JP7743158B2 - Automatic plate thickness control method for rolling mill and automatic plate thickness control device for rolling mill - Google Patents

Description

The present invention relates to an automatic thickness control method for a rolling mill, which controls the thickness of rolled material, and an automatic thickness control device for a rolling mill.

For example, Patent Document 1 describes a technique for rolling a rolled material using a rolling mill. In the technique described in this document, the thickness of the rolled material is controlled by controlling the gap between the rolling rolls of the rolling mill based on the deviation in the thickness of the rolled material before rolling (entry thickness deviation). In the technique described in this document, the delay time from detecting the entry thickness deviation to controlling the gap is calculated.

JP 2012-135777 A

In the technology described in this document, the entry thickness deviation is broken down into frequency components, the phase lag is calculated for each frequency component, and the delay time is calculated based on the calculated phase lag. The relationship between frequency and phase lag is determined in advance from past rolling performance and computer simulations (see [0026] and Figure 3 of Patent Document 1). As a result, there is a risk of errors in the delay time due to changes in equipment characteristics, etc. As a result, the delay time may not be timed appropriately, and the accuracy of the thickness of the rolled material may be insufficient. Therefore, it is desirable to be able to accurately set the timing for controlling the gap between the rolling rolls.

The present invention therefore aims to provide an automatic thickness control method for a rolling mill, and an automatic thickness control device for a rolling mill, that can accurately set the timing for controlling the gap between the rolling rolls.

An automatic thickness control method for a rolling mill is a method for controlling the gap between rolls that roll a rolled material using a reduction device. The automatic thickness control method detects an entry-side thickness deviation, which is a deviation in the thickness of the rolled material before rolling, and detects an exit-side thickness deviation, which is a deviation in the thickness of the rolled material after rolling. The automatic thickness control method approximates the detected entry-side thickness deviation to the trigonometric function a sin x through frequency analysis to determine an entry-side amplitude value a. The automatic thickness control method approximates the exit-side thickness deviation detected at a portion of the rolled material corresponding to the portion where the entry-side thickness deviation was detected to the trigonometric function c sin(x-β) through frequency analysis to determine an exit-side amplitude value c and an exit-side phase lag β. The automatic thickness control method calculates a reduction position phase lag α at the position of the gap using relational expression (A) when the size of the gap between the rolls is assumed to be the trigonometric function b sin(x-α).
a sin x - b sin (x-α) = c sin (x-β) ... (A)
The automatic thickness control method converts the calculated reduction position phase delay α into a delay time deviation, which is a time delay. A predetermined control delay time is set based on the time from when a predetermined portion of the rolled material passes the entry thickness deviation detection position to when the predetermined portion reaches the gap position. The automatic thickness control method controls the gap by the reduction device based on the timing obtained by subtracting the delay time deviation from the predetermined control delay time.

An automatic thickness control device for a rolling mill includes a controller that outputs commands to a reduction device that controls the gap between rolls that roll a rolled material. The controller acquires detection results of an entry-side thickness deviation, which is the deviation in the thickness of the rolled material before rolling, and acquires detection results of an exit-side thickness deviation, which is the deviation in the thickness of the rolled material after rolling. The controller approximates the detected entry-side thickness deviation to the trigonometric function a sin x through frequency analysis to determine an entry-side amplitude value a. The controller approximates the exit-side thickness deviation detected at a portion of the rolled material corresponding to the portion where the entry-side thickness deviation was detected to the trigonometric function c sin(x-β) through frequency analysis to determine an exit-side amplitude value c and an exit-side phase lag β. The controller calculates a reduction position phase lag α at the position of the gap using relational expression (A) assuming that the size of the gap between the rolls is the trigonometric function b sin(x-α).
a sin x - b sin (x-α) = c sin (x-β) ... (A)
The controller converts the calculated reduction position phase delay α into a delay time deviation, which is a time delay. A predetermined control delay time is set based on the time from when a predetermined portion of the rolled material passes the detection position of the entry thickness deviation to when the predetermined portion reaches the position of the gap. The controller controls the gap by the reduction device based on the timing obtained by subtracting the delay time deviation from the predetermined control delay time.

The above-mentioned automatic thickness control method for a rolling mill and automatic thickness control device for a rolling mill can each accurately set the timing for controlling the gap between the rolling rolls.

FIG. 1 is a block diagram showing a rolling facility 1. 2 is a flowchart of the operation of the rolling equipment 1 shown in FIG. 1 . 2 is a diagram showing trigonometric functions approximated or assumed by the control timing determination means 63 shown in FIG. 1; FIG.

The rolling equipment 1 (automatic plate thickness control device) will be described with reference to Figures 1 to 3.

