JP7709030B2 - Processing device, processing method, and program - Google Patents

Description

The present invention relates to a processing device, a processing method, and a program.

Hot-rolled thin steel sheets are manufactured in the following process. First, a slab, which is a rolled material, is heated in a heating furnace. The slab is then rough-rolled in a rough rolling mill to produce a rough bar. The rough bar is then finish-rolled in a finishing tandem rolling mill equipped with multiple rolling stands. In this way, hot-rolled thin steel sheets are manufactured. In the finishing rolling, the temperature of the rolled material is controlled at the exit position (temperature control position) of the finishing tandem rolling mill in order to ensure the mechanical properties of the rolled material, such as strength and ductility. As temperature control devices for adjusting the temperature of the rolled material, for example, a rough bar heating device that heats the rough bar between the rough rolling mill and the finishing tandem rolling mill, a rough bar cooling device that cools the rough bar between the rough rolling mill and the finishing tandem rolling mill, and a cooling spray device that cools the rolled material between the rolling stands of the finishing tandem rolling mill are used.

As a method for controlling the temperature of the rolled material during such finish rolling, there are techniques disclosed in Patent Documents 1 to 3.
In the method disclosed in Patent Document 1, a plurality of control points are set on the rough bar in the rolling direction, the temperature of each control point at the exit side of the roughing mill is measured, and the temperature of each control point at the exit side of the finishing tandem rolling mill is predicted based on the measured temperature, and the rough bar heater and the cooling spray device are operated so that the predicted temperature of each control point at the exit side of the finishing tandem rolling mill becomes the target temperature. However, the control by this method is a feedforward control of the temperature of the rolled material at the exit side of the roughing mill. Therefore, if there is an error in the predicted temperature of each control point, the temperature of the finish tandem rolling mill exit side at each control point does not match the target temperature. Therefore, in the methods disclosed in Patent Documents 2 and 3, the temperature of the rolled material at the exit side of the finishing tandem rolling mill is controlled by combining feedforward control and feedback control of the temperature of the rolled material at the exit side of the finishing tandem rolling mill.

JP 2002-219504 A Patent No. 3657750 Patent No. 4425978

However, the feedback control disclosed in Patent Documents 2 and 3 corrects the manipulated variable of the temperature control device by proportional integral control of the deviation between the measured value and the target value of the temperature of the rolled material at the exit side of the finishing tandem rolling mill. When performing feedback control based on the deviation between the measured value and the target value, the important thing is the dead time from when the manipulated variable is corrected until the result appears in the measured value. The smaller this dead time is, the easier it is to make the control highly responsive. Therefore, in the feedback control disclosed in Patent Document 2, the manipulated variable is corrected preferentially from the temperature control device located downstream among multiple temperature control devices. However, when the temperature of the rolled material changes, the thicker the plate is, the less likely it is that the shape of the rolled material will change. From this perspective, it is desirable to use the temperature control device located upstream preferentially, and in fact, this is done in the feedforward control disclosed in Patent Documents 2 and 3. Therefore, when the feedback control disclosed in Patent Document 2 is applied, the dead time is reduced, but there is a risk that the shape of the rolled material will deteriorate.

Therefore, in the feedback control disclosed in Patent Document 3, the manipulated variable of the temperature control device located at the most upstream among the temperature control devices that have not reached the saturated state is corrected. However, in this method, the shape of the rolled material is less likely to deteriorate compared to the method disclosed in Patent Document 2, but the dead time becomes longer, making it difficult to achieve high-response control.
As described above, the method of feeding back the deviation between the measured value and the target value of the temperature of the rolled material at the exit of the finishing tandem rolling mill to the manipulated variable of the temperature control device cannot simultaneously suppress deterioration of the shape of the rolled material and improve the response of the temperature control.

The present invention was made in consideration of these problems, and aims to achieve both prevention of deterioration of the shape of the rolled material and high response of temperature control when controlling the temperature of the rolled material at the exit side of the finishing rolling mill.

The processing device of the present invention is a processing device that determines an operation amount of a temperature adjustment device that adjusts the temperature of a rolled material being transported between the exit side of a roughing rolling mill and the exit side of a finishing rolling mill, and includes a finish rolling mill exit temperature acquisition means that acquires a measured value of a finish rolling mill exit temperature, which is the temperature of the rolled material at the exit side of the finishing rolling mill, a temperature calculation means that calculates a calculated value of the finish rolling mill exit temperature based on the latest value of the operation amount of the temperature adjustment device, a correction amount calculation means that calculates a correction amount of the finish rolling mill exit temperature based on the measured value of the finish rolling mill exit temperature acquired by the finish rolling mill exit temperature acquisition means and the calculated value of the finish rolling mill exit temperature calculated by the temperature calculation means, and an operation amount determination means that determines an operation amount of the temperature adjustment device for the rolled material for which the measured value of the finish rolling mill exit temperature has been acquired based on the correction amount of the finish rolling mill exit temperature, and When a measured value of the finishing rolling mill outlet temperature at one of the control points is obtained, the temperature calculation means calculates a calculated value of the finishing rolling mill outlet temperature at that control point, the correction amount calculation means calculates a correction amount for the finishing rolling mill outlet temperature at that control point based on the measured value of the finishing rolling mill outlet temperature at the control point and the calculated value of the finishing rolling mill outlet temperature at that control point, the operation amount determination means determines operation amounts of the temperature adjustment devices for all of the control points located downstream of the control point that is located at the measurement position of the finishing rolling mill outlet temperature based on the correction amount of the finishing rolling mill outlet temperature at the control point, and the operation amount determination means identifies a temperature adjustment device downstream of the position where the control point is located for all of the control points located downstream of the control point that is located at the measurement position of the finishing rolling mill outlet temperature, and updates only the operation amount of the temperature adjustment device downstream of the position where the control point is located .

The processing method of the present invention is a processing method for determining an operation amount of a temperature adjustment device that adjusts the temperature of a rolled material being transported between the exit side of a roughing rolling mill and the exit side of a finishing rolling mill, and includes a finishing rolling mill exit temperature acquisition step of acquiring a measured value of a finishing rolling mill exit temperature, which is the temperature of the rolled material at the exit side of the finishing rolling mill, a temperature calculation step of calculating a calculated value of the finishing rolling mill exit temperature based on the latest value of the operation amount of the temperature adjustment device, a correction amount calculation step of calculating a correction amount of the finishing rolling mill exit temperature based on the measured value of the finishing rolling mill exit temperature acquired by the finishing rolling mill exit temperature acquisition step and the calculated value of the finishing rolling mill exit temperature calculated by the temperature calculation step, and an operation amount determination step of determining an operation amount of the temperature adjustment device for the rolled material for which the measured value of the finishing rolling mill exit temperature has been acquired based on the correction amount of the finishing rolling mill exit temperature, In the temperature calculation step, when a measured value of the finishing rolling mill outlet temperature at one of the control points is obtained, a calculated value of the finishing rolling mill outlet temperature at that control point is calculated, and in the correction amount calculation step, a correction amount for the finishing rolling mill outlet temperature at that control point is calculated based on the measured value of the finishing rolling mill outlet temperature at the control point and the calculated value of the finishing rolling mill outlet temperature at that control point. In the operation amount determination step, an operation amount of the temperature adjustment device for all of the control points located downstream of the control point that is located at the measurement position of the finishing rolling mill outlet temperature is determined based on the correction amount of the finishing rolling mill outlet temperature at the control point, and in the operation amount determination step, for all of the control points located downstream of the control point that is located at the measurement position of the finishing rolling mill outlet temperature, a temperature adjustment device located downstream of the control point is identified, and only the operation amount of the temperature adjustment device located downstream of the control point is updated .

The program of the present invention is intended to cause each means to function as the processing device.

According to the present invention, the correction amount for the finishing mill exit temperature is calculated based on the measured value of the finishing mill exit temperature and the calculated value of the finishing mill exit temperature, and the operation amount of the temperature control device is determined based on the correction amount of the finishing mill exit temperature. Therefore, as in the case of performing feedforward control, operation can be performed from the temperature control device located upstream. Also, unlike the method of feedback control based on the temperature deviation between the measured value of the finishing mill exit temperature and the target value, feedback control can be performed without being affected by dead time. Therefore, when controlling the temperature of the rolled material at the exit of the finishing mill, it is possible to achieve both suppression of deterioration of the shape of the rolled material and high response of temperature control.

FIG. 1 is a diagram showing an example of a configuration of rolling equipment. FIG. 4 is a diagram illustrating an example of a control point. FIG. 2 is a diagram illustrating an example of a functional configuration of a processing device. 11 is a flowchart illustrating an example of a feedforward control process. 10 is a flowchart illustrating an example of a feedback control process. FIG. 4 is a diagram showing an example of a roughing mill delivery side temperature. FIG. 13 is a diagram showing the conditions and results of a simulation of Comparative Example 1. FIG. 13 is a diagram showing the conditions and results of a simulation of Comparative Example 2. FIG. 13 is a diagram showing the conditions and results of a simulation of an example of the invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In addition, when comparing objects with each other, such as length, position, size, spacing, etc., being the same, this includes not only objects that are strictly the same, but also objects that are different within the scope of the invention (for example, objects that differ within the tolerance range determined at the time of design).
<Rolling equipment 100>
FIG. 1 is a diagram showing an example of the configuration of a rolling facility 100.
The rolling equipment 100 rolls the rolled material 1 on a transport path R formed in the rolling equipment 100. The transport path R is a space formed in the rolling equipment 100 for transporting and rolling the rolled material 1 from the upstream side D1 to the downstream side D2 in the transport direction D.

The rolling equipment 100 includes a roughing mill 10, a finishing tandem mill (finishing mill) 20, a tracking device 30, a rough bar cooling device 40, cooling spray devices 51 to 56, a roughing mill exit thermometer 60, and a finishing mill exit thermometer 70.
The roughing mill 10 and the finishing tandem rolling mill 20 each roll the rolled material 1 on the transport path R. The roughing mill 10 roughly rolls the rolled material 1. The rolled material 1 rough rolled by the roughing mill 10 is also called a rough bar. The finishing tandem rolling mill 20 is installed downstream D2 of the roughing mill 10 in the transport direction D. The finishing tandem rolling mill 20 finishes rolling the rolled material 1 rough rolled by the roughing mill 10. The finishing tandem rolling mill 20 includes a plurality of rolling stands (rolling mills) F1 to F7 (seven in this embodiment). The rolling stands F1 to F7 are installed in the order of rolling stand F1, rolling stand F2, ..., rolling stand F7 from the upstream side D1 to the downstream side D2 of the transport direction D.

