JPH09169455A - Tension control method for driving device for rewind roll - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide proper compensation without requiring complicated computation by, in the case where after removing slack before the beginning of operation, the set value of a tension setter is lower than the set value of a static friction tension setter, adding a difference between the above set values to a tension set value for a fixed time after the beginning of operation. SOLUTION: The set value of a tension setter 10 and the set value of a static friction tension setter 21 are inputted into a static friction compensator 22. In the case where the set value of the tension setter 10 is lower than the set value of the static friction tension setter 21, a difference between the above set values, namely a value obtained by subtracting the tension set value from the static friction tension set value, after removing slack and then starting the operation, is added to the tension set value for a fixed time. This set value acts so as to rotate a rewind roll in the same direction as a carrying direction. Since actual static friction force decreases rapidly after the beginning of operation, compensating tension added to the set tension in this way may decrease with the elapse of time, or keep a fixed value for a fixed time according to circumstances. Thus the device dispenses with complicated computation.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tension control method for a rewinding roll driving device in an unwinder for rewinding a web of paper, film or the like. 2. Description of the Related Art Conventionally, in such a tension control method, the rewinding roll 2 and the transport roll 11 are prior to operation.
In order to remove the slack between the two, for example, JP-A-3-2665.
A low tension, that is, a stall tension as shown in No. 1 was applied, and after removing the slack, the line was controlled at a predetermined operating speed and operating tension. In this method, when the stall tension is applied, the unwinder 2 rotates in the direction opposite to the conveying direction to remove the slack and realizes the tension. When the unwinder 2 starts to rotate in the conveying direction in this state, static friction is applied to the product 1 in addition to the set tension, and if the resultant force exceeds the breaking tension of the product 1, the product 1 breaks. However, rewinding from the unwinder 2 becomes impossible. Moreover, even if it does not break, excessive elongation may occur, resulting in a defective product. Therefore, as in JP-A-5-162909,
It has been proposed to compensate the static friction tension in order to prevent tension fluctuations at start-up. FIG. 2 shows a control principle of a tension control device of a rewinding roll driving device in a conventional unwinder based on this proposal. 1 is a web, 2 is a rewinding roll, 3 is a coupling, 4 is a rewinding roll. Electric motor for roll, 5 drive device for rewinding roll, 6 tension controller, 7 tension command generator, 8 tension detector for detecting web tension, 9 tension control "ON"
Contact point closed by 10, a tension setting device, 11 a transport roller that transports the web while rotating by sandwiching the web 1 between the rolls, 12 a transport roll electric motor that drives the transport roll 11, 13 a speed detector, 14 Is a transport roll driving device, 15 is a speed controller, 16 is a line speed commander, 17
Is a line speed setting device, and 18 is a contact point that is closed during operation.
The transport roll 11 is controlled to the speed set by the line speed setting device, and the rewinding roll 1 is controlled to have the tension command value output by the tension command generator 7. Next, the operation will be described. The rewinding roll electric motor 4 is driven by the rewinding roll driving device 5, and power is transmitted to the rewinding roll 1 via the coupling 4. The rewinding roll electric motor 4 is tension controlled by a tension controller 6 according to a command from a tension command generator 7. The tension measured by the tension detector 8 is used as a feedback signal. The tension by the rewinding roll is opposite to the web 1 conveyance direction (rightward in the figure). Also, the electric motor 1 for the transport roll
2 is driven by the transport roll driving device 14, and is controlled by the speed controller 15 to the speed set by the line speed setting device 17 in accordance with the instruction of the line speed command device 16. The detection signal from the speed detector 13 of the transport roll is used as a speed feedback signal. Reference numeral 19 is a pulse generator for rewinding roll diameter measurement, and 20 is a static friction compensation calculator. The inertia compensation function and the mechanical loss compensation function are not shown. According to this, the pulse oscillator 1 that works with the rewinding machine
According to the roll diameter of the rewinding machine measured by 9, the static friction compensation calculator 20 calculates the loss due to static friction and outputs it to the tension command generator 7. However, in this method, since tension due to static friction according to the diamond diameter of the rewinding machine is compensated, complicated calculation is required and the CPU of the controller is occupied. Therefore, there is a drawback that other control calculations are hindered. In addition, since this compensation is performed for a long time after the start of operation, there is a drawback that the compensation becomes excessive and the tension control accuracy is lowered. Therefore, the present invention proposes a tension compensation method that realizes appropriate compensation without requiring complicated calculation. In order to solve the above problems, the present invention provides a transport roll driving device for driving a transport roll of a web, which is speed-controlled at a transport line speed set by a line speed setting device. And the rewinding roll driving device of the rewinder control device comprising a rewinding roll driving device for driving the rewinding roll of the wound web, a tension command value by a tension setting device and a tension command generator. In the tension control method of the rewinding roll driving device for controlling the tension by providing a tension controller for controlling the tension,
Equipped with a static friction tension setter and a static friction compensator, after completing the slack removal before the start of operation, if the set value of the tension setter is lower than the set value of the static friction tension setter, the operation start command of the line At the same time when the conveyance roll is started, the difference between the set value of the tension setter and the set value of the static friction tension setter is added to the tension set value for a certain period after the start of operation. According to the present invention, it is possible to realize appropriate static friction compensation without requiring complicated calculation. Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. The same parts as in FIG. 2 are given the same numbers. Explaining only the parts different from FIG. 2, 21 is a static friction tension setting device, 22
Is a static friction corrector. The set value of the tension setter 10 and the set value of the static friction tension setter 19 are input to the static friction corrector 20. When the set value of the tension setter 10 is lower than the set value of the static friction tension setter 19, the difference, that is, the value obtained by subtracting the tension set value from the static friction tension set value, is used after the start of operation after the slack removal is completed. , Add to tension setting for a certain period of time. This set value acts to rotate the unwinder 2 in the same direction as the transport direction. In this way, the compensation tension added to the set tension may be decreased over time or may be a fixed value for a certain period of time, because the actual static friction force rapidly decreases after the start of operation. As described above, according to the present invention, it is possible to prevent excessive tension in the initial stage of operation of the unwinder and to prevent product breakage and product defects by a simple method without requiring complicated calculation. It is possible to provide a product that is suppressed and has a high yield.