As shown in FIG. 1, the rolling equipment 1 is equipment that rolls the rolled material R using a rolling mill 10. The rolled material R rolled by the rolling equipment 1 is in the form of a plate. The rolled material R is, for example, a metal, specifically, for example, steel, alloy steel (such as stainless steel), special steel, aluminum, titanium, copper, etc. The rolling equipment 1 includes the rolling mill 10, a tension reel 20, an entry-side thickness detection unit 31, an exit-side thickness detection unit 32, an entry-side speed detection unit 41, an exit-side speed detection unit 42, a screw-down device 51, and a controller 60.

The rolling mill 10 is a device that rolls the rolled material R. The rolling mill 10 may cold roll or hot roll the rolled material R. The rolling mill 10 is equipped with multiple rolls (cylindrical or cylindrical members). The rolling mill 10 is equipped with rolling rolls 11 and backup rolls 13.

The rolling rolls 11 are rolls (work rolls) that come into contact with the rolled material R and roll it. The two rolling rolls 11 are arranged to sandwich the rolled material R from both sides in the thickness direction of the rolled material R. The two rolling rolls 11 are arranged with a gap S (roll gap) between them. The position of the gap S between the two rolling rolls 11 is referred to as the rolling position P11. The rolling position P11 is the position where the rolling rolls 11 apply a rolling load (roll down) to the rolled material R.

The backup rolls 13 support the rolling rolls 11. The backup rolls 13 support the rolling rolls 11 from the side opposite the rolled material R (rear side). The number of backup rolls 13 can be set to various numbers. In the example shown in FIG. 1, one backup roll 13 supports one rolling roll 11. In this example, a total of four rolls are provided in the rolling mill 10 (the rolling mill 10 is a four-high rolling mill). Alternatively, multiple backup rolls 13 may support one rolling roll 11. Alternatively, the backup roll 13 supporting the rolling roll 11 may be supported by a different backup roll 13. For example, the rolling mill 10 may be a cluster rolling mill, or may be a 12-high or 20-high cluster rolling mill.

The tension reel 20 winds and unwinds (pays out) the rolled material R. Two tension reels 20 are provided. The two tension reels 20 are provided on both sides of the rolling mill 10 (the entry side and exit side, described below), and comprise a first tension reel 21 and a second tension reel 22. For example, the rolled material R moves back and forth between the first tension reel 21 and the second tension reel 22. In this case, the rolling equipment 1 may be of a reverse type (equipment that performs reverse rolling). In the example shown in FIG. 1, the rolled material R is paid out from the first tension reel 21, rolled by the rolling mill 10, and wound onto the second tension reel 22. The rolled material R is then paid out from the second tension reel 22, rolled by the rolling mill 10, and wound onto the first tension reel 21. The rolled material R may move in only one direction (one direction) from the first tension reel 21 to the second tension reel 22. The rolling equipment 1 does not have to be a reverse type.

The following describes a state in which the rolled material R is moving in a certain direction (predetermined direction) (to the right in the example shown in Figure 1). In the direction of movement of the rolled material R, the upstream side relative to the rolling mill 10 is referred to as the entry side, and the downstream side relative to the rolling mill 10 is referred to as the exit side. Note that when the rolled material R moves in the "predetermined direction," the entry side and the exit side are reversed when the rolled material R moves in the opposite direction to the "predetermined direction" (left in Figure 1). Specifically, for example, the sensor used as the entry-side thickness detection unit 31 when the rolled material R moves in the predetermined direction is used as the exit-side thickness detection unit 32 when the rolled material R moves in the opposite direction to the predetermined direction. Furthermore, with regard to the control performed by the controller 60, the entry side and the exit side are reversed when the rolled material R moves in the predetermined direction and when the rolled material R moves in the opposite direction to the predetermined direction.

The entry thickness detection unit 31 detects the thickness of the rolled material R (on the entry side) before rolling. The entry thickness detection unit 31 is a sensor (entry thickness gauge) that detects the thickness of the rolled material R. The entry thickness detection unit 31 is provided to detect the deviation in the thickness of the entry rolled material R (entry thickness deviation ΔH (described later)). The entry thickness detection unit 31 may detect the thickness of the rolled material R in a non-contact manner, or by contacting the rolled material R (the same applies to the exit thickness detection unit 32).

The exit thickness detection unit 32 detects the thickness of the rolled material R after rolling (at the exit). The exit thickness detection unit 32 is a sensor (exit thickness gauge) that detects the thickness of the rolled material R. The exit speed detection unit 42 is provided to detect the deviation in the thickness of the rolled material R at the exit (exit thickness deviation Δh (described later)). Because the rolled material R is rolled by the rolling mill 10, the thickness detection result by the exit thickness detection unit 32 is smaller than the thickness detection result by the entry thickness detection unit 31.

