JPH0283842A - Tape transport device control device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for directly transporting tape (eg, magnetic tape) from reel to reel, and particularly to control of a tape transport device suitable for transporting tape at high speed and with high precision.

[Prior Art] As described in Japanese Patent Application Laid-Open No. 62-252561, a conventional tape transport device measures a tape tension error during a period of accelerating a magnetic tape, and uses the measurement to determine and maintain a correction value. The reel drive motor current command value is corrected in order to control the tape tension to a predetermined value.

[Problems to be Solved by the Invention] The above-mentioned prior art is a method of indirectly correcting the motor current command value using the tape tension measurement value, and the reel, the reel drive motor, the power amplifier therefor, and the tension sensor. ,
Because no consideration is given to variations in the characteristics of mechanical elements such as tapes, these variations can lead to the problem of incorrect motor current command values being set during the calculation process of motor current command values and correction values. there were. moreover,
There is a constraint that the process of calculating the correction value is complicated and the processing time becomes long.

An object of the present invention is to appropriately correct motor drive commands to compensate for variations in characteristics of a reel drive system, thereby enabling stable tape transport.

[Means for solving the problem] The above purpose is to measure the current flowing through each motor during the acceleration/deceleration period of the tape, and calculate the current between this and the current command value for each motor in a state where there is no tape tension error. This is achieved by determining the error and correcting the motor current command values for the two reel drive systems so that the current error is within an allowable value.

[Function] Errors in the characteristics of the two rail drive systems, especially variations in characteristics in transient states during acceleration and deceleration, are a bottleneck in realizing stable tape running, but in the present invention, the tape speed can be adjusted During the acceleration/deceleration period to be changed, the motor current flowing through each motor within this period is measured, and the current error between this and the current command value to each motor in a state where there is no tape tension error is determined. By correcting the next motor current command so that this current error falls within the allowable value, stable tape running can be realized.

[Example] Hereinafter, the present invention will be explained in detail based on specific examples.

FIG. 1 is a block diagram showing an embodiment of a tape transfer device according to the present invention. This device does not have a tape buffer such as a vacuum column, and the reels 4 and 5 are controlled by a motor drive signal determined by a digital controller 10 as described later.
The M drive motor 6°7 is rotated, and the magnetic tape is fed out from one reel, and the magnetic tape is delivered to the magnetic head 2 at a predetermined speed.
, and is wound onto the other reel.

The reel motors 6.7 each have a power ampoule 14.7 consisting of a current amplifier. ．． 15.

The input of the power amplifiers 14 and 15 is the DA converter 1].

12 outputs. The DA converter 11.12 receives the digital signal from the digital controller 10 via the output port 19, converts it into an analog signal, and outputs the analog signal to the power amplifier 1'4.15. Thus, the digital controller 10 controls the motor 6.7, and the magnetic head 2 reads and writes data on the magnetic tape 1.

Appropriate encoders 8 and 9 are attached to the motor 6.7, each of which generates N pulses for each revolution, and sends the signal n1+n2 to the input port 2o of the digital controller 10.The motor 6.7 7 motor current is A/D
The analog signal is sent to the converter 13, which converts the analog signal into a digital signal, and the outputs I, , L are sent to the input port 20 of the digital controller 10.

Tension sensor 3 outputs a measured value of tape tension and sends it to AD converter 13 . The AD converter 13 converts the measured value of tape tension into a digital signal and sends its output f to the input port 20 of the digital controller 1o.

An input port 20 is provided in the digital controller 1o, and signal wires 3, 1□+n sent from the outside are provided in the digital controller 1o.
It receives il n2 and sends it to the arithmetic unit 16.

The computing unit 16 has a function of controlling the entire digital controller 10, and drives the reel motor 6.7 to rotate the reels 4 and 5, thereby increasing the speed of the magnetic tape 1 as it passes through the magnetic head 2. Determine motor drive commands for controlling speed and tension to predetermined target values.

The arithmetic unit 16 stores control parameters necessary for determining the motor drive command in advance in a ROM (RsadOnly Mem) and input data sent from the input port 20.
ory) Calculate using mechanical constants such as motor constants stored in 18. Then, each control parameter that is the output is transmitted to RA and M at appropriate time timings.
(Random Access Memory) 17
and updates the control parameters.

Next, the operation of the apparatus shown in FIG. 1 will be explained using FIG. 2. FIG. 2 is an operation flow diagram showing the operation of the digital controller 10.

