JPH0530522B2 - - Google Patents

Description

Detailed Description of the Invention <Industrial Application Field> The present invention relates to a roll eccentricity compensating device for a rolling mill that prevents plate thickness fluctuations caused by back-up roll eccentricity in a hydraulic rolling mill that rolls metal strips. .

<Conventional technology> Despite efforts to improve the processing accuracy of rolling rolls in rolling mills, there are always small roll eccentricities such as poor roundness and misalignment between the body and shaft. exists. A strip rolled using such eccentric rolls has periodic thickness fluctuations in its length direction.

Therefore, as a means to solve the above problems,
Japanese Patent Publication No. 53-16386 ``Roll eccentricity compensation device for rolling mill'' has already been disclosed.

This equipment focuses on the fact that the cycle of rolling force fluctuations due to disturbances other than roll eccentricity is sufficiently longer than that due to roll eccentricity, and has been developed under certain stable conditions during rolling, namely, constant rolling force and constant rolling speed after the strip is bitten. Below, the rolls of the upper and lower back-up rolls calculated and stored in the previous cycle are shown, taking advantage of the fact that there is reproducibility between rolling force fluctuations due to roll eccentricity from one roll rotation to the second and subsequent rotations. Compensation control for plate thickness fluctuations caused by roll eccentricity is performed using a rolling force fluctuation signal based on a composite waveform of eccentricity.

Next, an example of a conventional device is shown in FIG. In the figure, 1a and 1b indicate upper and lower work rolls of the rolling mill, 2a and 2b indicate upper and lower back-up rolls of the rolling mill, and 3 indicates a strip to be rolled.
4 is a rolling force detector that detects the difference between the set rolling force and the actual rolling force and outputs a rolling force fluctuation signal P; 5 is a rolling force detector that detects the rotation angle of the upper back-up roll 2a and outputs n pulses for one rotation thereof; oscillating pulse oscillator,
Reference numeral 6 denotes a reduction position detector that detects the difference between the set reduction position and the actual reduction position of the reduction cylinder 17 and outputs a reduction position deviation signal S, and 8 a sampler that samples the signal from the calculator 9 in synchronization with the pulse. ,
10 is a counter for counting the pulses, 12
is a converter that multiplies the rolling position deviation signal S by the rolling force conversion coefficient K _M and converts it into a rolling force fluctuation conversion signal P _S ;
9 is an arithmetic unit that outputs a result obtained by subtracting the conversion signal P _S from the rolling force fluctuation signal P. Reference numeral 20 denotes a reduction device, which is composed of a servo amplifier 15, a servo valve 16, and a reduction cylinder 17.

The first pulse of the pulse oscillator 5 is the beginning of the first cycle of roll eccentricity, and the rolling force fluctuation (P-P _S ) is sampled by the sampler 8 via the calculator 9 by the pulse, and the A/D The converter 13 converts it into a digital quantity and stores it in the computer ₁₁ as P11. In the same way, P ₁₂ , P ₁₃ , ..., P _1o are changed to the computer 1 by the second, third, ..., n-th pulse.
1 is stored.

At the next pulse at the end of the first period of roll eccentricity, that is, the (n+1)th pulse, the computer 11 stores the rolling force fluctuation at that time as _P21 , issues a signal A, and resets the counter 10. Further, the calculator 11 calculates rolling force fluctuations P _R1 , P _R2 , . . . , P _R(o-1) , P _Ro due to roll eccentricity at each sampling point using the following equation.

P _R2 =P ₁₂ −P ₂₁ −P ₁₁ /n−P ₁₁ , P _R3 =P ₁₃ −P ₂₁ −P ₁₁ /
n×2−P ₁₁ ,...,P _Ro = P _1o −P ₂₁ −P ₁₁ /n×(n− 1)−P ₁₁ Note that the rolling force fluctuation P ₁₁ detected by the first pulse Since the rolling force fluctuation due to roll eccentricity included in is set as zero based on the first period of roll eccentricity, P _R1 =P _Ro+1 =0.

In the second cycle of roll eccentricity, the calculator 11 stores P ₂₁ , P ₂₂ , ..., P _2o in the same manner as in the first cycle, and in synchronization with the pulse, calculates the rolling force fluctuation P due to the roll eccentricity obtained by the above calculation. _R1 ,P _R2 ,…,P _Ro
This signal is output as a compensation signal B for rolling force fluctuations due to roll eccentricity. This signal is sent to D/A converter 1
8 converts it into an analog signal and sends it to the converter 19, and divides the rolling force fluctuation signal including this roll eccentricity compensation signal by the rolling force conversion coefficient K _M to convert the rolling force correction signal into a rolling position correction signal.