The entry speed detection unit 41 detects the speed (entry speed V) of the rolled material R before rolling (at the entry side). The entry speed detection unit 41 detects the moving speed of the rolled material R entering the rolling mill 10. The entry speed detection unit 41 may detect the speed of the rolled material R in a non-contact manner, or by contacting the rolled material R (the same applies to the exit speed detection unit 42). The entry speed detection unit 41 is, for example, a roll (speed detection roll) that contacts the rolled material R (the same applies to the exit speed detection unit 42).

The exit speed detection unit 42 detects the speed (exit speed v) of the rolled material R after rolling (at the exit). The exit speed detection unit 42 detects the movement speed of the rolled material R as it leaves the rolling mill 10. Because the rolled material R is rolled by the rolling mill 10, the detection result of the exit speed detection unit 42 (exit speed v) is faster than the detection result of the entry speed detection unit 41 (entry speed V).

The reduction device 51 controls (adjusts) the gap S (roll gap value) between the rolls 11. By controlling the gap S, the reduction device 51 (reduction control device) controls the rolling load acting on the rolled material R. Specifically, for example, the reduction device 51 includes a hydraulic cylinder, a valve (e.g., a servo valve) that controls the hydraulic cylinder, and a wedge mechanism (not shown) that moves the roll 11 in response to the extension and contraction of the hydraulic cylinder.

The controller 60 controls the screw down device 51. The controller 60 is a computer that performs signal input/output, information storage, and calculations (judgments, calculations, etc.). Each function of the controller 60 is realized by executing a program stored in a memory unit (not shown) in a calculation unit (not shown). The controller 60 acquires (reads) the detection results of the entry thickness detection unit 31, the exit thickness detection unit 32, the entry speed detection unit 41, and the exit speed detection unit 42. The controller 60 automatically controls the thickness of the rolled material R by automatically controlling the gap S. The controller 60 includes a thickness control means 61 and a control timing determination means 63.

The thickness control means 61 controls the thickness of the rolled material R (it is a thickness control controller). The thickness control means 61 calculates the manipulated variable ΔS. The manipulated variable ΔS is a command (signal, command value) for the gap S, which is a command for the thickness of the rolled material R. The thickness control means 61 outputs the manipulated variable ΔS to the reduction device 51. The thickness control means 61 outputs the manipulated variable ΔS based on the timing determined by the control timing determination means 63 (details will be described later). The thickness control means 61 controls the gap S and the thickness of the rolled material R so that the thickness deviation (exit thickness deviation Δh) of the rolled material R (at the exit) after rolling by the rolling mill 10 approaches zero as closely as possible. The thickness control means 61 can control the thickness of the rolled material R using various control methods. Specifically, for example, the thickness control means 61 may perform feedforward thickness control (predictive control) or mass flow thickness control.

The control timing determination means 63 determines (calculates) the timing for controlling the gap S. Specifically, the control timing determination means 63 determines the timing for outputting the manipulated variable ΔS from the thickness control means 61 to the screw-down device 51. More specifically, the control timing determination means 63 calculates the delay time (TD-T) described below (details will be provided later).

(Operation)
The automatic thickness control method is performed as follows. The rolling equipment 1 (mainly the controller 60) is configured to operate as follows. An overview of the operation of the rolling equipment 1 (an overview of the automatic thickness control method) is as follows. Each step of the flowchart shown in FIG. 2 will be explained below with reference to FIG. 2. The rolling equipment 1 (e.g., the entry thickness detection unit 31) shown in FIG. 1 detects the entry thickness deviation ΔH (step S1). The control timing determination means 63 determines the entry amplitude value a (see FIG. 3) of the entry thickness deviation ΔH (step S2). The rolling equipment 1 (e.g., the delivery thickness detection unit 32) detects the delivery thickness deviation Δh (step S3). The control timing determination means 63 determines the delivery amplitude value c (see FIG. 3) and the delivery phase lag β (see FIG. 3) of the delivery thickness deviation Δh (step S4). The control timing determination means 63 calculates the reduction position phase lag α (see FIG. 3), converts the reduction position phase lag α into a delay time deviation T (step S5), and determines the delay time (TD-T) (step S6). The thickness control means 61 then controls the gap S between the rolls 11 based on the determined delay time (TD-T) (step S7). The controller 60 repeats these processes until the calculation is completed (step S8). Details of the operation of the rolling equipment 1 (details of the automatic thickness control method) are as follows.