On the rolled material 1, a plurality of control points are set at intervals in the conveying direction D. FIG. 2 is a diagram for explaining an example of a control point. In FIG. 2, the position of the tip of the arrow line indicates the control point. The control point indicates a temperature control position (control point) on the rolled material 1 (the rolled material 1 does not have information indicating the control point). Here, of the plurality of control points, the kth control point from the downstream side D2 toward the upstream side D1 of the conveying direction D is referred to as the kth control point. The number of the plurality of control points is N. That is, k is an integer between 1 and N. For example, in FIG. 2, the position of the tip of the arrow line shown below k=1 indicates the first control point. Similarly, the positions of the tips of the arrow lines shown below k=2, 3, ..., N-2, N-1, N indicate the second control point, the third control point, ..., the N-2 control point, the N-1 control point, and the Nth control point, respectively.

Figure 2 illustrates an example in which the first control point is the position of the leading edge of the rolled material 1, and the Nth control point is the position of the trailing edge of the rolled material 1. Figure 2 also illustrates an example in which the distance between two adjacent control points in the conveying direction D is equal. In this way, it is preferable that the multiple control points are set at a constant pitch from the leading edge to the trailing edge in the conveying direction D of the rolled material 1. However, as long as multiple positions are set as multiple control points as positions in the conveying direction D on the rolled material 1 where temperature control is performed, the multiple control points do not necessarily have to be set as shown in Figure 2.

The roughing mill exit thermometer 60 is installed at the exit (downstream D2) of the roughing mill 10. The exit of the roughing mill 10 refers to the downstream D2 of the roughing mill 10 and the upstream D1 of the rough bar cooling device 40, which is the most upstream temperature adjustment device. The roughing mill exit thermometer 60 measures the temperature of the rolled material 1 at the exit of the roughing mill 10 and outputs it to the processing device 80. The temperature measured by the roughing mill exit thermometer 60 is also referred to as the roughing mill exit temperature. The finishing mill exit thermometer 70 is installed at the exit of the finishing tandem rolling mill 20. The exit side of the finishing tandem rolling mill 20 refers to the downstream side D2 of the finishing tandem rolling mill 20 (the most downstream rolling stand F7) and the upstream side D1 of a coiler (not shown) (a device that winds up the rolled material 1 after finish rolling). A specific example of the upstream side D1 of the coiler (not shown) is, for example, the upstream side D1 of a hot run spray (not shown) for cooling the rolled material 1 after finish rolling before winding by the coiler. The finishing rolling mill exit side thermometer 70 measures the temperature of the rolled material 1 at the exit side of the finishing tandem rolling mill 20 and outputs it to the processing device 80. The temperature measured by the finishing rolling mill exit side thermometer 70 is also referred to as the finishing rolling mill exit side temperature.

The rough bar cooling device 40 and the cooling spray devices 51-56 are examples of temperature control devices that adjust the temperature of the rolled material 1 being transported between the exit side of the roughing mill 10 and the exit side of the finishing tandem mill 20. The rough bar cooling device 40 is installed between the roughing mill exit side thermometer 60 and the finishing tandem mill 20. The cooling spray devices 51, 52, 53, 54, 55, and 56 are installed at the exit sides of the rolling stands F1, F2, F3, F4, F5, and F6, respectively. Here, the numbers 1 to 7 following the F in the rolling stands F1 to F7 are represented by i. The exit side of the rolling stand Fi refers to the downstream side D2 of the rolling stand Fi and the upstream side D1 of the rolling stand Fi+1. For example, the exit position of rolling stand F1 (Fi) is downstream D2 of rolling stand F1 (=Fi) and upstream D1 of rolling stand F2 (=Fi+1).

The coarse bar cooling device 40 and the cooling spray devices 51 to 56 are devices that adjust the flow rate of cooling water by manipulating the valve opening degree to supply cooling water to the rolled material 1, thereby cooling the rolled material 1.
The temperature adjustment devices are not limited to the coarse bar cooling device 40 and the cooling spray devices 51 to 56. For example, only one of the coarse bar cooling device 40 and the cooling spray devices 51 to 56 may be installed. In addition to these temperature adjustment devices, a temperature adjustment device for heating the rolled material 1 may be installed at each installation position on the transport path R.

Here, the coarse bar cooling device 40 and the cooling spray devices 51 to 56 are also referred to as the jth temperature control device. j is an integer between 1 and 7 (7 is the total number of cooling control devices). Here, positive integers are assigned to j in ascending order from the temperature control device located on the upstream side D1 of the conveying direction D. Therefore, j=1 is assigned to the coarse bar cooling device 40 (the coarse bar cooling device 40 becomes the first temperature control device). j=2, 3, 4, 5, 6, 7 are assigned to the cooling spray devices 51, 52, 53, 54, 55, 56, respectively (the cooling spray devices 51, 52, 53, 54, 55, 56 become the second, third, fourth, fifth, sixth, and seventh temperature control devices, respectively). The method of ordering the multiple temperature control devices is not particularly limited. In addition, in the following description, when the i+1th temperature control device is referred to, the i+1th temperature control device refers to the cooling spray device 51, 52, 53, 54, 55, or 56 installed at the exit position of the rolling stand Fi.

The tracking device 30 momentarily tracks the position of each control point of the rolled material 1 in the conveying direction D, generates tracking information including the position information and information indicating whether a control point of the rolled material 1 has newly reached the installation position in the conveying direction D of the roughing mill exit thermometer 60, the first to seventh temperature control devices 40, 51 to 56, and the finishing rolling mill exit thermometer 70, and outputs the tracking information to the processing device 80 and the first to seventh temperature control devices 40, 51 to 56. The tracking of the position of each control point of the rolled material 1 in the conveying direction D is performed by using, for example, the rolling speed of the roughing mill 10, the rolling speed of the finishing tandem rolling mill 20, and the conveying speed of the rolled material 1 between the roughing mill 10 and the finishing tandem rolling mill 20. Here, whether or not the position has been newly reached does not mean whether or not the position has been reached at the current time, but means whether or not a change in the state of arrival has occurred, that is, the position has been reached in the current sampling period, although the position has not been reached in the previous sampling period of the tracking device 30. The hardware of the tracking device 30 is realized, for example, by using an information processing device having a processor, a main memory device, an auxiliary memory device, and various interfaces, a programmable logic controller, or dedicated hardware. In the following description, the installation position in the conveying direction D is also simply referred to as the installation position. In addition, the method of tracking the position of the rolled material 1 by the tracking device 30 itself can be realized by a known method, so a detailed description thereof will be omitted here.

The processing device 80 executes processes including calculating a calculated value of the finishing mill outlet temperature, calculating a correction amount for the finishing mill outlet temperature based on the calculated calculated value of the finishing mill outlet temperature and the measured value of the finishing mill outlet temperature, and determining an operation amount of the temperature control device based on the calculated correction amount for the finishing mill outlet temperature.

In this embodiment, the processing device 80 determines the operation amount of the first to seventh temperature control devices for each control point of the rolled material 1. The processing device 80 samples the rough rolling mill outlet temperature at each control point of the rolled material 1 measured by the rough rolling mill outlet thermometer 60. The processing device 80 also samples the finish rolling mill outlet temperature at each control point of the rolled material 1 measured by the finish rolling mill outlet thermometer 70. The processing device 80 also calculates the calculated value of the finish rolling mill outlet temperature at each control point of the rolled material 1. For example, the processing device 80 calculates the calculated value of the finish rolling mill outlet temperature at the control point of the rolled material 1 based on the latest value of the operation amount of the temperature control device for the control point of the rolled material 1. The processing device 80 then calculates the correction amount of the finish rolling mill outlet temperature at the control point based on the measured value of the finish rolling mill outlet temperature at the control point of the rolled material 1 and the calculated value of the finish rolling mill outlet temperature at the control point.

Then, the processing device 80 determines the operation amount of the temperature control device for each control point located on the rear end side of the rolled material 1 from the control point based on the correction amount of the finish rolling mill outlet temperature at the control point. For example, the processing device 80 determines the operation amount of the temperature control device for each control point located on the rear end side of the rolled material 1 from the control point so that the finish rolling mill outlet temperature corrected by the correction amount of the finish rolling mill outlet temperature at the control point satisfies a predetermined temperature condition. An example of the predetermined temperature condition is that the corrected finish rolling mill outlet temperature is a predetermined value or within a predetermined range. The processing device 80 outputs the operation amount determined in this manner to the temperature control device that executes the operation of the operation amount. In this embodiment, the temperature control devices are the first to seventh temperature control devices 40, 51 to 56, and the operation amount is the valve opening. The hardware of the processing device 80 is realized, for example, by using an information processing device equipped with a processor, a main memory device, an auxiliary memory device, and various interfaces, or dedicated hardware such as a programmable logic controller or an ASIC (Application Specific Integrated Circuit).

The coarse bar cooling device 40 operates the valve opening degree of the coarse bar cooling device 40 based on the operation amount (valve opening degree of the coarse bar cooling device 40) for each control point of the rolled material 1 output from the processing device 80 and the tracking information output from the tracking device 30. The cooling spray devices 51 to 56 operate the valve opening degrees of the cooling spray devices 51 to 56 based on the operation amount (valve opening degree of the cooling spray devices 51 to 56) for each control point of the rolled material 1 output from the processing device 80 and the tracking information output from the tracking device 30.
In the present embodiment, the case where the temperature of the rolled material 1 is controlled as described above will be illustrated as an example.

<Functional configuration>
Next, an example of the functional configuration of the processing device 80 will be described with reference to FIG.
In this embodiment, an example is shown in which the processing device 80 is equipped with a finishing rolling mill outlet temperature acquisition unit 810, a rough rolling outlet temperature acquisition unit 820, an FF control unit 830 that performs processing for feedforward control of the temperature of the rolled material 1, and an FB control unit 840 that performs processing for feedback control of the temperature of the rolled material 1.

<Finishing rolling mill delivery temperature acquisition unit 810>
When the tracking device 30 gives the finishing mill outlet temperature acquisition unit 810 tracking information that the control point of the rolled material 1 has newly arrived at the installation position of the finishing mill outlet thermometer 70, the finishing mill outlet temperature acquisition unit 810 samples the measured value of the finishing mill outlet temperature at the control point of the rolled material 1 from the finishing mill outlet temperature measured by the finishing mill outlet thermometer 70. In the following description, the symbol indicating the measured value of the finishing mill outlet temperature at the nth control point (n = 1 to N) of the rolled material 1 is represented as θ _F,n . n is the sampling number of the measured value of the finishing mill outlet temperature, and is an integer of 1 to N (1 ≦ n ≦ N). In this embodiment, the measured value of the finishing mill outlet temperature at each control point of the rolled material 1 is sampled, so n indicates the control point of the rolled material 1.

