JPS5897417A - Controlling device for roll eccentricity - Google Patents

Abstract

PURPOSE:To eliminate the phase lag of hydraulic rolling down, by providing a device used for obtaining the eccentricity frequency of back up rolls by counting phase signals for a fixed time and a function generator outputting the phase signals in accordance with said frequency to calculate the quantity of roll eccentricity earlier by the number of pulses equivalent to that of said phase signals. CONSTITUTION:Pulse signals (i), detected by pulse generators 3 attached to the shaft ends of back up rolls 2, are transmitted to a Fourier series expanding device 4 and to a device 5 used for determining the predicting angle of phase lag, and at the same time, signals detected by a load cell 6 are transmitted to said device 4. Further, the signals are respectively outputted from the device 5 to the device 4, and from the device 4 to a servovalve 8 used for controlling the quantity and pressure of a hydraulic oil fed to a hydraulic rolling down device 7. Thus, the phase lag of hydraulic rolling down can be eliminated by constituting the controlling system as mentioned above.

Description

[Detailed Description of the Invention] The present invention makes it possible to accurately control plate thickness by eliminating the rolling phase delay of a hydraulic rolling device when controlling plate thickness variations due to eccentricity of a rolling mill backing roll. The present invention relates to a roll eccentricity control device.

If the eccentricity of the rolling mill backing roll is removed, the plate thickness accuracy can be improved and a plate of better quality can be obtained4. However, the hydraulic rolling machine of the rolling mill has a rolling phase lag, and this phase lag Therefore, the phase of the roll eccentricity analysis value may shift, and control to sufficiently eliminate roll eccentricity may not be possible. This is especially true during roll acceleration/deceleration, when the analysis data results cannot catch up with the roll eccentricity frequency, and removal of roll eccentricity tends to be delayed. An object of the invention is to provide a roll eccentricity control device that can eliminate the rolling phase delay of a hydraulic rolling device and obtain a product with accurate plate thickness when controlling plate thickness by eccentricity of a rolling mill backing roll. It has a pulse generator for measuring the rotation angle of the backing roll and a device for Fourier analysis of the rolling load signal detected by the load detector as the fundamental wave of the backing roll period. A device that uses the analyzed 7-lier coefficient to generate a backing roll thinning signal in response to a pulse, includes a device that counts pulse signals for a certain period of time to determine the eccentric frequency of the backing roll, and outputs a phase that corresponds to the frequency. The present invention is characterized in that a function unit is provided to calculate the amount of roll eccentricity earlier by a pulse corresponding to the phase thereof, thereby correcting a phase delay under hydraulic pressure.

The present invention will be explained below with reference to the drawings. 1. First, the basic principle of roll eccentricity detection will be explained 3.
, The relationship between roll eccentricity and rolling load can be expressed by the following formula.

However, Δp, rolling load fluctuation ΔS due to o-ru eccentricity
: Roll eccentricity variation component K; Mill constant M of the rolling mill; Plasticity constant of rolling stripping Since the roll eccentricity variation component ΔS matches the rotation period of the backing roll, ΔS−ΔSo CO3 (0) t + β)...
...... (11) However, ΔSo; eccentricity ω of the backing roll; angular velocity t of the backing roll; time β; the phase change equation (i) from the position of the roll to the position of the eccentricity is expressed by equation (11 ), and accordingly, the roll eccentricity can be determined if ΔPC is detected. Generally, rolling load fluctuations include many components with different frequencies. Therefore, the number of rotations x (L) of the backup roll is set to Y
If the rolling load P is shown on the Y-axis, the rolling load P can be expressed as a Fourier series as follows.

0 p=-+A, cosωx+ A2 CO82ω, z+-
・-=-B, ,9iaωx+B2nn2ωx+ =-
...(iv) Therefore, from equation (1■), the roll eccentricity fluctuation component ΔS is the roll eccentricity fluctuation component ΔS, which is expressed by the equation (1v) and (
v), Fourier analysis of rolling load fluctuation is performed and Δp
It can be obtained by calculating e3.Also, in order to perform Fourier analysis of equations (1■) and (), numerical analysis must be used.3゜The period of the function shown in Figure 1 is 2N. (t-0, 1, 2,...
, 2N) Therefore, N 0-cos πt (vi) 0-R eccentricity corresponds to one period of load fluctuation of the backing roll, so this is the case when 2=1. However, although the value of P(2N) in the first period and the value of P(0) at the beginning should be theoretically the same, as shown in Figure 1, they are not actually the same, so P(0 ) and P(2N) need to be linearly corrected according to the difference in their values. If the uncorrected values of A1 and B1 are AI' and B, /, then from equation 011), if the corrections to be made are A 1'' and B, //, then from A 1' and B, //, The first term of the equation becomes zero. Then, 5tn-i is a constant. If it is Fl and G1, then A and B1 are ΔPe(i)=A, cos-t+B, 5tn-, ,
t= (A +'A,") cos-Otsu+(Bl
'Bl''C Otsu 1 star (i == 0.1.2,...
..., 2N) ......°・ (xii).