In step S1, the rolling equipment 1 detects the entry thickness deviation ΔH. The entry thickness deviation ΔH is the deviation in the thickness of the rolled material R before rolling. Specifically, the entry thickness deviation ΔH is waveform information indicating the thickness that changes over time (the same applies to the delivery thickness deviation Δh). A specific example of detecting the entry thickness deviation ΔH is as follows: The entry thickness detection unit 31 detects the entry thickness of the rolled material R. The controller 60 reads (acquires) the detection result (thickness) of the entry thickness detection unit 31. The controller 60 then calculates (acquires) the entry thickness deviation ΔH based on the read thickness. Note that the calculation of a value by the controller 60 is included in the "acquisition" of a value by the controller 60.

In step S2, the control timing determination means 63 approximates the detected inlet thickness deviation ΔH to the trigonometric function a sin x (see Figure 3) through frequency analysis to determine the inlet amplitude value a (see Figure 3). More specifically, the control timing determination means 63 performs frequency analysis on the inlet thickness deviation ΔH to decompose it into multiple frequency components. The control timing determination means 63 selects (uses) a predetermined frequency component from the multiple frequency components. The x in the trigonometric function a sin x (see Figure 3) is expressed as x = 2πft. Here, f is the frequency (Hz) of the frequency component selected from the multiple frequency components. t is time (e.g., seconds). It is preferable that the control timing determination means 63 selects (uses) the frequency component with the largest amplitude from the multiple frequency components. Furthermore, the frequency component selected from the multiple frequency components may be one, or two or more (multiple). When two or more frequency components are selected from a plurality of frequency components, the control timing determination means 63 preferably selects the frequency components in descending order of amplitude (such as the frequency with the largest amplitude, the frequency with the second largest amplitude, and so on). The following mainly describes the case where one frequency component is selected.

In step S3, the rolling equipment 1 detects the delivery thickness deviation Δh. The delivery thickness deviation Δh is the deviation in the thickness of the rolled material R after rolling. A specific example of detecting the delivery thickness deviation Δh is the same as the specific example of detecting the entry thickness deviation ΔH described above (however, entry is read as exit, e.g., entry thickness detection unit 31 is read as exit thickness detection unit 32).

In step S4, the control timing determination means 63 approximates the delivery thickness deviation Δh detected at the location (position, part) of the rolled material R where the entry thickness deviation ΔH was detected to the trigonometric function c sin(x-β) (see Figure 3) through frequency analysis.

The "portion (position, part) of the rolled material R where the entry thickness deviation ΔH was detected" refers to the same portion (the same portion) or substantially the same portion (substantially the same portion) of the rolled material R where the entry thickness deviation ΔH was detected. For example, the controller 60 tracks the position of the entry detection portion of the rolled material R to determine the position of the entry detection portion of the rolled material R after it has passed the detection position for the entry thickness deviation ΔH. Specifically, when a certain portion of the rolled material R (referred to as the "entry detection portion") is at the detection position for the entry thickness deviation ΔH (of the entry thickness detection unit 31), the entry thickness deviation ΔH is detected (Step S1). The controller 60 tracks the position of the moving entry detection portion. This entry detection portion reaches the detection position for the exit thickness deviation Δh (of the exit thickness detection unit 32). At this time, the exit thickness deviation Δh is detected (Step S3). Then, the control timing determination means 63 approximates the detected delivery thickness deviation Δh to a trigonometric function (step S4).

In step S4, the control timing determination means 63 decomposes the delivery thickness deviation Δh into multiple frequency components through frequency analysis. The control timing determination means 63 selects a predetermined frequency component from the multiple frequency components. At this time, the control timing determination means 63 uses, from the multiple frequency components, the frequency component used when approximating the entry thickness deviation ΔH to a trigonometric function in step S2. The x in the trigonometric function c sin(x-β) is expressed as x = 2πft. f is the frequency (Hz) of the frequency component selected in step S2. t is time (e.g., seconds). t = 0 is defined as the time when the same part (or approximately the same part) as the entry detection part where the value of the trigonometric function a sin x approximating the entry thickness deviation ΔH is 0 is located at the detection position for the delivery thickness deviation Δh.

In step S4, the control timing determination means 63 approximates the delivery thickness deviation Δh to the trigonometric function c sin(x-β) (see Figure 3) to determine the delivery amplitude value c (see Figure 3) and the delivery phase lag β (see Figure 3). As shown in Figure 3, the delivery phase lag β is the phase lag of the trigonometric function c sin(x-β) that approximates the delivery thickness deviation Δh relative to the trigonometric function a sin x that approximates the entry thickness deviation ΔH. If the delivery phase lag β is zero, the output timing of the control variable ΔS (the timing of controlling the gap S) shown in Figure 1 is appropriate, and the reduction position phase lag α (see Figure 3), described below, is appropriate (e.g., optimal). On the other hand, if the delivery phase lag β (see Figure 3) is not zero, the output timing of the control variable ΔS deviates from the appropriate timing, and the reduction position phase lag α is not appropriate (e.g., optimal). Therefore, in the next step S5, the control timing determination means 63 calculates an appropriate roll position phase delay α and sets the output timing of the manipulated variable ΔS to an appropriate value.