First, the process of step FIO in FIG. 2 is performed.

This is a step in which mechanical constants necessary for determining the motor current command are set in the RAM 17 from the ROM 18.

Next, the process proceeds to step F20, where the computing unit 16 calculates the radius r□l r of the tape wound on reel 4 and reel 5,
and the total inertia of motor 6.7 J1. J, (the total inertia applied to the motor by the motor itself, the reel 4°5, the tape wound on it, etc.) is calculated and stored. This radius rll r may be calculated using any algorithm, but here it is calculated as follows. Under the condition that the tape tension is constant, the winding rule 4 is set to 1.
What is the length of tape wound during rotation?

Since it is equal to the length of the tape fed out by the supply reel 5, the following formula (1) holds true. Furthermore, the sum of the tape lengths wound on each reel is constant, and the following formula (2) holds true.

2πr□=2πr2・W...(1)yc
(rl"-ro") + x (r22-ro")
=C, - (2) Here, ri: radius of the tape wound on reel 4 r2: radius of the tape wound on reel 5 Co: constant Solving the two equations (1) and (2), each radius rll r2
can be determined using the count value n2 as a variable, as shown in equations (3) and (4) below.

r□=-i-'r2...(3) Arithmetic unit 1
6 calculates the radius rx+r of each reel by calculating the above equations (3) and (4).

This calculation is performed each time a new count value n2 is determined using the encoder 8.9 pulses input via the input port 20. Constant of ra + Cot N required for this calculation (part of mechanism data)
is stored in the ROM 18 in advance.

Next, using the radii r□ and r2, each motor 6.7
The total inertia of J1. Calculate J. The total inertia J□t Jz of the motor 6.7 can be obtained from the following equation (5).

Jt ”Jat+ −πρw (rt re')
(5) (i=1.2) Calculate J2 and store the result in RA and M17.

This value is updated every time the radius ril r is rewritten.

Next, the process proceeds to step F30, where the motor current command value required to accelerate the tape from a stationary state to the target speed is calculated.
1+I52 is calculated and the result is stored in the RAM 17. The command value Idly Ill is obtained from the following equation (6). The speed vL is obtained from equation (7).

ρ: Tape density W: Tape width The calculator 16 calculates J0□+Jl+□, ρ, and W in the mechanism data stored in advance in the ROM 18.

17o value and radius rz+r2 stored in RAM 17
Using the data of , J engineering is calculated by equation (5).

t (j=1,2)...
(6) Here, i=1: related to motor 6 i=2: related to motor 7 G, : Mechanism gain constant □ ~ 3 gain constant ■, : Speed target value fr: Tension target value vl: Speed Measured value f: Tension measurement value, where tI: Pulse interval time of encoders 8 and 9. However, if i=1, encoder 8. i=2 indicates that it is related to encoder 9.

Iat=GtKx(Vr-Vt)-(a)(i=
1.2) Also, the motor current command value used in step F60.

x+Ioz is calculated using equation (8). This motor current command value. 11 I. 2 is the motor current command value defined by equation (6) only when the tape tension error is zero. ml
I. It's a match for 2.

The arithmetic unit 16 is stored in advance in the ROM 18;
- to, ,v, ,f, ,N, and step FIO.

Result G1 processed by F2O and stored in RAM17
．． G, and the results processed in step F20 and stored in the RAM 17, the respective motor current command values are calculated according to equations (6) to (8). Furthermore, the motor current command value when decelerating the tape from a running state to a stationary state can also be calculated using equations (6) to (8). In this case, the speed command value V is set to a value during deceleration.

Subsequently, the process proceeds to step F40, where the motor current command value I Bx y I Sv is applied to the motor 6.7 to drive the tape. In the following step F50, the motor current I0. of each reel drive system during tape acceleration or deceleration time is determined. I2 is detected and stored in the RAM 17.

Next, the process proceeds to step F60, and the formula (
Motor current command value calculated in 8). 1゜I 02 to F
The motor current measurement value I1.1*2 obtained in the process of 2O is subtracted from each other to calculate the current error ΔIllΔmec2.

Next, the process proceeds to step F70, where the current error Δ■ is calculated,
It is determined whether Δwork exceeds the allowable value. As a result of this judgment, if it is below the allowable value, step F30
Motor current command r Blt I determined by equation (6)
It is determined that gz is a value suitable for tape transport, and no further correction is made. However, if it exceeds the allowable value, the motor current command value is determined to be an inappropriate value for tape transfer, and the mechanical constant used to determine the motor current command value is corrected. Step F
80 processes are performed.

