1. A rolling control device which controls a rolling mill (1, S 100) for rolling a material (u) to be rolled by a pair of rolls (Rsl, Rs2), comprising: a roll gap control part (7) to control space between the rolls (Rsl, Rs2) in the pair of rolls on basis of tension of the material (u) inserted into the rolling mill to be rolled by the rolling mill or the material (u) sent out fkom the rolling mill after rolled; and a speed control part (4) to control carrying speed of the material (u) inserted into the rolling mill to be rolled by the rolling mill or the material (u) sent out from the rolling mill after rolled on basis of thickness of the rolled material (u).

2. A rolling control device according to Claim 1, wherein the roll gap control part (7) is configured to implement hnction of controlling the space between the rolls (Rsl, Rs2) in the pair of rolls on basis of the thickness of the rolled material (u) and the speed control part (4) is configured to implement hnction of controlling the carrying speed of the material (u) inserted into the rolling mill to be rolled by the rolling mill or the material (u) sent out from the rolling mill after rolled on basis of the tension of the material (u) inserted into the rolling mill to be rolled by the rolling mill or the material (u) sent out from the rolling mill after rolled, and the rolling control device comprises a control mode decision part (71) to decide execution modes of control based on the thickness of the rolled material (u) and control based on the tension of the material (u) performed by the roll gap control part (7) and the speed control part (4), respectively.

3. A rolling control device according to Claim 2, wherein I the control mode decision part (71) decides a rate of influencing the control based I I on the thickness of the rolled material (u) and a rate of influencing the control based on the I I tension of the material (u) performed by the roll gap control part (7) and the speed control part (4), respectively, and performs the control based on the thickness of the rolled material (u) and the control based on the tension of the material (u) in accordance with the decided rates.

4. A rolling control device according to Claim 1, hrther comprising: a roll gap adjustment interference prediction part which predicts influence on the thickness of the material (u) by a control output of the space between the rolls (Rsl, Rs2) by the ! roll gap control part (7) to supply prediction result to the speed control part (4); and a speed adjustment interference prediction part which predicts influence on the tension of the material (u) by a control output of the carrying speed of the material (u) by the - speed control part (4) to supply prediction result to the roll gap control part (7), and wherein the roll gap control part (7) controls the space between the rolls (Rsl, Rs2) in the pair of rolls on basis of the tension of the material (u) and the prediction result of the influence on the tension of the material (u) by the control output of the carrying speed of the material (u), and the speed control part (4) controls the carrying speed of the material (u) on the basis of the thickness of the rolled material (u) and the prediction result of the influence on the thickness of the material (u) by the control output of the space between the rolls (Rsl, Rs2).

5. A rolling control device according to Claim 3, hrther comprising: a roll gap adjustment interference prediction part which predicts influence on the thickness of the material (u) by a control output of the space between the rolls (Rsl, Rs2) by the roll gap control part (7) to supply prediction result to the speed control part (4); and a speed adjustment interference prediction part which predicts influence on the tension of the material (u) by a control output of the carrying speed of the material (u) by the speed control part (4) to supply prediction result to the roll gap control part (7), and wherein the roll gap control part (7) controls the space between the rolls (Rsl, Rs2) in the pair of rolls on basis of the tension of the material (u) and the prediction result of the influence on the tension of the material (u) by the control output of the carrying speed of the material (u), and the speed control part (4) controls the carrying speed of the material (u) on the basis of the thickness of the rolled material (u) and the prediction result of the influence on the thickness of the material (u) by the control output of the space between the rolls (Rsl, Rs2), the roll gap adjustment interference prediction part and the speed adjustment interference prediction part produce the prediction results when the decided rates fall within a predetermined range.

6. A rolling control device according to Claim 2, hrther comprising a tension reel torque control part (66) which controls torque of a tension reel for feeding the material (u) inserted into the rolling mill to be rolled by the rolling mill or a tension reel for winding the material (u) sent out from the rolling mill after rolled, and wherein the control mode decision part (71) decides the execution modes for the control performed by the roll gap control part (7) and the speed control part (4) and the control performed by the tension reel torque control part (66).

7. A rolling control device according to Claim 2 or 6, wherein the control mode decision part (71) decides the execution modes of the control on e - 26 - basis of variation of a rolling state when the space between the rolls (Rsl, Rs2) is changed stepwise during rolling.

8. A rolling control device according to Claim 1, wherein the roll gap control part (7) presumes the tension of the material (u) on basis of difference between a command value of electric power supplied to a tension reel for feeding the material (u) inserted into the rolling mill to be rolled by the rolling mill or a tension reel for winding the material (u) sent out from the rolling mill after rolled and an actual value of electric power supplied actually.

9. A rolling control method of controlling a rolling mill (1, S 100) for rolling a material (u) to be rolled by a pair of rolls (Rsl, Rs2), comprising: controlling space between the rolls (Rsl , Rs2) in the pair of rolls on basis of tension of the material (u) inserted into the rolling mill to be rolled by the rolling mill or the material (u) sent out from the rolling mill after rolled; and controlling carrying speed of the material (u) inserted into the rolling mill to be rolled by the rolling mill or the material (u) sent out from the rolling mill after rolled on basis of thickness of the rolled material (u).

10. A rolling control program of controlling a rolling mill (1, S 100) for rolling a material (u) to be rolled by a pair of rolls (Rsl, Rs2) by causing an information processing unit to execute the following steps of: controlling space between the rolls (Rsl, Rs2) in the pair of rolls on basis of tension of the material (u) inserted into the rolling mill to be rolled by the rolling mill or the material (u) sent out from the rolling mill after rolled; and controlling carrying speed of the material (u) inserted into the rolling mill to be rolled by the rolling mill or the material (u) sent out from the rolling mill after rolled on basis of thickness of the rolled material (u).

11. A rolling control device, substantially as herein described with reference to accompanying drawings and examples.

12. A rolling control method, substantially as herein described with reference to accompanying drawings and examples. Dated this 29th day of November 2013 Agent for the Applicant

BACKGROUND OF THE INVENTION
The present invention relates to a rolling control device, a rolling control method
and a rolling control program and, more particularly, to selection of operation ends and feedback
of a rolling mill having plural operation ends and feedback.
5 In a rolling mill using tension reels for feeding and winding a material to be
rolled, the tension reels are operated at fixed torque control (at fixed current control). When the
tension reels are operated at the fixed torque control, there arises a problem that when tension on
inlet and outlet sides of the rolling mill is varied, speed of the tension reels is changed in order to
suppress the variation, so that plate speed on the inlet side of the rolling mill is changed to
10 thereby vary plate thickness on the outlet side of the rolling mill. As a countermeasure thereof,
variation of the tension within a fixed range is allowed in order to operate the tension reels to be
controlled at fixed speed to thereby suppress the variation in the plate thickness on the outlet side
in the tension control in which the tension reel speed is used as an operation end (for example,
refer to JP-A-20 10-240662).
15 Further, in a tandem rolling mill, when an influence coefficient of a rolling mill is
changed greatly depending on the operation state, a control operation end to a control state
amount is changed properly (for example, refer to JP-A-20 12- 176428). In the tandem rolling
mill, usually, inter-stand tension control in which a rear-stage stand roll gap is used as a control
operation end and outlet-side plate thickness control in which front-stage stand speed is used as
20 the control operation end are performed. In contrast, the invention of JP-A-20 12- 176428
discloses that the outlet-side plate thickness control in which the rear-side stand roll gap is used
as the control operation end and tension control in which the front-stage stand speed is used as
the control operation end are performed, so that effects of the plate thickness control and the
tension control can be obtained at the maximum.
25
SUMMARY OF THE INVENTION
The fixed torque control operation of the feeding-side tension reel and the
winding-side tension reel causes variation in speed on the inlet and outlet sides of the rolling mill
to vary the plate thickness on the outlet side of the rolling mill. This reason is that when the
30 fixed torque control is performed, the speed of the tension reels is changed by the inertia of the
tension reels in order to control the torque of the tension reels to be fixed. Consequently, the
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plate thickness on the outlet side is varied by the constant mass-flow rule.