In step S5, the control timing determination means 63 determines the roll position phase lag α (see Figure 3). More specifically, the control timing determination means 63 determines the roll position phase lag α based on the inlet amplitude value a, the outlet amplitude value c, and the outlet phase lag β shown in Figure 3. Details of how to determine the roll position phase lag α will be described later.

In step S5, the control timing determination means 63 shown in Figure 1 calculates the delay time deviation T based on the calculated reduction position phase delay α (see Figure 3). The control timing determination means 63 converts the reduction position phase delay α, which is a phase delay (angle), into the delay time deviation T, which is a time delay (e.g., seconds). Specifically, the delay time deviation T is calculated by T = α/(2πf), where f is the frequency of the frequency component used when approximating the entry thickness deviation ΔH to the trigonometric function a sin x by frequency analysis in step S2.

In step S2, multiple frequency components may be selected from the multiple frequency components obtained by frequency analysis of the inlet thickness deviation ΔH. In this case, the control timing determination means 63 determines the reduction position phase lag α for each of the selected multiple frequency components, and determines the "delay time deviation T' for each frequency component" for each of the determined reduction position phase lags α. The control timing determination means 63 may then use the result of a comprehensive evaluation of the delay time deviations T' for each frequency component as the delay time deviation T.

In step S6, the control timing determination means 63 determines the timing for outputting the manipulated variable ΔS to the reduction device 51. Specifically, the control timing determination means 63 determines the delay time (TD-T). The delay time is the time from when a certain portion (predetermined portion) of the rolled material R passes the detection position for the inlet thickness deviation ΔH to when the thickness control means 61 outputs the manipulated variable ΔS (a command to reduce the predetermined portion with the rolling rolls 11) to the reduction device 51.

The control timing determination means 63 sets the delay time to the value (TD-T) obtained by subtracting the delay time deviation T from the predetermined control delay time TD. The predetermined control delay time TD is the time (or a time set based on this time) from when a certain portion of the rolled material R (a predetermined portion) passes the detection position for the entry thickness deviation ΔH to when this predetermined portion reaches the reduction position P11 (the position of the gap S). Setting the delay time to the predetermined control delay time TD raises the following problem. There is a delay in the control of the thickness by the thickness control means 61. More specifically, there is a delay between when the thickness control means 61 transmits the manipulated variable ΔS to the reduction device 51 and when the work roll 11 actually moves based on this manipulated variable ΔS. Therefore, if the delay time is set to the predetermined control delay time TD, the timing of the control of the gap S will be delayed from the appropriate timing. This delay is equivalent to the reduction position phase delay α.

The control timing determination means 63 therefore determines the delay time (TD-T) as the time obtained by subtracting the delay time deviation T from the predetermined control delay time TD. For example, if the predetermined control delay time TD is set to the base delay time, the control timing determination means 63 corrects (modifies) the delay time from the base delay time (predetermined control delay time TD) to the delay time (TD-T). The control timing determination means 63 advances the timing of control of the gap S by the delay time deviation T relative to the base delay time (predetermined control delay time TD). The control timing determination means 63 then transmits the delay time (TD-T) to the thickness control means 61. Note that the value of the delay time deviation T can be both positive and negative. For example, depending on the method of calculating the predetermined control delay time TD, the timing of control of the gap S may be earlier than appropriate when the delay time is set to the predetermined control delay time TD. In this case, the timing of control of the gap S must be delayed relative to the predetermined control delay time TD. In such cases, the delay time deviation T may become a negative value.

The delay time deviation T is calculated in real time (or near real time) based on the actual data (detected values) of the entry thickness deviation ΔH and the delivery thickness deviation Δh. Therefore, compared to when the delay time deviation T is set without being based on actual data, such as when the delay time deviation T is pre-stored, the delay time (TD-T) can be calculated with greater accuracy, and the appropriate output timing of the manipulated variable ΔS can be obtained.

In step S7, the rolling equipment 1 controls the gap S using the screw down device 51 based on the delay time (TD-T) (the timing obtained by subtracting the delay time deviation T from the predetermined control delay time TD). More specifically, the plate thickness control means 61 outputs an operation amount ΔS to the screw down device 51 at a timing based on the delay time (TD-T). The screw down device 51 controls the gap S between the rolls 11 in accordance with the operation amount ΔS.

