JPH0445426B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a device for transporting a flexible medium such as a tape or a web from reel to reel, and particularly relates to a device for transporting a flexible medium such as a tape or a web from reel to reel. The present invention relates to a tape transport method and apparatus suitable for.

[Prior art] and [Problems to be solved by the invention] Conventional devices are disclosed in, for example, Japanese Patent Laid-Open No. 52-62004,
There is one described in Japanese Patent Application Laid-Open No. 53-144307. In these conventional devices, the motor current required to start the tape is calculated and set individually for each motor. However, no consideration was given to mutual interference between the two motor inputs. This has resulted in the disadvantage that tape tension fluctuations occur, making it impossible to transport the tape with high accuracy.

Further, the conventional device does not take into account mismatching of the motor current setting value caused by variations in mechanical parts. Therefore, there is a drawback that tape tension fluctuation occurs and highly accurate tape transport is not possible.

The object of the present invention is to provide tape from reel to reel;
In a device that transfers flexible media such as webs, it suppresses mutual interference between the motor inputs that drive two reels separately to suppress fluctuations in tape tension, and also suppresses tension fluctuations due to variations in parts etc. An object of the present invention is to provide a tape feeding control method and device that can transfer tape with high precision.

[Means to solve the problem]

In devices that transfer flexible media such as tape or web from reel to reel, once tape tension fluctuations occur, there is nothing to absorb the fluctuations, so the mechanism is difficult to attenuate. A control means that does not cause tension fluctuations is required. Here, it has become theoretically clear that the tape tension fluctuation occurs due to a motion error between the two reels inside the device. From this result, it was experimentally confirmed that by controlling the input of each motor that drives the two reels under certain conditions, the tape could be transferred with high precision without causing fluctuations in tape tension. However, if there is a variation error in mechanical parts, mismatching with the above-mentioned design value occurs, and tape tension fluctuation occurs. The key point here is how to detect variations in mechanical parts. Fortunately, the magnitude of mismatching from non-interfering input conditions and
It was found that there is a proportional relationship with the tape tension fluctuation that occurs. Therefore, it is possible to automatically compensate for variations in mechanical parts by measuring tape tension fluctuations, estimating errors from non-interfering input conditions, and correcting or resetting set values. can.

That is, the present invention provides a tape feed control method when two reels are driven by separate motors and the tape is transferred from one reel to the other reel, in which the reel radius r ₁ applied to the two motors is , r ₂ , inertia of rotating parts J ₁ , J ₂ ,
When the proportionality coefficient is R, the drive current of the two motors i ₁ required to eliminate the tape speed error is
i ₂ is distributed so that the ratio thereof satisfies the formula i ₁ /i ₂ = (J ₁ r ₂ /J ₂ r ₁ )R, and at the same time, the fluctuation in tape tension is detected and the amount of fluctuation is removed. The present invention is characterized in that the proportional coefficient of the above equation is corrected as follows, and the distribution of drive currents of the two motors is set to be increased or decreased so as to satisfy the corrected equation.

Further, in a tape feed control device that drives two reels by separate motors and transfers the tape from one reel to the other reel,
The reel radii r ₁ and r ₂ applied to the two motors are
reel diameter detection means for detecting the respective reel diameters, inertia calculation means for respectively calculating the inertias J ₁ and J ₂ of the rotating parts applied to the two motors based on the detected reel radii, and the reel radius and inertia detected or determined. and the speed error of the tape, and the driving currents i ₁ and i ₂ of the two motors required to remove the speed error are:
Drive current control means that sets the distribution so that the ratio thereof satisfies the formula i ₁ /i ₂ = (J ₁ r ₂ /J ₂ r ₁ )R (where R is a proportional coefficient), and the tape tension and an adjusting means for inputting the detected tension, detecting the amount of tension variation, and correcting the proportionality coefficient of the equation to remove the amount of variation, and the drive current control means The present invention is characterized in that the distribution of drive currents of the two motors is complementarily increased or decreased so as to satisfy the equation after the proportionality coefficient is corrected.