<Roughing mill outlet temperature acquisition unit 820>
When the tracking information that the control point of the rolled material 1 has newly arrived at the installation position of the rough rolling mill outlet thermometer 60 is given from the tracking device 30, the rough rolling mill outlet temperature acquisition unit 820 samples the measurement value of the rough rolling mill outlet temperature at the control point of the rolled material 1 from the rough rolling mill outlet temperature measured by the rough rolling mill outlet thermometer 60. In the following description, the symbol indicating the measurement value of the rough rolling mill outlet temperature at the kth control point of the rolled material 1 is expressed as θ _R,k . k is the sampling number of the measurement value of the rough rolling mill outlet temperature, and is an integer of 1 to N (1≦k≦N). In this embodiment, the measurement value of the rough rolling mill outlet temperature of each control point of the rolled material 1 is sampled, so k indicates the control point of the rolled material 1.

<FF control unit 830>
The FF control unit 830 calculates the initial values of the manipulated variables of the first to seventh temperature control devices 40, 51 to 56 for each control point based on the measured value θ _R,k of the roughing mill exit temperature. This corresponds to feedforward control using the measured value θ _R,k of the roughing mill exit temperature. Such feedforward control may be realized by a known method described in Patent Document 1, for example, but in this embodiment, a case in which the initial values of the manipulated variables of the first to seventh temperature control devices 40, 51 to 56 for each control point are calculated by a method using mathematical programming is illustrated. The FF control unit 830 executes such calculation of the initial values every time it is determined that each control point of the rolling material 1 has newly reached the installation position of the roughing mill exit thermometer 60 based on the tracking information output from the tracking device 30. Below, an example of the detailed function of the FF control unit 830 will be described assuming that the kth control point of the rolling material 1 has newly reached the installation position of the roughing mill exit thermometer 60. In this embodiment, the FF control unit 830 includes an initial value calculation unit 831 and an output unit 832 .

<<Initial Value Calculation Unit 831>>
The initial value calculation unit 831 calculates initial values of the manipulated variables of the first to seventh temperature control devices 40, 51 to 56 for the k-th control point of the rolled material 1 based on the measured value θ _R,k of the roughing mill delivery temperature at the k-th control point of the rolled material 1. The initial value calculation unit 831 also calculates initial values of the calculated values of the finishing mill delivery temperature at the k-th control point that are achieved by manipulating the initial values. An example of the detailed functions of the initial value calculation unit 831 will be described below.

First, the initial value calculation unit 831 calculates (predicts) the finishing mill exit temperature T- _k at the kth control point of the rolling material 1 by performing a temperature calculation for the kth control point of the rolling material 1 when the valve openings (operation amounts) of the first to seventh temperature control devices 40, 51 to 56 are set to 0 (zero) based on the measured value θ R, _k of the roughing mill exit temperature at the kth control point of the rolling material 1. Setting the operation amounts of the first to seventh temperature control devices 40, 51 to 56 to 0 (zero) means that no temperature control is performed in any of the first to seventh temperature control devices 40, 51 to 56. The symbol T- corresponds to the symbol with - above T in each formula described later. In the following description, the finishing mill exit temperature T- _k at the kth control point is also referred to as the reference temperature T- _k . For this temperature calculation, a known calculation method described in, for example, JP 2008-221232 A can be used.

Next, the initial value calculation unit 831 calculates (predicts ₎ the finish rolling mill exit temperature at the kth control point of the rolled material 1 when the valve opening (operation amount) of the coarse bar cooling device 40 is maximized and the valve opening (operation amount) other than the coarse bar cooling device 40 is set to 0 (zero) based on the measured value θ R,k of the rough rolling mill exit temperature at the kth control point of the rolled material 1. The initial value calculation unit 831 calculates the value obtained by subtracting the reference temperature T- _k from the calculated finish rolling mill exit temperature at the kth control point as the maximum temperature changeable amount ΔT _k,1 of the coarse bar cooling device 40. Since the coarse bar cooling device 40 is a cooling device, the value of the maximum temperature changeable amount ΔT _k,1 of the coarse bar cooling device 40 is negative. The maximum temperature changeable amount ΔT _k,1 of the rough bar cooling device 40 is the temperature difference by which the rough bar cooling device 40, which is the first temperature adjustment device, can adjust the finish rolling mill exit temperature at the kth control point of the rolled material 1 with the largest change range.

Further, the initial value calculation unit 831 calculates (predicts) the finishing mill delivery temperature at the kth control point of the rolled material ₁ when the valve opening (operation amount) of the cooling spray device 50+i (51 (=50+1), 52 (=50+2), 53 (=50+3), 54 (=50+4), 55 (=50+5), 56 (=50+6)) installed at the exit position of the rolling stand Fi (i=1 to 6) is maximized and the valve opening (operation amount) of the cooling spray device 50+i other than the cooling spray device 50+i is set to 0 (zero) based on the roughing mill delivery temperature θ R,k at the kth control point. The initial value calculation unit 831 calculates the value obtained by subtracting the reference temperature T− _k from the calculated finishing mill delivery temperature at the kth control point as the maximum temperature changeable amount ΔT _k,i+1 of the cooling spray device 50+i. Since the cooling spray devices 51 to 56 are cooling devices, the maximum temperature changeable amount ΔT _k,i+1 (i=1 to 6) of the cooling spray device 50+i is negative. Note that 50+i indicates that it is one of the symbols 51, 52, 53, 54, 55, and 56 attached to FIG. 1 according to i (symbols may be expressed in the same manner hereinafter). The maximum temperature changeable amount ΔT _k,i+1 of the cooling spray device 50+i is the temperature difference with which the cooling spray device 50+i, which is the (i+1)th temperature adjustment device, can adjust the finish rolling mill delivery side temperature at the kth control point of the rolled material 1 with the largest change width. The temperature change caused by the rough bar cooling device 40 and the cooling spray devices 51 to 56 can be calculated using a known calculation method described in, for example, JP 2008-221232 A.

In the above manner, the reference temperature T− _k at the k-th control point of the rolled material 1, the maximum temperature changeable amount ΔT _k,1 of the coarse bar cooling device 40, and the maximum temperature changeable amount ΔT _k,i+1 of the cooling spray device 50+i (i=1 to 6) are calculated. Using these, the calculated value T _k of the finish rolling mill delivery temperature at the k-th control point of the rolled material 1 is expressed by the following formula (1).

Here, x _k,j is the operation ratio of the jth temperature control device to the kth control point of the rolled material 1, and the ratio is 0 when the operation amount of the jth temperature control device to the kth control point of the rolled material 1 is 0 (zero), and 1 when the operation amount is maximum. The operation ratio of the jth temperature control device to the kth control point of the rolled material 1 is the ratio of the temperature change of the kth control point of the rolled material 1 when the jth temperature control device is operated with the operation amount to be solved to the temperature change of the kth control point of the rolled material 1 when the jth temperature control device is operated with the maximum operation amount. Specifically, x _k,1 is the operation ratio of the coarse bar cooling device 40 to the kth control point of the rolled material 1. _{x k,i+1} (i=1 to 6) is the operation ratio of the cooling spray device 50+i to the kth control point of the rolled material 1. Since the operation amounts of the coarse bar cooling device 40 and the cooling spray devices 51 to 56 are continuous values, the following formula (2) is established.

The temperature condition that the finishing mill exit temperature at the kth control point of the rolled material 1 is equal to or higher than the lower limit temperature and equal to or lower than the upper limit temperature is expressed by the following inequality constraint equation (3).

Here, d and u are the lower limit temperature and the upper limit temperature of the finishing rolling machine exit temperature, respectively, and are determined in advance for each rolled material 1 based on the mechanical properties required for the rolled material 1. If the lower limit temperature constraint is unnecessary, the lower limit temperature can be set small, for example to 0°C, so that the lower limit temperature constraint is always satisfied. If the upper limit temperature constraint is unnecessary, the upper limit temperature can be set large, for example to 2000°C, so that the upper limit temperature constraint is always satisfied. If it is desired to match the target temperature of a predetermined value as closely as possible, rather than a range with a certain temperature width for the lower limit temperature and the upper limit temperature, the target temperature can be set for each of the lower limit temperature and the upper limit temperature.

As explained in the problem to be solved by the invention, when a temperature change occurs in the rolled material 1, the thicker the plate thickness of the rolled material 1, the less likely the shape of the rolled material 1 to change. For this reason, under the condition that the temperature constraint condition of the formula (3) is satisfied, it is desirable to use the temperature adjustment devices installed on the upstream side D1 of the conveying direction D in order. In this embodiment, it is desirable to use the temperature adjustment devices installed on the upstream side D1 of the conveying direction D preferentially among the coarse bar cooling device 40 and the cooling spray devices 51 to 56. Therefore, in this embodiment, as shown in the following formula (4), a case is illustrated in which an objective function J _k including an evaluation index for evaluating the order of use of the jth temperature adjustment device (the first to seventh temperature adjustment devices) to be used for the kth control point of the rolled material 1 is used.

Here, _wj is a positive weighting coefficient, and is set in advance so that _wj is in ascending order with respect to the subscript j ( _w1 < _w2 < ... < _w7 ). By reducing the value of the objective function _Jk in equation (4), the cooling adjustment device installed on the upstream side D1 in the conveying direction D can be used preferentially under the condition that the temperature constraint condition in equation (3) is satisfied. This makes it possible to make it difficult for the shape of the rolled material 1 to change.
The initial value calculation unit 831 calculates the operation ratio x k,j of the jth temperature control device for the kth control point of the rolled material 1, which minimizes the value of the objective function J _k in the formula (4) within a range satisfying the inequality constraint condition formulas of the formulas (2) and (3), by solving an optimization problem by mathematical programming, using the optimal solution x _{opt,k,j (} k = 1 to N, j = 1 to 7) of the operation ratio x _k,j of the jth temperature control device for the kth control point of the rolled material 1. The solution of the optimization problem by mathematical programming in this embodiment is realized, for example, by using a known solver for solving linear programming problems. Note that here, an example is shown in which the initial value calculation unit 831 solves a minimization problem that minimizes the value of the objective function J in the formula (4). However, for example, the initial value calculation unit 831 may solve a maximization problem. In this case, for example, the right side of the formula (4) multiplied by (-1) may be used as the objective function.

The initial value calculation unit 831 calculates the operation amount of the jth temperature control device based on the optimal value x _{opt,k,j (} k = 1 to N, j = 1 to 7) of the operation ratio x k,j of the jth temperature control device calculated as described above.
Here, the temperature change of the rolled material 1 with respect to the valve opening degree z ₁ of the coarse bar cooling device 40 can be expressed by, for example, the relationship as described in JP 2008-221232 A. Therefore, the temperature change of the rolled material 1 with respect to the valve opening degree z ₁ of the coarse bar cooling device 40 at the k-th control point is expressed as a function f ₁ (z _k,1 ). If the maximum valve opening degree of the coarse bar cooling device 40 is z _1max , the valve opening degree z _k,1 (operation amount) with respect to the k-th control point of the coarse bar cooling device 40 that satisfies the optimal solution x _opt,k,1 of the operation ratio x _k,1 of the coarse bar cooling device 40 is expressed by the following formula (5).