The controller 60 performs control at each predetermined sampling period. Therefore, in step S7, the controller 60 may convert the delay time (TD-T), which is time information, into information on the number of sampling times ΔK. For example, the controller 60 converts the delay time (TD-T) into the number of sampling times ΔK using the following formula:
ΔK=(TD-T)・V/Ls
Here, V is the inlet speed (e.g., m/sec) detected by the inlet speed detection unit 41. Ls is the sampling length (e.g., m). The sampling length Ls is the length (unit control length) that the inlet rolled material R moves during the time (one sampling period) that the controller 60 performs control for one sampling count.

In step S8, the controller 60 determines whether or not to continue the calculation. If the calculation is to be continued (YES in step S8), the controller 60 returns the flow to step 1 and continues the calculation. If the calculation is to be ended (NO in step S8), the controller 60 ends the calculation. For example, the controller 60 may end the calculation when rolling a predetermined amount of rolled material R has been completed.

(Details of step S5)
As described above, in step S5, the control timing determination means 63 determines the roll position phase lag α (see FIG. 3) based on the entry amplitude value a (see FIG. 3), the delivery amplitude value c (see FIG. 3), and the delivery phase lag β (see FIG. 3). Specifically, the size of the gap S between the work rolls 11 is assumed to be the trigonometric function b sin(x-α) (see FIG. 3). The control timing determination means 63 determines the roll position phase lag α at the roll position P11 (position of the gap S) using the following relational expression (A):
a sin x - b sin (x-α) = c sin (x-β) ... (A)

Here, the "size of the gap S between the rolling rolls 11, 11" (roll gap value) assumed to be the trigonometric function b sin(x-α) is not the manipulated variable ΔS for controlling the gap S, but the actual size of the gap S between the rolling rolls 11, 11 (actual roll gap position). Furthermore, the assumption of this trigonometric function b sin(x-α) is an assumption for determining the reduction position phase delay α (for determining the timing for controlling the gap S). The thickness control means 61 does not need to control the size of the gap S to be b sin(x-α). As described above, the thickness control means 61 controls the gap S, for example, by feedforward thickness control or mass flow thickness control.

The details of calculating the reduction position phase lag α are as follows. The following equation (1), which combines sine functions with different phases, is known. This equation can be applied to calculate the phase lag of the gap S relative to the entry thickness deviation ΔH.

Substituting -α for α, -b for b, and -β for β in equations (1), (1-1), and (1-2), we obtain the following equations.

Equation (2) is the above equation (A). In equation (A), a sin x (see Figure 3) is a component that approximates the entry thickness deviation ΔH as a trigonometric function. In equation (A), c sin(x-β) is a component that approximates the delivery thickness deviation Δh as a trigonometric function (see Figure 3). In equation (A), b sin(x-α) (see Figure 3) is a component that corresponds to the gap S when the size of the gap S is assumed to be expressed in trigonometric arithmetic.

In equations (2-1) and (2-2), a, c, and β are known values that can be detected (measured). Specifically, a is detected by the entry-side thickness detection unit 31, and c and β are detected by the delivery-side thickness detection unit 32. Meanwhile, in equations (2-1) and (2-2), b and α are unknowns. Because there are two unknowns in the two equations (equations (2-1) and (2-2)), the known values a, b, and β can be substituted into the two equations and the simultaneous equations solved to determine the reduction position phase lag α.

The above equation (A) is expressed as a sine (sin) function, but this function may be transformed and expressed as a cosine (cos) function. In this invention, approximating or assuming a sine function and approximating or assuming a cosine function are the same in content, with only differences in expression.

(Effects of the first invention)
The effects of the automatic thickness control method of the rolling mill 10 shown in Figure 1 are as follows: The automatic thickness control method is a method of controlling the gap S between the rolls 11, 11 that roll the rolled material R by the reduction device 51.

[Configuration 1-1] The automatic thickness control method detects an entry thickness deviation ΔH, which is the deviation in thickness of the rolled material R before rolling. The automatic thickness control method detects an exit thickness deviation Δh, which is the deviation in thickness of the rolled material R after rolling. The automatic thickness control method approximates the detected entry thickness deviation ΔH to the trigonometric function a sin x (see FIG. 3) by frequency analysis to determine an entry amplitude value a (see FIG. 3). The automatic thickness control method approximates the exit thickness deviation Δh, which is detected at a portion of the rolled material R corresponding to the portion where the entry thickness deviation ΔH was detected, to the trigonometric function c sin(x-β) (see FIG. 3) by frequency analysis to determine an exit amplitude value c (see FIG. 3) and an exit phase lag β (see FIG. 3). In the automatic thickness control method, the roll reduction position phase delay α (see FIG. 3) at the position of the gap S is calculated using relational expression (A) assuming that the size of the gap S between the rolling rolls 11 is the trigonometric function b sin(x-α) (see FIG. 3).
a sin x - b sin (x-α) = c sin (x-β) ... (A)
The automatic thickness control method converts the calculated reduction position phase delay α (see FIG. 3) into a time delay, ie, a delay time deviation T. Note that the relational expression (A) may be expressed by a cosine function.

