unit 10 that drives a coaxial DC motor 4 .

Next, the rotation angle detection section 6 includes a rotation angle generation section 9 and a reel rotation detection sensor 11, which will be described later. FIG. 3 is a diagram showing the rotation angle of the reel rotation detection sensor.

Although the reel rotation detection sensor 11 shown in this figure is a transmission type photointerrupter, it may be a reflection type photointerrupter. The reel rotation detection sensor 11 detects 2n edges of the hole around the disk 11-1 attached to the shaft of the supply reel using a light emitting/light receiving section 11-2. The number of rotations of the disk 11-1 from a certain time when the i-th edge is reached with a certain hole as a reference is expressed as j. Next, the error voltage integrating means 7 in FIG.
A/D (Analog/
a third adder 22 that adds the current input signal from the A/D converter 21 and the cumulatively added input signal up to the previous time;
RAM (Random Access Memo
ry) 23, a latch means 24 that holds the output signal from the RAM 23, and a D/D/D converter that converts the digital signal from the latch means 24 into an analog signal and whose output is connected to the second adder 8. A (Digital/An
alog) converter 25 and the rotation angle θ1 from the rotation angle detection section 6, and based on this rotation angle θ1, the A/D converter 21, the third adder 22, the RAM 23, and the latch means 24 are activated. A timing controller 26 that generates a timing signal to operate, and the timing controller 2
6, the rotation angle θ1 is determined by the error signal ΔV 2 (θi) in cooperation with the read/write R/W signal from the timing controller 26 to the RAM 23.
and a counter 27 for forming an address signal of the RAM 23 so as to be a parameter of the RAM 23. Note that the above configuration can also be realized by a microcomputer software program.

FIG. 4 is a flowchart of error voltage integration.

In this figure, in steps 1.2 right and 3, the RAM 23
ΔV2(θi) is initialized. Next, disk 11-
Error voltage ΔVr=V, -V at the first rotation of 1
, is converted from analog to digital by the A/D converter 21 (step 5). The timing starts with the edge of the rotation angle signal (step 4). The third adder receives the input signal ΔV2(θ,
) and the signal ΔV 2 (θ
, ), the error voltage integral value is ΔV2(θ1)=ΔV2(
θl)+ΔV r (θ1) is calculated.

Next, ΔV2 (θ2) = ΔV 2 (θ2) + Vl (θ2
),...

ΔV 2 (θ2,)=ΔV2(θ2-) +Vl(θ
2. ．． ) are calculated and sequentially written into the RAM 23 (step 6). The error voltage integral value at the j-th rotation of the disk 11-1 is generally as follows (step 6
．． 7).

ΔV 2 (θ1)−gΔV+(θ1)kk, Q (i=1..., 2n) Next, this ΔV2(θi) is passed through the latch means 24 to D/
It is converted from digital to analog by the A converter 25 (step 7), and ΔV1(θ) is added to this ΔV2(θ) (step 8). Here, ΔV+(θ) is added to prevent sudden tension fluctuations, and if this disturbance is removed by other methods, this addition is unnecessary.

FIG. 5 is a diagram showing the relationship between arbitrary rotation angle θ1 and rotation speed J. In this figure, the vertical axis shows the error voltage integral value, and the horizontal axis shows the rotation speed j. Error voltage integral value ΔV at a certain rotation angle θ1
2 (θ,) is the error voltage ΔV r (θ
) continues to increase as long as it is not zero. ΔV2
(θi) is fed back to the DC motor 4, so
As its absolute value increases, the error voltage ΔVI(θ) approaches zero and eventually becomes a constant value.

FIG. 6 is a diagram showing the waveform of the final error voltage integral value ΔV 2 (θ1). This figure shows (a
) represents a pulse detected by the light emitting/light receiving unit 11-2 through the hole in the disk 11-1, rising and falling at the edge of the hole, and the ordinal number of the edge corresponds to the first rotation angle θ1. Book ff
1(b) shows the torque ripple caused by the DC motor 4 that has conventionally occurred. It fluctuates around the target torque T0. B in this diagram (C) is the conventional error voltage ΔV + (θ)
waveform, but it fluctuates depending on the tri-clip. Even if the gain of the DC motor drive section 10 was adjusted in this state, it was difficult to suppress ripples with high frequencies. This figure (
B of C) is the final error voltage integral value ΔV2(θ1
), and the shape of the waveform of the signal fed back to the DC motor 4 changes. Therefore, the torque clip is removed and the torque becomes a constant value T0.