The initial value calculation unit 831 calculates the valve opening z _{k,1 ( k = 1 to N} ) of the coarse bar cooling device 40 for the kth control point of the rolled material 1 as a feedforward operation amount by solving equation (5) using the optimal solution x opt _,k,1 of the operation ratio x k,1 of the coarse bar cooling device 40.
Similar to the temperature change at the kth control point of the rolled material 1 with respect to the valve opening z ₁ of the rough bar cooling device 40, the temperature change at the kth control point of the rolled material 1 with respect to the valve opening z _i+1 of the cooling spray device 50+i installed at the exit side (i=1 to 6) of the rolling stand Fi is expressed as a function f _i+1 (z _i+1 ). If the maximum valve opening of the cooling spray device 50+i is z _(i+1)max , the valve opening z _k,i+ 1 (operation amount) of the cooling spray device 50+i that satisfies the optimal solution x _opt,k,i+1 of the operation ratio x _k,i+1 of the cooling spray device 50+i is expressed by the following equation (6).

The initial value calculation unit 831 calculates the valve opening z _{k,i+1 (k=1 to N, i=1 to 6) of the cooling spray device 50+i for the k-th control point of the rolled material 1 as a feedforward operation amount by solving the equation (6) using the optimal solution x opt,k,i +1} of the operation ratio x k,i+1 of the cooling spray device 50+i. In order to execute feedback control after the measured value of the finish rolling mill delivery temperature at the k-th control point of the rolled material 1 is obtained, the initial value calculation unit 831 sets the valve openings z _k,1 , z _{k,i+1 (k=} 1 to N, i=1 to 6) of the first to seventh temperature control devices 40, 51 to 56 calculated by the equations (5) and (6) as initial values z ⁽⁰⁾ _k, j (k=1 to N, j=1 to 7) of the valve openings (operation amounts) of the temperature control devices 40, 51 to 56 for the k-th control point. The initial value calculation unit 831 also initializes the initial value δ ⁽⁰⁾ of the correction amount δ of the finishing rolling mill delivery temperature to 0 (zero) (δ ⁽⁰⁾ = 0). The initial value calculation unit 831 also calculates an initial value T (0) cal _{,k of the calculated value T k} of the finishing rolling mill delivery temperature at the kth control point of the rolled material 1 by substituting the optimal solution x _opt,k,j (k = 1 to N, j = 1 to 7) of the operation ratio x _{k,j of the first to seventh temperature control devices 40, 51 to 56, the maximum temperature changeable amount ΔT k,j (} k = 1 to N, j = 1 to 7) of the first to seventh temperature control devices _{40, 51 to 56,} and the reference temperature T- _k into equation ⁽¹⁾ . The initial value T ⁽⁰⁾ _cal,k of the calculated value T _k of the finish rolling mill outlet temperature at the k-th control point of the rolled material 1 is the calculated value of the finish rolling mill outlet temperature at the k-th control point of the rolled material 1, which is achieved by operating each temperature control device 40, 51 to 56 with the initial value z ⁽⁰⁾ k _,j (j = 1 to 7) of the valve opening (operation amount) of each temperature control device 40, 51 to 56 for the k-th control point of the rolled material 1. The symbol z ⁽⁰⁾ _k,j corresponds to the symbol with (0) arranged above z and k and j arranged below it in each formula described later. The symbol T ⁽⁰⁾ _cal,k corresponds to the symbol with (0) arranged above T and cal and k arranged below it in each formula described later.

<<Output unit 832>>
The output unit 832 outputs the valve opening z _k,j (k=1 to N, j=1 to 7) of the j-th temperature control device for the k-th control point of the rolled material 1 calculated by the initial value calculation unit 831 to the j-th temperature control device. When the j-th temperature control device acquires tracking information from the tracking device 30 indicating that the k-th control point of the rolled material 1 has newly reached its own installation position, it changes its own valve opening to the valve opening z _k,j output from the output unit 832. At this time, feedback control by the FB control unit 840 described later is not executed until the first control point at the forefront of the rolled material 1 reaches the installation position of the finishing rolling mill delivery thermometer 70. Therefore, the valve openings z _k,j (k=1 to N, j=1 to 7) used in each of the temperature control devices 40, 51 to 56 are equal to the initial values z ⁽⁰⁾ _k,j (k=1 to N, j=1 to 7), i.e., the valve openings z _k,j (k=1 to N, j=1 to 7) output from the output unit 832. In addition, the output unit 832 outputs the various initial values calculated by the initial value calculation unit 831, the maximum temperature changeable amount ΔT _k,j (k=1 to N, j=1 to 7), and the reference temperature T- _k (k=1 to N) to the FB control unit 840. As mentioned above, the initial values calculated by the initial value calculation unit 831 are the initial value z ⁽⁰⁾ k, _j (k = 1 to N, j = 1 to 7) of the valve opening (operation amount) of each temperature control device 40, 51 to 56 for the kth control point of the rolled material 1, the initial value δ ( ⁰ ) of the correction amount δ of the finishing rolling mill outlet temperature, and the initial value T ⁽⁰⁾ _cal,k (k = 1 to N) of the calculated value T _k of the finishing rolling mill outlet temperature at the kth control point of the rolled material 1.

<FB control unit 840>
When the FB control unit 840 obtains the measured value θ _F,n of the finish rolling mill delivery temperature at the nth control point of the rolled material 1, the FB control unit 840 determines the valve openings (operation amounts) z k, _{j (j=1 to 7) of the first to seventh temperature control devices for the control point located on the rear end side (upstream side D1) of the rolled material 1 relative to the nth control point, that is, the kth control point satisfying k} >n. The FB control unit 840 executes such determination of the valve openings (operation amounts) every time it is determined that the nth control point (n=1 to N) of the rolled material 1 has newly reached the installation position of the finish rolling mill delivery thermometer 70 based on the tracking information output from the tracking device 30. Hereinafter, the detailed function of the FB control unit 840 will be described assuming that the nth control point of the rolled material 1 has newly reached the installation position of the finish rolling mill delivery thermometer 70. In this embodiment, the FB control unit 840 includes a temperature calculation unit 841 , a correction amount calculation unit 842 , a manipulated variable determination unit 843 , and an output unit 844 .

<<Temperature calculation unit 841>>
When the measured value of the finish rolling mill outlet temperature is obtained, the temperature calculation unit 841 calculates a calculated value of the finish rolling mill outlet temperature for the nth control point of the rolled material 1 based on the latest value z _n,j of the operation amount of the temperature control device for the nth control point of the rolled material 1. As described above, in this embodiment, a case is exemplified in which the processing device 80 determines the operation amount of each temperature control device 40, 51 to 56 for each control point of the rolled material 1. Therefore, when the measured value of the finish rolling mill outlet temperature at the nth control point of the rolled material 1 is obtained, the temperature calculation unit 841 calculates a calculated value of the finish rolling mill outlet temperature at the nth control point of the rolled material 1. An example of the detailed function of the temperature calculation unit 841 will be described below.

When the valve opening (operation amount) of each temperature control device 40, 51 to 56 for the nth control point of the rolled material 1 is the initial value z ⁽⁰⁾ _n,j (n = 1 to N, j = 1 to 7), the calculated value of the finish rolling mill outlet temperature at the nth control point of the rolled material 1 is T ⁽⁰⁾ _cal,n . However, when the measured values θ _F,1 to θ F,n-1 of the finish rolling mill outlet temperature at the 1st to n-1th control points on the tip side (downstream side _D2) of the nth control point of the rolled material 1 are obtained, the valve opening of each temperature control device 40, 51 to 56 for the nth control point of the rolled material 1 may have been updated by feedback control by the FB control unit 840 described below. Therefore, it is necessary to recalculate the calculated value of the finish rolling mill outlet temperature at the nth control point of the rolled material 1.

In this embodiment, a case will be illustrated in which the calculated value T _cal,n of the finish rolling mill delivery temperature at the nth control point of the rolled material 1 is calculated using an initial value T ⁽⁰⁾ _cal,n of the calculated value of the finish rolling mill delivery temperature at the nth control point of the rolled material 1, an initial value z ⁽⁰⁾ _n,j of the operation amount of each temperature control device for the nth control point of the rolled material 1, a maximum temperature changeable amount ΔT _n,j (j = 1 to 7), and the latest value z _n,j of the operation amount of the temperature control device for the nth control point of the rolled material 1. The symbol indicating the latest value of the valve opening (operation amount) of each temperature control device 40, 51 to 56 for the nth control point of the rolled material 1 will be denoted as z _n,j (n = 1 to N, j = 1 to 7). The operation ratio x n _{,j (n=1 to N, j=} 1 to 7) of each temperature control device 40, 51 to 56 for the nth control point of the rolled material 1 when the valve opening of each temperature control device 40, 51 to 56 for the nth control point of the rolled material 1 is the latest value z n,j is expressed by the following formula (7). Also, the operation ratio x ⁽⁰⁾ _{n ,j} (n=1 to N, j=1 to 7) of each temperature control device 40, 51 to 56 for the nth control point of the rolled material 1 when the valve opening of each temperature control device 40, 51 to 56 for the nth control point of the rolled material 1 is the initial value z ⁽⁰⁾ _n ,j is expressed by the following formula (8). Note that the symbol x ⁽⁰⁾ _n,j corresponds to the symbol in each formula where (0) is arranged above x and n and j are arranged below it.

Using x _n,j in equation (7) and x ⁽⁰⁾ _n,j in equation (8), from equation (1), the calculated value T _cal,n of the finish rolling mill delivery temperature for the nth control point of the rolled material 1 is expressed by the following equation (9).

The second term on the right side of equation (9) represents the change in the calculated value of the finishing rolling mill outlet temperature at the nth control point of the rolled material 1 relative to the initial value T (0 ⁾ _{cal ,n} when the operation ratio of each temperature control device 40, 51 to 56 for the nth control point of the rolled material 1 is changed from x ⁽⁰⁾ _{n,j to x n,j} .
The temperature calculation unit 841 calculates the operation ratio x _{n,j of each of the temperature control devices 40, 51 to 56 for the nth control point of the rolled material 1 when the valve opening of each of the temperature control devices 40, 51 to 56 for the nth control point of the rolled material 1 is the latest value z n ,} j by equation (7). The temperature calculation unit 841 also calculates the operation ratio x ^{(0) n,j of each of the temperature control devices 40, 51 to 56 for the nth control point of the rolled material 1 when the valve opening of each of the temperature control devices 40, 51 to 56 for the nth control point of the rolled material 1 is the initial value z (0) k} _{, j} by equation (8). Then, the temperature calculation unit 841 substitutes these calculated values (x _n,j , x ⁽⁰⁾ _n,j ) and the initial value T ⁽⁰⁾ _cal,n of the calculated value of the finish rolling mill delivery temperature at the nth control point of the rolled material 1 into equation (9). This allows the calculated value T _cal,n of the finish rolling mill delivery temperature at the nth control point of the rolled material 1 to be calculated.