[Configuration 1-2] The predetermined control delay time TD is set based on the time from when a predetermined portion of the rolled material R passes the detection position for the entry thickness deviation ΔH to when this predetermined portion reaches the position of the gap S. The automatic thickness control method controls the gap S using the screw down device 51 based on the timing obtained by subtracting the delay time deviation T from the predetermined control delay time TD.

In the above [Configuration 1-1], the delay time deviation T is calculated based on the detected entry thickness deviation ΔH (actual data) and the detected delivery thickness deviation Δh (actual data). In the above [Configuration 1-2], the gap S is controlled based on the timing obtained by subtracting the delay time deviation T from the predetermined control delay time TD. Therefore, the delay time (TD-T) can be set with greater precision than, for example, when the gap S is controlled based on pre-stored timing. Therefore, the timing for controlling the gap S between the rolls 11 can be set with greater precision. As a result, the accuracy of the thickness of the rolled material R rolled by the rolling mill 10 can be improved.

(Effects of the second invention)
[Configuration 2] The automatic thickness control method uses the frequency component with the maximum amplitude when approximating the inlet thickness deviation ΔH to the trigonometric function a sin x (see FIG. 3) by frequency analysis.

The above [Configuration 2] allows the timing of control of the gap S to be set with greater precision using simpler calculations.

(Effects of the third invention)
The effects of the rolling equipment 1 (automatic thickness control device for the rolling mill 10) are as follows: The automatic thickness control device includes a controller 60. The controller 60 outputs a command to a reduction device 51 that controls the gap S between the rolls 11 that roll the rolled material R.

[Configuration 3-1] The controller 60 acquires the detection result of the entry thickness deviation ΔH, which is the deviation in the thickness of the rolled material R before rolling. The controller 60 acquires the detection result of the delivery thickness deviation Δh, which is the deviation in the thickness of the rolled material R after rolling. The controller 60 approximates the detected entry thickness deviation ΔH to the trigonometric function a sin x (see FIG. 3) by frequency analysis to determine the entry amplitude value a (see FIG. 3). The controller 60 approximates the delivery thickness deviation Δh, which is detected at a portion of the rolled material R corresponding to the portion where the entry thickness deviation ΔH was detected, to the trigonometric function c sin(x-β) (see FIG. 3) by frequency analysis to determine the delivery amplitude value c (see FIG. 3) and the delivery phase lag β (see FIG. 3). The controller 60 calculates the reduction position phase delay α (see FIG. 3) at the position of the gap S using the relational expression (A) when it is assumed that the size of the gap S between the rolls 11 is the trigonometric function b sin(x-α) (see FIG. 3).
a sin x - b sin (x-α) = c sin (x-β) ... (A)
The controller 60 converts the calculated roll position phase delay α (see FIG. 3) into a time delay, ie, a delay time deviation T. Note that the relational expression (A) may be expressed by a cosine function.

[Configuration 3-2] The predetermined control delay time TD is set based on the time from when a predetermined portion of the rolled material R passes the detection position for the entry thickness deviation ΔH to when this predetermined portion reaches the position of the gap S. The controller 60 controls the gap S using the screw down device 51 based on the timing obtained by subtracting the delay time deviation T from the predetermined control delay time TD.

In the above [Configuration 3-1], the delay time deviation T is calculated based on the detected entry thickness deviation ΔH (actual data) and the detected delivery thickness deviation Δh (actual data). Then, in the above [Configuration 3-2], the gap S is controlled based on the timing obtained by subtracting the delay time deviation T from the predetermined control delay time TD. Therefore, the delay time (TD-T) can be set with greater precision than, for example, when the gap S is controlled based on pre-stored timing. Therefore, the timing for controlling the gap S between the rolls 11 can be set with greater precision. As a result, the accuracy of the thickness of the rolled material R rolled by the rolling mill 10 can be improved.

(Effects of the fourth invention)
[Configuration 4] The controller 60 uses the frequency component with the maximum amplitude when approximating the inlet thickness deviation ΔH to the trigonometric function a sin x (see FIG. 3) by frequency analysis.

The above [Configuration 4] allows the timing of control of the gap S to be set with greater precision using simpler calculations.

