JPH04200914A - Method for controlling thickness in rolling line - Google Patents

Abstract

PURPOSE:To always obtain the optimum working timing of F.F-AGC and to make the thickness controllable with high accuracy by measuring the inertial masses of a pat-off reel and its driving system and determining the optimum point. CONSTITUTION:The thicknesses of a strip 6 which are measured on the inlet side of rolling roll are successively stored into a tracking circuit 5. On the basis of the whole flywheel effect of the pay-off reel 1 and its driving system, response time and transporting velocity of strip, the thickness at the optimum working point is read from the tracking circuit and the driving motor for pay- off reel is controlled based on the thickness. GD<2>=( pi.r.l)(D<2>-DO<2>).1/8. sigma=E/ L.{Vs(tau)-Vp(tau)} dtau.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a method for controlling plate thickness in a rolling line, particularly in F.F. (backward tension).

[Prior art and problems to be solved by the invention] One of the control methods for controlling plate thickness in a conventional rolling line is F-F-
Control is carried out by AGC, but the optimum operating point for F-F-AGC is the response of the actuator (for example, the response of the hydraulic pressure reduction device or electric pressure reduction system in the case of a reduction system AGC, and the tension or speed in the case of a tension system AGC). response of the operating reel or roll drive system) and F-F-AG
C It is determined by the entrance speed of the target stand.

In the case of the reduction system AGC, the responsiveness of the reduction actuator can be said to be almost constant regardless of the reduction conditions, so the optimum operating point is a linear function of the stand entrance speed.

However, in the case of tension system AGC, the GD2 of the coil system changes as the coil becomes thinner or thicker, so the responsiveness of the drive system changes constantly, making it difficult to control at the optimal operating point. However, there was a problem in that the thickness of the plate could vary.

This invention was made to solve these problems, and is a method for controlling plate thickness in a rolling line that makes it possible to perform control while finding the optimum operating point by calculating GD2 of the reel drive system online. The purpose is to provide a method.

[Means and effects for solving the problem] The thickness control method for a rolling line according to the present invention includes a step of measuring the thickness of the strip at the entrance side of the rolling roll, and sequentially storing the thickness of the strip in a tracking circuit. a step of determining the total flywheel effect of the payoff reel and its drive system; a step of determining the response time based on the total flywheel effect; and a step of determining the optimal operating point based on the response time and the strip transfer speed. , the step of reading the plate thickness at the optimum operating point from the tracking circuit and controlling the drive motor of the payoff reel based on the plate thickness.

[Embodiment] FIG. 1 is a configuration diagram of a control device and related equipment that implement a method for controlling plate thickness in a rolling line according to an embodiment of the present invention. In the figure, (1) is a payoff reel, (2) is a deflector roll, (3) is a rolling roll, and (4) is a payoff reel.
is the plate thickness gauge. (5) is a tracking circuit composed of, for example, a FIFO, etc., and sequentially takes in the output of the plate thickness gauge (4) at a fixed timing. (6) is a strip sent out from the payoff reel (1); (7) is a rotation detector that detects the rotation speed of the payoff reel (1);
(8) is a rotation detector that detects the rotation speed of the deflector roll (2).

(10) is an arithmetic processing circuit, and data from the tracking circuit (5) is read out based on its output. (11) is its division circuit, (12) to (1B), (1,8),
(21) is a multiplier, (17) is a subtracter, and (19
) is an adder.

(20) is a function generator, which outputs a response time corresponding to GD2. (30) is a control circuit, which calculates the control current of the drive motor (not shown) of the payoff reel (1) based on the data read out from the tracking circuit (5) by the arithmetic processing circuit (10). 7. This controls the drive motor.

In the control device configured as described above, the rotation detectors (7) and (8) determine the rotation speed Nl of the payoff reel (1) and deflector roll (2), respectively.

N2 is detected and outputted to the arithmetic processing circuit (JO). The divider (11) calculates the rotation speed N2. Ratio to NL N2/
N1 is determined, and the multiplier (12) calculates the product of the ratio N2 /NL and the diameter D2 (constant) of the deflector roll (2>).
(N2 /Nl)XD21 is determined, and the diameter of the payoff reel (1) at that time is determined. The diameter obtained as described above is multiplied by the multipliers (13) and (14) to obtain the square value D2 of the diameter.

On the other hand, the multipliers (15) and (1G) calculate the square value D02 of the inner diameter DO (constant) of the payoff reel (+,), and the subtracter (17) calculates the difference (D2-D) between D and DO.
O2) is determined. Next, the multiplier (18) multiplies the difference by a constant (π・γ・l) to generate a payoff reel (
1) Find GD2. In other words, GD2 expressed by the following equation is obtained.

γ, Specific weight of strip (6) 1; Width of strip (6) Next, an adder (19) adds GD2 of the payoff reel (1) and GDm2 of the drive motor system to obtain the entire drive system. Find GDa2.

By the way, the tension fluctuation between the rolling stand and the payoff reel (1) is determined by the following equation.

σ=E/L ・(Vs (r)−Vp (r)l
dr...(2) E; Young's modulus L; stand-reel distance VS, stand roll circumferential speed vp: payoff reel circumferential speed Here, if the stand roll circumferential speed is constant, when the tension system is The constant depends on the responsiveness of the peripheral speed of the payoff reel (1). This responsiveness is expressed as a function of the total GDa2 of the drive system, and by determining the relationship between the total GDa2 and the response time in advance by conducting a test on an actual machine, the relationship between the two can be obtained.

FIG. 2 is a characteristic diagram showing a specific example of a function in the function generator (20), and shows data obtained by an actual machine as shown in two series.

The function generator (20) generates the total GDa2 from the adder (19)
Find the response time t based on . Then, the multiplier (21
) is the speed Vin of the strip (0), for example a rotation detector (
8) and the response time t, that is, the distance l" corresponding to the response time t. The tracking circuit (5) calculates the plate thickness data based on this distance of 1°, that is, the rolling roll (3)
Output the thickness data of the strip (6) that is 1° closer than the strip.

The control circuit (30) performs a predetermined calculation similar to the conventional method based on the thickness data, using the distance 1'' as the optimum operating point, and controls the drive motor based on the calculation result.

In the above-described embodiment, the multiplier and the like are illustrated and explained in the arithmetic processing circuit (10), but it goes without saying that the same arithmetic function can be obtained by software.

[Effects of the Invention] As described above, according to the present invention, the GD2 of the payoff reel and its drive system is measured and the optimum operating point is determined based on it, so that the optimum F-F-A is always maintained.
The GC operation timing is obtained, and the plate thickness is controlled with high precision over the entire length of the coil.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a control device and related equipment implementing a control method according to an embodiment of the present invention, and FIG. 2 is a characteristic diagram of a function generator. Agent Patent Attorney Muneharu Sasaki

Claims (1)

[Claims] A step of measuring the thickness of the strip at the entrance side of the rolling roll, a step of sequentially storing the thickness of the strip in a tracking circuit, and determining the total flywheel effect of the payoff reel and its drive system. a step of determining a response time based on the total flywheel effect; a step of determining an optimal operating point based on the response time and the transport speed of the strip; and reading out the plate thickness at the optimal operating point from a tracking circuit and determining its value. 1. A method for controlling plate thickness in a rolling line, comprising the step of controlling a drive motor for a payoff reel based on the plate thickness.