Also, A calculated for each rotation of the backup roll.

The values of and B are sampled by the following equation:

In the figure, (1) is the work roll, (2) is the backing roll, and the pulse signal detected by the pulse generator (3) attached to the shaft end of the backing roll (2) is sent to the Fourier series expansion device (4) and the phase delay. The signal detected by the load cell (6) can be transmitted to the predicted angle determining device (5) of the phase lag, and the signal detected by the load cell (6) can be transmitted to the Fourier series expansion device (4). ) to the Fourier series expansion device (4), and controls the amount and pressure of pressure oil to be sent from the Fourier series expansion device (4) to the hydraulic downstream device (7). ). As shown in the figure, this control system is provided with a position detector, a summing amplifier, etc. for detecting the position of the roll gap setting device and the hydraulic pressure lowering device (7).

Note that (5a) is a speed detector, and (5b) is a setting device for a predicted phase delay angle.

During operation, the pulse generator (3) transmits pulse signals to the Fourier series expansion device (4) and phase delay prediction angle determination device (5), and the rolling load detected by the load cell (3) is transmitted to the Fourier series expansion device (4). 3. The pulse signal is sent to i in the Fourier series expansion device (4).
=Q to i = 1.2.3,...,i,i+1,.
are sequentially counted, Fourier series expansion is performed for each pulse signal, and each Fourier coefficient A, ', B, / is ~11
On the other hand, the roll is calculated by counting the pulse signal detected by the pulse generator (3) and sent to the speed detector (5a) of the phase delay prediction angle determining device (5) for a certain period of time. The number of revolutions per unit time can be calculated. The number of rotations and the frequency are the same per second. Once the number of rotations, that is, the frequency of the roll is known, the phase lag corresponding to that frequency is determined experimentally in advance, and the phase lag prediction angle determining device (
By setting the setting device (5h) in step 5), the predicted phase delay angle The count value of the pulse to be preceded by the count value t is determined, and the rolling load fluctuation Δp e (7, l is determined from equation (xii) based on the above, and the servo valve (
8) to control the hydraulic pressure lowering device (7). There is a phase lag X in the hydraulic lowering device (7), but since the hydraulic lowering device (7) is operated in advance by X in advance, that is, by compensating for the delay, the hydraulic lowering device (7) operates in accordance with the frequency.
is activated, and the influence of roll eccentricity is controlled. .

When roll eccentricity control is performed continuously, it is checked whether the roll has made one revolution, and the slope of the Fourier coefficient corresponding to the current pulse is corrected using the formula (×1)71
The Fourier coefficients are sampled according to the equation (xiii) and used in the next slope correction.The present invention is not limited to the above-mentioned embodiments, and does not depart from the gist of the present invention. Of course, various changes can be made within the scope.

According to the roll eccentricity control device of the present invention, since the rolling phase delay of the hydraulic rolling device is eliminated, the influence of roll eccentricity can be sufficiently eliminated even during acceleration and deceleration of the roll, and therefore the product quality of the rolled plate is improved. The tube can produce various excellent effects.

[Brief explanation of the drawing]

Fig. 1 is a graph showing the relationship between frequency and rolling load, Fig. 2 is an explanatory diagram of the roll eccentricity control device of the present invention, and Fig. 3 is a graph showing the relationship between frequency and rolling load.
FIG. 3 is a diagram showing details of a Fourier series expansion device and a phase delay prediction angle determining device in the device shown in the figure. In the figure, (3) is a Hapulus generator, (4) is a Fourier series expansion device, (5a) is a speed detector, (5b) is a setting device for the predicted phase delay angle, (6) is a load cell, and (7) is a Hydraulic pressure reduction device, (8) indicates a servo valve. 3 Patent applicant Ishikawajima Harima Heavy Industries Co., Ltd.

Claims (1)

[Claims] 1) It has a pulse/enerator for measuring the rotation angle of the backing roll and a device that performs FJ analysis using the rolling load signal detected by the load detector as the fundamental wave of the backing roll period. A device for generating a backup roll eccentricity signal according to a pulse using a Fourier coefficient, which includes a device that counts pulse signals for a certain period of time to determine the eccentricity frequency of the backup roll, and a function unit that outputs a phase corresponding to the frequency, A roll eccentricity control device characterized in that the roll eccentricity is calculated as early as the pulse that adjusts to the phase, and the phase delay under hydraulic pressure is corrected.