(Modification)
The above-described embodiments may be modified in various ways. For example, the number of components of the above-described embodiments may be changed, or some of the components may not be provided. For example, modified examples of the above-described embodiments may be combined in various ways. For example, the connections of the components shown in FIG. 1 may be changed. For example, the arrangement of the components may be changed. For example, the inclusion relationships of the components may be changed in various ways. For example, a component described as a lower-level component included in a higher-level component may not be included in this higher-level component, but may be included in another component. For example, what is described as multiple different components or parts may be combined into a single component or part. For example, what is described as a single component or part may be provided as multiple different components or parts. For example, the order of the steps in the flowchart shown in FIG. 2 may be changed, or some steps may not be performed. For example, each component may have only a portion of its features (function, arrangement, shape, operation, etc.).

1. Rolling equipment (automatic thickness control device)
REFERENCE SIGNS LIST 10 Rolling mill 11 Rolling roll 51 Screw down device 60 Controller a Entry amplitude value c Exit amplitude value R Rolled material S Gap T Delay time deviation TD Predetermined control delay time α Rolling position phase delay β Exit phase delay ΔH Entry thickness deviation Δh Exit thickness deviation

Claims (4)

An automatic thickness control method for a rolling mill that controls the gap between rolls that roll a rolled material using a reduction device,
Detecting an inlet thickness deviation, which is a deviation in the thickness of the rolled material before rolling;
Detecting an outlet thickness deviation, which is a deviation in the thickness of the rolled material after rolling;
The detected entry thickness deviation is decomposed into a plurality of entry frequency components by frequency analysis,
selecting a predetermined input frequency component from the decomposed input frequency components;
an input amplitude value a is calculated when the selected predetermined input frequency component is approximated by a trigonometric function a sin x;
The delivery thickness deviation detected at a portion corresponding to the portion of the rolled material where the entry thickness deviation was detected is decomposed into a plurality of delivery frequency components by frequency analysis;
selecting an output frequency component having the same frequency as the predetermined input frequency component from the plurality of output frequency components;
An output amplitude value c and an output phase delay β are calculated when the selected output frequency component is approximated by a trigonometric function c sin(x-β),
The roll gap is assumed to be a trigonometric function b sin(x-α), and a rolling position phase delay α at the position of the gap is calculated using a relational expression (A).
a sin x - b sin (x-α) = c sin (x-β) ... (A)
The calculated roll position phase delay α is converted into a delay time deviation, which is a time delay,
The gap is controlled by the screw down device based on a timing obtained by subtracting the delay time deviation from a predetermined control delay time that is set based on the time from when a predetermined portion of the rolled material passes the detection position of the entry-side thickness deviation to when the predetermined portion reaches the position of the gap.
Automatic thickness control method for rolling mills. The automatic thickness control method for a rolling mill according to claim 1,
When approximating the inlet thickness deviation to the trigonometric function a sin x by frequency analysis, the frequency component with the maximum amplitude is used.
Automatic thickness control method for rolling mills. a controller that outputs a command to a reduction device that controls the gap between the rolls that roll the rolled material;
The controller
Obtain a detection result of an inlet thickness deviation, which is a deviation in the thickness of the rolled material before rolling;
Obtain a detection result of an outlet thickness deviation, which is a deviation in the thickness of the rolled material after rolling;
The detected entry thickness deviation is decomposed into a plurality of entry frequency components by frequency analysis,
selecting a predetermined input frequency component from the decomposed input frequency components;
an input amplitude value a is calculated when the selected predetermined input frequency component is approximated by a trigonometric function a sin x;
The delivery thickness deviation detected at a portion corresponding to the portion of the rolled material where the entry thickness deviation was detected is decomposed into a plurality of delivery frequency components by frequency analysis;
selecting an output frequency component having the same frequency as the predetermined input frequency component from the plurality of output frequency components;
An output amplitude value c and an output phase delay β are calculated when the selected output frequency component is approximated by a trigonometric function c sin(x-β),
The roll gap is assumed to be a trigonometric function b sin(x-α), and a rolling position phase delay α at the position of the gap is calculated using a relational expression (A).
a sin x - b sin (x-α) = c sin (x-β) ... (A)
The calculated roll position phase delay α is converted into a delay time deviation, which is a time delay,
The gap is controlled by the screw down device based on a timing obtained by subtracting the delay time deviation from a predetermined control delay time that is set based on the time from when a predetermined portion of the rolled material passes the detection position of the entry-side thickness deviation to when the predetermined portion reaches the position of the gap.
Automatic thickness control device for rolling mills. The automatic plate thickness control device for a rolling mill according to claim 3,
The controller
When approximating the inlet thickness deviation to the trigonometric function a sin x by frequency analysis, the frequency component with the maximum amplitude is used.
Automatic thickness control device for rolling mills.