The process of step F80 is a process of correcting and storing the mechanical constant using the motor current measurement values I, I, obtained in step F50. Coefficient ε1 for modifying the mechanism constant. ε2 is obtained by the following formula (9).

(i=1,2) Correction coefficient ε1. E2 is determined for the following reasons. The motor current command values I, □, Is□ calculated by equation (6) in the process of step F30 include tape tension feedback compensation, but the motor current command values I, 0 . I. Not included in 2.

Therefore, when comparing the two, the values will be different if there is a tape tension error. For example, reel tape 5
If the measured value f of the tape tension is larger than the target value f1 when sending the tape from the tape to the reel 4, the motor current command value is set. The value is set larger than 1. This is a result of the feedback compensation to reduce the tension error in equation (6). As a result, the current value of the motor 6 decreases,
The current error Δ11 becomes Δ<0. Motor 6 current command. Since , is a positive value, the correction coefficient ε□ is determined as a value smaller than 1 from equation (9).

In the next tape operation, when calculating the motor current command value, by correcting the mechanism gain constant G□ to a value multiplied by ε□, the mechanism gain constant can be made substantially equal to its original design value. You can get the results you want. The process of deriving the modification coefficient ε has been described above as an example, but the modification coefficient E2 can also be derived by the same steps, so the explanation thereof will be omitted.

Correction coefficient ε1. If the calculation of ε2 is performed during the tape acceleration period or deceleration period, the calculation accuracy is good because the motor current value is large during this period. Furthermore, by increasing the number of samples such as motor current measurement and adding averaging processing, errors introduced in the measurement and calculation process can be reduced.

As described above, the motor current command value for driving the tape transport device is corrected to a value suitable for the actual device. As a result, errors in tape speed and tape tension caused by inappropriate motor current commands can be reduced when transporting the tape.

FIG. 3 is a block diagram showing another embodiment of the invention. In contrast to the configuration shown in FIG. 1, this FIG. The only difference is that the configuration for sending data to port 20 is omitted, and the other configurations are the same.

The operation flow diagram showing the operation of FIG. 3 is different from the flow diagram of FIG. 2 in step F50. In the process of F60, some of the parameters used to calculate the current error Δ111ΔI2 are different. Other processing is the same as the operation flow diagram of FIG.

In this embodiment, the motor current command value defined by equation (6), 1°, □ is used instead of the motor current measurement values I, , I. Therefore, the current error ΔI,.

ΔWork 2 is the motor current command value I81. +I54 to formula (8
) Motor current command value defined by ■. It is obtained by subtracting 1+IO2 respectively. The other operations in the digital controller 10 are the same as those shown in FIG. 2, and a description thereof will be omitted.

In this embodiment, the motor current command value of the tape transport device can be corrected in accordance with the actual device, as in the embodiment shown in FIG. 1, without measuring the motor current. Tension errors can be reduced.

[Effects of the Invention] As explained above, according to the present invention, an appropriate motor current command is determined for each device to compensate for the reel quick-acting system having different characteristics, and the tape is driven using this command. and tension can be stably and accurately corrected by adapting it to the actual device.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a control device showing one embodiment of the present invention, Fig. 2 is an operation flow diagram of the embodiment of Fig. 1, and Fig. 3 is a block diagram of a control device showing another embodiment of the present invention. It is a diagram. l...Magnetic tape 2...Magnetic head 4.5
...Reel 6,7...Motor 8.9...
Encoder 10...Digital controller 11.12...D/A converter 14.15...Power amplifier 16...Arithmetic unit 17...RAM1
8...ROM 19...Output boat 2
0... Input port 3... Tension sensor 13.
・・Representatives of A/D converter: Ko Honda, Hiroshi Hiratani, Futabe

Claims (1)

[Claims] 1. Current commands to motors that drive each reel are based on the diameter of the tape wound on each reel so as to wind the tape unwound from one reel onto the other reel. A control device for a tape transport device that calculates and controls tape acceleration or deceleration includes means for detecting a current flowing through at least one motor during a tape acceleration or deceleration period, and means for calculating a current command for each motor when there is no tape tension error. , means for determining the current error between the detected motor current and the calculated current command, and means for correcting the current commands to the two reel drive motors so that the current error is within a tolerance value. A control device for a tape transport device equipped with.