This rolling position correction signal is compared with the rolling position correction signal S from the rolling position detector 6 by a comparator 14 to control the rolling device 20, thereby controlling the plate thickness while compensating for roll eccentricity.

When the second cycle is completed, the rolling force fluctuation due to roll eccentricity is calculated in the same way as the first cycle, and this and the calculated value from the previous first cycle are added to calculate the new rolling force due to roll eccentricity. It is assumed to be variable. Hereinafter, similar calculations are performed for the third and subsequent cycles to control the thickness of the strip plate 3.

<Problems to be Solved by the Invention> However, since the conventional device detects the roll rotation angle of only one side of the upper or lower back up rolls, if the diameter difference between the upper and lower back up rolls is large, As the detection error increases, the difference between the calculated and stored compensation signal and the composite waveform of the roll eccentricity of the vertical back-up roll in the next cycle increases, resulting in a compensation error and poor plate thickness control stability. Easy to diverge. This tendency becomes remarkable when the difference in diameter between the upper back-up roll and the lower back-up roll becomes 2% or more.

<Means for solving the problems> The roll eccentricity compensation device for a rolling mill according to the present invention has the following features:
In a plate thickness control device for a rolling mill, comprising a rolling roll rolling down device, a rolling position detector, a rolling force detector, a roll rotation angle detector, an arithmetic unit, a sampler, a calculator, and a control device that controls the rolling down device. , a first roll rotation angle detector connected to the upper back up roll, a second rotation angle detector connected to the lower back up roll, signals from the first roll rotation angle detector and the arithmetic unit. A first sampler receives signals and inputs them to the computer, and a second sampler receives signals from the second roll rotation angle detector and the arithmetic unit and inputs the signals to the computer.

<Operation> The first roll rotation angle detector and the second roll rotation angle detector detect the rotation angles of the upper back-up roll and the lower back-up roll, respectively, and send detection signals to the first sampler and the second sampler, respectively. send. The first sampler and the second sampler each sample the rolling force signal from the calculator in synchronization with the pulse, and input the signal to the computer. The computer separates, detects and stores the variation in rolling force caused by the eccentricity of the upper back up roll using the respective input signals and the pulse signal from the first roll rotation angle detector. At the same time, a variation in rolling force due to eccentricity of the lower back-up roll is separated, detected and stored using the pulse signal from the second roll rotation angle detector. This detected rolling force fluctuation is combined with the upper and lower fluctuations as a roll eccentricity compensation signal in the cycle following the cycle in which this detection storage operation was performed, and
By controlling the rolling position, fluctuations in plate thickness due to roll eccentricity are eliminated.

<Example> Hereinafter, an example of the present invention will be described in detail with reference to FIGS. 1 to 3, and the same parts as those of the conventional device are given the same reference numerals and redundant explanation will be omitted.

In FIG. 1, 5a is a first pulse oscillator installed on the upper back up roll 2a, 5b is a second pulse oscillator installed on the lower back up roll 2b, which detects the rotation angle of each roll. Each oscillates n pulses for one rotation (one period) and inputs them directly to the computer 11, further inputs each count value to the computer 11 via the first counter 10a and the second counter 10b, and First sampler 8a and second sampler 8
It is sending a message to b. The first sampler 8a and the second sampler 8b each have a computing unit 9 and a first A/D
It is connected to the computer 11 via a converter 13a and a second A/D converter 13b.

When rolling the strip 3, the first pulse oscillator 5
A and the first pulse of the second pulse oscillator 5b are set as the beginning of the first cycle of roll eccentricity of each of the back-up rolls 2a and 2b, and the pulse generates a rolling force fluctuation signal P and a rolling force fluctuation conversion signal P _S The difference (P-P _S ) between the
The pulses from a and the second pulse oscillator 5b are sampled in synchronization with each other, and converted into digital quantities by the first A/D converter 13a and the second A/D converter 13b, and then sent to the computer 1 as P _a11 and P _b11 .
1 separately.

Similarly, each second, third,..., nth pulse causes P _a12 , P _a13 ,..., P _a1o and
P _b12 , P _b13 , ..., P _b1o are stored in the computer 11.