<<Correction amount calculation unit 842>>
The correction amount calculation unit 842 calculates a correction amount of the finish rolling mill outlet temperature based on the measured value of the finish rolling mill outlet temperature and the calculated value of the finish rolling mill outlet temperature calculated by the temperature calculation unit 841. In this embodiment, the correction amount calculation unit 842 calculates a correction amount δ (n) of the finish rolling mill outlet temperature at the nth control point of the rolled material 1 based on the measured value θ _F,n of the finish rolling mill outlet temperature at the nth control point of the rolled material 1 and the calculated value T _cal,n of the finish rolling mill outlet temperature at the nth control point of the rolled material 1 calculated by the temperature calculation unit ⁸⁴¹ , and updates the correction amount of the finish rolling mill outlet temperature. The correction amount calculation unit 842 calculates the correction amount δ ⁽ⁿ⁾ of the finish rolling mill outlet temperature at the nth control point of the rolled material 1, for example, by the following formula (10).

Here, a is a smoothing gain for suppressing a large change in the correction amount δ ⁽ⁿ⁾ of the finish rolling mill delivery temperature at the nth control point of the rolled material 1 at once. A value greater than 0 and less than 1 (0<a<1) is set in advance as the value of the smoothing gain a.

<<Operation amount determination unit 843>>
The manipulated variable determiner 843 determines the manipulated variable of the temperature adjustment device for the rolled material 1 for which the measured value θ _F,n of the finish rolling mill delivery temperature has been acquired, based on the correction amount δ ⁽ⁿ⁾ of the finish rolling mill delivery temperature calculated and updated by the correction amount calculator 842. In this embodiment, the manipulated variable determiner 843 determines the manipulated variable of the temperature adjustment device for the kth control point (k = n + 1 to ^{N) located on the rear end side of the rolled material 1 relative to the nth control point, based on the correction amount δ (} n) of the finish rolling mill delivery temperature at the nth control point of the rolled material 1. An example of the detailed functions of the manipulated variable determiner 843 will be described below.
When the calculated value T _k of the finish rolling mill delivery temperature calculated by the formula (1) is corrected by using the correction amount δ ⁽ⁿ⁾ of the finish rolling mill delivery temperature shown in the formula (10), the finish rolling mill delivery temperature T _k at the kth control point (k = n + 1 to N) of the rolled material 1 is expressed by the following formula (11).

The manipulated variable determination unit 843 calculates the operation ratio x k,j of the jth temperature control device for the kth control point of the rolled material 1, which minimizes the value of the objective function J _k in equation (4) within a range satisfying the inequality constraint condition equations of equations (2) and (3), by solving an optimization problem by mathematical programming, using an optimal solution x _{opt,k,j (} k = n + 1 to N, j = 1 to 7) of the operation ratio x _k,j of the jth temperature control device for the kth control point of the rolled material 1. In the process in the initial value calculation unit 831, T _k expressed by equation (1) is used as T _k in equation (3). In contrast, in the process in the manipulated variable determination unit 843, T _k expressed by equation (11) is used as T _k in equation (3). In the process in the initial value calculation unit 831, the k of the calculation target of the optimal solution x _opt,k,j when the roughing mill exit temperature θ _R,k of the k-th control point is obtained is one of the control points k where the roughing mill exit temperature is measured. In contrast, in the process in the manipulated variable determination unit 843, the k of the calculation target of the optimal solution x _opt,k,j when the finishing mill exit temperature θ _F,n of the n-th control point is obtained is one of the control points n+1 to N located on the rear end side of the control point where the finishing mill exit temperature is measured. Note that, in the manipulated variable determination unit 843 as well, as described in the section <<Initial value calculation unit 831>>, the objective function J _k may be configured to solve a maximization problem instead of a minimization problem.

The manipulated variable determination unit 843 calculates and updates the valve openings z _k,j (k=n+1 to _{N, j=1 to 7) of the temperature control devices 40, 51 to 56 for the kth control point of the rolled material 1 by solving the following equation (12) using the optimal solution x opt,k,j} of the operation ratio x k _,j of each of the temperature control devices 40, 51 to 56 for the kth control point of the rolled material 1. In this manner, in this embodiment, the valve openings z _k,j of each of the temperature control devices 40, 51 to 56 when controlling the temperature of the kth control point of the rolled material 1 are calculated as the latest values of the manipulated variables.

<<Output unit 844>>
The output unit 844 outputs the valve opening z _k,j (k=n+1 to N, j=1 to 7) of the j-th temperature control device for the k-th control point of the rolled material 1 calculated and updated by the operation amount determination unit 843 to the j-th temperature control device. The j-th temperature control device replaces the valve opening z _k,j output from the output unit 832 of the FF control unit 830 (feedforward control) with the valve opening z _k,j output from the output unit 844 of the FB control unit 840 (feedback control), and when it acquires tracking information indicating that the k-th control point (k=n+1 to N) of the rolled material 1 has newly reached its own installation position from the tracking device 30, it changes the valve opening to that value. This realizes feedback control using the measured value θ _F,n of the finishing rolling mill exit temperature at the n-th control point of the rolled material 1.

<Flowchart>
Next, an example of the feedforward control process performed by the processing device 80 (FF control section 830) will be described with reference to the flowchart of FIG.
First, in step S401, the FF control unit 830 sets an initial value (=1) to a variable k (sampling number of the roughing mill delivery temperature) for identifying a control point of the rolled material 1.
Next, in step S402, the roughing mill delivery temperature acquisition unit 820 acquires the measured value θ _R,k of the roughing mill delivery temperature at the k-th control point of the rolled material 1.

Next, in step S403, the initial value calculation unit 831 calculates, as a reference temperature T _{-k, the finishing mill outlet temperature T-k of the rolling material 1 at the kth control point when the valve opening (operation amount) of each of the temperature control devices 40, 51 to 56 is set to 0 (zero) based on the measured value θ R, k} of the roughing mill outlet temperature of the rolling material 1 at the _kth control point.
Next, in step S404, the initial value calculation unit 831 calculates (predicts) the finish rolling mill delivery temperature at the kth control point of the rolled material 1 when the valve opening (operation amount) of any one of the temperature control devices 40 _, 51 to 56 is maximized and the remaining valve openings (operation amounts) are set to 0 (zero) based on the roughing mill delivery temperature θ R,k at the kth control point of the rolled material 1, individually for each of the temperature control devices 40, 51 to 56. Then, the initial value calculation unit 831 calculates a value obtained by subtracting the reference temperature T- _k from the calculated finish rolling mill delivery temperature at the kth control point as the maximum temperature changeable amount ΔT _k,j (j=1 to 7) of each of the temperature control devices 40, 51 to 56.

Next, in step S405, the initial value calculation unit 831 calculates the operation ratio x k,j of the j-th temperature control device for the k-th control point of the rolled material 1, which minimizes the value of the objective function J _k in equation (4), within the range satisfying the inequality constraint condition equations (2) and (3), as an optimal solution x _{opt,k,j (} j = 1 to 7) of the operation ratio x _k,j of the j-th temperature control device for the k-th control point of the rolled material 1.
Next, in step S406, the initial value calculation unit 831 calculates the valve opening degree z _k,1 of the coarse bar cooling device 40 for the k-th control point of the rolled material 1 by solving the equation (5) using the optimal solution x _opt,k,1 of the operation ratio x _k,1 of the coarse bar cooling device 40. Also, the initial value calculation unit 831 calculates the valve opening degree z _{k,i+1 (i = 1 to 6) of the cooling spray device 50 + i for the k-th control point of the rolled material 1 by solving the equation (6) using the optimal solution x opt,k,i + 1} of the operation ratio x _{k,i + 1} of the cooling spray device 50 + i. In this manner, the valve opening degree z k,j (j = 1 to 7) of the j-th temperature control device 40, 51 to 56 corresponding to the optimal solution x _{opt,k ,j} of the operation ratio x k, _j of the j-th temperature control device for the k-th control point of the rolled material 1 calculated in step S405 is calculated.

Next, in step S407, the output unit 832 outputs the valve openings z _k,j (j=1 to 7) of the j-th temperature controllers 40, 51 to 56 for the k-th control point of the rolled material 1 calculated in step S406 to the j-th temperature controller.
Next, in step S408, the initial value calculation unit 831 sets the valve opening z _k,j (j=1 to 7) of each temperature control device 40, 51 to 56 calculated in step S406 as the initial value z ⁽⁰⁾ _k, j (j=1 to 7) of the valve opening of each temperature control device 40, 51 to 56 for the kth control point. In addition, the initial value calculation unit 831 initializes the initial value δ ⁽⁰⁾ of the correction amount δ of the finishing rolling mill delivery temperature to 0 (zero) (δ ⁽⁰⁾ = 0).

Next, in step S409, the initial value calculation unit 831 substitutes the optimal solution x _opt,k,j (j = 1 to 7) of the operation ratio x _k,j of each temperature control device 40, 51 to 56 into equation (1) to calculate the initial value T ⁽⁰⁾ _cal,k of the calculated value T _k of the finishing rolling mill outlet temperature at the kth control point of the rolled material 1.

Next, in step 410, the output unit 832 outputs the initial values z ⁽⁰⁾ _k,j (k = 1 to N, j = 1 to 7), δ ⁽⁰⁾ , T ⁽⁰⁾ _cal,k (k = 1 to N) calculated by the initial value calculation unit 831, the maximum temperature change possible amount ΔT _k,j (k = 1 to N, j = 1 to 7), and the reference temperature T- _k (k = 1 to N) to the FB control unit 840.

Next, in step S411, the FF control unit 830 determines whether the variable k is N. If the result of this determination is that the variable k is not N (NO in step S411), the FF control unit 830 has not completed processing for all control points of the rolled material 1, and the process proceeds to step S412. In step S412, the FF control unit 830 adds 1 to the value of the variable k to update the variable k. Then, the processes of steps S402 to S411 are executed for the updated kth control point. Then, when it is determined in step S411 that the variable k is N (YES in step S411), the process according to the flowchart in FIG. 4 ends.