〔Example〕

Examples of the present invention will be described below.

FIG. 1 shows an embodiment of the invention.

In the figure, the tape transport device runs a magnetic tape at a predetermined speed, records information on the tape, and reproduces information from the tape. 5
1 is a magnetic tape, and 3 and 4 are reels on which a tape 5 is wound.These reels 3 and 4 are driven by motors 1 and 2, respectively. By driving the motors 1 and 2, the magnetic tape 5 is transferred from one reel 4 to the other reel 3 via a tension sensor 9, a magnetic head 6, and a speed tachometer roller 8.

In the reel-to-reel method, the tape is transferred by controlling the rotation of reels 3 and 4. In order to determine the drive current of motors 1 and 2, the tape radius on the reel (hereinafter referred to as reel), which is an unknown variable, is radius). There are various methods for detecting the reel radius, but one example is shown below. 11 and 12 are tachometers, and reels 3,
Detect the rotation amount of 4. On the other hand, 10 is a minute tachometer, which detects minute rotations of the speed tachometer roller 8. The length of the tape wound by the reel 3 is equal to the length of the tape passed through the speed tachometer roller 8. Therefore, the radius of the reel 3 can be determined by comparing the rotation amounts of both. reel 4
The same applies to The controller 16 calculates the radii of the reels 3 and 4 in response to the signals from the tachometers 10, 11 and 12 using the radius calculation algorithm described above. In the case of this reel radius detection method, the reel radius can be detected every time a signal is generated by the tachometers 11 and 12.

The controller 16 calculates the drive currents of the motors 1 and 2 using the reel radius, inertia, and proportionality coefficient in accordance with a control algorithm described later, and controls the motion of the motors 1 and 2 via the power amplifiers 14 and 15. do.

On the other hand, the tension sensor 9 detects the tension of the tape 5, and an example of its configuration is shown in FIG. The roller 7 on which the tape 5 is applied is rotatably supported by a roller support 32, and the roller support 32 is fixed to a fixed block 28 via a leaf spring 29. Further, a differential transformer 30 is installed under the roller support 32 so that its position can be adjusted, detects the displacement of the roller support 32, and converts a voltage value representing tension using the sensor circuit 13.

Further, the tape speed can be determined by counting the period of the pulse signal of the fine tachometer 10. Here, the period has a reciprocal relationship with the speed.

Next, a control algorithm for setting the drive current of each motor using the reel radius, inertia, and proportionality coefficient will be described. Figure 3 shows the controller 16
FIG. 3 is a diagram showing the parts related to the setting of the drive current of each motor in the diagram. Tapes are typically transported or data exchanged under constant tension. Reference numerals 21 and 22 in the figure are current generators that apply a constant current to the motor to generate a predetermined tape tension. In addition,
The current for generating tape tension is set by the following formula (1).

i _T = 1/K _T r・f _T …(1) where, i _T : Tension current K _T : Motor torque constant r : Reel radius f _T : Tape tension In addition, the magnetic head 6 generated when transporting the tape , it is necessary to generate a correction torque in the motor for the running frictional resistance between the tape guide (not shown), etc. and the tape, and therefore a frictional current is added in addition to the tension current from the current generators 21 and 22. There is. Note that the frictional current is set by the following formula (2).

i _f = i/K _T rf _N・(-1) = ...(2) where, i _f : Frictional current f _N : Frictional force α : 1 or 0 depending on the running direction Next, the motor for controlling tape running The drive current is set as follows. 17 is a target speed generator that provides a target speed, and the target speed is compared with the actual tape speed detected by the fine tachometer 10. Here, 18 is a converter that converts the signal from the fine tachometer 10 into a voltage signal representing speed. The detected speed error is sent to the amplifier 19, where the error signal is amplified and filtered. Note that the amplification factor and filter constant are set in advance in consideration of the quick response and stability of the servo system.
The error signal is then distributed to the two motor drive currents in a decoupling controller 20. In other words, the reel
In a multi-input, multi-output system having two actuators inside the system, such as a two-reel type tape running mechanism, mutual interference occurs inside the system. In this system, tape tension fluctuations occur as a result of mutual interference. Therefore, the role of the non-interference controller 20 is to distribute and set the current command values of the two motors,
Especially when two motors interfere with each other,
The purpose of this invention is to change the distribution of the motor current based on the detected value of tape tension fluctuation between the two reels, reduce mutual interference between the motors, and stabilize tape running.

