JPH02290610A - Controller of rolling mill - Google Patents

Abstract

PURPOSE:To correct to an intended rolling state and to hold its state, when the rolling state is not appropriate by holding an output of a tension controller to a value at the time of starting an adjustment, when a speed fine adjustment device is being adjusted, and setting a tension detection value at the time when a fine adjustment is completed to the subsequent target material tension. CONSTITUTION:While an operator is adjusting a speed fine adjustment device 7, an output of a tension controller 17 is held to a value at the time of starting an adjustment. As a result, an interference between the speed fine adjustment quantity and the speed correction quantity is prevented. Also, a tension detection value at the time when an adjustment of the speed fine adjustment device 7 is completed is set to subsequent target material tension. In such a way, it can be prevented that a rolling state of a rolling mill returns to a state before the adjustment. Accordingly, the rolling state is corrected easily to the rolling state intended by the operator, and also, this rolling state can be held.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a control device for a continuous rolling mill that continuously rolls N4 temporary steel bars, etc.

(Prior Art) Controlling the tension acting on a rolled material in a continuous rolling mill to be constant or zero is an important element in improving rolling dimensional accuracy.

FIG. 2 is a block diagram showing the configuration of a conventional rolling mill control device that performs this type of control. In the figure, when the rolled material is continuously rolled in the order of stand i-1, stand i, and stand l11, the rolling mills 8 of each stand are driven by electric motors 9 each having a speed control device 10. In this case, the speed control device 10 of each stand has the speed reference of the speed reference generator 18, the speed correction applied to the speed control device 10 of the front stand seen in the moving direction of the rolled material, and the tension of the own stand. A speed correction amount ΔN outputted by the control device 11 and a speed fine adjustment amount obtained by adding the speed correction amount ΔN' made by the operator using the speed fine adjuster 7 are added. In addition, the tension control device 17 of each stand is
The speed correction amount ΔN is calculated using the so-called rear tension TB calculated by the tension detector 11 of the rear stand.

Although various methods can be used to detect the inter-stand tension, the present invention will be explained by taking as an example a detection method using rolling load and rolling torque.

Figure 3 shows the relationship between the signal output of this tension detection method, especially for the i-stand, where the tension detector 11 detects the output signal of the load cell 12 that detects the rolling load and the rotation speed of the rolling mill. The output signal of the speed detector 13, the output signal of the current detector 14 that detects the armature current of the electric motor 9, and the rear tension signal are input, and the tension detector 11 calculates the tension between the stands based on these signals. The tension calculation circuit 4 calculates the deviation from the tension set by the target tension setting device 6. Next, the tension deviation is proportionally integrated in a proportional integration circuit 5 and outputted as a speed correction ΔN.

FIG. 4 is a block diagram showing the detailed configuration of the tension control device 11, which calculates the motor output torque based on the rolling load PS, the armature current I of the motor 9, and the rotation speed N of the rolling mill. Using an acceleration/deceleration current removal device 1 that calculates the acceleration/deceleration torque of the electric motor, and each torque and rear tension TB determined by this acceleration/deceleration current removal device 1, the rolling torque GII1 is calculated, and the ratio with the rolling pressure P is calculated. That is, it is comprised of a torque arm lock-on calculation circuit 2 that calculates and outputs a torque arm, and a generated tension calculation circuit 3 that calculates inter-stand tension using this torque arm.

Next, the operation of the control device for this rolling mill will be explained.

When the material to be rolled is caught in the i-stand and rolling is started, the armature current I of the electric motor 9 increases rapidly. This current is detected by the current detector 14, and at the same time, the rolling pressure P is detected by the load cell 12, and the rotation speed N of the rolling mill is detected.
are detected by the speed detector 13 and input to the acceleration/deceleration current removing device 1, respectively.

The armature current l input to the acceleration/deceleration current removal device 1 includes not only the rolling torque current required for pure rolling, but also the acceleration/deceleration torque current required to accelerate/decelerate the rolling mill 8 and electric motor 9 and the friction torque of the machine. Contains branch current. Therefore,
To find the rolling torque G, the following equation must be calculated.

・・・・・・(1) however, ■=Armature voltage ■: Armature current N: Rolling mill rotation speed R: Armature resistance TB: Back tension K1 to K5: Constant It is.

The first term on the right side of equation (1) above is the motor output torque, and the second term is
The term means acceleration/deceleration torque, the third term means friction torque, and the fourth term means 1.Luke due to rear tension.