The accuracy of the plate thickness on the outlet side of the rolling mill is most
important for the material to be rolled produced by the rolling mill and the tension on the inlet
and outlet sides of the rolling mill is important for stability of operation, although even if the
5 tension may be changed slightly, there is no problem in rolling operation as far as the plate
thickness of products is maintained. On the basis of this thought, in the invention disclosed in
JP-A-2010-240662, priority is given to the fact that the speed of the tension reels is fixed with
respect to deviation from a set value of tension within a predetermined range and variation in the
speed of the tension reels is suppressed without correcting the deviation of tension, so that the
10 tension reels are operated at the fixed speed control.
In this case, when the deviation of tension falls within the predetermined range,
there is no problem, although there is a case where the deviation exceeds the predetermined
range depending on rolling state or condition of basic material. In this case, since the speed of
the tension reels is changed, the speed on the inlet side of the rolling mill is changed and the
15 plate thickness on the outlet side is varied.
Further, there is also a case where influence coefficient of the rolling mill is
changed due to the rolling state and the tension control in which the speed of the tension reels is
used as the operation end and the outlet-side plate thickness control in which a roll gap of the
rolling mill is used as the operation end are unstable. In such a case, it is difficult to make
20 control stably by the outlet-side plate thickness control in which the roll gap at the present state
is used as the control operation end, the tension speed control in which the tension reels are
operated at the fixed speed control and the tension torque fixed control in which the tension reels
are operated at the fixed torque control, so that oscillation in the plate thickness on the outlet side
of the rolling mill occurs.
25 The above problems are not limited to the tension reels but as far as tension is
exerted on the material to be rolled on the inlet and outlet sides of the rolling mill, the same
problem arises. As other examples of the structure that tension is exerted on the material to be
rolled on the inlet and outlet side of the rolling mill, there are a bridle roll, a pinch roll and the
like.
30 The subject to be solved in the present invention is to perform control of the
configuration in which tension is exerted on the material to be rolled on inlet and outlet sides of
the rolling mill and control of a roll gap of the rolling mill suitably to suppress oscillation in
thickness on the outlet side of the rolling mill.
According to an aspect of the present invention, a rolling control device which
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controls a rolling mill for rolling a material to be rolled by a pair of rolls comprises a roll gap
control part to control space between the rolls in the pair of rolls on the basis of tension of the
material inserted into the rolling mill to be rolled by the rolling mill or the material sent out from
the rolling mill after rolled and a speed control part to control carrying speed of the material
inserted into the rolling mill to be rolled by the rolling mill or the material sent out fiom the
rolling mill after rolled on the basis of thickness of the rolled material.
Further, according to another aspect of the present invention, a rolling control
method of controlling a rolling mill for rolling a material to be rolled by a pair of rolls comprises
controlling space between the rolls in the pair of rolls on the basis of tension of the material
inserted into the rolling mill to be rolled by the rolling mill or the material sent out from the
rolling mill after rolled and controlling carrying speed of the material inserted into the rolling
mill to be rolled by the rolling mill or the material sent out from the rolling mill after rolled on
the basis of thickness of the rolled material.
Furthermore, according to another aspect of the present invention, a rolling
control program of controlling a rolling mill for rolling a material to be rolled by a pair of rolls
by causing an information processing unit to execute the following steps including a step of
controlling space between the rolls in the pair of rolls on the basis of tension of the material
inserted into the rolling mill to be rolled by the rolling mill or the material sent out from the
rolling mill after rolled and a step of controlling carrying speed of the material inserted into the
rolling mill to be rolled by the rolling mill or the material sent out fiom the rolling mill after
rolled on the basis of thickness of the rolled material.
According to the present invention, control of the configuration in which tension
is exerted on the material to be rolled on inlet and outlet sides of the rolling mill and control of
the roll gap of the rolling mill can be performed suitably and oscillation in thickness of the
material on the outlet side of the rolling mill can be suppressed.
Other objects, features and advantages of the invention will become apparent
from the following description of the embodiments of the invention taken in conjunction with the
accompanying drawings.
30 BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 schematically illustrates the whole configuration of a rolling mill and a
rolling control device according to an embodiment of the present invention;
Fig. 2 illustrates the internal hnction of rolling thickness control, speed thickness
control, speed tension control and roll gap tension control according to the embodiment of the
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present invention;
Fig. 3 illustrates the internal fbnction of a control method selection device
according to the embodiment of the present invention;
Fig. 4 shows an operation example of an optimum control method decision device
according to the embodiment of the present invention;
Fig. 5 shows an operation example of the optimum control method decision
device according to the embodiment of the present invention;
Fig. 6 shows a database of a control method according to the embodiment of the
present invention;
Fig. 7 illustrates the internal fbnction of a control output selection device
according to the embodiment of the present invention;
Fig. 8 illustrates the fbnction of an inlet-side TR speed command device
according to the embodiment of the present invention;
Fig. 9 illustrates the fbnction of an inlet-side TR control device according to the
embodiment of the present invention;
Fig. 10 schematically illustrates the whole configuration of a rolling control
device in a prior art;
Fig. 11 illustrates an example of a rolling phenomenon in the prior art;
Fig. 12 illustrates an example of an inlet-side tension rolling phenomenon system
in the prior art;
Fig. 13 shows an example of the time series of parameters in the prior art;
Fig. 14 illustrates the relation of control operation end and control state amount of
a single-stand rolling mill in the prior art;
Fig. 15 illustrates an example of a single-stand rolling phenomenon in the prior
art;
Fig. 16 schematically illustrates a cross response of the single-stand rolling mill in
the prior art;
Fig. 17 illustrates the relation of the control operation end and the control state
amount of the single-stand rolling mill;
Fig. 18 illustrates the relation of operation end and control state amount
considering cross item; and
Fig. 19 illustrates the hardware configuration of a rolling control device according
to an embodiment of the present invention.
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DESCRIPTION OF THE EMBODIEMNTS
The present invention is now described in detail by taking a single-stand rolling
mill which is a representative rolling mill using tension reels for feeding and winding a material
to be rolled as an example. Fig. 10 schematically illustrates the control configuration of a
single-stand rolling mill S100. The single-stand rolling mill SlOO includes an inlet-side tension
reel 2 (hereinafter referred to as an inlet-side TR 2) disposed on an inlet side of a rolling mill 1 to
feed a material u to be rolled in a rolling direction (shown by arrow in Fig. 10) of the rolling mill
1 and an outlet-side tension reel 3 (hereinafter referred to as an outlet-side TR 3) disposed on
outlet side of the rolling mill 1 to wind the material u rolled by the rolling mill 1.
The inlet-side TR 2 and the outlet-side TR 3 are driven by electric motors and an
inlet-side TR control device 5 and an outlet-side TR control device 6 are provided as the motors
and devices for controlling to drive the motors. With such configuration, the rolling in the
single-stand rolling mill SlOO is performed by rolling the material u fed from the inlet-side TR 2
by the rolling mill 1 and then winding the rolled material u by the outlet-side TR 3.
In the rolling mill 1, a roll gap control device 7 which changes a roll gap which is
a distance between an upper work roll Rsl and a lower work roll Rs2 to control a thickness of
the rolled material u (thickness of a product) and a mill speed control device 4 which controls the
speed of the rolling mill 1 (peripheral speed of the upper and lower work rolls Rsl and Rs2) are
disposed. Upon rolling, a rolling speed setting device 10 produces a speed command to be
supplied to the mill speed control device 4 and the mill speed control device 4 controls the speed
of the rolling mill 1 (peripheral speed of the upper and lower work rolls Rsl and Rs2) to be
constant.
On the inlet side (left side of the rolling mill 1 in Fig. 10) and the outlet side of
the rolling mill 1 (right side of the rolling mill 1 in Fig. lo), tension is exerted on the material u
to perform rolling stably and efficiently. The tension necessary for that purpose is calculated by
an inlet-side tension setting device 11 and an outlet-side tension setting device 12. Further, an
inlet-side tension current conversion device 15 and an outlet-side tension current conversion
device 16 calculate current values for obtaining motor torque necessary for respective motors of
the inlet-side TR 2 and the outlet-side TR 3 on the basis of the inlet- and outlet-side tension set
values calculated by the inlet-side tension setting device 11 and an outlet-side tension setting
device 12 in order to exert inlet- and outlet-side set tension on the material u and supply the
respective current values to the inlet-side TR control device 5 and the outlet-side TR control
device 6.
