JPS62204459A - Tape driving device - Google Patents

Abstract

PURPOSE:To stabilize a tape speed control system keeping a loop gain in the control system constant, and to obtain a tape speed control device with high performance, by providing a gain correcting means in which the system becomes stable in the tape speed control system. CONSTITUTION:In the titled device, the number of reference oscillation pulses is counted corresponding to the output pulse period of each of rotary detectors 4S and 4T, and as the outputs of counters 6S and 6T, digital values NS and NT corresponding to the rotating periods of both reels S and T, can be obtained, and the outputs NS and NT are inputted to an adder 7, then an output (NS+NT) being obtained. At a subtractor 9, the output (NS+NT) of the adder 7 is subtracted from a reference value Nref outputted from a reference value generator 8, and a result Nref-(NS+NT) is outputted to a D/A converter 10. A computing element 11 performs an arithmetic operation based on a value N with regard to the diameter of a reel T, and a gain adjuster 12 outputs a signal inputted from the D/A converter 10 to a filter 13. And a signal Err through the filter 13 is inputted to a reel T driving circuit 14, then the rotating speed of a reel T 1 being controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a tape drive device that controls the transport of a long object such as a magnetic tape using a supply reel and a take-up reel. The present invention relates to a tape drive device that controls almost constant speed transfer.

Conventional technology Conventionally, fast forwarding of a magnetic tape in a magnetic recording/reproducing device,
In the tape winding method during rewinding, the rotational speed of the take-up reel driving motor is controlled to be approximately constant. For this reason,
The tape transport speed differs greatly between the beginning and end of magnetic tape winding, which has caused various problems. Therefore, in the 1970s,
As shown in Publication No. 32207, the supply reel (hereinafter referred to as SIJ-le) rotation period Ts0, the take-up reel (
There is a method of keeping the tape transport speed approximately constant by detecting the rotation period TT i (hereinafter referred to as 'l' IJ-ru) and controlling the T reel drive motor so that the sum TS+TT of both reel periods is constant. be.

Problems to be Solved by the Invention However, when the conventional method described above is applied to a tape drive device, the T to be controlled according to the diameter of the 'l' I7-
When configuring a tape speed control system due to changes in the reel rotation speed, the parameters are not constant from the beginning to the end of tape winding, making it extremely difficult to configure a stable tape speed control system and difficult to put into practical use. there were.

The present invention has been made in view of this point, and uses a method of keeping the tape transport speed substantially constant by keeping the sum of both the S reel rotation period Ts and the TIJ reel rotation period TT constant Ts+T7'i. The purpose of this invention is to provide a method for configuring a stable control system for a tape drive device.

Means for Solving the Problems In order to solve the above problems, the present invention provides detection means for detecting the T reel rotation period 'rT and the S reel rotation period Ts;
A first arithmetic processing means for calculating the difference between the reference value and Ts + TT, a T reel driving means, inputting a signal obtained from the first arithmetic processing means and outputting a control signal for controlling the T reel driving means. and a second arithmetic processing means that calculates the reciprocal 17G,f of the open loose gain GA of the first arithmetic processing means and controls the gain of the gain variable means.

According to the above-described configuration, the present invention corrects the change in loop gain of the tape speed control system due to the change in the T reel control rotation speed using the variable gain means, and when the tape is being transported, the T reel is
A tape speed control system having the same characteristics even when the reel diameter changes can be constructed, and a stable control system can be constructed.

Embodiment FIG. 1 is a block diagram showing an embodiment of the tape drive device of the present invention. In Figure 1, 1 is T reel, 2 is S reel
Reel 3 is being transported by tape in the direction of the arrow. 4s
is S reel rotation detector, 4T is T reel rotation detector, 6
is a reference oscillator that outputs a pulse with a period of Tc, 6s, 6
T uses the output pulse of the reference oscillator 6 as an input clock, and the reset pulse is sent to the S reel rotation detector 43. T!
7 is an adder for adding up the values obtained by the counters 63 and 6T; 8 is a reference value generator; 9 is a reference value Nr e f
A subtracter for subtracting the output value of adder 7 from 5 to
9 constitutes a first calculation processing means for calculating the difference between the reference value and TS+'l°T. 10 is a digital-to-analog converter c (hereinafter referred to as a D/A converter) that converts the digital signal output from the subtracter 9 into an analog signal; 11
12 is a gain adjuster that varies the gain according to the value of the calculator 11; 13 is a filter; and 14 is a T-reel drive circuit.

The present embodiment will be explained below based on FIG.