The next pulse at the end of the first cycle of each roll eccentricity, i.e. the n+1th pulse, causes the computer 11
stores the rolling force fluctuations at that time as P _a21 and P _b21 and issues signals A ₁ and A ₂ to reset the first counter 10a and the second counter 10b, respectively.

In addition, the calculator 11 calculates the rolling force fluctuations P _Rai1 , P Rbl1 , P _Rbl1 , due to each roll eccentricity at each sampling point.
Calculate P _Rbl2 ,..., P _Rblo using the following formula.

C _aij =P _aij −P _a(i+1)1 −P _ai1 /n(j−1)−P _ai1 ……
(1) P _Raij =P _Ra(i-1)j +C _aij −1/n+1 _o+1 〓 ^j ′ ⁼¹ C _aij ′ …(2) C _blk =P _blk −P _b(l+1) − P _bl1 /n(k-1)-P _bk1 ...(3) P _Rblk =P _Rb(l-1)k +C _blk -1/n+1 _o+1 〓 ^k ′ ⁼¹ C _blk ′
...(4) In the above formulas (1) to (4), i represents the i-th rotation of the upper back-up roll, l represents the l-th rotation of the lower back-up roll, and j and k represent j of each pulse oscillator. represents the k-th and k-th pulses.

Due to the nature of the periodic function, the rolling force fluctuation due to roll eccentricity (P _Raij ) obtained from the rolling force fluctuation sampled at the timing of the first pulse oscillator using the above formula is a rolling force fluctuation signal due to the eccentricity of only the upper back-up roll. becomes.

Similarly, the rolling force fluctuation ( _PRblk ) due to roll eccentricity sampled and calculated at the timing of the second pulse oscillator becomes a rolling force fluctuation signal due to eccentricity of only the lower back up roll.

In the first cycle of each back-up roll, only the rolling force fluctuation due to roll eccentricity is stored, and the compensation signal B for the rolling force fluctuation is not output.

From the second cycle of each backup roll, 1
The rolling force fluctuations due to each roll eccentricity stored before the cycle are added together using the following formula in synchronization with each pulse oscillator, and the result is output as a compensation signal B for rolling force fluctuations due to roll eccentricity.

B=αP _Raij +βP _Rblk ...(5) α+β=1 (0<α<1, 〇<β<1) Next, rolling force fluctuation due to roll eccentricity C _aij ,
Explain C _blk . Although only the upper back-up roll eccentric period will be described here, the same applies to the lower back-up roll eccentric period.

Now, let the rolling force fluctuation value be P _a , of which C _a is due to roll eccentricity, and P〓 is that due to other disturbances, P _a = C _a + P〓 ...(6) Also, roll eccentricity Paying attention to the fact that has periodicity, and expressing the values at the beginning and end of the period with subscripts 0 and 1, respectively, P _a1 −P _a0 =C _a1 −C _a0 +P〓 ₁ −P〓 ₀ ≒ P〓 ₁ −P〓 ₀ ……(7) (∵C _a1 ≒C _a0 ) In other words, by taking the difference between the rolling force fluctuation signals detected at the beginning and end of one cycle of roll eccentricity, it is possible to calculate the rolling force due to roll eccentricity. It is possible to obtain the rolling force fluctuation value P〓 due to other disturbances other than the force fluctuation value C _a .

Furthermore, as shown in Figure 2a, the rolling force fluctuation value P due to disturbances such as entrance plate thickness fluctuations and temperature fluctuations has a period that is sufficiently long compared to the period of roll eccentricity, so the rolling force fluctuation value P〓 due to disturbances such as entrance plate thickness fluctuations and temperature fluctuations is long enough in comparison to the period of roll eccentricity. If so, it is possible to obtain an approximate value P〓' of the rolling force fluctuation due to factors other than roll eccentricity, which connects the sampling start point and end point with a straight line at the beginning and end of one cycle. Then, by subtracting this P〓' from the total rolling force variation value P _a , it becomes possible to obtain the waveform of the rolling force variation value C _a due to roll eccentricity, as shown in FIG. 2b.

Note that sampling of rolling force fluctuations is performed separately by the first sampler 8a and the second sampler 8b in synchronization with each pulse of the first pulse oscillator 5a and the second pulse oscillator 5b.

_{Therefore ,} as _{shown in} FIG.
Compensation signal B is synthesized from P _Ra1 and P _Rb1 sampled by the following formula.