The inlet-side TR control device 5 and the outlet-side TR control device 6 control
the currents of the motors to be equal to the respective currents supplied thereto so that
predetermined tension is given to the material u by respective motor torque given to the inletside
TR 2 and the outlet-side TR 3. The inlet-side tension current conversion device 15 and the
outlet-side tension current conversion device 16 calculate current set values (motor torque set
values) equal to the tension set values on the basis of a model of TR (tension reel) mechanical
system and TR control system.
However, since this control model contains error, actual tension measured by an
inlet-side tension meter 8 and an outlet-side tension meter 9 installed on the inlet and outlet sides
of the rolling mill 1 is used to correct the tension set values by inlet-side tension control 13 and
outlet-side tension control 14 and the corrected tension set values are supplied to the inlet-side
tension current conversion device 15 and the outlet-side tension current conversion device 16.
Thus, the inlet-side tension current conversion device 15 and the outlet-side tension current
conversion device 16 change the current values set in the inlet-side TR control device 5 and the
outlet-side TR control device 6.
Further, since the thickness of the material u is important in the quality of
products, thickness control is performed. More particularly, an outlet-side thickness control
device 18 controls the roll gap control device 7 on the basis of an actual thickness detected by an
outlet-side thickness meter 7 to thereby control a roll gap of the rolling mill 1, so that the
thickness on the outlet side of the rolling mill 1 (on the right side of the rolling mill 1 in Fig. 10)
is controlled.
The outlet-side TR 3 and the inlet-side TR 2 used for winding and feeding the
material in the single-stand rolling mill are controlled at fixed torque produced by the respective
motors. More particularly, motor current commands are corrected on the basis of the actual
tension detected by the inlet-side tension meter 8 and the outlet-side tension meter 9, so that the
tension exerted on the material u is controlled to be fixed. The torque of the respective motors
for the inlet-side TR 2 and the outlet-side TR 3 is obtained by motor currents and accordingly
there is also a case where the fixed torque control may be changed to the fixed current control.
When the TR (tension reel) is controlled at the fixed torque, there is a problem
that the TR control interferes with thickness control applied to the rolling mill to deteriorate the
accuracy in thickness on the outlet side. Since influence on the outlet-side thickness is effected
to the inlet-side tension larger than outlet-side tension, the problems in the rolling mill 1 and the
inlet-side TR 2 are described below.
Fig. 11 is a conceptual diagram illustrating a rolling phenomenon between the
inlet-side TR 2 and the rolling mill 1 of the single-stand rolling mill S100. As shown in Fig. 11,
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in the inlet-side TR 2, the sum of motor torque 22 which is an output of the inlet-side TR control
device 5 and tension torque 25 determined by inlet-side tension 24 (Tb) and mechanical
conditions (reel diameter D and reel gear ratio Gr), that is, the sum of the motor torque 22 and
the tension torque 25 is integrated to decide inlet-side TR (tension reel) speed 20. Further, J
5 represents inertial moment (kg rn2) of the inlet-side TR 2.
In the rolling mill 1, the outlet-side thickness 26 is determined from an added
value of a roll gap modification amount 23 (=AS) to a predetermined coefficient (M/(M+Q)) as
shown and an added value of inlet-side tension 24 of the rolling mill 1 to a predetermined
coefficient ((aP/i?Tb)/(M+Q)) as shown and inlet-side speed 21 of the rolling mill is determined
10 from the decided outlet-side thickness 25 by means of the constant mass-flow rule. Difference
between the inlet-side speed 21 of the rolling mill and the inlet-side TR speed 20 is integrated to
obtain the inlet-side tension 24. In Fig. 11, M represents a mill constant M(Wm), Q represents
a plastic coefficient Q(kN/m) and (aP/dTb)/(M+Q) represents an influence coefficient (kb) on
outlet-side thickness by variation of rolling load P(kN) by variation of inlet-side tension Tb.
15 As a basic rule in the rolling mill 1, there is the constant mass-flow rule. This is
shown by the following expression (1) by continuation of the material u on the inlet side of the
rolling mill 1 (on the left side of the rolling mill 1 in Fig. 10) and on the outlet side of the rolling
mill 1 (on the right side of the rolling mill 1 in Fig. 10).
20 H.Ve= h.Vo (1)
H: thickness on the inlet side of the rolling mill 1
h: thickness on the outlet side of the rolling mill 1
Ve: speed on the inlet side of the rolling mill 1
Vo: speed on the outlet side of the rolling mill 1
25
The expression (1) of the constant mass-flow rule means that when the inlet-side
thickness is constant, the outlet-side thickness is changed if the inlet-side speed is changed. In
case of the single-stand rolling mill (the single rolling mill 1 shown in Fig. lo), the inlet-side
speed is the inlet-side TR speed. The inlet-side TR 2 changes the inlet-side TR speed 20 so that
30 the tension torque 25 is equal to the motor torque 22, although this change is made by the inertia
of the inlet-side TR 2, the rolling mill 1 and the rolling phenomenon and there is no control
means for suppressing the change of the inlet-side speed 20.
I Accordingly, in the rolling mill 1, when AS of the roll gap modification amount
23 is operated in order to maintain the outlet-side thickness (thickness of the material u on the
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outlet side of the rolling mill 1) to be fixed by the thickness control, the inlet-side speed 21 of the
rolling mill (speed of the material u on the inlet side of the rolling mill 1) is changed
correspondingly to produce deviation ATb in the inlet-side tension 24. In order to suppress the
deviation, the inlet-side TR speed 20 is changed, although this change causes variation in the
outlet-side thickness. An inlet-side tension suppression system 27 performed by the inlet-side
TR 2 sometimes has a large time constant depending on the rolling conditions and there is a case
where the large time constant causes the outlet-side thickness variation having large surge.
The inlet-side tension 24 is suppressed even by the rolling phenomenon. When
the inlet-side tension 24 is changed, the rolling load P on the rolling mill 1 is changed and the
inlet-side speed 21 of the rolling mill is changed in response to it. The inlet-side tension 24 is
changed even by an inlet-side tension rolling phenomenon system 28. The response of the
inlet-side tension rolling phenomenon system 28 is very faster as compared with the inlet-side
tension suppression system 27 and accordingly the inlet-side rolling phenomenon of Fig. 11 can
be converted as shown in Fig. 12.
It can be understood from Fig. 12 that the roll gap modification amount 23 (=AS)
of the rolling mill 1 appears as the deviation ATb of the inlet-side tension 24 in phase and the
deviation is integrated by the inlet-side TR 2 to change the inlet-side TR speed 20.
Accordingly, the deviation ATb between the roll gap modification amount 23 (=AS) and the
inlet-side tension 24, the change of the inlet-side TR speed 20 and the change of the outlet-side
thickness have the relation as shown in Fig. 13. Fig. 13 shows the relation of the roll gap
modification amount 23, the inlet-side tension 24 (Tb), the inlet-side TR speed 20 and the outletside
thickness.
As shown in Fig. 13, when the roll gap modification amount 23 is changed, the
inlet-side speed of the rolling mill 1 is changed to vary the inlet-side tension 24. Since the
inlet-side TR 2 is controlled at the fixed torque, the inlet-side TR speed 20 is changed by the
inertial operation of the inlet-side TR in response to the variation of the inlet-side tension 24.
When the inlet-side TR speed 20 is changed, the outlet-side thickness variation occurs in
accordance with the constant mass-flow rule shown by the expression (1). When the outlet-side
thickness variation occurs, the outlet-side thickness control device 18 controls the roll gap
modification amount 23 to maintain the outlet-side thickness to be constant. When the series of
operations is continued, the outlet-side thickness is oscillated as shown in Fig. 13.
Actually, since the outlet-side thickness meter 17 is installed in the place far from
the rolling mill 1, a delay time exists until the outlet-side thickness used in the outlet-side
thickness control device 18 is detected, although the delay time can be neglected when the delay
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time is sufficiently shorter as compared with the oscillation period of the outlet-side thickness.