Next, the torque arm lock-on calculation circuit 2 calculates the period from when the tip of the material to be rolled is bit into the 1st stand until just before it reaches the i11 stand, that is, between the i stand and the i+1 stand.
During the period when the tension generated in the material to be rolled between the stands is zero, the rolling torque G is calculated multiple times using equation (1), and the ratio G /P of these m rolling torque G and rolling load P is calculated. 1

Find the average value a using the following formula. Calculate.

This is in accordance with the rolling theory that the ratio between the rolling pressure P applied to the rolling stand holding the rolled material and the pure rolling torque G required for rolling is constant regardless of the rolling state. So, this average value a. is called a torque arm.

When the rolled material advances further and its tip is bitten by the i+1 stand, a tension T is generated between the i stand and the i11 stand. Calculate.

ao P G・・・・・・・(3) TrA- K7 however, K7: Constant It is.

Next, the tension calculation circuit 4 calculates the tension setting value T of the target tension setting device 6, which sets the tension between the i stand and the i+l stand.

, and the tension T calculated by the generated tension calculation circuit 3, the deviation ΔT is calculated using the following equation.

m ΔT−TO+ 1Tref “””('
) Next, the proportional-integral circuit 5 converts the tension deviation ΔT obtained by this equation (4) into a speed correction amount ΔN, adds it to the similar speed correction 2 of the front stand i+1, and calculates the speed control device 10.
will be given to.

The acceleration/deceleration current removing device 1 in FIG. 4 performs calculations on the first to third terms on the right side of equation (1), and delivers the calculation results to the torque arm lock-on calculation circuit 2. The torque arm lock-on calculation circuit 2 calculates the rolling torque G based on the equation (1), then calculates the ratio between the rolling torque G and the rolling pressure mP, and calculates the rolling torque G based on the equation (2). The torque arm aO of the stand is calculated and stored.The generated tension calculation circuit 3 calculates the tension T generated between the stands by calculating the equation (3) m.Then, the tension calculation circuit 4 calculates (4) ) The tension deviation ΔT given by the equation is calculated.The proportional-integral circuit 5 proportionally and integrally integrates this tension deviation ΔT and outputs a speed correction amount ΔN.

In this way, by using the calculated and memorized torque arm, it is possible to control the inter-stand tension in front of the own stand to be constant or zero after the tip of the material to be rolled is bitten into the adjacent stand.

(Problems to be Solved by the Invention) In the conventional rolling mill control device described above, a case has been described in which the tension between the rolling mills is detected using the rolling load and rolling torque, but other tension detection methods may be used. Even if this is adopted, it is possible that an error will occur in the travel force. If an error occurs in the detected tension in this way, the speed correction amount ΔN output from the tension control device 17 will not be appropriate and will have an adverse effect on the rolled material.

In this way, when an adverse effect appears on the rolled material due to tension detection error, etc., the operator who is supervising the rolling condition adjusts the speed fine adjustment amount ΔN' using the speed fine adjuster 7 to correct the rolling mill speed ( (hereinafter referred to as speed correction intervention). However, since the speed fine adjustment amount ΔN' of the speed fine adjuster 7 and the speed correction amount ΔN outputted from the tension control device 17 interfere with each other, it is not easy for the operator to correct the speed.

Furthermore, after the speed correction intervention is completed, the speed correction amount ΔN of the tension control device 17 causes the rolling state to return to the state before the speed correction intervention, and even if the rolling state is corrected to the one intended by the operator, that state is maintained. It was difficult.

This invention was made to solve the above problems, and when the rolling condition of the rolled material is not appropriate due to tension detection error of the tension control device, etc., the rolling condition of the product is corrected to the rolling condition intended by the operator. It is an object of the present invention to provide a control device for a rolling mill that can maintain this state.

[Structure of the invention]

(Means for Solving the Problems) This invention includes a tension detector that detects material tension between rolling mills and a tension setting device that sets a target material tension, and speed correction of the rolling mill corresponding to each output deviation. a tension control device that calculates a quantity, a speed reference generator that generates a speed reference for the rolling mill, a speed fine adjuster that corrects the speed reference by an adjustment operation, and a rolling mill drive according to the corrected speed reference. In a control device for a rolling mill that is equipped with a speed control device that controls the speed of the electric motor and performs correction control so as to make the speed correction amount zero, the tension control device is not operated during adjustment of the speed fine adjuster. A speed correction amount holding means for holding the output at the value at the start of adjustment, and a means for storing the tension detection value when the adjustment of the speed fine adjuster is completed, so that the stored value is applied instead of the output of the tension setting device. and target tension value switching means for switching the circuit.