[Brief description of the drawings] FIG. 1 is a configuration diagram of an embodiment of the present invention. FIG. 2 is a block diagram of a conventional example [Explanation of symbols] 1 product 2 Rewind roll 3 coupling 4 Rewinding roll electric motor 5 Rewinding roll driving device 6 Tension controller 7 Tension command generator 8 Tension detector 9 Close contact point with tension 10 Tension setting device 11 transport rolls 12 Conveyor roll electric motor 13 Transport roll speed detector 14 Transport roll drive 15 Speed controller 16 line speed commander 17 Line speed setting device 18 Contact points that close with operation 19 Rewinding roll diameter pulse generator 20 Static friction compensation calculator 21 Static friction tension setting device 22 Static friction corrector

Claims (1)

Claim: What is claimed is: 1. A conveyor roll driving device for driving a conveyor roll of a web, the speed of which is controlled at a conveyor line speed set by a line speed setter, and a rewinding roll for driving a rewinding roll of a wound web. The rewinding roll drive device of the rewinder control device including a drive device is provided with a tension controller for applying a tension command value by a tension setting device and a tension command generator to control tension, and rewinding for controlling tension. The tension control method for the roll drive device is equipped with a static friction tension setter and a static friction compensator, and after the slack removal before the start of operation is completed, the set value of the tension setter is the set value of the static friction tension setter. If it is lower than the above, the difference between the set values of the static friction tension setter and the set value of the static tension tension setter is set at the same time when the start of the transport roll is started by the line start command Rewind tension control method of the roll drive device, characterized in adding to the rear fixed time tension setting value.