In order to prevent such oscillation of the outlet-side thickness, there is provided a
tension speed control device 42 which controls to maintain the tension between the tension reel
and the rolling mill to be a predetermined value and gives priority to the fact that the tension reel
speed is maintained to be fixed with respect to deviation from the tension set value within the
predetermined range so that variation of the tension reel speed is suppressed without correcting
the tension deviation. However, in this method, there arises the case where the outlet-side
thickness variation of the rolling mill cannot be suppressed by suppressing modification of the
tension reel speed.
The rolling mill has two control operation ends of the roll gap and the rolling
speed and two control state amounts of the outlet-side thickness and the inlet-side (or outlet-side)
tension of the rolling mill. When the two control operation ends are operated, the two control
state amounts are influenced to change the control state amounts. Fig. 14 shows the relation of
the control operation ends and the control state amounts in case of the single-stand rolling mill.
The rolling phenomenon of the single-stand rolling mill is as shown in Fig. 15 but this rolling
phenomenon is conceptually shown in Fig. 14.
In case of the single-stand rolling mill 1, the control operation ends include the
roll gap modification amount 23 and the inlet-side TR speed 20. Further, the control state
amounts include the outlet-side thickness 26 and the inlet-side tension 24 of the rolling mill.
When the roll gap modification amount 23 is changed, the outlet-side thickness 26 is changed by
an influence coefficient 503 (roll gap --, outlet-side thickness) and the inlet-side tension 24 is
changed by an influence coefficient 501 (roll gap -. inlet-side tension). Further, when the
inlet-side TR speed 20 is changed, the inlet-side tension 24 is changed by an influence
coefficient 502 (inlet-side TR speed --+ inlet-side tension) and the outlet-side thickness 26 is
changed by an influence coefficient 504 (inlet-side TR speed --, outlet-side thickness).
In the single-stand rolling mill 1, as shown in Fig. 10, the outlet-side thickness 26
of the rolling mill is controlled by changing the roll gap 23 by the outlet-side thickness control
device 18. Further, the inlet-side tension 24 is controlled by changing the inlet-side TR speed
20 by the inlet-side tension suppression system 27 as shown in Fig. 11.
When the influence coefficient 503 (roll gap --, outlet-side thickness) and the
influence coefficient 502 (inlet-side TR speed -+ inlet-side tension) are sufficiently larger as
compared with the influence coefficient 501 (roll gap --, inlet-side tension) and the influence
coefficient 504 (inlet-side TR speed -+ outlet-side thickness), this control configuration has no
problem, although, as described in JP-A-20 12- 176428, when the influence coefficient 503 (roll
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gap -, outlet-side thickness) and the influence coefficient 502 (inlet-side TR speed -, inlet-side
tension) are smaller as compared with the influence coefficient 501 (roll gap --+ inlet-side
tension) and the influence coefficient 504 (inlet-side TR speed -, outlet-side thickness), there
arises a problem that stable control cannot be made.
When such a state occurs, the thickness control device 18 controls the outlet-side
thickness 26 and accordingly even if the roll gap 23 is operated, the inlet-side tension 24 is
greatly varied. In order to control the variation, when the inlet-side tension suppression system
27 changes the inlet-side TR speed 20, the outlet-side thickness 26 is greatly changed. When
the outlet-side thickness is changed, the thickness control device 18 operates the roll gap 23 and
accordingly the outlet-side thickness 26, the inlet-side tension 24, the inlet-side TR speed 20 and
the roll gap 23 are oscillated at the same period.
The inlet-side rolling phenomenon of the single-stand rolling mill is as shown in
Fig. 12. Fig. 16 illustrates the same block diagram as Fig. 14 in which the inlet-side tension
suppression system 27 by the inlet-side TR 2 is removed, the inlet-side TR speed 20 and the roll
gap modification amount 23 are used as the control operation ends and the outlet-side thickness
26 and the inlet-side tension 24 are used as the control state amounts. Similarly to the case of
conversion from Fig. 11 to Fig. 12, the inlet-side tension rolling phenomenon system 28 is
arranged as an inlet-side tension influence coefficient 101. A primary delay time constant Tr
which is omitted in Fig. 12 since a response time is sufficiently shorter as compared with the
inlet-side tension suppression system 27 by the inlet-side TR 2 is left in Fig. 12. Influence
coefficients 11 1, 112, 113 and 114 of Fig. 17 are obtained from Fig. 16 as corresponding
influence coefficients 501, 502, 503 and 504 of Fig. 14.
It can be understood that the influence coefficient 114 (inlet-side TR speed -.
outlet-side thickness) and the influence coefficient 112 (inlet-side TR speed -, inlet-side tension)
are small if the outlet-side thickness 26 is thin and the inlet-side TR speed 20 is fast since Ve is
the inlet-side TR speed 20 and h is the outlet-side thickness 26 of the rolling mill. Further, the
primary delay time constant Tr contained in the inlet-side tension influence coefficient 10 1
becomes small. Accordingly, the influence coefficient 113 (roll gap -, outlet-side thickness)
becomes small. Further, the influence coefficient 11 1 (roll gap -, inlet-side tension) shortens
the response time. That is, when the outlet-side thickness 26 is thin and the inlet-side TR speed
20 is fast, the outlet-side thickness 26 of the rolling mill is difficult to change and the inlet-side
tension is apt to be changed at the time that the roll gap 23 is operated. In other words, the
influence coefficient 11 1 (roll gap -, inlet-side tension) is larger than the influence coefficient
113 (roll gap -+ outlet-side thickness). Moreover, the inlet-side tension 24 and the outlet-side
- 11 -
thickness 26 are difficult to change similarly at the time that the inlet-side TR speed 20 is
operated.
The inlet-side tension contains a rolling phenomenon item kb. The rolling
phenomenon item kb is also changed in accordance with the rolling speed and the outlet-side
thickness, although when the rolling phenomenon item kb is increased, the influence coefficient
112 (inlet-side TR speed -+ inlet-side tension) is smaller than the influence coefficient 114 (inletside
TR speed -. outlet-side thickness).
It can be understood from the foregoing description that there is a case where the
outlet-side thickness 26 is thin and the inlet-side TR speed 20 is fast, so that the influence
coefficient 113 (roll gap -. outlet-side thickness) is smaller than the influence coefficient 11 1
(roll gap -. inlet-side tension) and the influence coefficient 112 (inlet-side TR speed -+ inletside
tension) is smaller than the influence coefficient 114 (inlet-side TR speed -, outlet-side
thickness). In such a case, when the outlet-side thickness 26 is to be controlled by the thickness
control device 18 and the inlet-side tension 24 is to be controlled by the inlet-side tension
suppression system 27 as shown in Fig. 11, it is impossible to make stable control since influence
of the cross item is large.
In such a case, as shown in Fig. 18, a speed thickness control device 50 which
controls the outlet-side thickness 26 by the inlet-side TR speed 20 and a roll gap tension control
5 1 which controls the inlet-side tension 24 by the roll gap 23 can be employed to control the
outlet-side thickness 26 and the inlet-side tension 24 stably. In order to realize this method, it is
necessary to change the operation of the inlet-side TR 2 which is operated at the fixed torque
control (at the fixed current control) in the prior art to the fixed speed control operation.
Even if the response of the inlet-side tension suppression system 27 is
deteriorated, it is necessary to operate the inlet-side TR 2 at the fixed speed control. The inletside
tension suppression system 27 in Fig. 12 becomes a primary delay system of time constant
Tq by the conversion of equivalents. The time constant Tq is proportional to the inlet-side TR
speed 20 and the rolling phenomenon item kb and is inversely proportional to the outlet-side
thickness 26 of the rolling mill. Accordingly, when the rolling phenomenon item kb is
increased, the time constant Tq of the inlet-side tension suppression system 27 is increased and
the response of the inlet-side tension suppression system 27 is deteriorated. Further, in this
case, the influence coefficient 11 1 (roll gap -. inlet-side tension) in Fig. 14 is not increased and
accordingly it is considered that stable control can be made by the conventional thickness control
using the roll gap 23 and the tension control using the inlet-side tension suppression system 27.