(Function) In this invention, while the operator is adjusting the speed fine adjuster, the output of the tension control device is held at the value at the start of adjustment, thereby preventing interference between the speed fine adjustment and the speed correction amount. Furthermore, by setting the tension detection value at the time of completion of the adjustment of the speed fine adjuster as the subsequent target material tension, it is possible to prevent the rolling state of the rolling mill from returning to the state before adjustment. It is possible to correct the rolling state to the one intended by the operator and to maintain this rolling state.

(Embodiment) FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. In the figure, the same elements as in FIG. 2 are given the same reference numerals, and the explanation thereof will be omitted.

Here, with respect to the configuration shown in FIG. 2, a speed correction amount holding circuit 16 that maintains the speed correction amount ΔN outputted by the tension control device 17 at the same value at the start of adjustment while adjusting the speed fine adjuster 7 is used. and a floating tension value switching circuit which stores the tension detection value of the tension detector 11 at the end of the adjustment with the speed fine adjuster 7, and applies this stored value to the tension calculation circuit 4 as the target tension setting value after the adjustment is completed. 15 is added.

The operation of this embodiment configured as described above will be explained below, focusing particularly on the part where new elements are added.

First, if an error or the like is included in the tension detection between the rolling mills, the speed correction amount ΔN from the tension control device 17 to the rolling mill 8 acts on the rolled material so that an unreasonable force is exerted on the rolled material. This adversely affects the finished diameter of the rolled material.

The operator then performs a speed correction intervention on the rolling mill, ie adjusts the speed fine adjuster 7. In this manner, while the operator is adjusting the speed fine adjuster 7, the speed correction amount holding circuit 16 maintains the speed reversal correction amount ΔN at the value at the start of the adjustment. This avoids mutual interference with the speed fine adjustment amount ΔN'.

Next, when the operator's fine adjustment operation for the AJ adjuster 7 is completed, the fine adjustment signal disappears, so the speed correction amount holding circuit 16 captures this as a speed fine adjustment completion signal and detects the tension at this point. The tension setting device 6 stores the value and uses this stored value as the target tension from then on.
Add the tension force to 30 circuits 4 instead of .

As a result, the problem of the conventional apparatus in which the rolled shape of the rolling mill returns to the state before the speed correction intervention due to the speed correction amount ΔN after the operator intervenes in the speed correction is solved.

〔Effect of the invention〕

As is clear from the above explanation, according to this invention,
During the adjustment of the speed fine adjuster, there is a speed correction amount holding means that holds the output of the tension control device at the value at the start of adjustment, and a tension detection value when the adjustment of the speed fine adjuster is completed, and the stored value is used as the tension. Since it is equipped with a target tension value switching means that switches the circuit so that the tension is applied instead of the output of the setting device, if a rolling condition that adversely affects the rolled material occurs due to an error in the rolling mill tension, etc. This has the effect that the operator can easily correct the rolling condition of the rolling mill, and that the rolling condition intended by the operator can be maintained even after the speed correction intervention.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a block diagram showing a conventional rolling mill control device, and Fig. 3 shows the relationship between signal input and output of the tension detector that constitutes this device. FIG. 4 is a block diagram showing the detailed configuration of this tension detector. 4...Tension calculation circuit, 5...Proportional integral circuit, 6...
・Tension setting device, 7...Speed fine adjuster, 8...Rolling machine, 9...Electric motor, 10...Speed control device, 11...
Tension detector, 15...Target tension value switching circuit, 16...
・Speed correction amount holding circuit, 17...Tension control device, 18
...Speed reference generator.

Claims (1)

[Claims] a tension control device that includes a tension detector that detects material tension between rolling mills and a tension setting device that sets a target material tension, and that computes a speed correction amount of the rolling mill corresponding to each output deviation;
a speed reference generator that generates a speed reference for the rolling mill; a speed fine adjuster that corrects the speed reference by an adjustment operation; and a speed fine adjuster that controls the speed of the rolling mill drive motor according to the corrected speed reference; In a rolling mill control device comprising a speed control device that performs correction control so as to make the correction amount zero, the speed maintains the output of the tension control device at the value at the start of adjustment during adjustment of the speed fine adjuster. correction amount holding means; and target tension value switching means for storing the detected tension value at the time of completion of adjustment of the speed fine adjuster and switching a circuit so that the stored value is applied instead of the output of the tension setting device. A control device for a rolling mill characterized by comprising: