JPS607566B2 - Tension control device for continuous hot rolling mill - Google Patents

Description

[Detailed description of the invention] The present invention relates to tension control in continuous hot lubrication rolling,
This invention relates to a method for adaptively correcting the gain of tension control.

In recent years, hot lubrication rolling, in which rolling rolls are coated with lubricating oil (hereinafter simply referred to as oil), has been attracting attention in order to save energy in the rolling process and improve roll consumption.

In this hot lubrication rolling, it is necessary to remove oil adhering to the rolling rolls in order to stabilize the biting of the tip of the next rolled material and the threading of the material. (The oil supply is restarted after the next rolled material is caught. One way to remove this oil is to turn off the oil (stop the oil supply) before the tail end of a certain rolled material comes out of the rolling stand. At this time, some of the oil adhering to the rolling rolls is printed on the rolled material, and some of it is removed by being baked at the temperature of the rolled material.
．． This method has the advantage of not requiring any special equipment to remove the oil, but on the other hand, if the oil is turned on (oil supply starts), the friction between the rolled material and the rolls will be greatly affected when the oil is turned off. This may cause rolling to become unstable. For example, when the oil of a certain rolling stand is turned off, the front tension of the rolling stand will gradually decrease, and the rear tension will conversely increase. This means that the speed (mass flow) of the rolled material passing through the rolling stand with the oil turned off has increased. Of course, loopers or other tension control devices are installed between the stands to improve the width fluctuations that occur with tension fluctuations, but as the amount of oil increases, these tension control devices become more susceptible to this mass flow change. It becomes impossible to follow.

Although only the case where the oil is turned on and off has been described here, similar rolling instability occurs also when the oil supply amount or concentration changes over time.

According to the present invention, when the amount or concentration of oil in any stand is changed to large or medium during rolling, the compensation gain of the tension control system is adaptively corrected in accordance with the amount of change.

FIG. 1 shows an embodiment of a conventional tension control device for continuous hot lubrication rolling. In FIG. 1, 1 is a work roll of rolled material, 2 is a backup roll, 3 is a rolled material, 4 is a tension calculation device, 55 is a speed compensation control device, 6 is a roll drive motor, 7 is a motor speed control device, and 8 is a a nozzle that supplies oil;
9 is oil supply system piping, 1 is an on/off valve for oil supply, 11 is
12 represents an oil amount adjustment device, and 12 represents a flow rate adjustment device.
The tension calculation device 4 detects the inter-stand tension Ti from the rolling process data of the drive motor of each stand rolling roll, the current li, the voltage Vi, the rotation speed i, the rolling load Pi, and the roll function Si, and performs speed compensation control. The device 5 detects the difference △ between the tension Ti and the preset target tension To;
The motor speed compensation control amount is determined from Tj. (For example, there is a method shown in Tokoseki No. 53-85758.
) The oil amount adjusting device 11 opens and closes the valve 10 to control oil supply. For example, a certain period of time after the rolled material 3 is caught in each stand, the valve 10 is turned on to start supplying oil, and a certain period of time before the tail end of the rolled material comes out of that stand, the valve is turned off and oil is supplied. supply will be stopped.
The oil amount when the valve is on is controlled by the flow rate adjustment device 12, and the flow rate instruction is determined by the oil amount adjustment device 11. Here, the flow rate instruction value is determined based on the steel type of the rolled material, the roll surface condition, etc., but the method for determining the flow rate is not related to the gist of the present invention and will therefore be omitted. Figure 2 is the first
This is the result when tension control is performed using the control device shown in the figure.

The rear tension of the stand increases from the time the oil is turned off, and rolling ends with tension offset occurring, which adversely affects the medium dimensions of the rolled material. As mentioned above, the reason for this is that the tension control device is no longer able to follow the change in the mass flow of the rolled material caused by the oil-off. That is, there is a problem in using the conventional fixed control compensation gain. FIG. 3 shows an embodiment of the present invention.

In FIG. 3, 1 to 12 are the same as in FIG. 1, and 13 is a gain adaptive correction device. The gain adaptive correction device 13 adaptively corrects and determines the gains of proportional, integral, and differential control of speed compensation in accordance with the amount of change from the oil amount setting value from the oil amount adjusting device 11. FIG. 4 shows an outline of the speed compensation control device 5 and the gain adaptive correction device 13.

In FIG. 4, 100 is a target tension Toi setting device, 1
01 is the subtractor, 1 02 is PID (proportional, integral, differential)
Arithmetic device, 11: Divider for calculating the ratio n between the oil amount change value △v and the target oil amount change value △vo; A setter 113 for the steady-state gain Ko represents an adder that determines the gain used in the PID calculation unit 102. In the gain adaptive correction device 13, when the oil is turned off, the oil amount change amount △v
, the oil amount change index n is determined by the divider 110 from the target oil amount △vo.
Determine.

n=magazine...[1] Next, the gain correction calculator 111 calculates the gain correction amount ΔKj using the formula [2}.

△Kj{=.

(InI<go) {=k・lnl ('nl≧go) ...■ △; Predetermined constant k; constant that varies depending on proportionality, integration, differentiation, etc. Next, in the adder 113, the PID calculation device 102 Control gain Ki is determined using equation '3} and output.

Ki；Koi＋△Ki…■K
oi; In the steady-state gain PID calculation device, control with good followability is possible even when the oil is off by using the adaptively corrected control gain as described above.

According to this embodiment of the present invention, even when the oil amount changes to medium or high during rolling, tension fluctuations due to the oil amount change can be suppressed.

Note that the present invention provides a means for compensating for tension fluctuations when changing the lubricating oil supply state, so the present invention can be applied similarly even when changing not only the oil amount but also the oil concentration and oil type. is applicable.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an example of a conventional tension control device for continuous hot lubrication rolling, Fig. 2 is a diagram showing actual results of conventional tension control, and Fig. 3 is a diagram showing an example of a tension control device according to the present invention. , FIG. 4 is a diagram showing a gain adaptive correction device of the speed compensation control device of the present invention. DESCRIPTION OF SYMBOLS 1... Work roll, 4... Tension calculation device, 5... Speed compensation control device, 6... Roll drive motor, 7...
Speed control device, 8... Nozzle, 9... Oil supply system piping, 10... Valve, 11... Oil amount adjustment device, 12... Flow rate adjustment device, 13... Gain adaptive correction device. House's diagram 2nd diagram 3rd drawing

Claims (1)

[Claims] 1. In a continuous hot rolling mill that is equipped with a tension calculation unit that calculates tension from a detected value of the rolling quantity of the continuous hot rolling mill and an oil supply device that supplies lubricating oil to the rolling rolls, the tension calculation unit A compensation section that performs at least one of proportional, integral, and differential compensation for the deviation between the tension value obtained by and a preset tension target value, and a proportional, integral, and differential gain of the compensation section in the oil supply device 1. A tension control device for a continuous hot rolling mill, comprising a gain adaptive correction section that determines the oil amount or concentration according to a set oil amount or concentration, or the actual oil amount or concentration.