In rolling facilities, the materials to be rolled made of various raw materials are
W6934
- 12-
rolled to have various thicknesses and the rolling speed is also variously changed. Accordingly,
there are the following cases of three kinds of capable of performing the outlet-side thickness
and the inlet-side tension control stably in accordance with the rolling state.
A) Thickness control for operating the roll gap and tension control by the inlet-side
tension suppression system for the inlet-side TR which is operated at the fixed torque control;
B Thickness control for operating the roll gap and speed tension control for
operating the speed of the inlet-side TR which is operated at the fixed speed control; and
c) Roll gap tension control for operating the roll gap and speed thickness control for
operating the speed of the inlet-side TR which is operated at the fixed speed control.
In order to stably perform thickness control and tension control of the rolling mill,
it is necessary to change the above control of three kinds to be used. A control configuration of
the single-stand rolling mill according to the embodiment for realizing the above control is
shown in Fig. 1. An outlet-side thickness deviation Ah detected by the outlet-side thickness
meter 17 is used to produce an operation command AASAt~o the roll gap by a rolling thickness
control 61 and produce an operation command AAVAt~o the inlet-side TR speed by a speed
thickness control 62. Further, the deviation ATb (inlet-side tension deviation) between the
actual inlet-side tension measured by the inlet-side tension meter 8 and the inlet-side tension set
value set by the inlet-side tension setting device 11 is used to produce an operation command
AAVmR to the inlet-side TR speed by a speed tension control 63 and produce an operation
command AAS~tRo the roll gap by a roll gap tension control 64.
Further, when the inlet-side TR 2 is operated at the fixed torque control, a value
obtained by adding a control output from the inlet-side tension control 13 which operates the
inlet-side tension set value in accordance with the deviation between the actual inlet-side tension
and the inlet-side tension set value to the inlet-side tension set value by the inlet-side tension
setting device 11 is converted into a current command to the inlet-side TR 2 by the inlet-side
tension current conversion device 15 to thereby produce the current command to an inlet-side TR
control device 66.
A control method selection device 70 makes selection as to whether the outletside
thickness variation and the inlet-side tension variation can be reduced at the maximum if
any of the control methods defined by the above-mentioned items A), B) and C) is applied in
accordance with the rolling state and supplies a roll gap operation command to the roll gap
control device 7 on the basis of the selection result. When the inlet-side TR speed is operated,
the control method selection device 70 supplies a speed operation command to an inlet-side TR
speed command device 65. The inlet-side TR speed command device 65 prepares an inlet-side
TR speed command on the basis of an inlet-side TR reference speed produced by a reference
speed setting device 19 and an inlet-side TR speed modification amount supplied from the
control method selection device 70 and supplies the inlet-side TR speed command to the inletside
TR control device 66.
The inlet-side TR control device 66 has an operation mode in which the fixed
torque control (fixed current control) is performed in accordance with the current command and
an operation mode in which the fixed speed control is performed in accordance with the speed
command and changes the operation mode in accordance with a command from the control
method selection device 70 to make operation.
Fig. 2 illustrates an example of the rolling thickness control 61, the speed
thickness control 62, the speed tension control 63 and the roll gap tension control 64 in block
diagram. This is an example of respective control configurations and any method other than
this example may be used to configure the control system. In the example of Fig. 2, each
control system adopts the integral control (I control) but proportional-plus-integral control (PI
control) or proportional-plus-integral-derivative control (PID control) may be adopted.
The rolling thickness control 6 1 is supplied with outlet-side thickness deviation
Ah=hfi-hef which is difference between an actual outlet-side thickness hfi and an outlet-side
thickness set value hef and is configured by integral control (I control) which integrates a
product obtained by multiplying the inputted outlet-side thickness deviation by adjustment gain
and conversion gain from the outlet-side thickness deviation into the roll gap. Deviation
between the integrated output and the last integrated output is calculated to produce a control
output AASAGC. Further, the speed thickness control 62 is supplied with the outlet-side
thickness deviation Ah and is configured by integral control (I control) which integrates a
product obtained by multiplying the inputted outlet-side thickness deviation by adjustment gain
and conversion gain from the outlet-side thickness deviation into inlet-side speed. Deviation
between the integrated output and the last integrated output is calculated to produce a control
output defined by the following expression (2).
A (q)AC C
where M represents a mill constant of the rolling mill and Q represents a plastic coefficient of the
material u to be rolled. Further, a speed thickness control command is outputted as a speed
modification ratio to the set speed.
The roll gap tension control 64 is supplied with the inlet-side tension deviation
ATb =Tbfib-Tbref which is difference between actual inlet-side tension value Tbfib and inlet-side
tension set value Tb,f and is configured by integral control (I control) which integrates a product
obtained by multiplying the inputted inlet-side tension deviation ATb by adjustment gain and
conversion gain from the inlet-side tension deviation ATb into the roll gap. Deviation between
the integrated output and the last integrated output is calculated to produce a control output
AASmR.
Further, the speed tension control 63 is supplied with the inlet-side tension
deviation ATb and is configured by integral control (I control) which integrates a product
obtained by multiplying the inputted inlet-side tension deviation ATb by adjustment gain and
conversion gain from the inlet-side tension deviation ATb into the inlet-side speed. Deviation
between the integrated output and the last integrated output is calculated to produce a control
output defined by the following expression (3).
A (-71 A TR
Fig. 3 schematically illustrates the control method selection device 70. The
control method selection device 70 includes an optimum control method decision device 71 and
a control output selection device 72. The optimum control method decision device 71 decides
any of the control methods described in the above items A), B) and C) to make control by the
decided control method. The control output selection device 72 selects any of outputs produced
by the rolling thickness control 61, the speed thickness control 62, the speed tension control 63
and the roll gap tension control 64 to be used and supplies control command to the roll gap
control device 7, the inlet-side TR speed command device 65 and the inlet-side TR control
device 66. That is, the optimum control method decision device 71 functions as a control mode
decision part.
Fig. 4 illustrates an operation outline of the optimum control method decision
device 71. In this operation, when the influence coefficient 11 1 (roll gap -, inlet-side tension)
is large, the control method C) is used to perform tension control by rolling and thickness control
by reel speed. When a tension correction time constant of the inlet-side tension suppression
system 27 is large, the control method B) is used to perform thickness control by rolling and
inlet-side tension control which operates TR speed. In other cases except the above, the control
method A) which is performed heretofore is selected.
Selection of any of the three control methods is decided as follows. It is
considered that the optimum control method is changed depending on a kind of steel of the
material to be rolled, the outlet-side thickness and the rolling speed. Accordingly, when the
kind of steel or the outlet-side thickness is changed, the rolling speed is divided into three or so
stages of low speed, middle speed and high speed and when the rolling speed reaches one of the
divided rolling speed during rolling, the roll gap is changed stepwise to examine change in the
inlet-side tension and the outlet-side thickness. In this case, the roll gap modification amount is
changed within the range where the product quality of the material is not influenced, so that the
roll gap can be changed even during rolling of the material. Further, when the roll gap is
changed stepwise, the above control method A) is selected.
In the embodiment, as shown in Fig. 4, the rolling speed is changed stepwise in
order of low speed, middle speed and high speed. This operation is performed in order to select
any of the above three control methods. However, even when the rolling operation is started
actually, the rolling speed is increased stepwise as shown in Fig. 4. Accordingly, the operation
as shown in Fig. 4 can be performed together with the usual rolling operation without reducing
the productivity.
The inlet-side tension modification amount and the outlet-side thickness
modification amount produced just aRer the roll gap is changed stepwise are measured to judge
which of the influence coefficient 114 (roll gap + inlet-side tension) and the influence
coefficient 112 (roll gap + outlet-side thickness) is larger. Further, the response time of the
inlet-side tension suppression system 27 is judged from change in the inlet-side tension in case
where the roll gap is operated stepwise.
For example, as shown in Fig. 4, the areas at low speed, middle speed and high
speed are determined in accordance with the rolling speed. This determination method may be
defined by dividing the rolling speed to the maximum speed into three parts equally or dividing
it on the basis of another proper standard. When the rolling speed falls in the area, stepwise
disturbance is added to the roll gap. The stepwise disturbance is added to change the inlet-side
tension and the outlet-side thickness.
Next, as shown in Fig. 5, parameters dTb, dh and Tbr are obtained from actual
values of the inlet-side tension and the outlet-side thickness deviation. These parameters can be
obtained from change situation of the actual values in the time direction by means of signal
processing. The control method A), B) or C) is selected from the relation of magnitude of the
obtained parameters dTb, dh and Tbr.
Selection of the control method A), B) or C) is judged on the basis of comparison
of the values calculated on the basis of the parameters dTb, dh and Tbr with predetermined
thresholds as shown in Fig. 5. For example, when a value calculated by (dh/href)/(dTb/Tbref)
is smaller than or equal to a selection value of the control method C) which is a predetermined
threshold, the control method C) is selected. Further, when Tbr is larger than or equal to a
e - 16-
selection value of the control method B) which is a predetermined threshold, the control method
B) is selected. The selection values of the control methods C) and B) can be previously
calculated on the basis of past actual values or simulation of the rolling mill to be set.
When the optimum control method selection processing is performed for the
5 stepwise changes 1,2 and 3 at low, middle and high speeds, the control methods A) for low
speed, the control method B) for middle speed and the control method C) for high speed are
selected as the optimum control method in the case shown in Fig. 4.
The control method selection device 70 performs the above optimum control
method decision procedure to change the control method to the obtained optimum control
10 method. In this case, the control method of the inlet-side TR is different in the control methods
A), B) and C) and accordingly there is also a case where the control method cannot be changed
during the rolling operation. In this case, the rolling operation is continued by the control
method A) and when the material of the same kind of steel and the same thickness is fed next
I time, the control method may be changed. The obtained optimum control method is recorded in
I 15 a database using the kind of steel and the outlet-side thickness of the material and the rolling
I speed as search conditions and when the material of the same kind is rolled next time, the rolling
I
is controlled in accordance with the optimum control method recorded in the database.
Fig. 6 shows a record example of the database. There is a case where the control
methods A), B) and C) cannot be changed during rolling operation depending on rolling
20 facilities, although the control method B) can be used instead of the control method A). By
doing so, in case of the material in which the control method A) is used at low speed and the
control method C) is optimum at high speed, the control method B) can be selected at low speed
and the control method C) can be selected at high speed, so that stable and high-accuracy rolling
operation can be attained in the whole speed area.
I
I
I 25 The above-mentioned method is an example of the decision procedure of the
I optimum control method but another method may be used. For example, the influence
coefficients shown in Fig. 17 are calculated numerically from the actual rolling value using a
rolling phenomenon model and the optimum control method can be selected from the magnitude
relation thereof.
I 30 Fig. 7 illustrates an operation outline of the control output selection device 72.
The control output selection device 72 is supplied with outputs from the rolling thickness control
61, the speed thickness control 62, the speed tension control 63 and the roll gap tension control
64 and the selection result of the control method from the optimum control method decision
device 71 and supplies the control command to the roll gap control device 7, the inlet-side TR
speed command device 65 and the inlet-side TR control device 66.
As shown in Fig. 7, in the control output selection device 72, the respective
outputs from the rolling thickness control 61, the speed thickness control 62, the speed tension
control 63 and the roll gap tension control 64 are supplied to gain controllers 73, 74, 75 and 76,
respectively. The gain controllers 73 to 76 are signal adjustment parts which multiply the
respective outputs of the rolling thickness control 6 1, the speed thickness control 62, the speed
tension control 63 and the roll gap tension control 64 by gains. The gains of the gain
controllers 73 to 76 are adjusted on the basis of the control method selection result of the
optimum control method decision device 71.
When the control method A) is selected, the output from the rolling thickness
control 61 is integrated to be supplied to the roll gap control device 7. Further, fixed torque
control mode selection is inputted to the inlet-side TR control device 66. Accordingly, the
gains of the gain controllers 74 to 76 are set to zero in accordance with the control method
selection result of the optimum control method decision device 71 and the gain of the gain
controller 73 is adjusted, so that the output of the rolling thickness control 61 is integrated by an
integration processing part 77. The fixed torque control mode selection is inputted to the inletside
TR control device 66 on the basis of the control method selection result of the optimum
control method decision device 71. In this case, the inlet-side TR control device 66 fbnctions as
a tension reel torque control part.
When the control method B) is selected, the output of the rolling thickness control
61 is integrated to be supplied to the roll gap control device 7 and the output of the speed tension
control 63 is integrated to be supplied to the inlet-side TR speed command device 65.
Accordingly, the gains of the gain controllers 74 and 75 are set to zero on the basis of the control
method selection result by the optimum control method decision device 71 and the gains of the
gain controllers 73 and 76 are adjusted. Further, the output of the rolling thickness control 61 is
integrated by the integration processing part 77 and the output of the speed tension control 63 is
integrated by an integration processing part 78.
When the control method C) is selected, the output of the speed thickness control
62 is integrated to be supplied to the inlet-side TR speed command device and the output of the
roll gap tension control 64 is integrated to be supplied to the roll gap control device 7.
Accordingly, the gains of the gain controllers 73 and 76 are set to zero on the basis of the control
method selection result by the optimum control method decision device 71 and the gains of the
gain controllers 74 and 75 are adjusted. Further, the output of the roll gap tension control 64 is
integrated by the integration processing part 77 and the output of the speed thickness control 62
is integrated by the integration processing part 78.
That is, the control path connected to the integration processing part 77 and the
roll gap control device 7 fbnctions as a roll gap control part. Further, the control path
connected to the integration processing part 78 and the inlet-side TR speed command device 65
5 fbnctions as a speed control part.
The method as shown in Fig. 7 can be used to change the control methods A), B)
and C) mutually even in the rolling operation in accordance with the rolling speed, for example.
In the inlet-side TR speed command device 65, as shown in Fig. 8, inlet-side TR speed VETR
prepared by the reference speed setting device 19 in consideration of the inlet-side backward
10 ratio b of the rolling mill from rolling mill speed VMILLde cided by the rolling speed setting
device 10 by means of operator's manual operation and the control command from the control
method selection device 70 are used to prepare an inlet-side TR speed command VET^^^ to be
supplied to the inlet-side TR control device 66.
Fig. 9 schematically illustrates the inlet-side TR control device 66. The inlet-
15 side TR control device 66 is supplied with the inlet-side TR speed command v ~ ~ ~frrome tfh e
inlet-side TR speed command device 65, the current command IETRset from the inlet-side tension
current conversion device and the fixed torque control mode from the control method selection
device 70 to supply current to the inlet-side TR 2. Here, the inlet-side TR 2 includes a
mechanical device of TR and an electric motor for operating it and the current to the inlet-side
20 TR 2 represents the current supplied to the motor.
The inlet-side TR control device 66 includes P control 661 and I control 662
which prepare current commands so that the speed command VE~&eafn d actual speed value
V Eare ~iden~tical with each other and current control 663 which makes control so that the
prepared current command 1E~~raenfd current IETRfl~ow~i ng through the motor of the inlet-side
25 TR 2 are identical with each other. When the fixed torque control mode is selected, the I
1 control 662 is replaced by the inlet-side TR current set value I E T Rfr~om~ t~he inlet-side tension I
i
I current conversion device 15. When the fixed torque control mode is not selected (fixed speed
! i control), the P control 661 and the I control 662 are changed in accordance with the inlet-side TR
i
speed deviation.
30 In this state, when the fixed torque control mode is selected, correction is made by
current correction 664 so that the inlet-side TR current command I~Tkeifs not changed
discontinuously. With such a configuration, the control mode of the inlet-side TR control
device can be changed freely from the fixed torque control to the fixed speed control and from
the fixed speed control to the fixed torque control even in the rolling operation, so that the
- 19-
control methods A), B) and C) can be changed freely.
By using the control configuration described above, the control methods A), B)
and C) can be changed in accordance with the rolling state, so that the control configuration
optimum to the outlet-side thickness control and the inlet-side thickness control can be selected.
Accordingly, the outlet-side thickness accuracy and the operation efficiency can be improved
greatly.
In the embodiment, as described in Fig. 7, the case where the gain to the output
which is not used in accordance with the control method among the outputs of the rolling
thickness control 61, the speed thickness control 62, the speed tension control 63 and the roll gap
tension control 64 is reduced to zero has been described as an example. In addition, the gains
may be made small instead of reducing the gains to zero, so that the outputs of the rolling
thickness control 61, the speed thickness control 62, the speed tension control 63 and the roll gap
tension control 64 may be mixed at the rate corresponding to the gains and the control methods
A), B) and C) may be used together.
Further, in the embodiment, in case of the control method C), for example, the
speed of the inlet-side TR 2 is adjusted to control the outlet-side thickness and the roll gap is
adjusted to control the tension of the material to be rolled. However, there is also a possibility
that the tension of the material is influenced by the speed adjustment of the inlet-side TR 2
depending on the rolling state. Further, there is also a possibility that the outlet-side thickness
is influenced by the roll gap adjustment.
In order to avoid such unintended influence, it is desirable that non-interacting
control is performed. As an aspect of the non-interacting control, in case of the control method
C), for example, in the control output selection device 72 shown in Fig. 7, AS calculated by the
integration processing part 77 is supplied to the roll gap control device 7 and the influence
degree on the speed calculated on the basis of AS and the rolling state is inputted to the
integration processing part 78. Thus, the influence on the thickness by adjustment of the roll
gap is considered in the integration processing part 78 and the output signal to the inlet-side TR
speed command device 65 is calculated in the integration processing part 78. That is, the
influence on the thickness by adjustment of the roll gap can be canceled. In such a noninteracting
control, the module for calculating the influence degree on the speed calculated on
the basis of the above AS and the rolling state hnctions as a roll gap adjustment interference
prediction part.
Further, in the control output selection device 72 shown in Fig. 7, l+(AVN)
calculated by the integration processing part 78 is inputted to the inlet-side TR speed command
device 65 and the influence degree on the tension calculated on the basis of l+(AVN) and the
rolling state is inputted to the integration processing part 77. Thus, the influence on the tension
by adjustment of tension reel speed is considered in the integration processing part 77 and the
output signal to the roll gap control device 7 is calculated in the integration processing part 77.
That is, the influence on the tension by adjustment of the tension reel speed can be canceled. In
such a non-interacting control, the module for calculating the influence degree on the tension
calculated on the basis of the foregoing l+(AVN) and the rolling state functions as a speed
adjustment interference prediction part.
On the other hand, in case of the control method B), for example, in the control
output selection device 72 shown in Fig. 7, AS calculated by the integration processing part 77 is
inputted to the roll gap control device 7 and the influence degree on the speed calculated on the
basis of AS and the rolling state is inputted to the integration processing part 78. Thus, the
influence on the tension by adjustment of the roll gap is considered in the integration processing
part 78 and the output signal to the inlet-side TR speed command device 65 is calculated in the
integration processing part 78. That is, the influence on the tension by adjustment of the roll
gap can be canceled.
Further, in the control output selection device 72 shown in Fig. 7, l+(AVN)
calculated by the integration processing part 78 is inputted to the inlet-side TR speed command
device 65 and the influence degree on the tension calculated on the basis of l+(AVN) and the
rolling state is inputted to the integration processing part 77. Thus, the influence on the
thickness by adjustment of tension reel speed is considered in the integration processing part 77
and the output signal to the roll gap control device 7 is calculated in the integration processing
part 77. That is, the influence on the thickness by adjustment of the tension reel speed can be
canceled.
Such non-interacting control is particularly effective when the control methods
A), B) and C) using the foregoing gain control are used together. For example, there is
considered the case where the control methods C) and B) are mixed to be performed at the rates
of 80% and 20%, respectively.
In this case, the gain of the gain controller 74 for adjusting the output of the roll
gap tension control 64 is set to 80% and the gain of the gain controller 73 for adjusting the output
of the rolling thickness control 61 is set to 20%. Similarly, the gain of the gain controller 75 for
adjusting the output of the speed thickness control 62 is set to 80% and the gain of the gain
controller 76 for adjusting the output of the speed tension control 63 is set to 20%.
In this case, since it is said that the rolling state is in the state that influence of
control by the control method C) is dominant, it is considered that the influence on the thickness
by adjustment of the roll gap and the influence on the tension by adjustment of the tension reel
speed are reduced. Accordingly, in such a case, the non-interacting control is set to be
ineffective, so that the control state can be simplified.
On the other hand, there is considered the case where the control methods C) and
B) are mixed to be performed at the rates of 60% and 40%, respectively. In this case, it is
supposed that the gain of the gain controller 74 for adjusting the output of the roll gap tension
control 64 is set to 60% and the gain of the gain controller 73 for adjusting the output of the
rolling thickness control 61 is set to 40%. Similarly, it is supposed that the gain of the gain
controller 75 for adjusting the output of the speed thickness control 62 is set to 60% and the gain
of the gain controller 76 for adjusting the output of the speed tension control 63 is set to 40%.
In this case, influence of control by the control method C) on the rolling state is
stronger, although it is said that influence of control by the control method B) also cannot be
neglected and accordingly it is said that influence on thickness by adjustment of the roll gap and
influence on tension by adjustment of the tension reel speed are to be considered. Therefore, in
such a case, the non-interacting control can be set to be effective to perform suitable control.
Such change of the non-interacting control can be decided on the basis of the ratio
of the gain of the gain controller 73 and the gain of the gain controller 74 and the ratio of the
gain of the gain controller 75 and the gain of the gain controller 76. For example, when a low
gain of two gains of which the sum is equal to 10Ph exceeds a predetermined value, it is judged
that control using the low gain is in the non-neglectable state and the non-interacting control is
made effective. Further, when the low gain is smaller than or equal to the predetermined value,
it is judged that influence of control using the low gain can be neglected and the non-interacting
control is made ineffective. Such a predetermined value is 20 or 30%, for example.
Further, in the embodiment, the speed command of the tension reel has been
described as an example. However, as far as the structure that the material to be rolled is
tensioned on the inlet and outlet sides of the rolling mill 1 is adopted, the same control operation
can be realized similarly without being limited to the tension reel and even in a bridle roll, a
pinch roll or the like.
Moreover, in the embodiment, the case where the tension meter 8 is provided for
tension control has been described as an example. Without being limited thereto, tension can
be presumed on the basis of difference between the actual output current value of the inlet-side
TR control device 66 and the current command value outputted by the inlet-side tension current
conversion device 15. For example, when the actual value is larger than the command value,
- 22 -
the inlet-side TR control device 66 is in the state that the tension of the material is being reduced
and accordingly it can be presumed that the tension at this time is higher than the tension set by
the inlet-side tension setting device 11.
Furthermore, in the embodiment, as described with reference to Figs. 4 and 5, the
control methods A), B) and C) are changed in accordance with the actual rolling value, although
any control method can be selected previously to be used continuously in accordance with
mechanical specifications and product specifications of the material. In such as case, the
database described in Fig. 6 can be used.
Further, in the embodiment, the control method of the inlet-side TR 2 has been
described, although the same configuration can be applied to the control method of the outletside
TR 3. When influence on the thickness by the outlet-side tension is large depending the
rolling mill and the kind of material to be rolled, there is also a case where it is efficient to
operate the outlet-side TR.
Furthermore, in the embodiment, the example in which the single-stand rolling
mill is supposed has been described, although the rolling mill is not limited to the single-stand
rolling mill and the present invention can be applied even to a multi-stand tandem rolling mill if
the tension reel is installed on the inlet side or the outlet side. That is, the whole multi-stand
tandem rolling mill is considered as a rolling mill and the same control as the above can be
performed for tension between a front rolling mill of the multi-stand rolling mill and the tension
reel and tension between the last rolling mill and the tension reel.
Moreover, the rolling control device having the control method selection device
70 described in Fig. 1 as a center is realized by combination of software and hardware. The
hardware for realizing the hnctions of the rolling control device according to the embodiment is
described with reference to Fig. 19. Fig. 19 is a block diagram illustrating the hardware
configuration of an information processing unit constituting the rolling control device according
to the embodiment. As shown in Fig. 19, the rolling control device according to the
embodiment has the same configuration as an information processing terminal such as a general
server and a PC (personal computer).