In addition, in the deinterference controller 20, the following formulas (3) to (5) are used.
The motor drive current is set from the speed error, reel radius, inertia, and proportionality coefficient as shown below.

i ₁ = J ₁ /r ₁・ΔV・R ₁₁ …(3) i ₂ =J ₂ /r ₂・ΔV・R ₁₂ …(4) i ₁ =J ₁ r ₂ /J ₂ r ₁ R ₂ i ₂ ...(5) Here, i ₁ : Drive current of motor 1 i ₂ : Drive current of motor 2 J ₁ : Rotating part inertia of motor 1 J ₂ : Rotating part inertia of motor 2 r ₁ : Radius of reel 3 r ₂ : Radius ΔV of reel 4 : Speed error R ₁₁ , R ₁₂ : Proportionality coefficient R ₁₁ = a/K _T R ₁₂ = b/K _T R ₂ : Proportional coefficient R ₂ = R ₁₁ /R ₁₂ = a/b. The proportional coefficients R ₁₁ and R ₁₂ are the reel radius r ₁ ,
r ₂ , motor torque constant K _T which is a constant other than inertia, and other coefficients assumed to represent errors included in the reel/motor system.
If there is no error in the motor system, a=b=1.

Also, from equation (5), the two motor drive currents i ₁ and i ₂
is related only to the motor inertia and reel radius, and the proportional coefficient R ₂ is the ratio of the error between the proportional coefficients R ₁₁ and R ₁₂ , but it is also a proportional coefficient that aggregates the variation errors of mechanical parts or electronic circuit parts, etc. It can be treated as R. Note that in an ideal case where there is no error in each reel/motor system and there is no variation error in component parts, R ₂ =1.

The motor rotating part inertias J ₁ and J ₂ are values determined by the radii r ₁ and r ₂ as shown in equation (6) below, and are set by calculation using the reel radius inside the non-interference controller 20. Alternatively, a method may be used in which a result calculated in advance using the reel radius as an argument is stored in a storage element. As described above, the control algorithm for setting the drive current of each motor using the reel radius has been explained, but the feature of the present invention is that the non-interference controller 20 allows the error signal to be
The point is to set the two motor currents so that they do not cause interference.

J _i = J _p + π/2α (r ⁴ _i − r ⁴ _p ) …(6) where, J _i : Rotating part inertia i=1,2 J _p : Initial inertia (without tape) r _i : Reel radius i = 1, 2 r _p : Initial reel radius (no tape) α: Constant determined by the tape Next, in order to automatically compensate for variations in mechanical parts or electronic circuit parts,
Explain adaptive algorithms. proportionality coefficient
R ₂ is initially set to R ₂ =1 assuming that there is no mutual interference between the two motors. However, in actual devices, there are variations in mechanical parts, electronic circuit parts, etc., so when the tape is run, tension fluctuations in the tape occur due to mutual interference between the two motors. Therefore, as explained below, the variation in tape tension is determined and the proportional coefficient is calculated using the above proportional coefficient.
Mutual interference between the two motors is removed by correcting _R2 . If there is the above-mentioned variation error, the set value of the non-interference controller 20 in the controller 16 will be mismatched with respect to the controlled object. Figure 4 shows
The tension sensor 9 detects the tape tension fluctuation that occurs in this case.
This is an example of a sketch diagram measured by the method. Figure 4 a to c are mismatching of non-interference conditions and the following formula
Corresponds to (7) to (9). For example, in a of FIG. 4, the tape tension fluctuation Δf occurs in the positive direction because the movement of the reel 3 is faster than that of the reel 4. On the contrary, c is
Since the movement of the reel 3 is slower than that of the reel 4, the tape tension fluctuation Δf occurs in the negative direction. on the other hand,
In b, the motion of reel 3 is almost equal to that of reel 4, and the tape tension fluctuation Δf is close to zero.