Next, an example of the feedback control process performed by the processing device 80 (FB control unit 840) will be described with reference to the flowchart of FIG.
First, in step S501, the FB control unit 840 sets an initial value (=1) to a variable n (sampling number of the finish rolling mill delivery temperature) for identifying a control point of the rolled material 1.
Next, in step S502, the FB control unit 840 acquires the initial values z ⁽⁰⁾ _k,j (k = 1 to N, j = 1 to 7), δ ^{(0), T (0 )} _cal,k (k = 1 to N), the maximum temperature changeable amount ΔT _k,j (k = 1 to N, j = 1 to 7), and the reference temperature T- _k (k = 1 to N) output from the FF control unit 830 in step S410 of FIG. 4.

Next, in step S503, the finishing rolling mill delivery temperature acquisition unit 810 acquires the measured value θ _F,n of the finishing rolling mill delivery temperature at the n-th control point of the rolled material 1.
Next, in step S504, the FB control unit 840 acquires the latest values z _n,j (j=1 to 7) of the valve openings (operation amounts) of the temperature control devices 40, 51 to 56 for the nth control point of the rolled material 1 from the temperature control devices 40, 51 to 56.

Next, in step S505, the temperature calculation unit 841 calculates the operation ratio x _{n,j (j = 1 to 7) of each temperature control device 40, 51 to 56 for the nth control point of the rolled material 1 when the valve opening of each temperature control device 40, 51 to 56 for the nth control point of the rolled material 1} is the latest value z _n,j using equation (7).
Next, in step S506, the temperature calculation unit 841 calculates the operation ratio x ⁽⁰⁾ _{n,j (j = 1} to 7) of each temperature control device 40, 51 to 56 for the nth control point of the rolled material 1 when the valve opening degree of each temperature control device 40, 51 to 56 for the nth control point of the rolled material 1 is the initial value z ⁽⁰⁾ _n,j using equation (8).

Next, in step S507, the temperature calculation unit 841 substitutes the values (x _n,j , x ⁽⁰⁾ _n,j ) calculated in steps S505 and S506, the initial value T ⁽⁰⁾ _cal,n of the calculated value of the finishing rolling mill outlet temperature at the nth control point of the rolled material 1 obtained in step S502, and the maximum temperature changeable amount ΔT _n,j (j = 1 to 7) into equation (9) to calculate the calculated value T _cal,n of the finishing rolling mill outlet temperature at the nth control point of the rolled material 1.
Next, in step S508, the correction amount calculation unit 842 calculates a correction amount δ (n) of the finish rolling mill delivery temperature at the nth control point of the rolled material 1 according to equation (10) using the measured value θ _F,n of the finish rolling mill delivery temperature at the nth control point of the rolled material 1 acquired in step S503 and the calculated value T _cal, ^{n of the finish rolling mill delivery temperature at the nth control point of the rolled material 1 calculated in step S507} .

Next, in step S509, the operation amount determination unit 843 calculates the operation ratio x k,j of the jth temperature control device for the kth control point of the rolled material 1, which is the minimum value of the objective function J _k in the equation (4) within the range satisfying the inequality constraint condition equations of the equations ( ₂₎ and (3), as the optimal solution x _opt,k,j (k = n + 1 to N, j = 1 to 7) of the operation ratio x _k,j of the jth temperature control device for the kth control point of the rolled material 1. Here, among the maximum temperature changeable amounts ΔT _k,j (k = 1 to N, j = 1 to 7) acquired in step S502, the maximum temperature changeable amounts ΔT _k, j of k = n + 1 to N, j = 1 to 7 are used. In addition, among the reference temperatures T- _k (k = 1 to N) acquired in step S502, the reference temperatures T- _k of k = n + 1 to N are used.
Next, in step S510, the operation amount determination unit 843 solves equation (12) using the optimal solution x _opt,k ,j of the operation ratio x _k,j of each temperature control device 40, 51 to 56 for the kth control point of the rolled material 1, to calculate and update the valve openings z k,j (k = n + 1 to N, j = 1 to 7) of the temperature control devices 40, 51 to 56 corresponding to the optimal solution x _{opt,k,j of} the operation ratio x k _,j of each temperature control device 40, 51 to 56 for the kth control point of the rolled material 1.

Next, in step S511, the output unit 844 outputs the valve opening z _k,j (k = n + 1 to N, j = 1 to 7) of the jth temperature control device for the kth control point of the rolled material 1 calculated in step S510 to each of the jth temperature control devices.
Next, in step S512, the FB control unit 840 judges whether the variable n is N or not. If the result of this judgment is that the variable n is not N (NO in step S512), the processing by the FB control unit 840 for all the control points of the rolled material 1 has not been completed, so the processing proceeds to step S513. In step S513, the FB control unit 840 adds 1 to the value of the variable n to update the variable n. Then, the processing of steps S502 to S512 is executed for the updated nth control point. Then, when it is judged in step S512 that the variable n is N (YES in step S512), the processing according to the flowchart of FIG. 5 ends.

<Summary>
As described above, in this embodiment, the processing device 80 calculates the correction amount δ (n) of the finish rolling mill delivery temperature based on the measured value θ _F,n of the finish rolling mill delivery temperature and the calculated value T _cal,n ^of the finish rolling mill delivery temperature, and determines the operation amount z k _,j of the temperature control devices 40, 51 to 56 so that the objective function of equation (4) is minimized based on the correction amount δ ⁽ⁿ⁾ of the finish rolling mill delivery temperature, as in the case of performing feedforward control. Therefore, this feedback control can be operated from the temperature control device located upstream. Also, unlike the method of feedback control based on the temperature deviation between the measured value and the target value of the finish rolling mill delivery temperature, feedback control can be performed without being affected by dead time. Therefore, when controlling the finish rolling mill delivery temperature, it is possible to achieve both suppression of shape deterioration of the rolled material and high response of temperature control.

In this embodiment, the processing device 80 calculates the calculated value T _cal,n of the finish rolling mill delivery temperature at the n-th control point where the measured value θ _R,n of the roughing mill delivery temperature is acquired based on the latest value z _n,j of the operation amount of the temperature control devices 40, 51 to 56, and calculates the correction amount δ ⁽ⁿ⁾ of the finish rolling mill delivery temperature. Then, the processing device 80 determines the operation amount z k,j of the temperature control devices 40, 51 to 56 so that the finish rolling mill delivery temperature T _k corrected by the correction amount δ ⁽ⁿ⁾ of the finish rolling mill delivery temperature satisfies a predetermined temperature condition (for example, d < T _k < u). Therefore, as the finish rolling mill delivery temperature that greatly affects the quality of the rolled material 1, the operation amount z _k,j of the temperature control devices 40, 51 to 56 can be determined using the finish rolling mill delivery temperature T _k corrected by the correction amount δ ⁽ⁿ⁾ _that reflects the state of the rolled material 1 downstream of the finish tandem rolling mill 20 as feedback.

In this embodiment, the processing device 80 calculates a correction amount δ (n) of the finish rolling mill outlet temperature at the n-th control point based on the measured value θ _F,n of the finish rolling mill outlet temperature at the n-th control point and the calculated value T _cal, ^{n of the finish rolling mill outlet temperature at the n-th} control point. Then, the processing device 80 determines the operation amount z k,j of the temperature control device for the k-th control point (k = n + 1 to N) located on the rear end side of the n-th control point based on the correction amount δ ⁽ⁿ⁾ of the finish rolling mill outlet temperature at the _n-th control point. Therefore, the finish rolling mill outlet temperature can be controlled for each control point. Therefore, depending on the setting interval of the control points, it is possible to prioritize reduction of the calculation load or execution of high-precision control.

In addition, in this embodiment, based on the measured value θ _R,k of the roughing mill exit temperature at the kth control point of the rolled material 1, the processing device 80 calculates an initial value z ⁽⁰⁾ _k,j (j = 1 to 7) of the operation amount of the temperature control devices 40, 51 to 56 for the kth control point, and an initial value T ⁽⁰⁾ _cal,k of the calculated value of the finishing rolling mill exit temperature at the kth control point achieved by manipulating the initial value. Then, when the processing device 80 obtains the measured value θ _F,n of the finish rolling mill delivery temperature at the nth control point of the rolled material 1, it calculates the calculated value T cal,n of the finish rolling mill delivery temperature at the nth control point using the initial value T ⁽⁰⁾ _cal,n of the calculated value of the finish rolling mill delivery temperature at the nth control point, the initial values z ⁽⁰⁾ _n,j of the operation amounts of the temperature control devices 40, 51 to 56 for the nth control point, and the latest values z _n,j of the operation amounts of the temperature control devices 40, 51 to ₅₆ for the nth control point. Therefore, it is only necessary to calculate the correction amount for the initial value z ⁽⁰⁾ _n,j of the operation amount of the temperature control devices 40, 51 to 56 for the nth control point, and the load of the prediction calculation of the finish rolling mill delivery temperature can be reduced.

As described above, the feedback control executed by the FB control unit 840 in this embodiment does not correct the operation amount of the temperature adjustment devices 40, 51 to 56 based on the deviation between the measured value and the target value of the finish rolling mill delivery temperature as in the techniques disclosed in Patent Documents 2 and 3, but calculates and updates (from δ (n-1)) the correction amount δ (n) of the finish rolling mill delivery temperature based on the measured value θ _F,n of the finish rolling mill delivery temperature at the nth control point reached at the installation position of the finish rolling mill delivery thermometer 70 and the calculated value T _cal, ⁿ of the finish rolling mill delivery temperature expressed by equation ( ⁹ ), and uses the correction amount δ ⁽ⁿ⁾ of the finish rolling mill delivery temperature to determine the operation amount of each temperature adjustment device 40, 51 to 56 for each control point located on the rear end side of the rolled material 1 from the nth control point. The essential difference between the feedforward control and the method of determining the manipulated variable of each temperature control device 40, 51 to 56 is that T _k in equation (1) in the feedforward control is corrected to match the measured value θ _F,n of the finish rolling mill outlet temperature by the correction amount δ ⁽ⁿ⁾ of the finish rolling mill outlet temperature in the feedback control as in equation (11). In addition, the method of determining the manipulated variable of the temperature control devices 40, 51 to 56 in the feedback control is the same as that in the feedforward control (see equations (2) to (4)). Therefore, in the feedback control in this embodiment, as in the conventional feedforward control, the temperature control device can be used from the upstream side, so that the deterioration of the shape of the rolled material 1 can be suppressed. In addition, the method of this embodiment is not a method of feedback control based on the deviation between the measured value and the target value, as in the methods disclosed in Patent Documents 2 and 3, so that the feedback control can be performed without being affected by dead time, and high response of the temperature control is possible. In addition, when the finishing mill outlet temperature is controlled to be equal to or higher than the lower limit temperature and equal to or lower than the upper limit temperature, if the feedback control described in Patent Documents 2 and 3 is applied, the temperature deviation is obtained with the lower limit temperature and the upper limit temperature as the dead zone. Therefore, the operation amount of the temperature adjustment devices 40, 51 to 56 is not changed until the measured value θ _F,n of the finishing mill outlet temperature deviates from the upper and lower limit temperatures, which causes a problem of slow response. In contrast, in the method of the present embodiment, even when the finishing tandem rolling mill outlet temperature is controlled to be equal to or higher than the lower limit temperature and equal to or lower than the upper limit temperature (see formula (3)), the correction amount δ ⁽ⁿ⁾ of the finishing mill outlet temperature is calculated and updated without making the lower limit temperature and the upper limit temperature the dead zone. Therefore, even if the measured value θ _F,n of the finishing mill outlet temperature does not deviate from the upper and lower limit temperatures, the operation amount of the temperature adjustment devices 40, 51 to 56 can be changed.

