JPH0442307B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a steel strip tension control device for a loop car in a continuous steel strip processing line.

[Conventional technology]

Steel strip continuous processing line (pickling treatment, annealing treatment, etc.)
In order to continuously feed the steel strip to the processing section, welding is performed to add the trailing steel strip to the preceding steel strip on the upstream side of the processing section, and on the downstream side of the processing section, The steel strip is cut into a predetermined length.
When this welding or cutting work is performed, the running of the steel strip will temporarily stop at that part, so the entrance and exit sides of the processing section should be set so that the running of the steel strip in the processing section does not stop during this work. A loop car will be installed. Fig. 2 shows an example in which a loop car 2 is installed on the inlet side of the processing section 1, and the loop car 2 is moved by a loop car drive motor 3 at appropriate times and by an appropriate distance to change the loop length of the steel strip S. The strip is constantly passed through the processing section 1 at a constant speed.

When moving the loop car 2, the speed of the steel strip is different between the entrance side A and the exit side B of the loop car, and the speed difference also changes, so appropriate control of the movement timing, movement speed, movement distance, etc. of the loop car is necessary. This is necessary to maintain constant tension in the loop car. If the tension becomes too low, flapping (vibration) or meandering of the steel strip will occur.
On the other hand, if it becomes too high, it will have a negative effect on the equipment, and in extreme cases, accidents such as plate breakage (steel strip breakage) may occur. Moreover, the tension fluctuation of the loop car makes the tension of the steel strip in the processing section 1 unstable, and becomes a cause of preventing smooth processing of the steel strip.

As a tension control device to maintain the tension of the loop car constant, it calculates the speed command of the loop car according to the deviation of the steel strip speed feedback FB on the entrance and exit sides of the loop car, and calculates the difference between the command value and the loop car speed FB. A current command to be given to the loop car drive motor is calculated according to the deviation, and a value obtained by adding the current command value and a current command value for the tension of the loop car is used as a current reference value of the loop car drive motor to control the current of the motor. It is known what has been done.

[Problem that the invention seeks to solve]

In the above tension control device, the calculated speed command constantly changes while the steel strip speed on the input and output sides changes, and the actual loop car speed is determined by the output of the loop car drive motor by controlling the current. This is detected as a result of the loop car moving due to a change in the tension between the electric motor and the steel strip tension. Therefore, the speed of the loop car always lags behind the command value. , the tension cannot be kept constant all the time.

The present invention provides a tension control device that sensitively responds to changes in steel strip speed on the entrance and exit sides of a loop car and can maintain constant tension.

[Means and actions for solving problems]

The loop car tension control device for a continuous steel strip processing line of the present invention includes: a computing unit that calculates a moving speed command value of the loop car according to the difference between the steel strip speed on the inlet side and the steel strip speed on the outlet side of the loop car; a calculator that calculates a speed current command value for the loop car drive motor according to the difference between the speed command value and the loop car moving speed; and a calculator that adds the speed current command value and a tension current command value corresponding to a predetermined steel strip tension. , an adder that outputs the total value, and an operation that calculates the rate of change in the speed difference between the incoming steel strip speed command value and the outgoing steel strip speed command value, and calculates a current correction value according to the rate of change. adding the current correction value to the total value of the speed current command value and tension current command value of the loop car drive motor, and applying the total value to the automatic current control device of the motor as a current reference value of the loop car drive motor. It consists of an adder that outputs.

FIG. 1 is a block diagram showing the configuration of a tension control device according to the present invention. To explain with reference to the figure, first, the input side steel strip speed FB and the exit side steel strip speed FB of the loop car are input to the calculator 1, and a loop car moving speed command value is calculated according to the speed difference between the two. Ru.
The speed command value and the moving speed FB of the loop car are input to a computing unit 2, and the computing unit 2 computes a speed current command value for the loop car drive motor according to the difference between the two. In addition, in the computing unit 2, normally,
Mechanical loss is compensated by inputting a current value commensurate with the mechanical loss of the loop car.

Furthermore, the speed current command value output from the arithmetic unit 2 is input to the adder 1 along with the current command value corresponding to a predetermined tension of the steel strip, and the sum of both is output from the adder 1 to the adder 2. be done.

On the other hand, in parallel with this, the input side steel strip speed command value and the output side steel strip speed command value are input to the calculator 3.
By differentiating the speed difference with respect to time, the rate of change in the speed difference (dΔv/dt) is calculated, and the change in the speed difference is calculated based on the correlation between the predetermined rate of change and the current correction amount. A current correction value for the rate is calculated. Furthermore, even if there is a difference in the speed of the steel strip between the entrance and exit sides of the loop car, the current correction value calculated by the calculator 3 is zero when the speed difference remains unchanged (dΔv/dt=0). be.

The loop car current correction value output from the calculator 3 is input to the adder 2 together with the signal output from the adder 1 (the sum of the loop car speed current command value and the current command value for the tension of the steel strip). The adder 2 outputs the total value.

The present invention uses the signal output from the adder 2 as a current reference value for the loop car drive motor.
The movement of the loop car is controlled by inputting it to the automatic current control device of the electric motor.

In the present invention, as described above, when the speed difference between the steel strips on the entrance and exit sides of the loop car is changing, by adding a current correction value corresponding to the change to the loop car drive current reference, Since the delay in the actual loop car movement speed relative to the loop car speed command value is corrected, the steel strip will always maintain a constant tension even if the steel strip speed or speed difference between the input and exit sides of the loop car changes. maintained. Note that the current correction value is zero when the speed difference between the steel strips on the entrance and exit sides of the loop car is unchanged, so in that state, it functions the same as a conventional device that is not equipped with the calculator 3. The tension is controlled by.

〔Effect of the invention〕

The control device of the present invention sensitively responds to changes in the speed of the steel strip on the entry and exit sides of the loop car, and maintains the tension of the steel strip in the loop car constant at all times. It is possible to prevent problems (such as flapping and meandering of the steel strip due to a decrease in tension, adverse effects on machinery and equipment due to an increase in tension, and breakage of the steel strip), as well as improve the threading condition of the steel strip in the processing section of the line. This contributes to streamlining line operations and improving processing quality.

In addition, as another means of controlling the steel strip tension, by detecting the tension using a tension meter and controlling the torque of the electric motor of the bridle roll 4,
Devices that maintain a constant steel strip tension are known, but installation of a tension meter and the like requires a large amount of cost. The control device of the present invention is a simple device that adds a current correction value to the loop car drive current reference, and has low cost and great practical value.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is an explanatory diagram of the main parts of a continuous steel strip processing line. 1... Processing section, 2... Loop car, 3... Loop car drive motor, 4... Bridle roll.

Claims (1)

[Scope of Claims] 1. A computing unit that calculates a moving speed command value of a loop car according to the difference between an inlet steel strip speed and an outlet steel strip speed of a loop car in a continuous steel strip processing line; A calculator that calculates a speed current command value for the loop car drive motor according to the difference from the loop car moving speed, and a calculation unit that adds the speed current command value and a tension current command value corresponding to a predetermined steel strip tension, and calculates the total value. an adder that outputs; a calculator that calculates a rate of change in the speed difference between the incoming steel strip speed command value and the outgoing steel strip speed command value, and calculates a current correction value according to the rate of change; an adding machine that adds the current correction value to the total value of the speed current command value and tension current command value of the loop car drive motor, and outputs the total value as a current reference value of the loop car drive motor to an automatic current control device of the motor; Loop car tension control device for continuous steel strip processing line consisting of.