Corresponding to a i ₁ /i ₂ > J ₁ r ₂ /J ₂ r ₁ R ₂ ...(7) Corresponding to b i ₁ /i ₂ = J ₁ r ₂ /J ₂ r ₁ R ₂ ...(8) to c Correspondence i ₁ /i ₂ <J ₁ r ₂ /J ₂ r ₁ R ₂ ...(9) Here, in order to make the tape tension fluctuation Δf zero as shown in b in Fig. 4, for example, in the case of a It turns out that it is sufficient to make the movement of reel 3 relatively slower than that of reel 4. This corresponds to modifying the proportionality coefficient R ₂ in equation (5) to be smaller than the current value. Conversely, in case c, the movement of reel 3 should be made relatively faster than that of reel 4. This corresponds to modifying the proportionality coefficient R ₂ in equation (5) to be larger than the current value.

Further, the above-mentioned tape tension fluctuation Δf is small when the tape is running normally, and becomes large when the tape speed is accelerated or decelerated. This is mainly because the motor current increases during acceleration or deceleration, and the influence of mutual interference between the two motors increases.

In addition, the proportionality coefficient R ₂ may be corrected each time based on the detected tape tension variation Δf, but in practice, it is If the device conditions related to tape feeding control of circuit components and the like are constant, the tension fluctuation Δf during acceleration or deceleration will be approximately constant. Therefore, it is sufficient to appropriately detect the tape tension fluctuation Δf during acceleration or deceleration, and correct the proportionality coefficient R ₂ to remove the fluctuation. In addition,
Fixed proportionality factor R ₂ also at steady speed of tape
However, the tendency of tension fluctuations due to component variation errors is the same as during acceleration or deceleration, and the motor current at steady speed is sufficiently small compared to acceleration and deceleration. Therefore, the effect of modifying the proportionality coefficient R ₂ is small and does not pose a problem.

In FIG. 3, the tape tension is measured by the tension sensor 9
and is measured as a voltage value by the sensor circuit 13. The regulator 23 receives the output of the sensor circuit 13, detects the tape tension variation Δf, and uses this to modify the proportionality coefficient R ₂ according to the adaptive algorithm for automatic adjustment described above. In addition, when making appropriate corrections according to acceleration/deceleration, based on the change in the target speed output from the target speed generator 17,
The temporal timing of accelerating or decelerating the tape is detected, and the tape tension fluctuation Δf that occurs when the tape is accelerated or decelerated in accordance with this is detected. In this case, in order to improve detection accuracy, the regulator 23 is set with a detection algorithm that takes in the output of the sensor circuit 13 several times and averages it.
Next, the adjuster 23 uses the detected tape tension fluctuation Δf to correct the proportional coefficient R ₂ of the deinterference controller 20 in accordance with the above-described adaptive algorithm for automatic adjustment. By repeating the above corrections, variations in mechanical parts and electronic circuit parts in an actual device are automatically corrected.

Automatic correction of this variation error can be performed at any time when the tape tension fluctuation occurs.
In particular, if you perform this automatic correction several times when loading the tape, before each component has stabilized thermally, such as immediately after the power is turned on, and when tape tension fluctuations are likely to occur, it is possible to reduce the tape transport device for a short time. When exchanging data on the tape, fluctuations in tape tension are small, increasing the operating time that allows data exchange. In addition, if preset correction is performed at the time of first power-on for variations inherent to the device, such as mechanical parts, the tape tension fluctuations will become smaller and the degree of correction required will be reduced, resulting in an operation that allows data exchange. Time increases.

Here, the tape tension fluctuation Δf detected by the regulator 23 is the value detected during the time when the tape is accelerated or decelerated, and the value detected during the time after the tape reaches a steady speed, as shown by the arrow in FIG. Take the difference from the value,
It is preferable to vary the tape tension. Furthermore, when modifying the proportionality coefficient R ₂ in the deinterference controller 20,
Rather than changing only one motor current in response to the amount of correction, it is desirable to distribute the increase/decrease evenly and complementary to both motors. This allows tape tension fluctuations to be quickly removed or stabilized.

〔Effect of the invention〕

As explained above, according to the present invention, the reel radius is detected, the inertia of the rotating part is determined, and the drive current of the two motors is distributed and set based on these. Mutual interference between two motor inputs, which is a problem in this method, can be effectively prevented. In other words, since the drive current required to eliminate speed errors can be distributed more accurately, the error in tape feed amount that occurs when two motors are driven can be reduced, and the tape tension fluctuation that occurs in proportion to the tape feed amount can be reduced. This has the effect of making it smaller. Therefore, the servo control system, which tends to cause tape tension fluctuations when there is an error in the motor drive current, can transport the tape with high precision without causing tape tension fluctuations.

In particular, when distributing the drive current required to eliminate speed errors, changes in the reel radius and inertia, which are related to the characteristics of current and speed, are reflected, so responsiveness is improved compared to simple speed feedback control. It has the effect of being superior.

In addition, if there is a detection error in the above two parameters due to variations in mechanical parts or electronic circuit parts, or if the relationship between the motor current and speed characteristics changes due to factors other than the above two parameters. In this case, by detecting the tape tension variation caused by driving the two motors and correcting the changed relationship between the motor current and speed characteristics based on the tape tension variation value, the tape produced by driving the two motors is detected. This has the effect of reducing tension fluctuations. In addition, correction of variation errors can reduce the extra power supply capacity for feed back correction, resulting in labor savings.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is an external view of the tension sensor, and FIG. 3 is a diagram showing the parts related to setting the drive current of each motor in the controller 16.
FIG. 4 is a diagram showing measurements of tape tension fluctuations. 1, 2...Motor, 3, 4...Reel, 5...
tape, 6...magnetic head, 9...tension sensor,
10... Fine tachometer, 16... Controller, 20
...Decoupling controller, 23...Adjuster.

Claims (1)

[Claims] 1. A tape feeding control method when two reels are driven by separate motors and the tape is transferred from one reel to the other reel, wherein the reel radius applied to the two motors is _r1 ,
r ₂ , inertia of the rotating part is J ₁ , J ₂ , proportional coefficient is R
Then, the drive currents i ₁ and i ₂ of the two motors required to eliminate the tape speed error are expressed as the ratio of them: i ₁ /i ₂ = (J ₁ r ₂ /J ₂ r ₁ )R In addition to setting the distribution so as to satisfy the above equation, detect the tension fluctuation of the tape, correct the proportional coefficient of the above equation to remove the amount of variation, and drive the two motors so as to satisfy the above corrected equation. A tape feeding control method characterized by setting an increase/decrease in current distribution. 2. In a tape feed control device that drives two reels by separate motors and transfers the tape from one reel to the other reel, the reel radii r ₁ and r ₂ applied to the two motors are detected, respectively. reel diameter detection means; inertia calculation means for calculating the inertias J ₁ and J ₂ of the rotating parts applied to the two motors based on the detected reel radius; At the same time, the speed error of the tape is input, and the drive currents i ₁ and i ₂ of the two motors required to remove the speed error are calculated using the formula i ₁ /i ₂ = (J ₁ r ₂ /J ₂ r ₁ ) R (where R is a proportionality coefficient.) Drive current control means for setting the distribution to satisfy adjustment means for detecting the amount of tension variation and correcting the proportionality coefficient of the equation to remove the variation; A tape feeding control device characterized in that the distribution of driving currents of two motors is increased or decreased in a complementary manner.