In FIG. 1, when both reels rotate and the tape is transferred, pulses with periods Ts and TT are sent to the counters 6S and 6.
Each is input to T. Figure 2 shows counters 6S and 6T.
This is a waveform diagram for explaining the operation of the counter 6B.
, the output of 6T is S.

A digital value Ns corresponding to the T-wheel rotation period.

NT is obtained. The respective outputs Ns and NT obtained from the counters 6g and 67 are input to the adder 7, and N B +
Get N7. The subtracter 9 subtracts the output NS+NT of the adder 7 from the reference value Nref output from the reference value generator 8, and outputs this Nr,1-(NB+N7) to the D/A converter 10. The calculator 11, which will be explained in detail later, is for stably operating the control system according to the T-reel rotation speed to be controlled, and performs calculations based on the value N7 related to the T-reel diameter. . Gain adjuster 12
is configured such that its gain is controlled by the output of the arithmetic unit 11, and outputs the signal input from the D/A converter to the filter 13. Then, a signal (Err signal) via the filter 13 is input to the 1'' reel salt motion high path 14, and the rotational speed of the T reel 10 is controlled.

It is well known that if the sum of the rotation periods of both reels is kept constant, the tape speed will be approximately constant.If the configuration shown in Figure 1 is adopted as described above, the tape speed V will be lower than the target speed. If it is slow, the output NS+NT of the adder 7 becomes large, the output Nro1-(NB+NT) of the subtracter 9 becomes small, and the T-reel drive circuit 14 operates to increase the rotation speed of the T-reel. Conversely, as the tape speed V increases,
Ns ten NT becomes smaller, Nr, 1-(N3 +N7
) increases, and the rotational speed of the TIJ-le decreases. In the manner described above, the tape speed V is controlled to be substantially constant.

The characteristics of the tape speed control system will be explained below, and the operation of the arithmetic unit 11 will be explained.

Here, if the rotational angular velocity of the T reel is ωT, then T +
) - If the change in rotation angular velocity is ΔωT, then ΔωT
=ωT-(ωτ±ΔωT) Substituting the formula (1), 7"T=5-(TT ΔTT) (However, ΔTT is the change in TI-) "T T (TT ΔTT) □( (K'jTT) As described above, it can be approximated as shown in equation (2).

Next, N 3 and N output by the 1 counters 6B and 67
T can be expressed by equations (3) and (4).

If the change in the digital value output to the D/A converter 1o is ΔN, then IN=(Ns+NT) ((Ns±ΔNS)+(NT
±ΔNT)) (However, ΔNS and ΔNT are counters of 6s,
67 output change) = (ΔNS + ΔN1.)
・・・・・・River/Use song...(5) Also, S, 7 reel radius R8, R7, tape speed V1 both reel rotation angular velocity ω
S and ωT have the following relationship.

v=R8IIω5=RT・ωT ・・・－・・・・・・
...Gate 6) is guided.

FIG. 3 is a diagram showing the input/output characteristics of the D/A converter 1o. In Fig. 3, Nf11a is the maximum value of digital input (for example, in a 5-bit D/A converter, Nma!=
2=256), vfna is the maximum output voltage of the analog output. Therefore, the input/output gain of the D/A converter 1o (
vma! /Nmax) is KD, the analog output change ΔE when the digital input value of the D/A converter changes by ΔN is ΔE−KD・ΔN ・・・・・・・・・・・・・・・
...(9) Substitute equation t5) into equation (9), ΔE = KD - (ΔNs + ΔNT) (3), Substitute equation (4), Substitute equation (8), equation (2) Considering the processing from blocks 4S and 4T to 1o in Fig. 1 as one calculation process, the transfer function of the control system is set to 0.
1, a block diagram of a transfer function when driving and controlling the T-reel 1 using a DC motor is shown in FIG. In FIG. 4, 16 is an arithmetic processing block composed of blocks 43.47 to 1o in FIG. 1; 16 is a block that converts input control voltage into motor generated torque;
17 is a block that converts torque into rotational angular velocity.

qrn is a voltage-current conversion constant, KT is a motor torque constant, I is the inertia of the T-reel drive motor, and S is another Lass converter.

The gain characteristic G1 of the control block 15 is obtained from the G1 formula: In the 00 formula, the value of the ratio R8/RT of the S and 7 reel radii is equal to the value of the ratio Ns/N'r of the outputs of the counters 68 and 6T. . Therefore, in equation (2), the rotation period T to be controlled by the T reel 10
T is determined by the tape transport speed V and the radius RT of the T reel 1.

Therefore, when the tape speed V to be controlled is constant, the T reel diameter and the gain characteristic G1 of the calculation processing 16 are (6), (1
The characteristics of formula 3 are as shown in Figure 6.