<Modification>
In this embodiment, in the feedback control by the FB control unit 840, an optimal solution x _{opt,k, j of the operation ratio x k,} j of all the temperature control devices 40, 51 to 56 is calculated, and the valve opening z _k,j of all the temperature control devices 40, 51 to 56 is changed to a value corresponding to the optimal solution x _opt,k,j . However, even if the operation amount of the temperature control device that has already passed the kth control point of the rolled material 1 among the temperature control devices 40, 51 to 56 is changed, the temperature of the kth control point cannot be changed. Therefore, it is preferable to change only the operation amount of the temperature control device that has not yet passed the kth control point. In this case, for example, the following may be performed. In this embodiment, the processing device 80 is provided with tracking information indicating the position of each control point of the rolled material 1 from the tracking device 30. Therefore, the operation amount determination unit 843 identifies a temperature control device that is downstream D2 (the tip side of the rolled material 1) of the position where the kth control point exists based on the tracking information. The manipulated variable determination unit 843 calculates a subscript m(k) corresponding to j in the manipulated variable ratio x _k,j corresponding to the manipulated variable of the temperature control device located at the most upstream position (the rearmost side of the rolled material 1). In this embodiment, when the temperature control device located at the most upstream position is the first temperature control device (coarse bar cooling device 40), m(k)=1, and when the temperature control device located at the most upstream position is the i+1 temperature control device (cooling spray device 50+i, i=1 to 6), m(k)=i+1. When m(k) is used, formula (11) is expressed as the following formula (13).

In equation (13), x _k,j (k=n+1 to N, j=1 to m(k)-1) is the operation ratio of a temperature control device (a temperature control device through which the kth control point of the rolled material 1 has already passed) located on the upstream side D1 of the position where the kth control point of the rolled material 1 exists. The operation amount determination unit 843 does not update the valve opening (operation amount) z _k,j (k=n+1 to N, j=1 to m(k)-1) of a temperature control device located on the upstream side D1 of the position where the kth control point of the rolled material 1 exists. Therefore, the manipulated variable determination unit 843 recalculates the manipulated variable x _k,j (k=n+1 to N, j=1 to m(k)-1) of the temperature control device located upstream D1 of the position where the kth control point of the rolled material 1 is located, using the latest value z _k,j (k=n+1 to N, j=1 to m(k)-1) of the valve opening (manipulated variable) of the temperature control device by the following formula (14). On the other hand, x _k,j (k=n+1 to N, j=m(k) to 7) is the manipulated variable of the temperature control device located downstream D2 of the position where the kth control point of the rolled material 1 is located (a temperature control device that has not yet passed the kth control point of the rolled material 1). The manipulated variable determination unit 843 calculates an optimal solution x _opt,k,j (k = n + 1 to N, j = m(k) to 7) of the operation ratio x _k,j of the temperature adjustment device located downstream of the position where the kth control point of the rolled material 1 exists, by solving an optimization problem by mathematical programming. At that time, the manipulated variable determination unit 843 fixes the operation ratio x _k,j (k = n + 1 to N, j = 1 to m(k) - 1) of the temperature adjustment device located upstream of the position where the kth control point of the rolled material 1 exists to a value calculated by the following formula (14) and treats it as a constant. In addition, as the inequality constraint condition formula, formula (2) and the following formula (15) are used instead of formula (2) and formula (3). Then, the manipulated variable determination unit 843 calculates and updates the valve openings z _k,j (k=n+1 to N, j=m(k) to 7) of the temperature control devices 40, 51 to 56 for the kth control point of the rolled material 1 by solving the following equation (16) using the optimal solution x _opt,k,j of the operation ratio x _k,j of the temperature control device located downstream D2 of the position where the kth control point of the rolled material 1 is located. Note that, when the kth control point of the rolled material 1 passes through the installation positions of all the temperature control devices 40, 51 to 56 (when it is located downstream D2 of all the temperature control devices 40, 51 to 56), m(k) cannot be obtained. In this case, the manipulated variable determination unit 843 does not update the valve openings z _k,j (k=n+1 to N, j=1 to 7) of the temperature control devices 40, 51 to 56 for the kth control point.

In this way, the processing device 80 identifies a temperature control device downstream of the control point at which the measured value θ _F,n of the finish rolling mill outlet temperature is obtained for each control point located at the rear end of the rolled material 1, and updates only the operation amount of the temperature control device downstream of the control point, thereby making it possible to update the operation amount of only the temperature control device that affects the finish rolling mill outlet temperature at the control point. This makes it possible to improve the performance of the feedback control of the finish rolling mill outlet temperature (for example, shortening the time until the finish rolling mill outlet temperature reaches a steady state and/or making the finish rolling mill outlet temperature approach a target value).

In this embodiment, in order to reduce the calculation load, the FB control unit 840 (temperature calculation unit 841) calculates the calculated value T _cal,n of the finishing rolling mill outlet temperature using the initial value T ⁽⁰⁾ cal,n of the calculated value of the finishing rolling mill outlet temperature calculated by the FF control unit 830, the initial values z ⁽⁰⁾ _n,j of the manipulated variables of each temperature control device, and the maximum temperature changeable amount ΔT _{n,j (} j = 1 to 7). However, the FB control unit 840 (temperature calculation unit 841) may also acquire the roughing rolling mill outlet temperature θ _R,n at the nth control point of the rolled material 1 and calculate the calculated value T _cal,n of the finishing rolling mill outlet temperature at the nth control point of the rolled material 1.

<Example>
EXAMPLES Next, examples will be described. Below, the present invention will be described in more detail by specifically showing examples and comparative examples, but the present invention is not limited to the following examples.
In this example, the results of computer simulation using the method described in this embodiment will be described. In both the invention example and the comparative example, the lower limit temperature d of the finishing mill outlet temperature was set to 860 ° C., and the upper limit temperature u was set to 900 ° C. In addition, the sampling pitch of the rough rolling mill outlet temperature of the rough bar was set to 0.5 m, and the rough rolling mill outlet temperature of each sampled control point was set to the rough rolling mill outlet temperature shown in FIG. 6. The distance from the rough bar tip on the horizontal axis of FIG. 6 represents the distance from the tip of the rolled material 1 in the state of the rough bar to each control point. In addition, in order to show the difference due to the presence or absence of feedback control, the measured value θ _R,k of the rough rolling mill outlet temperature of each control point was set to be 10 ° C. higher than the temperature calculated by computer simulation.

Figures 7, 8, and 9 show the simulation conditions and results for Comparative Example 1, Comparative Example 2, and an example of the invention, respectively. The finishing rolling speed on the vertical axis in (a) of Figures 7 to 9 represents the rolling speed (circumferential speed of the rolling rolls of rolling stand F7) of the finishing tandem mill 20 when each control point passes through rolling stand F7. As shown in (a) of Figures 7 to 9, the finishing rolling speed accelerates midway through rolling and then becomes constant. The valve openings in (c) to (i) of Figures 7 to 9 are expressed as relative values, with 1 being fully open and 0 (zero) being fully closed. In addition, the F1 outlet spray device, F2 outlet spray device, F3 outlet spray device, F4 outlet spray device, F5 outlet spray device, and F6 outlet spray device on the vertical axes of (d), (e), (f), (g), (h), and (i) in Figures 7 to 9 represent cooling spray devices 51, 52, 53, 54, 55, and 56, respectively.

In Comparative Example 1, which is an example of a conventional method, as in Patent Document 2, the feedforward operation amount of the temperature control device at each control point is calculated based on the measured value of the roughing mill exit temperature at each control point. Then, after the finishing mill exit temperature is measured, the temperature deviation between the measured value of the finishing mill exit temperature and the target value is integrated to calculate the feedback operation amount of the temperature control device, giving priority to the temperature control device located downstream, and the feedforward operation amount and the feedback operation amount are added together to obtain the operation amount of the temperature control device. The results of the computer simulation of Comparative Example 1 are shown in Figure 7 (b) to (i).

In Comparative Example 2, which is another example of the conventional method, as in Patent Document 3, the initial operation amount of the temperature control device is determined as a feedforward operation amount so that the temperature control device located upstream is used preferentially based on the measured value of the roughing mill exit temperature until the finishing rolling mill exit temperature is measured. Then, when the finishing rolling mill exit temperature is measured, the feedforward operation amount is fixed to the value at that time. After the finishing rolling mill exit temperature is measured, the temperature deviation between the measured value of the finishing rolling mill exit temperature and the target value is integrated, and the operation amount of the temperature control device located most downstream among the temperature control devices outputting an operation amount other than 0 (zero) is added as a feedback operation amount to the feedforward operation amount fixed as described above to correct the operation amount of the temperature control device. The results of the computer simulation of Comparative Example 2 are shown in (b) to (i) of Figure 8.

In the example of the invention, as described in the present embodiment, the initial value of the operation amount of the temperature control device for each control point is determined as a feedforward operation amount based on the measured value of the roughing mill exit temperature at each control point. Then, after the finishing mill exit temperature is measured, the correction amount of the finishing mill exit temperature is calculated based on the measured value of the finishing mill exit temperature and the calculated value of the finishing mill exit temperature, and the operation amount of each temperature control device is replaced with the feedforward operation amount as a feedback operation amount based on the calculated correction amount of the finishing mill exit temperature. The results of the computer simulation of the example of the invention are shown in (b) to (i) of FIG.
7 to 9, the dotted lines show the case where the manipulated variable of the temperature control device using the measured value of the finish rolling mill delivery temperature (i.e., addition of the feedback manipulated variable) is not performed, and the solid lines show the case where it is performed. The time on the horizontal axis is the time when the tip of the rolled material 1 reaches the installation position of the coarse bar cooling device 40, which is set to 0 (zero).