B=αP _Ra1 +βP _Rb1 (8) Based on this compensation signal, the rolling device 20 is operated to adjust the gap between the upper and lower work rolls 1a and 1b, thereby controlling the thickness of the material to be rolled 3.

P _Ra2 in the second cycle T _a2 is sampled in the same way as the first cycle T _a1 , but in the first cycle T _a1 , P _a 〓 ₁ due to factors other than P _Ra1 is calculated by P _a 〓'. Also, due to minute changes in roll eccentricity and other disturbances between the first period T _a1 and the second period T _a2 , it does not become zero but remains somewhat as shown in FIG. 3. Therefore, the third period T _a3 is
The rolling force fluctuation due to the eccentricity of the upper back-up roll is compensated by the signal B _a2 of the rolling force fluctuation due to the roll eccentricity of the upper back-up roll obtained in the first and second round, and similarly, the rolling force fluctuation due to the eccentricity of the lower back-up roll is compensated. The rolling force fluctuations are compensated by the signal (B _b2 ). The sum of these compensation signals is output as compensation signal B.

By performing similar control for the fourth and subsequent cycles, roll eccentricity compensation control is performed that corrects the error in the roll eccentric signal ( _PPS ) due to the linear approximation, the gradual change in roll eccentricity, and other disturbances.

<Effects of the Invention> A first roll rotation angle detector and a first sampler, a second roll rotation angle detector and a second sampler are provided, and the roll eccentricity waveforms of the upper back-up roll and the lower back-up roll are respectively separated during rolling. By detecting this, more accurate roll eccentricity compensation control can be performed regardless of the diameter difference between the upper and lower back up rolls.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a roll eccentricity control device as an embodiment of the present invention, FIG. 2 is a waveform diagram showing an example of rolling force fluctuations due to disturbances and roll eccentricity during rolling, and FIG. The fourth is a waveform diagram showing the relationship between the rolling force fluctuation due to roll eccentricity at each rotation period of the roll, the rolling force fluctuation detection signal, and the roll eccentricity compensation signal, and the fourth is a block diagram showing an example of a conventional method. In the drawing, 1a is an upper work roll, 1b is a lower work roll, 2a is an upper back-up roll,
2b is a lower back up roll, 3 is a strip plate, 4 is a rolling force detector, 5a is a first pulse oscillator, 5b is a second pulse oscillator, 6 is a rolling position detector, 8a is a first sampler, 8b is a second 11 is a computer, 14 is a comparator, and 20 is a reduction device.

Claims (1)

[Scope of Claims] 1. A hydraulic pressure-down device; a pressure-down position detector that detects the difference between a set pressure-down position and an actual pressure-down position and outputs a pressure-down position deviation signal;
A rolling force detector detects the difference between the set rolling force and the actual rolling force and outputs a rolling force fluctuation signal, and a back-up roll rotation angle detector detects the rotation angle of the back-up roll and outputs pulses according to the rotation. , an arithmetic unit that calculates a rolling force variation based on a signal obtained by converting the rolling position deviation signal into a rolling force and the rolling force variation signal; a sampler that samples the rolling force variation in synchronization with the pulse; A plate thickness control device for a rolling mill comprising a calculator and a reduction control device for controlling the hydraulic reduction device, comprising: a first roll rotation angle detector installed on an upper back roll of the rolling mill; a second roll rotation angle detector installed on the roll; and a first sampler that samples rolling force fluctuations produced by the calculator in synchronization with pulses from the first roll rotation angle detector and inputs the results to the calculator. , a second sampler for sampling rolling force fluctuations by the calculator in synchronization with the pulses of the second roll rotation angle detector and inputting the samples to the calculator, and inputs from the first and second samplers are provided. Based on the rolling force fluctuations and the pulses input from the first and second roll rotation angle detectors, the rolling force fluctuations due to roll eccentricity are detected for each cycle of roll rotation for each of the upper and lower back-up rolls. , calculated and stored by the calculator in correspondence with the rotation angle of each roll, and the calculated and stored rolling force fluctuations associated with the eccentricity of the upper and lower rolls are applied to the cycle following the cycle in which this calculation and storage operation was performed. A roll eccentricity compensating device for a rolling mill, characterized in that the roll eccentricity compensation signal is synthesized as a roll eccentricity compensation signal, and the rolling position is controlled by a rolling down control device based on the roll eccentricity compensation signal to eliminate plate thickness variation due to roll eccentricity. .