JPS59149259A - Automatic control of starting tension of web on web rewinding apparatus - Google Patents

Abstract

PURPOSE:To prevent rupture of a web by automatically starting at an optimum timing, the feedback control for a brake apparatus for adjusting the tension of a web in accordance with the set tension of the web. CONSTITUTION:The tension T1 at the present time which is detected by the first and the second web-tension detectors 5A and 5B and the set value T2 of a setting device 5C are compared in the first comparator 11, and a brake apparatus 4 for a web taking-up body is feedback-controlled so that the deviation is reduced to zero. In said feedback control, open-loop control is performed, setting a switch 12 as an initial-brake setting signal side, until the detected tension T1 reaches a control-start instruction tension TS supplied from a tension level setting apparatus for start 13, and when the tension TS is reached, the switch 12 is switched to start feedback-control. Thus, the rupture of the web due to the excessively early or slow start of feedback control is prevented, and the working performance can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for supporting the web when unwinding the web from a web wound into a large-diameter roll and controlling the web tension appropriately during web unwinding. The present invention relates to a method for automatically controlling web tension at startup in a web rewinding device that has a controlling function.

As shown in FIG. 1, the web rewinding device
The tension of the web rewound from the front and back is supported by a pair of front and rear fixed rollers A, B and the fixed roller 6, a detection roller 7 placed at an intermediate position between them to form a triangle, and both ends of the detection roller 7. The web tension is detected by a web tension detection device consisting of a pair of first web tension detector 5A and second web tension detector SB, and the detected web tension T1 and the web tension are
A tension controller '5r compares the web tension set in advance according to various conditions such as the material of The braking force of the brake acid gIII attached to the unwinding roll 3 is feedback-controlled (see FIGS. 2 and 3).

By the way, in such a web rewinding device, the start signal of the entire device including the web rewinding device (the start signal of the rewinding drive motor) is usually used as the start signal of the automatic web tension control system. There is. Therefore, if the timing to start feedback control of the brake force is not appropriate, various problems will occur as described below. That is, the control block diagram in FIG. 2 is one of the automatic web tension control systems used in conventional web rewinding devices, and switch lj is switched at the same time as the start signal of the rewinding drive motor to feedback the brake force! 111 to ffL#, but in this case, the start signal of the rewind drive motor (i.e., feedback control # start) is changed from the normal use of the variable speed motor as the rewind drive motor. There is a slight time difference between the signal input time and the actual starting time of the web rewinding device, so that when feedback control is started, there is still little tension on the web, and the As a result, the maximum braking force is applied to the rewind roll by feedback control, resulting in problems such as web breakage.

Also, a method of manually switching the switch /j in the second r1gJ has been adopted, but as in the conventional example described above, the web Although it is possible to prevent problems such as breakage from occurring, the operator must find an appropriate time during the work (in other words, when the conditions for starting feedback control are met) and switch/! ; must be switched to start feedback control, so it is completely self-a wJMl 11! : Not only is the operation complicated, but the start time of feedback control is determined by the operator's intuition, so there is a large variation in web tension at the beginning of web rewinding. For example, if the feedback control ayFJ start time is too early, In this case, since the web tension is still low, there is a large difference from the set tension, and the braking force increases rapidly, causing excessive tension to act on the web and causing the web to break. Even if the web does not break, as shown in Figure 3 As a result, tension overshoots and undershoots occur repeatedly, causing problems in the web. Conversely, even if the feedback control start time rule is delayed, the difference between the brake torque output at that point and the initial brake torque (h) is large, resulting in repeated overshoots and undershoots of the web tension, causing problems in the web. This can lead to web breakage in extreme cases.

In view of the above-mentioned eight problems of the web tension control system at startup in the conventional web rewinding device, the present invention provides feedback control of the brake device for adjusting the web tension according to the set tension of the web. By automatically starting rewinding at the optimal timing, the web tension at the first cut of unwinding can be maintained at the optimal value to prevent problems such as web breakage, and by promoting automation, the web tension can be maintained at the optimal value. The web tension detection device detects the unwinding tension of the web and adjusts the web unwinding tension by applying a braking force to the web winding body. and a tension controller that controls the braking force of the brake device in accordance with web tension,
A brake device is used to compare the detected web tension detected by the web tension detection device with a set web tension preset according to various conditions such as web material using a tension controller, and make the detected web tension converge to the set web tension. In the web rewinding device configured to perform feedback control on the braking force of 7, when web rewinding is started, activation of the feedback control of the brake device Δ by the tension controller is suspended and rewinding of the web is started using only an appropriate initial braking force. On the other hand, after starting web rewinding, 7 yen
/j The feedback control of the brake device by the tension controller is started when the detected web tension reaches the web tension for determining the start timing of the feedback control, which is set to a value smaller than the set web tension by a predetermined value. It is characterized by this.

Hereinafter, a method for automatically controlling the web tension at startup in the web rewinding device of the present invention will be explained with reference to FIG. 1, FIG. 5, and FIG. 5. FIG. A control block diagram of the automatic control system is shown. In this control system, the feed pack control is not activated at the same time as the start of the web rewinding device, and after the start of the web rewinding device, the detected web tension T1 becomes the set web tension T:
When the web tension for determining the start timing of feedback control (hereinafter referred to as control start command web tension) T, which is set to a value smaller than L by a predetermined value, is reached, the control is started automatically (1! II, control 1) to form a closed loop. As shown in the figure, the first and second web tension detectors! ; A + j
The current web tension T detected by n (detected web tension) is compared with a preset set web tension by the first comparison circuit, and the detected web tension T is converged to the set web tension. In the basic control circuit that feedback-controls the braking force applied to the web wound body 2 in order to force the winding, there is a closed-loop forming switch /2 that acts to switch on or off the closed loop of the feedback control;
A control start command web tension level setting device fa/ which outputs a signal corresponding to a control start command web tension set to a predetermined percentage value (IlO~10% in the illustrated embodiment) of the set web tension. 3 and a second comparison circuit/l are attached, and after starting the web rewinding device, the detected web tension T
I and the control start command web tension Tβ output from the start tension level setting device/3 are compared, and when the detected web tension T1 reaches the control start command web tension car, the second comparison time FM5/lI is determined. The output signal closes the closed-loop control switch /2 to establish a closed control loop and start feedback control of the brake device t. Note that this control closed loop is released by a stop signal of the web rewinding ffi motor. In addition, the control start command web tension T,
The level can be changed to the desired level using the setting device ffa/3. Furthermore, in this embodiment, the level of the control start command web tensioner is set as a ratio (%) to the set web tension T as described above, but in other embodiments of the present invention, this is set as a ratio (%) to the set web tension T. It can also be set by the difference (TI Tl) between - and the detected web tension T.

Next, the changes in web tension, braking force, and web rewinding speed in this control system will be explained with reference to FIG. 3. Preset initial braking force Fo
are continuously cut into corners. In this state, the web rewinding device is started.

After web rewinding has started, the tension starts to rise due to the initial braking force Fe and the braking force due to the inertia of the unwinding low and 3 parts. When the control start command web tension value (-) is reached, feedback control is started. let If the control brake torque output due to the difference in tension (T knee Tβ) at this time is equal to the initial brake torque (p, l), there will be no fluctuation in output at that point, and therefore the web will also be ITrll.
The fifth one is guided by the feedback fJI control loop without receiving
As shown in the figure, an ideal tension control system can be activated.

Next, to explain the present invention in detail, the method for automatically controlling web tension at startup in a web rewinding device of the present invention performs feedback control of a brake device that adjusts web tension until the detected web tension is lower than the set web tension. Since it is possible to set the start command to start at the optimum timing in a self-excited manner only when the so-called start command web tension is reached, which is a smaller value, it is possible to prevent web breakage or web breakage caused by premature or delayed start timing of feedback control. This has the effect of preventing the hunting phenomenon of web tension from occurring and improving work characteristics.

In addition, since feedback control of the brake device can be automatically started at the optimal timing according to the web tension, it is easier to start feedback control manually than when the operator directly starts feedback control. Automation is promoted, which also has the effect of improving the workability of web rewinding work.

Furthermore, the method for automatically adjusting the web tension at startup in the web rewinding device of the present invention adjusts the value of the control star 1 command web tension for starting the feedback control of the brake device according to the material of the web, etc. In order to be able to automatically set the web tension to a predetermined value according to the value of the set web tension that is changed and set as appropriate, the control start command web tension is artificially reset every time the set web tension is changed. This has the effect of simplifying the operation and improving workability.

[Brief explanation of the drawing]

Figure 1 is a system diagram of a web rewinding device, Figure 2 is a control block diagram of a conventional automatic web tension control system at start-up, and Figure 3 is a brake diagram when braking force is controlled by a conventional automatic web tension control system. FIG. 4 is a control block diagram of the web tension automatic control system at startup according to the embodiment of the present invention, and FIG. 5 is a diagram of changes in force and web tension.
It is a change state diagram of web tension and web rewinding speed when braking force is controlled based on the control block diagram shown in the figure. /...Web 2...Web winding body l...Brake device l/...1st comparison circuit/2...For closed loop configuration switch Norihisa Sakabe 1, !
~,;2+,1,

Claims (1)

[Claims] 1. A web tension detection device (9) that detects the unwinding tension of the web (1) and a braking force applied to the web winding body (, 2) to reduce the unwinding tension of the web (1).
a! Brake equipment that works perfectly! ! (4) and a tension controller <r> that controls the braking force of the brake device (4') according to the web tension, and the detected web tension (T1) detected by the web tension detection device (?) and the set web tension (-) set in advance according to various conditions such as web material, and the tension controller < r
> in order to converge the detected web tension (T,) to the set web tension h (''z).
4') In the web rewinding device in which the brake force is feedback-controlled, at the start of web rewinding, the tension controller (lr) controls the brake system Ml.
Activation of the feedback control (L) is suspended and the web (1) is started to rewind using only an appropriate initial braking force (FO), while after the start of web rewinding, the detected web tension (T+) is When the web tension (T, 8) for determining the start of the feedback control, which is set to a value smaller than the web tension (T, ) by a predetermined value, is reached, the braking device is controlled by the tension controller (to). ＞ to start feedback control.