In Comparative Example 1, as shown in FIG. 7, after 36.7 s when the measured value of the finishing mill exit temperature (b) exceeded the upper limit temperature of 900°C, the valve opening was changed in the opening direction to the F6 exit spray device (i), the F5 exit spray device (h), and the F4 exit spray device (g) (in the order of cooling spray devices 56, 55, and 54). As a result, the measured value of the finishing mill exit temperature (b) was changed to within the range of 860 to 900°C, which is the upper and lower limit temperature range, at approximately 52.8 s. However, with this method, the amount of operation of the downstream cooling spray device is greatly modified, so there is a high possibility that the shape of the rolled material 1 will deteriorate. In addition, the tip of the rolled material 1 reaches the installation position of the finishing mill exit thermometer 70 and measurement of the finishing mill exit temperature begins at 22.3 seconds, but there is a problem in that the operation amount (valve opening) of the coarse bar cooling device 40 and the operation amount (valve opening of the cooling spray devices 51-56) (valve opening of the F1-F6 exit spray devices) are not changed until 36.7 seconds when the measured value of the finishing mill exit temperature exceeds the upper limit temperature of 900°C.

In Comparative Example 2, as shown in FIG. 8, after 36.7 s (point A) when the measured value of the finishing mill exit temperature (b) exceeded the upper limit temperature of 900°C, the valve opening was changed in the opening direction in the order of the rough bar cooling device (c), the F1 exit spray device (d), the F2 exit spray device (e), the F3 exit spray device (f), the F4 exit spray device (g), and the F5 exit spray device (h) (in the order of the rough bar cooling device 40, the cooling spray devices 51, 52, 53, 54, and 55), so that the measured value of the finishing mill exit temperature (b) was corrected to the upper and lower limit temperature range of 860 to 900°C at about 59.9 s. However, with this method, the dead time from when the upstream cooling adjustment device, which is the subject of the change in the manipulated variable at the beginning of feedback control, is operated until the result appears in the measured value of the finishing mill exit temperature is very large. Specifically, the control point (see point A) where temperature control is first performed at the point 36.7 s (point A) when the measured value of the finish rolling mill outlet temperature in (b) exceeds the upper limit temperature of 900°C, takes as long as 15.3 s until it moves to the installation position of the finish rolling mill outlet thermometer 70 and appears as the measured value of the finish rolling mill outlet temperature in (b) (see point B) (this 15.3 s period is the period from point A to point B). For this reason, not only is the time required for the measured value of the finish rolling mill outlet temperature in (b) to reach the upper and lower limit temperature range of 860 to 900°C longer than in Comparative Example 1, but thereafter a large temperature drop occurs. Also, as with Comparative Example 1, there is a problem in that the operation amount (valve opening) of the coarse bar cooling device 40 and the operation amount (valve opening of the F1 to F6 exit spray devices in (d) to (i) of Figure 8) are not changed until 36.7 s when the measured temperature of the exit side of the finishing rolling mill exceeds the upper limit temperature of 900°C.

In contrast to Comparative Examples 1 and 2, in the Example of the Invention, as shown in FIG. 9, after 22.3 s when measurement of the finishing mill exit temperature begins, the valve opening is changed to the open direction, with priority given to the temperature control device located upstream of each control point. Therefore, the measured value of the finishing mill exit temperature in FIG. 9(b) falls within the upper and lower limit temperature range of 860 to 900°C over the entire length of the rolled material 1. Note that in Comparative Example 2, in order to more clearly show the differences from the Example of the Invention, a case in which the feedforward operation amount is fixed is illustrated, unlike Comparative Example 1 and the Example of the Invention, but the fact that the dead time is longer in Comparative Example 2 does not change depending on the form of feedforward control.

In this way, in the example of the invention, by giving priority to correcting the operation amount of the temperature adjustment device located upstream, it is possible to suppress deterioration of the shape of the rolled material. Furthermore, feedback control can be executed without being affected by dead time. Also, when the finishing rolling mill outlet temperature is set within the range of upper and lower limit temperatures, even if the measured value of the finishing rolling mill outlet temperature is above the lower limit temperature and below the upper limit temperature, the correction amount for the finishing rolling mill outlet temperature is calculated and the operation amount of the temperature adjustment device is re-determined, thereby enabling high responsiveness of temperature control.

The above-described embodiment of the present invention can be realized by a computer executing a program. A computer-readable recording medium on which the program is recorded and a computer program product such as the program can also be applied as an embodiment of the present invention. Examples of the recording medium that can be used include a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a magnetic tape, a non-volatile memory card, and a ROM.
Furthermore, the above-described embodiments of the present invention are merely examples of the implementation of the present invention, and the technical scope of the present invention should not be interpreted as being limited by these. In other words, the present invention can be implemented in various forms without departing from its technical concept or main features.

LIST OF SYMBOLS 1 Rolled material 10 Roughing mill 20 Finishing tandem rolling mill 30 Tracking device 40 Rough bar cooling device 51-56 Cooling spray device 60 Roughing mill exit thermometer 70 Finishing mill exit thermometer 80 Processing device 100 Rolling equipment 810 Finishing mill exit temperature acquisition unit 820 Roughing mill exit temperature acquisition unit 830 FF control unit 831 Initial value calculation unit 832 Output unit 840 FB control unit 841 Temperature calculation unit 842 Correction amount calculation unit 843 Operation amount determination unit 844 Output unit D1 Upstream side D2 Downstream side F1-F7 Rolling stand R Conveyor path

Claims (6)

A processing device that determines an operation amount of a temperature control device that adjusts the temperature of a rolled material being transported between the exit side of a roughing mill and the exit side of a finishing rolling mill,
A finishing mill outlet temperature acquisition means for acquiring a measured value of a finishing mill outlet temperature, which is the temperature of the rolled material at the outlet of the finishing mill;
a temperature calculation means for calculating a calculation value of the finish rolling mill delivery temperature based on the latest value of the operation amount of the temperature control device;
a correction amount calculation means for calculating a correction amount of the finishing rolling mill delivery temperature based on the measured value of the finishing rolling mill delivery temperature acquired by the finishing rolling mill delivery temperature acquisition means and the calculated value of the finishing rolling mill delivery temperature calculated by the temperature calculation means;
an operation amount determining means for determining an operation amount of the temperature control device for the rolled material for which the measured value of the finish rolling mill delivery temperature has been acquired based on the correction amount of the finish rolling mill delivery temperature;
Equipped with
A plurality of control points are set for the rolled material at intervals in a conveying direction of the rolled material,
the temperature calculation means calculates a calculated value of the finish rolling mill delivery temperature at one of the control points when a measured value of the finish rolling mill delivery temperature at the control point is acquired,
the correction amount calculation means calculates a correction amount of the finish rolling mill delivery temperature at the control point based on a measured value of the finish rolling mill delivery temperature at the control point and a calculated value of the finish rolling mill delivery temperature at the control point;
the operation amount determination means determines operation amounts of the temperature control devices for all of the control points located on the rear end side of the control point that is present at the measurement position of the finish rolling mill delivery temperature based on a correction amount of the finish rolling mill delivery temperature at the control point,
The operation amount determination means is a processing device that identifies a temperature control device that is downstream of the position where the control point is located for all of the control points located downstream of the control point that is located at the measurement position of the exit temperature of the finishing rolling mill, and updates only the operation amount of the temperature control device that is downstream of the position where the control point is located . A roughing mill outlet temperature acquisition means for acquiring a measured value of a roughing mill outlet temperature, which is the temperature of the rolled material at the outlet of the roughing mill;
Further comprising:
The temperature calculation means calculates a calculation value of the finishing rolling mill outlet temperature at a position of the rolling material where the measurement value of the roughing rolling mill outlet temperature is acquired by the roughing rolling mill outlet temperature acquisition means, based on the latest value of the operation amount of the temperature control device;
2. The processing apparatus according to claim 1, wherein the manipulated variable determination means determines the manipulated variable of the temperature adjustment device so that the finish rolling mill delivery temperature corrected by the correction amount of the finish rolling mill delivery temperature satisfies a predetermined temperature condition. The method further includes an initial value calculation means for calculating an initial value of an operation amount of the temperature control device for the control point based on a measured value of a roughing mill delivery temperature, which is the temperature of the rolled material at the delivery side of the roughing mill, and an initial value of a calculated value of the finishing rolling mill delivery temperature at the control point achieved by operating the initial value,
3. The processing device according to claim 1, wherein, when a measured value of the finish rolling mill outlet temperature at the control point is obtained, the temperature calculation means calculates a calculated value of the finish rolling mill outlet temperature at the control point using an initial value of the calculated value of the finish rolling mill outlet temperature at the control point, an initial value of the operation amount of the temperature control device for the control point, and a latest value of the operation amount of the temperature control device for the control point. The processing device according to any one of claims 1 to 3, wherein the operation amount determination means determines the operation amount of the temperature adjustment device so that the finish rolling mill delivery temperature corrected by the correction amount of the finish rolling mill delivery temperature becomes equal to or higher than a preset lower limit temperature and equal to or lower than an upper limit temperature. A processing method for determining an operation amount of a temperature control device that controls a temperature of a rolled material being transported between an exit side of a roughing mill and an exit side of a finishing mill, comprising:
a finishing rolling mill delivery temperature acquisition step of acquiring a measured value of a finishing rolling mill delivery temperature, which is the temperature of the rolled material at the delivery side of the finishing rolling mill;
a temperature calculation step of calculating a calculation value of the finish rolling mill delivery temperature based on the latest value of the operation amount of the temperature control device;
a correction amount calculation step of calculating a correction amount of the finishing rolling mill delivery temperature based on the measured value of the finishing rolling mill delivery temperature acquired in the finishing rolling mill delivery temperature acquisition step and the calculated value of the finishing rolling mill delivery temperature calculated in the temperature calculation step;
an operation amount determination process for determining an operation amount of the temperature control device for the rolled material for which the measured value of the finish rolling mill delivery temperature has been acquired based on the correction amount of the finish rolling mill delivery temperature;
Equipped with
A plurality of control points are set for the rolled material at intervals in a conveying direction of the rolled material,
In the temperature calculation step, when a measured value of a finish rolling mill delivery temperature at one of the control points is acquired, a calculated value of the finish rolling mill delivery temperature at the control point is calculated,
In the correction amount calculation step, a correction amount of the finish rolling mill delivery temperature at the control point is calculated based on a measured value of the finish rolling mill delivery temperature at the control point and a calculated value of the finish rolling mill delivery temperature at the control point,
In the operation amount determination step, an operation amount of the temperature control device is determined for all of the control points located on the rear end side of the control point that is located at a measurement position of the finish rolling mill delivery temperature based on a correction amount of the finish rolling mill delivery temperature at the control point,
In the operation amount determination step, for all of the control points located downstream of the control point at the measurement position of the finishing rolling mill outlet temperature, a temperature control device located downstream of the control point is identified, and only the operation amount of the temperature control device located downstream of the control point is updated . A program for causing each of the means to function as the processing device according to any one of claims 1 to 4 .