That is, according to the present invention, the moment of inertia of the DC motor 4 can be canceled and high frequency tricripple can be eliminated.

FIG. 7 is a diagram showing a rotation angle signal generator according to a second embodiment of the present invention. In this figure, the rotation angle signal generator 9 is a rising edge detector 3 connected to a reel rotation detector 11.
1 and a reference clock CP obtained by dividing the clock signal of a crystal oscillator as input, and a counter A32 that counts the input and clears the count with the previous rising edge detector 31, and the count data of the counter A32 is divided by 1/N ( = 1/2":
a latch section 34 which latches the data shifted to the lower position by n is the shift amount) and this latched data is cleared by the rising edge detector 31; a counter B35 which inputs the reference clock CP and performs counting; The count is compared with the latch count of the latch section 34, and if they match, the pulse signal is sent to the timing controller 26.
and a digital comparator 36 for outputting to the counter B35 and clearing the count of the counter B35.

FIG. 8 is a diagram showing a time chart of the rotation angle generating section in FIG. 7. This figure a shows the signal from the reel rotation detector 11. This is a signal obtained when the number of holes in the disk shown in FIG. 3 is significantly reduced, for example, when the number of holes is reduced to one. This is a pulse signal when the rising edge detector 31 detects the rising edge of the reel rotation detector 11. This diagram C shows the reference clock as counter A3.
2, which is cleared by the pulse signal of the rising edge detector 31, and the counted value immediately before being cleared is set as α. Since the magnetic tape that is supplied and wound around the reel 2 is very thin, there is no problem in accuracy in generating the rotation angle described later even if the immediately preceding count value is used. FIG. d shows that the setting value of the latch section 34, for example, the value α/4, is set and held until the next edge signal arrives. The figure e shows the count value of the counter 35. This figure f shows that when the count value e of the counter 35 reaches the α/4 value, a pulse signal is generated and the count value of the counter B35 is cleared. In this way, the period of the reel rotation detector is reduced to 1/N, that is, the period between rotation angles θ1 and θi41 is divided into a plurality of equal time intervals, and a plurality of rotation angles θth, θ12, . ..., a virtual rotation angle signal of θi8 can be output. Therefore, the rotation angle detection section 6 can have a simpler structure than the conventional one, and can be made smaller.

〔Effect of the invention〕

As explained above, according to the present invention, error voltage integrating means is provided for integrating the error voltage between the output signal of the tension detector and the reference signal according to the rotation angle of the rotation angle detection section provided on the shaft of the supply reel. Since the voltage is applied to the motor,
It is expected that high frequency torque fluctuations can be controlled.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the principle configuration of the present invention, Fig. 2 is a diagram showing a tension servo device according to the first embodiment of the invention, and Fig. 3 is a diagram showing the rotation angle of the second reel rotation detection sensor. Figure 4 is a flowchart of error voltage integration, Figure 5 is a diagram showing the relationship between error voltage integral value of arbitrary rotation angle θi, J and rotation speed J, and Figure 6 is the final error voltage integral value ΔV 2 ( θiN”)
FIG. 7 is a diagram showing the rotation angle generation section according to the second embodiment of the present invention. FIG. 8 is a time chart of the rotation angle generation section in FIG. 7. FIG. A diagram showing a tension servo device. In the figure, 1... tape, 2... supply reel, 3
...Tension detector, 4...Electric motor, 5...Adder, 6...
Rotation angle detection section, 7...Error voltage integration means, 9...
・Rotation angle generator. Diagram illustrating the principle structure of the present invention.

Claims (1)

[Claims] 1. A supply reel (2) that supplies the tape (1), and a tension detector (2) that detects the tension of the tape (1).
3), and an electric motor (4) coupled to the supply reel (2).
), and the output signal of the tension detector (3) (
Error signal (ΔV) between V_t) and reference signal (V_r)
_1) to the electric motor (4) to adjust the back torque to keep the tension of the tape (1) constant; Department (
6), error voltage integration means (7) for integrating the error signal (ΔV_1) according to the rotation angle (θ) of the rotation angle detection section (6), and an output signal of the error voltage integration means (7). (ΔV_2(θ)
) to the error signal (ΔV_1) and applies this added signal to the electric motor (4). 2. The rotation angle detection unit (6) detects a plurality of rotation angles (θ_i)
is detected, and the rotation angle (θ_i) and the next rotation angle (θ_i
_+_1) is divided into multiple time intervals to create multiple rotation angles (θ_i_1, θ_i_2, ..., θ_i_N).
The tension control device according to claim 1, further comprising a rotation angle generating section (9) that generates a rotation angle.