That is, the rolling control device according to the embodiment includes a CPU
(Central Processing Unit) 20 1, a RAM (Random Access Memory) 202, a ROM (Read Only
Memory) 203, an HDD (Hard Disk Drive) 204 and an I/F 205 which are connected through a bus
208. Further, the I/F 205 is connected to an LCD (Liquid Crystal Display) 206 and an
operation unit 207.
The CPU 201 is arithmetic operation means which controls operation of the
-
whole rolling control device. The RAM 202 is a volatile storage medium in which information
can be read therefrom and can be written therein and is used as a work area at the time that the
CPU 201 processes information. The ROM 203 is a non-volatile storage medium for reading
only and stores therein programs such as firmware.
5 The HDD 204 is a non-volatile storage medium in which information can be read
therefrom and can be written therein and stores therein OS (Operating System), various control
programs, application programs and the like. The VF 205 connects the bus 208 to various
hardware and network to be controlled. Further, the I/F 205 is used as an interface for
exchanging information between devices or inputting information to the rolling mill.
10 The LCD 206 is a visual user interface used by an operator to confirm the state of
the rolling control device. The operation unit 207 is a user interface such as a keyboard, a
mouse and the like used by the operator to input information to the rolling control device. With
such hardware configuration, programs stored in the ROM 203, the HDD 204 or a recording
medium such as an optical disk not shown are read out to be stored in the RAM 202 and the CPU
15 201 performs operation in accordance with the programs, so that software control part is
configured. The software control part configured thus and the hardware are combined to realize
the hnctions of the rolling control device according to the embodiment.
In the embodiment, the case where all functions are contained in the rolling
control device has been described as an example. In this manner, all hnctions may be realized
I
20 by a single information processing unit or functions may be dispersed in more information
processing units to be realized.
I It should be hrther understood by those skilled in the art that although the
foregoing description has been made on embodiments of the invention, the invention is not
limited thereto and various changes and modifications may be made without departing from the
25 spirit of the invention and the scope of the appended claims.

0 -
CLAIMS:
1. A rolling control device which controls a rolling mill (1, S 100) for rolling a
material (u) to be rolled by a pair of rolls (Rsl, Rs2), comprising:
a roll gap control part (7) to control space between the rolls (Rsl, Rs2) in the pair
of rolls on basis of tension of the material (u) inserted into the rolling mill to be rolled by the
rolling mill or the material (u) sent out fkom the rolling mill after rolled; and
a speed control part (4) to control carrying speed of the material (u) inserted into
the rolling mill to be rolled by the rolling mill or the material (u) sent out from the rolling mill
after rolled on basis of thickness of the rolled material (u).
2. A rolling control device according to Claim 1, wherein
the roll gap control part (7) is configured to implement hnction of controlling the
space between the rolls (Rsl, Rs2) in the pair of rolls on basis of the thickness of the rolled
material (u) and
the speed control part (4) is configured to implement hnction of controlling the
carrying speed of the material (u) inserted into the rolling mill to be rolled by the rolling mill or
the material (u) sent out from the rolling mill after rolled on basis of the tension of the material
(u) inserted into the rolling mill to be rolled by the rolling mill or the material (u) sent out from
the rolling mill after rolled, and
the rolling control device comprises a control mode decision part (71) to decide
execution modes of control based on the thickness of the rolled material (u) and control based on
the tension of the material (u) performed by the roll gap control part (7) and the speed control
part (4), respectively.
3. A rolling control device according to Claim 2, wherein
I the control mode decision part (71) decides a rate of influencing the control based
I
I on the thickness of the rolled material (u) and a rate of influencing the control based on the
I
I tension of the material (u) performed by the roll gap control part (7) and the speed control part
(4), respectively, and performs the control based on the thickness of the rolled material (u) and
the control based on the tension of the material (u) in accordance with the decided rates.
4. A rolling control device according to Claim 1, hrther comprising:
a roll gap adjustment interference prediction part which predicts influence on the
thickness of the material (u) by a control output of the space between the rolls (Rsl, Rs2) by the
! roll gap control part (7) to supply prediction result to the speed control part (4); and
a speed adjustment interference prediction part which predicts influence on the
tension of the material (u) by a control output of the carrying speed of the material (u) by the
-
speed control part (4) to supply prediction result to the roll gap control part (7), and wherein
the roll gap control part (7) controls the space between the rolls (Rsl, Rs2) in the
pair of rolls on basis of the tension of the material (u) and the prediction result of the influence
on the tension of the material (u) by the control output of the carrying speed of the material (u),
and
the speed control part (4) controls the carrying speed of the material (u) on the
basis of the thickness of the rolled material (u) and the prediction result of the influence on the
thickness of the material (u) by the control output of the space between the rolls (Rsl, Rs2).
5. A rolling control device according to Claim 3, hrther comprising:
a roll gap adjustment interference prediction part which predicts influence on the
thickness of the material (u) by a control output of the space between the rolls (Rsl, Rs2) by the
roll gap control part (7) to supply prediction result to the speed control part (4); and
a speed adjustment interference prediction part which predicts influence on the
tension of the material (u) by a control output of the carrying speed of the material (u) by the
speed control part (4) to supply prediction result to the roll gap control part (7), and wherein
the roll gap control part (7) controls the space between the rolls (Rsl, Rs2) in the
pair of rolls on basis of the tension of the material (u) and the prediction result of the influence
on the tension of the material (u) by the control output of the carrying speed of the material (u),
and
the speed control part (4) controls the carrying speed of the material (u) on the
basis of the thickness of the rolled material (u) and the prediction result of the influence on the
thickness of the material (u) by the control output of the space between the rolls (Rsl, Rs2),
the roll gap adjustment interference prediction part and the speed adjustment
interference prediction part produce the prediction results when the decided rates fall within a
predetermined range.
6. A rolling control device according to Claim 2, hrther comprising
a tension reel torque control part (66) which controls torque of a tension reel for
feeding the material (u) inserted into the rolling mill to be rolled by the rolling mill or a tension
reel for winding the material (u) sent out from the rolling mill after rolled, and wherein
the control mode decision part (71) decides the execution modes for the control
performed by the roll gap control part (7) and the speed control part (4) and the control
performed by the tension reel torque control part (66).
7. A rolling control device according to Claim 2 or 6, wherein
the control mode decision part (71) decides the execution modes of the control on
e - 26 -
basis of variation of a rolling state when the space between the rolls (Rsl, Rs2) is changed
stepwise during rolling.
8. A rolling control device according to Claim 1, wherein
the roll gap control part (7) presumes the tension of the material (u) on basis of
difference between a command value of electric power supplied to a tension reel for feeding the
material (u) inserted into the rolling mill to be rolled by the rolling mill or a tension reel for
winding the material (u) sent out from the rolling mill after rolled and an actual value of electric
power supplied actually.
9. A rolling control method of controlling a rolling mill (1, S 100) for rolling a
material (u) to be rolled by a pair of rolls (Rsl, Rs2), comprising:
controlling space between the rolls (Rsl , Rs2) in the pair of rolls on basis of
tension of the material (u) inserted into the rolling mill to be rolled by the rolling mill or the
material (u) sent out from the rolling mill after rolled; and
controlling carrying speed of the material (u) inserted into the rolling mill to be
rolled by the rolling mill or the material (u) sent out from the rolling mill after rolled on basis of
thickness of the rolled material (u).
10. A rolling control program of controlling a rolling mill (1, S 100) for rolling a
material (u) to be rolled by a pair of rolls (Rsl, Rs2) by causing an information processing unit to
execute the following steps of:
controlling space between the rolls (Rsl, Rs2) in the pair of rolls on basis of
tension of the material (u) inserted into the rolling mill to be rolled by the rolling mill or the
material (u) sent out from the rolling mill after rolled; and
controlling carrying speed of the material (u) inserted into the rolling mill to be
rolled by the rolling mill or the material (u) sent out from the rolling mill after rolled on basis of
thickness of the rolled material (u).
11. A rolling control device, substantially as herein described with reference to
accompanying drawings and examples.
12. A rolling control method, substantially as herein described with reference to
accompanying drawings and examples.
Dated this 29th day of November 2013
Agent for the Applicant