In FIG. 5, it can be seen that if the gain characteristic Gc of the gain adjuster 12 is constant, G and /T are factors that cause the loop gain to vary in the tape speed control system shown in FIG.

The inertia J of the T-reel 1 drive motor changes with the change in the tape winding diameter of the T-reel, but the amount of change is generally very small, and compared to the change in the gain characteristic G1 described above, it is not practical. This can be ignored, and here there is no inertia change in the T-reel drive motor, and I is assumed to be approximately constant. Therefore, it can be seen that the factor that changes the loop gain of the tape speed control system is G1.

As described above, when the gain characteristics of the control system change, it is not only difficult to configure an optimal control system, but also it may not be possible to configure a stable control system.

Therefore, in the present invention, the gain adjuster is operated so that the above-mentioned loose gain becomes approximately constant, so that a stable control system can be constructed.

Below, the arithmetic unit 11. The operation of the gain adjuster 12 will be mainly explained.

When the diameter of the T reel 1 changes and the loop gain characteristic of the Q1 speed control system changes, in order to keep this loop gain characteristic almost constant, the reciprocal of the gain characteristic shown in Fig. 6 is required. It is sufficient to perform gain correction with . That is, the first
The gain adjuster 12 in the figure performs gain correction corresponding to 1/G11. Assuming that the gain of the gain adjuster 12 is Gc, substitute equation (6) and substitute equation (4). In equation G4, if the tape speed V is constant, N 3 + N7 is also approximately constant as mentioned above. . Also, K
D and TC are constants uniquely determined when designing the device. Therefore, the gain adjuster 12 can perform the above-described gain correction if the value NT related to the T-reel diameter is known. That is, the arithmetic unit 11 receives the output values N of the six counters and performs the step a→expression 1). Then, the output result of the arithmetic unit 11 is input to the gain adjuster 12 to set the gain characteristics of the gain adjuster.

Therefore, as described above, in the tape drive device of the present invention, a stable tape transport control system can be constructed by providing means for correcting the gain in response to changes in the T-reel diameter.

Furthermore, microcomputers perform various calculations and store information.

It is well known that input/output control, timer operations, etc. can be performed, and in this embodiment, it is easy to realize this by replacing the blocks 6 to 9 and 11 of FIG. 1 with a microcomputer.

Further, in this embodiment, the gain correction calculation is performed according to the T-reel diameter, but the correction value related to the T-reel diameter is provided in advance as ROM data, and this ROM data is stored every time the T-reel diameter changes. There is no problem with the reading configuration.

Furthermore, in this embodiment, the gain correction calculation 'kT! Either the correction value is calculated based on information related to the rotation period of the J-reel, or the correlation between the S and 7 reels (for example, equation (8)) is used to determine the correction value related to the rotation period of the S reel diameter. It is easy to imagine what would be possible even with a configuration in which the correction value is determined based on information.

Effects of the Invention As described above, in a tape drive device that controls the tape speed to be approximately constant by controlling the sum of the rotation periods of the S and seven reels to be constant, conventionally, the tape winding diameter of the reel has been However, according to the present invention, the tape speed control system is equipped with a gain correction means that stabilizes the system, so that the tape speed control system can be stabilized. The roof gain of the system is almost constant, making the control system stable, and is extremely useful in realizing a high-performance tape drive.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a tape drive device according to an embodiment of the present invention, FIG. 2 is a waveform diagram for explaining the operation of the counter for detecting the rotation period of both reels in FIG. 1, and FIG.
The figure is the D/A converter 100 input/output characteristic diagram in Figure 1,
FIG. 4 is a schematic diagram showing the transfer function in the embodiment shown in FIG. 1, and FIG. 6 is a gain characteristic diagram of the control system that changes depending on the tape winding diameter. 4s...Supply reel rotation detector, 4T...
...Take-up reel rotation detector, 10...D/A
Converter, 12...Gain adjuster, 14...
...Take-up reel drive circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 21!1 Figure 3

Claims (1)

[Claims] Supply reel rotation period T_S, take-up reel rotation period T_T
and a reference value set corresponding to the tape speed to be controlled based on the respective information detected by the detection means and the sum of the rotation periods of the two reels. a first arithmetic processing means for calculating the difference between T_S+T_T; a take-up reel driving means;
gain variable means for outputting a control signal for controlling the take-up reel driving means by using the difference between the reference value calculated by the calculation processing means and T_S+T_T as an input signal; The open loop gain Gμ of the first arithmetic processing means is determined based on information related to the rotation period.
and second arithmetic processing means for calculating the reciprocal 1/G_μ of 1/G_μ to control the gain of the variable gain means, and controlling the tape speed to be substantially constant.